// 内容安全链路（微信平台规范）
//  文本：security.msgSecCheck v2（二维码内容 / 扫码导入内容 / 水印）
//  图片：先按官方建议压缩到 750×1334 内、1MB 内的 JPG，再上传云存储由云函数调用 security.imgSecCheck
// 约定返回：{ status: 'pass' | 'risky' | 'error' }
//  - risky：命中违规，必须拦截
//  - error：检测服务不可用，同样拦截（禁止静默放行）
// 通过结果按内容缓存，导出时无需重复请求，显著提升导出速度

const FUNCTION_NAME = 'quickstartFunctions'
const MAX_W = 750
const MAX_H = 1334
const textCache = new Map() // value -> 'pass' | 'risky'
const pending = new Map() // value -> Promise

function callFunction(data) {
  return new Promise((resolve) => {
    if (!wx.cloud) { resolve(null); return }
    wx.cloud.callFunction({
      name: FUNCTION_NAME,
      data,
      success: (res) => resolve((res && res.result) || null),
      fail: () => resolve(null),
    })
  })
}

function normalize(result) {
  if (!result) return 'error'
  if (result.risk) return 'risky'
  if (result.skipped) return 'error'
  return 'pass'
}

function checkText(content, scene = 2) {
  const value = String(content || '').trim().slice(0, 2500)
  if (!value) return Promise.resolve({ status: 'pass' })
  const cached = textCache.get(value)
  if (cached) return Promise.resolve({ status: cached, cached: true })
  if (pending.has(value)) return pending.get(value)
  const task = callFunction({ type: 'checkMessage', content: value, scene }).then((result) => {
    const status = normalize(result)
    if (status !== 'error') textCache.set(value, status)
    pending.delete(value)
    return { status }
  })
  pending.set(value, task)
  return task
}

// 导出前一次性校验多段文本（已缓存的直接复用，未缓存的合并为一次云函数调用）
function checkTexts(items) {
  const list = items.map((it) => ({ value: String(it.value || '').trim().slice(0, 2500), scene: it.scene || 2 })).filter((it) => it.value)
  const results = list.map((it) => textCache.get(it.value))
  if (results.includes('risky')) return Promise.resolve({ status: 'risky' })
  const missing = list.filter((it, i) => !results[i])
  if (!missing.length) return Promise.resolve({ status: 'pass' })
  return callFunction({ type: 'checkMessages', items: missing }).then((res) => {
    if (!res || !Array.isArray(res.results)) return { status: 'error' }
    let status = 'pass'
    res.results.forEach((r, i) => {
      const s = normalize(r)
      if (s !== 'error') textCache.set(missing[i].value, s)
      if (s === 'risky') status = 'risky'
      else if (s === 'error' && status === 'pass') status = 'error'
    })
    return { status }
  })
}

function isTextPassed(value) {
  const v = String(value || '').trim()
  return !v || textCache.get(v) === 'pass'
}

// 按官方尺寸建议压缩（同时加快上传）
function compressForCheck(canvas, image, path) {
  return new Promise((resolve) => {
    if (!canvas || !image) { resolve(path); return }
    try {
      const w0 = image.width || image._w
      const h0 = image.height || image._h
      const scale = Math.min(1, MAX_W / w0, MAX_H / h0)
      canvas.width = Math.max(1, Math.round(w0 * scale))
      canvas.height = Math.max(1, Math.round(h0 * scale))
      const ctx = canvas.getContext('2d')
      ctx.fillStyle = '#ffffff'
      ctx.fillRect(0, 0, canvas.width, canvas.height)
      ctx.drawImage(image, 0, 0, canvas.width, canvas.height)
      wx.canvasToTempFilePath({
        canvas,
        fileType: 'jpg',
        quality: 0.82,
        destWidth: canvas.width,
        destHeight: canvas.height,
        success: (res) => resolve(res.tempFilePath),
        fail: () => resolve(path),
      })
    } catch (e) {
      resolve(path)
    }
  })
}

function upload(filePath) {
  return new Promise((resolve) => {
    if (!wx.cloud) { resolve(''); return }
    wx.cloud.uploadFile({
      cloudPath: `sec-check/${Date.now()}-${Math.random().toString(36).slice(2, 10)}.jpg`,
      filePath,
      success: (res) => resolve((res && res.fileID) || ''),
      fail: () => resolve(''),
    })
  })
}

// image：已加载的 CanvasImage（用于压缩）；path：本地临时路径
function checkImage(path, image, canvas) {
  if (!path) return Promise.resolve({ status: 'error' })
  return compressForCheck(canvas, image, path)
    .then(upload)
    .then((fileID) => {
      if (!fileID) return { status: 'error' }
      // 云函数检测完毕后会立即删除该临时文件
      return callFunction({ type: 'checkImage', fileID }).then((result) => ({ status: normalize(result) }))
    })
    .catch(() => ({ status: 'error' }))
}

const MESSAGES = {
  risky: '内容含违规信息，请修改后再试',
  error: '安全检测暂不可用，请检查网络后重试',
}

module.exports = { checkText, checkTexts, isTextPassed, checkImage, MESSAGES }