import { NextRequest, NextResponse } from 'next/server'
import { z } from 'zod'
import { authMiddleware } from '@/lib/auth-middleware'
import connectDB from '@/lib/mongodb'
import { Transaction } from '@/models/transaction'
import { Billing } from '@/models/billing'

// Query parameters schema
const TransactionQuerySchema = z.object({
  page: z.string().optional().default('1'),
  limit: z.string().optional().default('10'),
  type: z.enum(['debit', 'credit', 'all']).optional().default('all'),
  service: z.string().optional(),
})

export async function GET(request: NextRequest) {
  try {
    // Authenticate user
    const user = await authMiddleware(request)
    if (!user) {
      return NextResponse.json(
        {
          success: false,
          error: { message: 'Authentication required', code: 'UNAUTHORIZED' },
        },
        { status: 401 }
      )
    }

    await connectDB()

    // Parse query parameters
    const { searchParams } = new URL(request.url)
    const queryParams = TransactionQuerySchema.parse({
      page: searchParams.get('page') || undefined,
      limit: searchParams.get('limit') || undefined,
      type: searchParams.get('type') || undefined,
      service: searchParams.get('service') || undefined,
    })

    const page = parseInt(queryParams.page)
    const limit = Math.min(parseInt(queryParams.limit), 100) // Max 100 per page
    const skip = (page - 1) * limit

    // Build query filter
    const filter: any = { email: user.email }

    if (queryParams.type !== 'all') {
      filter.type = queryParams.type
    }

    if (queryParams.service) {
      filter.service = { $regex: queryParams.service, $options: 'i' }
    }

    // Build billing filter
    const billingFilter: any = {
      $or: [{ user: user.email }, { siliconId: user.id }],
    }
    // console.log('billingFilter', user.email)
    if (queryParams.service) {
      billingFilter.service = { $regex: queryParams.service, $options: 'i' }
    }

    // Get both transactions and billing records
    const [transactions, billingRecords, transactionCount, billingCount] = await Promise.all([
      Transaction.find(filter).sort({ createdAt: -1 }).lean().exec(),
      Billing.find(billingFilter).sort({ createdAt: -1 }).lean().exec(),
      Transaction.countDocuments(filter).exec(),
      Billing.countDocuments(billingFilter).exec(),
    ])

    // Transform billing records to transaction format
    const transformedBillings = billingRecords.map((billing: any) => ({
      _id: billing._id,
      transactionId: billing.billing_id,
      type: 'debit' as const,
      amount: billing.amount,
      service: billing.service,
      serviceId: billing.serviceId,
      description: billing.remarks || `${billing.service} - ${billing.cycle} billing`,
      status: billing.status === 'pending' ? 'pending' : 'completed',
      previousBalance: 0, // We don't have this data in billing
      newBalance: 0, // We don't have this data in billing
      createdAt: billing.createdAt,
      updatedAt: billing.updatedAt,
      email: billing.user,
      userId: billing.siliconId,
    }))

    // Combine and sort all records
    const allRecords = [...transactions, ...transformedBillings].sort(
      (a, b) => new Date(b.createdAt).getTime() - new Date(a.createdAt).getTime()
    )

    // Apply type filter to combined records
    const filteredRecords =
      queryParams.type === 'all'
        ? allRecords
        : allRecords.filter((record) => record.type === queryParams.type)

    // Apply pagination to filtered records
    const totalCount = filteredRecords.length
    const paginatedRecords = filteredRecords.slice(skip, skip + limit)

    const totalPages = Math.ceil(totalCount / limit)

    return NextResponse.json({
      success: true,
      data: {
        transactions: paginatedRecords,
        pagination: {
          page,
          limit,
          totalCount,
          totalPages,
          hasNext: page < totalPages,
          hasPrev: page > 1,
        },
      },
    })
  } catch (error) {
    console.error('Get transactions error:', error)

    if (error instanceof z.ZodError) {
      return NextResponse.json(
        {
          success: false,
          error: {
            message: 'Invalid query parameters',
            code: 'VALIDATION_ERROR',
            details: error.format(),
          },
        },
        { status: 400 }
      )
    }

    return NextResponse.json(
      {
        success: false,
        error: { message: 'Failed to fetch transactions', code: 'INTERNAL_ERROR' },
      },
      { status: 500 }
    )
  }
}