// BreakpointStore.cs
//
// Author:
//   Lluis Sanchez Gual <lluis@novell.com>
//
// Copyright (c) 2008 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//
//

using System;
using System.IO;
using System.Linq;
using System.Xml;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Runtime.InteropServices;
using System.Collections.Concurrent;

namespace Mono.Debugging.Client
{
	public sealed class BreakpointStore: ICollection<BreakEvent>
	{
		static readonly StringComparer PathComparer;
		static readonly bool IsWindows;
		static readonly bool IsMac;

		readonly object breakpointLock = new object ();
		List<BreakEvent> breakpoints = new List<BreakEvent>();

		static BreakpointStore ()
		{
			IsWindows = Path.DirectorySeparatorChar == '\\';
			IsMac = !IsWindows && IsRunningOnMac ();

			PathComparer = IsWindows || IsMac ? StringComparer.OrdinalIgnoreCase : StringComparer.Ordinal;
		}

		[DllImport ("libc")]
		static extern int uname (IntPtr buf);

		//From Managed.Windows.Forms/XplatUI
		static bool IsRunningOnMac ()
		{
			var buf = IntPtr.Zero;

			try {
				buf = Marshal.AllocHGlobal (8192);
				// This is a hacktastic way of getting sysname from uname ()
				if (uname (buf) == 0) {
					var os = Marshal.PtrToStringAnsi (buf);
					if (os == "Darwin")
						return true;
				}
			} catch {
			} finally {
				if (buf != IntPtr.Zero)
					Marshal.FreeHGlobal (buf);
			}
			return false;
		}

		public int Count {
			get {
				return InternalGetBreakpoints().Count;
			}
		}

		public bool IsReadOnly {
			get {
				var args = new ReadOnlyCheckEventArgs ();
				CheckingReadOnly?.Invoke (this, args);
				return args.IsReadOnly;
			}
		}

		public Breakpoint Add (string filename, int line, int column)
		{
			return Add (filename, line, column, true);
		}

		public Breakpoint Add (string filename, int line)
		{
			return Add (filename, line, 1, true);
		}

		public Breakpoint Add (string filename, int line, int column, bool activate)
		{
			if (filename == null)
				throw new ArgumentNullException (nameof (filename));

			if (line < 1)
				throw new ArgumentOutOfRangeException (nameof (line));

			if (column < 1)
				throw new ArgumentOutOfRangeException (nameof (column));

			if (IsReadOnly)
				return null;

			var bp = new Breakpoint (filename, line, column);
			Add (bp);

			return bp;
		}

		void ICollection<BreakEvent>.Add (BreakEvent bp)
		{
			Add (bp);
		}

		public bool Add (BreakEvent be)
		{
			if (be == null)
				throw new ArgumentNullException (nameof (be));

			if (IsReadOnly)
				return false;

			if (be is Breakpoint bp) {
				bp.SetFileName (ResolveFullPath(bp.FileName));
			}

			lock (breakpointLock) {
				breakpoints.Add(be);
				SetBreakpoints(breakpoints);
				be.Store = this;
			}

			OnBreakEventAdded (be);

			return true;
		}

		public Catchpoint AddCatchpoint (string exceptionName)
		{
			return AddCatchpoint (exceptionName, true);
		}

		public Catchpoint AddCatchpoint (string exceptionName, bool includeSubclasses)
		{
			if (exceptionName == null)
				throw new ArgumentNullException (nameof (exceptionName));

			if (IsReadOnly)
				return null;

			var cp = new Catchpoint (exceptionName, includeSubclasses);
			Add (cp);

			return cp;
		}

		public bool Remove (string filename, int line, int column)
		{
			if (filename == null)
				throw new ArgumentNullException (nameof (filename));

			if (IsReadOnly)
				return false;

			filename = Path.GetFullPath (filename);

			var breakpointsToRemove = new List<BreakEvent> ();
			foreach (var b in InternalGetBreakpoints ()) {
				if (b is Breakpoint bp && FileNameEquals(bp.FileName, filename) &&
					(bp.OriginalLine == line || bp.Line == line) &&
					(bp.OriginalColumn == column || bp.Column == column)) {
					breakpointsToRemove.Add (bp);
				}
			}

			RemoveRange (breakpointsToRemove);

			return true;
		}

		public bool RemoveCatchpoint (string exceptionName)
		{
			if (exceptionName == null)
				throw new ArgumentNullException (nameof (exceptionName));

			if (IsReadOnly)
				return false;

			var breakpointsToRemove = new List<BreakEvent> ();
			foreach (var b in InternalGetBreakpoints ()) {
				if (b is Catchpoint cp && cp.ExceptionName == exceptionName) {
					breakpointsToRemove.Add (cp);
				}
			}

			RemoveRange (breakpointsToRemove);

			return true;
		}

		public void RemoveRunToCursorBreakpoints ()
		{
			if (IsReadOnly)
				return;

			var breakpointsToRemove = InternalGetBreakpoints ().OfType<RunToCursorBreakpoint> ().ToList ();

			RemoveRange (breakpointsToRemove);
		}

		public bool Remove (BreakEvent bp)
		{
			if (bp == null)
				throw new ArgumentNullException (nameof (bp));


			if (!IsReadOnly) {
				var wasRemoved = false;
				lock (breakpointLock) {
					if (breakpoints.Contains (bp)) {
						breakpoints.Remove(bp);
						SetBreakpoints(breakpoints);
						wasRemoved = true;
					}
				}

				if (wasRemoved) {
					OnBreakEventRemoved (bp);
					return true;
				}
			}

			return false;
		}

		void RemoveRange (IEnumerable<BreakEvent> breakEvents)
		{
			List<BreakEvent> oldEvents;

			if (!IsReadOnly) {
				lock (breakpointLock) {
					foreach (var b in breakEvents)
						breakpoints.Remove(b);
					oldEvents = SetBreakpoints(breakpoints);
				}

				List<BreakEvent> breakEventsRemoved = new List<BreakEvent> ();

				foreach (var bp in breakEvents) {
					if (oldEvents.Contains(bp)) {
						breakEventsRemoved.Add (bp);
					}
				}

				OnBreakEventsRemoved (breakEventsRemoved);
			}
		}

		public Breakpoint Toggle (string filename, int line, int column)
		{
			if (filename == null)
				throw new ArgumentNullException (nameof (filename));

			if (line < 1)
				throw new ArgumentOutOfRangeException (nameof (line));

			if (column < 1)
				throw new ArgumentOutOfRangeException (nameof (column));

			if (IsReadOnly)
				return null;

			var col = GetBreakpointsAtFileLine (filename, line);
			if (col.Count > 0) {
				// Remove only the most-recently-added breakpoint on the specified line
				Remove (col[col.Count - 1]);
				return null;
			}

			return Add (filename, line, column);
		}

		public ReadOnlyCollection<BreakEvent> GetBreakevents ()
		{
			return new ReadOnlyCollection<BreakEvent>(InternalGetBreakpoints ());
		}

		public ReadOnlyCollection<Breakpoint> GetBreakpoints ()
		{
			var list = new List<Breakpoint> ();

			foreach (var bp in InternalGetBreakpoints ().OfType<Breakpoint> ()) {
				if (!(bp is RunToCursorBreakpoint))
					list.Add (bp);
			}

			return list.AsReadOnly ();
		}

		public ReadOnlyCollection<Catchpoint> GetCatchpoints ()
		{
			return InternalGetBreakpoints ().OfType<Catchpoint> ().ToList ().AsReadOnly ();
		}

		public ReadOnlyCollection<Breakpoint> GetBreakpointsAtFile (string filename)
		{
			if (filename == null)
				throw new ArgumentNullException (nameof (filename));

			var list = new List<Breakpoint> ();
			if (string.IsNullOrEmpty (filename))
				return list.AsReadOnly ();

			try {
				filename = Path.GetFullPath (filename);
			} catch {
				return list.AsReadOnly ();
			}

			foreach (var bp in InternalGetBreakpoints ().OfType<Breakpoint> ()) {
				if (!(bp is RunToCursorBreakpoint) && FileNameEquals(bp.FileName, filename))
					list.Add (bp);
			}

			return list.AsReadOnly ();
		}

		public ReadOnlyCollection<Breakpoint> GetBreakpointsAtFileLine (string filename, int line)
		{
			if (filename == null)
				throw new ArgumentNullException (nameof (filename));

			var list = new List<Breakpoint> ();

			try {
				filename = Path.GetFullPath (filename);
			} catch {
				return list.AsReadOnly ();
			}

			foreach (var bp in InternalGetBreakpoints ().OfType<Breakpoint> ()) {
				if (!(bp is RunToCursorBreakpoint) && FileNameEquals(bp.FileName, filename) && (bp.OriginalLine == line || bp.Line == line))
					list.Add (bp);
			}

			return list.AsReadOnly ();
		}

		public IEnumerator GetEnumerator ()
		{
			return ((IEnumerable)InternalGetBreakpoints()).GetEnumerator ();
		}

		IEnumerator<BreakEvent> IEnumerable<BreakEvent>.GetEnumerator ()
		{
			return ((IEnumerable<BreakEvent>)InternalGetBreakpoints ()).GetEnumerator ();
		}

		public void Clear ()
		{
			Clear (true);
		}

		public void Clear (bool clearNonUserBreakpoints)
		{
			var breakpointsToRemove = InternalGetBreakpoints ()
				.Where (bp => clearNonUserBreakpoints || !bp.NonUserBreakpoint);

			RemoveRange (breakpointsToRemove);
		}

		public void ClearBreakpoints ()
		{
			RemoveRange (GetBreakpoints ());
		}

		public void ClearCatchpoints ()
		{
			RemoveRange (GetCatchpoints ());
		}

		public bool Contains (BreakEvent item)
		{
			return InternalGetBreakpoints ().Contains (item);
		}

		public void CopyTo (BreakEvent[] array, int arrayIndex)
		{
			InternalGetBreakpoints ().CopyTo (array, arrayIndex);
		}

		public void UpdateBreakpointLine (Breakpoint bp, int newLine)
		{
			if (IsReadOnly)
				return;

			bp.SetLine (newLine);
			NotifyBreakEventChanged (bp);
		}

		internal void AdjustBreakpointLine (Breakpoint bp, int newLine, int newColumn)
		{
			if (IsReadOnly)
				return;

			bp.SetAdjustedColumn (newColumn);
			bp.SetAdjustedLine (newLine);
			NotifyBreakEventChanged (bp);
		}

		internal void ResetBreakpoints ()
		{
			if (IsReadOnly)
				return;

			foreach (var bp in InternalGetBreakpoints ()) {
				if (bp.Reset ()) {
					NotifyBreakEventChanged (bp);
				}
			}
		}

		public XmlElement Save (string baseDir = null)
		{
			XmlDocument doc = new XmlDocument ();
			XmlElement elem = doc.CreateElement ("BreakpointStore");
			foreach (BreakEvent ev in this) {
				if (ev.NonUserBreakpoint)
					continue;
				XmlElement be = ev.ToXml (doc, baseDir);
				elem.AppendChild (be);
			}
			return elem;
		}

		public void Load (XmlElement rootElem, string baseDir = null)
		{
			Clear ();

			var loadedBreakpoints = new List<BreakEvent> ();
			foreach (XmlNode n in rootElem.ChildNodes) {
				XmlElement elem = n as XmlElement;
				if (elem == null)
					continue;
				BreakEvent ev = BreakEvent.FromXml (elem, baseDir);
				if (ev != null) {
					loadedBreakpoints.Add (ev);
					ev.Store = this;
				}
			}

			lock (breakpointLock) {
				SetBreakpoints (new List<BreakEvent> (loadedBreakpoints));
			}

			// preserve behaviour by sending an event for each breakpoint that was loaded
			OnBreakEventsAdded (loadedBreakpoints);
		}

		[DllImport("libc")]
		static extern string realpath(string path, IntPtr buffer);

		/// <summary>
		/// Resolves the full path of the given file
		/// </summary>
		/// <param name="path"></param>
		/// <returns>The full path if a file is given, or returns the parameter if it is null or empty</returns>
		static string ResolveFullPath (string path)
		{
			// If there is no path given, return the same path back
			if (string.IsNullOrEmpty(path))
				return path;

			string result = null;
			try {
				result = realpath(path, IntPtr.Zero);
			}
			catch {
			}

			return string.IsNullOrEmpty(result) ? Path.GetFullPath(path) : result;
		}

		public static bool FileNameEquals (string file1, string file2)
		{
			if (file1 == null)
				return file2 == null;

			if (file2 == null)
				return false;

			return PathComparer.Compare (file1, file2) == 0;
		}

		internal bool EnableBreakEvent (BreakEvent be, bool previouslyEnabled, bool enabled)
		{
			if (IsReadOnly)
				return false;

			if (previouslyEnabled != enabled) {
				OnChanged ();
				BreakEventEnableStatusChanged?.Invoke (this, new BreakEventArgs (be));
				NotifyStatusChanged (be);
			}

			return true;
		}

		void OnBreakEventAdded (BreakEvent be)
		{
			BreakEventAdded?.Invoke (this, new BreakEventArgs (be));
			if (be is Breakpoint bp) {
				BreakpointAdded?.Invoke (this, new BreakpointEventArgs (bp));
			} else if (be is Catchpoint ce) {
				CatchpointAdded?.Invoke (this, new CatchpointEventArgs (ce));
			}
			OnChanged ();
		}

		void OnBreakEventsAdded (List<BreakEvent> bes)
		{
			foreach (BreakEvent be in bes) {
				BreakEventAdded?.Invoke (this, new BreakEventArgs (be));
				if (be is Breakpoint bp) {
					BreakpointAdded?.Invoke (this, new BreakpointEventArgs (bp));
				} else if (be is Catchpoint ce) {
					CatchpointAdded?.Invoke (this, new CatchpointEventArgs (ce));
				}
			}

			OnChanged ();
		}

		void OnBreakEventRemoved (BreakEvent be)
		{
			BreakEventRemoved?.Invoke (this, new BreakEventArgs (be));
			if (be is Breakpoint bp) {
				BreakpointRemoved?.Invoke (this, new BreakpointEventArgs (bp));
			} else if (be is Catchpoint ce) {
				CatchpointRemoved?.Invoke (this, new CatchpointEventArgs (ce));
			}
			OnChanged ();
		}

		void OnBreakEventsRemoved (List<BreakEvent> bes)
		{
			foreach (BreakEvent be in bes) {
				BreakEventRemoved?.Invoke (this, new BreakEventArgs (be));
				if (be is Breakpoint bp) {
					BreakpointRemoved?.Invoke (this, new BreakpointEventArgs (bp));
				} else if (be is Catchpoint ce) {
					CatchpointRemoved?.Invoke (this, new CatchpointEventArgs (ce));
				}
			}

			OnChanged ();
		}

		void OnChanged ()
		{
			Changed?.Invoke (this, EventArgs.Empty);
		}

		internal void NotifyStatusChanged (BreakEvent be)
		{
			try {
				BreakEventStatusChanged?.Invoke (this, new BreakEventArgs (be));
				if (be is Breakpoint bp) {
					BreakpointStatusChanged?.Invoke (this, new BreakpointEventArgs (bp));
				} else if (be is Catchpoint ce) {
					CatchpointStatusChanged?.Invoke (this, new CatchpointEventArgs (ce));
				}
			} catch {
				// Ignore
			}
		}

		internal void NotifyBreakEventChanged (BreakEvent be)
		{
			try {
				BreakEventModified?.Invoke (this, new BreakEventArgs (be));
				if (be is Breakpoint bp) {
					BreakpointModified?.Invoke (this, new BreakpointEventArgs (bp));
				} else if (be is Catchpoint ce) {
					CatchpointModified?.Invoke (this, new CatchpointEventArgs (ce));
				}
				OnChanged ();
			} catch {
				// Ignore
			}
		}

		internal void NotifyBreakEventUpdated (BreakEvent be)
		{

			try {
				BreakEventUpdated?.Invoke (this, new BreakEventArgs (be));
				if (be is Breakpoint bp) {
					BreakpointUpdated?.Invoke (this, new BreakpointEventArgs (bp));
				} else if (be is Catchpoint ce) {
					CatchpointUpdated?.Invoke (this, new CatchpointEventArgs (ce));
				}
			} catch {
				// Ignore
			}
		}

		public event EventHandler<BreakpointEventArgs> BreakpointAdded;
		public event EventHandler<BreakpointEventArgs> BreakpointRemoved;
		public event EventHandler<BreakpointEventArgs> BreakpointStatusChanged;
		public event EventHandler<BreakpointEventArgs> BreakpointModified;
		public event EventHandler<BreakpointEventArgs> BreakpointUpdated;
		public event EventHandler<CatchpointEventArgs> CatchpointAdded;
		public event EventHandler<CatchpointEventArgs> CatchpointRemoved;
		public event EventHandler<CatchpointEventArgs> CatchpointStatusChanged;
		public event EventHandler<CatchpointEventArgs> CatchpointModified;
		public event EventHandler<CatchpointEventArgs> CatchpointUpdated;
		public event EventHandler<BreakEventArgs> BreakEventAdded;
		public event EventHandler<BreakEventArgs> BreakEventRemoved;
		public event EventHandler<BreakEventArgs> BreakEventStatusChanged;
		public event EventHandler<BreakEventArgs> BreakEventModified;
		public event EventHandler<BreakEventArgs> BreakEventUpdated;
		public event EventHandler Changed;
		public event EventHandler<ReadOnlyCheckEventArgs> CheckingReadOnly;

		internal event EventHandler<BreakEventArgs> BreakEventEnableStatusChanged;

		public void FileRenamed (string oldPath, string newPath)
		{
			if (IsReadOnly)
				return;

			foreach (var bp in GetBreakpointsAtFile (oldPath)) {
				Remove (bp);
				bp.SetFileName (newPath);
				Add (bp);
			}
		}

		List<BreakEvent> SetBreakpoints (List<BreakEvent> newBreakpoints)
		{
			System.Diagnostics.Debug.Assert (System.Threading.Monitor.IsEntered (breakpointLock), "SetBreakpoints must be called during a lock");

			foreach (BreakEvent be in newBreakpoints) {
				if (be is Breakpoint bp) {
					bp.SetFileName (ResolveFullPath(bp.FileName));
				}
			}

			var oldEvents = breakpoints;
			breakpoints = newBreakpoints;
			return oldEvents;
		}

		List<BreakEvent> InternalGetBreakpoints ()
		{
			lock (breakpointLock) {
				return breakpoints;
			}
		}
	}

	public class ReadOnlyCheckEventArgs: EventArgs
	{
		internal bool IsReadOnly;

		public void SetReadOnly (bool isReadOnly)
		{
			IsReadOnly = IsReadOnly || isReadOnly;
		}
	}
}