/**
 * @license
 * Copyright Vybestack LLC, 2026
 * SPDX-License-Identifier: Apache-2.0
 */

import { SettingScope } from '../config/settings.js';
import type { SkillActionResult } from './skillSettings.js';
import {
  loadSkillsFromDir,
  type SkillDefinition,
} from '@vybestack/llxprt-code-core';
import { Storage } from '@vybestack/llxprt-code-settings';
import { cloneFromGit } from '../config/extensions/github.js';
import { extractZipSafe } from './zipExtract.js';
import * as fs from 'node:fs/promises';
import * as path from 'node:path';
import * as os from 'node:os';
import { firstNonEmptyString } from './coalesce.js';

/**
 * Shared logic for building the core skill action message while allowing the
 * caller to control how each scope and its path are rendered (e.g., bolding or
 * dimming).
 *
 * This function ONLY returns the description of what happened. It is up to the
 * caller to append any interface-specific guidance (like "Use /skills reload"
 * or "Restart required").
 */
export function renderSkillActionFeedback(
  result: SkillActionResult,
  formatScope: (label: string, path: string) => string,
): string {
  const { skillName, action, status, error } = result;

  if (status === 'error') {
    return firstNonEmptyString(
      error,
      `An error occurred while attempting to ${action} skill "${skillName}".`,
    );
  }

  if (status === 'no-op') {
    return `Skill "${skillName}" is already ${action === 'enable' ? 'enabled' : 'disabled'}.`;
  }

  const isEnable = action === 'enable';
  const actionVerb = isEnable ? 'enabled' : 'disabled';
  const preposition = isEnable
    ? 'by removing it from the disabled list in'
    : 'by adding it to the disabled list in';

  const formatScopeItem = (s: { scope: SettingScope; path: string }) => {
    const label =
      s.scope === SettingScope.Workspace ? 'workspace' : s.scope.toLowerCase();
    return formatScope(label, s.path);
  };

  const totalAffectedScopes = [
    ...result.modifiedScopes,
    ...result.alreadyInStateScopes,
  ];

  if (totalAffectedScopes.length === 2) {
    const s1 = formatScopeItem(totalAffectedScopes[0]);
    const s2 = formatScopeItem(totalAffectedScopes[1]);

    if (isEnable) {
      return `Skill "${skillName}" ${actionVerb} ${preposition} ${s1} and ${s2} settings.`;
    }
    return `Skill "${skillName}" is now disabled in both ${s1} and ${s2} settings.`;
  }

  const s = formatScopeItem(totalAffectedScopes[0]);
  return `Skill "${skillName}" ${actionVerb} ${preposition} ${s} settings.`;
}

/**
 * Resolves the source path for a skill, cloning or extracting as needed.
 * Returns the resolved local path and the temp directory to clean up (if any).
 */
async function resolveSkillSource(
  source: string,
  onLog: (msg: string) => void,
): Promise<{ sourcePath: string; tempDirToClean: string | undefined }> {
  const isGitUrl =
    source.startsWith('git@') ||
    source.startsWith('http://') ||
    source.startsWith('https://');

  const isSkillFile = source.toLowerCase().endsWith('.skill');

  if (isGitUrl) {
    const tempDir = await fs.mkdtemp(path.join(os.tmpdir(), 'llxprt-skill-'));
    onLog(`Cloning skill from ${source}...`);
    await cloneFromGit({ source, type: 'git' }, tempDir);
    return { sourcePath: tempDir, tempDirToClean: tempDir };
  }

  if (isSkillFile) {
    const tempDir = await fs.mkdtemp(path.join(os.tmpdir(), 'llxprt-skill-'));
    onLog(`Extracting skill from ${source}...`);
    await extractZipSafe(source, tempDir);
    return { sourcePath: tempDir, tempDirToClean: tempDir };
  }

  return { sourcePath: source, tempDirToClean: undefined };
}

/**
 * Copies resolved skills into the target directory, overwriting if needed.
 */
async function copySkillsToTarget(
  skills: SkillDefinition[],
  targetDir: string,
  onLog: (msg: string) => void,
): Promise<Array<{ name: string; location: string }>> {
  const installedSkills: Array<{ name: string; location: string }> = [];

  for (const skill of skills) {
    const skillName = skill.name;
    const skillDir = path.dirname(skill.location);
    const destPath = path.join(targetDir, skillName);

    const exists = await fs.stat(destPath).catch(() => null);
    if (exists) {
      onLog(`Skill "${skillName}" already exists. Overwriting...`);
      await fs.rm(destPath, { recursive: true, force: true });
    }

    await fs.cp(skillDir, destPath, { recursive: true });
    installedSkills.push({ name: skillName, location: destPath });
  }

  return installedSkills;
}

/**
 * Central logic for installing a skill from a remote URL or local path.
 */
export async function installSkill(
  source: string,
  scope: 'user' | 'workspace',
  subpath: string | undefined,
  onLog: (msg: string) => void,
  requestConsent: (
    skills: SkillDefinition[],
    targetDir: string,
  ) => Promise<boolean>,
): Promise<Array<{ name: string; location: string }>> {
  const { sourcePath: rawSourcePath, tempDirToClean } =
    await resolveSkillSource(source, onLog);

  try {
    let sourcePath = rawSourcePath;
    if (subpath) {
      sourcePath = path.join(sourcePath, subpath);
    }

    sourcePath = path.resolve(sourcePath);

    if (tempDirToClean) {
      const tempRoot = path.resolve(tempDirToClean);
      const relative = path.relative(tempRoot, sourcePath);
      if (relative.startsWith('..') || path.isAbsolute(relative)) {
        throw new Error('Invalid path: Directory traversal not allowed.');
      }
    }

    onLog(`Searching for skills in ${sourcePath}...`);
    const skills = await loadSkillsFromDir(sourcePath);

    if (skills.length === 0) {
      const subpathMessage = subpath ? ` at path "${subpath}"` : '';
      throw new Error(
        `No valid skills found in ${source}${subpathMessage}. Ensure a SKILL.md file exists with valid frontmatter.`,
      );
    }

    const workspaceDir = process.cwd();
    const storage = new Storage(workspaceDir);
    const targetDir =
      scope === 'workspace'
        ? storage.getProjectSkillsDir()
        : Storage.getUserSkillsDir();

    if (!(await requestConsent(skills, targetDir))) {
      throw new Error('Skill installation cancelled by user.');
    }

    await fs.mkdir(targetDir, { recursive: true });
    return await copySkillsToTarget(skills, targetDir, onLog);
  } finally {
    if (tempDirToClean) {
      await fs.rm(tempDirToClean, { recursive: true, force: true });
    }
  }
}

/**
 * Central logic for uninstalling a skill by name.
 */
export async function uninstallSkill(
  name: string,
  scope: 'user' | 'workspace',
): Promise<{ location: string } | null> {
  const workspaceDir = process.cwd();
  const storage = new Storage(workspaceDir);
  const targetDir =
    scope === 'workspace'
      ? storage.getProjectSkillsDir()
      : Storage.getUserSkillsDir();

  const skillPath = path.join(targetDir, name);

  const exists = await fs.stat(skillPath).catch(() => null);

  if (!exists) {
    return null;
  }

  await fs.rm(skillPath, { recursive: true, force: true });
  return { location: skillPath };
}