using System.Threading.Tasks;
using AcaMate.Common.Data;
using Microsoft.AspNetCore.Http;
using Microsoft.EntityFrameworkCore;

namespace AcaMate.Common.Token;

public interface IHeaderConfig
{
    Task<string> GetExpectedHeaderValueAsync(string headerName);
}

/// <summary>
/// DB에서 헤더 키값 찾아서 그 밸류 값 빼오기 위해서 사용
/// </summary>
public class HeaderConfigRepository : IHeaderConfig
{
    private readonly AppDbContext _dbContext;

    public HeaderConfigRepository(AppDbContext dbContext)
    {
        _dbContext = dbContext;
    }

    public async Task<string> GetExpectedHeaderValueAsync(string headerName)
    {
        var config = await _dbContext.APIHeader
            .FirstOrDefaultAsync(h => h.h_key == headerName);
        return config?.h_value ?? string.Empty;
    }
    
}

public class APIHeaderMiddleware
{
    
    private readonly RequestDelegate _next;
    private readonly string[] _headerNames;
    // private readonly IHeaderConfig _headerConfig;

    public APIHeaderMiddleware(RequestDelegate next, string[] headerNames)//, IHeaderConfig headerConfig)
    {
        _next = next;
        _headerNames = headerNames;
    }

    public async Task Invoke(HttpContext context)
    {
        
        if (context.Request.Path.Equals("/api/v1/in/app", StringComparison.OrdinalIgnoreCase))
        {
            await _next(context);
            return;
        }
        
        // Scoped 사용해서 값 가져오는 곳임
        var headerConfig = context.RequestServices.GetRequiredService<IHeaderConfig>();
        
        bool valid = false;

        foreach (var header in _headerNames)
        {
            /// context.Request.Headers.TryGetValue(header, out var headerValue)
            /// header 를 찾는데 header
            if (context.Request.Headers.TryGetValue(header, out var headerValue) &&
                !string.IsNullOrWhiteSpace(headerValue))
            {
                var dbValue = await headerConfig.GetExpectedHeaderValueAsync(header);
                if (headerValue == dbValue)
                {
                    valid = true;
                    break;
                }
            }
        }

        if (!valid)
        {
            context.Response.StatusCode = StatusCodes.Status401Unauthorized;
            await context.Response.WriteAsync($"Invalid header value");
            return;
        }
        
        await _next(context);
    }
}