import { defineConfig, loadEnv } from 'vite'
import react from '@vitejs/plugin-react'
import tailwindcss from '@tailwindcss/vite'
import path from 'path'
import fs from 'fs'

/** Same default as server when `server/.env` has no PORT (see repo root `mailflow.dev.port.json`). */
function readMailflowDevPort(): string {
  const f = path.resolve(__dirname, '../mailflow.dev.port.json')
  try {
    const j = JSON.parse(fs.readFileSync(f, 'utf8')) as { port?: number }
    if (j.port != null && Number.isFinite(Number(j.port))) return String(j.port)
  } catch {
    /* missing or invalid */
  }
  return '3030'
}

/** Align Vite proxy with server/.env PORT (client/.env does not load server PORT). */
function readBackendPortFromServerEnv(): string {
  const envFile = path.resolve(__dirname, '../server/.env')
  try {
    let text = fs.readFileSync(envFile, 'utf8')
    if (text.charCodeAt(0) === 0xfeff) text = text.slice(1)
    for (const line of text.split(/\r?\n/)) {
      if (/^\s*#/.test(line)) continue
      const noComment = line.split('#')[0]?.trim() || ''
      const m = /^\s*PORT\s*=\s*"?(\d+)"?/i.exec(noComment)
      if (m) return m[1]
    }
  } catch {
    /* no server/.env */
  }
  return readMailflowDevPort()
}

/** Origin only (no trailing /api) — matches client api.ts / VITE_DEV_BACKEND_ORIGIN contract. */
function stripTrailingApiFromOrigin(o: string): string {
  let s = o.replace(/\/$/, '')
  while (s.endsWith('/api')) {
    s = s.slice(0, -4).replace(/\/+$/, '')
  }
  return s
}

// https://vite.dev/config/
export default defineConfig(({ mode }) => {
  const env = loadEnv(mode, __dirname, '')
  const appwriteDevOrigin = (env.APPWRITE_DEV_ORIGIN || '').replace(/\/$/, '')
  const defaultApiOrigin = `http://127.0.0.1:${readBackendPortFromServerEnv()}`
  // 127.0.0.1 avoids Windows localhost → IPv6 (::1) vs backend listening on IPv4-only
  const apiDevTarget = stripTrailingApiFromOrigin(env.VITE_DEV_API_ORIGIN || defaultApiOrigin)

  const proxy: Record<
    string,
    { target: string; changeOrigin: boolean; secure?: boolean }
  > = {
    '/api': {
      target: apiDevTarget,
      changeOrigin: true,
    },
    '/stripe': {
      target: apiDevTarget,
      changeOrigin: true,
    },
  }

  // Dev: Browser → localhost:5173/v1/* → Appwrite (umgeht CORS, wenn die Console nur z. B. webklar.com erlaubt)
  if (mode === 'development' && appwriteDevOrigin) {
    proxy['/v1'] = {
      target: appwriteDevOrigin,
      changeOrigin: true,
      secure: true,
    }
  }

  return {
    // Browser ruft Express direkt an (CORS) — vermeidet 404, wenn der Vite-/api-Proxy nicht greift
    define:
      mode === 'development'
        ? {
            'import.meta.env.VITE_DEV_BACKEND_ORIGIN': JSON.stringify(apiDevTarget),
          }
        : {},
    plugins: [react(), tailwindcss()],
    resolve: {
      alias: {
        '@': path.resolve(__dirname, './src'),
      },
    },
    server: {
      host: true,
      port: 5173,
      // Wenn 5173 schon belegt ist, nicht still auf einen anderen Port wechseln — sonst öffnet man oft noch die alte URL und bekommt für /api 404.
      strictPort: true,
      proxy,
    },
    // `vite preview` hat standardmäßig keinen Dev-Proxy — sonst wäre /api ein 404.
    preview: { proxy },
  }
})