/**
 * FILE `glob` handler: expands a glob pattern to matching file paths, rooted at an
 * explicit path or the conversation's SessionCwdService cwd, with SandboxService
 * validation on the search root.
 */
import * as fs from "node:fs/promises";
import * as path from "node:path";

import {
  type ActionResult,
  logger as coreLogger,
  type HandlerCallback,
  type IAgentRuntime,
  type Memory,
  type State,
} from "@elizaos/core";

import {
  failureToActionResult,
  readStringParam,
  successActionResult,
} from "../lib/format.js";
import type { SandboxService } from "../services/sandbox-service.js";
import type { SessionCwdService } from "../services/session-cwd-service.js";
import {
  CODING_TOOLS_LOG_PREFIX,
  SANDBOX_SERVICE,
  SESSION_CWD_SERVICE,
} from "../types.js";

const RESULT_LIMIT = 100;
const EXCLUDED_DIR_NAMES = new Set([
  ".git",
  "node_modules",
  "dist",
  ".turbo",
  ".cache",
]);

interface NodeFsGlobModule {
  glob: (
    pattern: string | string[],
    options?: { cwd?: string; exclude?: (path: string) => boolean },
  ) => AsyncIterable<string>;
}

function getNodeFsGlob(): NodeFsGlobModule["glob"] | undefined {
  const candidate = (fs as Partial<NodeFsGlobModule>).glob;
  return typeof candidate === "function" ? candidate : undefined;
}

function globToRegExp(pattern: string): RegExp {
  let regex = "";
  let i = 0;
  while (i < pattern.length) {
    const ch = pattern[i];
    if (ch === "*") {
      if (pattern[i + 1] === "*") {
        const after = pattern[i + 2];
        if (after === "/") {
          regex += "(?:.*/)?";
          i += 3;
        } else {
          regex += ".*";
          i += 2;
        }
      } else {
        regex += "[^/]*";
        i += 1;
      }
    } else if (ch === "?") {
      regex += "[^/]";
      i += 1;
    } else if (ch === ".") {
      regex += "\\.";
      i += 1;
    } else if ("+^$()|[]{}\\".includes(ch ?? "")) {
      regex += `\\${ch}`;
      i += 1;
    } else {
      regex += ch;
      i += 1;
    }
  }
  return new RegExp(`^${regex}$`);
}

async function walkFallback(root: string, pattern: string): Promise<string[]> {
  const matcher = globToRegExp(pattern);
  const results: string[] = [];

  async function walk(dir: string): Promise<void> {
    let names: string[];
    try {
      names = await fs.readdir(dir);
    } catch {
      // error-policy:J6 best-effort walk; a directory that became unreadable
      // (permissions, race) is skipped so the remaining tree is still globbed.
      return;
    }
    for (const name of names) {
      if (EXCLUDED_DIR_NAMES.has(name)) continue;
      const abs = path.join(dir, name);
      try {
        const st = await fs.lstat(abs);
        if (st.isDirectory()) {
          await walk(abs);
        } else if (st.isFile()) {
          const rel = path.relative(root, abs).split(path.sep).join("/");
          if (matcher.test(rel)) {
            results.push(abs);
          }
        }
      } catch {
        // error-policy:J6 best-effort per-entry lstat; an entry that vanished
        // or is unreadable is skipped rather than aborting the whole walk.
      }
    }
  }

  await walk(root);
  return results;
}

async function nodeGlob(
  glob: NodeFsGlobModule["glob"],
  root: string,
  pattern: string,
): Promise<string[]> {
  const out: string[] = [];
  const iter = glob(pattern, {
    cwd: root,
    exclude: (p: string) => {
      const segments = p.split(/[\\/]/);
      return segments.some((seg) => EXCLUDED_DIR_NAMES.has(seg));
    },
  });
  for await (const entry of iter) {
    out.push(path.isAbsolute(entry) ? entry : path.join(root, entry));
  }
  return out;
}

export async function globHandler(
  runtime: IAgentRuntime,
  message: Memory,
  _state: State | undefined,
  options: unknown,
  callback?: HandlerCallback,
): Promise<ActionResult> {
  const conversationId =
    message.roomId !== undefined && message.roomId !== null
      ? String(message.roomId)
      : undefined;
  if (!conversationId) {
    return failureToActionResult({
      reason: "missing_param",
      message: "no roomId",
    });
  }

  const pattern = readStringParam(options, "pattern");
  if (!pattern || pattern.length === 0) {
    return failureToActionResult({
      reason: "missing_param",
      message: "pattern is required",
    });
  }

  const sandbox = runtime.getService(SANDBOX_SERVICE) as InstanceType<
    typeof SandboxService
  > | null;
  const session = runtime.getService(SESSION_CWD_SERVICE) as InstanceType<
    typeof SessionCwdService
  > | null;
  if (!sandbox || !session) {
    return failureToActionResult({
      reason: "internal",
      message: "coding-tools services unavailable",
    });
  }

  const requestedPath = readStringParam(options, "path");
  const targetPath =
    requestedPath ?? (await session.getExistingCwd(conversationId)).cwd;

  const validation = await sandbox.validatePath(conversationId, targetPath);
  if (validation.ok === false) {
    const reason =
      validation.reason === "blocked" ? "path_blocked" : "invalid_param";
    return failureToActionResult({ reason, message: validation.message });
  }
  const root = validation.resolved;

  let candidates: string[];
  const builtinGlob = getNodeFsGlob();
  if (builtinGlob) {
    try {
      candidates = await nodeGlob(builtinGlob, root, pattern);
    } catch (err) {
      // error-policy:J4 designed degrade; the native `node:fs.glob` and the
      // manual walker compute the same match set, so a native-glob failure
      // falls back to the walker with a warning rather than failing the action.
      const msg = err instanceof Error ? err.message : String(err);
      coreLogger.warn(
        `${CODING_TOOLS_LOG_PREFIX} GLOB node:fs.glob failed (${msg}); falling back to walker`,
      );
      candidates = await walkFallback(root, pattern);
    }
  } else {
    candidates = await walkFallback(root, pattern);
  }

  const stats = await Promise.all(
    candidates.map(async (filePath) => {
      try {
        const stat = await fs.stat(filePath);
        if (!stat.isFile()) return undefined;
        return { filePath, mtimeMs: stat.mtimeMs };
      } catch {
        // error-policy:J6 best-effort mtime enrichment; a candidate that
        // vanished between glob and stat drops out of the sorted result.
        return undefined;
      }
    }),
  );

  const filtered = stats.filter(
    (entry): entry is { filePath: string; mtimeMs: number } =>
      entry !== undefined,
  );
  filtered.sort((a, b) => b.mtimeMs - a.mtimeMs);

  const truncated = filtered.length > RESULT_LIMIT;
  const limited = filtered
    .slice(0, RESULT_LIMIT)
    .map((entry) => entry.filePath);

  const header = `${limited.length} files (truncated=${truncated})`;
  const text =
    limited.length === 0 ? header : `${header}\n${limited.join("\n")}`;

  coreLogger.debug(
    `${CODING_TOOLS_LOG_PREFIX} GLOB pattern=${JSON.stringify(pattern)} root=${root} found=${limited.length} truncated=${truncated}`,
  );

  if (callback) await callback({ text });

  return successActionResult(text, {
    files: limited,
    truncated,
  });
}