export const dynamic = 'force-dynamic'
import { NextResponse } from 'next/server'
import { google } from 'googleapis'
import * as fs from 'fs'
import * as path from 'path'

function getAuth() {
  // Service account JSON (inline or from file)
  const saJson = process.env.GOOGLE_SA_JSON
  if (saJson) {
    const sa = JSON.parse(saJson)
    return new google.auth.GoogleAuth({
      credentials: sa,
      scopes: ['https://www.googleapis.com/auth/calendar.readonly'],
    })
  }
  // Fallback: file
  const saPath = path.join(process.cwd(), 'google-sa.json')
  if (fs.existsSync(saPath)) {
    return new google.auth.GoogleAuth({
      keyFile: saPath,
      scopes: ['https://www.googleapis.com/auth/calendar.readonly'],
    })
  }
  return null
}

export async function GET(req: Request) {
  const { searchParams } = new URL(req.url)
  const range = searchParams.get('range') || 'today'

  const auth = getAuth()
  if (!auth) {
    return NextResponse.json({ events: [], error: 'not_configured' })
  }

  const daniilCalendarId = process.env.DANIIL_CALENDAR_ID || 'daniilklimov25@gmail.com'
  const svetaCalendarId = process.env.SVETA_CALENDAR_ID || ''

  const now = new Date()
  let timeMin: string
  let timeMax: string

  if (range === 'today') {
    timeMin = new Date(now.getFullYear(), now.getMonth(), now.getDate()).toISOString()
    timeMax = new Date(now.getFullYear(), now.getMonth(), now.getDate() + 1).toISOString()
  } else if (range === 'week') {
    timeMin = new Date(now.getFullYear(), now.getMonth(), now.getDate()).toISOString()
    timeMax = new Date(now.getFullYear(), now.getMonth(), now.getDate() + 7).toISOString()
  } else {
    timeMin = new Date(now.getFullYear(), now.getMonth(), 1).toISOString()
    timeMax = new Date(now.getFullYear(), now.getMonth() + 1, 0, 23, 59).toISOString()
  }

  const calendarClient = google.calendar({ version: 'v3', auth: auth as any })

  const calendars = [
    { id: daniilCalendarId, owner: 'daniil', color: '#6366f1', name: 'Даниил' },
    ...(svetaCalendarId ? [{ id: svetaCalendarId, owner: 'sveta', color: '#ec4899', name: 'Света' }] : [])
  ]

  const results = await Promise.allSettled(
    calendars.map(cal =>
      calendarClient.events.list({
        calendarId: cal.id,
        timeMin,
        timeMax,
        singleEvents: true,
        orderBy: 'startTime',
        maxResults: 100,
      }).then(r => ({ ...cal, events: r.data.items || [] }))
    )
  )

  const allEvents = results
    .filter(r => r.status === 'fulfilled')
    .flatMap(r => {
      const val = (r as PromiseFulfilledResult<any>).value
      return val.events.map((e: any) => ({
        id: e.id,
        title: e.summary || '(без названия)',
        start: e.start?.dateTime || e.start?.date,
        end: e.end?.dateTime || e.end?.date,
        allDay: !e.start?.dateTime,
        description: e.description || null,
        location: e.location || null,
        owner: val.owner,
        ownerName: val.name,
        color: val.color,
      }))
    })
    .sort((a, b) => new Date(a.start).getTime() - new Date(b.start).getTime())

  const errors = results
    .filter(r => r.status === 'rejected')
    .map(r => (r as PromiseRejectedResult).reason?.message || 'unknown')

  return NextResponse.json({ events: allEvents, errors: errors.length ? errors : undefined, fetchedAt: new Date().toISOString() })
}