import path from "node:path";

import { isDirectory, isFile, pathExists, listImmediateDirectories, readJson } from "../lib/files.js";

export async function resolveTarget(inputPath) {
  const resolvedPath = path.resolve(inputPath);
  if (await isFile(resolvedPath)) {
    if (path.basename(resolvedPath) === "SKILL.md") {
      return {
        kind: "skill",
        path: path.dirname(resolvedPath),
        entryPath: resolvedPath,
        name: path.basename(path.dirname(resolvedPath)),
      };
    }
    if (
      path.basename(resolvedPath) === "plugin.json" &&
      path.basename(path.dirname(resolvedPath)) === ".codex-plugin"
    ) {
      return {
        kind: "plugin",
        path: path.dirname(path.dirname(resolvedPath)),
        entryPath: resolvedPath,
        name: path.basename(path.dirname(path.dirname(resolvedPath))),
      };
    }

    return {
      kind: "file",
      path: resolvedPath,
      entryPath: resolvedPath,
      name: path.basename(resolvedPath),
    };
  }

  if (!(await isDirectory(resolvedPath))) {
    throw new Error(`Target path does not exist: ${resolvedPath}`);
  }

  const pluginManifestPath = path.join(resolvedPath, ".codex-plugin", "plugin.json");
  if (await pathExists(pluginManifestPath)) {
    return {
      kind: "plugin",
      path: resolvedPath,
      entryPath: pluginManifestPath,
      name: path.basename(resolvedPath),
    };
  }

  const skillPath = path.join(resolvedPath, "SKILL.md");
  if (await pathExists(skillPath)) {
    return {
      kind: "skill",
      path: resolvedPath,
      entryPath: skillPath,
      name: path.basename(resolvedPath),
    };
  }

  return {
    kind: "directory",
    path: resolvedPath,
    entryPath: resolvedPath,
    name: path.basename(resolvedPath),
  };
}

export async function discoverPluginSkillDirectories(pluginRoot, manifest) {
  const configuredPath = manifest?.skills ? manifest.skills.replace(/^\.\//, "") : "skills";
  const skillsRoot = path.join(pluginRoot, configuredPath);
  if (!(await isDirectory(skillsRoot))) {
    return [];
  }

  const candidates = await listImmediateDirectories(skillsRoot);
  const directories = [];
  for (const candidate of candidates) {
    const skillFile = path.join(candidate, "SKILL.md");
    if (await pathExists(skillFile)) {
      directories.push(candidate);
    }
  }
  return directories;
}

export async function loadPluginManifest(pluginRoot) {
  const manifestPath = path.join(pluginRoot, ".codex-plugin", "plugin.json");
  return readJson(manifestPath);
}