import { Command } from 'commander';
import { init } from './commands/init.js';
import { status } from './commands/status.js';
import { memoryAdd, memorySearch, memoryList } from './commands/memory.js';
import { taskCreate, taskList, taskShow, taskClaim, taskDone } from './commands/task.js';
import { handoffCreate, handoffRead, handoffList } from './commands/handoff.js';
import { decisionCreate, decisionList } from './commands/decision.js';
import { delegate } from './commands/delegate.js';
import { serverStart } from './commands/server.js';
import { update } from './commands/update.js';
import { watchEvents } from './commands/watch.js';
import { loadConfig } from '../core/config.js';
import { findProjectRoot } from '../core/paths.js';
import { discoverServer } from '../discovery.js';
import { remoteClient, RemoteError } from './remoteClient.js';

interface ResolvedContext {
  serverUrl?: string;
  projectCwd: string;
}

/**
 * Decide, for a single command invocation, whether to talk to a remote server
 * or operate on local files, and which directory holds the project.
 *
 * Precedence:
 *   1. --server flag / AGENTHUB_SERVER env var (explicit wins)
 *   2. Nearest `.agenthub` project found by walking up from cwd (cwd-robust):
 *      use its configured serverUrl if set, otherwise local mode at that root.
 *   3. No project anywhere → try zero-config LAN auto-discovery; if a server is
 *      found, use it; otherwise fall back to local mode (which then errors
 *      gracefully instead of crashing with a raw stack trace).
 */
async function resolveContext(program: Command, cwd: string): Promise<ResolvedContext> {
  const flag = (program.opts().server as string | undefined) || process.env.AGENTHUB_SERVER;
  if (flag) return { serverUrl: flag, projectCwd: cwd };

  const root = findProjectRoot(cwd);
  if (root) {
    try {
      const config = loadConfig(root);
      return { serverUrl: config.serverUrl, projectCwd: root };
    } catch {
      return { projectCwd: root };
    }
  }

  const discovered = await discoverServer(2000);
  if (discovered) {
    console.error(`No local AgentHub project found — using discovered server at ${discovered}.`);
    return { serverUrl: discovered, projectCwd: cwd };
  }
  return { projectCwd: cwd };
}

async function runRemote(serverUrl: string, fn: () => Promise<void>): Promise<void> {
  try {
    await fn();
  } catch (err) {
    if (err instanceof RemoteError) {
      if (err.status === 0) {
        console.error(`AgentHub server at ${serverUrl} is not reachable. Is 'agenthub server start --host 0.0.0.0' running?`);
      } else {
        console.error(`AgentHub server error (${err.status}): ${err.message}`);
      }
      process.exit(1);
    }
    throw err;
  }
}

export function createProgram(cwd: string): Command {
  const program = new Command('agenthub')
    .description('Local coordination layer for AI coding agents')
    .version('0.1.0')
    .option('--server <url>', 'AgentHub server URL (env: AGENTHUB_SERVER)');

  program
    .command('init')
    .description('Initialize AgentHub in the current directory')
    .option('-n, --project-name <name>', 'Project name')
    .option('-y, --yes', 'Use defaults without prompts')
    .option('--server <url>', 'Connect to a remote AgentHub server; use "auto" to discover one on the LAN')
    .action((options) => {
      init(cwd, { ...options, server: options.server || (program.opts().server as string | undefined) });
    });

  program
    .command('status')
    .description('Show project status')
    .option('-u, --update', 'Regenerate status before showing')
    .action(async (options) => {
      const { serverUrl, projectCwd } = await resolveContext(program, cwd);
      if (serverUrl) {
        await runRemote(serverUrl, async () => {
          const body = options.update ? await remoteClient.updateStatus(serverUrl) : await remoteClient.getStatus(serverUrl);
          console.log(body);
        });
      } else {
        status(projectCwd, options);
      }
    });

  const memoryCmd = new Command('memory').description('Manage memory entries');
  memoryCmd
    .command('add')
    .description('Add a memory entry')
    .option('--title <title>', 'Title')
    .option('--category <category>', 'Category')
    .option('--content <content>', 'Content')
    .option(
      '--task <ids>',
      'Link to task IDs (comma-separated, e.g. TSK-0001 or TSK-0001,TSK-0002)',
    )
    .option('--tokens <n>', 'Tokens consumed (optional, for activity timeline)')
    .option('--duration <ms>', 'Duration in milliseconds (optional, for activity timeline)')
    .option('--by <agent>', 'Agent that produced this result (optional)')
    .action(async (options) => {
      const { serverUrl, projectCwd } = await resolveContext(program, cwd);

      // Parse CLI string values into the types the service expects.
      const relatedTasks: string[] = options.task
        ? (Array.isArray(options.task)
            ? options.task
            : options.task
                .split(',')
                .map((s: string) => s.trim())
                .filter(Boolean))
        : [];
      const tokens = options.tokens != null ? Number(options.tokens) : undefined;
      const duration = options.duration != null ? Number(options.duration) : undefined;

      if (serverUrl) {
        await runRemote(serverUrl, async () => {
          const memory = await remoteClient.addMemory(serverUrl, {
            title: options.title as string | undefined,
            category: options.category as string | undefined,
            content: options.content as string | undefined,
            relatedTasks,
            tokens,
            duration,
            by: options.by as string | undefined,
          } as Partial<import('../core/schema.js').Memory>);
          console.log(`Memory saved as ${memory.id}.`);
        });
      } else {
        await memoryAdd(projectCwd, {
          title: options.title as string | undefined,
          content: options.content as string | undefined,
          relatedTasks,
          tokens,
          duration,
          by: options.by as string | undefined,
        });
      }
    });
  memoryCmd
    .command('search <query>')
    .description('Search memory and tasks')
    .action(async (query) => {
      const { serverUrl, projectCwd } = await resolveContext(program, cwd);
      if (serverUrl) {
        await runRemote(serverUrl, async () => {
          const results = await remoteClient.searchMemory(serverUrl, query);
          if (results.length === 0) { console.log('No results found.'); return; }
          for (const r of results) console.log(`[${r.type}] ${r.id}: ${r.title}`);
        });
      } else {
        memorySearch(projectCwd, query);
      }
    });
  memoryCmd
    .command('list')
    .description('List memory entries')
    .action(async () => {
      const { serverUrl, projectCwd } = await resolveContext(program, cwd);
      if (serverUrl) {
        await runRemote(serverUrl, async () => {
          const memories = await remoteClient.listMemory(serverUrl);
          if (memories.length === 0) { console.log('No memory entries found.'); return; }
          for (const m of memories) console.log(`${m.id}: ${m.title}`);
        });
      } else {
        memoryList(projectCwd);
      }
    });
  program.addCommand(memoryCmd);

  const taskCmd = new Command('task').description('Manage tasks');
  taskCmd
    .command('create')
    .description('Create a task')
    .option('--title <title>', 'Title')
    .option('--role <role>', 'Role')
    .option('--priority <priority>', 'Priority')
    .action(async (options) => {
      const { serverUrl, projectCwd } = await resolveContext(program, cwd);
      if (serverUrl) {
        await runRemote(serverUrl, async () => {
          const task = await remoteClient.createTask(serverUrl, options);
          console.log(`Created ${task.id}: ${task.title}`);
        });
      } else {
        await taskCreate(projectCwd, options);
      }
    });
  taskCmd
    .command('list')
    .description('List tasks')
    .option('--status <status>', 'Filter by status')
    .option('--role <role>', 'Filter by role')
    .action(async (options) => {
      const { serverUrl, projectCwd } = await resolveContext(program, cwd);
      if (serverUrl) {
        await runRemote(serverUrl, async () => {
          const tasks = await remoteClient.listTasks(serverUrl, options);
          if (tasks.length === 0) { console.log('No tasks found.'); return; }
          for (const t of tasks) console.log(`${t.id} [${t.status}] (${t.role ?? 'unassigned'}) ${t.title}`);
        });
      } else {
        taskList(projectCwd, options);
      }
    });
  taskCmd
    .command('show <id>')
    .description('Show a task')
    .action(async (id) => {
      const { serverUrl, projectCwd } = await resolveContext(program, cwd);
      if (serverUrl) {
        await runRemote(serverUrl, async () => {
          const { task, body } = await remoteClient.getTask(serverUrl, id);
          console.log(`# ${task.title}`);
          console.log(`Status: ${task.status} | Role: ${task.role ?? '-'} | Priority: ${task.priority}`);
          console.log('\n' + body);
        });
      } else {
        taskShow(projectCwd, id);
      }
    });
  taskCmd
    .command('claim <id>')
    .description('Claim a task')
    .requiredOption('--agent <agent>', 'Agent name')
    .action(async (id, options) => {
      const { serverUrl, projectCwd } = await resolveContext(program, cwd);
      if (serverUrl) {
        await runRemote(serverUrl, async () => {
          await remoteClient.claimTask(serverUrl, id, options.agent);
          console.log(`${id} claimed by ${options.agent}.`);
        });
      } else {
        taskClaim(projectCwd, id, options.agent);
      }
    });
  taskCmd
    .command('done <id>')
    .description('Mark a task as done')
    .option('--tokens <n>', 'Tokens consumed (optional, for activity timeline)')
    .option('--duration <ms>', 'Duration in milliseconds (optional, for activity timeline)')
    .option('--by <agent>', 'Agent that completed the task (optional)')
    .action(async (id, options) => {
      const meta = {
        tokens: options.tokens != null ? Number(options.tokens) : undefined,
        duration: options.duration != null ? Number(options.duration) : undefined,
        by: options.by as string | undefined,
      };
      const { serverUrl, projectCwd } = await resolveContext(program, cwd);
      if (serverUrl) {
        await runRemote(serverUrl, async () => {
          await remoteClient.doneTask(serverUrl, id, meta);
          console.log(`${id} marked as done.`);
        });
      } else {
        taskDone(projectCwd, id, meta);
      }
    });
  program.addCommand(taskCmd);

  const handoffCmd = new Command('handoff').description('Manage handoffs');
  handoffCmd
    .command('create')
    .description('Create a handoff')
    .option('--fromRole <role>', 'From role')
    .option('--toRole <role>', 'To role')
    .option('--taskId <id>', 'Related task id')
    .option('--summary <summary>', 'Summary')
    .option('--context <context>', 'Context')
    .action(async (options) => {
      const { serverUrl, projectCwd } = await resolveContext(program, cwd);
      if (serverUrl) {
        await runRemote(serverUrl, async () => {
          const handoff = await remoteClient.createHandoff(serverUrl, options);
          console.log(`Handoff created: ${handoff.id}`);
        });
      } else {
        await handoffCreate(projectCwd, options);
      }
    });
  handoffCmd
    .command('read <id>')
    .description('Read a handoff')
    .action(async (id) => {
      const { serverUrl, projectCwd } = await resolveContext(program, cwd);
      if (serverUrl) {
        await runRemote(serverUrl, async () => {
          const { handoff, body } = await remoteClient.getHandoff(serverUrl, id);
          console.log(`# ${handoff.summary}`);
          console.log(`From: ${handoff.fromRole} → ${handoff.toRole}`);
          if (handoff.taskId) console.log(`Task: ${handoff.taskId}`);
          console.log('\n' + body);
        });
      } else {
        handoffRead(projectCwd, id);
      }
    });
  handoffCmd
    .command('list')
    .description('List handoffs')
    .action(async () => {
      const { serverUrl, projectCwd } = await resolveContext(program, cwd);
      if (serverUrl) {
        await runRemote(serverUrl, async () => {
          const handoffs = await remoteClient.listHandoffs(serverUrl);
          if (handoffs.length === 0) { console.log('No handoffs found.'); return; }
          for (const h of handoffs) console.log(`${h.id}: ${h.title}`);
        });
      } else {
        handoffList(projectCwd);
      }
    });
  program.addCommand(handoffCmd);

  const decisionCmd = new Command('decision').description('Manage decisions');
  decisionCmd
    .command('create')
    .description('Create a decision record')
    .option('--title <title>', 'Title')
    .option('--context <context>', 'Context')
    .option('--decision <decision>', 'Decision')
    .action(async (options) => {
      const { serverUrl, projectCwd } = await resolveContext(program, cwd);
      if (serverUrl) {
        await runRemote(serverUrl, async () => {
          const decision = await remoteClient.createDecision(serverUrl, options);
          console.log(`Decision recorded: ${decision.id}`);
        });
      } else {
        await decisionCreate(projectCwd, options);
      }
    });
  decisionCmd
    .command('list')
    .description('List decisions')
    .action(async () => {
      const { serverUrl, projectCwd } = await resolveContext(program, cwd);
      if (serverUrl) {
        await runRemote(serverUrl, async () => {
          const decisions = await remoteClient.listDecisions(serverUrl);
          if (decisions.length === 0) { console.log('No decisions found.'); return; }
          for (const d of decisions) console.log(`${d.id}: ${d.title}`);
        });
      } else {
        decisionList(projectCwd);
      }
    });
  program.addCommand(decisionCmd);

  program
    .command('delegate')
    .description('Suggest or auto-delegate open tasks')
    .option('--auto', 'Create handoff automatically')
    .action(async (options) => {
      const { serverUrl, projectCwd } = await resolveContext(program, cwd);
      if (serverUrl) {
        await runRemote(serverUrl, async () => {
          const result = await remoteClient.delegate(serverUrl, options.auto ?? false);
          if (!result.suggestion) { console.log('No open tasks to delegate.'); return; }
          const s = result.suggestion;
          console.log('Suggested delegation:');
          console.log(`  Task: ${s.task.id} — ${s.task.title}`);
          console.log(`  Role: ${s.role}`);
          console.log(`  Preferred agent: ${s.preferredAgent}`);
          if (result.handoff) console.log('Handoff created automatically.');
          else console.log('Run with --auto to create the handoff.');
        });
      } else {
        await delegate(projectCwd, options);
      }
    });

  program
    .command('update')
    .description('Update AgentHub to the latest version')
    .action(async () => {
      await update();
    });

  // ─── watch ───────────────────────────────────────────────────────────────
  program
    .command('watch')
    .description('Stream live AgentHub events from a running server (SSE)')
    .option('--once', 'Exit 0 after the first event (useful as a blocking wait for agents)')
    .option('--role <role>', 'Client-side role filter (only show events for this role)')
    .action(async (options) => {
      const { serverUrl } = await resolveContext(program, cwd);
      if (!serverUrl) {
        console.error('No AgentHub server found. Start one with: agenthub server start --host 0.0.0.0');
        process.exit(1);
        return;
      }
      await watchEvents(serverUrl, { once: options.once as boolean | undefined, role: options.role as string | undefined });
    });

  // ─── server ──────────────────────────────────────────────────────────────
  const serverCmd = new Command('server').description('Optional local API server');
  serverCmd
    .command('start')
    .description('Start the optional AgentHub API server')
    .option('-p, --port <port>', 'Port', '3377')
    .option('-h, --host <host>', 'Host to bind to', '127.0.0.1')
    .action((options) => {
      // Serve the project root if we are inside one, so `server start` works
      // from any subdirectory and always serves the single source of truth.
      const projectCwd = findProjectRoot(cwd) ?? cwd;
      serverStart(projectCwd, { port: parseInt(options.port, 10), host: options.host });
    });
  program.addCommand(serverCmd);

  return program;
}