import type { FastifyInstance } from "fastify";
import type { PiProcessManager } from "../pi/pi-process-manager.js";
import type { ThtRunner } from "../tht/tht-runner.js";
import type { SseHub } from "../sse/sse-hub.js";
import type { Settings } from "../settings/settings-store.js";
import { getUser } from "../auth/auth.js";

export function sessionRoutes(
  app: FastifyInstance,
  d: { mgr: PiProcessManager; tht: ThtRunner; hub: SseHub; getSettings: () => Settings; ollamaEnsureTimeoutSec: number },
) {
  app.post("/sessions", async (req, reply) => {
    const b = req.body as { question: string; name?: string };
    const s = d.getSettings();
    const ensure = await d.tht.ollamaEnsure(s.workspace ?? "", d.ollamaEnsureTimeoutSec);
    if (!ensure.ok) return reply.code(503).send({ error: ensure.error ?? "Ollama/embeddings non disponibili" });
    // Settings (global) supply workspace/provider/model/thinking. The new-question
    // form sends only the question text. `workspace` selects the tht `-c <config>`.
    const { id } = await d.tht.sessionNew({
      question: b.question,
      name: b.name,
      workspace: s.workspace,
      provider: s.provider,
      model: s.model,
      thinking: s.thinking,
    });
    const rt = await d.mgr.spawnFor(id, {
      provider: s.provider,
      model: s.model,
      thinking: s.thinking,
      author: getUser(req).id,
    });
    rt.bridge.onClientEvent((e) => d.hub.publish(id, e.type, e));
    return { id };
  });
  app.get("/sessions", async () => d.tht.sessionList());
  app.get("/sessions/:id", async (req) => d.tht.sessionShow((req.params as any).id));
  app.post("/sessions/:id/response", async (req, reply) => {
    const id = (req.params as any).id;
    const rt = d.mgr.get(id);
    if (!rt) return reply.code(404).send({ error: "sessione non attiva" });
    rt.bridge.respond((req.body as any).ui_response);
    return reply.code(204).send();
  });
  app.post("/sessions/:id/steer", async (req, reply) => {
    const rt = d.mgr.get((req.params as any).id);
    if (!rt) return reply.code(404).send({ error: "sessione non attiva" });
    rt.bridge.steer((req.body as any).text);
    return reply.code(204).send();
  });
  app.post("/sessions/:id/resume", async (req, reply) => {
    const id = (req.params as any).id;
    const manifest = (await d.tht.sessionShow(id)) as { status?: string; archived?: boolean } | null;
    if (manifest?.status === "finalized" || manifest?.archived) {
      return reply.code(409).send({ error: "sessione in sola lettura (finalizzata o archiviata)" });
    }
    const ensure = await d.tht.ollamaEnsure(d.getSettings().workspace ?? "", d.ollamaEnsureTimeoutSec);
    if (!ensure.ok) return reply.code(503).send({ error: ensure.error ?? "Ollama/embeddings non disponibili" });
    const rt = await d.mgr.resume(id, d.tht);
    rt.bridge.onClientEvent((e) => d.hub.publish(id, e.type, e));
    return reply.code(200).send({ id });
  });
  app.post("/sessions/:id/close", async (req) => {
    d.mgr.teardown((req.params as any).id);
    return { closed: true };
  });
  app.get("/sessions/:id/events", (req, reply) => {
    const id = (req.params as any).id;
    const rt = d.mgr.get(id);
    // Add CORS headers manually: reply.raw.writeHead bypasses Fastify's onSend hooks
    // (where @fastify/cors injects headers), so we must set them explicitly here.
    const origin = (req.headers.origin as string | undefined) ?? "*";
    reply.raw.writeHead(200, {
      "Content-Type": "text/event-stream",
      "Cache-Control": "no-cache",
      Connection: "keep-alive",
      "Access-Control-Allow-Origin": origin,
      "Access-Control-Allow-Credentials": "true",
    });
    // Send the handshake immediately. Without this, Node waits for the first event body and
    // proxies/clients cannot establish an idle SSE subscription or inspect its headers.
    reply.raw.flushHeaders();
    const send = (event: string, data: object) => reply.raw.write(`event: ${event}\ndata: ${JSON.stringify(data)}\n\n`);
    const off = d.hub.subscribe(id, send, rt?.bridge.pendingWidget() ?? null);
    req.raw.on("close", off);
  });
  app.post("/sessions/:id/rename", async (req, reply) => {
    await d.tht.setName((req.params as any).id, (req.body as any).name);
    return reply.code(204).send();
  });
  app.post("/sessions/:id/group", async (req, reply) => {
    await d.tht.setGroup((req.params as any).id, (req.body as any).group);
    return reply.code(204).send();
  });
  app.post("/sessions/:id/archive", async (req, reply) => {
    await d.tht.archive((req.params as any).id);
    return reply.code(204).send();
  });
  app.post("/sessions/:id/unarchive", async (req, reply) => {
    await d.tht.unarchive((req.params as any).id);
    return reply.code(204).send();
  });
  app.delete("/sessions/:id", async (req, reply) => {
    const id = (req.params as any).id;
    d.mgr.teardown(id); // drop any live runtime before deleting on disk
    await d.tht.deleteSession(id);
    return reply.code(204).send();
  });
  app.get("/sessions/:id/documents", async (req) => d.tht.documents((req.params as any).id));
}