using System.Collections.Concurrent;
using Microsoft.Playwright;

namespace dy.net.service
{
    public class DyQrCodeService
    {
        private static readonly ConcurrentDictionary<string, QrSession> _sessions = new();

        private class QrSession
        {
            public IPlaywright Playwright { get; set; }
            public IBrowser Browser { get; set; }
            public IBrowserContext Context { get; set; }
            public IPage Page { get; set; }
            public DateTime CreatedAt { get; set; } = DateTime.Now;
            public string FinalCookies { get; set; }
            public string SecUserId { get; set; }
        }

        private const string LoginUrl = "https://creator.douyin.com/creator-micro/login";
        // QR 码图片的 class 名含 qrcode_img（后缀随版本变化，用属性选择器匹配）
        private const string QrSelector = "img[class*='qrcode_img']";

        public async Task<(string token, string qrBase64)> GetQrCodeAsync()
        {
            CleanExpiredSessions();

            var playwright = await Playwright.CreateAsync();
            var browser = await playwright.Chromium.LaunchAsync(new BrowserTypeLaunchOptions
            {
                Headless = true,
                Args = new[] { "--no-sandbox", "--disable-setuid-sandbox", "--disable-dev-shm-usage" }
            });
            var context = await browser.NewContextAsync(new BrowserNewContextOptions
            {
                UserAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36"
            });
            var page = await context.NewPageAsync();

            await page.GotoAsync(LoginUrl, new PageGotoOptions { Timeout = 15000 });
            await page.WaitForSelectorAsync(QrSelector, new PageWaitForSelectorOptions { Timeout = 10000 });

            // img.src 已经是 data:image/png;base64,... 直接取用
            var src = await page.EvaluateAsync<string>($"() => document.querySelector(\"{QrSelector}\").src");
            var qrBase64 = src.Replace("data:image/png;base64,", "");

            var token = Guid.NewGuid().ToString("N");
            _sessions[token] = new QrSession
            {
                Playwright = playwright,
                Browser = browser,
                Context = context,
                Page = page
            };

            return (token, qrBase64);
        }

        public async Task<(int status, string cookies, string secUserId)> CheckStatusAsync(string token)
        {
            if (!_sessions.TryGetValue(token, out var session))
                return (-1, null, null);

            if (DateTime.Now - session.CreatedAt > TimeSpan.FromMinutes(5))
            {
                await CloseSessionAsync(token, session);
                return (-1, null, null);
            }

            // 已经登录过，直接返回缓存
            if (session.FinalCookies != null)
                return (3, session.FinalCookies, session.SecUserId);

            var url = session.Page.Url;

            // 还在登录页
            if (url.Contains("/creator-micro/login") || url.Contains("sso.douyin.com"))
            {
                // 判断是否已扫码（页面出现"确认"或"已扫码"文字）
                var scanned = await session.Page.EvaluateAsync<bool>(
                    "() => { const t = document.body.innerText; return t.includes('已扫码') || t.includes('确认登录'); }"
                );
                return (scanned ? 2 : 1, null, null);
            }

            // URL 已离开登录页，说明登录成功
            var browserCookies = await session.Context.CookiesAsync(new[]
            {
                "https://creator.douyin.com",
                "https://www.douyin.com",
                "https://sso.douyin.com"
            });
            var cookieStr = string.Join("; ", browserCookies.Select(c => $"{c.Name}={c.Value}"));

            // 尝试从页面获取 sec_user_id
            var secUserId = await GetSecUserIdAsync(session.Page);

            session.FinalCookies = cookieStr;
            session.SecUserId = secUserId;

            // 登录完成后关闭浏览器释放资源
            _ = Task.Run(async () => await CloseSessionAsync(token, session));

            return (3, cookieStr, secUserId);
        }

        public (string cookies, string secUserId) GetSessionResult(string token)
        {
            if (_sessions.TryGetValue(token, out var session))
                return (session.FinalCookies ?? "", session.SecUserId ?? "");
            return ("", "");
        }

        public void RemoveSession(string token)
        {
            if (_sessions.TryRemove(token, out var session))
                _ = Task.Run(async () => await CloseSessionAsync(token, session));
        }

        private static async Task<string> GetSecUserIdAsync(IPage page)
        {
            try
            {
                // 从页面 URL 或 API 提取 sec_user_id
                var resp = await page.EvaluateAsync<string>(
                    "async () => { const r = await fetch('/web/api/userinfo/'); const j = await r.json(); return j?.data?.sec_uid || j?.sec_uid || ''; }"
                );
                return resp ?? "";
            }
            catch
            {
                return "";
            }
        }

        private static async Task CloseSessionAsync(string token, QrSession session)
        {
            _sessions.TryRemove(token, out _);
            try { await session.Browser?.CloseAsync(); } catch { }
            try { session.Playwright?.Dispose(); } catch { }
        }

        private static void CleanExpiredSessions()
        {
            var expired = _sessions
                .Where(kv => DateTime.Now - kv.Value.CreatedAt > TimeSpan.FromMinutes(6))
                .ToList();
            foreach (var kv in expired)
                _ = Task.Run(async () => await CloseSessionAsync(kv.Key, kv.Value));
        }
    }
}