import html2canvas from "html2canvas"
import { toPng, toJpeg, toBlob, toSvg } from "html-to-image"

export interface ScreenshotOptions {
  format?: "png" | "jpeg" | "webp" | "svg"
  quality?: number
  width?: number
  height?: number
  scale?: number
  backgroundColor?: string
  skipFonts?: boolean
  preferredFontFormat?: string
  timeout?: number
}

export interface ScreenshotResult {
  success: boolean
  dataUrl?: string
  blob?: Blob
  error?: string
  method?: string
}

class EnhancedScreenshotService {
  private retryCount = 3
  private retryDelay = 1000

  async captureElement(element: HTMLElement, options: ScreenshotOptions = {}): Promise<ScreenshotResult> {
    const methods = [
      () => this.captureWithHtmlToImage(element, options),
      () => this.captureWithHtml2Canvas(element, options),
      () => this.captureWithCanvas(element, options),
      () => this.captureWithSVG(element, options),
    ]

    for (const method of methods) {
      for (let attempt = 0; attempt < this.retryCount; attempt++) {
        try {
          const result = await method()
          if (result.success) {
            return result
          }
        } catch (error) {
          console.warn(`截图方法失败 (尝试 ${attempt + 1}):`, error)
          if (attempt < this.retryCount - 1) {
            await this.delay(this.retryDelay)
          }
        }
      }
    }

    return {
      success: false,
      error: "所有截图方法都失败了",
    }
  }

  private async captureWithHtmlToImage(element: HTMLElement, options: ScreenshotOptions): Promise<ScreenshotResult> {
    try {
      // 等待字体和图片加载
      await this.waitForAssets(element)

      const config = {
        quality: options.quality || 0.95,
        width: options.width,
        height: options.height,
        backgroundColor: options.backgroundColor || "#ffffff",
        skipFonts: options.skipFonts || false,
        preferredFontFormat: options.preferredFontFormat || "woff2",
        pixelRatio: options.scale || window.devicePixelRatio || 1,
        cacheBust: true,
        useCORS: true,
        allowTaint: true,
        style: {
          transform: "scale(1)",
          transformOrigin: "top left",
        },
      }

      let dataUrl: string
      let blob: Blob | undefined

      switch (options.format) {
        case "jpeg":
          dataUrl = await toJpeg(element, config)
          blob = await toBlob(element, config)
          break
        case "svg":
          dataUrl = await toSvg(element, config)
          break
        default:
          dataUrl = await toPng(element, config)
          blob = await toBlob(element, config)
      }

      return {
        success: true,
        dataUrl,
        blob,
        method: "html-to-image",
      }
    } catch (error) {
      throw new Error(`html-to-image 截图失败: ${error}`)
    }
  }

  private async captureWithHtml2Canvas(element: HTMLElement, options: ScreenshotOptions): Promise<ScreenshotResult> {
    try {
      await this.waitForAssets(element)

      const canvas = await html2canvas(element, {
        allowTaint: true,
        useCORS: true,
        scale: options.scale || window.devicePixelRatio || 1,
        width: options.width,
        height: options.height,
        backgroundColor: options.backgroundColor || "#ffffff",
        logging: false,
        removeContainer: true,
        imageTimeout: options.timeout || 15000,
        onclone: (clonedDoc) => {
          // 确保克隆的文档样式正确
          const clonedElement = clonedDoc.querySelector(`[data-screenshot-target]`)
          if (clonedElement) {
            clonedElement.style.transform = "none"
            clonedElement.style.position = "static"
          }
        },
      })

      const dataUrl = canvas.toDataURL(`image/${options.format || "png"}`, options.quality || 0.95)

      return new Promise((resolve) => {
        canvas.toBlob(
          (blob) => {
            resolve({
              success: true,
              dataUrl,
              blob: blob || undefined,
              method: "html2canvas",
            })
          },
          `image/${options.format || "png"}`,
          options.quality || 0.95,
        )
      })
    } catch (error) {
      throw new Error(`html2canvas 截图失败: ${error}`)
    }
  }

  private async captureWithCanvas(element: HTMLElement, options: ScreenshotOptions): Promise<ScreenshotResult> {
    try {
      const rect = element.getBoundingClientRect()
      const canvas = document.createElement("canvas")
      const ctx = canvas.getContext("2d")

      if (!ctx) {
        throw new Error("无法获取Canvas上下文")
      }

      const scale = options.scale || window.devicePixelRatio || 1
      canvas.width = (options.width || rect.width) * scale
      canvas.height = (options.height || rect.height) * scale

      ctx.scale(scale, scale)
      ctx.fillStyle = options.backgroundColor || "#ffffff"
      ctx.fillRect(0, 0, canvas.width / scale, canvas.height / scale)

      // 使用SVG foreignObject来渲染HTML
      const svgData = await this.elementToSVG(element)
      const img = new Image()

      return new Promise((resolve, reject) => {
        img.onload = () => {
          ctx.drawImage(img, 0, 0)
          const dataUrl = canvas.toDataURL(`image/${options.format || "png"}`, options.quality || 0.95)

          canvas.toBlob(
            (blob) => {
              resolve({
                success: true,
                dataUrl,
                blob: blob || undefined,
                method: "canvas",
              })
            },
            `image/${options.format || "png"}`,
            options.quality || 0.95,
          )
        }

        img.onerror = () => reject(new Error("图片加载失败"))
        img.src = `data:image/svg+xml;base64,${btoa(svgData)}`
      })
    } catch (error) {
      throw new Error(`Canvas 截图失败: ${error}`)
    }
  }

  private async captureWithSVG(element: HTMLElement, options: ScreenshotOptions): Promise<ScreenshotResult> {
    try {
      const svgData = await this.elementToSVG(element)
      const dataUrl = `data:image/svg+xml;base64,${btoa(svgData)}`

      if (options.format === "svg") {
        return {
          success: true,
          dataUrl,
          method: "svg",
        }
      }

      // 转换SVG为其他格式
      const canvas = document.createElement("canvas")
      const ctx = canvas.getContext("2d")

      if (!ctx) {
        throw new Error("无法获取Canvas上下文")
      }

      const img = new Image()

      return new Promise((resolve, reject) => {
        img.onload = () => {
          const scale = options.scale || 1
          canvas.width = (options.width || img.width) * scale
          canvas.height = (options.height || img.height) * scale

          ctx.scale(scale, scale)
          ctx.fillStyle = options.backgroundColor || "#ffffff"
          ctx.fillRect(0, 0, canvas.width / scale, canvas.height / scale)
          ctx.drawImage(img, 0, 0)

          const finalDataUrl = canvas.toDataURL(`image/${options.format || "png"}`, options.quality || 0.95)

          canvas.toBlob(
            (blob) => {
              resolve({
                success: true,
                dataUrl: finalDataUrl,
                blob: blob || undefined,
                method: "svg-to-canvas",
              })
            },
            `image/${options.format || "png"}`,
            options.quality || 0.95,
          )
        }

        img.onerror = () => reject(new Error("SVG转换失败"))
        img.src = dataUrl
      })
    } catch (error) {
      throw new Error(`SVG 截图失败: ${error}`)
    }
  }

  private async elementToSVG(element: HTMLElement): Promise<string> {
    const rect = element.getBoundingClientRect()
    const computedStyle = window.getComputedStyle(element)

    // 获取所有样式
    const styles = this.getAllStyles()

    const svg = `
      <svg xmlns="http://www.w3.org/2000/svg" 
           width="${rect.width}" 
           height="${rect.height}">
        <defs>
          <style type="text/css">
            <![CDATA[
              ${styles}
            ]]>
          </style>
        </defs>
        <foreignObject width="100%" height="100%">
          <div xmlns="http://www.w3.org/1999/xhtml">
            ${element.outerHTML}
          </div>
        </foreignObject>
      </svg>
    `

    return svg
  }

  private getAllStyles(): string {
    let styles = ""

    // 获取所有样式表
    for (let i = 0; i < document.styleSheets.length; i++) {
      try {
        const styleSheet = document.styleSheets[i]
        if (styleSheet.cssRules) {
          for (let j = 0; j < styleSheet.cssRules.length; j++) {
            styles += styleSheet.cssRules[j].cssText + "\n"
          }
        }
      } catch (e) {
        // 跨域样式表可能无法访问
        console.warn("无法访问样式表:", e)
      }
    }

    return styles
  }

  private async waitForAssets(element: HTMLElement): Promise<void> {
    const images = element.querySelectorAll("img")
    const promises: Promise<void>[] = []

    images.forEach((img) => {
      if (!img.complete) {
        promises.push(
          new Promise((resolve) => {
            img.onload = () => resolve()
            img.onerror = () => resolve() // 即使加载失败也继续
            setTimeout(() => resolve(), 5000) // 5秒超时
          }),
        )
      }
    })

    // 等待字体加载
    if (document.fonts) {
      promises.push(document.fonts.ready.catch(() => {}))
    }

    await Promise.all(promises)

    // 额外等待确保渲染完成
    await this.delay(500)
  }

  private delay(ms: number): Promise<void> {
    return new Promise((resolve) => setTimeout(resolve, ms))
  }

  async captureFullPage(options: ScreenshotOptions = {}): Promise<ScreenshotResult> {
    try {
      // 标记body元素用于截图
      document.body.setAttribute("data-screenshot-target", "true")

      const result = await this.captureElement(document.body, {
        ...options,
        width: window.innerWidth,
        height: document.body.scrollHeight,
      })

      document.body.removeAttribute("data-screenshot-target")
      return result
    } catch (error) {
      document.body.removeAttribute("data-screenshot-target")
      throw error
    }
  }

  async captureViewport(options: ScreenshotOptions = {}): Promise<ScreenshotResult> {
    try {
      // 创建一个包含当前视口的容器
      const viewport = document.createElement("div")
      viewport.style.position = "fixed"
      viewport.style.top = "0"
      viewport.style.left = "0"
      viewport.style.width = "100vw"
      viewport.style.height = "100vh"
      viewport.style.pointerEvents = "none"
      viewport.style.zIndex = "9999"

      // 克隆当前视口内容
      const bodyClone = document.body.cloneNode(true) as HTMLElement
      viewport.appendChild(bodyClone)
      document.body.appendChild(viewport)

      const result = await this.captureElement(viewport, {
        ...options,
        width: window.innerWidth,
        height: window.innerHeight,
      })

      document.body.removeChild(viewport)
      return result
    } catch (error) {
      throw new Error(`视口截图失败: ${error}`)
    }
  }
}

export const enhancedScreenshotService = new EnhancedScreenshotService()