import { NextRequest, NextResponse } from 'next/server'
import { prisma } from '@/lib/prisma'
import { verifyJWT } from '@/lib/auth'

export async function GET(req: NextRequest) {
  const auth = req.headers.get('authorization')
  if (!auth?.startsWith('Bearer ')) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
  const payload = await verifyJWT(auth.slice(7))
  if (!payload) return NextResponse.json({ error: 'Invalid token' }, { status: 401 })

  const today = new Date().toISOString().slice(0, 10)
  const [user, reading] = await Promise.all([
    prisma.user.findUnique({ where: { id: payload.id }, select: { quranStreak: true, quranStreakDate: true } }),
    prisma.quranReading.findUnique({ where: { userId_date: { userId: payload.id, date: today } } }),
  ])

  return NextResponse.json({
    streak: user?.quranStreak ?? 0,
    todayRead: reading?.pagesRead ?? 0,
    todayGoal: reading?.goalPages ?? 1,
    date: today,
  })
}

export async function POST(req: NextRequest) {
  const auth = req.headers.get('authorization')
  if (!auth?.startsWith('Bearer ')) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
  const payload = await verifyJWT(auth.slice(7))
  if (!payload) return NextResponse.json({ error: 'Invalid token' }, { status: 401 })

  const { pages = 1, goal = 1 } = await req.json()
  const today = new Date().toISOString().slice(0, 10)

  const reading = await prisma.quranReading.upsert({
    where: { userId_date: { userId: payload.id, date: today } },
    create: { userId: payload.id, date: today, pagesRead: pages, goalPages: goal },
    update: { pagesRead: pages, goalPages: goal },
  })

  const goalMet = reading.pagesRead >= reading.goalPages

  if (goalMet) {
    const user = await prisma.user.findUnique({
      where: { id: payload.id },
      select: { quranStreak: true, quranStreakDate: true },
    })
    const yesterday = new Date()
    yesterday.setDate(yesterday.getDate() - 1)
    const yesterdayStr = yesterday.toISOString().slice(0, 10)
    const lastDate = user?.quranStreakDate?.toISOString().slice(0, 10)

    let newStreak = 1
    if (lastDate === yesterdayStr) newStreak = (user?.quranStreak ?? 0) + 1
    else if (lastDate === today) newStreak = user?.quranStreak ?? 1

    await prisma.user.update({
      where: { id: payload.id },
      data: { quranStreak: newStreak, quranStreakDate: new Date() },
    })

    return NextResponse.json({ streak: newStreak, goalMet: true, pagesRead: reading.pagesRead })
  }

  return NextResponse.json({ streak: null, goalMet: false, pagesRead: reading.pagesRead })
}