import type { FastifyInstance } from 'fastify';
import type { CreateSessionRequest, SessionResponse, SessionsListResponse } from '@arboretum/shared';
import type { PtyManager } from '../core/pty-manager.js';
import { mergeSessions, type DiscoveryService } from '../core/discovery-service.js';

export function registerSessionRoutes(app: FastifyInstance, manager: PtyManager, discovery: DiscoveryService): void {
  app.get('/api/v1/sessions', async (): Promise<SessionsListResponse> => {
    return { sessions: mergeSessions(manager.list(), discovery.list()) };
  });

  app.post('/api/v1/sessions', async (req, reply) => {
    const body = req.body as Partial<CreateSessionRequest> | null;
    if (!body || typeof body.cwd !== 'string' || !body.cwd.startsWith('/')) {
      return reply.status(400).send({ error: { code: 'BAD_REQUEST', message: 'cwd (absolute path) is required' } });
    }
    if (body.command !== undefined && body.command !== 'claude' && body.command !== 'bash') {
      return reply.status(400).send({ error: { code: 'BAD_REQUEST', message: 'command must be claude or bash' } });
    }
    try {
      const session = manager.spawn({ cwd: body.cwd, ...(body.command ? { command: body.command } : {}) });
      const res: SessionResponse = { session };
      return reply.status(201).send(res);
    } catch (err) {
      const statusCode = (err as { statusCode?: number }).statusCode ?? 500;
      return reply.status(statusCode).send({ error: { code: 'SPAWN_FAILED', message: (err as Error).message } });
    }
  });

  // Reprise d'une session morte : nouveau PTY managé `--resume <id>` DANS SON CWD D'ORIGINE (spike S1).
  // Le cwd n'est jamais fourni par le client : il est lu sur disque via la découverte.
  app.post('/api/v1/sessions/:id/resume', async (req, reply) => {
    const { id } = req.params as { id: string };
    const discovered = discovery.getDiscovered(id);
    if (!discovered) {
      return reply.status(404).send({ error: { code: 'NOT_FOUND', message: 'No resumable session with this id' } });
    }
    // Garde-fou anti-corruption : jamais de resume direct d'une session vivante (vérif FRAÎCHE).
    if (discovery.isClaudeSessionLive(id) || manager.findLiveByClaudeSessionId(id)) {
      return reply.status(409).send({ error: { code: 'SESSION_LIVE', message: 'Session is live — fork it instead' } });
    }
    try {
      // Session de groupe (P6) : re-relie les mêmes répertoires (--add-dir) et son groupe au resume.
      const ctx = manager.groupSessionContext(id);
      const session = manager.spawn({
        cwd: discovered.cwd,
        resume: { claudeSessionId: id },
        ...(ctx?.addedDirs.length ? { addDirs: ctx.addedDirs } : {}),
        ...(ctx?.groupId ? { groupId: ctx.groupId } : {}),
      });
      const res: SessionResponse = { session };
      return reply.status(201).send(res);
    } catch (err) {
      const statusCode = (err as { statusCode?: number }).statusCode ?? 500;
      return reply.status(statusCode).send({ error: { code: 'SPAWN_FAILED', message: (err as Error).message } });
    }
  });

  // Fork : duplique une session (vivante ou morte) sans la corrompre (`--resume <id> --fork-session`).
  app.post('/api/v1/sessions/:id/fork', async (req, reply) => {
    const { id } = req.params as { id: string };
    const discovered = discovery.getDiscovered(id);
    if (!discovered) {
      return reply.status(404).send({ error: { code: 'NOT_FOUND', message: 'No session with this id to fork' } });
    }
    try {
      const session = manager.spawn({ cwd: discovered.cwd, resume: { claudeSessionId: id, fork: true } });
      const res: SessionResponse = { session };
      return reply.status(201).send(res);
    } catch (err) {
      const statusCode = (err as { statusCode?: number }).statusCode ?? 500;
      return reply.status(statusCode).send({ error: { code: 'SPAWN_FAILED', message: (err as Error).message } });
    }
  });

  app.delete('/api/v1/sessions/:id', async (req, reply) => {
    const { id } = req.params as { id: string };
    if (!manager.kill(id)) {
      return reply.status(404).send({ error: { code: 'NOT_FOUND', message: 'No live session with this id' } });
    }
    return reply.send({ ok: true });
  });
}