using System;
using System.IO;
using QRCoder;
using Furion.DependencyInjection;

namespace YD_Event.Core.Certificate
{
    /// <summary>
    /// 二维码服务
    /// </summary>
    public class QRCodeService : ITransient
    {
        /// <summary>
        /// 生成二维码图片
        /// </summary>
        /// <param name="content">二维码内容</param>
        /// <param name="size">二维码尺寸（像素）</param>
        /// <param name="logoPath">Logo图片路径（可选）</param>
        /// <returns>二维码图片流</returns>
        public Stream GenerateQRCode(string content, int size = 200, string logoPath = null)
        {
            using (var qrGenerator = new QRCodeGenerator())
            {
                var qrCodeData = qrGenerator.CreateQrCode(content, QRCodeGenerator.ECCLevel.M);
                
                // 使用PngByteQRCode来避免Bitmap依赖
                var qrCode = new PngByteQRCode(qrCodeData);
                var qrCodeBytes = qrCode.GetGraphic(
                    pixelsPerModule: CalculatePixelsPerModule(size));

                var outputStream = new MemoryStream(qrCodeBytes);
                outputStream.Position = 0;
                
                return outputStream;
            }
        }

        /// <summary>
        /// 生成证书二维码URL
        /// </summary>
        /// <param name="certificateId">证书ID</param>
        /// <param name="baseUrl">基础URL</param>
        /// <returns>证书查看URL</returns>
        public string GenerateCertificateUrl(long certificateId, string baseUrl)
        {
            if (string.IsNullOrWhiteSpace(baseUrl))
                throw new ArgumentException("Base URL cannot be null or empty", nameof(baseUrl));

            var normalizedBaseUrl = baseUrl.TrimEnd('/');
            return $"{normalizedBaseUrl}/certificate/view/{certificateId}";
        }

        /// <summary>
        /// 生成证书PDF下载URL
        /// </summary>
        /// <param name="certificateId">证书ID</param>
        /// <param name="pdfUrl">PDF文件URL</param>
        /// <returns>PDF下载URL</returns>
        public string GeneratePdfUrl(long certificateId, string pdfUrl)
        {
            if (string.IsNullOrWhiteSpace(pdfUrl))
                throw new ArgumentException("PDF URL cannot be null or empty", nameof(pdfUrl));

            return pdfUrl;
        }

        /// <summary>
        /// 生成带验证信息的二维码内容
        /// </summary>
        /// <param name="certificateId">证书ID</param>
        /// <param name="verificationCode">验证码</param>
        /// <param name="baseUrl">基础URL</param>
        /// <returns>验证URL</returns>
        public string GenerateVerificationUrl(long certificateId, string verificationCode, string baseUrl)
        {
            if (string.IsNullOrWhiteSpace(baseUrl))
                throw new ArgumentException("Base URL cannot be null or empty", nameof(baseUrl));

            if (string.IsNullOrWhiteSpace(verificationCode))
                throw new ArgumentException("Verification code cannot be null or empty", nameof(verificationCode));

            var normalizedBaseUrl = baseUrl.TrimEnd('/');
            return $"{normalizedBaseUrl}/certificate/verify/{certificateId}?code={verificationCode}";
        }

        /// <summary>
        /// 计算每个模块的像素数
        /// </summary>
        /// <param name="desiredSize">期望的二维码尺寸</param>
        /// <returns>每个模块的像素数</returns>
        private int CalculatePixelsPerModule(int desiredSize)
        {
            // 标准二维码是25x25或21x21模块，这里按25计算
            const int standardModules = 25;
            return Math.Max(1, desiredSize / standardModules);
        }

        /// <summary>
        /// 验证二维码内容
        /// </summary>
        /// <param name="content">二维码内容</param>
        /// <returns>是否有效</returns>
        public bool ValidateQRContent(string content)
        {
            if (string.IsNullOrWhiteSpace(content))
                return false;

            // 检查内容长度（二维码有容量限制）
            if (content.Length > 2953) // 数字模式的最大容量
                return false;

            // 检查是否为有效URL或文本
            return Uri.TryCreate(content, UriKind.Absolute, out _) || !content.Contains(" ");
        }

        /// <summary>
        /// 生成带样式的二维码
        /// </summary>
        /// <param name="content">二维码内容</param>
        /// <param name="options">二维码选项</param>
        /// <returns>二维码图片流</returns>
        public Stream GenerateStyledQRCode(string content, QRCodeOptions options)
        {
            using (var qrGenerator = new QRCodeGenerator())
            {
                var eccLevel = GetECCLevel(options.ErrorCorrectionLevel);
                var qrCodeData = qrGenerator.CreateQrCode(content, eccLevel);
                
                // 使用PngByteQRCode来避免Bitmap依赖
                var qrCode = new PngByteQRCode(qrCodeData);
                var pixelsPerModule = options.Size > 0 ? CalculatePixelsPerModule(options.Size) : 10;
                
                var qrCodeBytes = qrCode.GetGraphic(pixelsPerModule: pixelsPerModule);

                var outputStream = new MemoryStream(qrCodeBytes);
                outputStream.Position = 0;
                
                return outputStream;
            }
        }

        /// <summary>
        /// 获取错误纠正级别
        /// </summary>
        /// <param name="level">级别字符串</param>
        /// <returns>ECC级别</returns>
        private QRCodeGenerator.ECCLevel GetECCLevel(string level)
        {
            return level?.ToUpperInvariant() switch
            {
                "L" => QRCodeGenerator.ECCLevel.L,
                "M" => QRCodeGenerator.ECCLevel.M,
                "Q" => QRCodeGenerator.ECCLevel.Q,
                "H" => QRCodeGenerator.ECCLevel.H,
                _ => QRCodeGenerator.ECCLevel.M
            };
        }
    }

    /// <summary>
    /// 二维码选项
    /// </summary>
    public class QRCodeOptions
    {
        /// <summary>
        /// 二维码尺寸（像素）
        /// </summary>
        public int Size { get; set; } = 200;

        /// <summary>
        /// 深色（十六进制颜色代码）
        /// </summary>
        public string DarkColor { get; set; }

        /// <summary>
        /// 浅色（十六进制颜色代码）
        /// </summary>
        public string LightColor { get; set; }

        /// <summary>
        /// Logo图片路径
        /// </summary>
        public string LogoPath { get; set; }

        /// <summary>
        /// 错误纠正级别：L(7%), M(15%), Q(25%), H(30%)
        /// </summary>
        public string ErrorCorrectionLevel { get; set; } = "M";

        /// <summary>
        /// 是否绘制静区
        /// </summary>
        public bool DrawQuietZones { get; set; } = true;
    }
}