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()

    const dueAgents = await prisma.agent.findMany({
      where: {
        isEnabled: true,
        frequency: { not: 'manual' },
        nextRun: { lte: now },
      },
      select: {
        id: true,
        userId: true,
        frequency: true,
        scheduledTime: true,
        scheduledDay: true,
        timezone: true,
      },
    })

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

    console.log(`[CronAgents] Found ${dueAgents.length} due agent(s): ${dueAgents.map(a => a.id).join(', ')}`)

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

    // Execute agents sequentially (max 3 per cycle)
    for (const agent of dueAgents.slice(0, 3)) {
      try {
        console.log(`[CronAgents] Executing agent ${agent.id} (${agent.frequency})`)
        const { executeAgent } = await import('@/lib/ai/services/agent-executor.service')
        const result = await executeAgent(agent.id, agent.userId)

        // Calculate and set next run
        const nextRun = calculateNextRun({
          frequency: agent.frequency,
          scheduledTime: agent.scheduledTime,
          scheduledDay: agent.scheduledDay,
          timezone: agent.timezone,
        })

        console.log(`[CronAgents] Agent ${agent.id} done. success=${result.success}, nextRun=${nextRun?.toISOString() ?? 'null'}`)

        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)

        // Still schedule next run even on failure
        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 }
    )
  }
}