import { NextRequest, NextResponse } from "next/server";
import { prisma } from "@/lib/db";
import { Prisma } from "@prisma/client";

export async function GET(req: NextRequest) {
  try {
    const { searchParams } = new URL(req.url);
    const search = searchParams.get("search") || "";
    const statuses = searchParams.getAll("status");
    const sourceTabs = searchParams.getAll("sourceTab");
    const priorities = searchParams.getAll("priority");
    const hasEmail = searchParams.get("hasEmail");
    const emailOnly = searchParams.get("emailOnly") === "true";

    const where: Prisma.LeadWhereInput = {};
    if (search) {
      where.OR = [
        { domain: { contains: search } },
        { companyName: { contains: search } },
        { contactName: { contains: search } },
        { email: { contains: search } },
      ];
    }
    if (statuses.length > 0) where.status = { in: statuses };
    if (sourceTabs.length > 0) where.sourceTab = { in: sourceTabs };
    if (priorities.length > 0) where.priority = { in: priorities };
    if (hasEmail === "yes" || emailOnly) where.email = { not: null };
    else if (hasEmail === "no") where.email = null;

    const leads = await prisma.lead.findMany({
      where,
      orderBy: { capturedAt: "desc" },
      take: 10000,
    });

    const columns = [
      "status", "priority", "company_name", "domain", "contact_name",
      "contact_title", "email", "email_confidence", "linkedin_url", "phone",
      "source_tab", "source_term", "tags", "country", "headcount", "industry",
      "notes", "captured_at", "contacted_at", "serp_rank", "serp_url",
      "serp_title", "serp_snippet", "lead_id",
    ];

    const rows = leads.map(l => ({
      status: l.status,
      priority: l.priority,
      company_name: l.companyName || "",
      domain: l.domain || "",
      contact_name: l.contactName || "",
      contact_title: l.contactTitle || "",
      email: l.email || "",
      email_confidence: l.emailConfidence != null ? Math.round(l.emailConfidence * 100) + "%" : "",
      linkedin_url: l.linkedinUrl || "",
      phone: l.phone || "",
      source_tab: l.sourceTab,
      source_term: l.sourceTerm || "",
      tags: l.tags || "",
      country: l.country || "",
      headcount: l.headcount || "",
      industry: l.industry || "",
      notes: l.notes || "",
      captured_at: l.capturedAt.toISOString(),
      contacted_at: l.contactedAt?.toISOString() || "",
      serp_rank: l.serpRank?.toString() || "",
      serp_url: l.serpUrl || "",
      serp_title: l.serpTitle || "",
      serp_snippet: l.serpSnippet || "",
      lead_id: l.id,
    }));

    const csv = [
      columns.join(","),
      ...rows.map(r =>
        columns.map(c => {
          const v = String(r[c as keyof typeof r] || "");
          return v.includes(",") || v.includes('"') || v.includes("\n")
            ? `"${v.replace(/"/g, '""')}"`
            : v;
        }).join(",")
      ),
    ].join("\n");

    return new NextResponse(csv, {
      headers: {
        "Content-Type": "text/csv; charset=utf-8",
        "Content-Disposition": `attachment; filename="leadflow-vault-${new Date().toISOString().split("T")[0]}.csv"`,
      },
    });
  } catch (err) {
    console.error("GET /api/leads/export error:", err);
    return NextResponse.json({ error: "Export failed" }, { status: 500 });
  }
}