import type { ProfileIR } from '../ir.js';
import { SHADOWROCKET_LAN_RULES } from './shadowrocket-lan.js';

/**
 * ShadowRocket 的 conf 语法没有引号机制：策略名一律裸写，含空格/emoji 均可；
 * 加引号会被当作名字的一部分，导致规则指向不存在的策略组而整条失效。
 * 逗号是唯一分隔符，名字里的逗号无法表达，只能剔除。
 */
function policyName(name: string): string {
  return name.replace(/[",]/g, '').trim();
}

/**
 * ShadowRocket 的 [General] 只保留它认识的通用键——模板里的 Surge 专有键
 * （all-hybrid / udp-priority / http-api / compatibility-mode 等）会被过滤掉。
 */
const SR_GENERAL_KEYS = new Set([
  'bypass-system',
  'skip-proxy',
  'bypass-tun',
  'dns-server',
  'fallback-dns-server',
  'ipv6',
  'prefer-ipv6',
  'dns-direct-system',
  'icmp-auto-reply',
  'always-real-ip',
  'hijack-dns',
  'udp-policy-not-supported-behaviour',
  'interface-mode',
]);

function shadowrocketGeneral(surgeGeneral: string): string {
  const lines: string[] = [];
  for (const raw of surgeGeneral.split(/\r?\n/)) {
    const line = raw.trim();
    if (!line || line.startsWith('#') || line.startsWith('//')) continue;
    const key = line.split('=')[0].trim();
    if (SR_GENERAL_KEYS.has(key)) lines.push(line);
  }
  // ShadowRocket 的常用默认值，模板里没有就补上
  if (!lines.some((l) => l.startsWith('bypass-system'))) lines.push('bypass-system = true');
  if (!lines.some((l) => l.startsWith('ipv6'))) lines.push('ipv6 = false');
  if (!lines.some((l) => l.startsWith('dns-server'))) lines.push('dns-server = 223.5.5.5, 119.29.29.29');
  return lines.join('\n');
}

/** 尚未验证 Shadowrocket 配置语法的类型；这是生成器的保守范围，不是客户端能力断言。 */
const SR_UNSUPPORTED_RULE_TYPES = new Set(['DOMAIN-SET', 'AND', 'OR', 'NOT', 'URL-REGEX', 'PROTOCOL']);

export interface ShadowrocketConfOutput {
  content: string;
  skippedRules: string[];
}

/**
 * 生成 ShadowRocket 配置文件：策略组 + 规则，不含节点。
 * 节点由「节点订阅」单独导入。ShadowRocket 没有 Surge 的 `use=` 订阅引用语法，
 * 策略组收节点只能靠 `policy-regex-filter` 从 App 内全部节点里筛选，
 * 因此订阅在 App 里叫什么名字都可以。
 */
export function generateShadowrocketConf(ir: ProfileIR, opts: { convertBaseUrl?: string } = {}): ShadowrocketConfOutput {
  const lines: string[] = [];

  lines.push('# 由 Proxy Station 生成的 ShadowRocket 配置（策略组 + 规则）');
  lines.push('# 节点请另行导入「节点订阅」');
  lines.push('');
  lines.push('[General]');
  lines.push(shadowrocketGeneral(ir.sections['General'] ?? ''));

  lines.push('', '[Proxy Group]');
  for (const g of ir.groups) {
    const parts: string[] = [g.type];
    const members = [...new Set(g.members.map((m) => policyName(m.name)))];
    parts.push(...(members.length ? members : !g.filterRegex && !g.includeAllNodes ? ['DIRECT'] : []));
    if (g.type !== 'select') {
      parts.push(`url=${g.testUrl || 'http://cp.cloudflare.com/generate_204'}`);
      if (g.interval) parts.push(`interval=${g.interval}`);
      if (g.type === 'url-test' && g.tolerance !== null) parts.push(`tolerance=${g.tolerance}`);
    }
    // policy-regex-filter 从 App 内全部节点里筛选；「收纳全部节点」用全匹配正则
    const filter = g.filterRegex || (g.includeAllNodes ? '.*' : null);
    if (filter) parts.push(`policy-regex-filter=${filter}`);
    lines.push(`${policyName(g.name)} = ${parts.join(', ')}`);
  }

  const skippedRules: string[] = [];
  lines.push('', '[Rule]');
  for (const r of ir.rules) {
    if (r.type === 'FINAL') {
      lines.push(['FINAL', policyName(r.policy)].join(','));
      continue;
    }
    if (r.type === 'DOMAIN-SET' && r.ruleset?.clashBehavior === 'domain' && opts.convertBaseUrl) {
      const url = `${opts.convertBaseUrl}/ruleset/${encodeURIComponent(r.ruleset.id)}.list`;
      lines.push(['RULE-SET', url, policyName(r.policy), ...r.params].join(','));
      continue;
    }
    if (r.type === 'RULE-SET' && !r.ruleset && r.value === 'LAN') {
      lines.push(...SHADOWROCKET_LAN_RULES.map((rule) => [rule, policyName(r.policy), ...r.params].join(',')));
      continue;
    }
    // An absolute macOS app-bundle path cannot identify an iOS application.
    if (r.type === 'PROCESS-NAME' && /^\/Applications\/.*\.app(?:\/|$)/.test(r.value ?? '')) {
      skippedRules.push(`${r.type},${r.value},${r.policy}`);
      continue;
    }
    if (SR_UNSUPPORTED_RULE_TYPES.has(r.type)) {
      skippedRules.push(`${r.type},${r.ruleset ? r.ruleset.name : r.value},${r.policy}`);
      continue;
    }
    const value = r.ruleset ? r.ruleset.surgeUrl : r.value;
    lines.push([r.type, value, policyName(r.policy), ...r.params].join(','));
  }

  for (const section of ['Host', 'URL Rewrite', 'MITM']) {
    if (ir.sections[section]) lines.push('', `[${section}]`, ir.sections[section]);
  }

  return { content: lines.join('\n') + '\n', skippedRules };
}