using Domain.Entities.Store.ValueObject;
using SharedKernel.Attributes;
using SharedKernel.Extensions;
using SharedKernel.Helpers;
using Application.Abstractions.Messaging;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;

namespace Admin.Pages.Store.Coupon;

public class CodesModel(IMediator mediator) : PageModel
{
    [BindProperty(SupportsGet = true)]
    public int ID { get; set; }

    [BindProperty(SupportsGet = true)]
    public QueryParams Query { get; set; } = new();

    public string CouponName { get; private set; } = "";
    public string GameName { get; private set; } = "";
    public string ProductName { get; private set; } = "";

    public int Total { get; set; }
    public int AvailableCount { get; set; }
    public int ReservedCount { get; set; }
    public int IssuedCount { get; set; }
    public int UsedCount { get; set; }
    public int ExpiredCount { get; set; }

    public sealed class QueryParams
    {
        [Range(1, int.MaxValue)]
        public int PageNum { get; set; } = 1;

        [Range(1, 200)]
        public ushort PerPage { get; set; } = 50;

        [DisplayName("코드 상태")]
        public CouponCodeStatus? Status { get; set; }
    }

    public List<(
        int Num,
        int ID,
        string Code,
        string StatusText,
        int? IssuedToMemberID,
        string? IssuedToMemberName,
        string? IssuedToMemberEmail,
        string? IssuedAt,
        string? UsedAt,
        string CreatedAt
    )> List { get; set; } = [];

    public Pagination? Pagination { get; set; }

    [BindProperty]
    public UploadInput Upload { get; set; } = new();

    public sealed class UploadInput
    {
        [DisplayName("CSV 파일")]
        [Required(ErrorMessage = "{0}을(를) 선택하세요.")]
        [AllowedExtensions("csv,txt", ErrorMessage = "CSV 또는 TXT 파일만 허용됩니다.")]
        public IFormFile? CsvFile { get; set; }
    }

    public async Task OnGetAsync(CancellationToken ct)
    {
        if (!ModelState.IsValid)
        {
            return;
        }

        await LoadHeaderAsync(ct);
        await LoadListAsync(ct);
    }

    public async Task<IActionResult> OnPostUploadAsync(CancellationToken ct)
    {
        if (!ModelState.IsValid)
        {
            TempData["ErrorMessages"] = ModelState.GetErrorMessages();
            return RedirectToPage("/Store/Coupon/Codes", new { id = ID });
        }

        var result = await mediator.Send(new ImportCouponCodes.Command(ID, Upload.CsvFile!), ct);

        if (result.IsFailure)
        {
            TempData["ErrorMessages"] = result.Error.Description;
        }
        else
        {
            var r = result.Value;
            TempData["SuccessMessage"] =
                $"CSV 업로드 완료. 총 {r.TotalLines}줄 / 추가 {r.Added}개 (미사용 {r.AddedAvailable} + 사용됨 {r.AddedUsed}) / 중복 skip {r.SkippedDuplicate}개 / 회원미존재 skip {r.SkippedMissingMember}개 / 무효 skip {r.SkippedInvalid}개.";
        }

        return RedirectToPage("/Store/Coupon/Codes", new { id = ID });
    }

    public async Task<IActionResult> OnGetExportAsync(int id, CancellationToken ct)
    {
        var result = await mediator.Send(new ExportCouponCodes.Query(id), ct);

        if (result.IsFailure)
        {
            TempData["ErrorMessages"] = result.Error.Description;
            return RedirectToPage("/Store/Coupon/Codes", new { id });
        }

        var data = result.Value;
        return File(data.CsvBytes, "text/csv; charset=utf-8", data.FileName);
    }

    public async Task<IActionResult> OnPostDeleteCodesAsync(int id, int[] codeIDs, CancellationToken ct)
    {
        if (codeIDs is null || codeIDs.Length == 0)
        {
            TempData["ErrorMessages"] = "삭제할 코드를 선택해 주세요.";
            return RedirectToPage("/Store/Coupon/Codes", new { id });
        }

        var result = await mediator.Send(new DeleteCouponCodes.Command(id, codeIDs), ct);

        if (result.IsFailure)
        {
            TempData["ErrorMessages"] = result.Error.Description;
        }
        else
        {
            TempData["SuccessMessage"] = $"{result.Value.Deleted}개 코드가 삭제되었습니다.";
        }

        return RedirectToPage("/Store/Coupon/Codes", new { id });
    }

    public async Task<IActionResult> OnPostExpireCodesAsync(int id, int[] codeIDs, CancellationToken ct)
    {
        if (codeIDs is null || codeIDs.Length == 0)
        {
            TempData["ErrorMessages"] = "만료 처리할 코드를 선택해 주세요.";
            return RedirectToPage("/Store/Coupon/Codes", new { id });
        }

        var result = await mediator.Send(new ExpireCouponCodes.Command(id, codeIDs), ct);

        if (result.IsFailure)
        {
            TempData["ErrorMessages"] = result.Error.Description;
        }
        else
        {
            TempData["SuccessMessage"] = $"{result.Value.Expired}개 코드가 만료 처리되었습니다.";
        }

        return RedirectToPage("/Store/Coupon/Codes", new { id });
    }

    public async Task<IActionResult> OnPostRestoreCodesAsync(int id, int[] codeIDs, CancellationToken ct)
    {
        if (codeIDs is null || codeIDs.Length == 0)
        {
            TempData["ErrorMessages"] = "복귀 처리할 코드를 선택해 주세요.";
            return RedirectToPage("/Store/Coupon/Codes", new { id });
        }

        var result = await mediator.Send(new RestoreCouponCodes.Command(id, codeIDs), ct);

        if (result.IsFailure)
        {
            TempData["ErrorMessages"] = result.Error.Description;
        }
        else
        {
            TempData["SuccessMessage"] = $"{result.Value.Restored}개 코드가 복귀 처리되었습니다.";
        }

        return RedirectToPage("/Store/Coupon/Codes", new { id });
    }

    public IActionResult OnGetTemplate()
    {
        // 헤더만 담긴 빈 양식
        var header = new[]
        {
            "ID",
            "Code",
            "Status",
            "IssuedToMemberID",
            "IssuedToMemberName",
            "IssuedToMemberEmail",
            "IssuedAt",
            "UsedAt",
            "CreatedAt"
        };

        var bytes = SharedKernel.Helpers.CsvHelper.WriteUtf8Bom([header]);
        return File(bytes, "text/csv; charset=utf-8", "coupon-codes-template.csv");
    }

    private async Task LoadHeaderAsync(CancellationToken ct)
    {
        var head = await mediator.Send(new GetCoupon.Query(ID), ct);

        if (head.IsFailure)
        {
            TempData["ErrorMessages"] = head.Error.Description;
            return;
        }

        CouponName = head.Value.Name;
        GameName = head.Value.GameName;
        ProductName = head.Value.ProductName;
    }

    private async Task LoadListAsync(CancellationToken ct)
    {
        var result = await mediator.Send(new ListCouponCodes.Query(ID, Query.Status, Query.PageNum, Query.PerPage), ct);

        Total = result.Total;
        AvailableCount = result.AvailableCount;
        ReservedCount = result.ReservedCount;
        IssuedCount = result.IssuedCount;
        UsedCount = result.UsedCount;
        ExpiredCount = result.ExpiredCount;

        List = [.. result.List.Select(c => (
            c.Num,
            c.ID,
            c.Code,
            StatusText: c.Status switch
            {
                CouponCodeStatus.Available => "사용 가능",
                CouponCodeStatus.Reserved => "결제 진행 중",
                CouponCodeStatus.Issued => "발급됨",
                CouponCodeStatus.Used => "사용됨",
                CouponCodeStatus.Expired => "만료",
                _ => "?"
            },
            c.IssuedToMemberID,
            c.IssuedToMemberName,
            c.IssuedToMemberEmail,
            c.IssuedAt?.ToString("yyyy-MM-dd HH:mm"),
            c.UsedAt?.ToString("yyyy-MM-dd HH:mm"),
            c.CreatedAt.GetDateAt()
        ))];

        Pagination = new Pagination(result.Total, Query.PageNum, Query.PerPage);
    }
}