import fs from "node:fs";
import path from "node:path";
import { promisify } from "node:util";
import { execFile } from "node:child_process";

import {
  DIRECT_SSH_KEY_PATH,
  DIRECT_SSH_TIMEOUT_MS,
  FLEET_CONFIG,
  REPO_ACCESS_ROOTS,
  SWARM_HOST_WORKTREES_DIR,
  SWARM_REPO_MAP_FILE,
  SWARM_TASKS_FILE,
  SWARM_WORKTREES_DIR,
  ZEROCLAW_WEBHOOK_TIMEOUT_MS,
} from "@/lib/fleet-config";
import { findAgentByAssignmentKey } from "@/lib/agents";
import { appendTaskEvent, applyTaskCallback, findTask, updateTask } from "@/lib/tasks";
import type { DispatchState, TaskCallbackPayload } from "@/lib/types";

const execFileAsync = promisify(execFile);

type DispatchResult = {
  state: DispatchState;
  summary: string;
  detail: string;
  callback?: TaskCallbackPayload;
};

function defaultModelForAgent(agent: string) {
  switch (agent) {
    case "opencode":
      return "zai-coding-plan/glm-4.7";
    case "gemini":
      return "gemini-3.1-pro";
    default:
      return "gpt-5.3-codex";
  }
}

function readRepoMap() {
  if (!fs.existsSync(SWARM_REPO_MAP_FILE)) {
    throw new Error(`missing_repo_map:${SWARM_REPO_MAP_FILE}`);
  }

  return JSON.parse(fs.readFileSync(SWARM_REPO_MAP_FILE, "utf8")) as Record<string, string>;
}

function ensureAllowedRepoPath(repoPath: string) {
  const resolved = path.resolve(repoPath);
  const allowed = REPO_ACCESS_ROOTS.some((root) => resolved.startsWith(path.resolve(root)));
  if (!allowed) {
    throw new Error(`repo_path_not_allowed:${resolved}`);
  }
  return resolved;
}

function ensureSwarmRegistry() {
  fs.mkdirSync(path.dirname(SWARM_TASKS_FILE), { recursive: true });
  if (!fs.existsSync(SWARM_TASKS_FILE)) {
    fs.writeFileSync(SWARM_TASKS_FILE, JSON.stringify({ tasks: [] }, null, 2));
  }
}

function extractTagValue(tags: string[], prefix: string) {
  const match = tags.find((tag) => tag.startsWith(prefix));
  return match ? match.slice(prefix.length) : null;
}

function truncateOutput(output: string, maxLength = 4000) {
  const trimmed = output.trim();
  if (trimmed.length <= maxLength) {
    return trimmed;
  }
  return `${trimmed.slice(0, maxLength - 15)}\n...[truncated]`;
}

async function dispatchOpenClawTask(taskId: number): Promise<DispatchResult> {
  const task = await findTask(taskId);
  if (!task) {
    throw new Error("task_not_found");
  }
  if (!task.repo_slug) {
    throw new Error("repo_slug_required_for_openclaw_dispatch");
  }

  const repoMap = readRepoMap();
  const repoPath = ensureAllowedRepoPath(repoMap[task.repo_slug] || "");
  if (!repoPath || !fs.existsSync(path.join(repoPath, ".git"))) {
    throw new Error(`repo_not_available:${task.repo_slug}`);
  }

  await execFileAsync("git", ["config", "--global", "--add", "safe.directory", repoPath]);

  const agentName = task.preferred_agent || "codex";
  const taskKey = `taskboard-${task.id}`;
  const repoName = path.basename(repoPath);
  const worktree = path.join(SWARM_WORKTREES_DIR, repoName, taskKey);
  const hostWorktree = path.join(SWARM_HOST_WORKTREES_DIR, repoName, taskKey);
  const branch = `feat/taskboard-${task.id}`;
  const baseBranch = task.base_branch || "main";

  fs.mkdirSync(path.dirname(worktree), { recursive: true });
  if (!fs.existsSync(worktree)) {
    try {
      await execFileAsync("git", ["-C", repoPath, "fetch", "origin", baseBranch]);
    } catch {
      // Keep going. Many local repos already have the base branch available.
    }
    await execFileAsync("git", ["-C", repoPath, "worktree", "add", worktree, "-b", branch, `origin/${baseBranch}`]);
  }

  ensureSwarmRegistry();
  const registry = JSON.parse(fs.readFileSync(SWARM_TASKS_FILE, "utf8")) as { tasks?: Array<Record<string, unknown>> };
  const tasks = Array.isArray(registry.tasks) ? registry.tasks : [];
  const existing = tasks.find((entry) => entry.taskboardTaskId === task.id);
  if (!existing) {
    tasks.push({
      id: taskKey,
      agent: agentName,
      repo: repoName,
      repoPath,
      repoSlug: task.repo_slug,
      worktree: hostWorktree,
      branch,
      baseBranch,
      tmuxSession: `${agentName}-${taskKey}`,
      description: task.description,
      prompt: `Taskboard task #${task.id}: ${task.title}\n\n${task.description}`,
      status: "queued",
      notifyOnComplete: true,
      attempts: 0,
      maxAttempts: 3,
      model: task.model_hint || defaultModelForAgent(agentName),
      reasoning: task.reasoning_effort || "high",
      taskboardTaskId: task.id,
      startedAt: null,
      completedAt: null,
      createdAt: Date.now(),
      checks: {
        prCreated: false,
        ciPassed: false,
        reviewPassed: false,
      },
    });
  } else {
    existing.repoPath = repoPath;
    existing.repoSlug = task.repo_slug;
    existing.worktree = hostWorktree;
    existing.branch = branch;
    existing.baseBranch = baseBranch;
    existing.agent = agentName;
    existing.tmuxSession = `${agentName}-${taskKey}`;
  }

  fs.writeFileSync(SWARM_TASKS_FILE, JSON.stringify({ tasks }, null, 2));

  return {
    state: "dispatched" as const,
    summary: `Queued in OpenClaw swarm for ${agentName}`,
    detail: `${task.repo_slug} -> ${hostWorktree}`,
  };
}

async function dispatchZeroClawTask(taskId: number): Promise<DispatchResult> {
  const task = await findTask(taskId);
  if (!task) {
    throw new Error("task_not_found");
  }
  const agent = await findAgentByAssignmentKey(task.assignee);
  if (!agent) {
    throw new Error("assignee_not_found");
  }

  const urlEnv = agent.slug === "grizzley-zeroclaw" ? "ZEROCLAW_GRIZZLEY_URL" : "ZEROCLAW_ICE_URL";
  const tokenEnv = agent.slug === "grizzley-zeroclaw" ? "ZEROCLAW_GRIZZLEY_TOKEN" : "ZEROCLAW_ICE_TOKEN";
  const baseUrl = process.env[urlEnv];
  if (!baseUrl) {
    throw new Error(`missing_gateway_url:${urlEnv}`);
  }

  const controller = new AbortController();
  const timeout = setTimeout(() => controller.abort(), ZEROCLAW_WEBHOOK_TIMEOUT_MS);
  const response = await fetch(`${baseUrl.replace(/\/$/, "")}/webhook`, {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      ...(process.env[tokenEnv] ? { Authorization: `Bearer ${process.env[tokenEnv]}` } : {}),
    },
    body: JSON.stringify({
      message: `Taskboard task #${task.id}: ${task.title}\nHost: ${task.target_host || agent.host}\nChannel: ${task.target_channel || "n/a"}\n\n${task.description}`,
    }),
    signal: controller.signal,
  });
  clearTimeout(timeout);

  if (!response.ok) {
    const responseText = await response.text();
    throw new Error(`webhook_failed:${response.status}:${responseText}`);
  }

  const responseText = await response.text();
  return {
    state: "dispatched" as const,
    summary: `Posted to ${agent.name} webhook`,
    detail: responseText || `${agent.host} webhook accepted`,
  };
}

function findDirectAgentDefinition(assignmentKey: string) {
  return (
    FLEET_CONFIG.directAgents.find(
      (agent) => agent.assignmentKey === assignmentKey || agent.aliases.includes(assignmentKey),
    ) || null
  );
}

async function dispatchDirectTask(taskId: number): Promise<DispatchResult> {
  const task = await findTask(taskId);
  if (!task) {
    throw new Error("task_not_found");
  }

  const directAgent = findDirectAgentDefinition(task.assignee);
  if (!directAgent) {
    throw new Error("direct_target_not_found");
  }

  const actionKey = extractTagValue(task.tags, "action:") || directAgent.dispatch.defaultAction;
  const action = directAgent.dispatch.actions.find((entry) => entry.key === actionKey);
  if (!action) {
    throw new Error(`unsupported_direct_action:${actionKey}`);
  }

  const sshArgs = [
    "-F",
    "/dev/null",
    "-o",
    "BatchMode=yes",
    "-o",
    "StrictHostKeyChecking=accept-new",
    "-o",
    "ConnectTimeout=15",
    "-o",
    "IdentitiesOnly=yes",
    "-o",
    "UserKnownHostsFile=/tmp/taskboard_known_hosts",
    "-i",
    DIRECT_SSH_KEY_PATH,
    "-p",
    String(directAgent.dispatch.port),
    `${directAgent.dispatch.user}@${directAgent.dispatch.hostname}`,
    action.command,
  ];

  try {
    const { stdout, stderr } = await execFileAsync("ssh", sshArgs, {
      timeout: DIRECT_SSH_TIMEOUT_MS,
      maxBuffer: 1024 * 1024,
    });
    const detail = truncateOutput([stdout, stderr].filter(Boolean).join("\n"));
    return {
      state: "completed" as const,
      summary: `${action.successSummary}`,
      detail,
      callback: {
        status: "Done",
        dispatch_state: "completed",
        summary: action.successSummary,
        detail,
        completed_by: `direct-ssh:${directAgent.host}`,
        last_error: null,
        last_dispatch_at: new Date().toISOString(),
      },
    };
  } catch (error) {
    const execError = error as Error & { stdout?: string; stderr?: string };
    const detail = truncateOutput([execError.stdout, execError.stderr, execError.message].filter(Boolean).join("\n"));
    throw new Error(`direct_ssh_failed:${directAgent.host}:${action.key}:${detail}`);
  }
}

export async function dispatchTask(taskId: number) {
  const task = await findTask(taskId);
  if (!task) {
    throw new Error("task_not_found");
  }
  if (!task.assignee) {
    throw new Error("assignee_required");
  }

  const agent = await findAgentByAssignmentKey(task.assignee);
  if (!agent) {
    throw new Error("assignee_not_found");
  }

  await appendTaskEvent({
    taskId,
    assignee: task.assignee,
    family: task.family,
    host: task.target_host,
    eventType: "dispatch_requested",
    state: task.dispatch_state,
    summary: `Dispatch requested for ${agent.name}`,
    detail: task.description,
  });

  try {
    const result =
      agent.family === "openclaw"
        ? await dispatchOpenClawTask(taskId)
        : agent.family === "zeroclaw"
          ? await dispatchZeroClawTask(taskId)
          : await dispatchDirectTask(taskId);

    if (result.callback) {
      const updated = await applyTaskCallback(taskId, result.callback);
      if (!updated) {
        throw new Error("task_not_found_after_callback");
      }

      return updated;
    }

    const updated = await updateTask(taskId, {
      status: task.status === "Backlog" ? "Todo" : task.status,
      dispatch_state: result.state,
      last_dispatch_at: new Date().toISOString(),
      last_error: null,
    });

    if (!updated) {
      throw new Error("task_not_found_after_dispatch");
    }

    await appendTaskEvent({
      taskId,
      assignee: updated.assignee,
      family: updated.family,
      host: updated.target_host,
      eventType: "dispatch_succeeded",
      state: updated.dispatch_state,
      summary: result.summary,
      detail: result.detail,
    });

    return updated;
  } catch (error) {
    const message = error instanceof Error ? error.message : String(error);
    const updated = await updateTask(taskId, {
      dispatch_state: "failed",
      last_error: message,
    });
    await appendTaskEvent({
      taskId,
      assignee: task.assignee,
      family: task.family,
      host: task.target_host,
      eventType: "dispatch_failed",
      state: "failed",
      summary: "Dispatch failed",
      detail: message,
    });
    if (!updated) {
      throw error;
    }
    return updated;
  }
}