import { NextRequest, NextResponse } from 'next/server'
import { prisma } from '@/lib/prisma'
import { calculateNextRun } from '@/lib/agents/schedule'

export const dynamic = 'force-dynamic'

/**
 * POST /api/cron/agents
 *
 * Finds all enabled, non-manual agents whose nextRun <= now,
 * executes them, and schedules the next run.
 *
 * Optional auth: set CRON_SECRET env var, callers must pass
 * Authorization: Bearer <CRON_SECRET>
 */
export async function POST(request: NextRequest) {
  const cronSecret = process.env.CRON_SECRET
  if (!cronSecret) {
    console.error('[CronAgents] CRON_SECRET env var is required but not set')
    return NextResponse.json({ error: 'Server misconfiguration' }, { status: 500 })
  }
  const authHeader = request.headers.get('authorization')
  if (authHeader !== `Bearer ${cronSecret}`) {
    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
  }

  try {
    const now = new Date()

    // Due = nextRun in the past; also backfill agents whose nextRun was never set
    // (legacy / toggle bug) — but only schedule them, don't stampede-execute all nulls
    const dueAgents = await prisma.agent.findMany({
      where: {
        isEnabled: true,
        frequency: { notIn: ['manual', 'one-shot'] },
        nextRun: { lte: now },
      },
      select: {
        id: true,
        userId: true,
        frequency: true,
        scheduledTime: true,
        scheduledDay: true,
        timezone: true,
        nextRun: true,
      },
      orderBy: { nextRun: 'asc' },
    })

    // Repair: set nextRun for enabled scheduled agents stuck with null
    const unscheduled = await prisma.agent.findMany({
      where: {
        isEnabled: true,
        frequency: { notIn: ['manual', 'one-shot'] },
        nextRun: null,
      },
      select: {
        id: true,
        userId: true,
        frequency: true,
        scheduledTime: true,
        scheduledDay: true,
        timezone: true,
      },
      take: 50,
    })
    const repairedDue: typeof dueAgents = []
    for (const a of unscheduled) {
      const nextRun = calculateNextRun({
        frequency: a.frequency,
        scheduledTime: a.scheduledTime,
        scheduledDay: a.scheduledDay,
        timezone: a.timezone,
      })
      // Si le créneau calculé est déjà passé / immédiat → exécuter ce cycle
      const effective = !nextRun || nextRun <= now ? now : nextRun
      await prisma.agent.update({ where: { id: a.id }, data: { nextRun: effective } })
      if (effective <= now) {
        repairedDue.push({
          id: a.id,
          userId: a.userId,
          frequency: a.frequency,
          scheduledTime: a.scheduledTime,
          scheduledDay: a.scheduledDay,
          timezone: a.timezone,
          nextRun: effective,
        })
      }
    }

    const queue = [...dueAgents]
    const seen = new Set(dueAgents.map((a) => a.id))
    for (const a of repairedDue) {
      if (!seen.has(a.id)) {
        queue.push(a)
        seen.add(a.id)
      }
    }

    if (queue.length === 0) {
      return NextResponse.json({
        success: true,
        executed: 0,
        repairedSchedules: unscheduled.length,
      })
    }

    const results: { id: string; success: boolean; error?: string }[] = []

    // Execute agents sequentially (max 5 per cycle — rattrapage + due)
    for (const agent of queue.slice(0, 5)) {
      try {
        const { executeAgent } = await import('@/lib/ai/services/agent-executor.service')
        const result = await executeAgent(agent.id, agent.userId)

        const nextRun = calculateNextRun({
          frequency: agent.frequency,
          scheduledTime: agent.scheduledTime,
          scheduledDay: agent.scheduledDay,
          timezone: agent.timezone,
        })

        await prisma.agent.update({
          where: { id: agent.id },
          data: { nextRun },
        })

        results.push({ id: agent.id, success: result.success, error: result.error })
      } catch (error) {
        const msg = error instanceof Error ? error.message : 'Unknown error'
        console.error(`[CronAgents] Agent ${agent.id} failed:`, msg)

        const nextRun = calculateNextRun({
          frequency: agent.frequency,
          scheduledTime: agent.scheduledTime,
          scheduledDay: agent.scheduledDay,
          timezone: agent.timezone,
        })
        await prisma.agent.update({
          where: { id: agent.id },
          data: { nextRun },
        })

        results.push({ id: agent.id, success: false, error: msg })
      }
    }

    return NextResponse.json({
      success: true,
      executed: results.length,
      results,
    })
  } catch (error) {
    console.error('[CronAgents] Error:', error)
    return NextResponse.json(
      { success: false, error: 'Internal Server Error' },
      { status: 500 }
    )
  }
}