import {
  Document,
  HeadingLevel,
  ImageRun,
  Packer,
  Paragraph,
  TableOfContents,
  TextRun,
  AlignmentType,
  PageBreak,
  BorderStyle,
} from "docx"
import type { DocumentationPage } from "@/lib/documentation/catalog"

export type DocumentationRenderItem = {
  page: DocumentationPage
  screenshotPng?: Buffer
  error?: string
}

function groupBy<T>(items: T[], getKey: (item: T) => string): Record<string, T[]> {
  const map: Record<string, T[]> = {}
  for (const item of items) {
    const key = getKey(item)
    if (!map[key]) map[key] = []
    map[key].push(item)
  }
  return map
}

export async function renderDocumentationDocx(items: DocumentationRenderItem[]) {
  const now = new Date()
  const title = "Soul派对 - 应用功能文档"
  const subtitle = `生成时间：${now.toLocaleString("zh-CN", { hour12: false })}`
  const version = `文档版本：v1.0`

  const children: Paragraph[] = []

  children.push(new Paragraph({ text: "" }))
  children.push(new Paragraph({ text: "" }))
  children.push(
    new Paragraph({
      text: title,
      heading: HeadingLevel.TITLE,
      alignment: AlignmentType.CENTER,
    }),
  )
  children.push(
    new Paragraph({
      children: [new TextRun({ text: subtitle, size: 24 })],
      alignment: AlignmentType.CENTER,
    }),
  )
  children.push(
    new Paragraph({
      children: [new TextRun({ text: version, size: 20, color: "666666" })],
      alignment: AlignmentType.CENTER,
    }),
  )
  children.push(new Paragraph({ text: "" }))
  children.push(new Paragraph({ text: "" }))

  children.push(
    new Paragraph({
      text: "文档概述",
      heading: HeadingLevel.HEADING_1,
    }),
  )
  children.push(
    new Paragraph({
      children: [
        new TextRun({
          text: "本文档自动生成，包含应用程序所有核心页面的功能说明与界面截图。文档按功能模块分组，便于快速查阅和理解应用结构。",
        }),
      ],
    }),
  )
  children.push(
    new Paragraph({
      children: [
        new TextRun({
          text: `共包含 ${items.length} 个页面，${Object.keys(groupBy(items, (i) => i.page.group)).length} 个功能模块。`,
        }),
      ],
    }),
  )
  children.push(new Paragraph({ text: "" }))

  children.push(
    new Paragraph({
      text: "目录",
      heading: HeadingLevel.HEADING_1,
    }),
  )
  children.push(
    new TableOfContents("目录", {
      hyperlink: true,
      headingStyleRange: "1-3",
    }),
  )
  children.push(
    new Paragraph({
      children: [new PageBreak()],
    }),
  )

  const grouped = groupBy(items, (i) => i.page.group)
  const groupNames = Object.keys(grouped)

  let pageNumber = 1
  for (const groupName of groupNames) {
    children.push(
      new Paragraph({
        text: groupName,
        heading: HeadingLevel.HEADING_1,
        border: {
          bottom: { color: "2DD4BF", size: 6, style: BorderStyle.SINGLE },
        },
      }),
    )
    children.push(new Paragraph({ text: "" }))

    for (const item of grouped[groupName]) {
      const { page } = item

      children.push(
        new Paragraph({
          text: `${pageNumber}. ${page.title}`,
          heading: HeadingLevel.HEADING_2,
        }),
      )

      if (page.subtitle) {
        children.push(
          new Paragraph({
            children: [new TextRun({ text: page.subtitle, italics: true, color: "666666" })],
          }),
        )
      }

      children.push(
        new Paragraph({
          children: [
            new TextRun({ text: "页面路径：", bold: true }),
            new TextRun({ text: page.path, color: "2563EB" }),
          ],
        }),
      )

      if (page.caption) {
        children.push(new Paragraph({ text: "" }))
        children.push(
          new Paragraph({
            children: [new TextRun({ text: "功能说明：", bold: true })],
          }),
        )
        children.push(
          new Paragraph({
            children: [new TextRun({ text: page.caption })],
          }),
        )
      }

      children.push(new Paragraph({ text: "" }))

      if (item.error) {
        children.push(
          new Paragraph({
            children: [
              new TextRun({ text: "截图状态：", bold: true }),
              new TextRun({ text: `失败 - ${item.error}`, color: "DC2626" }),
            ],
          }),
        )
      } else if (item.screenshotPng) {
        children.push(
          new Paragraph({
            children: [new TextRun({ text: "界面截图：", bold: true })],
          }),
        )
        children.push(new Paragraph({ text: "" }))
        children.push(
          new Paragraph({
            children: [
              new ImageRun({
                data: item.screenshotPng,
                transformation: { width: 320, height: 693 },
              }),
            ],
            alignment: AlignmentType.CENTER,
          }),
        )
        children.push(
          new Paragraph({
            children: [new TextRun({ text: `图${pageNumber}: ${page.title}界面`, size: 20, color: "666666" })],
            alignment: AlignmentType.CENTER,
          }),
        )
      }

      children.push(new Paragraph({ text: "" }))
      children.push(new Paragraph({ text: "" }))
      pageNumber++
    }

    children.push(
      new Paragraph({
        children: [new PageBreak()],
      }),
    )
  }

  children.push(
    new Paragraph({
      text: "附录",
      heading: HeadingLevel.HEADING_1,
    }),
  )
  children.push(
    new Paragraph({
      children: [new TextRun({ text: "技术说明", bold: true })],
    }),
  )
  children.push(
    new Paragraph({
      children: [
        new TextRun({
          text: "• 截图尺寸：430×932像素 (iPhone 14 Pro Max)",
        }),
      ],
    }),
  )
  children.push(
    new Paragraph({
      children: [
        new TextRun({
          text: "• 截图方式：Playwright自动化浏览器截图",
        }),
      ],
    }),
  )
  children.push(
    new Paragraph({
      children: [
        new TextRun({
          text: "• 文档格式：Microsoft Word (.docx)",
        }),
      ],
    }),
  )
  children.push(new Paragraph({ text: "" }))
  children.push(
    new Paragraph({
      children: [new TextRun({ text: "本文档由系统自动生成，如有问题请联系技术支持。", color: "666666", size: 20 })],
      alignment: AlignmentType.CENTER,
    }),
  )

  const doc = new Document({
    title: "Soul派对 - 应用功能文档",
    description: "自动生成的应用功能文档",
    creator: "Soul派对文档生成器",
    sections: [
      {
        properties: {},
        children,
      },
    ],
  })

  return await Packer.toBuffer(doc)
}