import { JOB_STATUSES, type JobPageQuery, type JobStatus } from '@multi-simadmin/contracts';
import type { FastifyInstance, FastifyReply, FastifyRequest } from 'fastify';

import { JobQueryError, JobQueryService } from '../../application/jobs/job-query-service.js';
import {
  JobCancelError,
  JobReconcileService,
} from '../../application/jobs/job-reconcile-service.js';

export interface JobRoutesOptions {
  readonly jobs: JobQueryService;
  readonly reconcile?: JobReconcileService;
}

const QUERY_KEYS = new Set([
  'page',
  'pageSize',
  'sort',
  'direction',
  'status',
  'operationId',
  'rootJobId',
  'instanceId',
]);

const errorResponse = {
  VALIDATION_FAILED: {
    status: 400,
    title: 'Bad Request',
    detail: 'The jobs query is invalid.',
  },
  NOT_FOUND: {
    status: 404,
    title: 'Not Found',
    detail: 'The requested job does not exist.',
  },
  UNREPRESENTABLE: {
    status: 503,
    title: 'Service Unavailable',
    detail: 'The requested job data is temporarily unavailable.',
  },
} as const;

function invalid(): never {
  throw new JobQueryError('VALIDATION_FAILED', 'Invalid jobs query');
}

function parseQuery(query: unknown): JobPageQuery {
  if (query === null || typeof query !== 'object' || Array.isArray(query)) invalid();
  const input = query as Record<string, unknown>;
  for (const key of Object.keys(input)) {
    if (!QUERY_KEYS.has(key)) invalid();
    if (typeof input[key] !== 'string') invalid();
  }
  const scalar = (key: string): string | undefined => {
    const value = input[key];
    return value === undefined ? undefined : (value as string);
  };
  const integer = (key: 'page' | 'pageSize', fallback: number, maximum: number): number => {
    const value = scalar(key);
    if (value === undefined) return fallback;
    if (!/^[1-9]\d*$/u.test(value)) invalid();
    const parsed = Number(value);
    if (!Number.isSafeInteger(parsed) || parsed > maximum) invalid();
    return parsed;
  };

  const pageSize = integer('pageSize', 25, 100);
  const maximumPage = Math.floor(Number.MAX_SAFE_INTEGER / pageSize) + 1;
  const result: {
    page: number;
    pageSize: number;
    sort?: 'createdAt' | 'status' | 'operationId';
    direction: 'asc' | 'desc';
    status?: JobStatus;
    operationId?: string;
    rootJobId?: string;
    instanceId?: string;
  } = {
    page: integer('page', 1, maximumPage),
    pageSize,
    direction: 'asc',
  };

  const sort = scalar('sort');
  if (sort !== undefined) {
    if (sort !== 'createdAt' && sort !== 'status' && sort !== 'operationId') invalid();
    result.sort = sort;
  }
  const direction = scalar('direction');
  if (direction !== undefined) {
    if (direction !== 'asc' && direction !== 'desc') invalid();
    result.direction = direction;
  }
  const status = scalar('status');
  if (status !== undefined) {
    if (!(JOB_STATUSES as readonly string[]).includes(status)) invalid();
    result.status = status as JobStatus;
  }
  for (const key of ['operationId', 'rootJobId', 'instanceId'] as const) {
    const value = scalar(key);
    if (value !== undefined) {
      if (value.length === 0) invalid();
      result[key] = value;
    }
  }
  return result;
}

export function registerJobRoutes(app: FastifyInstance, options: JobRoutesOptions): void {
  const handler =
    <T>(action: (request: FastifyRequest) => T) =>
    async (request: FastifyRequest, reply: FastifyReply) => {
      try {
        return action(request);
      } catch (error) {
        if (!(error instanceof JobQueryError)) throw error;
        const mapped = errorResponse[error.code];
        return reply.code(mapped.status).type('application/problem+json').send({
          type: 'about:blank',
          title: mapped.title,
          status: mapped.status,
          code: error.code,
          detail: mapped.detail,
          requestId: request.id,
        });
      }
    };

  app.get(
    '/api/v1/jobs',
    handler((request) => options.jobs.list(parseQuery(request.query))),
  );
  app.get(
    '/api/v1/jobs/:jobId',
    handler((request) => options.jobs.get((request.params as { jobId: string }).jobId)),
  );

  const reconcile = options.reconcile;
  if (reconcile) {
    app.get('/api/v1/jobs/reconcile', async () => reconcile.summary());
    app.post('/api/v1/jobs/reconcile', () => reconcile.reconcile());

    app.post('/api/v1/jobs/:jobId/cancel', async (request, reply) => {
      const jobId = (request.params as { jobId: string }).jobId;
      try {
        reconcile.cancel(jobId);
      } catch (error) {
        if (!(error instanceof JobCancelError)) throw error;
        const mapped =
          error.code === 'NOT_FOUND'
            ? {
                status: 404,
                title: 'Not Found',
                detail: 'The requested job does not exist.',
              }
            : {
                status: 409,
                title: 'Conflict',
                detail: 'The job already reached a terminal state.',
              };
        return reply.code(mapped.status).type('application/problem+json').send({
          type: 'about:blank',
          title: mapped.title,
          status: mapped.status,
          code: error.code,
          detail: mapped.detail,
          requestId: request.id,
        });
      }
      return reply.code(202).send(options.jobs.get(jobId));
    });
  }
}