import { join, resolve } from "node:path";
import {
  AuthStorage,
  DefaultResourceLoader,
  ModelRegistry,
  SessionManager,
  SettingsManager,
  createAgentSession,
  getAgentDir,
  type AgentSession,
  type ResourceLoader,
} from "@earendil-works/pi-coding-agent";
import { getModel } from "@earendil-works/pi-ai";
import type { Client } from "discord.js";
import { createScheduleTools } from "./tools/schedule.js";

const PROVIDER = process.env.DISCLAW_PROVIDER ?? "anthropic";
const MODEL_ID = process.env.DISCLAW_MODEL ?? "claude-sonnet-4-6";
const TZ = process.env.TZ ?? "UTC";

export interface SharedDeps {
  authStorage: AuthStorage;
  modelRegistry: ModelRegistry;
  model: ReturnType<typeof getModel>;
  resourceLoader: ResourceLoader;
  settingsManager: SettingsManager;
  cwd: string;
  schedulesDir: string;
  /** Called whenever a schedule file is created or removed. */
  onSchedulesChanged?: () => void;
}

export interface SessionContext {
  /** Discord channel ID to use as default destination for schedule_task. */
  defaultDestination?: string;
  /** Discord user ID to use as DM fallback for schedule_task. */
  defaultUserId?: string;
}

export interface CreateSessionOptions {
  sessionManager?: SessionManager;
}

export async function createSharedDeps(
  opts: { onSchedulesChanged?: () => void } = {}
): Promise<SharedDeps> {
  const cwd = resolve(process.cwd());
  const authStorage = AuthStorage.create();
  const modelRegistry = ModelRegistry.create(authStorage);
  const model = getModel(PROVIDER as never, MODEL_ID as never);
  if (!model) {
    throw new Error(
      `Model not found: ${PROVIDER}/${MODEL_ID}. Set ANTHROPIC_API_KEY (or DISCLAW_PROVIDER/DISCLAW_MODEL).`
    );
  }
  const settingsManager = SettingsManager.create(cwd, getAgentDir());
  const resourceLoader = new DefaultResourceLoader({
    cwd,
    agentDir: getAgentDir(),
    settingsManager,
    additionalSkillPaths: [resolve(cwd, "skills")],
    appendSystemPromptOverride: (base) => [
      ...base,
      `The user's local timezone is ${TZ}. Always reference and display times, dates, and schedules in this timezone unless the user explicitly requests a different one.`,
    ],
  });
  await resourceLoader.reload();
  return {
    authStorage,
    modelRegistry,
    model,
    resourceLoader,
    settingsManager,
    cwd,
    schedulesDir: join(cwd, "memory", "schedules"),
    onSchedulesChanged: opts.onSchedulesChanged,
  };
}

export async function createSession(
  deps: SharedDeps,
  ctx: SessionContext = {},
  client?: Client,
  opts: CreateSessionOptions = {}
): Promise<AgentSession> {
  const customTools = createScheduleTools({
    schedulesDir: deps.schedulesDir,
    defaultDestination: ctx.defaultDestination,
    defaultUserId: ctx.defaultUserId,
    onChange: deps.onSchedulesChanged,
    client,
  });
  const { session } = await createAgentSession({
    cwd: deps.cwd,
    model: deps.model,
    authStorage: deps.authStorage,
    modelRegistry: deps.modelRegistry,
    resourceLoader: deps.resourceLoader,
    settingsManager: deps.settingsManager,
    sessionManager: opts.sessionManager ?? SessionManager.inMemory(),
    customTools,
  });
  return session;
}

export function describeModel(): string {
  return `${PROVIDER}/${MODEL_ID}`;
}