using Microsoft.Extensions.Configuration;
using System.Net.Http;
using System.IO;
using System.Text.Json;
using System.Text.Json.Serialization;
using YY.Admin.Core;
using YY.Admin.Core.Entity;
using YY.Admin.Core.Services;

namespace YY.Admin.Services.Service.Warehouse;

/// <summary>
/// 仓库数据只读服务：启动与重连时后台刷新远端写入缓存；GetAllAsync 优先读缓存，避免库区等业务每次打开都全量拉仓库。
/// </summary>
public class WarehouseService : IWarehouseService, ISingletonDependency
{
    private readonly IHttpClientFactory _httpClientFactory;
    private readonly IConfiguration _configuration;
    private readonly INetworkMonitor _networkMonitor;
    private readonly ILoggerService _logger;
    private readonly object _cacheLock = new();
    private readonly SemaphoreSlim _emptyLoadGate = new(1, 1);
    private readonly string _cacheFilePath;
    private List<MesXslWarehouse> _localCache = new();

    private static readonly JsonSerializerOptions _jsonOpts = new()
    {
        PropertyNameCaseInsensitive = true,
        PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
    };

    public WarehouseService(
        IHttpClientFactory httpClientFactory,
        IConfiguration configuration,
        INetworkMonitor networkMonitor,
        ILoggerService logger)
    {
        _httpClientFactory = httpClientFactory;
        _configuration = configuration;
        _networkMonitor = networkMonitor;
        _logger = logger;

        var appDataDir = Path.Combine(
            Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
            "YY.Admin", "sync-cache");
        Directory.CreateDirectory(appDataDir);
        _cacheFilePath = Path.Combine(appDataDir, "warehouse-cache.json");

        LoadCacheFromDisk();
        _logger.Information($"[仓库数据] 服务初始化，本地缓存={_localCache.Count} 条");

        if (_networkMonitor.IsOnline)
            _ = Task.Run(() => RefreshFromRemoteAsync(CancellationToken.None));

        _networkMonitor.StatusChanged += isOnline =>
        {
            if (isOnline)
                _ = Task.Run(() => RefreshFromRemoteAsync(CancellationToken.None));
        };
    }

    private string BaseUrl => (_configuration.GetValue<string>("JeecgIntegration:BaseUrl") ?? "http://localhost:8080/jeecg-boot").TrimEnd('/');
    private int DefaultTenantId => (int?)_configuration.GetValue<long?>("JeecgIntegration:DefaultTenantId") ?? 1002;

    public async Task<List<MesXslWarehouse>> GetAllAsync(CancellationToken ct = default)
    {
        lock (_cacheLock)
        {
            if (_localCache.Count > 0 || !_networkMonitor.IsOnline)
                return _localCache.ToList();
        }

        // 缓存为空且在线：仅此时阻塞拉远端（首次安装或清缓存后）
        await _emptyLoadGate.WaitAsync(ct).ConfigureAwait(false);
        try
        {
            lock (_cacheLock)
            {
                if (_localCache.Count > 0)
                    return _localCache.ToList();
            }

            if (!_networkMonitor.IsOnline)
            {
                lock (_cacheLock)
                    return _localCache.ToList();
            }

            try
            {
                await RefreshFromRemoteAsync(ct).ConfigureAwait(false);
            }
            catch
            {
                /* 登录前拉取失败等场景，仍返回当前缓存（可能仍为空） */
            }
        }
        finally
        {
            _emptyLoadGate.Release();
        }

        lock (_cacheLock)
            return _localCache.ToList();
    }

    private async Task RefreshFromRemoteAsync(CancellationToken ct)
    {
        try
        {
            var result = new List<MesXslWarehouse>();
            int pageNo = 1;
            const int pageSize = 500;
            while (true)
            {
                var url = $"{BaseUrl}/xslmes/mesXslWarehouse/anon/list?pageNo={pageNo}&pageSize={pageSize}&tenantId={DefaultTenantId}";
                using var client = _httpClientFactory.CreateClient("JeecgApi");
                var resp = await client.GetAsync(url, ct).ConfigureAwait(false);
                resp.EnsureSuccessStatusCode();
                var json = await resp.Content.ReadAsStringAsync(ct).ConfigureAwait(false);
                using var doc = JsonDocument.Parse(json);
                if (!doc.RootElement.TryGetProperty("result", out var resultEl)) break;
                if (resultEl.TryGetProperty("records", out var recordsEl))
                {
                    var page = recordsEl.Deserialize<List<MesXslWarehouse>>(_jsonOpts);
                    if (page != null) result.AddRange(page);
                }
                long total = 0;
                if (resultEl.TryGetProperty("total", out var totalEl)) total = totalEl.GetInt64();
                if (result.Count >= total || (resultEl.TryGetProperty("records", out var r2) && r2.GetArrayLength() < pageSize)) break;
                pageNo++;
            }

            lock (_cacheLock)
            {
                _localCache = result;
                SaveCacheToDiskUnsafe();
            }
            _logger.Information($"[仓库数据] 远端刷新成功，共 {result.Count} 条");
        }
        catch (Exception ex)
        {
            _logger.Warning($"[仓库数据] 远端刷新失败，使用缓存: {ex.Message}");
        }
    }

    private void LoadCacheFromDisk()
    {
        try
        {
            if (!File.Exists(_cacheFilePath)) return;
            var json = File.ReadAllText(_cacheFilePath);
            _localCache = JsonSerializer.Deserialize<List<MesXslWarehouse>>(json, _jsonOpts) ?? new();
        }
        catch { _localCache = new(); }
    }

    private void SaveCacheToDiskUnsafe()
    {
        try { File.WriteAllText(_cacheFilePath, JsonSerializer.Serialize(_localCache, _jsonOpts)); } catch { }
    }
}