import { nanoid } from "nanoid"
import type {
  Gradient,
  PPTElement,
  PPTElementShadow,
  PPTImageElement,
  PPTVideoElement,
  PPTEnjoyElement,
  PPTCloudCoachElement,
  PPTLineElement,
  PPTAnimation,
  PPTShapeElement,
  PPTTextElement,
  Slide,
  SlideBackground,
  SlideTheme
} from "@/types/slides"
import type { AiCoursewareOutline, AiCoursewarePage } from "@/api/aiCourseware"
import { getAiCoursewarePalette, type AiCoursewareTemplateId, type AiCoursewareThemePalette } from "@/config/aiCoursewareTemplates"

interface AiPptOptions {
  backgroundImage?: string
  enableAnimations?: boolean
  paletteVariant?: number
  templateId?: AiCoursewareTemplateId
}

type PageRole =
  | "cover"
  | "intro"
  | "goal"
  | "story"
  | "listen"
  | "lyric"
  | "notation"
  | "instrument"
  | "compare"
  | "knowledge"
  | "rhythm"
  | "interaction"
  | "performance"
  | "practice"
  | "activity"
  | "summary"
  | "homework"
  | "content"

type Palette = AiCoursewareThemePalette

interface ImageRect {
  left: number
  top: number
  width: number
  height: number
  radius?: number
}

const SLIDE_WIDTH = 1600
const SLIDE_HEIGHT = 900
const VIEWPORT_WIDTH = 1920
const VIEWPORT_HEIGHT = 1080
const VIEWPORT_SCALE = VIEWPORT_WIDTH / SLIDE_WIDTH
const FONT_NAME = "Microsoft Yahei"
const GENERIC_PAGE_TITLES = new Set(["封面", "课程导入", "故事导入", "导入", "首页", "cover"])

export function buildAiPptSlides(
  outline: AiCoursewareOutline,
  options: AiPptOptions = {}
): { title: string; theme: Partial<SlideTheme>; slides: Slide[] } {
  const normalized = normalizeOutline(outline)
  const palette = buildPalette(normalized, options.paletteVariant || 0, options.templateId)
  const slides = normalized.pages.map((page, index) => buildSlide(page, normalized, palette, options, index))
  runPreflight(slides)
  return {
    title: normalized.title || normalized.chapterName || "音乐课件",
    theme: {
      themeColor: palette.primary,
      backgroundColor: palette.background,
      fontColor: palette.text,
      fontName: FONT_NAME,
      fontSize: "36px"
    },
    slides
  }
}

function buildSlide(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette, options: AiPptOptions, index: number): Slide {
  const role = pageRole(page, index)
  const dedicatedResource = dedicatedResourceElement(page)
  const contentElements = dedicatedResource
    ? [dedicatedResource]
    : videoBinding(page)
      ? videoResourceTemplate(page, outline, palette)
      : [...templateForPage(page, role)(page, outline, palette, index), ...inlineResourceElements(page)]
  const elements = dedicatedResource ? contentElements : [...templateDecorationElements(options.templateId, palette, role), ...contentElements]
  return {
    id: nanoid(10),
    elements: scaleElementsToViewport(keepInCanvas(elements)),
    background: backgroundConfig(role, palette, options),
    remark: slideRemark(page),
    animations: options.enableAnimations ? entranceAnimations(contentElements) : undefined,
    turningMode: options.enableAnimations ? "fade" : "no"
  }
}

function templateDecorationElements(templateId: AiCoursewareTemplateId | undefined, palette: Palette, role: PageRole): PPTElement[] {
  if (!templateId || role === "cover") return []
  switch (templateId) {
    case "playful-handdrawn":
      return [
        shapeElement({ left: 1450, top: 36, width: 74, height: 74, fill: palette.warm, opacity: 0.5, radius: 37 }),
        shapeElement({ left: 1518, top: 92, width: 42, height: 42, fill: palette.accent, opacity: 0.45, radius: 21 }),
        shapeElement({ left: 26, top: 792, width: 58, height: 58, fill: palette.secondary, opacity: 0.26, radius: 29 })
      ]
    case "fresh-education":
      return [
        shapeElement({ left: 0, top: 0, width: 1600, height: 12, fill: palette.secondary, opacity: 0.85, radius: 0 }),
        shapeElement({ left: 1530, top: 742, width: 70, height: 158, fill: palette.soft, opacity: 0.8, radius: 0 })
      ]
    case "academic-blue":
      return [
        shapeElement({ left: 0, top: 0, width: 1600, height: 18, fill: palette.primary, radius: 0 }),
        shapeElement({ left: 1548, top: 38, width: 18, height: 132, fill: palette.accent, radius: 0 }),
        shapeElement({ left: 1574, top: 38, width: 8, height: 84, fill: palette.secondary, radius: 0 })
      ]
    case "oriental-culture":
      return [
        shapeElement({ left: 1460, top: 42, width: 88, height: 88, fill: palette.primary, opacity: 0.14, radius: 44 }),
        shapeElement({ left: 1499, top: 52, width: 10, height: 68, fill: palette.primary, opacity: 0.62, radius: 2 }),
        shapeElement({ left: 1434, top: 148, width: 114, height: 4, fill: palette.accent, opacity: 0.55, radius: 2 })
      ]
    case "digital-tech":
      return [
        shapeElement({ left: 80, top: 120, width: 1440, height: 2, fill: palette.secondary, opacity: 0.16, radius: 0 }),
        shapeElement({ left: 80, top: 780, width: 1440, height: 2, fill: palette.primary, opacity: 0.16, radius: 0 }),
        shapeElement({ left: 118, top: 80, width: 2, height: 740, fill: palette.secondary, opacity: 0.12, radius: 0 }),
        shapeElement({ left: 1480, top: 80, width: 2, height: 740, fill: palette.primary, opacity: 0.12, radius: 0 }),
        shapeElement({ left: 1468, top: 108, width: 26, height: 26, fill: palette.secondary, opacity: 0.75, radius: 4 })
      ]
    case "active-classroom":
      return [
        shapeElement({ left: 1390, top: 30, width: 58, height: 18, fill: palette.accent, radius: 9 }),
        shapeElement({ left: 1458, top: 30, width: 92, height: 18, fill: palette.secondary, radius: 9 }),
        shapeElement({ left: 44, top: 816, width: 116, height: 20, fill: palette.warm, opacity: 0.8, radius: 10 })
      ]
  }
}

function entranceAnimations(elements: PPTElement[]): PPTAnimation[] {
  return elements
    .filter(
      element => (element.type === "text" || element.type === "image" || element.type === "shape") && element.width >= 120 && element.height >= 45
    )
    .slice(0, 6)
    .map((element, index) => ({
      id: nanoid(10),
      elId: element.id,
      effect: index === 0 ? "fadeIn" : "fadeInUp",
      type: "in",
      duration: 500,
      trigger: index === 0 ? "auto" : "click"
    }))
}

function templateForPage(page: AiCoursewarePage, role: PageRole) {
  const layout = cleanText(page.visualPlan?.layout || page.visual?.layout).toLowerCase()
  switch (layout) {
    case "cover_scene":
      return coverTemplate
    case "full_image_question":
      return immersiveImageTemplate
    case "split_image":
      return storyTemplate
    case "goal_cards":
      return goalTemplate
    case "listen_wave":
      return listenTemplate
    case "lyric_focus":
      return lyricTemplate
    case "score_focus":
      return notationTemplate
    case "rhythm_grid":
      return rhythmTemplate
    case "instrument_focus":
      return instrumentTemplate
    case "compare_listen":
      return compareTemplate
    case "knowledge_cards":
      return knowledgeTemplate
    case "activity_steps":
      return activityTemplate
    case "practice_check":
      return practiceTemplate
    case "summary_checklist":
      return summaryTemplate
    case "homework_list":
      return homeworkTemplate
    case "story_stage":
      return storyStageTemplate
    case "observe_question":
      return observeQuestionTemplate
    case "listen_compare_visual":
      return listenCompareVisualTemplate
    case "sound_timeline":
      return soundTimelineTemplate
    case "action_demo":
      return actionDemoTemplate
    case "group_mission":
      return groupMissionTemplate
    case "performance_stage":
      return performanceStageTemplate
    case "visual_summary":
      return visualSummaryTemplate
    default:
      return templateForRole(role)
  }
}

function templateForRole(role: PageRole) {
  switch (role) {
    case "cover":
      return coverTemplate
    case "goal":
      return goalTemplate
    case "listen":
      return listenTemplate
    case "lyric":
      return lyricTemplate
    case "notation":
      return notationTemplate
    case "instrument":
      return instrumentTemplate
    case "compare":
      return compareTemplate
    case "rhythm":
      return rhythmTemplate
    case "knowledge":
      return knowledgeTemplate
    case "interaction":
      return interactionTemplate
    case "performance":
      return performanceTemplate
    case "practice":
      return practiceTemplate
    case "activity":
      return activityTemplate
    case "summary":
      return summaryTemplate
    case "homework":
      return homeworkTemplate
    case "intro":
    case "story":
      return storyTemplate
    default:
      return contentTemplate
  }
}

function immersiveImageTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette, index: number): PPTElement[] {
  if (!hasImage(page)) return storyTemplate(page, outline, palette, index)
  const title = displayPageTitle(page, outline)
  const question = page.interaction?.question || activityTask(page) || studentHeadline(page) || studentPoints(page, 1)[0]
  const panelOnLeft = index % 2 === 0
  const panelLeft = panelOnLeft ? 0 : 930
  const textLeft = panelOnLeft ? 104 : 1010
  const elements: PPTElement[] = [imageElement(page, { left: 0, top: 0, width: SLIDE_WIDTH, height: SLIDE_HEIGHT })]
  elements.push(shapeElement({ left: panelLeft, top: 0, width: 670, height: 900, fill: palette.dark, opacity: 0.82, radius: 0 }))
  elements.push(
    textElement({
      left: textLeft,
      top: 110,
      width: 480,
      height: 48,
      content: page.teachingStage || "观察与发现",
      fontSize: 22,
      color: palette.warm,
      bold: true
    })
  )
  elements.push(
    textElement({
      left: textLeft,
      top: 188,
      width: 500,
      height: 160,
      content: title,
      fontSize: fitFont(title, 500, 160, 56, 40),
      color: "#FFFFFF",
      bold: true
    })
  )
  elements.push(shapeElement({ left: textLeft, top: 382, width: 94, height: 10, fill: palette.accent, radius: 4 }))
  if (question) {
    elements.push(
      textElement({
        left: textLeft,
        top: 454,
        width: 500,
        height: 200,
        content: question,
        fontSize: fitFont(question, 500, 200, 38, 28),
        color: "#FFFFFF",
        bold: true,
        lineHeight: 1.35
      })
    )
  }
  return elements
}

function coverTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const title = chapterTitle(outline, page)
  const subtitle = [outline.gradeName, conciseTextbook(outline.textbookName), outline.unitName].filter(Boolean).join(" · ")
  const points = studentPoints(page, 2)
  if (hasImage(page)) {
    const elements: PPTElement[] = [shapeElement({ left: 0, top: 0, width: SLIDE_WIDTH, height: SLIDE_HEIGHT, fill: palette.dark, radius: 0 })]
    // 教材原图只作为经过裁切的主视觉使用，避免整张扫描页直接成为封面。
    elements.push(imageElement(page, { left: 650, top: 0, width: 950, height: 900 }))
    elements.push(shapeElement({ left: 570, top: 0, width: 240, height: 900, fill: palette.dark, opacity: 0.62, radius: 0 }))
    elements.push(
      textElement({
        left: 100,
        top: 150,
        width: 470,
        height: 150,
        content: title,
        fontSize: fitFont(title, 470, 150, 66, 44),
        color: "#FFFFFF",
        bold: true
      })
    )
    if (subtitle) elements.push(textElement({ left: 104, top: 330, width: 470, height: 72, content: subtitle, fontSize: 24, color: "#EAF2F7" }))
    elements.push(shapeElement({ left: 104, top: 430, width: 84, height: 10, fill: palette.accent, radius: 4 }))
    points.forEach((point, index) =>
      elements.push(
        textElement({
          left: 104,
          top: 500 + index * 64,
          width: 470,
          height: 44,
          content: point,
          fontSize: fitFont(point, 470, 44, 28, 22),
          color: "#FFFFFF",
          bold: index === 0
        })
      )
    )
    return elements
  }

  const elements: PPTElement[] = []
  elements.push(shapeElement({ left: 0, top: 0, width: 560, height: 900, fill: palette.primary, radius: 0 }))
  elements.push(shapeElement({ left: 560, top: 0, width: 1040, height: 900, fill: palette.background, radius: 0 }))
  elements.push(textElement({ left: 92, top: 112, width: 380, height: 70, content: "音乐课堂", fontSize: 30, color: "#FFFFFF", bold: true }))
  elements.push(
    textElement({
      left: 650,
      top: 170,
      width: 780,
      height: 170,
      content: title,
      fontSize: fitFont(title, 780, 170, 70, 50),
      color: palette.primary,
      bold: true
    })
  )
  if (subtitle) elements.push(textElement({ left: 656, top: 370, width: 740, height: 44, content: subtitle, fontSize: 24, color: palette.muted }))
  elements.push(textElement({ left: 92, top: 360, width: 380, height: 180, content: "听 · 唱 · 动", fontSize: 52, color: "#FFFFFF", bold: true }))
  elements.push(shapeElement({ left: 654, top: 486, width: 120, height: 10, fill: palette.secondary, radius: 4 }))
  points.forEach((point, index) =>
    elements.push(
      textElement({
        left: 656,
        top: 548 + index * 66,
        width: 720,
        height: 46,
        content: point,
        fontSize: fitFont(point, 720, 46, 30, 23),
        color: palette.text,
        bold: index === 0
      })
    )
  )
  return elements
}

function storyTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette, index: number): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "进入情境")
  const imageLeft = index % 2 === 0
  if (hasImage(page)) {
    const imageRect = imageLeft
      ? { left: 86, top: 190, width: 860, height: 560, radius: 8 }
      : { left: 654, top: 190, width: 860, height: 560, radius: 8 }
    elements.push(imageElement(page, imageRect))
    const panelLeft = imageLeft ? 1010 : 86
    elements.push(shapeElement({ left: panelLeft, top: 230, width: 500, height: 470, fill: palette.surface, radius: 8, shadow: softShadow() }))
    elements.push(...studentPanel(page, palette, panelLeft + 42, 278, 416))
  } else {
    elements.push(shapeElement({ left: 86, top: 210, width: 1428, height: 480, fill: palette.surface, radius: 8, shadow: softShadow() }))
    elements.push(
      textElement({
        left: 156,
        top: 270,
        width: 1280,
        height: 90,
        content: studentHeadline(page) || page.title,
        fontSize: fitFont(studentHeadline(page) || page.title, 1280, 90, 42, 30),
        color: palette.primary,
        bold: true
      })
    )
    elements.push(...storySequence(studentPoints(page, 4), palette, 156, 420, 1280))
  }
  addClassroomCue(elements, page, palette)
  return elements
}

function storyStageTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const title = displayPageTitle(page, outline)
  const points = studentPoints(page, 2)
  const elements: PPTElement[] = []
  if (hasImage(page)) elements.push(imageElement(page, { left: 0, top: 0, width: 1600, height: 900 }))
  else {
    elements.push(shapeElement({ left: 0, top: 0, width: 1600, height: 900, fill: palette.soft, radius: 0 }))
    elements.push(shapeElement({ left: 0, top: 420, width: 1600, height: 480, fill: palette.primary, opacity: 0.16, radius: 0 }))
  }
  elements.push(shapeElement({ left: 0, top: 0, width: 1600, height: 190, fill: palette.dark, opacity: 0.76, radius: 0 }))
  elements.push(
    textElement({
      left: 92,
      top: 54,
      width: 1320,
      height: 94,
      content: title,
      fontSize: fitFont(title, 1320, 94, 52, 38),
      color: "#FFFFFF",
      bold: true
    })
  )
  const dialogue = points[0] || activityTask(page)
  if (dialogue) {
    elements.push(shapeElement({ left: 130, top: 590, width: 1120, height: 190, fill: "#FFFFFF", opacity: 0.94, radius: 22, shadow: softShadow() }))
    elements.push(
      textElement({
        left: 186,
        top: 632,
        width: 1000,
        height: 100,
        content: dialogue,
        fontSize: fitFont(dialogue, 1000, 100, 38, 28),
        color: palette.text,
        bold: true,
        lineHeight: 1.3
      })
    )
    elements.push(shapeElement({ left: 1280, top: 620, width: 180, height: 120, fill: palette.accent, radius: 60 }))
  }
  return elements
}

function observeQuestionTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "观察与发现")
  const question = page.interaction?.question || activityTask(page) || studentPoints(page, 1)[0]
  if (hasImage(page)) elements.push(imageElement(page, { left: 70, top: 190, width: 940, height: 570, radius: 18 }))
  else elements.push(shapeElement({ left: 70, top: 190, width: 940, height: 570, fill: palette.soft, radius: 18 }))
  elements.push(shapeElement({ left: 1060, top: 220, width: 440, height: 500, fill: palette.surface, radius: 18, shadow: softShadow() }))
  elements.push(shapeElement({ left: 1110, top: 274, width: 72, height: 72, fill: palette.accent, radius: 36 }))
  elements.push(textElement({ left: 1131, top: 283, width: 34, height: 48, content: "?", fontSize: 38, color: "#FFFFFF", bold: true }))
  elements.push(
    textElement({
      left: 1110,
      top: 390,
      width: 330,
      height: 190,
      content: question || "你发现了什么？",
      fontSize: fitFont(question || "你发现了什么？", 330, 190, 38, 27),
      color: palette.text,
      bold: true,
      lineHeight: 1.35
    })
  )
  return elements
}

function listenCompareVisualTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "听辨对比")
  const points = studentPoints(page, 4)
  ;[0, 1].forEach(group => {
    const left = group === 0 ? 84 : 820
    const color = group === 0 ? palette.primary : palette.secondary
    elements.push(
      shapeElement({ left, top: 205, width: 696, height: 500, fill: group === 0 ? palette.soft : palette.surface, radius: 18, shadow: lightShadow() })
    )
    elements.push(shapeElement({ left: left + 40, top: 250, width: 82, height: 82, fill: color, radius: 41 }))
    elements.push(
      textElement({ left: left + 65, top: 268, width: 34, height: 46, content: group === 0 ? "A" : "B", fontSize: 32, color: "#FFFFFF", bold: true })
    )
    for (let bar = 0; bar < 8; bar++) {
      const height = 28 + ((bar * 23 + group * 17) % 86)
      elements.push(shapeElement({ left: left + 170 + bar * 48, top: 350 - height / 2, width: 22, height, fill: color, opacity: 0.72, radius: 8 }))
    }
    const text = points[group] || (group === 0 ? "听第一段声音" : "听第二段声音")
    elements.push(
      textElement({
        left: left + 54,
        top: 470,
        width: 580,
        height: 110,
        content: text,
        fontSize: fitFont(text, 580, 110, 34, 25),
        color: palette.text,
        bold: true
      })
    )
  })
  return elements
}

function soundTimelineTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "声音变化")
  const points = studentPoints(page, 4)
  elements.push(lineElement(170, 480, 1430, 480, palette.muted, 6))
  points.forEach((point, index) => {
    const left = 180 + index * (1200 / Math.max(1, points.length - 1))
    const size = index % 2 === 0 ? 82 : 54
    const color = index % 2 === 0 ? palette.primary : palette.secondary
    elements.push(shapeElement({ left: left - size / 2, top: 480 - size / 2, width: size, height: size, fill: color, radius: size / 2 }))
    elements.push(
      textElement({
        left: left - 150,
        top: index % 2 === 0 ? 300 : 570,
        width: 300,
        height: 90,
        content: point,
        fontSize: fitFont(point, 300, 90, 30, 23),
        color: palette.text,
        bold: true,
        lineHeight: 1.3
      })
    )
  })
  return elements
}

function actionDemoTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "跟着做")
  const steps = activitySteps(page, 4)
  steps.forEach((step, index) => {
    const left = 110 + index * 370
    const color = [palette.primary, palette.secondary, palette.accent, palette.warm][index]
    elements.push(shapeElement({ left, top: 280, width: 190, height: 190, fill: color, radius: 95, shadow: lightShadow() }))
    elements.push(
      textElement({ left: left + 62, top: 326, width: 70, height: 74, content: `${index + 1}`, fontSize: 54, color: "#FFFFFF", bold: true })
    )
    elements.push(
      textElement({
        left: left - 45,
        top: 530,
        width: 280,
        height: 110,
        content: step,
        fontSize: fitFont(step, 280, 110, 31, 23),
        color: palette.text,
        bold: true,
        lineHeight: 1.3
      })
    )
    if (index < steps.length - 1) elements.push(lineElement(left + 220, 376, left + 330, 376, palette.muted, 4))
  })
  return elements
}

function groupMissionTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "小组任务")
  const steps = activitySteps(page, 4)
  steps.forEach((step, index) => {
    const top = 210 + index * 142
    const color = index % 2 === 0 ? palette.primary : palette.secondary
    elements.push(shapeElement({ left: 100, top, width: 150, height: 104, fill: color, radius: 16 }))
    elements.push(
      textElement({ left: 126, top: top + 27, width: 100, height: 45, content: `第${index + 1}组`, fontSize: 27, color: "#FFFFFF", bold: true })
    )
    elements.push(lineElement(270, top + 52, 350, top + 52, color, 4))
    elements.push(
      textElement({
        left: 390,
        top: top + 18,
        width: 1030,
        height: 68,
        content: step,
        fontSize: fitFont(step, 1030, 68, 34, 25),
        color: palette.text,
        bold: true
      })
    )
  })
  return elements
}

function performanceStageTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "展示时刻")
  elements.push(shapeElement({ left: 130, top: 220, width: 1340, height: 520, fill: palette.dark, radius: 28, shadow: softShadow() }))
  elements.push(shapeElement({ left: 230, top: 300, width: 1140, height: 360, fill: palette.warm, opacity: 0.24, radius: 180 }))
  const roles = activitySteps(page, 4)
  roles.forEach((role, index) => {
    const left = 300 + index * 270
    elements.push(shapeElement({ left, top: 430, width: 130, height: 130, fill: index % 2 ? palette.secondary : palette.accent, radius: 65 }))
    elements.push(
      textElement({
        left: left - 30,
        top: 590,
        width: 190,
        height: 68,
        content: role,
        fontSize: fitFont(role, 190, 68, 27, 21),
        color: "#FFFFFF",
        bold: true
      })
    )
  })
  return elements
}

function visualSummaryTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "今天的发现")
  const points = studentPoints(page, 4)
  points.forEach((point, index) => {
    const left = 170 + index * 350
    const top = index % 2 === 0 ? 310 : 500
    const color = [palette.primary, palette.secondary, palette.accent, palette.warm][index]
    elements.push(shapeElement({ left, top, width: 110, height: 110, fill: color, radius: 55 }))
    elements.push(textElement({ left: left + 38, top: top + 27, width: 40, height: 50, content: "✓", fontSize: 38, color: "#FFFFFF", bold: true }))
    elements.push(
      textElement({
        left: left - 70,
        top: top + 135,
        width: 250,
        height: 86,
        content: point,
        fontSize: fitFont(point, 250, 86, 29, 22),
        color: palette.text,
        bold: true,
        lineHeight: 1.3
      })
    )
    if (index < points.length - 1) elements.push(lineElement(left + 130, top + 55, left + 300, index % 2 === 0 ? 555 : 365, palette.muted, 3))
  })
  return elements
}

function goalTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "本课目标")
  const points = studentPoints(page, 3)
  points.forEach((point, index) => {
    const left = 92 + index * 500
    const colors = [palette.primary, palette.secondary, palette.accent]
    elements.push(shapeElement({ left, top: 240, width: 430, height: 380, fill: palette.surface, radius: 8, shadow: softShadow() }))
    elements.push(shapeElement({ left, top: 240, width: 430, height: 18, fill: colors[index], radius: 0 }))
    elements.push(
      textElement({ left: left + 34, top: 300, width: 96, height: 74, content: `0${index + 1}`, fontSize: 50, color: colors[index], bold: true })
    )
    elements.push(
      textElement({
        left: left + 34,
        top: 410,
        width: 350,
        height: 120,
        content: point,
        fontSize: fitFont(point, 350, 120, 32, 25),
        color: palette.text,
        bold: true,
        lineHeight: 1.35
      })
    )
  })
  addClassroomCue(elements, page, palette)
  return elements
}

function listenTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "听赏任务")
  const task = activityTask(page) || studentHeadline(page) || "安静聆听，找一找音乐中的声音"
  if (hasImage(page)) {
    elements.push(imageElement(page, { left: 84, top: 185, width: 1432, height: 520, radius: 8 }))
    elements.push(shapeElement({ left: 84, top: 510, width: 1432, height: 195, fill: palette.dark, opacity: 0.8, radius: 0 }))
    elements.push(
      textElement({
        left: 130,
        top: 550,
        width: 1340,
        height: 84,
        content: task,
        fontSize: fitFont(task, 1340, 84, 42, 30),
        color: "#FFFFFF",
        bold: true
      })
    )
  } else {
    elements.push(shapeElement({ left: 92, top: 210, width: 1416, height: 220, fill: palette.dark, radius: 8 }))
    elements.push(
      textElement({
        left: 150,
        top: 270,
        width: 1300,
        height: 92,
        content: task,
        fontSize: fitFont(task, 1300, 92, 44, 30),
        color: "#FFFFFF",
        bold: true
      })
    )
    elements.push(...studentPanel(page, palette, 170, 500, 1260))
  }
  addClassroomCue(elements, page, palette)
  return elements
}

function lyricTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "学唱与歌词")
  const points = studentPoints(page, 4)
  elements.push(shapeElement({ left: 90, top: 205, width: 1420, height: 470, fill: palette.surface, radius: 8, shadow: softShadow() }))
  elements.push(shapeElement({ left: 90, top: 205, width: 26, height: 470, fill: palette.secondary, radius: 0 }))
  points.forEach((point, index) => {
    const top = 265 + index * 92
    elements.push(
      textElement({
        left: 166,
        top,
        width: 1250,
        height: 58,
        content: point,
        fontSize: fitFont(point, 1250, 58, 36, 27),
        color: index % 2 === 0 ? palette.text : palette.primary,
        bold: index % 2 === 1
      })
    )
  })
  addClassroomCue(elements, page, palette)
  return elements
}

function notationTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "旋律与谱例")
  const headline = studentHeadline(page) || "看一看，唱一唱"
  elements.push(
    textElement({
      left: 92,
      top: 190,
      width: 1416,
      height: 72,
      content: headline,
      fontSize: fitFont(headline, 1416, 72, 40, 30),
      color: palette.primary,
      bold: true
    })
  )
  elements.push(...knowledgeList(studentPoints(page, 3), palette, 92, 310, 1416))
  addClassroomCue(elements, page, palette)
  return elements
}

function instrumentTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "认识声音")
  const points = studentPoints(page, 3)
  if (hasImage(page)) {
    elements.push(imageElement(page, { left: 84, top: 190, width: 760, height: 540, radius: 8 }))
    elements.push(
      textElement({
        left: 920,
        top: 220,
        width: 580,
        height: 96,
        content: studentHeadline(page) || page.title,
        fontSize: fitFont(studentHeadline(page) || page.title, 580, 96, 42, 30),
        color: palette.primary,
        bold: true
      })
    )
    points.forEach((point, index) => {
      const top = 360 + index * 104
      elements.push(
        textElement({
          left: 920,
          top,
          width: 56,
          height: 48,
          content: `0${index + 1}`,
          fontSize: 30,
          color: index % 2 ? palette.secondary : palette.accent,
          bold: true
        })
      )
      elements.push(
        textElement({
          left: 992,
          top,
          width: 490,
          height: 64,
          content: point,
          fontSize: fitFont(point, 490, 64, 30, 23),
          color: palette.text,
          bold: true
        })
      )
    })
  } else {
    elements.push(shapeElement({ left: 92, top: 210, width: 1416, height: 190, fill: palette.primary, radius: 8 }))
    elements.push(
      textElement({
        left: 150,
        top: 260,
        width: 1300,
        height: 90,
        content: studentHeadline(page) || page.title,
        fontSize: fitFont(studentHeadline(page) || page.title, 1300, 90, 44, 30),
        color: "#FFFFFF",
        bold: true
      })
    )
    elements.push(...knowledgeList(points, palette, 170, 470, 1260))
  }
  addClassroomCue(elements, page, palette)
  return elements
}

function compareTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "对比听赏")
  const points = studentPoints(page, 4)
  const leftPoints = points.filter((_, index) => index % 2 === 0)
  const rightPoints = points.filter((_, index) => index % 2 === 1)
  elements.push(shapeElement({ left: 92, top: 210, width: 690, height: 470, fill: palette.soft, radius: 8 }))
  elements.push(shapeElement({ left: 818, top: 210, width: 690, height: 470, fill: palette.surface, radius: 8, shadow: lightShadow() }))
  elements.push(textElement({ left: 140, top: 252, width: 570, height: 64, content: "听一听 A", fontSize: 36, color: palette.primary, bold: true }))
  elements.push(textElement({ left: 866, top: 252, width: 570, height: 64, content: "听一听 B", fontSize: 36, color: palette.secondary, bold: true }))
  ;[leftPoints, rightPoints].forEach((items, group) =>
    items.forEach((point, index) => {
      const left = group === 0 ? 140 : 866
      const top = 365 + index * 110
      elements.push(shapeElement({ left, top: top + 8, width: 22, height: 22, fill: group === 0 ? palette.primary : palette.secondary, radius: 8 }))
      elements.push(
        textElement({
          left: left + 48,
          top,
          width: 520,
          height: 70,
          content: point,
          fontSize: fitFont(point, 520, 70, 30, 23),
          color: palette.text,
          bold: true
        })
      )
    })
  )
  addClassroomCue(elements, page, palette)
  return elements
}

function rhythmTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "节奏练习")
  const task = activityTask(page) || studentHeadline(page) || "拍一拍，感受节奏"
  elements.push(
    textElement({
      left: 92,
      top: 190,
      width: 1410,
      height: 72,
      content: task,
      fontSize: fitFont(task, 1410, 72, 40, 30),
      color: palette.text,
      bold: true
    })
  )
  const beats = activitySteps(page, 4)
  beats.forEach((beat, index) => {
    const left = 92 + index * 370
    elements.push(
      shapeElement({
        left,
        top: 330,
        width: 320,
        height: 260,
        fill: index % 2 === 0 ? palette.soft : palette.surface,
        radius: 8,
        shadow: lightShadow()
      })
    )
    elements.push(
      textElement({
        left: left + 28,
        top: 370,
        width: 70,
        height: 56,
        content: `${index + 1}`,
        fontSize: 42,
        color: index % 2 === 0 ? palette.primary : palette.secondary,
        bold: true
      })
    )
    elements.push(
      textElement({
        left: left + 28,
        top: 460,
        width: 260,
        height: 90,
        content: beat,
        fontSize: fitFont(beat, 260, 90, 29, 23),
        color: palette.text,
        bold: true,
        lineHeight: 1.3
      })
    )
  })
  addClassroomCue(elements, page, palette)
  return elements
}

function knowledgeTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette, index: number): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "音乐知识")
  const points = studentPoints(page, 4)
  if (hasImage(page)) {
    const imageRight = index % 2 === 0
    elements.push(
      imageElement(
        page,
        imageRight ? { left: 900, top: 190, width: 610, height: 500, radius: 8 } : { left: 90, top: 190, width: 610, height: 500, radius: 8 }
      )
    )
    elements.push(...knowledgeList(points, palette, imageRight ? 90 : 770, 220, 720))
  } else {
    elements.push(...knowledgeList(points, palette, 90, 220, 1420))
  }
  addClassroomCue(elements, page, palette)
  return elements
}

function interactionTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "互动挑战")
  const candidate = page.interaction?.question || activityTask(page) || studentHeadline(page) || "你发现了什么？"
  const question = sameVisibleText(candidate, page.title) ? "" : candidate
  if (question) {
    elements.push(shapeElement({ left: 90, top: 200, width: 1420, height: 190, fill: palette.primary, radius: 8 }))
    elements.push(
      textElement({
        left: 150,
        top: 245,
        width: 1300,
        height: 100,
        content: question,
        fontSize: fitFont(question, 1300, 100, 44, 30),
        color: "#FFFFFF",
        bold: true
      })
    )
  }
  const steps = activitySteps(page, 3)
  steps.forEach((step, index) => {
    const left = 90 + index * 490
    elements.push(
      textElement({
        left,
        top: 468,
        width: 88,
        height: 54,
        content: `0${index + 1}`,
        fontSize: 40,
        color: [palette.primary, palette.secondary, palette.accent][index],
        bold: true
      })
    )
    elements.push(
      textElement({
        left: left + 96,
        top: 466,
        width: 340,
        height: 100,
        content: step,
        fontSize: fitFont(step, 340, 100, 29, 23),
        color: palette.text,
        bold: true,
        lineHeight: 1.3
      })
    )
    if (index < steps.length - 1) elements.push(lineElement(left + 452, 492, left + 478, 492, palette.muted))
  })
  addClassroomCue(elements, page, palette)
  return elements
}

function activityTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "课堂活动")
  const task = activityTask(page) || studentHeadline(page) || "一起完成课堂挑战"
  if (!sameVisibleText(task, page.title)) {
    elements.push(
      textElement({
        left: 92,
        top: 190,
        width: 1400,
        height: 90,
        content: task,
        fontSize: fitFont(task, 1400, 90, 42, 30),
        color: palette.primary,
        bold: true
      })
    )
  }
  elements.push(...storySequence(activitySteps(page, 4), palette, 92, 360, 1416))
  addClassroomCue(elements, page, palette)
  return elements
}

function performanceTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "合作表现")
  const task = activityTask(page) || studentHeadline(page) || "一起完成音乐表演"
  if (!sameVisibleText(task, page.title)) {
    elements.push(shapeElement({ left: 92, top: 200, width: 1416, height: 150, fill: palette.primary, radius: 8 }))
    elements.push(
      textElement({
        left: 150,
        top: 242,
        width: 1300,
        height: 70,
        content: task,
        fontSize: fitFont(task, 1300, 70, 42, 30),
        color: "#FFFFFF",
        bold: true
      })
    )
  }
  const steps = activitySteps(page, 4)
  steps.forEach((step, index) => {
    const left = 126 + index * 355
    elements.push(shapeElement({ left, top: 438, width: 76, height: 76, fill: index % 2 ? palette.secondary : palette.accent, radius: 38 }))
    elements.push(
      textElement({ left: left + 23, top: 454, width: 34, height: 38, content: `${index + 1}`, fontSize: 28, color: "#FFFFFF", bold: true })
    )
    elements.push(
      textElement({
        left: left - 16,
        top: 550,
        width: 280,
        height: 100,
        content: step,
        fontSize: fitFont(step, 280, 100, 29, 22),
        color: palette.text,
        bold: true
      })
    )
    if (index < steps.length - 1) elements.push(lineElement(left + 96, 476, left + 325, 476, palette.muted, 3))
  })
  addClassroomCue(elements, page, palette)
  return elements
}

function practiceTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "课堂检测")
  const candidate = page.interaction?.question || studentHeadline(page) || activityTask(page) || "你能完成今天的音乐挑战吗？"
  const question = sameVisibleText(candidate, page.title) ? "" : candidate
  if (question)
    elements.push(
      textElement({
        left: 92,
        top: 200,
        width: 1416,
        height: 82,
        content: question,
        fontSize: fitFont(question, 1416, 82, 42, 30),
        color: palette.text,
        bold: true
      })
    )
  const options = validInteractionOptions(page)
  const items = options.length >= 2 ? options : studentPoints(page, 3)
  items.forEach((point, index) => {
    const top = 330 + index * 94
    elements.push(shapeElement({ left: 110, top, width: 70, height: 62, fill: index % 2 ? palette.secondary : palette.primary, radius: 8 }))
    elements.push(
      textElement({
        left: 132,
        top: top + 14,
        width: 32,
        height: 34,
        content: String.fromCharCode(65 + index),
        fontSize: 26,
        color: "#FFFFFF",
        bold: true
      })
    )
    elements.push(
      textElement({
        left: 220,
        top: top + 4,
        width: 1220,
        height: 58,
        content: point,
        fontSize: fitFont(point, 1220, 58, 31, 24),
        color: palette.text,
        bold: true
      })
    )
    elements.push(lineElement(220, top + 72, 1450, top + 72, palette.soft, 2))
  })
  addClassroomCue(elements, page, palette)
  return elements
}

function summaryTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "课堂小结")
  studentPoints(page, 4).forEach((point, index) => {
    const top = 220 + index * 112
    const color = index % 2 === 0 ? palette.secondary : palette.primary
    elements.push(shapeElement({ left: 100, top, width: 62, height: 62, fill: color, radius: 8 }))
    elements.push(textElement({ left: 118, top: top + 12, width: 30, height: 30, content: "✓", fontSize: 28, color: "#FFFFFF", bold: true }))
    elements.push(
      textElement({
        left: 210,
        top: top + 4,
        width: 1240,
        height: 64,
        content: point,
        fontSize: fitFont(point, 1240, 64, 34, 26),
        color: palette.text,
        bold: true
      })
    )
  })
  return elements
}

function homeworkTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const elements = slideHeader(page, outline, palette, "课后延伸")
  elements.push(shapeElement({ left: 92, top: 210, width: 1416, height: 440, fill: palette.surface, radius: 8, shadow: softShadow() }))
  activitySteps(page, 4).forEach((step, index) => {
    const top = 270 + index * 86
    elements.push(textElement({ left: 150, top, width: 70, height: 48, content: `${index + 1}.`, fontSize: 34, color: palette.accent, bold: true }))
    elements.push(
      textElement({
        left: 230,
        top,
        width: 1180,
        height: 58,
        content: step,
        fontSize: fitFont(step, 1180, 58, 31, 24),
        color: palette.text,
        bold: true
      })
    )
  })
  return elements
}

function contentTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette, index: number): PPTElement[] {
  return knowledgeTemplate(page, outline, palette, index)
}

function slideHeader(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette, eyebrow: string): PPTElement[] {
  const title = displayPageTitle(page, outline)
  return [
    textElement({ left: 92, top: 64, width: 300, height: 34, content: eyebrow, fontSize: 20, color: palette.secondary, bold: true }),
    textElement({
      left: 92,
      top: 102,
      width: 1320,
      height: 66,
      content: title,
      fontSize: fitFont(title, 1320, 66, 42, 32),
      color: palette.text,
      bold: true
    }),
    shapeElement({ left: 1450, top: 72, width: 58, height: 8, fill: palette.accent, radius: 4 })
  ]
}

function studentPanel(page: AiCoursewarePage, palette: Palette, left: number, top: number, width: number): PPTElement[] {
  const elements: PPTElement[] = []
  const headline = studentHeadline(page)
  if (headline)
    elements.push(
      textElement({
        left,
        top,
        width,
        height: 90,
        content: headline,
        fontSize: fitFont(headline, width, 90, 36, 27),
        color: palette.primary,
        bold: true
      })
    )
  studentPoints(page, 3).forEach((point, index) => {
    const itemTop = top + (headline ? 120 : 0) + index * 74
    elements.push(shapeElement({ left, top: itemTop + 8, width: 18, height: 18, fill: index % 2 ? palette.secondary : palette.accent, radius: 4 }))
    elements.push(
      textElement({
        left: left + 38,
        top: itemTop,
        width: width - 38,
        height: 54,
        content: point,
        fontSize: fitFont(point, width - 38, 54, 27, 21),
        color: palette.text,
        lineHeight: 1.3
      })
    )
  })
  return elements
}

function storySequence(items: string[], palette: Palette, left: number, top: number, width: number): PPTElement[] {
  const elements: PPTElement[] = []
  const count = Math.max(1, Math.min(items.length, 4))
  const gap = 28
  const cardWidth = (width - gap * (count - 1)) / count
  items.slice(0, 4).forEach((item, index) => {
    const cardLeft = left + index * (cardWidth + gap)
    elements.push(
      shapeElement({
        left: cardLeft,
        top,
        width: cardWidth,
        height: 190,
        fill: index % 2 === 0 ? palette.soft : palette.surface,
        radius: 8,
        shadow: lightShadow()
      })
    )
    elements.push(
      textElement({
        left: cardLeft + 24,
        top: top + 24,
        width: 64,
        height: 38,
        content: `0${index + 1}`,
        fontSize: 26,
        color: index % 2 === 0 ? palette.primary : palette.secondary,
        bold: true
      })
    )
    elements.push(
      textElement({
        left: cardLeft + 24,
        top: top + 82,
        width: cardWidth - 48,
        height: 78,
        content: item,
        fontSize: fitFont(item, cardWidth - 48, 78, 27, 21),
        color: palette.text,
        bold: true,
        lineHeight: 1.3
      })
    )
  })
  return elements
}

function knowledgeList(items: string[], palette: Palette, left: number, top: number, width: number): PPTElement[] {
  const elements: PPTElement[] = []
  items.forEach((item, index) => {
    const itemTop = top + index * 108
    elements.push(
      shapeElement({
        left,
        top: itemTop,
        width,
        height: 82,
        fill: index % 2 === 0 ? palette.surface : palette.soft,
        radius: 8,
        shadow: lightShadow()
      })
    )
    elements.push(shapeElement({ left, top: itemTop, width: 14, height: 82, fill: index % 2 === 0 ? palette.primary : palette.secondary, radius: 0 }))
    elements.push(
      textElement({
        left: left + 42,
        top: itemTop + 18,
        width: width - 74,
        height: 48,
        content: item,
        fontSize: fitFont(item, width - 74, 48, 29, 22),
        color: palette.text,
        bold: true
      })
    )
  })
  return elements
}

function addClassroomCue(elements: PPTElement[], page: AiCoursewarePage, palette: Palette) {
  // 保留调用点以兼容既有模板；课堂任务由页面主体呈现，不再生成重复底栏。
  void elements
  void page
  void palette
}

function dedicatedResourceElement(page: AiCoursewarePage): PPTElement | undefined {
  const binding = (page.resourceBindings || []).find(item => item.verified !== false && item.dedicatedPage)
  if (!binding || binding.resourceType !== "MUSIC") return undefined
  const base = { id: nanoid(10), left: 0, top: 0, width: SLIDE_WIDTH, height: SLIDE_HEIGHT, rotate: 0 }
  return { ...base, type: "elf", subtype: "elf-sing-play", sid: binding.resourceId, title: binding.name || page.title } as PPTCloudCoachElement
}

function inlineResourceElements(page: AiCoursewarePage): PPTElement[] {
  const binding = (page.resourceBindings || []).find(item => item.verified !== false && item.resourceType === "SONG" && item.contentUrl)
  if (!binding) return []
  return [
    {
      id: nanoid(10),
      type: "elf",
      subtype: "elf-enjoy",
      left: 110,
      top: 700,
      width: 1380,
      height: 100,
      rotate: 0,
      sid: binding.resourceId,
      title: binding.name || page.title,
      src: binding.contentUrl || "",
      enjoyList: [{ id: binding.resourceId, title: binding.name || page.title, src: binding.contentUrl || "" }]
    } as PPTEnjoyElement
  ]
}

function videoBinding(page: AiCoursewarePage) {
  return (page.resourceBindings || []).find(item => item.verified !== false && item.resourceType === "VIDEO" && item.contentUrl)
}

function videoResourceTemplate(page: AiCoursewarePage, outline: AiCoursewareOutline, palette: Palette): PPTElement[] {
  const binding = videoBinding(page)!
  const elements = slideHeader(page, outline, palette, page.teachingStage || "观看与发现")
  elements.push({
    id: nanoid(10),
    type: "elf",
    subtype: "elf-video",
    left: 190,
    top: 190,
    width: 1220,
    height: 570,
    rotate: 0,
    src: binding.contentUrl || "",
    poster: binding.coverUrl,
    autoplay: false
  } as PPTVideoElement)
  addClassroomCue(elements, page, palette)
  return elements
}

function normalizeOutline(outline: AiCoursewareOutline): AiCoursewareOutline {
  const chapter = cleanText(outline.chapterName || outline.title || "音乐课件")
  return {
    ...outline,
    title: GENERIC_PAGE_TITLES.has(cleanText(outline.title).toLowerCase()) ? chapter : cleanText(outline.title || chapter),
    pages: (outline.pages || []).map((page, index) => ({
      ...page,
      pageNo: index + 1,
      title: index === 0 && GENERIC_PAGE_TITLES.has(cleanText(page.title).toLowerCase()) ? chapter : cleanText(page.title || chapter),
      bullets: (page.bullets || []).map(cleanText).filter(Boolean),
      imageKeywords: (page.imageKeywords || []).map(cleanText).filter(Boolean)
    }))
  }
}

function pageRole(page: AiCoursewarePage, index: number): PageRole {
  if (index === 0) return "cover"
  const kind = `${page.type || ""} ${page.visualPlan?.layout || ""} ${page.visual?.layout || ""}`.toLowerCase()
  if (kind.includes("objective") || kind.includes("goal")) return "goal"
  if (kind.includes("practice_check") || kind.includes("assessment")) return "practice"
  if (kind.includes("compare")) return "compare"
  if (kind.includes("instrument")) return "instrument"
  if (kind.includes("melody") || kind.includes("score") || kind.includes("notation")) return "notation"
  if (kind.includes("performance") || kind.includes("expressive") || kind.includes("creative")) return "performance"
  if (kind.includes("listen")) return "listen"
  if (kind.includes("lyric") || kind.includes("phrase_sing") || kind.includes("sing_focus")) return "lyric"
  if (kind.includes("rhythm") || kind.includes("skill")) return "rhythm"
  if (kind.includes("knowledge")) return "knowledge"
  if (kind.includes("interaction")) return "interaction"
  if (kind.includes("activity")) return "activity"
  if (kind.includes("summary")) return "summary"
  if (kind.includes("homework") || kind.includes("extension")) return "homework"
  if (kind.includes("intro") || kind.includes("scene")) return "intro"
  if (kind.includes("context") || kind.includes("background") || kind.includes("story")) return "story"
  return "content"
}

function displayPageTitle(page: AiCoursewarePage, outline: AiCoursewareOutline) {
  const title = cleanText(page.title)
  return !title || GENERIC_PAGE_TITLES.has(title.toLowerCase()) ? chapterTitle(outline, page) : title
}

function chapterTitle(outline: AiCoursewareOutline, page: AiCoursewarePage) {
  return cleanText(outline.chapterName || outline.title || page.title || "音乐课件")
}

function conciseTextbook(value?: string) {
  return cleanText(value).replace(/^.*?·/, "")
}

function hasImage(page: AiCoursewarePage) {
  return Boolean(page.image?.url)
}

function studentHeadline(page: AiCoursewarePage) {
  const headline = cleanText(page.studentContent?.headline || page.subtitle || "")
  return sameVisibleText(headline, page.title) ? "" : headline
}

function studentPoints(page: AiCoursewarePage, limit: number) {
  const structured = (page.studentContent?.points || []).map(cleanText).filter(Boolean)
  const legacy = (page.bullets || []).map(cleanText).filter(Boolean)
  const points = structured.length ? structured : legacy
  const excluded = [page.title, studentHeadline(page)].map(normalizeVisibleText).filter(Boolean)
  const unique = uniqueVisibleTexts(points).filter(item => !excluded.includes(normalizeVisibleText(item)))
  return (unique.length ? unique : [studentHeadline(page) || cleanText(page.title) || "课堂内容"]).slice(0, limit)
}

function activityTask(page: AiCoursewarePage) {
  // activity 属于教师组织信息，不能回退到学生投屏画面。
  return cleanText(page.classroomAction?.studentTask || studentHeadline(page) || "")
}

function activitySteps(page: AiCoursewarePage, limit: number) {
  const task = activityTask(page)
  const points = studentPoints(page, limit).filter(item => !sameVisibleText(item, task))
  return uniqueVisibleTexts(points).slice(0, limit)
}

function validInteractionOptions(page: AiCoursewarePage) {
  return uniqueVisibleTexts((page.interaction?.options || []).map(cleanText).filter(Boolean))
    .filter(item => !/^(?:准备好了吗|开始吧|请回答|想一想|说一说|听一听)[？?!！。]*$/.test(item))
    .slice(0, 4)
}

function slideRemark(page: AiCoursewarePage) {
  const lessonMeta = [page.teachingStage, page.durationMinutes ? `建议用时：${page.durationMinutes}分钟` : ""].filter(Boolean).join(" · ")
  const evidence = page.learningEvidence ? `学习表现：${page.learningEvidence}` : ""
  const activity = [page.activity?.task, ...(page.activity?.steps || [])].map(cleanText).filter(Boolean).join("\n")
  return [lessonMeta, page.teachingPurpose, activity, page.speakerNotes, page.teacherTips, page.classroomAction?.teacherInstruction, evidence]
    .map(cleanText)
    .filter(Boolean)
    .filter((item, index, all) => all.indexOf(item) === index)
    .join("\n")
}

function buildPalette(outline: AiCoursewareOutline, variant: number, templateId?: AiCoursewareTemplateId): Palette {
  const fallbackTemplate = outline.style === "cartoon" ? "playful-handdrawn" : "fresh-education"
  return { ...getAiCoursewarePalette(templateId || fallbackTemplate, variant) }
}

function backgroundConfig(_role: PageRole, palette: Palette, options: AiPptOptions): SlideBackground {
  if (options.backgroundImage) return { type: "image", image: options.backgroundImage, imageSize: "cover" }
  return { type: "solid", color: palette.background }
}

function fitFont(content: string, width: number, height: number, preferred: number, minimum: number) {
  const text = cleanText(content)
  if (!text) return preferred
  let size = preferred
  while (size > minimum) {
    const charsPerLine = Math.max(1, Math.floor(width / size))
    const lines = Math.ceil(text.length / charsPerLine)
    if (lines * size * 1.35 <= height) break
    size -= 2
  }
  return size
}

function textElement(params: {
  left: number
  top: number
  width: number
  height: number
  content: string
  fontSize: number
  color: string
  bold?: boolean
  lineHeight?: number
}): PPTTextElement {
  const lineHeight = params.lineHeight || 1.25
  const minimum = Math.min(params.fontSize, params.fontSize >= 30 ? 22 : 18)
  const resolvedFontSize = fitFont(params.content, params.width - 20, params.height, params.fontSize, minimum)
  return {
    id: nanoid(10),
    type: "text",
    left: params.left,
    top: params.top,
    width: params.width,
    height: params.height,
    rotate: 0,
    // 永远保留完整文本。若最小字号仍放不下，由质量门禁阻止应用，而不是静默截断。
    content: `<div style="box-sizing:border-box;width:calc(100% - 20px);font-family:${FONT_NAME};font-size:${resolvedFontSize}px;${params.bold ? "font-weight:700;" : ""}">${escapeHtml(cleanText(params.content))}</div>`,
    defaultFontName: FONT_NAME,
    defaultColor: params.color,
    lineHeight,
    paragraphSpace: 0,
    wordSpace: 0,
    opacity: 1
  }
}

function imageElement(page: AiCoursewarePage, rect: ImageRect): PPTImageElement {
  const width = page.image?.width || 0
  const height = page.image?.height || 0
  return {
    id: nanoid(10),
    type: "image",
    left: rect.left,
    top: rect.top,
    width: rect.width,
    height: rect.height,
    rotate: 0,
    src: page.image?.url || "",
    fixedRatio: false,
    radius: rect.radius || 0,
    shadow: rect.radius ? softShadow() : undefined,
    clip: width > 0 && height > 0 ? { shape: "rect", range: coverRange(width, height, rect.width, rect.height) } : undefined
  }
}

function coverRange(sourceWidth: number, sourceHeight: number, targetWidth: number, targetHeight: number): [[number, number], [number, number]] {
  const sourceRatio = sourceWidth / sourceHeight
  const targetRatio = targetWidth / targetHeight
  if (sourceRatio > targetRatio) {
    const visible = (targetRatio / sourceRatio) * 100
    const start = (100 - visible) / 2
    return [
      [start, 0],
      [100 - start, 100]
    ]
  }
  const visible = (sourceRatio / targetRatio) * 100
  const start = (100 - visible) / 2
  return [
    [0, start],
    [100, 100 - start]
  ]
}

function shapeElement(params: {
  left: number
  top: number
  width: number
  height: number
  fill: string
  opacity?: number
  radius?: number
  shadow?: PPTElementShadow
  gradient?: Gradient
  text?: PPTShapeElement["text"]
}): PPTShapeElement {
  return {
    id: nanoid(10),
    type: "shape",
    left: params.left,
    top: params.top,
    width: params.width,
    height: params.height,
    rotate: 0,
    viewBox: [200, 200],
    path: roundedRectPath(params.radius || 0),
    fixedRatio: false,
    fill: params.fill,
    opacity: params.opacity ?? 1,
    shadow: params.shadow,
    gradient: params.gradient,
    text: params.text
  }
}

function lineElement(x1: number, y1: number, x2: number, y2: number, color: string, width = 2): PPTLineElement {
  const left = Math.min(x1, x2)
  const top = Math.min(y1, y2)
  const lineWidth = Math.abs(x2 - x1)
  const lineHeight = Math.abs(y2 - y1)
  return {
    id: nanoid(10),
    type: "line",
    left,
    top,
    width,
    start: [x1 === left ? 0 : lineWidth, y1 === top ? 0 : lineHeight],
    end: [x2 === left ? 0 : lineWidth, y2 === top ? 0 : lineHeight],
    style: "solid",
    color,
    points: ["", ""]
  }
}

function keepInCanvas(elements: PPTElement[]) {
  return elements.map(element => {
    const left = Math.max(0, Math.min(element.left, SLIDE_WIDTH - 1))
    const top = Math.max(0, Math.min(element.top, SLIDE_HEIGHT - 1))
    if (element.type === "line") return { ...element, left, top, width: Math.max(1, Math.min(element.width, 20)) }
    return {
      ...element,
      left,
      top,
      width: Math.max(1, Math.min(element.width, SLIDE_WIDTH - left)),
      height: Math.max(1, Math.min(element.height, SLIDE_HEIGHT - top))
    }
  }) as PPTElement[]
}

function scaleElementsToViewport(elements: PPTElement[]): PPTElement[] {
  return elements.map(element => {
    if (element.type === "line") {
      return {
        ...element,
        left: element.left * VIEWPORT_SCALE,
        top: element.top * VIEWPORT_SCALE,
        width: element.width * VIEWPORT_SCALE,
        start: [element.start[0] * VIEWPORT_SCALE, element.start[1] * VIEWPORT_SCALE],
        end: [element.end[0] * VIEWPORT_SCALE, element.end[1] * VIEWPORT_SCALE]
      }
    }

    const scaled = {
      ...element,
      left: element.left * VIEWPORT_SCALE,
      top: element.top * VIEWPORT_SCALE,
      width: element.width * VIEWPORT_SCALE,
      height: element.height * VIEWPORT_SCALE
    } as PPTElement
    if (scaled.type === "text") {
      scaled.content = scaleInlineFontSizes(scaled.content)
    }
    if (scaled.type === "shape" && scaled.text) {
      scaled.text = { ...scaled.text, content: scaleInlineFontSizes(scaled.text.content) }
    }
    if ("radius" in scaled && typeof scaled.radius === "number") {
      scaled.radius *= VIEWPORT_SCALE
    }
    if ("shadow" in scaled && scaled.shadow) {
      scaled.shadow = {
        ...scaled.shadow,
        h: scaled.shadow.h * VIEWPORT_SCALE,
        v: scaled.shadow.v * VIEWPORT_SCALE,
        blur: scaled.shadow.blur * VIEWPORT_SCALE
      }
    }
    return scaled
  })
}

function scaleInlineFontSizes(content: string) {
  return content.replace(/font-size:\s*([\d.]+)px/g, (_match, size) => `font-size:${Number(size) * VIEWPORT_SCALE}px`)
}

function runPreflight(slides: Slide[]) {
  slides.forEach((slide, index) => {
    const invalid = slide.elements.filter(
      element =>
        element.left < 0 ||
        element.top < 0 ||
        element.left + element.width > VIEWPORT_WIDTH + 1 ||
        (element.type !== "line" && element.top + element.height > VIEWPORT_HEIGHT + 1)
    )
    const emptyText = slide.elements.filter(element => element.type === "text" && !stripHtml(element.content))
    if (invalid.length || emptyText.length)
      console.warn("AI PPT preflight issue", { pageNo: index + 1, invalid: invalid.length, emptyText: emptyText.length })
  })
}

function roundedRectPath(radius: number) {
  const r = Math.max(0, Math.min(radius, 100))
  return `M ${r} 0 L ${200 - r} 0 Q 200 0 200 ${r} L 200 ${200 - r} Q 200 200 ${200 - r} 200 L ${r} 200 Q 0 200 0 ${200 - r} L 0 ${r} Q 0 0 ${r} 0 Z`
}

function softShadow(): PPTElementShadow {
  return { h: 0, v: 8, blur: 22, color: "rgba(23, 34, 46, 0.14)" }
}

function lightShadow(): PPTElementShadow {
  return { h: 0, v: 4, blur: 14, color: "rgba(23, 34, 46, 0.1)" }
}

function cleanText(value?: string) {
  return String(value || "")
    .replace(/\s+/g, " ")
    .trim()
}

function escapeHtml(value: string) {
  return cleanText(value).replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;")
}

function stripHtml(value: string) {
  return value.replace(/<[^>]+>/g, "").trim()
}

function normalizeVisibleText(value?: string) {
  return cleanText(value)
    .replace(/[，。！？、；：,.!?;:\s]+/g, "")
    .toLowerCase()
}

function sameVisibleText(left?: string, right?: string) {
  const normalizedLeft = normalizeVisibleText(left)
  return Boolean(normalizedLeft) && normalizedLeft === normalizeVisibleText(right)
}

function uniqueVisibleTexts(values: string[]) {
  const seen = new Set<string>()
  return values.filter(value => {
    const key = normalizeVisibleText(value)
    if (!key || seen.has(key)) return false
    seen.add(key)
    return true
  })
}