/**
 * GET /api/data?cid=<cid>&cs=<cs>
 *
 * Verifies the checksum, resolves the org from the contact via the
 * Primary Form Contact relationship, reads the org's Framework Stage,
 * and walks past Org Engagement Submission activities for per-field
 * most-recent prefill.
 *
 * Returns FormDataPayload (see types/form.ts).
 *
 * STUB MODE: if CiviCRM env vars are unset, returns mock data so the UI
 * is exercisable without a live CRM. The mock data uses the actual stage
 * values and a couple of populated example fields so the form looks alive
 * during development.
 */

import { NextRequest, NextResponse } from "next/server";
import { civi, verifyChecksum } from "@/lib/civicrm";
import { loadPrefill } from "@/lib/prefill";
import { allFields } from "@/config/form";
import type { FormDataPayload } from "@/types/form";

const STUB_PAYLOAD: FormDataPayload = {
  orgName: "Sample Co-op (stub)",
  currentStage: "Organizing",
  prefill: {
    stage_0_peer_group_participation: "Peer cohort 4",
    stage_0_members_current: 87,
    stage_0_total_members_at_opening: null,
    stage_0_projected_y1_sales: 2400000,
    stage_0_projected_y2_sales: 2950000,
    stage_0_total_cost_of_project: 4200000,
    stage_1_vision: "A neighborhood-rooted co-op grocery prioritizing local farmers and equity in food access.",
    stage_1_business_concept: "5,500 sq ft full-service co-op in a transit-adjacent storefront.",
  },
};

function isStubMode(): boolean {
  return !(
    process.env.CIVI_BASE_URL &&
    process.env.CIVI_API_KEY &&
    process.env.CIVI_SITE_KEY
  );
}

export async function GET(req: NextRequest) {
  const url = new URL(req.url);
  const cid = url.searchParams.get("cid");
  const cs = url.searchParams.get("cs");

  if (!cid || !cs) {
    return NextResponse.json(
      { error: "Missing cid or cs parameter." },
      { status: 400 },
    );
  }

  if (isStubMode()) {
    return NextResponse.json(STUB_PAYLOAD);
  }

  // Verify checksum first.
  const ok = await verifyChecksum(cid, cs);
  if (!ok) {
    return NextResponse.json(
      { error: "Link is invalid or has expired. Please request a fresh one." },
      { status: 401 },
    );
  }

  // Resolve the org from the contact's Primary Form Contact relationship.
  // Requires that the relationship exists and is active. We fetch contact_id_b
  // because the relationship is Individual (A) → Organization (B).
  const relRes = await civi<{ contact_id_b: number }>("Relationship", "get", {
    select: ["contact_id_b"],
    where: [
      ["contact_id_a", "=", Number(cid)],
      ["relationship_type_id:name", "=", "Primary Form Contact of"],
      ["is_active", "=", true],
    ],
    limit: 2,
  });
  const orgs = relRes.values ?? [];
  if (orgs.length === 0) {
    return NextResponse.json(
      { error: "No active Primary Form Contact relationship found for your contact." },
      { status: 404 },
    );
  }
  if (orgs.length > 1) {
    return NextResponse.json(
      { error: "Your contact has multiple active Primary Form Contact relationships; staff must resolve before this link will work." },
      { status: 409 },
    );
  }
  const orgId = orgs[0].contact_id_b;

  // Fetch org name + Framework Stage value.
  const orgRes = await civi<{
    id: number;
    display_name: string;
    "Food_Co_op_Organizing.Stage": string | null;
    custom_1?: string | null;
  }>("Contact", "get", {
    select: ["id", "display_name", "custom_1", "Food_Co_op_Organizing.Stage"],
    where: [["id", "=", orgId]],
  });
  const org = orgRes.values?.[0];
  if (!org) {
    return NextResponse.json({ error: "Organization not found." }, { status: 404 });
  }
  const currentStage =
    org["Food_Co_op_Organizing.Stage"] ?? org.custom_1 ?? "";

  // Per-field-most-recent prefill across past submission activities.
  const { values: prefill } = await loadPrefill(orgId, allFields);

  const payload: FormDataPayload = {
    orgName: org.display_name,
    currentStage: typeof currentStage === "string" ? currentStage : "",
    prefill,
  };
  return NextResponse.json(payload);
}