bitforum-backend/Application/Features/Member/Logs/Login/Search/Handler.cs

using SharedKernel.Extensions;
using Application.Abstractions.Data;
using MediatR;
using Microsoft.EntityFrameworkCore;

namespace Application.Features.Member.Logs.Login.Search;

public sealed class Handler(IAppDbContext db) : IRequestHandler<Query, Response>
{
    public async Task<Response> Handle(Query request, CancellationToken ct)
    {
        var query = db.MemberLoginLog.AsNoTracking().Include(x => x.Member).AsQueryable();

        if (!string.IsNullOrWhiteSpace(request.Keyword))
        {
            query = request.Search switch
            {
                1 => query.Where(x => x.MemberID.HasValue && x.MemberID.Value.ToString().Contains(request.Keyword)),
                2 => query.Where(x => x.Member != null && x.Member.Email.Contains(request.Keyword)),
                3 => query.Where(x => x.Member != null && x.Member.Name != null && x.Member.Name.Contains(request.Keyword)),
                _ => query
            };
        }

        if (!string.IsNullOrWhiteSpace(request.StartAt) && DateTime.TryParse(request.StartAt, out var startAt))
        {
            query = query.Where(x => x.CreatedAt >= startAt);
        }

        if (!string.IsNullOrWhiteSpace(request.EndAt) && DateTime.TryParse(request.EndAt, out var endAt))
        {
            query = query.Where(x => x.CreatedAt <= endAt);
        }

        var total = await query.CountAsync(ct);
        var skip = (request.PageNum - 1) * request.PerPage;

        var list = await query
            .OrderByDescending(x => x.ID)
            .Skip(skip)
            .Take(request.PerPage)
            .Select(x => new
            {
                x.ID,
                x.MemberID,
                MemberName = x.Member != null ? x.Member.Name : null,
                x.Account,
                x.Success,
                x.Reason,
                x.IpAddress,
                x.UserAgent,
                x.CreatedAt
            })
            .ToListAsync(ct);

        var rows = list.Select((x, idx) => new Response.Row
        {
            Num = total - skip - idx,
            ID = x.ID,
            MemberID = x.MemberID,
            MemberName = x.MemberName,
            Account = x.Account,
            Success = x.Success,
            Reason = x.Reason,
            IpAddress = x.IpAddress,
            UserAgent = x.UserAgent,
            Browser = ParseUserAgent(x.UserAgent, "browser"),
            OS = ParseUserAgent(x.UserAgent, "os"),
            Device = ParseUserAgent(x.UserAgent, "device"),
            CreatedAt = x.CreatedAt
        }).ToList();

        return new Response
        {
            Total = total,
            List = rows
        };
    }

    private static string? ParseUserAgent(string? userAgent, string type)
    {
        if (string.IsNullOrWhiteSpace(userAgent))
        {
            return null;
        }

        return type switch
        {
            "browser" => ExtractBrowser(userAgent),
            "os" => ExtractOS(userAgent),
            "device" => ExtractDevice(userAgent),
            _ => null
        };
    }

    private static string ExtractBrowser(string ua)
    {
        if (ua.Contains("Edg/")) return "Edge";
        if (ua.Contains("Chrome/")) return "Chrome";
        if (ua.Contains("Firefox/")) return "Firefox";
        if (ua.Contains("Safari/") && !ua.Contains("Chrome")) return "Safari";
        if (ua.Contains("MSIE") || ua.Contains("Trident/")) return "IE";
        return "Unknown";
    }

    private static string ExtractOS(string ua)
    {
        if (ua.Contains("Windows NT 10")) return "Windows 10";
        if (ua.Contains("Windows NT 6.3")) return "Windows 8.1";
        if (ua.Contains("Windows NT 6.1")) return "Windows 7";
        if (ua.Contains("Windows")) return "Windows";
        if (ua.Contains("Mac OS X")) return "macOS";
        if (ua.Contains("Android")) return "Android";
        if (ua.Contains("iPhone") || ua.Contains("iPad")) return "iOS";
        if (ua.Contains("Linux")) return "Linux";
        return "Unknown";
    }

    private static string ExtractDevice(string ua)
    {
        if (ua.Contains("Mobile") || ua.Contains("Android") && !ua.Contains("Tablet")) return "Mobile";
        if (ua.Contains("Tablet") || ua.Contains("iPad")) return "Tablet";
        return "Desktop";
    }
}