using Aspose.Words;
using Aspose.Words.Tables;
using Aspose.Words.Fields;
using System.Text;

namespace OASystem.API.OAMethodLib.FileProcessing
{
    /// <summary>
    /// 文件处理服务，使用Aspose.Words处理Word文档
    /// </summary>
    public class FileProcessingService : IFileProcessingService
    {
        private readonly ILogger<FileProcessingService> _logger;
        private readonly IConfiguration _configuration;

        public FileProcessingService(
            ILogger<FileProcessingService> logger,
            IConfiguration configuration)
        {
            _logger = logger;
            _configuration = configuration;
            InitializeAsposeLicense();
        }

        /// <summary>
        /// 初始化Aspose.Words许可证
        /// </summary>
        private void InitializeAsposeLicense()
        {
            try
            {
                var licensePath = _configuration["Aspose:LicensePath"];
                if (!string.IsNullOrEmpty(licensePath) && System.IO.File.Exists(licensePath))
                {
                    var license = new License();
                    license.SetLicense(licensePath);
                    _logger.LogInformation("Aspose.Words 15.12.0 许可证已成功加载");
                }
                else
                {
                    _logger.LogWarning("Aspose.Words许可证文件未找到，将使用评估模式");
                }
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Aspose.Words许可证初始化失败");
            }
        }

        /// <summary>
        /// 处理Word文档并提取结构化信息
        /// </summary>
        public async Task<ProcessingResult> ProcessWordDocumentAsync(IFormFile file)
        {
            var stopwatch = System.Diagnostics.Stopwatch.StartNew();

            try
            {
                _logger.LogInformation("开始处理Word文档: {FileName} ({Size} bytes)",
                    file.FileName, file.Length);

                if (!IsSupportedWordFormat(file.FileName))
                {
                    return new ProcessingResult
                    {
                        Success = false,
                        ErrorMessage = $"不支持的文件格式: {Path.GetExtension(file.FileName)}",
                        FileSize = file.Length,
                        FileType = file.ContentType
                    };
                }

                using var stream = new MemoryStream();
                await file.CopyToAsync(stream);
                stream.Position = 0;

                var documentInfo = await ExtractDocumentInfoAsync(stream, file.FileName);

                stopwatch.Stop();

                _logger.LogInformation("Word文档处理完成: {FileName}, 耗时: {ElapsedMs}ms",
                    file.FileName, stopwatch.ElapsedMilliseconds);

                return new ProcessingResult
                {
                    Success = true,
                    Data = documentInfo,
                    FileSize = file.Length,
                    FileType = file.ContentType
                };
            }
            catch (Exception ex)
            {
                stopwatch.Stop();
                _logger.LogError(ex, "Word文档处理失败: {FileName}", file.FileName);

                return new ProcessingResult
                {
                    Success = false,
                    ErrorMessage = $"处理失败: {ex.Message}",
                    FileSize = file.Length,
                    FileType = file.ContentType
                };
            }
        }

        /// <summary>
        /// 批量处理Word文档
        /// </summary>
        public async Task<List<ProcessingResult>> ProcessWordDocumentsAsync(List<IFormFile> files)
        {
            var results = new List<ProcessingResult>();
            var tasks = files.Select(ProcessWordDocumentAsync).ToList();

            var batchResults = await Task.WhenAll(tasks);
            results.AddRange(batchResults);

            return results;
        }

        /// <summary>
        /// 从流中提取文档信息
        /// </summary>
        public async Task<WordDocumentInfo> ExtractDocumentInfoAsync(Stream stream, string fileName)
        {
            var stopwatch = System.Diagnostics.Stopwatch.StartNew();

            try
            {
                // 加载Word文档
                var doc = new Document(stream);

                var documentInfo = new WordDocumentInfo
                {
                    Title = ExtractDocumentTitle(doc),
                    Content = ExtractTextContent(doc),
                    Metadata = ExtractMetadata(doc),
                    Tables = ExtractTables(doc),
                    FormFields = ExtractFormFields(doc),
                    Sections = ExtractSections(doc),
                    ImagesCount = CountImages(doc)
                };

                stopwatch.Stop();
                documentInfo.ProcessingTimeMs = stopwatch.ElapsedMilliseconds;

                return documentInfo;
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "文档信息提取失败: {FileName}", fileName);
                throw;
            }
        }

        /// <summary>
        /// 提取文档标题
        /// </summary>
        private string ExtractDocumentTitle(Document doc)
        {
            try
            {
                // 首先尝试从文档属性获取标题
                var title = doc.BuiltInDocumentProperties.Title;
                if (!string.IsNullOrEmpty(title))
                    return title;

                // 如果没有标题，尝试从第一个段落提取
                foreach (Aspose.Words.Paragraph paragraph in doc.GetChildNodes(NodeType.Paragraph, true))
                {
                    var text = paragraph.GetText().Trim();
                    if (!string.IsNullOrEmpty(text) && text.Length < 100) // 假设标题不会太长
                        return text;
                }

                return "未命名文档";
            }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "提取文档标题失败");
                return "未命名文档";
            }
        }

        /// <summary>
        /// 提取文本内容
        /// </summary>
        private string ExtractTextContent(Document doc)
        {
            try
            {
                // 使用Aspose.Words的GetText方法提取纯文本
                return doc.GetText();
            }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "提取文本内容失败");
                return string.Empty;
            }
        }

        /// <summary>
        /// 提取文档元数据
        /// </summary>
        private DocumentMetadata ExtractMetadata(Document doc)
        {
            try
            {
                var props = doc.BuiltInDocumentProperties;

                return new DocumentMetadata
                {
                    Author = props.Author ?? string.Empty,
                    Company = props.Company ?? string.Empty,
                    CreatedTime = props.CreatedTime,
                    LastSavedTime = props.LastSavedTime,
                    PageCount = doc.PageCount,
                    WordCount = props.Words,
                    CharacterCount = props.Characters,
                    Subject = props.Subject ?? string.Empty,
                    Keywords = props.Keywords ?? string.Empty
                };
            }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "提取元数据失败");
                return new DocumentMetadata();
            }
        }

        /// <summary>
        /// 提取表格数据
        /// </summary>
        private List<DocumentTable> ExtractTables(Document doc)
        {
            var tables = new List<DocumentTable>();

            try
            {
                int tableIndex = 1;
                foreach (Aspose.Words.Tables.Table table in doc.GetChildNodes(NodeType.Table, true))
                {
                    var docTable = new DocumentTable
                    {
                        TableName = $"表格_{tableIndex}"
                    };

                    // 提取表头（假设第一行是表头）
                    if (table.Rows.Count > 0)
                    {
                        var firstRow = table.FirstRow;
                        foreach (Cell cell in firstRow.Cells)
                        {
                            docTable.Headers.Add(cell.GetText().Trim());
                        }
                    }

                    // 提取所有行数据
                    foreach (Row row in table.Rows)
                    {
                        var rowData = new List<string>();
                        foreach (Cell cell in row.Cells)
                        {
                            rowData.Add(cell.GetText().Trim());
                        }
                        docTable.Rows.Add(rowData);
                    }

                    tables.Add(docTable);
                    tableIndex++;
                }
            }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "提取表格数据失败");
            }

            return tables;
        }

        /// <summary>
        /// 提取表单字段
        /// </summary>
        private List<FormField> ExtractFormFields(Document doc)
        {
            var formFields = new List<FormField>();

            try
            {
                foreach (FormField formField in doc.Range.FormFields)
                {
                    formFields.Add(new FormField
                    {
                        Name = formField.Name,
                        Type = formField.Type.ToString()
                        //,
                        //Value = formField.Result ?? string.Empty,
                        //IsChecked = formField.Checked
                    });
                }
            }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "提取表单字段失败");
            }

            return formFields;
        }

        /// <summary>
        /// 提取章节信息
        /// </summary>
        private List<DocumentSection> ExtractSections(Document doc)
        {
            var sections = new List<DocumentSection>();

            try
            {
                int sectionIndex = 1;
                foreach (Section section in doc.Sections)
                {
                    var docSection = new DocumentSection
                    {
                        SectionNumber = sectionIndex,
                        Content = section.GetText(),
                        ParagraphsCount = section.Body.Paragraphs.Count,
                        TablesCount = section.Body.Tables.Count
                    };

                    sections.Add(docSection);
                    sectionIndex++;
                }
            }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "提取章节信息失败");
            }

            return sections;
        }

        /// <summary>
        /// 统计图片数量
        /// </summary>
        private int CountImages(Document doc)
        {
            try
            {
                int imageCount = 0;
                foreach (Aspose.Words.Drawing.Shape shape in doc.GetChildNodes(NodeType.Shape, true))
                {
                    if (shape.HasImage)
                    {
                        imageCount++;
                    }
                }
                return imageCount;
            }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "统计图片数量失败");
                return 0;
            }
        }

        /// <summary>
        /// 检查文件是否为支持的Word格式
        /// </summary>
        public bool IsSupportedWordFormat(string fileName)
        {
            var extension = Path.GetExtension(fileName).ToLower();
            return extension switch
            {
                ".doc" => true,
                ".docx" => true,
                ".dot" => true,
                ".dotx" => true,
                ".docm" => true,
                ".dotm" => true,
                _ => false
            };
        }
    }
}