import { NextRequest, NextResponse } from "next/server"
import { getSessionUser } from "@/lib/auth"
import { query } from "@/lib/db"

export async function GET(request: NextRequest) {
  try {
    const user = await getSessionUser()
    if (!user) return NextResponse.json({ error: "Unauthorized" }, { status: 401 })

    const { searchParams } = new URL(request.url)
    const entityType = searchParams.get("entityType")

    let sql = `SELECT id, entity_type, field_key, field_label, field_type, options, placeholder, default_value, section, is_required, sort_order, is_active, created_at
               FROM custom_field_definitions WHERE is_active = true`
    const params: any[] = []

    if (entityType) {
      sql += ` AND entity_type = $1`
      params.push(entityType)
    }

    sql += ` ORDER BY entity_type, sort_order`

    const result = await query(sql, params)
    return NextResponse.json(result.rows)
  } catch (error) {
    console.error("Custom fields API error:", error)
    const message = error instanceof Error ? error.message : "Failed to load custom fields"
    return NextResponse.json({ error: message }, { status: 500 })
  }
}

export async function POST(request: NextRequest) {
  try {
    const user = await getSessionUser()
    if (!user) return NextResponse.json({ error: "Unauthorized" }, { status: 401 })

    const body = await request.json()
    if (!body.entityType || !body.fieldKey || !body.fieldLabel) {
      return NextResponse.json({ error: "entityType, fieldKey, fieldLabel are required" }, { status: 400 })
    }

    const result = await query(
      `INSERT INTO custom_field_definitions (entity_type, field_key, field_label, field_type, options, placeholder, default_value, section, is_required, sort_order)
       VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10) RETURNING id`,
      [
        body.entityType,
        body.fieldKey,
        body.fieldLabel,
        body.fieldType || "text",
        body.options ? JSON.stringify(body.options) : null,
        body.placeholder || null,
        body.defaultValue || null,
        body.section || null,
        body.isRequired || false,
        body.sortOrder || 0,
      ]
    )

    return NextResponse.json({ success: true, id: result.rows[0].id }, { status: 201 })
  } catch (error: any) {
    if (error?.constraint === "uq_custom_field_entity_key") {
      return NextResponse.json({ error: "A field with this key already exists for this entity" }, { status: 409 })
    }
    console.error("Custom fields POST error:", error)
    const message = error instanceof Error ? error.message : "Failed to create custom field"
    return NextResponse.json({ error: message }, { status: 500 })
  }
}

export async function PATCH(request: NextRequest) {
  try {
    const user = await getSessionUser()
    if (!user) return NextResponse.json({ error: "Unauthorized" }, { status: 401 })

    const body = await request.json()
    if (!body.id) return NextResponse.json({ error: "id required" }, { status: 400 })

    const fields: string[] = []
    const values: any[] = []
    let idx = 1

    const fieldMap: Record<string, string> = {
      fieldLabel: "field_label",
      fieldType: "field_type",
      options: "options",
      placeholder: "placeholder",
      defaultValue: "default_value",
      section: "section",
      isRequired: "is_required",
      sortOrder: "sort_order",
      isActive: "is_active",
    }

    for (const [key, col] of Object.entries(fieldMap)) {
      if (body[key] !== undefined) {
        fields.push(`${col} = $${idx++}`)
        values.push(key === "options" && body[key] ? JSON.stringify(body[key]) : body[key])
      }
    }

    if (fields.length === 0) return NextResponse.json({ error: "No fields to update" }, { status: 400 })

    fields.push(`updated_at = NOW()`)
    values.push(body.id)

    await query(`UPDATE custom_field_definitions SET ${fields.join(", ")} WHERE id = $${idx}`, values)
    return NextResponse.json({ success: true })
  } catch (error) {
    console.error("Custom fields PATCH error:", error)
    const message = error instanceof Error ? error.message : "Failed to update custom field"
    return NextResponse.json({ error: message }, { status: 500 })
  }
}

export async function DELETE(request: NextRequest) {
  try {
    await getSessionUser()
    const { searchParams } = new URL(request.url)
    const id = searchParams.get("id")
    if (!id) return NextResponse.json({ error: "id required" }, { status: 400 })
    await query("DELETE FROM custom_field_definitions WHERE id = $1", [id])
    return NextResponse.json({ success: true })
  } catch (error) {
    console.error("Custom fields DELETE error:", error)
    const message = error instanceof Error ? error.message : "Failed to delete custom field"
    return NextResponse.json({ error: message }, { status: 500 })
  }
}