import { defineConfig, loadEnv } from 'vite'
import uni from '@dcloudio/vite-plugin-uni'
import path from 'path'
import fs from 'node:fs'
import type { Plugin } from 'vite'
import {
  STATIC_ASSETS_BASE_URL_PRODUCTION,
  STATIC_ASSETS_BASE_URL_TEST
} from './src/config/static-assets-defaults'

function normalizeStaticBase(url: string): string {
  const u = url.trim()
  if (!u) return STATIC_ASSETS_BASE_URL_TEST
  return u.endsWith('/') ? u : `${u}/`
}

function resolveStaticBaseFromViteEnv(mode: string, env: Record<string, string>): string {
  const explicit = env.VITE_STATIC_ASSETS_BASE_URL?.trim()
  if (explicit) return normalizeStaticBase(explicit)
  return normalizeStaticBase(mode === 'production' ? STATIC_ASSETS_BASE_URL_PRODUCTION : STATIC_ASSETS_BASE_URL_TEST)
}

const TABBAR_PLACEHOLDER = '__STATIC_ASSETS_BASE_URL__'

/** pages.json 中 tabBar 图标占位符：开发 / H5 构建时替换为真实根地址，与 scripts/pages-tabbar-migrate.mjs 行为一致 */
function pagesJsonTabbarPlugin(staticAssetsBase: string, root: string): Plugin {
  const pagesPath = path.join(root, 'src/pages.json')
  const bakPath = path.join(root, 'src/.pages-json.tabbar-placeholder.bak')
  let isServe = false
  /** 避免 dev 关闭时 close / 信号 重复还原 */
  let devShutdownDone = false

  function materialize() {
    const raw = fs.readFileSync(pagesPath, 'utf8')
    if (!raw.includes(TABBAR_PLACEHOLDER)) return
    fs.writeFileSync(bakPath, raw, 'utf8')
    const base = normalizeStaticBase(staticAssetsBase)
    fs.writeFileSync(pagesPath, raw.replace(new RegExp(TABBAR_PLACEHOLDER, 'g'), base), 'utf8')
  }

  /** 从备份还原占位符版本；无备份则跳过（幂等，可多次调用） */
  function restore() {
    if (!fs.existsSync(bakPath)) return
    fs.copyFileSync(bakPath, pagesPath)
    fs.unlinkSync(bakPath)
  }

  return {
    name: 'pages-json-tabbar-static-base',
    configResolved(config) {
      isServe = config.command === 'serve'
    },
    buildStart() {
      if (!isServe) materialize()
    },
    buildEnd() {
      if (!isServe) restore()
    },
    configureServer(server) {
      materialize()
      const onShutdown = () => {
        if (devShutdownDone) return
        devShutdownDone = true
        restore()
      }
      server.httpServer?.once('close', onShutdown)
      process.once('SIGINT', onShutdown)
      process.once('SIGTERM', onShutdown)
    }
  }
}

export default defineConfig(({ mode }) => {
  const env = loadEnv(mode, process.cwd(), '')
  const staticAssetsBase = resolveStaticBaseFromViteEnv(mode, env)

  return {
    plugins: [
      uni(),
      pagesJsonTabbarPlugin(staticAssetsBase, __dirname),
      {
        name: 'replace-static-assets-base-in-html',
        transformIndexHtml(html) {
          return html.replace(/__STATIC_ASSETS_BASE_URL__/g, staticAssetsBase)
        }
      }
    ],
    resolve: {
      alias: {
        '@': path.resolve(__dirname, 'src')
      }
    },
    css: {
      preprocessorOptions: {
        scss: {
          additionalData: '@import "@/styles/variables.scss";'
        }
      }
    }
  }
})