using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Wordprocessing;
using DocumentFormat.OpenXml.Drawing.Wordprocessing;
using Furion.DependencyInjection;

namespace YD_Event.Core.Certificate
{
    /// <summary>
    /// DOCX模板处理器
    /// </summary>
    public class DocxTemplateProcessor : ITransient
    {
        private const string PlaceholderPattern = @"\{\{([^}]+)\}\}";

        /// <summary>
        /// 处理DOCX模板，替换占位符
        /// </summary>
        /// <param name="templateStream">模板文件流</param>
        /// <param name="data">数据字典</param>
        /// <param name="qrCodeData">二维码数据字典</param>
        /// <returns>处理后的文件流</returns>
        public Stream ProcessTemplate(Stream templateStream, Dictionary<string, string> data, Dictionary<string, string> qrCodeData = null)
        {
            var outputStream = new MemoryStream();
            
            // 复制模板到输出流
            templateStream.Position = 0;
            templateStream.CopyTo(outputStream);
            outputStream.Position = 0;

            using (var document = WordprocessingDocument.Open(outputStream, true))
            {
                var body = document.MainDocumentPart?.Document?.Body;
                if (body == null) return outputStream;

                // 处理段落中的占位符
                ProcessParagraphs(body, data, qrCodeData);

                // 处理表格中的占位符
                ProcessTables(body, data, qrCodeData);

                // 处理页眉页脚中的占位符
                ProcessHeaderFooter(document, data, qrCodeData);

                document.Save();
            }

            outputStream.Position = 0;
            return outputStream;
        }

        /// <summary>
        /// 处理段落中的占位符
        /// </summary>
        private void ProcessParagraphs(Body body, Dictionary<string, string> data, Dictionary<string, string> qrCodeData)
        {
            foreach (var paragraph in body.Elements<Paragraph>())
            {
                ProcessParagraph(paragraph, data, qrCodeData);
            }
        }

        /// <summary>
        /// 处理单个段落
        /// </summary>
        private void ProcessParagraph(Paragraph paragraph, Dictionary<string, string> data, Dictionary<string, string> qrCodeData)
        {
            var runs = paragraph.Elements<Run>().ToList();
            
            foreach (var run in runs)
            {
                var texts = run.Elements<Text>().ToList();
                foreach (var text in texts)
                {
                    var processedText = ReplacePlaceholders(text.Text, data, qrCodeData);
                    
                    // 检查是否是二维码占位符
                    if (IsQRCodePlaceholder(text.Text))
                    {
                        var placeholder = ExtractPlaceholderKey(text.Text);
                        if (qrCodeData != null && qrCodeData.ContainsKey(placeholder))
                        {
                            // 替换为二维码图片
                            ReplaceTextWithQRCode(run, qrCodeData[placeholder]);
                        }
                        else
                        {
                            text.Text = processedText;
                        }
                    }
                    else
                    {
                        text.Text = processedText;
                    }
                }
            }
        }

        /// <summary>
        /// 处理表格中的占位符
        /// </summary>
        private void ProcessTables(Body body, Dictionary<string, string> data, Dictionary<string, string> qrCodeData)
        {
            foreach (var table in body.Elements<Table>())
            {
                foreach (var row in table.Elements<TableRow>())
                {
                    foreach (var cell in row.Elements<TableCell>())
                    {
                        foreach (var paragraph in cell.Elements<Paragraph>())
                        {
                            ProcessParagraph(paragraph, data, qrCodeData);
                        }
                    }
                }
            }
        }

        /// <summary>
        /// 处理页眉页脚中的占位符
        /// </summary>
        private void ProcessHeaderFooter(WordprocessingDocument document, 
            Dictionary<string, string> data, Dictionary<string, string> qrCodeData)
        {
            // 暂时跳过页眉页脚处理，因为API兼容性问题
            // 实际项目中需要根据具体的DocumentFormat.OpenXml版本调整
        }

        /// <summary>
        /// 替换文本中的占位符
        /// </summary>
        private string ReplacePlaceholders(string text, Dictionary<string, string> data, Dictionary<string, string> qrCodeData)
        {
            if (string.IsNullOrWhiteSpace(text)) return text;

            return Regex.Replace(text, PlaceholderPattern, match =>
            {
                var key = match.Groups[1].Value.Trim();
                
                // 优先使用二维码数据
                if (qrCodeData != null && qrCodeData.ContainsKey(key))
                {
                    return qrCodeData[key];
                }
                
                // 使用普通数据
                if (data != null && data.ContainsKey(key))
                {
                    return data[key] ?? string.Empty;
                }
                
                // 返回原始占位符（未找到数据）
                return match.Value;
            });
        }

        /// <summary>
        /// 检查是否是二维码占位符
        /// </summary>
        private bool IsQRCodePlaceholder(string text)
        {
            if (string.IsNullOrWhiteSpace(text)) return false;
            
            var match = Regex.Match(text, PlaceholderPattern);
            if (!match.Success) return false;
            
            var key = match.Groups[1].Value.Trim().ToLowerInvariant();
            return key.Contains("qr") || key.Contains("qrcode");
        }

        /// <summary>
        /// 提取占位符键名
        /// </summary>
        private string ExtractPlaceholderKey(string text)
        {
            var match = Regex.Match(text, PlaceholderPattern);
            return match.Success ? match.Groups[1].Value.Trim() : string.Empty;
        }

        /// <summary>
        /// 将文本替换为二维码图片
        /// </summary>
        private void ReplaceTextWithQRCode(Run run, string qrCodeContent)
        {
            // 注意：这里需要实现二维码图片生成和插入逻辑
            // 由于DocumentFormat.OpenXml处理图片比较复杂，这里先简化处理
            // 实际实现需要使用QRCodeService生成图片，然后插入到文档中
            
            // 临时实现：用文本替代
            var texts = run.Elements<Text>().ToList();
            foreach (var text in texts)
            {
                text.Text = $"[QR: {qrCodeContent}]";
            }
        }

        /// <summary>
        /// 验证数据完整性
        /// </summary>
        /// <param name="requiredPlaceholders">必填占位符列表</param>
        /// <param name="data">数据字典</param>
        /// <returns>验证结果</returns>
        public TemplateValidationResult ValidateTemplateData(List<string> requiredPlaceholders, Dictionary<string, string> data)
        {
            var result = new TemplateValidationResult { IsValid = true };
            
            foreach (var placeholder in requiredPlaceholders)
            {
                if (!data.ContainsKey(placeholder) || string.IsNullOrWhiteSpace(data[placeholder]))
                {
                    result.IsValid = false;
                    result.MissingPlaceholders.Add(placeholder);
                }
            }
            
            return result;
        }
    }

    /// <summary>
    /// 模板验证结果
    /// </summary>
    public class TemplateValidationResult
    {
        public bool IsValid { get; set; }
        public List<string> MissingPlaceholders { get; set; } = new List<string>();
        public List<string> Warnings { get; set; } = new List<string>();
    }
}