import crypto from 'node:crypto';
import { Prisma } from '@vector/db';
import type {
  CreateWebhookSubscriptionRequest,
  UpdateWebhookSubscriptionRequest,
  WebhookEventName,
  WebhookSubscriptionListQuery,
} from '@vector/shared';
import { errors } from '../lib/http-error.js';
import type { Tx } from './types.js';

// The DB stores `events` as a JSON string (pending Postgres cutover to String[]).
// Parse on the way out, stringify on the way in. Keep this boundary in the service.
interface StoredSubscription {
  id: string;
  url: string;
  secret: string;
  events: string;
  active: boolean;
  createdAt: Date;
  updatedAt: Date;
}

export interface WebhookSubscriptionDto {
  id: string;
  url: string;
  events: WebhookEventName[];
  active: boolean;
  createdAt: string;
  updatedAt: string;
  // `secret` is returned only on create so operators can copy it into their receiver config.
  secret?: string;
}

function toDto(sub: StoredSubscription, includeSecret = false): WebhookSubscriptionDto {
  let events: WebhookEventName[] = [];
  try {
    const parsed = JSON.parse(sub.events);
    if (Array.isArray(parsed)) events = parsed as WebhookEventName[];
  } catch {
    events = [];
  }
  return {
    id: sub.id,
    url: sub.url,
    events,
    active: sub.active,
    createdAt: sub.createdAt.toISOString(),
    updatedAt: sub.updatedAt.toISOString(),
    ...(includeSecret ? { secret: sub.secret } : {}),
  };
}

export async function list(tx: Tx, q: WebhookSubscriptionListQuery) {
  const { page, pageSize, active } = q;
  const where: Prisma.WebhookSubscriptionWhereInput = {};
  if (active !== undefined) where.active = active;
  const [rows, total] = await Promise.all([
    tx.webhookSubscription.findMany({
      where,
      orderBy: { createdAt: 'desc' },
      skip: (page - 1) * pageSize,
      take: pageSize,
    }),
    tx.webhookSubscription.count({ where }),
  ]);
  return { data: rows.map((r) => toDto(r)), page, pageSize, total };
}

export async function create(tx: Tx, input: CreateWebhookSubscriptionRequest) {
  const secret = crypto.randomBytes(24).toString('base64url');
  const row = await tx.webhookSubscription.create({
    data: {
      url: input.url,
      secret,
      events: JSON.stringify(input.events),
      active: input.active ?? true,
    },
  });
  return toDto(row, true);
}

export async function update(tx: Tx, id: string, input: UpdateWebhookSubscriptionRequest) {
  const data: Prisma.WebhookSubscriptionUpdateInput = {};
  if (input.url !== undefined) data.url = input.url;
  if (input.events !== undefined) data.events = JSON.stringify(input.events);
  if (input.active !== undefined) data.active = input.active;
  try {
    const row = await tx.webhookSubscription.update({ where: { id }, data });
    return toDto(row);
  } catch (err) {
    if (err instanceof Prisma.PrismaClientKnownRequestError && err.code === 'P2025') {
      throw errors.notFound('WebhookSubscription');
    }
    throw err;
  }
}

export async function remove(tx: Tx, id: string) {
  try {
    await tx.webhookSubscription.delete({ where: { id } });
  } catch (err) {
    if (err instanceof Prisma.PrismaClientKnownRequestError && err.code === 'P2025') {
      throw errors.notFound('WebhookSubscription');
    }
    throw err;
  }
}

export async function rotateSecret(tx: Tx, id: string) {
  const secret = crypto.randomBytes(24).toString('base64url');
  try {
    const row = await tx.webhookSubscription.update({
      where: { id },
      data: { secret },
    });
    return toDto(row, true);
  } catch (err) {
    if (err instanceof Prisma.PrismaClientKnownRequestError && err.code === 'P2025') {
      throw errors.notFound('WebhookSubscription');
    }
    throw err;
  }
}

export async function listActiveForEvent(tx: Tx, event: WebhookEventName) {
  const rows = await tx.webhookSubscription.findMany({ where: { active: true } });
  return rows
    .map((r) => toDto(r, true))
    .filter((s) => s.events.includes(event));
}

export function signBody(secret: string, body: string, timestamp: number): string {
  return crypto
    .createHmac('sha256', secret)
    .update(`${timestamp}.${body}`)
    .digest('hex');
}