#define DEBUGOCR
using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Runtime.InteropServices;
using Microsoft.Win32;
using PDFPatcher.Common;
using PDFPatcher.Model;

namespace PDFPatcher.Processor
{
	public class ModiOcr
	{
		//static string _modiPath;
		const string __MachineRegistryPath = @"Installer\Components\61BA386016BD0C340BBEAC273D84FD5F";
		const string __UserRegistryPath = @"Software\Microsoft\Installer\Components\61BA386016BD0C340BBEAC273D84FD5F";

		static readonly List<int> __InstalledLanguage = DetectInstalledLanguages();
		static readonly bool __ModiInstalled = DetectModi();
		public int LangID { get; set; }
		public bool StretchPage { get; set; }
		public bool OrientPage { get; set; }
		public WritingDirection WritingDirection { get; set; }

		public ModiOcr() {
			//if (_modiPath == null) {
			//    _modiPath = FindModi ();
			//}
		}

		internal static bool ModiInstalled => __ModiInstalled;

		#region COMInterop
		static readonly object[] EmptyArray = new object[0];
		static object Create(string type) {
			var t = Type.GetTypeFromProgID(type);
			if (t == null) {
				return null;
			}
			return Activator.CreateInstance(t);
		}
		static object Call(object instance, string method, params object[] parameters) {
			try {
				return instance.GetType().InvokeMember(method, BindingFlags.InvokeMethod, null, instance, parameters);
			}
			catch (Exception ex) {
				if (ex.InnerException != null) {
					throw ex.InnerException;
				}
				throw;
			}
		}
		static object Get(object instance, string propertyName) {
			return instance.GetType().InvokeMember(propertyName, BindingFlags.GetProperty, null, instance, EmptyArray);
		}
		static T Get<T>(object instance, string propertyName) {
			return (T)Get(instance, propertyName);
		}
		static object Get(object instance, string propertyName, int index) {
			return instance.GetType().InvokeMember(propertyName, BindingFlags.GetProperty, null, instance, new object[1] { index });
		}
		static void FinalReleaseComObjects(params object[] objs) {
			for (int i = 0; i < objs.Length; i++) {
				if (objs[i] == null) {
					continue;
				}
				try {
					var r = Marshal.ReleaseComObject(objs[i]);
					System.Diagnostics.Debug.Assert(r == 0);
				}
				catch (Exception ex) {
					System.Diagnostics.Debug.WriteLine("释放对象时出现错误：" + ex.Message);
				}
			}
		}
		#endregion

		static bool DetectModi() {
			if (__InstalledLanguage.Count == 0) {
				return false;
			}
			var ocr = Create("MODI.Document");
			if (ocr == null) {
				return false;
			}
			FinalReleaseComObjects(ocr);
			return true;
		}

		internal static bool IsLanguageInstalled(int langID) {
			return __InstalledLanguage.Contains(langID);
		}

		static List<int> DetectInstalledLanguages() {
			var l = new List<int>();
			try {
				using (var k = Registry.CurrentUser.OpenSubKey(__UserRegistryPath)) {
					DetectInstalledLanguages(k, l);
				}
				using (var k = Registry.ClassesRoot.OpenSubKey(__MachineRegistryPath)) {
					DetectInstalledLanguages(k, l);
				}
			}
			catch (Exception ex) {
				Tracker.DebugMessage("OCR registry error: " + ex.Message);
			}
			return l;
		}

		private static void DetectInstalledLanguages(RegistryKey k, List<int> list) {
			if (k == null) {
				return;
			}
			foreach (var n in k.GetValueNames()) {
				var i = n.ToInt32();
				if (i == 0) {
					continue;
				}
				if (Constants.Ocr.LangIDs.Contains(i) && list.Contains(i) == false) {
					list.Add(i);
				}
			}
		}

		internal void Ocr(string path, string saveImagePath, List<TextLine> results) {
			object ocr = null, images = null, image = null, layout = null;
			object merge = null, mergeImages = null;
			IEnumerable words = null, rects = null;
			TextLine line = null;
			int lineID = -1, regionID = -1;
			int cl, cr;
			TextInfo cti = null;
			try {
#if DEBUGOCR
				Tracker.TraceMessage("创建识别引擎对象。");
#endif
				ocr = Create("MODI.Document");
				var p = Environment.CurrentDirectory;
				//Environment.CurrentDirectory = _modiPath;
#if DEBUGOCR
				Tracker.TraceMessage("读取识别图像：" + path);
#endif
				Call(ocr, "Create", path);
#if DEBUGOCR
				Tracker.TraceMessage("执行识别：" + LangID);
#endif
				Call(ocr, "OCR", ValueHelper.MapValue(LangID, Constants.Ocr.LangIDs, Constants.Ocr.OcrLangIDs), OrientPage, StretchPage);

				Environment.CurrentDirectory = p;
#if DEBUGOCR
				Tracker.TraceMessage("读取识别结果。");
#endif
				images = Get(ocr, "Images");
				image = Get(images, "Item", 0);
				layout = Get(image, "Layout");
#if DEBUGOCR && DEBUG
				var l = new StreamWriter(@"m:\ocr.txt", true, System.Text.Encoding.Default);
				l.WriteLine("path: " + path);
#endif
				words = Get<IEnumerable>(layout, "Words");
				foreach (var word in words) {
					var ti = new TextInfo();
					var w = Get<string>(word, "Text");
					ti.Text = w;
					var pos = new float[4];
					rects = Get<IEnumerable>(word, "Rects");
					foreach (var rect in rects) {
						int r = Get<int>(rect, "Left");
						if (r < pos[0] || pos[0] == 0) {
							pos[0] = r;
						}
						r = Get<int>(rect, "Top");
						if (r > pos[1]) {
							pos[1] = r;
						}
						r = Get<int>(rect, "Right");
						if (r > pos[2]) {
							pos[2] = r;
						}
						r = Get<int>(rect, "Bottom");
						if (r < pos[3] || pos[3] == 0) {
							pos[3] = r;
						}
						FinalReleaseComObjects(rect);
					}
					Marshal.ReleaseComObject(rects);
					ti.Region = new Bound(pos[0], pos[3], pos[2], pos[1]);
					ti.Font = null;
					ti.Size = pos[3] - pos[1];
					if (ti.Text.Length == 1) {
						switch (ti.Text[0]) {
							case '一':
								var r = ti.Region;
								ti.Size = r.Width > r.Height ? r.Width : r.Height;
								var s = (int)Math.Ceiling(ti.Size / 2 - (r.Width > r.Height ? r.Height : r.Width) / 2);
								ti.Region = new Bound(r.Left, r.Bottom + s, r.Right, r.Top - s);
								break;
							case '\u2022':
								ti.Text = "·";
								break;
						}
					}
					if (Char.IsLetterOrDigit(ti.Text[0]) && ti.Size > 0) {
						ti.LetterWidth = ti.Size;
					}
					cl = Get<int>(word, "LineID");
					cr = Get<int>(word, "RegionID");
					var sl = (cl == lineID && cr == regionID); // 处于同一行
					if (sl && WritingDirection != WritingDirection.Unknown) {
						sl = cti != null
								&& cti.Region.IsAlignedWith(ti.Region, WritingDirection);
					}
					if (sl) {
						if (cti != null && cti.Region == ti.Region) {
							cti.Text += ti.Text;
						}
						else {
							line.AddText(ti);
						}
					}
					else {
						if (line != null) {
							results.Add(line);
						}
						line = new TextLine(ti) {
							SuppressTextInfoArrangement = true
						};
						lineID = cl;
						regionID = cr;
					}
					cti = ti;
#if DEBUGOCR && DEBUG
					l.WriteLine(String.Concat(ti.Size, "\t", ti.Text, "\t", ti.Region.Top, " ", ti.Region.Left, " ", ti.Region.Bottom, " ", ti.Region.Right));
#endif
					FinalReleaseComObjects(word);
				}
				Marshal.ReleaseComObject(words);
				if (line != null) {
					results.Add(line);
				}
#if DEBUGOCR && DEBUG
				l.Close();
#endif
				if (FileHelper.IsPathValid(saveImagePath)) {
#if DEBUGOCR
					Tracker.TraceMessage("保存识别后图像路径：" + saveImagePath);
#endif
					if (File.Exists(saveImagePath) == false) {
						Call(ocr, "SaveAs", saveImagePath, -1);
					}
					else {
						merge = Create("MODI.Document");
						Call(merge, "Create", saveImagePath);
						mergeImages = Get(merge, "Images");
						Call(mergeImages, "Add", image, Get(mergeImages, "Item", 0));
						Call(merge, "Save");
					}
				}
#if DEBUGOCR
				Tracker.TraceMessage("完成识别操作。");
#endif
				Call(ocr, "Close", false);
			}
			finally {
#if DEBUGOCR
				Tracker.TraceMessage("释放识别引擎对象。");
#endif
				FinalReleaseComObjects(rects, words, layout, image, images, ocr);
				FinalReleaseComObjects(merge, mergeImages);
				words = rects = null;
				ocr = images = image = layout = null;
				merge = mergeImages = null;
			}

		}

		//private static string FindModi () {
		//    var p = Registry.GetValue (@"HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Shared Tools", "SharedFilesDir", null) as string;
		//    if (p != null && Directory.Exists (p)) {
		//        var m = String.Concat (p, @"\MODI\12.0\");
		//        if (Directory.Exists (m)) {
		//            return m;
		//        }
		//        m = String.Concat (p, @"\MODI\11.0\");
		//        if (Directory.Exists (m)) {
		//            return m;
		//        }
		//    }
		//    throw new FileNotFoundException ("无法找到微软 Office 文档图像处理引擎。");
		//}
	}
}