import Fastify, { type FastifyInstance } from "fastify";
import cors from "@fastify/cors";
import type { AppConfig } from "./config.js";
import { ThtRunner } from "./tht/tht-runner.js";
import { PiProcessManager } from "./pi/pi-process-manager.js";
import { SseHub } from "./sse/sse-hub.js";
import { authPreHandler } from "./auth/auth.js";
import { getPrincipal } from "./auth/auth.js";
import type { PrincipalContext } from "./auth/principal.js";
import { sessionRoutes } from "./routes/sessions.js";
import { sqlRoutes } from "./routes/sql.js";
import { metaRoutes, type ListModelsFn } from "./routes/meta.js";
import { settingsRoutes, effectiveSettings } from "./routes/settings.js";
import { createPiModelLister } from "./pi/list-models.js";
import { loadSettings, saveSettings, type Settings } from "./settings/settings-store.js";
import { ReadinessManager } from "./runtime/readiness-manager.js";

export interface BuildAppDeps {
  thtRunner?: ThtRunner;
  mgr?: PiProcessManager;
  spawnFn?: () => any;
  listModels?: ListModelsFn;
  getSettings?: (principal?: PrincipalContext) => Settings | Promise<Settings>;
  readiness?: ReadinessManager;
  hub?: SseHub;
}

export function buildApp(config: AppConfig, deps?: BuildAppDeps): FastifyInstance {
  const app = Fastify({ logger: { level: "warn" }, disableRequestLogging: true });

  // Allow any origin in dev/e2e; tighten in production via config if needed.
  app.register(cors, {
    origin: true,
    credentials: true,
    methods: ["GET", "POST", "PUT", "DELETE", "OPTIONS"],
  });

  const tht = deps?.thtRunner ?? new ThtRunner({
    thtBin: config.thtBin,
    harnessDir: config.harnessDir,
    configPath: process.env.THT_CONFIG ?? "config/tht.yaml",
    dataRoot: config.dataRoot,
    secretsFile: config.secretsFile,
    secretFiles: config.secretFiles,
  });
  const mgr = deps?.mgr ?? new PiProcessManager(config, deps?.spawnFn ? { spawnFn: deps.spawnFn } : undefined);
  const hub = deps?.hub ?? new SseHub();
  const readiness = deps?.readiness ?? new ReadinessManager(
    tht as ThtRunner,
    Math.round(config.ollamaEnsureTimeoutMs / 1000),
  );

  const listModels = deps?.listModels ?? createPiModelLister(config, {
    warn: (detail) => app.log.warn(
      { component: "pi-model-list", detail },
      "Pi enabled-model configuration warning",
    ),
  });
  const runnerFor = (principal: PrincipalContext): any => {
    const candidate = tht as any;
    return typeof candidate.withPrincipal === "function" ? candidate.withPrincipal(principal) : candidate;
  };
  const getSettings = async (principal: PrincipalContext): Promise<Settings> => {
    if (deps?.getSettings) return await deps.getSettings(principal);
    const runner = runnerFor(principal);
    // The real runner persists preferences through the harness repository. The file fallback
    // only keeps older isolated route tests and externally injected runners compatible.
    if (typeof runner.preferencesGet === "function") {
      const stored = await runner.preferencesGet() as Settings;
      if (Object.keys(stored).length === 0) {
        const seeded = effectiveSettings(config, loadSettings(config));
        await runner.preferencesSet(seeded);
        return seeded;
      }
      return effectiveSettings(config, stored);
    }
    return effectiveSettings(config, loadSettings(config));
  };
  const saveUserSettings = async (principal: PrincipalContext, settings: Settings): Promise<void> => {
    const runner = runnerFor(principal);
    if (typeof runner.preferencesSet === "function") {
      await runner.preferencesSet(settings);
      return;
    }
    saveSettings(config, settings);
  };

  const authenticate = authPreHandler(config.authMode);
  app.addHook("preHandler", async (req, reply) => {
    // Process readiness is intentionally unauthenticated for local container/proxy probes.
    if (req.url === "/health" || req.url === "/health/dwh") return;
    return authenticate(req, reply);
  });
  app.get("/health", async () => ({ status: "ok" }));
  app.get("/health/dwh", async () => tht.dbPing());
  app.get("/me", async (req) => getPrincipal(req));
  sessionRoutes(app, {
    mgr, tht: tht as ThtRunner, hub, getSettings, readiness, dwhPrecheck: config.dwhPrecheck,
  });
  sqlRoutes(app, { tht: tht as ThtRunner, getSettings });
  metaRoutes(app, { harnessDir: config.harnessDir, listModels });
  settingsRoutes(app, { cfg: config, listModels, getSettings, saveSettings: saveUserSettings });

  return app;
}