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

namespace YY.Admin.Services.Service.Print;

/// <summary>业务打印绑定：免密列表 + 本地缓存（只读）</summary>
public class PrintBizTemplateBindService : IPrintBizTemplateBindService
{
    private readonly IHttpClientFactory _httpClientFactory;
    private readonly IConfiguration _configuration;
    private readonly object _cacheLock = new();
    private List<PrintBizTemplateBind> _localCache = new();
    private readonly string _cacheFilePath;

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

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

    public PrintBizTemplateBindService(IHttpClientFactory httpClientFactory, IConfiguration configuration)
    {
        _httpClientFactory = httpClientFactory;
        _configuration = configuration;

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

        LoadCacheFromDisk();
    }

    public IReadOnlyList<PrintBizTemplateBind> GetCached()
    {
        lock (_cacheLock)
        {
            return _localCache.AsReadOnly();
        }
    }

    public async Task<IReadOnlyList<PrintBizTemplateBind>> ListAsync(CancellationToken ct = default)
    {
        try
        {
            return await RefreshCacheAsync(ct).ConfigureAwait(false);
        }
        catch
        {
            return GetCached();
        }
    }

    public async Task<IReadOnlyList<PrintBizTemplateBind>> RefreshCacheAsync(CancellationToken ct = default)
    {
        var client = _httpClientFactory.CreateClient("JeecgApi");
        var url = $"{BaseUrl}/print/bizTemplateBind/anon/list?pageSize=500&pageNo=1";
        var response = await client.GetAsync(url, ct).ConfigureAwait(false);
        response.EnsureSuccessStatusCode();
        var result = await response.Content.ReadFromJsonAsync<JeecgResult<JeecgPage<PrintBizTemplateBind>>>(JsonOpts, ct).ConfigureAwait(false);
        if (result?.Success != true)
            throw new InvalidOperationException(result?.Message ?? "后端返回失败");

        var records = result.Result?.Records ?? new List<PrintBizTemplateBind>();
        lock (_cacheLock)
        {
            _localCache = records;
            SaveCacheToDiskUnsafe();
        }
        return records.AsReadOnly();
    }

    public async Task<PrintBizTemplateBind?> GetByIdAsync(string id, CancellationToken ct = default)
    {
        if (string.IsNullOrWhiteSpace(id)) return null;
        try
        {
            var client = _httpClientFactory.CreateClient("JeecgApi");
            var url = $"{BaseUrl}/print/bizTemplateBind/anon/queryById?id={Uri.EscapeDataString(id)}";
            var response = await client.GetAsync(url, ct).ConfigureAwait(false);
            if (!response.IsSuccessStatusCode) return GetCachedById(id);
            var result = await response.Content.ReadFromJsonAsync<JeecgResult<PrintBizTemplateBind>>(JsonOpts, ct).ConfigureAwait(false);
            return result?.Success == true ? result.Result : GetCachedById(id);
        }
        catch
        {
            return GetCachedById(id);
        }
    }

    private PrintBizTemplateBind? GetCachedById(string id)
    {
        lock (_cacheLock)
        {
            return _localCache.FirstOrDefault(x => string.Equals(x.Id, id, StringComparison.OrdinalIgnoreCase));
        }
    }

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

    private void SaveCacheToDiskUnsafe()
    {
        try
        {
            var json = JsonSerializer.Serialize(_localCache, JsonOpts);
            File.WriteAllText(_cacheFilePath, json);
        }
        catch { /* 离线或磁盘异常时忽略 */ }
    }

    private record JeecgResult<T>(bool Success, T? Result, string? Message);
    private record JeecgPage<T>(List<T> Records, long Total);

    private sealed class NullableDateTimeJsonConverter : JsonConverter<DateTime?>
    {
        private static readonly string[] Formats =
        [
            "yyyy-MM-dd HH:mm:ss",
            "yyyy-MM-dd HH:mm:ss.fff",
            "yyyy-MM-ddTHH:mm:ss",
            "yyyy-MM-ddTHH:mm:ss.fff",
            "yyyy-MM-ddTHH:mm:ssZ",
            "yyyy-MM-ddTHH:mm:ss.fffZ"
        ];

        public override DateTime? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
        {
            if (reader.TokenType == JsonTokenType.Null) return null;
            if (reader.TokenType == JsonTokenType.String)
            {
                var raw = reader.GetString();
                if (string.IsNullOrWhiteSpace(raw)) return null;
                if (DateTime.TryParseExact(raw, Formats, System.Globalization.CultureInfo.InvariantCulture,
                        System.Globalization.DateTimeStyles.AssumeLocal, out var exact))
                    return exact;
                if (DateTime.TryParse(raw, out var fallback)) return fallback;
            }
            throw new JsonException($"无法将 JSON 值转换为 DateTime?，token={reader.TokenType}");
        }

        public override void Write(Utf8JsonWriter writer, DateTime? value, JsonSerializerOptions options)
        {
            if (value.HasValue) writer.WriteStringValue(value.Value.ToString("yyyy-MM-dd HH:mm:ss"));
            else writer.WriteNullValue();
        }
    }
}