using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;

namespace SlideCombine
{
    /// <summary>
    /// Bkmk文件智能排序比较器
    /// 按文件夹名称中的数字部分进行排序
    /// </summary>
    public class BkmkFileComparer : IComparer<string>
    {
        public int Compare(string x, string y)
        {
            if (x == null && y == null) return 0;
            if (x == null) return -1;
            if (y == null) return 1;

            // 获取文件夹名称（去掉路径和文件名）
            var xFolder = Path.GetFileName(Path.GetDirectoryName(x));
            var yFolder = Path.GetFileName(Path.GetDirectoryName(y));

            // 提取数字部分进行智能排序
            var xNumber = ExtractNumberFromFolder(xFolder);
            var yNumber = ExtractNumberFromFolder(yFolder);

            // 如果都有数字，按数字大小排序
            if (xNumber.HasValue && yNumber.HasValue)
            {
                int result = xNumber.Value.CompareTo(yNumber.Value);
                if (result != 0) return result;
            }
            // 如果只有一方有数字，有数字的排前面
            else if (xNumber.HasValue)
            {
                return -1;
            }
            else if (yNumber.HasValue)
            {
                return 1;
            }

            // 如果都没有数字或数字相同，按完整字符串排序
            return string.Compare(x, y, StringComparison.OrdinalIgnoreCase);
        }

        private int? ExtractNumberFromFolder(string folderName)
        {
            // 使用正则表达式提取文件夹名称中的数字部分
            // 支持格式：CH-875 1-3, CH-875 4-6, CH-875 10-12, Volume 2, Part 1等
            var match = Regex.Match(folderName, @"(?:[\w-]+\s+)?(\d+)", RegexOptions.IgnoreCase);

            if (match.Success && match.Groups.Count > 1)
            {
                string numberStr = match.Groups[1].Value;
                if (int.TryParse(numberStr, out int number))
                {
                    return number;
                }
            }

            return null;
        }
    }
    public class ProcessResult
    {
        public string BaseFileName { get; set; }
        public List<string> SourceFiles { get; set; }
        public string OutputContent { get; set; }
        public bool Success { get; set; }
        public string ErrorMessage { get; set; }
        public List<DocumentMetadata> MetadataDocuments { get; set; }
    }

    public class FileMerger
    {
        public static List<ProcessResult> ProcessAllFolders(string pdfRootPath, string txtSourcePath, string txtOutputPath)
        {
            var results = new List<ProcessResult>();

            try
            {
                // 获取所有包含FreePic2Pdf_bkmk文件的文件夹（支持无扩展名和.txt扩展名）
                var bkmkFiles = new List<string>();
                bkmkFiles.AddRange(Directory.GetFiles(pdfRootPath, "FreePic2Pdf_bkmk", SearchOption.AllDirectories));
                bkmkFiles.AddRange(Directory.GetFiles(pdfRootPath, "FreePic2Pdf_bkmk.txt", SearchOption.AllDirectories));

                if (bkmkFiles.Count == 0)
                {
                    throw new Exception($"在路径 {pdfRootPath} 下未找到任何 FreePic2Pdf_bkmk 或 FreePic2Pdf_bkmk.txt 文件");
                }

                // 检查TXT源路径是否存在
                if (!Directory.Exists(txtSourcePath))
                {
                    throw new Exception($"TXT源文件路径不存在: {txtSourcePath}");
                }

                // 按基础文件名分组（取文件夹名称的空格前缀）
                var fileGroups = new Dictionary<string, List<string>>();

                foreach (var bkmkFile in bkmkFiles)
                {
                    var folderName = Path.GetDirectoryName(bkmkFile);
                    var folderNameOnly = new DirectoryInfo(folderName).Name;

                    // 获取空格前的基础名称
                    var baseName = GetBaseFileName(folderNameOnly);

                    if (!fileGroups.ContainsKey(baseName))
                    {
                        fileGroups[baseName] = new List<string>();
                    }

                    fileGroups[baseName].Add(bkmkFile);
                }

                // 处理每个分组
                foreach (var group in fileGroups)
                {
                    var result = ProcessFileGroup(group.Key, group.Value.OrderBy(f => f, new BkmkFileComparer()).ToList(), txtSourcePath);
                    results.Add(result);
                }
            }
            catch (Exception ex)
            {
                var errorResult = new ProcessResult
                {
                    Success = false,
                    ErrorMessage = ex.Message
                };
                results.Add(errorResult);
            }

            return results;
        }

        private static string GetBaseFileName(string folderName)
        {
            // 获取空格前的部分作为基础名称
            var spaceIndex = folderName.IndexOf(' ');
            return spaceIndex > 0 ? folderName.Substring(0, spaceIndex) : folderName;
        }

        private static ProcessResult ProcessFileGroup(string baseName, List<string> bkmkFiles, string txtSourcePath)
        {
            var result = new ProcessResult
            {
                BaseFileName = baseName,
                SourceFiles = bkmkFiles,
                Success = true,
                MetadataDocuments = new List<DocumentMetadata>()
            };

            try
            {
                foreach (var bkmkFile in bkmkFiles)
                {
                    // 获取对应的TXT文件路径
                    var txtFile = GetCorrespondingTxtFile(bkmkFile, txtSourcePath);

                    // 创建元数据文档
                    var metadata = CreateMetadataFromFiles(txtFile, bkmkFile);

                    if (metadata != null)
                    {
                        result.MetadataDocuments.Add(metadata);
                    }
                }

                // 合并所有元数据文档
                var combinedContent = ContentFormatter.CombineFormattedMetadataDocuments(result.MetadataDocuments);
                result.OutputContent = combinedContent;
            }
            catch (Exception ex)
            {
                result.Success = false;
                result.ErrorMessage = $"处理文件组 {baseName} 时出错: {ex.Message}";
            }

            return result;
        }

        private static string GetCorrespondingTxtFile(string bkmkFile, string txtSourcePath)
        {
            var directory = Path.GetDirectoryName(bkmkFile);
            var folderName = new DirectoryInfo(directory).Name;

            // 在指定的TXT源路径中查找对应的文件
            var txtFile = Path.Combine(txtSourcePath, $"{folderName}.txt");

            return File.Exists(txtFile) ? txtFile : null;
        }

        private static DocumentMetadata CreateMetadataFromFiles(string txtFile, string bkmkFile)
        {
            var metadata = new DocumentMetadata();

            if (File.Exists(txtFile))
            {
                // 从TXT文件读取元数据
                ReadMetadataFromTxt(txtFile, metadata);
            }

            // 从bkmk文件提取书签
            if (File.Exists(bkmkFile))
            {
                metadata.TableOfContents = BookmarkExtractor.ExtractBookmarksFromBkmk(bkmkFile);
            }

            return metadata;
        }

        private static void ReadMetadataFromTxt(string txtFile, DocumentMetadata metadata)
        {
            try
            {
                string[] lines;
                // 在Windows上使用GB2312编码读取，正确处理中文字符
                try
                {
                    lines = File.ReadAllLines(txtFile, Encoding.GetEncoding("GB2312"));
                }
                catch
                {
                    // 如果GB2312不可用，使用系统默认编码
                    lines = File.ReadAllLines(txtFile, Encoding.Default);
                }

                foreach (var line in lines)
                {
                    var parts = line.Split(new[] { ':' }, 2);
                    if (parts.Length == 2)
                    {
                        var key = parts[0].Trim();
                        var value = parts[1].Trim();

                        switch (key)
                        {
                            case "title":
                                metadata.Title = value;
                                break;
                            case "Other titles":
                                metadata.OtherTitles = value;
                                break;
                            case "Volume":
                                metadata.Volume = value;
                                break;
                            case "ISBN":
                                metadata.ISBN = value;
                                break;
                            case "creator":
                                metadata.Creator = value;
                                break;
                            case "contributor":
                                metadata.Contributor = value;
                                break;
                            case "issuedDate":
                                metadata.IssuedDate = value;
                                break;
                            case "publisher":
                                metadata.Publisher = value;
                                break;
                            case "place":
                                metadata.Place = value;
                                break;
                            case "Classification number":
                                metadata.ClassificationNumber = value;
                                break;
                            case "page":
                                metadata.Page = value;
                                break;
                            case "subject":
                                metadata.Subject = value;
                                break;
                            case "date":
                                metadata.Date = value;
                                break;
                            case "spatial":
                                metadata.Spatial = value;
                                break;
                            case "Other ISBN":
                                metadata.OtherISBN = value;
                                break;
                            case "Other time":
                                metadata.OtherTime = value;
                                break;
                            case "url":
                                metadata.Url = value;
                                break;
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                throw new Exception($"读取TXT文件 {txtFile} 失败: {ex.Message}");
            }
        }

        public static void SaveResults(List<ProcessResult> results, string outputPath)
        {
            if (!Directory.Exists(outputPath))
            {
                Directory.CreateDirectory(outputPath);
            }

            foreach (var result in results)
            {
                if (result.Success && !string.IsNullOrEmpty(result.OutputContent))
                {
                    var outputFileName = $"{result.BaseFileName}.txt";
                    var outputFilePath = Path.Combine(outputPath, outputFileName);

                    // 使用UTF-8 with BOM保存，支持特殊字符
                    var utf8WithBom = new UTF8Encoding(true);
                    File.WriteAllText(outputFilePath, result.OutputContent, utf8WithBom);
                }
            }
        }
    }
}