using DealerSelection.Api.CommonUtil;
using DealerSelection.Api.Interface;
using DealerSelection.Api.Models;
using DealerSelection.Common.Interfaces.HttpClient;
using Microsoft.Extensions.Caching.Memory;
using Microsoft.Extensions.Logging;

namespace DealerSelection.Api;

public class MulesoftTokenApi : IMulesoftTokenApi
{
    private readonly ILogger _logger;
    private readonly IMemoryCache cache;
    IHttpClientHandler ClientHandler { get; }

    public MulesoftTokenApi(IMemoryCache cache, IHttpClientHandler clientHandler
        , ILogger<MulesoftTokenApi> logger)
    {
        this.cache = cache;
        ClientHandler = clientHandler;
        _logger = logger;
    }

    public async Task<string> FetchToken()
    {
        string token = string.Empty;
        try
        {
            // if cache doesn't contain 
            // an entry called TOKEN
            // error handling mechanism is mandatory
            if (!cache.TryGetValue("TOKEN", out token))
            {
                var tokenmodel = await GetTokenFromApi();
                // keep the value within cache for 
                // given amount of time
                // if value is not accessed within the expiry time
                // delete the entry from the cache
                if (tokenmodel.ExpiresIn > 0)
                {
                    var options = new MemoryCacheEntryOptions()
                            .SetAbsoluteExpiration(
                                  TimeSpan.FromSeconds(tokenmodel.ExpiresIn - 300));

                    cache.Set("TOKEN", tokenmodel.Value, options);

                    token = tokenmodel.Value;

                    _logger.LogInformation("MulesoftTokenApi at FetchToken - token Generated Successfully :- " + DateTime.Now);
                }
            }
        }
        catch (Exception ex)
        {
            _logger.LogError("MulesoftTokenApi Api:- FetchToken:- " + ex.Message.ToString());
        }
        return token;
    }

    private async Task<MulesoftToken> GetTokenFromApi()
    {
        // get api implementation happens here
        // returns a token model
        _logger.LogInformation("MulesoftTokenApi at GetTokenFromApi Started :- " + DateTime.Now);
        MulesoftToken token = await MuleSoftIntegration.generateToken(ClientHandler);
        return token;
    }
}