import { readFile } from 'node:fs/promises';
import path from 'node:path';
import {
  BUNDLED_CODING_SKILL_IDS,
  type BundledCodingSkillId,
} from '../../shared/coding-skills';
import type {
  ProductCodingCommand,
  ProductCodingSkill,
  ProductPiCommandInput,
} from '../../shared/coding-product-tools';

export type {
  ProductCodingCommand,
  ProductCodingSkill,
  ProductPiCommandInput,
} from '../../shared/coding-product-tools';

const MAKELORE_COMMANDS: readonly ProductCodingCommand[] = [
  { name: 'models', title: '切换模型', description: '切换当前会话后续轮次使用的模型', source: 'makelore' },
  { name: 'thinking', title: '思考强度', description: '设置当前会话的思考强度', source: 'makelore' },
  { name: 'compact', title: '压缩会话', description: '使用当前模型总结会话上下文', source: 'makelore' },
  { name: 'fork', title: '分叉会话', description: '从当前用户消息创建新的产品会话', source: 'makelore' },
  { name: 'recover', title: '恢复会话', description: '重新创建当前会话 worker 并恢复状态', source: 'makelore' },
] as const;

const COMMAND_NAME_PATTERN = /^[A-Za-z0-9][A-Za-z0-9._:-]{0,63}$/;

function frontmatterScalar(content: string, key: string): string | undefined {
  const block = content.match(/^---\s*\r?\n([\s\S]*?)\r?\n---(?:\r?\n|$)/)?.[1];
  if (!block) return undefined;
  const line = block.split(/\r?\n/).find((candidate) => candidate.startsWith(`${key}:`));
  if (!line) return undefined;
  const value = line.slice(key.length + 1).trim();
  if ((value.startsWith('"') && value.endsWith('"'))
    || (value.startsWith("'") && value.endsWith("'"))) {
    return value.slice(1, -1).trim() || undefined;
  }
  return value || undefined;
}

function selectedSkillIds(value: readonly string[]): Set<BundledCodingSkillId> {
  const allowed = new Set<string>(BUNDLED_CODING_SKILL_IDS);
  const selected = new Set<BundledCodingSkillId>();
  for (const raw of value) {
    const id = raw.trim();
    if (!allowed.has(id)) throw new Error(`Unknown bundled coding skill: ${id}`);
    selected.add(id as BundledCodingSkillId);
  }
  return selected;
}

export async function listProductCodingSkills(
  bundledSkillsDir: string,
  selectedIds: readonly string[] = [],
): Promise<ProductCodingSkill[]> {
  const selected = selectedSkillIds(selectedIds);
  return await Promise.all(BUNDLED_CODING_SKILL_IDS.map(async (id) => {
    const content = await readFile(path.join(bundledSkillsDir, id, 'SKILL.md'), 'utf8');
    return {
      id,
      name: frontmatterScalar(content, 'name') ?? id,
      description: frontmatterScalar(content, 'description') ?? '',
      selected: selected.has(id),
    };
  }));
}

export function buildProductCodingCommandCatalog(
  skills: readonly ProductCodingSkill[],
  piCommands: readonly ProductPiCommandInput[] = [],
): ProductCodingCommand[] {
  const commands = [...MAKELORE_COMMANDS];
  const used = new Set(commands.map((command) => command.name.toLocaleLowerCase()));
  for (const command of piCommands) {
    const name = command.name.trim();
    const key = name.toLocaleLowerCase();
    if (!COMMAND_NAME_PATTERN.test(name) || used.has(key)) continue;
    used.add(key);
    commands.push({
      name,
      title: name,
      description: command.description?.trim() || 'Pi 命令',
      source: 'pi',
    });
  }
  for (const skill of skills) {
    const key = skill.id.toLocaleLowerCase();
    if (!skill.selected || used.has(key)) continue;
    used.add(key);
    commands.push({
      name: skill.id,
      title: skill.name,
      description: skill.description || '项目技能',
      source: 'skill',
      skillId: skill.id,
    });
  }
  return commands;
}