import { NextRequest, NextResponse } from "next/server";
import { z } from "zod";
import { admin, required } from "@/lib/supabase";
import { verifySupportWebhook } from "@/lib/support-signature";
import { supportCommand } from "@/shared/bug-reports";

export const runtime = "nodejs";
export async function POST(request: NextRequest) {
  const secret = process.env.LINEAR_WEBHOOK_SECRET;
  if (!secret)
    return NextResponse.json(
      { error: "Support integration is not configured" },
      { status: 503 },
    );
  const reader = request.body?.getReader();
  if (!reader) return new NextResponse(null, { status: 400 });
  const chunks: Uint8Array[] = [];
  let size = 0;
  while (true) {
    const { done, value } = await reader.read();
    if (done) break;
    size += value.length;
    if (size > 256 * 1024) {
      await reader.cancel();
      return new NextResponse(null, { status: 413 });
    }
    chunks.push(value);
  }
  const raw = Buffer.concat(chunks).toString("utf8");
  if (
    !verifySupportWebhook(raw, request.headers.get("linear-signature"), secret)
  )
    return new NextResponse(null, { status: 401 });
  let decoded: unknown;
  try {
    decoded = JSON.parse(raw);
  } catch {
    return new NextResponse(null, { status: 400 });
  }
  const payload = z
    .object({
      action: z.string(),
      type: z.string(),
      actor: z
        .object({
          id: z.string(),
          type: z.string(),
          name: z.string().optional(),
        })
        .nullable()
        .optional(),
      data: z.object({
        id: z.string().uuid(),
        issueId: z.string().uuid().optional(),
        body: z.string().optional(),
        userId: z.string().optional(),
      }),
    })
    .safeParse(decoded);
  if (!payload.success) return new NextResponse(null, { status: 400 });
  const event = payload.data;
  // Only explicit new staff comments are public. Internal comments and user echoes stay private.
  if (
    event.action !== "create" ||
    event.type !== "Comment" ||
    event.actor?.type.toLowerCase() !== "user" ||
    event.data.userId !== event.actor.id ||
    !event.data.issueId
  )
    return NextResponse.json({ ok: true });
  const command = supportCommand(event.data.body ?? "");
  if (!command) return NextResponse.json({ ok: true });
  try {
    required(
      await admin().rpc("receive_bug_reply", {
        p_report: event.data.issueId,
        p_external: event.data.id,
        p_author: event.actor.name ?? "Support",
        p_body: command.kind === "reply" ? command.text : "",
        p_glow: command.kind === "glow" ? command.enabled : null,
      }),
    );
    return NextResponse.json({ ok: true });
  } catch {
    return NextResponse.json(
      { error: "Support delivery failed" },
      { status: 503 },
    );
  }
}