import { NextRequest, NextResponse } from 'next/server'
import prisma from '@/lib/prisma'
import { revalidatePath } from 'next/cache'

// GET /api/labels/[id] - Get a specific label
export async function GET(
  request: NextRequest,
  { params }: { params: Promise<{ id: string }> }
) {
  try {
    const { id } = await params
    const label = await prisma.label.findUnique({
      where: { id }
    })

    if (!label) {
      return NextResponse.json(
        { success: false, error: 'Label not found' },
        { status: 404 }
      )
    }

    return NextResponse.json({
      success: true,
      data: label
    })
  } catch (error) {
    console.error('GET /api/labels/[id] error:', error)
    return NextResponse.json(
      { success: false, error: 'Failed to fetch label' },
      { status: 500 }
    )
  }
}

// PUT /api/labels/[id] - Update a label
export async function PUT(
  request: NextRequest,
  { params }: { params: Promise<{ id: string }> }
) {
  try {
    const { id } = await params
    const body = await request.json()
    const { name, color } = body

    // Get the current label first
    const currentLabel = await prisma.label.findUnique({
      where: { id }
    })

    if (!currentLabel) {
      return NextResponse.json(
        { success: false, error: 'Label not found' },
        { status: 404 }
      )
    }

    const newName = name ? name.trim() : currentLabel.name

    // If renaming, update all notes that use this label
    if (name && name.trim() !== currentLabel.name) {
      // Get all notes that use this label
      const allNotes = await prisma.note.findMany({
        where: {
          userId: currentLabel.userId,
          labels: { not: null }
        },
        select: { id: true, labels: true }
      })

      // Update the label name in all notes that use it
      for (const note of allNotes) {
        if (note.labels) {
          try {
            const noteLabels: string[] = JSON.parse(note.labels)
            const updatedLabels = noteLabels.map(l =>
              l.toLowerCase() === currentLabel.name.toLowerCase() ? newName : l
            )

            // Update the note if labels changed
            if (JSON.stringify(updatedLabels) !== JSON.stringify(noteLabels)) {
              await prisma.note.update({
                where: { id: note.id },
                data: {
                  labels: JSON.stringify(updatedLabels)
                }
              })
            }
          } catch (e) {
            console.error(`Failed to parse labels for note ${note.id}:`, e)
          }
        }
      }
    }

    // Now update the label record
    const label = await prisma.label.update({
      where: { id },
      data: {
        ...(name && { name: newName }),
        ...(color && { color })
      }
    })

    // Revalidate to refresh UI
    revalidatePath('/')

    return NextResponse.json({
      success: true,
      data: label
    })
  } catch (error) {
    console.error('PUT /api/labels/[id] error:', error)
    return NextResponse.json(
      { success: false, error: 'Failed to update label' },
      { status: 500 }
    )
  }
}

// DELETE /api/labels/[id] - Delete a label
export async function DELETE(
  request: NextRequest,
  { params }: { params: Promise<{ id: string }> }
) {
  try {
    const { id } = await params

    // First, get the label to know its name and userId
    const label = await prisma.label.findUnique({
      where: { id }
    })

    if (!label) {
      return NextResponse.json(
        { success: false, error: 'Label not found' },
        { status: 404 }
      )
    }

    // Get all notes that use this label
    const allNotes = await prisma.note.findMany({
      where: {
        userId: label.userId,
        labels: { not: null }
      },
      select: { id: true, labels: true }
    })

    // Remove the label from all notes that use it
    for (const note of allNotes) {
      if (note.labels) {
        try {
          const noteLabels: string[] = JSON.parse(note.labels)
          const filteredLabels = noteLabels.filter(
            l => l.toLowerCase() !== label.name.toLowerCase()
          )

          // Update the note if labels changed
          if (filteredLabels.length !== noteLabels.length) {
            await prisma.note.update({
              where: { id: note.id },
              data: {
                labels: filteredLabels.length > 0 ? JSON.stringify(filteredLabels) : null
              }
            })
          }
        } catch (e) {
          console.error(`Failed to parse labels for note ${note.id}:`, e)
        }
      }
    }

    // Now delete the label record
    await prisma.label.delete({
      where: { id }
    })

    // Revalidate to refresh UI
    revalidatePath('/')

    return NextResponse.json({
      success: true,
      message: `Label "${label.name}" deleted and removed from ${allNotes.length} notes`
    })
  } catch (error) {
    console.error('DELETE /api/labels/[id] error:', error)
    return NextResponse.json(
      { success: false, error: 'Failed to delete label' },
      { status: 500 }
    )
  }
}