using MesETL.App.Options;
using Microsoft.Extensions.DependencyInjection;
using StackExchange.Redis;

namespace MesETL.App.Cache;

public class RedisCache : ICacher
{
    private readonly IDatabase _db;

    public string KeyPrefix { get; set; }

    public RedisCache(IConnectionMultiplexer conn, int dataBase, string keyPrefix = "")
    {
        _db = conn.GetDatabase(dataBase);
        KeyPrefix = keyPrefix;
    }

    public async Task<string?> GetStringAsync(string key)
    {
        var value = await _db.StringGetAsync($"{KeyPrefix}{key}");
        return !value.HasValue ? null : value.ToString();
    }

    public async Task SetStringAsync(string key, string value)
    {
        if (!await _db.StringSetAsync($"{KeyPrefix}{key}", value))
            throw new RedisCommandException("设置Redis缓存失败");
    }

    public Task<bool> ExistsAsync(string key)
    {
        return _db.KeyExistsAsync($"{KeyPrefix}{key}");
    }

    public Task SetHashAsync(string key, IReadOnlyDictionary<string, string> hash)
    {
        return _db.HashSetAsync($"{KeyPrefix}{key}", hash.Select(pair => new HashEntry(pair.Key, pair.Value)).ToArray());
    }

    public async Task<Dictionary<string, string>> GetHashAsync(string key)
    {
        var entries = await _db.HashGetAllAsync($"{KeyPrefix}{key}");
        var result = new Dictionary<string, string>();
        foreach (var entry in entries)
        {
            result.Add(entry.Name.ToString(), entry.Value.ToString());
        }

        return result;
    }
}

public static class RedisCacheExtensions
{
    public static IServiceCollection AddRedisCache(this IServiceCollection services, RedisCacheOptions options)
    {
        var conn = ConnectionMultiplexer.Connect(options.Configuration 
                                                 ?? throw new ApplicationException("未配置Redis连接字符串"));
        services.AddSingleton<ICacher>(new RedisCache(conn, options.Database, options.InstanceName));
        return services;
    }
}