import 'dotenv/config'
import express from 'express'
import mysql from 'mysql2/promise'
import path from 'node:path'
import { existsSync } from 'node:fs'
import { fileURLToPath } from 'node:url'

const app = express()
const port = Number(process.env.PORT ?? process.env.SERVER_PORT ?? 8787)
const tableName = process.env.DB_TABLE ?? 'badminton'

const currentFilePath = fileURLToPath(import.meta.url)
const currentDir = path.dirname(currentFilePath)
const projectRoot = path.resolve(currentDir, '..')
const distDir = path.join(projectRoot, 'dist')
const distReady = existsSync(path.join(distDir, 'index.html'))

const requiredEnv = ['DB_HOST', 'DB_PORT', 'DB_USER', 'DB_PASSWORD', 'DB_DATABASE']
const missingEnv = requiredEnv.filter((key) => !process.env[key])
const lineAccessToken =
  process.env.LINE_CHANNEL_ACCESS_TOKEN ?? process.env.channelAccessToken ?? ''
const lineTargetMode = (process.env.LINE_TARGET_MODE ?? 'local').toLowerCase()
const lineTargetId =
  process.env.LINE_TARGET_ID ??
  (lineTargetMode === 'prod'
    ? process.env.LINE_TARGET_ID_PROD ?? ''
    : process.env.LINE_TARGET_ID_LOCAL ?? '')

const pool =
  missingEnv.length === 0
    ? mysql.createPool({
        host: process.env.DB_HOST,
        port: Number(process.env.DB_PORT),
        user: process.env.DB_USER,
        password: process.env.DB_PASSWORD,
        database: process.env.DB_DATABASE,
        charset: 'utf8mb4',
        waitForConnections: true,
        connectionLimit: 10,
      })
    : null

app.use(express.json())

app.get('/api/health', (_request, response) => {
  response.json({
    ok: true,
    dbReady: Boolean(pool),
    distReady,
    lineReady: Boolean(lineAccessToken && lineTargetId),
    lineTargetMode,
    missingEnv,
  })
})

app.post('/api/line/push-match-results', async (request, response) => {
  const { time, teams } = request.body ?? {}

  if (typeof time !== 'string' || !Array.isArray(teams)) {
    response.status(400).json({
      ok: false,
      message: '送出的 LINE 訊息資料格式不正確。',
    })
    return
  }

  if (!lineAccessToken || !lineTargetId) {
    response.status(500).json({
      ok: false,
      message:
        'LINE 推播環境變數缺少，請檢查 LINE_CHANNEL_ACCESS_TOKEN 與 LINE_TARGET_ID_LOCAL / LINE_TARGET_ID_PROD。',
    })
    return
  }

  try {
    const message = buildLineFlexMessage(time, teams)
    const lineResponse = await fetch('https://api.line.me/v2/bot/message/push', {
      method: 'POST',
      headers: {
        Authorization: `Bearer ${lineAccessToken}`,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({
        to: lineTargetId,
        messages: [message],
      }),
    })

    if (!lineResponse.ok) {
      const errorText = await lineResponse.text()
      throw new Error(`LINE 推播失敗：${errorText}`)
    }

    response.json({
      ok: true,
      message: '已推送到 LINE。',
    })
  } catch (error) {
    console.error('line push error:', error)
    response.status(500).json({
      ok: false,
      message: error instanceof Error ? error.message : 'LINE 推播失敗。',
    })
  }
})

app.get('/api/match-results/:time', async (request, response) => {
  if (!pool) {
    response.status(500).json({
      ok: false,
      message: `資料庫環境變數缺少：${missingEnv.join(', ')}`,
    })
    return
  }

  const time = String(request.params.time ?? '')

  if (!/^\d{8}$/.test(time)) {
    response.status(400).json({
      ok: false,
      message: '日期格式不正確，請使用 YYYYMMDD。',
    })
    return
  }

  try {
    await ensureTable(pool, tableName)
    const [rows] = await pool.execute(
      `SELECT time, personnel, battlecombination FROM \`${tableName}\` WHERE time = ? LIMIT 1`,
      [Number(time)],
    )

    const record = rows[0]

    if (!record) {
      response.status(404).json({
        ok: false,
        message: '指定日期沒有資料。',
      })
      return
    }

    response.json({
      ok: true,
      data: record,
    })
  } catch (error) {
    console.error('match-results load error:', error)
    response.status(500).json({
      ok: false,
      message: error instanceof Error ? error.message : '資料庫讀取失敗。',
    })
  }
})

app.post('/api/match-results', async (request, response) => {
  if (!pool) {
    response.status(500).json({
      ok: false,
      message: `資料庫環境變數缺少：${missingEnv.join(', ')}`,
    })
    return
  }

  const { time, areaA, areaB, teams } = request.body ?? {}

  if (
    typeof time !== 'string' ||
    !Array.isArray(areaA) ||
    !Array.isArray(areaB) ||
    !Array.isArray(teams)
  ) {
    response.status(400).json({
      ok: false,
      message: '送出的資料格式不正確。',
    })
    return
  }

  try {
    await ensureTable(pool, tableName)
    const personnel = JSON.stringify([
      ...areaA.map((name) => [1, name]),
      ...areaB.map((name) => [0, name]),
    ])
    const battlecombination = JSON.stringify(
      Object.fromEntries(
        teams.map((round, index) => [
          String(index),
          round.teams.map((team) => [team.a, team.b]),
        ]),
      ),
    )

    await pool.execute(
      `
        INSERT INTO \`${tableName}\` (time, personnel, battlecombination)
        VALUES (?, ?, ?)
        ON DUPLICATE KEY UPDATE
          personnel = VALUES(personnel),
          battlecombination = VALUES(battlecombination)
      `,
      [Number(time), personnel, battlecombination],
    )

    response.json({
      ok: true,
      message: '已寫入資料庫。',
    })
  } catch (error) {
    console.error('match-results save error:', error)
    response.status(500).json({
      ok: false,
      message: error instanceof Error ? error.message : '資料庫寫入失敗。',
    })
  }
})

if (distReady) {
  app.use(express.static(distDir))

  app.get(/^(?!\/api).*/, (_request, response) => {
    response.sendFile(path.join(distDir, 'index.html'))
  })
} else {
  app.get('/', (_request, response) => {
    response
      .status(503)
      .send('前端尚未建置，請先執行 npm run build 或使用 Docker 映像部署。')
  })
}

app.listen(port, () => {
  console.log(`Server ready on http://localhost:${port}`)
  console.log(`Static files: ${distReady ? 'loaded' : 'missing'}`)
  console.log(`LINE target mode: ${lineTargetMode}`)
  if (missingEnv.length > 0) {
    console.log(`Missing env: ${missingEnv.join(', ')}`)
  }
})

async function ensureTable(poolInstance, currentTableName) {
  await poolInstance.execute(`
    CREATE TABLE IF NOT EXISTS \`${currentTableName}\` (
      time INT(11) NOT NULL,
      personnel TEXT NOT NULL,
      battlecombination TEXT DEFAULT NULL,
      PRIMARY KEY (time)
    ) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci
  `)
}

function buildLineFlexMessage(time, rounds) {
  const dateText = `${time.slice(0, 4)}-${time.slice(4, 6)}-${time.slice(6, 8)}`

  return {
    type: 'flex',
    altText: `${dateText} 羽球隊伍配對`,
    contents: {
      type: 'carousel',
      contents: rounds.map((round, roundIndex) => ({
        type: 'bubble',
        size: 'micro',
        body: {
          type: 'box',
          layout: 'vertical',
          contents: [
            {
              type: 'text',
              text: '勝皇羽球團',
              weight: 'bold',
              color: '#1DB446',
              size: 'sm',
            },
            {
              type: 'text',
              text: dateText,
              weight: 'bold',
              size: 'xl',
              margin: 'sm',
            },
            {
              type: 'text',
              text: `第${roundIndex + 1}輪`,
              weight: 'bold',
              size: 'xxl',
              margin: 'sm',
            },
            {
              type: 'separator',
              margin: 'md',
            },
            {
              type: 'box',
              layout: 'horizontal',
              contents: [
                {
                  type: 'text',
                  text: '一號隊友',
                  size: 'sm',
                  flex: 0,
                },
                {
                  type: 'text',
                  text: '二號隊友',
                  size: 'sm',
                  align: 'center',
                },
              ],
              margin: 'md',
            },
            {
              type: 'separator',
              margin: 'sm',
            },
            {
              type: 'box',
              layout: 'vertical',
              spacing: 'sm',
              margin: 'md',
              contents: round.teams.map((team) => ({
                type: 'box',
                layout: 'horizontal',
                contents: [
                  {
                    type: 'text',
                    text: team.a,
                    size: 'sm',
                    flex: 0,
                  },
                  {
                    type: 'text',
                    text: team.b,
                    size: 'sm',
                    align: 'center',
                  },
                ],
              })),
            },
          ],
        },
        styles: {
          footer: {
            separator: true,
          },
        },
      })),
    },
  }
}