const fs = require('fs')
const path = require('path')

const {
  removeExt,
  normalizePath
} = require('./util')

const {
  getJson,
  parseJson
} = require('./json')

let mainEntry = ''
let nvueMainEntry = ''

function getMainEntry () {
  if (!mainEntry) {
    mainEntry = fs.existsSync(path.resolve(process.env.UNI_INPUT_DIR, 'main.ts')) ? 'main.ts' : 'main.js'
  }
  return mainEntry
}

function getNVueMainEntry () {
  if (!nvueMainEntry) {
    nvueMainEntry = fs.existsSync(path.resolve(process.env.UNI_INPUT_DIR, 'main.js')) ? 'main.js' : '.main.js'
    if (nvueMainEntry === '.main.js') {
      fs.writeFileSync(path.resolve(process.env.UNI_INPUT_DIR, '.main.js'), '')
    }
  }
  return nvueMainEntry
}

function getPagesJson () {
  return processPagesJson(getJson('pages.json', true))
}

function parsePagesJson (content, loader) {
  return processPagesJson(parseJson(content, true), loader)
}

function filterPages (pages = [], root) {
  for (let i = pages.length - 1; i >= 0; i--) {
    const page = pages[i]
    if (!isValidPage(page, root)) {
      pages.splice(i, 1)
    }
  }
}

const pagesJsonJsFileName = 'pages.js'

function processPagesJson (pagesJson, loader = {
  addDependency: function () {}
}) {
  const pagesJsonJsPath = path.resolve(process.env.UNI_INPUT_DIR, pagesJsonJsFileName)
  if (fs.existsSync(pagesJsonJsPath)) {
    delete require.cache[pagesJsonJsPath]
    const pagesJsonJsFn = require(pagesJsonJsPath)
    if (typeof pagesJsonJsFn === 'function') {
      pagesJson = pagesJsonJsFn(pagesJson, loader)
      if (!pagesJson) {
        console.error(`${pagesJsonJsFileName}  必须返回一个 json 对象`)
      }
    } else {
      console.error(`${pagesJsonJsFileName} 必须导出 function`)
    }
  }

  let uniNVueEntryPagePath
  if (pagesJson.pages && pagesJson.pages.length) { // 如果首页是 nvue
    if (isNVuePage(pagesJson.pages[0])) {
      uniNVueEntryPagePath = pagesJson.pages[0].path
    }
  }
  // pages
  filterPages(pagesJson.pages)
  // subPackages
  if (Array.isArray(pagesJson.subPackages) && pagesJson.subPackages.length) {
    pagesJson.subPackages.forEach(subPackage => {
      filterPages(subPackage.pages, subPackage.root)
    })
  }

  if (uniNVuePages.length) { // 直接挂在 pagesJson 上
    pagesJson.nvue = {
      pages: uniNVuePages.reverse()
    }
    if (uniNVueEntryPagePath) {
      pagesJson.nvue.entryPagePath = uniNVueEntryPagePath
    }
  }
  return pagesJson
}

function isNVuePage (page, root = '') {
  if (process.env.UNI_PLATFORM === 'app-plus') {
    const pagePath = path.join(root, page.path)
    if (fs.existsSync(path.resolve(process.env.UNI_INPUT_DIR, pagePath + '.nvue'))) { // cache一下结果？如果文件被删除，cache 就会出现错误
      return true
    }
  }
  return false
}

function isValidPage (page, root = '') {
  if (typeof page === 'string') { // 不合法的配置
    console.warn(`${page} 配置错误, 已被忽略, 查看文档: https://uniapp.dcloud.io/collocation/pages?id=pages`)
    return false
  }
  let pagePath = page.path

  if (pagePath.indexOf('platforms') === 0) { // 平台相关
    if (pagePath.indexOf('platforms/' + process.env.UNI_PLATFORM) === -1) { // 非本平台
      return false
    }
  }

  if (
    process.env.UNI_PLATFORM === 'app-plus' &&
    page.style
  ) {
    const subNVues = page.style.subNVues || (page.style['app-plus'] && page.style['app-plus']['subNVues'])
    if (Array.isArray(subNVues)) {
      subNVues.forEach(subNVue => {
        let subNVuePath = subNVue.path
        if (subNVuePath) {
          subNVuePath = subNVue.path.split('?')[0]
          const subNVuePagePath = removeExt(path.join(root, subNVuePath))

          // if (process.env.UNI_USING_NVUE_COMPILER) {
          process.UNI_NVUE_ENTRY[subNVuePagePath] = getNVueMainJsPath(subNVuePagePath)
          // } else {
          //   process.UNI_NVUE_ENTRY[subNVuePagePath] = path.resolve(process.env.UNI_INPUT_DIR,
          //     subNVuePagePath +
          //                   '.nvue') + '?entry'
          // }
        }
      })
    }
  } else {
    page.style && (delete page.style.subNVues)
  }

  if (isNVuePage(page, root)) {
    // 存储 nvue 相关信息
    pagePath = normalizePath(path.join(root, pagePath))

    process.UNI_NVUE_ENTRY[pagePath] = getNVueMainJsPath(pagePath)

    if (process.env.UNI_USING_V3) { // 不移除
      page.nvue = true
      return true
    } else {
      uniNVuePages.push({
        'path': pagePath + '.html',
        'style': page.style || {}
      })
      return false
    }
  }

  return true
}

function getMainJsPath (page) {
  return path.resolve(process.env.UNI_INPUT_DIR, getMainEntry() + '?' + JSON.stringify({
    page: encodeURIComponent(page)
  }))
}

function getNVueMainJsPath (page) {
  return path.resolve(process.env.UNI_INPUT_DIR, getNVueMainEntry() + '?' + JSON.stringify({
    page: encodeURIComponent(page)
  }))
}

process.UNI_ENTRY = {}
process.UNI_NVUE_ENTRY = {}

const uniNVuePages = []

function parsePages (pagesJson, pageCallback, subPageCallback) {
  if (!pagesJson) {
    pagesJson = getPagesJson()
  }

  // pages
  pagesJson.pages.forEach(page => {
    pageCallback && pageCallback(page)
  })
  // subPackages
  if (Array.isArray(pagesJson.subPackages) && pagesJson.subPackages.length) {
    pagesJson.subPackages.forEach((subPackage) => {
      const {
        root,
        pages
      } = subPackage
      pages.forEach(page => {
        root && subPageCallback && subPageCallback(root, page, subPackage)
      })
    })
  }
}

function parseEntry (pagesJson) {
  process.UNI_ENTRY = {
    'common/main': path.resolve(process.env.UNI_INPUT_DIR, getMainEntry())
  }

  process.UNI_SUB_PACKAGES_ROOT = {}

  process.UNI_NVUE_ENTRY = {}

  if (process.env.UNI_USING_NATIVE) {
    process.UNI_NVUE_ENTRY['app-config'] = path.resolve(process.env.UNI_INPUT_DIR, 'pages.json')
    process.UNI_NVUE_ENTRY['app-service'] = path.resolve(process.env.UNI_INPUT_DIR, getMainEntry())
  }

  uniNVuePages.length = 0

  if (!pagesJson) {
    pagesJson = getPagesJson() // 会检测修改 nvue entry
  }

  // pages
  pagesJson.pages.forEach(page => {
    process.UNI_ENTRY[page.path] = getMainJsPath(page.path)
  })
  // subPackages
  if (Array.isArray(pagesJson.subPackages) && pagesJson.subPackages.length) {
    pagesJson.subPackages.forEach(({
      root,
      pages
    }) => {
      Array.isArray(pages) && pages.forEach(page => {
        if (root) {
          const pagePath = normalizePath(path.join(root, page.path))
          process.UNI_ENTRY[pagePath] = getMainJsPath(pagePath)
          process.UNI_SUB_PACKAGES_ROOT[pagePath] = root
        }
      })
    })
  }
}

module.exports = {
  getMainEntry,
  getNVueMainEntry,
  parsePages,
  parseEntry,
  getPagesJson,
  parsePagesJson,
  pagesJsonJsFileName
}