import { env } from "@code/env/convex";
import {
  isProcessedEvent,
  MAX_WEBHOOK_PAYLOAD_BYTES,
} from "@code/primitives/git-webhook";
import { makeFunctionReference } from "convex/server";

import type { Id } from "./_generated/dataModel";
import { httpAction } from "./_generated/server";

const recordWebhookDeliveryRef = makeFunctionReference<
  "mutation",
  {
    deliveryId: string;
    event: string;
    externalRepositoryId?: string;
    payloadHash: string;
    provider: "github" | "gitea";
  },
  { deliveryId: Id<"gitWebhookDeliveries">; duplicate: boolean }
>("gitProvisioning:recordWebhookDelivery");
const resolveRepositoryByExternalIdRef = makeFunctionReference<
  "query",
  {
    externalRepositoryId: string;
    provider: "github" | "gitea";
  },
  { _id: Id<"gitRepositories"> } | null
>("gitProvisioning:resolveRepositoryByExternalId");
const markDeliveryProcessedRef = makeFunctionReference<
  "mutation",
  {
    deliveryId: Id<"gitWebhookDeliveries">;
    repositoryRef?: Id<"gitRepositories">;
  },
  null
>("gitProvisioning:markDeliveryProcessed");

/* eslint-disable @typescript-eslint/no-explicit-any -- action ctx type is complex without codegen */
const processDelivery = async (
  ctx: any,
  input: {
    readonly deliveryId: string;
    readonly event: string;
    readonly externalRepositoryId?: string;
    readonly payloadHash: string;
    readonly provider: "github" | "gitea";
  }
): Promise<{ deliveryId: string; duplicate: boolean }> => {
  const result: { deliveryId: Id<"gitWebhookDeliveries">; duplicate: boolean } =
    await ctx.runMutation(recordWebhookDeliveryRef, input);
  if (result.duplicate) {
    return result;
  }
  // Resolve the repository reference if we have an external ID.
  let repositoryRef: Id<"gitRepositories"> | undefined;
  if (input.externalRepositoryId) {
    const repo = await ctx.runQuery(resolveRepositoryByExternalIdRef, {
      externalRepositoryId: input.externalRepositoryId,
      provider: input.provider,
    });
    if (repo) {
      repositoryRef = repo._id as Id<"gitRepositories">;
    }
  }
  await ctx.runMutation(markDeliveryProcessedRef, {
    deliveryId: result.deliveryId,
    ...(repositoryRef ? { repositoryRef } : {}),
  });
  return result;
};

const verifyHmacSignature = async (
  body: string,
  signature: string,
  secret: string,
  algorithm: "sha256" | "sha1"
): Promise<boolean> => {
  const key = await crypto.subtle.importKey(
    "raw",
    new TextEncoder().encode(secret),
    { hash: algorithm, name: "HMAC" },
    false,
    ["verify"]
  );
  let sigHex = signature;
  if (signature.startsWith("sha256=")) {
    sigHex = signature.slice(7);
  } else if (signature.startsWith("sha1=")) {
    sigHex = signature.slice(5);
  }
  const sigBytes = new Uint8Array(
    sigHex.match(/.{2}/gu)?.flatMap((byte) => Number.parseInt(byte, 16)) ?? []
  );
  return await crypto.subtle.verify(
    "HMAC",
    key,
    sigBytes,
    new TextEncoder().encode(body)
  );
};

const hashPayload = async (body: string): Promise<string> => {
  const digest = await crypto.subtle.digest(
    "SHA-256",
    new TextEncoder().encode(body)
  );
  return [...new Uint8Array(digest)]
    .map((byte) => byte.toString(16).padStart(2, "0"))
    .join("");
};

export const githubWebhook = httpAction(async (ctx, request) => {
  const deliveryId = request.headers.get("x-github-delivery") ?? "";
  const event = request.headers.get("x-github-event") ?? "";
  const signature = request.headers.get("x-hub-signature-256") ?? "";

  if (!deliveryId || !event) {
    return new Response("Missing GitHub delivery headers", { status: 400 });
  }

  const rawBody = await request.text();

  const payloadBytes = new TextEncoder().encode(rawBody).length;
  if (payloadBytes > MAX_WEBHOOK_PAYLOAD_BYTES) {
    return new Response("Payload too large", { status: 413 });
  }

  if (!env.GITHUB_WEBHOOK_SECRET) {
    return new Response("GitHub webhook secret not configured", {
      status: 500,
    });
  }
  const valid = await verifyHmacSignature(
    rawBody,
    signature,
    env.GITHUB_WEBHOOK_SECRET,
    "sha256"
  );
  if (!valid) {
    return new Response("Invalid signature", { status: 401 });
  }

  if (!isProcessedEvent(event)) {
    return new Response("Event ignored", { status: 200 });
  }

  const payload = JSON.parse(rawBody) as {
    action?: string;
    repository?: {
      full_name: string;
      html_url: string;
      id: number;
      name: string;
      owner: { login: string };
    };
  };

  const externalRepositoryId = payload.repository
    ? String(payload.repository.id)
    : undefined;

  const payloadHash = await hashPayload(rawBody);

  // Persist delivery, resolve repository, and mark processed.
  const result = await processDelivery(ctx, {
    deliveryId,
    event,
    externalRepositoryId,
    payloadHash,
    provider: "github",
  });

  return Response.json({
    deliveryId,
    duplicate: result.duplicate,
    event,
    externalRepositoryId,
    payloadHash,
    processed: true,
    provider: "github",
  });
});

export const puterWebhook = httpAction(async (ctx, request) => {
  const deliveryId = request.headers.get("x-gitea-delivery") ?? "";
  const event = request.headers.get("x-gitea-event") ?? "";
  const signature = request.headers.get("x-gitea-signature") ?? "";

  if (!deliveryId || !event) {
    return new Response("Missing Gitea delivery headers", { status: 400 });
  }

  const rawBody = await request.text();

  const payloadBytes = new TextEncoder().encode(rawBody).length;
  if (payloadBytes > MAX_WEBHOOK_PAYLOAD_BYTES) {
    return new Response("Payload too large", { status: 413 });
  }

  if (!env.GITEA_WEBHOOK_SECRET) {
    return new Response("Gitea webhook secret not configured", { status: 500 });
  }
  const valid = await verifyHmacSignature(
    rawBody,
    signature,
    env.GITEA_WEBHOOK_SECRET,
    "sha256"
  );
  if (!valid) {
    return new Response("Invalid signature", { status: 401 });
  }

  if (!isProcessedEvent(event)) {
    return new Response("Event ignored", { status: 200 });
  }

  const payload = JSON.parse(rawBody) as {
    action?: string;
    repository?: {
      full_name: string;
      html_url: string;
      id: number;
      name: string;
      owner: { login: string };
    };
  };

  const externalRepositoryId = payload.repository
    ? String(payload.repository.id)
    : undefined;

  const payloadHash = await hashPayload(rawBody);

  const result = await processDelivery(ctx, {
    deliveryId,
    event,
    externalRepositoryId,
    payloadHash,
    provider: "gitea",
  });

  return Response.json({
    deliveryId,
    duplicate: result.duplicate,
    event,
    externalRepositoryId,
    payloadHash,
    processed: true,
    provider: "gitea",
  });
});