var db = require('../../common/db')
var auth = require('../../common/auth')
var RESPONSE = require('../../common/response').RESPONSE
var ERROR_CODES = require('../../common/response').ERROR_CODES

exports.main_handler = async function (event) {
  try {
    var method = event.httpMethod || 'GET'
    var path = event.path || ''
    var body = parseBody(event)

    if (method === 'POST' && path === '/api/v1/treatment/sync') {
      return await syncRecord(event, body)
    }
    if (method === 'GET' && path === '/api/v1/treatment/history') {
      return await getHistory(event, body)
    }

    return RESPONSE.error(ERROR_CODES.PARAM_ERROR.code, 'unknown route')
  } catch (err) {
    console.error('treatment error:', err)
    return RESPONSE.error(ERROR_CODES.SERVER_ERROR.code, err.message)
  }
}

async function syncRecord(event, body) {
  var user = auth.extractUser(event)
  if (!user) return RESPONSE.error(ERROR_CODES.INVALID_TOKEN.code, ERROR_CODES.INVALID_TOKEN.message)

  if (!body.session_id || !body.device_id) {
    return RESPONSE.error(ERROR_CODES.PARAM_ERROR.code, 'missing session_id or device_id')
  }

  var devices = await db.query(
    'SELECT id FROM devices WHERE device_id = ? AND deleted_at IS NULL LIMIT 1',
    [body.device_id]
  )
  if (devices.length === 0) {
    return RESPONSE.error(ERROR_CODES.DEVICE_NOT_FOUND.code, ERROR_CODES.DEVICE_NOT_FOUND.message)
  }
  var devicePkId = devices[0].id

  var existingSession = await db.query(
    'SELECT id FROM sessions WHERE session_id = ? LIMIT 1',
    [body.session_id]
  )

  if (existingSession.length === 0) {
    await db.insert(
      'INSERT INTO sessions (session_id, user_id, device_id, status, started_at, ended_at) VALUES (?, ?, ?, 2, ?, ?)',
      [
        body.session_id,
        user.user_id,
        devicePkId,
        body.start_time ? new Date(body.start_time).toISOString().slice(0, 19).replace('T', ' ') : null,
        body.end_time ? new Date(body.end_time).toISOString().slice(0, 19).replace('T', ' ') : null
      ]
    )
  }

  var existingRecord = await db.query(
    'SELECT id FROM treatment_records WHERE session_id = ? LIMIT 1',
    [body.session_id]
  )

  if (existingRecord.length > 0) {
    return RESPONSE.success({ record_id: existingRecord[0].id })
  }

  var result = await db.insert(
    'INSERT INTO treatment_records (session_id, user_id, device_id, regions, total_duration_ms, mode, avg_pd, sync_status, synced_at, started_at, ended_at) ' +
    'VALUES (?, ?, ?, ?, ?, ?, ?, 2, NOW(), ?, ?)',
    [
      body.session_id,
      user.user_id,
      devicePkId,
      body.regions || null,
      body.total_duration_ms || null,
      body.mode !== undefined ? body.mode : null,
      body.avg_pd || null,
      body.start_time ? new Date(body.start_time).toISOString().slice(0, 19).replace('T', ' ') : null,
      body.end_time ? new Date(body.end_time).toISOString().slice(0, 19).replace('T', ' ') : null
    ]
  )

  if (body.pd_data && Array.isArray(body.pd_data)) {
    for (var i = 0; i < body.pd_data.length; i++) {
      var pd = body.pd_data[i]
      await db.insert(
        'INSERT INTO pd_data (session_id, device_id, region_name, pd_value, recorded_at) VALUES (?, ?, ?, ?, ?)',
        [body.session_id, devicePkId, pd.name, pd.pd || null, new Date().toISOString().slice(0, 19).replace('T', ' ')]
      )
    }
  }

  return RESPONSE.success({ record_id: result.insertId })
}

async function getHistory(event, body) {
  var user = auth.extractUser(event)
  if (!user) return RESPONSE.error(ERROR_CODES.INVALID_TOKEN.code, ERROR_CODES.INVALID_TOKEN.message)

  var page = parseInt(body.page) || 1
  var pageSize = parseInt(body.page_size) || 20
  var offset = (page - 1) * pageSize

  var totalResult = await db.query(
    'SELECT COUNT(*) AS cnt FROM treatment_records WHERE user_id = ?',
    [user.user_id]
  )
  var total = totalResult[0].cnt

  var records = await db.query(
    'SELECT tr.id AS record_id, tr.session_id, tr.regions, tr.total_duration_ms, tr.mode, tr.avg_pd, tr.started_at AS start_time, tr.ended_at AS end_time, d.device_id, d.device_name ' +
    'FROM treatment_records tr ' +
    'JOIN devices d ON tr.device_id = d.id ' +
    'WHERE tr.user_id = ? ' +
    'ORDER BY tr.started_at DESC LIMIT ? OFFSET ?',
    [user.user_id, pageSize, offset]
  )

  return RESPONSE.paginate(records, total, page, pageSize)
}

function parseBody(event) {
  if (event.body) {
    try { return JSON.parse(event.body) } catch (e) { return {} }
  }
  return event.queryStringParameters || {}
}