import fs from "node:fs/promises";
import os from "node:os";
import path from "node:path";
import { fileURLToPath } from "node:url";

import { isSubagentSessionKey } from "../routing/session-key.js";
import { runCommandWithTimeout } from "../process/exec.js";
import { resolveUserPath } from "../utils.js";

export function resolveDefaultAgentWorkspaceDir(
  env: NodeJS.ProcessEnv = process.env,
  homedir: () => string = os.homedir,
): string {
  const profile = env.CLAWDBOT_PROFILE?.trim();
  if (profile && profile.toLowerCase() !== "default") {
    return path.join(homedir(), `clawd-${profile}`);
  }
  return path.join(homedir(), "clawd");
}

export const DEFAULT_AGENT_WORKSPACE_DIR = resolveDefaultAgentWorkspaceDir();
export const DEFAULT_AGENTS_FILENAME = "AGENTS.md";
export const DEFAULT_SOUL_FILENAME = "SOUL.md";
export const DEFAULT_TOOLS_FILENAME = "TOOLS.md";
export const DEFAULT_IDENTITY_FILENAME = "IDENTITY.md";
export const DEFAULT_USER_FILENAME = "USER.md";
export const DEFAULT_HEARTBEAT_FILENAME = "HEARTBEAT.md";
export const DEFAULT_BOOTSTRAP_FILENAME = "BOOTSTRAP.md";

const TEMPLATE_DIR = path.resolve(
  path.dirname(fileURLToPath(import.meta.url)),
  "../../docs/reference/templates",
);

function stripFrontMatter(content: string): string {
  if (!content.startsWith("---")) return content;
  const endIndex = content.indexOf("\n---", 3);
  if (endIndex === -1) return content;
  const start = endIndex + "\n---".length;
  let trimmed = content.slice(start);
  trimmed = trimmed.replace(/^\s+/, "");
  return trimmed;
}

async function loadTemplate(name: string): Promise<string> {
  const templatePath = path.join(TEMPLATE_DIR, name);
  try {
    const content = await fs.readFile(templatePath, "utf-8");
    return stripFrontMatter(content);
  } catch {
    throw new Error(
      `Missing workspace template: ${name} (${templatePath}). Ensure docs/reference/templates are packaged.`,
    );
  }
}

export type WorkspaceBootstrapFileName =
  | typeof DEFAULT_AGENTS_FILENAME
  | typeof DEFAULT_SOUL_FILENAME
  | typeof DEFAULT_TOOLS_FILENAME
  | typeof DEFAULT_IDENTITY_FILENAME
  | typeof DEFAULT_USER_FILENAME
  | typeof DEFAULT_HEARTBEAT_FILENAME
  | typeof DEFAULT_BOOTSTRAP_FILENAME;

export type WorkspaceBootstrapFile = {
  name: WorkspaceBootstrapFileName;
  path: string;
  content?: string;
  missing: boolean;
};

async function writeFileIfMissing(filePath: string, content: string) {
  try {
    await fs.writeFile(filePath, content, {
      encoding: "utf-8",
      flag: "wx",
    });
  } catch (err) {
    const anyErr = err as { code?: string };
    if (anyErr.code !== "EEXIST") throw err;
  }
}

async function hasGitRepo(dir: string): Promise<boolean> {
  try {
    await fs.stat(path.join(dir, ".git"));
    return true;
  } catch {
    return false;
  }
}

async function isGitAvailable(): Promise<boolean> {
  try {
    const result = await runCommandWithTimeout(["git", "--version"], { timeoutMs: 2_000 });
    return result.code === 0;
  } catch {
    return false;
  }
}

async function ensureGitRepo(dir: string, isBrandNewWorkspace: boolean) {
  if (!isBrandNewWorkspace) return;
  if (await hasGitRepo(dir)) return;
  if (!(await isGitAvailable())) return;
  try {
    await runCommandWithTimeout(["git", "init"], { cwd: dir, timeoutMs: 10_000 });
  } catch {
    // Ignore git init failures; workspace creation should still succeed.
  }
}

export async function ensureAgentWorkspace(params?: {
  dir?: string;
  ensureBootstrapFiles?: boolean;
}): Promise<{
  dir: string;
  agentsPath?: string;
  soulPath?: string;
  toolsPath?: string;
  identityPath?: string;
  userPath?: string;
  heartbeatPath?: string;
  bootstrapPath?: string;
}> {
  const rawDir = params?.dir?.trim() ? params.dir.trim() : DEFAULT_AGENT_WORKSPACE_DIR;
  const dir = resolveUserPath(rawDir);
  await fs.mkdir(dir, { recursive: true });

  if (!params?.ensureBootstrapFiles) return { dir };

  const agentsPath = path.join(dir, DEFAULT_AGENTS_FILENAME);
  const soulPath = path.join(dir, DEFAULT_SOUL_FILENAME);
  const toolsPath = path.join(dir, DEFAULT_TOOLS_FILENAME);
  const identityPath = path.join(dir, DEFAULT_IDENTITY_FILENAME);
  const userPath = path.join(dir, DEFAULT_USER_FILENAME);
  const heartbeatPath = path.join(dir, DEFAULT_HEARTBEAT_FILENAME);
  const bootstrapPath = path.join(dir, DEFAULT_BOOTSTRAP_FILENAME);

  const isBrandNewWorkspace = await (async () => {
    const paths = [agentsPath, soulPath, toolsPath, identityPath, userPath, heartbeatPath];
    const existing = await Promise.all(
      paths.map(async (p) => {
        try {
          await fs.access(p);
          return true;
        } catch {
          return false;
        }
      }),
    );
    return existing.every((v) => !v);
  })();

  const agentsTemplate = await loadTemplate(DEFAULT_AGENTS_FILENAME);
  const soulTemplate = await loadTemplate(DEFAULT_SOUL_FILENAME);
  const toolsTemplate = await loadTemplate(DEFAULT_TOOLS_FILENAME);
  const identityTemplate = await loadTemplate(DEFAULT_IDENTITY_FILENAME);
  const userTemplate = await loadTemplate(DEFAULT_USER_FILENAME);
  const heartbeatTemplate = await loadTemplate(DEFAULT_HEARTBEAT_FILENAME);
  const bootstrapTemplate = await loadTemplate(DEFAULT_BOOTSTRAP_FILENAME);

  await writeFileIfMissing(agentsPath, agentsTemplate);
  await writeFileIfMissing(soulPath, soulTemplate);
  await writeFileIfMissing(toolsPath, toolsTemplate);
  await writeFileIfMissing(identityPath, identityTemplate);
  await writeFileIfMissing(userPath, userTemplate);
  await writeFileIfMissing(heartbeatPath, heartbeatTemplate);
  if (isBrandNewWorkspace) {
    await writeFileIfMissing(bootstrapPath, bootstrapTemplate);
  }
  await ensureGitRepo(dir, isBrandNewWorkspace);

  return {
    dir,
    agentsPath,
    soulPath,
    toolsPath,
    identityPath,
    userPath,
    heartbeatPath,
    bootstrapPath,
  };
}

export async function loadWorkspaceBootstrapFiles(dir: string): Promise<WorkspaceBootstrapFile[]> {
  const resolvedDir = resolveUserPath(dir);

  const entries: Array<{
    name: WorkspaceBootstrapFileName;
    filePath: string;
  }> = [
    {
      name: DEFAULT_AGENTS_FILENAME,
      filePath: path.join(resolvedDir, DEFAULT_AGENTS_FILENAME),
    },
    {
      name: DEFAULT_SOUL_FILENAME,
      filePath: path.join(resolvedDir, DEFAULT_SOUL_FILENAME),
    },
    {
      name: DEFAULT_TOOLS_FILENAME,
      filePath: path.join(resolvedDir, DEFAULT_TOOLS_FILENAME),
    },
    {
      name: DEFAULT_IDENTITY_FILENAME,
      filePath: path.join(resolvedDir, DEFAULT_IDENTITY_FILENAME),
    },
    {
      name: DEFAULT_USER_FILENAME,
      filePath: path.join(resolvedDir, DEFAULT_USER_FILENAME),
    },
    {
      name: DEFAULT_HEARTBEAT_FILENAME,
      filePath: path.join(resolvedDir, DEFAULT_HEARTBEAT_FILENAME),
    },
    {
      name: DEFAULT_BOOTSTRAP_FILENAME,
      filePath: path.join(resolvedDir, DEFAULT_BOOTSTRAP_FILENAME),
    },
  ];

  const result: WorkspaceBootstrapFile[] = [];
  for (const entry of entries) {
    try {
      const content = await fs.readFile(entry.filePath, "utf-8");
      result.push({
        name: entry.name,
        path: entry.filePath,
        content,
        missing: false,
      });
    } catch {
      result.push({ name: entry.name, path: entry.filePath, missing: true });
    }
  }
  return result;
}

const SUBAGENT_BOOTSTRAP_ALLOWLIST = new Set([DEFAULT_AGENTS_FILENAME, DEFAULT_TOOLS_FILENAME]);

export function filterBootstrapFilesForSession(
  files: WorkspaceBootstrapFile[],
  sessionKey?: string,
): WorkspaceBootstrapFile[] {
  if (!sessionKey || !isSubagentSessionKey(sessionKey)) return files;
  return files.filter((file) => SUBAGENT_BOOTSTRAP_ALLOWLIST.has(file.name));
}

export type RepoContext = {
  owner: string;
  name: string;
  branch: string;
};

/**
 * Ensures a GitHub repository is cloned and checked out to the specified branch.
 * Uses `gh` CLI for authentication-aware cloning.
 * Returns the working directory path.
 */
export async function ensureRepoWorkspace(params: {
  repoContext: RepoContext;
  baseDir?: string;
}): Promise<{ dir: string; cloned: boolean; checkedOut: boolean }> {
  const { repoContext, baseDir } = params;
  const { owner, name, branch } = repoContext;

  const workspacesBase = baseDir || path.join(resolveDefaultAgentWorkspaceDir(), ".workspaces");
  await fs.mkdir(workspacesBase, { recursive: true });

  const repoDir = path.join(workspacesBase, owner, name);
  let cloned = false;
  let checkedOut = false;

  // Check if repo already exists
  const repoExists = await hasGitRepo(repoDir);

  if (!repoExists) {
    // Clone the repo using gh CLI
    await fs.mkdir(path.dirname(repoDir), { recursive: true });
    const cloneUrl = `https://github.com/${owner}/${name}.git`;

    try {
      // Try gh clone first (has auth)
      const ghResult = await runCommandWithTimeout(["gh", "repo", "clone", `${owner}/${name}`, repoDir], {
        timeoutMs: 120_000,
      });
      if (ghResult.code !== 0) {
        // Fallback to git clone (for public repos)
        const gitResult = await runCommandWithTimeout(["git", "clone", cloneUrl, repoDir], {
          timeoutMs: 120_000,
        });
        if (gitResult.code !== 0) {
          throw new Error(`Failed to clone ${owner}/${name}: ${gitResult.stderr || "unknown error"}`);
        }
      }
      cloned = true;
    } catch (err) {
      throw new Error(`Failed to clone repository ${owner}/${name}: ${String(err)}`);
    }
  }

  // Fetch latest changes
  try {
    await runCommandWithTimeout(["git", "fetch", "--all"], {
      cwd: repoDir,
      timeoutMs: 60_000,
    });
  } catch {
    // Fetch failures are non-fatal; we can work with local state
  }

  // Check current branch
  const currentBranchResult = await runCommandWithTimeout(["git", "rev-parse", "--abbrev-ref", "HEAD"], {
    cwd: repoDir,
    timeoutMs: 5_000,
  });
  const currentBranch = (currentBranchResult.stdout || "").trim();

  if (currentBranch !== branch) {
    // Try to checkout the branch
    const checkoutResult = await runCommandWithTimeout(["git", "checkout", branch], {
      cwd: repoDir,
      timeoutMs: 30_000,
    });

    if (checkoutResult.code !== 0) {
      // Branch might not exist locally, try to create from remote
      const checkoutRemoteResult = await runCommandWithTimeout(
        ["git", "checkout", "-b", branch, `origin/${branch}`],
        { cwd: repoDir, timeoutMs: 30_000 },
      );
      if (checkoutRemoteResult.code !== 0) {
        throw new Error(`Failed to checkout branch ${branch}: branch not found locally or on remote`);
      }
    }
    checkedOut = true;
  }

  return { dir: repoDir, cloned, checkedOut };
}