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

function stageStatus(name: string): string {
  switch (name) {
    case "New": return "open"
    case "Contacted": return "contacted"
    case "Qualified":
    case "Interested":
    case "Demo Scheduled":
    case "Negotiation": return "pending"
    case "Closed Won": return "closed"
    case "Closed Lost": return "ignored"
    default: return "open"
  }
}

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

    const isAdmin = user.role === "admin" || user.role === "super_admin"

    const result = await query(
      `SELECT ls.id, ls.name, ls.sort_order, ls.probability,
              COALESCE(
                json_agg(
                  json_build_object(
                    'id', l.id,
                    'company_name', l.company_name,
                    'contact_name', l.contact_name,
                    'email', l.email,
                    'phone', l.phone,
                    'score', l.score,
                    'notes', l.notes,
                    'assigned_to', l.assigned_to,
                    'created_at', l.created_at
                  )
                  ORDER BY l.created_at DESC
                ) FILTER (WHERE l.id IS NOT NULL),
                '[]'::json
              ) AS leads
       FROM lead_stages ls
       LEFT JOIN leads l ON l.stage_id = ls.id AND l.deleted_at IS NULL
       WHERE ls.is_active = true
       GROUP BY ls.id, ls.name, ls.sort_order, ls.probability
       ORDER BY ls.sort_order`
    )

    const columns = result.rows.map((r: any) => {
      const status = stageStatus(r.name)
      let leads = r.leads || []
      if (!isAdmin) {
        leads = leads.filter((l: any) => l.assigned_to === user.id)
      }
      return {
        id: r.id,
        name: r.name,
        status,
        sortOrder: r.sort_order,
        probability: r.probability,
        leads,
      }
    })

    return NextResponse.json(columns)
  } catch (error) {
    console.error("Kanban API error:", error)
    const message = error instanceof Error ? error.message : "Failed to load kanban data"
    return NextResponse.json({ error: message }, { status: 500 })
  }
}