/**
 * POST /api/submit
 *
 * Body: SubmitPayload { cid, cs, values }.
 *
 * Verifies checksum, resolves org from cid (mirror of /api/data), then
 * creates a new `Check-in (organizing)` activity. The activity's own Stage
 * field is intentionally left null: the form is not the authority on stage.
 * Staff set Stage on their own check-in activities to mark transitions, and
 * /api/data derives the org's current stage from the most recent stage-
 * bearing activity.
 *
 * STUB MODE: if CiviCRM env vars are unset, returns success without writing.
 */

import { NextResponse } from "next/server";
import { civi, verifyChecksum } from "@/lib/civicrm";
import { allFields, ACTIVITY_TYPE_NAME, FORM_CONTACT_RELATIONSHIP } from "@/config/form";
import type { SubmitPayload } from "@/types/form";
import { appEnv, redact } from "@/lib/env";
import { rateLimit, clientIp } from "@/lib/rate-limit";

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

const FIELD_BY_NAME = new Map(allFields.map((f) => [f.name, f]));

export async function POST(req: Request) {
  // Rate limit per client IP. Generous default — 10 submissions per minute.
  const ip = clientIp(req);
  const rl = rateLimit(`submit:${ip}`, { capacity: 10, windowMs: 60_000 });
  if (!rl.allowed) {
    return NextResponse.json(
      { error: "Too many submissions. Please wait a moment and try again." },
      {
        status: 429,
        headers: {
          "Retry-After": String(Math.ceil(rl.resetMs / 1000)),
        },
      },
    );
  }

  let body: SubmitPayload;
  try {
    body = (await req.json()) as SubmitPayload;
  } catch {
    return NextResponse.json({ error: "Malformed JSON body." }, { status: 400 });
  }
  const { cid, cs, values } = body;
  if (!cid || !cs) {
    return NextResponse.json({ error: "Missing cid or cs." }, { status: 400 });
  }

  if (isStubMode()) {
    console.warn("[submit:STUB] would create Check-in (organizing) activity with values:", values);
    return NextResponse.json({ ok: true, stub: true });
  }

  try {
    return await runSubmit(cid, cs, values);
  } catch (err) {
    const msg = err instanceof Error ? err.message : String(err);
    console.error("[submit] failure:", redact(msg));
    return NextResponse.json(
      {
        error: appEnv().isProduction
          ? "Could not save your survey. Please try again, or contact <a href=\"mailto:chris@fci.coop\">Chris @ FCI</a>."
          : `Save failed: ${redact(msg)}`,
      },
      { status: 500 },
    );
  }
}

async function runSubmit(cid: string, cs: string, values: Record<string, unknown>): Promise<NextResponse> {
  const ok = await verifyChecksum(cid, cs);
  if (!ok) {
    return NextResponse.json({ error: "Link is invalid or has expired." }, { status: 401 });
  }

  // Resolve org via the relationship (mirror of /api/data).
  const relRes = await civi<{ contact_id_b: number }>("Relationship", "get", {
    select: ["contact_id_b"],
    where: [
      ["contact_id_a", "=", Number(cid)],
      ["relationship_type_id.name_a_b", "=", FORM_CONTACT_RELATIONSHIP],
      ["is_active", "=", true],
    ],
    limit: 2,
  });
  const orgs = relRes.values ?? [];
  if (orgs.length !== 1) {
    return NextResponse.json(
      { error: "Could not resolve a unique organization for your contact." },
      { status: orgs.length === 0 ? 404 : 409 },
    );
  }
  const orgId = orgs[0].contact_id_b;

  // Split incoming values into:
  //   - activityRecord: fields with civiField → written to the new activity
  //   - orgContactValues: fields with civiContactField → written to the org
  //                       contact via Contact.update
  // Readonly fields are skipped entirely (display-only).
  const activityRecord: Record<string, unknown> = {
    "activity_type_id:name": ACTIVITY_TYPE_NAME,
    "status_id:name": "Completed",
    target_contact_id: orgId,
    source_contact_id: Number(cid),
    subject: "Co-op Survey (form submission)",
  };
  const orgContactValues: Record<string, unknown> = {};
  for (const [name, value] of Object.entries(values)) {
    const field = FIELD_BY_NAME.get(name);
    if (!field) continue;
    if (field.type === "readonly") continue; // never write read-only fields

    // File fields: the renderer uploads to /api/upload on file-pick and
    // stores {id, file_name} in form state. Submit only needs the id —
    // that's what Civi stores in the custom column. If the user left a
    // prior attachment alone, we receive the same prefill shape and
    // still write the same id (no-op effectively).
    let civiValue: unknown = value;
    if (field.type === "file" && value && typeof value === "object" && !Array.isArray(value)) {
      const v = value as { id?: unknown };
      civiValue = typeof v.id === "number" || typeof v.id === "string" ? v.id : null;
    }

    if (field.civiContactField) {
      orgContactValues[field.civiContactField] = civiValue;
    } else if (field.civiField) {
      activityRecord[field.civiField] = civiValue;
    }
  }

  // Update the org contact first (if any contact-bound fields changed),
  // then create the submission activity. Order matters: if the contact
  // update fails we'd rather not have an orphan activity claiming the
  // submission succeeded.
  if (Object.keys(orgContactValues).length > 0) {
    await civi("Contact", "update", {
      where: [["id", "=", orgId]],
      values: orgContactValues,
    });
  }

  await civi("Activity", "create", { values: activityRecord });

  return NextResponse.json({ ok: true });
}