import { createReadStream } from 'node:fs';

import type { FastifyInstance, FastifyReply, FastifyRequest } from 'fastify';

import type { SystemMaintenanceService } from '../../application/system/system-maintenance-service.js';
import type { ConnectionSettingsService } from '../../application/connections/connection-settings-service.js';
import type { FleetHeartbeatCoordinator } from '../../application/connections/fleet-heartbeat.js';
import {
  ComponentBackupError,
  type BackupComponentKey,
  type ComponentBackupService,
} from '../../application/system/component-backup-service.js';

export interface SystemRoutesOptions {
  readonly maintenance: SystemMaintenanceService;
  readonly componentBackups: ComponentBackupService;
  readonly connectionSettings: ConnectionSettingsService;
  /** Optional so a read-only deployment can omit the background beat. */
  readonly heartbeat?: FleetHeartbeatCoordinator;
}

function object(value: unknown): Record<string, unknown> {
  if (typeof value !== 'object' || value === null || Array.isArray(value))
    throw new TypeError('Request body must be an object');
  return value as Record<string, unknown>;
}

export function registerSystemRoutes(app: FastifyInstance, options: SystemRoutesOptions): void {
  const backups = () => options.componentBackups;
  const wrap =
    <T>(action: (request: FastifyRequest, reply: FastifyReply) => T | Promise<T>) =>
    async (request: FastifyRequest, reply: FastifyReply) => {
      try {
        return await action(request, reply);
      } catch (error) {
        if (error instanceof ComponentBackupError) {
          const status =
            error.code === 'NOT_FOUND'
              ? 404
              : error.code === 'INCOMPATIBLE' || error.code === 'INTEGRITY_FAILED'
                ? 422
                : 400;
          return reply
            .code(status)
            .type('application/problem+json')
            .send({
              type: 'about:blank',
              title:
                status === 404
                  ? 'Not Found'
                  : status === 422
                    ? 'Unprocessable Entity'
                    : 'Bad Request',
              status,
              code: `COMPONENT_BACKUP_${error.code}`,
              detail: 'The component backup request could not be completed.',
              requestId: request.id,
            });
        }
        if (error instanceof TypeError || error instanceof RangeError || error instanceof Error) {
          const invalid =
            error instanceof TypeError ||
            error instanceof RangeError ||
            /invalid|unknown|required/iu.test(error.message);
          if (!invalid) throw error;
          return reply.code(400).type('application/problem+json').send({
            type: 'about:blank',
            title: 'Bad Request',
            status: 400,
            code: 'MAINTENANCE_VALIDATION_FAILED',
            detail: 'The system maintenance request is invalid.',
            requestId: request.id,
          });
        }
        throw error;
      }
    };

  app.get(
    '/api/v1/system/maintenance',
    wrap(async () => options.maintenance.overview()),
  );
  app.get(
    '/api/v1/system/connection',
    wrap(async () => options.connectionSettings.get()),
  );
  app.put(
    '/api/v1/system/connection',
    wrap(async (request) => options.connectionSettings.update(request.body)),
  );
  app.post(
    '/api/v1/system/connection/refresh',
    wrap(async (request, reply) => {
      const beat = options.heartbeat;
      if (!beat)
        return reply.code(501).type('application/problem+json').send({
          type: 'about:blank',
          title: 'Not Implemented',
          status: 501,
          code: 'HEARTBEAT_UNAVAILABLE',
          detail: 'The device heartbeat is not enabled.',
          requestId: request.id,
        });
      return beat.runOnce();
    }),
  );
  app.put(
    '/api/v1/system/maintenance/retention',
    wrap(async (request) => options.maintenance.updateRetention(request.body)),
  );
  app.post(
    '/api/v1/system/maintenance/cleanup',
    wrap(async (request) => {
      const value = object(request.body).components;
      if (!Array.isArray(value) || value.length === 0) throw new TypeError('components is invalid');
      return options.maintenance.cleanup(value as never);
    }),
  );
  app.post(
    '/api/v1/system/maintenance/optimize',
    wrap(async () => options.maintenance.optimize()),
  );
  app.get(
    '/api/v1/system/maintenance/backups',
    wrap(async () => ({
      items: await options.maintenance.listBackups(),
    })),
  );
  app.post(
    '/api/v1/system/maintenance/backups',
    wrap(async (_request, reply) => reply.code(201).send(await options.maintenance.createBackup())),
  );
  app.get(
    '/api/v1/system/maintenance/backups/:filename',
    wrap(async (request, reply) => {
      const backup = await options.maintenance.backupFile(
        (request.params as { filename: string }).filename,
      );
      if (!backup)
        return reply.code(404).type('application/problem+json').send({
          type: 'about:blank',
          title: 'Not Found',
          status: 404,
          code: 'MAINTENANCE_BACKUP_NOT_FOUND',
          detail: 'The requested backup file no longer exists.',
          requestId: request.id,
        });
      reply
        .header('content-disposition', `attachment; filename="${backup.filename}"`)
        .header('content-length', String(backup.sizeBytes))
        .type('application/octet-stream');
      return createReadStream(backup.path);
    }),
  );
  app.delete(
    '/api/v1/system/maintenance/backups/:filename',
    wrap(async (request) =>
      options.maintenance.deleteBackup((request.params as { filename: string }).filename),
    ),
  );

  app.get(
    '/api/v1/system/component-backups/catalog',
    wrap(async () => ({ items: backups().catalog(), directory: backups().directory() })),
  );
  app.get(
    '/api/v1/system/component-backups/auto/settings',
    wrap(async () => backups().autoSettings()),
  );
  app.put(
    '/api/v1/system/component-backups/auto/settings',
    { bodyLimit: 8_192 },
    wrap(async (request) => backups().updateAutoSettings(request.body)),
  );
  app.post(
    '/api/v1/system/component-backups/auto/run',
    wrap(async () => ({ created: await backups().runDueAutoBackups() })),
  );
  app.get(
    '/api/v1/system/component-backups',
    wrap(async () => ({ items: await backups().list() })),
  );
  app.post(
    '/api/v1/system/component-backups',
    { bodyLimit: 8_192 },
    wrap(async (request, reply) => {
      const body = object(request.body);
      const created = await backups().create(
        body.components as readonly BackupComponentKey[],
        body.note,
      );
      return reply.code(201).send(created);
    }),
  );
  app.get(
    '/api/v1/system/component-backups/:filename/preview',
    wrap(async (request) => backups().preview((request.params as { filename: string }).filename)),
  );
  app.get(
    '/api/v1/system/component-backups/:filename/download',
    wrap(async (request, reply) => {
      const backup = await backups().backupFile((request.params as { filename: string }).filename);
      if (!backup)
        return reply.code(404).type('application/problem+json').send({
          type: 'about:blank',
          title: 'Not Found',
          status: 404,
          code: 'COMPONENT_BACKUP_NOT_FOUND',
          detail: 'The requested component backup file no longer exists.',
          requestId: request.id,
        });
      reply
        .header('content-disposition', `attachment; filename="${backup.filename}"`)
        .header('content-length', String(backup.sizeBytes))
        .type('application/octet-stream');
      return createReadStream(backup.path);
    }),
  );
  app.post(
    '/api/v1/system/component-backups/:filename/restore',
    { bodyLimit: 8_192 },
    wrap(async (request) =>
      backups().restore(
        (request.params as { filename: string }).filename,
        object(request.body).components as readonly BackupComponentKey[],
      ),
    ),
  );
  app.delete(
    '/api/v1/system/component-backups/:filename',
    wrap(async (request) => backups().remove((request.params as { filename: string }).filename)),
  );
}