//
// Mono.Cairo.Context.cs
//
// Author:
//   Duncan Mak (duncan@ximian.com)
//   Miguel de Icaza (miguel@novell.com)
//   Hisham Mardam Bey (hisham.mardambey@gmail.com)
//   Alp Toker (alp@atoker.com)
//
// (C) Ximian Inc, 2003.
// (C) Novell Inc, 2003.
//
// This is an OO wrapper API for the Cairo API.
//
// Copyright (C) 2004 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.Runtime.InteropServices;
using System.Text;
using Drawing2D;

namespace Crow.CairoBackend
{
	public class Context : IContext
	{
		internal IntPtr handle = IntPtr.Zero;

		static int native_glyph_size, c_compiler_long_size;

		static Context ()
		{
			//
			// This is used to determine what kind of structure
			// we should use to marshal Glyphs, as the public
			// definition in Cairo uses `long', which can be
			// 32 bits or 64 bits depending on the platform.
			//
			// We assume that sizeof(long) == sizeof(void*)
			// except in the case of Win64 where sizeof(long)
			// is 32 bits
			//
			int ptr_size = Marshal.SizeOf (typeof (IntPtr));

			PlatformID platform = Environment.OSVersion.Platform;
			if (platform == PlatformID.Win32NT ||
			    platform == PlatformID.Win32S ||
			    platform == PlatformID.Win32Windows ||
			    platform == PlatformID.WinCE ||
			    ptr_size == 4){
				c_compiler_long_size = 4;
				native_glyph_size = Marshal.SizeOf (typeof (NativeGlyph_4byte_longs));
			} else {
				c_compiler_long_size = 8;
				native_glyph_size = Marshal.SizeOf (typeof (Glyph));
			}
		}

		internal Context (Surface surface) : this (NativeMethods.cairo_create (surface.handle), true)
		{
		}


		internal Context (IntPtr handle, bool owner)
		{
			this.handle = handle;
			if (!owner)
				NativeMethods.cairo_reference (handle);
			if (CairoDebug.Enabled)
				CairoDebug.OnAllocated (handle);
		}

		[Obsolete]
		internal Context (IntPtr state) : this (state, true)
		{
		}

		~Context ()
		{
			Dispose (false);
		}

		public void Dispose ()
		{
			Dispose (true);
			GC.SuppressFinalize (this);
		}

		protected virtual void Dispose (bool disposing)
		{
			if (!disposing || CairoDebug.Enabled)
				CairoDebug.OnDisposed<Context> (handle, disposing);

			if (!disposing|| handle == IntPtr.Zero)
				return;

			NativeMethods.cairo_destroy (handle);
			handle = IntPtr.Zero;

		}

		public void Save ()
		{
			NativeMethods.cairo_save (handle);
		}

		public void Restore ()
		{
			NativeMethods.cairo_restore (handle);
		}

		public Antialias Antialias {
			get { return NativeMethods.cairo_get_antialias (handle); }
			set { NativeMethods.cairo_set_antialias (handle, value); }
		}

		public Status Status {
			get {
				return NativeMethods.cairo_status (handle);
			}
		}
		public string StatusString {
			get {
				return System.Runtime.InteropServices.Marshal.PtrToStringAuto(NativeMethods.cairo_status_to_string (Status));
			}
		}

		public Operator Operator {
			set => NativeMethods.cairo_set_operator (handle, value);
			get => NativeMethods.cairo_get_operator (handle);
		}
		public double Tolerance {
			get => NativeMethods.cairo_get_tolerance (handle);
			set => NativeMethods.cairo_set_tolerance (handle, value);
		}
		public FillRule FillRule {
			set => NativeMethods.cairo_set_fill_rule (handle, value);
			get => NativeMethods.cairo_get_fill_rule (handle);
		}
		public double LineWidth {
			set => NativeMethods.cairo_set_line_width (handle, value);
			get => NativeMethods.cairo_get_line_width (handle);
		}
		public LineCap LineCap {
			set => NativeMethods.cairo_set_line_cap (handle, value);
			get => NativeMethods.cairo_get_line_cap (handle);
		}
		public LineJoin LineJoin {
			set => NativeMethods.cairo_set_line_join (handle, value);
			get => NativeMethods.cairo_get_line_join (handle);
		}
		public double MiterLimit {
			set => NativeMethods.cairo_set_miter_limit (handle, value);
			get => NativeMethods.cairo_get_miter_limit (handle);
		}

		public void SetDash (double [] dashes, double offset = 0)
			=> NativeMethods.cairo_set_dash (handle, dashes, dashes.Length, offset);

		public void SetSource (Pattern source)
			=> NativeMethods.cairo_set_source (handle, source.handle);
		public Pattern GetSource ()
		{
			var ptr = NativeMethods.cairo_get_source (handle);
			return Pattern.Lookup (ptr, false);
		}


		public PointD CurrentPoint {
			get {
				double x, y;
				NativeMethods.cairo_get_current_point (handle, out x, out y);
				return new PointD (x, y);
			}
		}

		public bool HasCurrentPoint => NativeMethods.cairo_has_current_point (handle);
		public Surface GetTarget () =>  Surface.Lookup (NativeMethods.cairo_get_target (handle), false);
		public void SetTarget (Surface target)
		{
			if (handle != IntPtr.Zero)
				NativeMethods.cairo_destroy (handle);
			handle = NativeMethods.cairo_create (target.handle);
		}
		public ScaledFont GetScaledFont ()
			=> new ScaledFont (NativeMethods.cairo_get_scaled_font (handle), false);
		public void SetScaledFont (ScaledFont font)
			=> NativeMethods.cairo_set_scaled_font (handle, font.Handle);
		public uint ReferenceCount => NativeMethods.cairo_get_reference_count (handle);
		public void SetSource (Color color)
			=> NativeMethods.cairo_set_source_rgba (handle, color.R / 255.0, color.G / 255.0, color.B / 255.0, color.A / 255.0);
		public void SetSource (double r, double g, double b)
		{
			NativeMethods.cairo_set_source_rgb (handle, r, g, b);
		}

		public void SetSource (double r, double g, double b, double a)
		{
			NativeMethods.cairo_set_source_rgba (handle, r, g, b, a);
		}

		//[Obsolete ("Use SetSource method (with double parameters)")]
		public void SetSource (Surface source, int x = 0, int y = 0)
		{
			NativeMethods.cairo_set_source_surface (handle, source.handle, x, y);
		}

		public void SetSource (Surface source, double x, double y)
		{
			NativeMethods.cairo_set_source_surface (handle, source.handle, x, y);
		}

		public void SetSource (Surface source)
		{
			NativeMethods.cairo_set_source_surface (handle, source.handle, 0, 0);
		}

		#region Path methods
		public void NewPath () => NativeMethods.cairo_new_path (handle);
		public void NewSubPath () => NativeMethods.cairo_new_sub_path (handle);
		public void MoveTo (PointD p) => MoveTo (p.X, p.Y);
		public void MoveTo (double x, double y) => NativeMethods.cairo_move_to (handle, x, y);
		public void LineTo (PointD p) => LineTo (p.X, p.Y);
		public void LineTo (double x, double y) => NativeMethods.cairo_line_to (handle, x, y);
		public void CurveTo (PointD p1, PointD p2, PointD p3) => CurveTo (p1.X, p1.Y, p2.X, p2.Y, p3.X, p3.Y);
		public void CurveTo (double x1, double y1, double x2, double y2, double x3, double y3)
			=> NativeMethods.cairo_curve_to (handle, x1, y1, x2, y2, x3, y3);
		public void RelMoveTo (Distance d) => RelMoveTo (d.Dx, d.Dy);
		public void RelMoveTo (double dx, double dy) => NativeMethods.cairo_rel_move_to (handle, dx, dy);
		public void RelLineTo (Distance d) => RelLineTo (d.Dx, d.Dy);
		public void RelLineTo (double dx, double dy) =>	NativeMethods.cairo_rel_line_to (handle, dx, dy);
		public void RelCurveTo (Distance d1, Distance d2, Distance d3)
			=> RelCurveTo (d1.Dx, d1.Dy, d2.Dx, d2.Dy, d3.Dx, d3.Dy);
		public void RelCurveTo (double dx1, double dy1, double dx2, double dy2, double dx3, double dy3)
			=> NativeMethods.cairo_rel_curve_to (handle, dx1, dy1, dx2, dy2, dx3, dy3);
		public void Arc (double xc, double yc, double radius, double angle1, double angle2)
			=> NativeMethods.cairo_arc (handle, xc, yc, radius, angle1, angle2);
		public void Arc (PointD center, double radius, double angle1, double angle2)
			=> NativeMethods.cairo_arc (handle, center.X, center.Y, radius, angle1, angle2);
		public void ArcNegative (double xc, double yc, double radius, double angle1, double angle2)
			=> NativeMethods.cairo_arc_negative (handle, xc, yc, radius, angle1, angle2);
		public void ArcNegative (PointD center, double radius, double angle1, double angle2)
			=> NativeMethods.cairo_arc_negative (handle, center.X, center.Y, radius, angle1, angle2);
		public void Rectangle (Rectangle rectangle)
			=> Rectangle (rectangle.X, rectangle.Y, rectangle.Width, rectangle.Height);
		public void Rectangle (RectangleD rectangle)
			=> Rectangle (rectangle.X, rectangle.Y, rectangle.Width, rectangle.Height);
		public void Rectangle (PointD p, double width, double height)
			=> Rectangle (p.X, p.Y, width, height);
		public void Rectangle (double x, double y, double width, double height)
			=> NativeMethods.cairo_rectangle (handle, x, y, width, height);
		public void ClosePath () => NativeMethods.cairo_close_path (handle);
		public Path CopyPath () => new Path (NativeMethods.cairo_copy_path (handle));
		public Path CopyPathFlat () => new Path (NativeMethods.cairo_copy_path_flat (handle));
		public void AppendPath (Path path) => NativeMethods.cairo_append_path (handle, path.Handle);
		#endregion

		#region Painting Methods
		public void Paint () => NativeMethods.cairo_paint (handle);
		public void PaintWithAlpha (double alpha) => NativeMethods.cairo_paint_with_alpha (handle, alpha);
		public void Mask (Pattern pattern) => NativeMethods.cairo_mask (handle, pattern.handle);
		public void MaskSurface (Surface surface, double surface_x, double surface_y)
			=> NativeMethods.cairo_mask_surface (handle, surface.handle, surface_x, surface_y);
		public void Stroke () => NativeMethods.cairo_stroke (handle);
		public void StrokePreserve () => NativeMethods.cairo_stroke_preserve (handle);
		public Rectangle StrokeExtents ()
		{
			double x1, y1, x2, y2;
			NativeMethods.cairo_stroke_extents (handle, out x1, out y1, out x2, out y2);
			return new Rectangle ((int)x1, (int)y1, (int)(x2 - x1), (int)(y2 - y1));
		}

		public void Fill () => NativeMethods.cairo_fill (handle);
		public void FillPreserve () => NativeMethods.cairo_fill_preserve (handle);
		public Rectangle FillExtents ()
		{
			double x1, y1, x2, y2;
			NativeMethods.cairo_fill_extents (handle, out x1, out y1, out x2, out y2);
			return new Rectangle ((int)x1, (int)y1, (int)(x2 - x1), (int)(y2 - y1));
		}

		#endregion

		public void Clip () => NativeMethods.cairo_clip (handle);
		public void ClipPreserve () => NativeMethods.cairo_clip_preserve (handle);
		public void ResetClip () => NativeMethods.cairo_reset_clip (handle);
		public bool InClip (double x, double y) => NativeMethods.cairo_in_clip (handle, x, y);
		/*public RectangleList GetClipRectangles (){
			return (RectangleList)Marshal.PtrToStructure (NativeMethods.cairo_copy_clip_rectangle_list (handle), typeof(RectangleList));
		}*/
		public void ClipExtendRectangle (){
			double x1, y1, x2, y2;
			NativeMethods.cairo_clip_extents (handle, out x1, out y1, out x2, out y2);
			NativeMethods.cairo_rectangle (handle, x1, y1, x2 - x1, y2 - y1);
		}
		public bool InStroke (double x, double y) => NativeMethods.cairo_in_stroke (handle, x, y);
		public bool InFill (double x, double y) => NativeMethods.cairo_in_fill (handle, x, y);
		public Pattern PopGroup () => Pattern.Lookup (NativeMethods.cairo_pop_group (handle), true);
		public void PopGroupToSource () => NativeMethods.cairo_pop_group_to_source (handle);
		public void PushGroup () => NativeMethods.cairo_push_group (handle);
		public void PushGroup (Content content) => NativeMethods.cairo_push_group_with_content (handle, content);
		public Surface GetGroupTarget ()
		{
			IntPtr surface = NativeMethods.cairo_get_group_target (handle);
			return Surface.Lookup (surface, false);
		}

		public void Rotate (double angle) => NativeMethods.cairo_rotate (handle, angle);
		public void Scale (double sx, double sy) => NativeMethods.cairo_scale (handle, sx, sy);
		public void Translate (double tx, double ty) => NativeMethods.cairo_translate (handle, tx, ty);
		public void Transform (Matrix m) => NativeMethods.cairo_transform (handle, m);

		[Obsolete("Use UserToDevice instead")]
		public void TransformPoint (ref double x, ref double y)
		{
			NativeMethods.cairo_user_to_device (handle, ref x, ref y);
		}

		[Obsolete("Use UserToDeviceDistance instead")]
		public void TransformDistance (ref double dx, ref double dy)
		{
			NativeMethods.cairo_user_to_device_distance (handle, ref dx, ref dy);
		}

		[Obsolete("Use InverseTransformPoint instead")]
		public void InverseTransformPoint (ref double x, ref double y)
		{
			NativeMethods.cairo_device_to_user (handle, ref x, ref y);
		}

		[Obsolete("Use DeviceToUserDistance instead")]
		public void InverseTransformDistance (ref double dx, ref double dy)
		{
			NativeMethods.cairo_device_to_user_distance (handle, ref dx, ref dy);
		}

		public void UserToDevice (ref double x, ref double y)
		{
			NativeMethods.cairo_user_to_device (handle, ref x, ref y);
		}

		public void UserToDeviceDistance (ref double dx, ref double dy)
		{
			NativeMethods.cairo_user_to_device_distance (handle, ref dx, ref dy);
		}

		public void DeviceToUser (ref double x, ref double y)
		{
			NativeMethods.cairo_device_to_user (handle, ref x, ref y);
		}

		public void DeviceToUserDistance (ref double dx, ref double dy)
		{
			NativeMethods.cairo_device_to_user_distance (handle, ref dx, ref dy);
		}

		public void SetFontSize (double scale)
		{
			NativeMethods.cairo_set_font_size (handle, scale);
		}

		public void IdentityMatrix () => NativeMethods.cairo_identity_matrix (handle);
		public Matrix FontMatrix {
			get {
				Matrix m;
				NativeMethods.cairo_get_font_matrix (handle, out m);
				return m;
			}
			set { NativeMethods.cairo_set_font_matrix (handle, value); }
		}

		public FontOptions FontOptions {
			get {
				FontOptions options = new FontOptions ();
				NativeMethods.cairo_get_font_options (handle, options.Handle);
				return options;
			}
			set { NativeMethods.cairo_set_font_options (handle, value.Handle); }
		}

		[StructLayout(LayoutKind.Sequential)]
		internal struct NativeGlyph_4byte_longs {
			public int index;
			public double x;
			public double y;

			public NativeGlyph_4byte_longs (Glyph source)
			{
				index = (int) source.index;
				x = source.x;
				y = source.y;
			}
		}

		static internal IntPtr FromGlyphToUnManagedMemory(Glyph [] glyphs)
		{
			IntPtr dest = Marshal.AllocHGlobal (native_glyph_size * glyphs.Length);
			long pos = dest.ToInt64();

			if (c_compiler_long_size == 8){
				foreach (Glyph g in glyphs){
					Marshal.StructureToPtr (g, (IntPtr)pos, false);
					pos += native_glyph_size;
				}
			} else {
				foreach (Glyph g in glyphs){
					NativeGlyph_4byte_longs n = new NativeGlyph_4byte_longs (g);

					Marshal.StructureToPtr (n, (IntPtr)pos, false);
					pos += native_glyph_size;
				}
			}

			return dest;
		}

		public void ShowGlyphs (Glyph[] glyphs)
		{
			IntPtr ptr;

			ptr = FromGlyphToUnManagedMemory (glyphs);

			NativeMethods.cairo_show_glyphs (handle, ptr, glyphs.Length);

			Marshal.FreeHGlobal (ptr);
		}

		[Obsolete("The matrix argument was never used, use ShowGlyphs(Glyphs []) instead")]
		public void ShowGlyphs (Matrix matrix, Glyph[] glyphs)
		{
			ShowGlyphs (glyphs);
		}

		[Obsolete("The matrix argument was never used, use GlyphPath(Glyphs []) instead")]
		public void GlyphPath (Matrix matrix, Glyph[] glyphs)
		{
			GlyphPath (glyphs);
		}

		public void GlyphPath (Glyph[] glyphs)
		{
			IntPtr ptr;

			ptr = FromGlyphToUnManagedMemory (glyphs);

			NativeMethods.cairo_glyph_path (handle, ptr, glyphs.Length);

			Marshal.FreeHGlobal (ptr);

		}

		public FontExtents FontExtents {
			get {
				FontExtents f_extents;
				NativeMethods.cairo_font_extents (handle, out f_extents);
				return f_extents;
			}
		}

		public void CopyPage ()
		{
			NativeMethods.cairo_copy_page (handle);
		}

		public void SetContextFontFace (FontFace value)
		{
			NativeMethods.cairo_set_font_face (handle, value == null ? IntPtr.Zero : value.Handle);
		}

		public void SelectFontFace (string family, FontSlant slant, FontWeight weight)
		{
			NativeMethods.cairo_select_font_face (handle, family, slant, weight);
		}

		public void ShowPage ()
		{
			NativeMethods.cairo_show_page (handle);
		}

		private static byte[] TerminateUtf8(byte[] utf8)
		{
			if (utf8.Length > 0 && utf8[utf8.Length - 1] == 0)
				return utf8;
			var termedArray = new byte[utf8.Length + 1];
			Array.Copy(utf8, termedArray, utf8.Length);
			termedArray[utf8.Length] = 0;
			return termedArray;
		}

		private static byte[] TerminateUtf8(string s)
		{
			// compute the byte count including the trailing \0
			var byteCount = Encoding.UTF8.GetMaxByteCount(s.Length + 1);
			var bytes = new byte[byteCount];
			Encoding.UTF8.GetBytes(s, 0, s.Length, bytes, 0);
			return bytes;
		}

		public void ShowText(string str)
			=> NativeMethods.cairo_show_text (handle, TerminateUtf8 (str));
		public void TextPath(string str)
			=> NativeMethods.cairo_text_path (handle, TerminateUtf8(str));
		public void TextPath(byte[] utf8)
			=> NativeMethods.cairo_text_path (handle, TerminateUtf8(utf8));
		public TextExtents TextExtents(string s)
		{
			TextExtents extents;
			NativeMethods.cairo_text_extents (handle, TerminateUtf8(s), out extents);
			return extents;
		}
		public void ShowText (ReadOnlySpan<char> s, int tabSize) {
			int size = s.Length * 4 + 1;
			Span<byte> bytes = size > 512 ? new byte[size] : stackalloc byte[size];
			int encodedBytes = s.ToUtf8 (bytes, tabSize);
			bytes[encodedBytes] = 0;
			ShowText (bytes.Slice (0, encodedBytes + 1));
		}
		public TextExtents TextExtents (ReadOnlySpan<char> s, int tabSize) {
			TextExtents (s, tabSize, out TextExtents extents);
			return extents;
		}
		public void TextExtents (ReadOnlySpan<char> s, int tabSize, out TextExtents extents) {
			int size = s.Length * 4 + 1;
			Span<byte> bytes = size > 512 ? new byte[size] : stackalloc byte[size];
			int encodedBytes = s.ToUtf8 (bytes, tabSize);
			bytes[encodedBytes] = 0;
			TextExtents (bytes.Slice (0, encodedBytes + 1), out extents);
		}
		public void ShowText (Span<byte> bytes) {
			NativeMethods.cairo_show_text (handle, ref bytes.GetPinnableReference());
		}
		public void TextExtents (Span<byte> bytes, out TextExtents extents) {
			NativeMethods.cairo_text_extents (handle, ref bytes.GetPinnableReference (), out extents);
		}

		public TextExtents GlyphExtents (Glyph[] glyphs)
		{
			IntPtr ptr = FromGlyphToUnManagedMemory (glyphs);

			TextExtents extents;

			NativeMethods.cairo_glyph_extents (handle, ptr, glyphs.Length, out extents);

			Marshal.FreeHGlobal (ptr);

			return extents;
		}

		public void Flush()
		{
			//throw new NotImplementedException();
		}

		public void Clear()
		{
			throw new NotImplementedException();
		}
		public void MoveTo(Point p)
		{
			throw new NotImplementedException();
		}
		public void LineTo(Point p)
		{
			throw new NotImplementedException();
		}

/*		public void Arc(float xc, float yc, float radius, float a1, float a2)
		{
			throw new NotImplementedException();
		}
		public void ArcNegative(float xc, float yc, float radius, float a1, float a2)
		{
			throw new NotImplementedException();
		}

		public void MoveTo(float x, float y)
		{
			throw new NotImplementedException();
		}

		public void RelMoveTo(float x, float y)
		{
			throw new NotImplementedException();
		}

		public void LineTo(float x, float y)
		{
			throw new NotImplementedException();
		}
		public void RelLineTo(float x, float y)
		{
			throw new NotImplementedException();
		}

		public void CurveTo(float x1, float y1, float x2, float y2, float x3, float y3)
		{
			throw new NotImplementedException();
		}

		public void RelCurveTo(float x1, float y1, float x2, float y2, float x3, float y3)
		{
			throw new NotImplementedException();
		}

		public void Scale(float sx, float sy)
		{
			throw new NotImplementedException();
		}

		public void Translate(float dx, float dy)
		{
			throw new NotImplementedException();
		}
		public void Rotate(float alpha)
		{
			throw new NotImplementedException();
		}
		public void SetSource(float r, float g, float b, float a = 1)
		{
			throw new NotImplementedException();
		}

		public void SetSource(ISurface surf, float x = 0, float y = 0)
		{
			throw new NotImplementedException();
		}

		public void SetSourceSurface(ISurface surf, float x = 0, float y = 0)
		{
			throw new NotImplementedException();
		}
*/
		public void Translate(PointD p)
		{
			throw new NotImplementedException();
		}
		public void RenderSvg(ISvgHandle svg, string subId = null)
			=> svg.Render (this, subId);
		Matrix savedMat;
		public void SaveTransformations()
			=> NativeMethods.cairo_get_matrix (handle, out savedMat);
		public void RestoreTransformations()
			=> NativeMethods.cairo_set_matrix (handle, ref savedMat);
		public void SetSource(IPattern pat) => NativeMethods.cairo_set_source (handle, (pat as Pattern).handle);
		public void SetSource(ISurface surf, double x = 0, double y = 0)
			=> NativeMethods.cairo_set_source_surface (handle, (surf as Surface).handle, x, y);
	}
}