import type { FastifyInstance } from "fastify";
import type { AppConfig } from "../config.js";
import type { Settings } from "../settings/settings-store.js";
import { listWorkspaces } from "./meta.js";
import type { PrincipalContext } from "../auth/principal.js";
import { isPrincipalContext, requirePermission } from "../auth/authorization.js";
import {
  splitCanonicalModelId,
  type RuntimeModelCatalog,
} from "../models/runtime-model-catalog.js";

/** Merge only workspace and runtime-thinking preferences; model defaults belong to modelCatalog. */
export function effectiveSettings(
  cfg: AppConfig,
  stored: Settings,
  modelCatalog?: RuntimeModelCatalog,
): Settings {
  const workspaces = listWorkspaces(cfg.harnessDir);
  const selected = modelCatalog?.defaultInteraction
    ? splitCanonicalModelId(modelCatalog.defaultInteraction)
    : undefined;
  return {
    workspace: stored.workspace ?? workspaces[0]?.name,
    ...(selected ?? {}),
    thinking: cfg.defaults.thinking ?? stored.thinking,
  };
}

export function settingsRoutes(
  app: FastifyInstance,
  deps: {
    cfg: AppConfig;
    getSettings: (principal: PrincipalContext) => Promise<Settings>;
  },
): void {
  app.get("/settings", async (req, reply) => {
    const principal = requirePermission(req, reply, "session.use");
    if (!isPrincipalContext(principal)) return principal;
    try {
      return await deps.getSettings(principal);
    } catch {
      return reply.code(503).send({ error: "settings storage is unavailable" });
    }
  });

  app.put("/settings", async (req, reply) => {
    const principal = requirePermission(req, reply, "settings.manage");
    if (!isPrincipalContext(principal)) return principal;
    const b = (req.body ?? {}) as Settings;
    try {
      // Retain this endpoint as a validating compatibility surface for older clients, but do
      // not write anonymous users' choices to shared server storage.
      return await deps.getSettings(principal);
    } catch {
      return reply.code(503).send({ error: "settings storage is unavailable" });
    }
  });
}