import type { Config } from '../config/index.js';
import type { Lifecycle } from './lifecycle.js';
import type { ToolRegistry, ToolExecutor } from '../tools/index.js';
import type { AgentOrchestrator } from '../backends/index.js';
import type { OutboundAttachmentCollector } from '../backends/native/attachments.js';
import { ModelRouter } from '../models/index.js';
import { SessionManager } from '../session/index.js';
import { GatewayServer } from '../gateway/index.js';
import { ChannelRegistry, PairingManager, type PairingStore } from '../channels/index.js';
import { HeartbeatMonitor } from '../automation/index.js';
import { McpManager } from '../mcp/index.js';
import { SkillRegistry, SkillInstaller, loadAllSkills } from '../skills/index.js';
import { assembleSystemPrompt } from '../prompt/index.js';
import { resolve } from 'path';
import { homedir } from 'os';
import type { MemoryStore } from '../memory/store.js';

// ── Skills ──────────────────────────────────────────────────────

export interface SkillsResult {
  skillRegistry: SkillRegistry;
  skillInstaller: SkillInstaller;
}

export function initSkills(config: Config): SkillsResult {
  const defaultManagedDir = resolve(homedir(), '.flynn/workspace/skills');
  const skillRegistry = new SkillRegistry();
  const skillInstaller = new SkillInstaller(config.skills.managed_dir ?? defaultManagedDir);

  const skills = loadAllSkills({
    bundledDir: config.skills.bundled_dir,
    managedDir: config.skills.managed_dir ?? defaultManagedDir,
    workspaceDir: config.skills.workspace_dir,
  });

  for (const skill of skills) {
    skillRegistry.register(skill);
  }

  if (skills.length > 0) {
    const available = skillRegistry.listAvailable().length;
    console.log(`Loaded ${skills.length} skill(s) (${available} available)`);
  }

  return { skillRegistry, skillInstaller };
}

// ── MCP ─────────────────────────────────────────────────────────

export async function initMcp(config: Config, lifecycle: Lifecycle, toolRegistry: ToolRegistry): Promise<McpManager> {
  const mcpManager = new McpManager(toolRegistry);

  if (config.mcp.servers.length > 0) {
    console.log(`Starting ${config.mcp.servers.length} MCP server(s)...`);
    await mcpManager.startAll(config.mcp.servers);
  }

  lifecycle.onShutdown(async () => {
    await mcpManager.stopAll();
    console.log('MCP servers stopped');
  });

  return mcpManager;
}

// ── System Prompt ───────────────────────────────────────────────

export function loadSystemPrompt(config: Config, skillRegistry: SkillRegistry): string {
  const searchDirs = [
    process.cwd(),
    resolve(import.meta.dirname, '../..'),
    ...(config.prompt.search_dirs ?? []),
  ];

  const result = assembleSystemPrompt({
    searchDirs,
    extraSections: config.prompt.extra_sections,
  });

  if (result.loadedFiles.length > 0) {
    console.log(`Loaded prompt templates: ${result.loadedFiles.map(f => f.split('/').pop()).join(', ')}`);
  }

  let prompt = result.prompt;
  const skillAdditions = skillRegistry.getSystemPromptAdditions();
  if (skillAdditions) {
    prompt = `${prompt}\n\n# Available Skills\n\n${skillAdditions}`;
  }

  return prompt;
}

// ── Pairing Manager ─────────────────────────────────────────────

export function initPairingManager(config: Config, store?: PairingStore): PairingManager | undefined {
  if (!config.pairing.enabled) {return undefined;}

  const ttlMatch = config.pairing.code_ttl.match(/^(\d+)(s|m|h)$/);
  const codeTtlMs = ttlMatch
    ? Number(ttlMatch[1]) * ({ s: 1000, m: 60_000, h: 3_600_000 }[ttlMatch[2] as 's' | 'm' | 'h'])
    : 5 * 60_000;

  const manager = new PairingManager({
    enabled: true,
    codeTtl: codeTtlMs,
    codeLength: config.pairing.code_length,
  }, store);
  console.log(`Pairing codes enabled (TTL: ${config.pairing.code_ttl}, length: ${config.pairing.code_length})`);
  return manager;
}

// ── Gateway ─────────────────────────────────────────────────────

export interface GatewayDeps {
  config: Config;
  sessionManager: SessionManager;
  modelRouter: ModelRouter;
  systemPrompt: string;
  toolRegistry: ToolRegistry;
  toolExecutor: ToolExecutor;
  channelRegistry: ChannelRegistry;
  pairingManager?: PairingManager;
  lifecycle: Lifecycle;
  getChannelAgents: () => Map<string, { orchestrator: AgentOrchestrator; collector: OutboundAttachmentCollector }> | null;
  memoryStore?: MemoryStore;
}

export function createGateway(deps: GatewayDeps): GatewayServer {
  const { config, sessionManager, modelRouter, systemPrompt, toolRegistry, toolExecutor, channelRegistry, pairingManager, lifecycle, getChannelAgents } = deps;

  const gateway = new GatewayServer({
    port: config.server.port,
    host: config.server.localhost ? '127.0.0.1' : '0.0.0.0',
    sessionManager,
    modelClient: modelRouter,
    systemPrompt,
    toolRegistry,
    toolExecutor,
    auth: {
      token: config.server.token,
      tailscaleIdentity: config.server.tailscale_identity,
    },
    authHttp: config.server.auth_http,
    lock: config.server.lock,
    uiDir: resolve(import.meta.dirname, '../gateway/ui'),
    config,
    channelRegistry,
    pairingManager,
    memoryStore: deps.memoryStore,
    restart: async () => {
      console.log('Restart requested via gateway');
      await lifecycle.shutdown();
      process.exit(75);
    },
    getTokenUsage: () => {
      const results: Array<{
        sessionId: string;
        primary: { inputTokens: number; outputTokens: number; calls: number };
        delegation: Record<string, { inputTokens: number; outputTokens: number; calls: number }>;
        total: { inputTokens: number; outputTokens: number; calls: number; estimatedCost: number };
      }> = [];

      const sessionBridge = gateway.getSessionBridge();
      for (const entry of sessionBridge.getAllUsage()) {
        results.push(entry);
      }

      const channelAgents = getChannelAgents();
      if (channelAgents) {
        for (const [sessionId, { orchestrator }] of channelAgents) {
          const usage = orchestrator.getUsage();
          results.push({
            sessionId,
            primary: usage.primary,
            delegation: usage.delegation,
            total: usage.total,
          });
        }
      }

      return results;
    },
  });

  if (config.server.token) {
    console.log(`Gateway auth: token required${config.server.tailscale_identity ? ' + Tailscale identity' : ''}`);
  }

  return gateway;
}

// ── Service Startup ─────────────────────────────────────────────

export async function startServices(deps: {
  config: Config;
  lifecycle: Lifecycle;
  channelRegistry: ChannelRegistry;
  gateway: GatewayServer;
  modelRouter: ModelRouter;
  memoryDir: string;
  dataDir: string;
}): Promise<void> {
  const { config, lifecycle, channelRegistry, gateway, modelRouter, memoryDir, dataDir } = deps;

  // Register shutdown handler for channels
  lifecycle.onShutdown(async () => {
    await channelRegistry.stopAll();
    console.log('Channel adapters stopped');
  });

  // Start all channel adapters
  await channelRegistry.startAll();

  // Start gateway (HTTP + WS server)
  lifecycle.onShutdown(async () => {
    await gateway.stop();
    console.log('Gateway server stopped');
  });

  await gateway.start();

  // Tailscale Serve
  if (config.server.tailscale?.serve) {
    const { startTailscaleServe, stopTailscaleServe } = await import('../gateway/tailscale.js');
    const tsConfig = {
      localPort: config.server.port,
      servePort: config.server.tailscale.port,
      hostname: config.server.tailscale.hostname,
    };
    try {
      await startTailscaleServe(tsConfig);
      lifecycle.onShutdown(async () => {
        await stopTailscaleServe(tsConfig);
      });
    } catch {
      console.warn('Tailscale Serve failed to start — gateway still accessible on local port');
    }
  }

  // Heartbeat Monitor
  const heartbeatMonitor = new HeartbeatMonitor({
    config: config.automation.heartbeat,
    getGatewayPort: () => config.server.port,
    modelRouter,
    channelLister: channelRegistry,
    memoryDir: config.memory.enabled ? memoryDir : undefined,
    dataDir,
    channelLookup: channelRegistry,
  });

  heartbeatMonitor.start();

  lifecycle.onShutdown(async () => {
    heartbeatMonitor.stop();
    console.log('Heartbeat monitor stopped');
  });

  // Signal handlers
  const signalHandler = () => {
    lifecycle.shutdown().then(() => process.exit(0));
  };

  process.on('SIGINT', signalHandler);
  process.on('SIGTERM', signalHandler);

  lifecycle.onShutdown(async () => {
    process.off('SIGINT', signalHandler);
    process.off('SIGTERM', signalHandler);
  });

  console.log('Flynn daemon started');
}