using Fake.Application;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;

namespace Oms.Application.Shared;

/// <summary>
/// OMS 上传文件落盘（wwwroot/uploads）。
/// </summary>
public static class OmsFileUploadHelper
{
    private static readonly HashSet<string> ImageExtensions =
        new(StringComparer.OrdinalIgnoreCase) { ".jpg", ".jpeg", ".png", ".webp", ".gif", ".bmp" };

    private const long MaxImageBytes = 5 * 1024 * 1024;

    /// <summary>
    /// 保存充值截图，返回以 /uploads 开头的相对访问路径。
    /// </summary>
    public static Task<string> SaveRechargeScreenshotAsync(IFormFile? file, IWebHostEnvironment env) =>
        SaveImageAsync(file, env, "recharge", "充值截图");

    /// <summary>
    /// 保存仓储 SKU 图片。
    /// </summary>
    public static Task<string> SaveWarehouseSkuImageAsync(IFormFile file, IWebHostEnvironment env) =>
        SaveImageAsync(file, env, "sku", "SKU 图片");

    /// <summary>
    /// 保存包裹商品图片。
    /// </summary>
    public static Task<string> SaveWarehouseParcelImageAsync(IFormFile file, IWebHostEnvironment env) =>
        SaveImageAsync(file, env, "parcel", "包裹商品图片");

    private static async Task<string> SaveImageAsync(
        IFormFile? file,
        IWebHostEnvironment env,
        string folder,
        string label)
    {
        if (file == null || file.Length <= 0)
        {
            if (folder == "recharge")
            {
                return "0";
            }

            throw new BusinessException($"{label}不能为空");
        }

        if (file.Length > MaxImageBytes)
        {
            throw new BusinessException($"{label}大小不能超过 5MB");
        }

        var ext = Path.GetExtension(file.FileName);
        if (string.IsNullOrWhiteSpace(ext) || !ImageExtensions.Contains(ext))
        {
            ext = GuessExtensionFromContentType(file.ContentType) ?? ".jpg";
        }

        if (!ImageExtensions.Contains(ext))
        {
            throw new BusinessException($"{label}仅支持 jpg、png、webp、gif、bmp 格式");
        }

        var webRoot = env.WebRootPath;
        if (string.IsNullOrWhiteSpace(webRoot))
        {
            webRoot = Path.Combine(env.ContentRootPath, "wwwroot");
        }

        var monthFolder = DateTime.Now.ToString("yyyyMM");
        var relativeDir = Path.Combine("uploads", folder, monthFolder);
        var absoluteDir = Path.Combine(webRoot, relativeDir);
        Directory.CreateDirectory(absoluteDir);

        var fileName = $"{Guid.NewGuid():N}{ext.ToLowerInvariant()}";
        var absolutePath = Path.Combine(absoluteDir, fileName);
        await using (var stream = File.Create(absolutePath))
        {
            await file.CopyToAsync(stream);
        }

        return $"/uploads/{folder}/{monthFolder}/{fileName}".Replace('\\', '/');
    }

    private static readonly HashSet<string> ExcelExtensions =
        new(StringComparer.OrdinalIgnoreCase) { ".xlsx", ".xls" };

    private const long MaxOrderTemplateBytes = 10 * 1024 * 1024;

    /// <summary>
    /// 保存下单自定义模板样例文件。
    /// </summary>
    public static async Task<(string RelativePath, string FileName)> SaveOrderTemplateSampleAsync(
        IFormFile file,
        int customerId,
        IWebHostEnvironment env)
    {
        if (file == null || file.Length <= 0)
        {
            throw new BusinessException("上传文件不能为空");
        }

        if (file.Length > MaxOrderTemplateBytes)
        {
            throw new BusinessException("模板文件大小不能超过 10MB");
        }

        var ext = Path.GetExtension(file.FileName);
        if (string.IsNullOrWhiteSpace(ext) || !ExcelExtensions.Contains(ext))
        {
            throw new BusinessException("仅支持 .xlsx / .xls 文件");
        }

        var webRoot = env.WebRootPath;
        if (string.IsNullOrWhiteSpace(webRoot))
        {
            webRoot = Path.Combine(env.ContentRootPath, "wwwroot");
        }

        var relativeDir = Path.Combine("uploads", "order-templates", customerId.ToString());
        var absoluteDir = Path.Combine(webRoot, relativeDir);
        Directory.CreateDirectory(absoluteDir);

        var fileName = $"{Guid.NewGuid():N}{ext.ToLowerInvariant()}";
        var absolutePath = Path.Combine(absoluteDir, fileName);
        await using (var stream = File.Create(absolutePath))
        {
            await file.CopyToAsync(stream);
        }

        var relativePath = $"/uploads/order-templates/{customerId}/{fileName}".Replace('\\', '/');
        return (relativePath, Path.GetFileName(file.FileName));
    }

    public static string ResolveWebRootAbsolutePath(IWebHostEnvironment env, string relativePath)
    {
        var webRoot = env.WebRootPath;
        if (string.IsNullOrWhiteSpace(webRoot))
        {
            webRoot = Path.Combine(env.ContentRootPath, "wwwroot");
        }

        var trimmed = relativePath.TrimStart('/').Replace('/', Path.DirectorySeparatorChar);
        return Path.Combine(webRoot, trimmed);
    }

    private static string? GuessExtensionFromContentType(string? contentType) => contentType?.ToLowerInvariant() switch
    {
        "image/jpeg" or "image/jpg" => ".jpg",
        "image/png" => ".png",
        "image/webp" => ".webp",
        "image/gif" => ".gif",
        "image/bmp" => ".bmp",
        _ => null
    };
}