/**
 * Task name summarization using AI or romanization
 *
 * Generates concise English/romaji summaries for use in branch names and clone paths.
 */

import * as wanakana from 'wanakana';
import { loadGlobalConfig } from '../config/globalConfig.js';
import { getProvider, type ProviderType } from '../providers/index.js';
import { createLogger } from '../utils/debug.js';

const log = createLogger('summarize');

/**
 * Sanitize a string for use as git branch name and directory name.
 *
 * Git branch restrictions: no spaces, ~, ^, :, ?, *, [, \, .., @{, leading -
 * Directory restrictions: no /, \, :, *, ?, ", <, >, |
 *
 * This function allows only: a-z, 0-9, hyphen
 */
function sanitizeSlug(input: string, maxLength = 30): string {
  return input
    .trim()
    .toLowerCase()
    .replace(/[^a-z0-9-]/g, '-')  // Replace invalid chars with hyphen
    .replace(/-+/g, '-')          // Collapse multiple hyphens
    .replace(/^-+/, '')           // Remove leading hyphens
    .slice(0, maxLength)
    .replace(/-+$/, '');          // Remove trailing hyphens (after slice)
}

const SUMMARIZE_SYSTEM_PROMPT = `You are a slug generator. Given a task description, output ONLY a slug.

NEVER output sentences. NEVER start with "this", "the", "i", "we", or "it".
ALWAYS start with a verb: add, fix, update, refactor, implement, remove, etc.

Format: verb-noun (lowercase, hyphens, max 30 chars)

Input → Output:
認証機能を追加する → add-auth
Fix the login bug → fix-login-bug
ユーザー登録にメール認証を追加 → add-email-verification
worktreeを作るときブランチ名をAIで生成 → ai-branch-naming
レビュー画面に元の指示を表示する → show-original-instruction`;

export interface SummarizeOptions {
  /** Working directory for Claude execution */
  cwd: string;
  /** Model to use (optional, defaults to config or haiku) */
  model?: string;
  /** Use LLM for summarization (default: true). If false, uses romanization. */
  useLLM?: boolean;
}

/**
 * Convert Japanese text to romaji slug.
 * Handles hiragana, katakana, and passes through alphanumeric.
 * Kanji and other non-convertible characters become hyphens.
 */
function toRomajiSlug(text: string): string {
  // Convert to romaji (hiragana/katakana → romaji, kanji stays as-is)
  const romaji = wanakana.toRomaji(text, { customRomajiMapping: {} });
  return sanitizeSlug(romaji);
}

/**
 * Summarize a task name into a concise slug using AI or romanization.
 *
 * @param taskName - Original task name (can be in any language)
 * @param options - Summarization options
 * @returns Slug suitable for branch names (English if LLM, romaji if not)
 */
export async function summarizeTaskName(
  taskName: string,
  options: SummarizeOptions
): Promise<string> {
  const useLLM = options.useLLM ?? true;
  log.info('Summarizing task name', { taskName, useLLM });

  // Use romanization if LLM is disabled
  if (!useLLM) {
    const slug = toRomajiSlug(taskName);
    log.info('Task name romanized', { original: taskName, slug });
    return slug || 'task';
  }

  // Use LLM for summarization
  const globalConfig = loadGlobalConfig();
  const providerType = (globalConfig.provider as ProviderType) ?? 'claude';
  const model = options.model ?? globalConfig.model ?? 'haiku';

  const provider = getProvider(providerType);
  const response = await provider.call('summarizer', taskName, {
    cwd: options.cwd,
    model,
    systemPrompt: SUMMARIZE_SYSTEM_PROMPT,
    allowedTools: [],
  });

  const slug = sanitizeSlug(response.content);
  log.info('Task name summarized', { original: taskName, slug });

  return slug || 'task';
}