using System;
using System.Collections.Generic;
using System.Linq;
using QuestPDF.Fluent;
using QuestPDF.Helpers;
using QuestPDF.Infrastructure;
using YD_Event.Core.Entities;
using System.Text.Json;

namespace YD_Event.Core.Certificate
{
    /// <summary>
    /// 动态证书生成文档
    /// </summary>
    public class CertificateDocument : IDocument
    {
        private readonly Entities.Certificate _certificate;
        private readonly Dictionary<string, object> _data;
        private readonly byte[] _templateBytes;

        public CertificateDocument(Entities.Certificate certificate, Dictionary<string, object> data, byte[] templateBytes)
        {
            _certificate = certificate;
            _data = data;
            _templateBytes = templateBytes;
        }

        public DocumentMetadata GetMetadata() => DocumentMetadata.Default;

        public void Compose(IDocumentContainer container)
        {
            container.Page(page =>
            {
                // 设置页面大小
                page.Size(new PageSize((float)_certificate.Width, (float)_certificate.Height));
                page.Margin(0); // 无边距，背景铺满
                page.DefaultTextStyle(x => x.FontFamily("Source Han Sans CN")); // 默认字体

                // 设置背景
                page.Background().Image(_templateBytes);

                // 内容层
                page.Content().Layers(layers =>
                {
                    // 解析占位符配置
                    var placeholders = string.IsNullOrEmpty(_certificate.Placeholders) 
                        ? new List<CertificatePlaceholder>() 
                        : JsonSerializer.Deserialize<List<CertificatePlaceholder>>(_certificate.Placeholders);

                    foreach (var p in placeholders)
                    {
                        // 获取数据对象
                        var dataObj = _data.ContainsKey(p.Key) ? _data[p.Key] : null;
                        if (dataObj == null) continue;

                        // 定位层
                        layers.Layer()
                            .TranslateX(p.X)
                            .TranslateY(p.Y)
                            .Width(p.Width)
                            .Height(p.Height)
                            .Element(element =>
                            {
                                if (p.Type == "Image")
                                {
                                    if (dataObj is byte[] imgBytes)
                                    {
                                        element.Image(imgBytes);
                                    }
                                    else if (dataObj is string url && !string.IsNullOrEmpty(url))
                                    {
                                        // 暂不支持直接URL渲染，需预先下载转为byte[]
                                        element.Border(1).BorderColor(Colors.Red.Medium).AlignCenter().AlignMiddle().Text($"Image: {p.Key}");
                                    }
                                }
                                else if (p.Type == "QRCode")
                                {
                                    // 暂无二维码生成库，显示占位符
                                    // 实际项目建议引入 QRCoder 或类似库生成 byte[] 后渲染
                                    element.Border(1).BorderColor(Colors.Black).AlignCenter().AlignMiddle().Text("QR Code");
                                }
                                else
                                {
                                    // 文本处理
                                    string value = dataObj.ToString();
                                    
                                    // 处理日期格式化
                                    if (!string.IsNullOrEmpty(p.FormatString))
                                    {
                                        if (dataObj is DateTime dt)
                                        {
                                            value = dt.ToString(p.FormatString);
                                        }
                                        else if (DateTime.TryParse(value, out var dtParsed))
                                        {
                                            value = dtParsed.ToString(p.FormatString);
                                        }
                                    }
                                    
                                    var text = element.Text(value);
                                    
                                    // 样式设置
                                    var style = TextStyle.Default.FontSize(p.FontSize > 0 ? p.FontSize : 12);
                                    if (!string.IsNullOrEmpty(p.FontFamily)) style = style.FontFamily(p.FontFamily);
                                    if (!string.IsNullOrEmpty(p.Color)) style = style.FontColor(p.Color);
                                    
                                    text.Style(style);
                                    
                                    // 对齐方式
                                    if (p.TextAlign == "Center") element.AlignCenter();
                                    else if (p.TextAlign == "Right") element.AlignRight();
                                    else element.AlignLeft();
                                }
                            });
                    }
                });
            });
        }
    }
}