namespace CairoChart {

	public class Cursors {

		public List<Point?> list = new List<Point?> ();
		public Point active_cursor = Point(); // { get; protected set; default = Point128 (); }
		public bool is_cursor_active = false; // { get; protected set; default = false; }
		public Cursors.Style cursor_style = Cursors.Style();
		public Cursors.CursorCrossings[] cursors_crossings = {};
		protected Chart chart = null;

		public Cursors (Chart chart) {
			this.chart = chart;
		}

		public Cursors copy () {
			var c = new Cursors (chart);
			c.list = list.copy();
			c.active_cursor = active_cursor;
			c.is_cursor_active = is_cursor_active;
			c.cursor_style = cursor_style;
			c.cursors_crossings = cursors_crossings;
			return c;
		}

		public enum Orientation {
			VERTICAL = 0,  // default
			HORIZONTAL
		}

		public struct Style {

			public Orientation orientation;
			public double select_distance;
			public Line.Style line_style;

			public Style () {
				orientation = Orientation.VERTICAL;
				select_distance = 32;
				line_style = Line.Style(Color(0.2, 0.2, 0.2, 0.8));
			}
		}

		protected struct CursorCross {
			uint series_index;
			Point128 point;
			Point128 size;
			bool show_x;
			bool show_date;
			bool show_time;
			bool show_y;
			Point scr_point;
			Point scr_value_point;
		}
		protected struct CursorCrossings {
			uint cursor_index;
			CursorCross[] crossings;
		}

		public virtual void set_active_cursor (Point p, bool remove = false) {
			active_cursor.x = chart.zoom.x + (p.x - chart.plarea.x) / chart.plarea.width * chart.zoom.width;
			active_cursor.y = chart.zoom.y + chart.zoom.height - (chart.plarea.y + chart.plarea.height - p.y) / chart.plarea.height * chart.zoom.height;
			is_cursor_active = ! remove;
		}

		public virtual void add_active_cursor () {
			list.append (active_cursor);
			is_cursor_active = false;
		}

		public virtual Float128 rel2scr_x(Float128 x) {
			return chart.plarea.x + chart.plarea.width * (x - chart.zoom.x) / chart.zoom.width;
		}

		public virtual Float128 rel2scr_y(Float128 y) {
			return chart.plarea.y + chart.plarea.height * (y - chart.zoom.y) / chart.zoom.height;
		}

		public virtual void remove_active_cursor () {
			if (list.length() == 0) return;
			var distance = 1024.0 * 1024.0;//width * width;
			uint rm_indx = 0;
			uint i = 0;
			foreach (var c in list) {
				double d = distance;
				switch (cursor_style.orientation) {
				case Cursors.Orientation.VERTICAL:
					d = (rel2scr_x(c.x) - rel2scr_x(active_cursor.x)).abs();
					break;
				case Cursors.Orientation.HORIZONTAL:
					d = (rel2scr_y(c.y) - rel2scr_y(active_cursor.y)).abs();
					break;
				}
				if (d < distance) {
					distance = d;
					rm_indx = i;
				}
				++i;
			}
			if (distance < cursor_style.select_distance)
				list.delete_link(list.nth(rm_indx));
			is_cursor_active = false;
		}

		protected List<Point?> get_all_cursors () {
			var all_cursors = list.copy_deep ((src) => { return src; });
			if (is_cursor_active)
				all_cursors.append(active_cursor);
			return all_cursors;
		}

		public void get_cursors_crossings () {
			var all_cursors = get_all_cursors();

			CursorCrossings[] local_cursor_crossings = {};

			for (var ci = 0, max_ci = all_cursors.length(); ci < max_ci; ++ci) {
				var c = all_cursors.nth_data(ci);
				switch (cursor_style.orientation) {
				case Orientation.VERTICAL:
					if (c.x <= chart.zoom.x || c.x >= chart.zoom.x + chart.zoom.width) continue; break;
				case Orientation.HORIZONTAL:
					if (c.y <= chart.zoom.y || c.y >= chart.zoom.y + chart.zoom.height) continue; break;
				}

				CursorCross[] crossings = {};
				for (var si = 0, max_si = chart.series.length; si < max_si; ++si) {
					var s = chart.series[si];
					if (!s.zoom_show) continue;

					Point128[] points = {};
					switch (cursor_style.orientation) {
					case Orientation.VERTICAL:
						points = Math.sort_points (s, s.sort);
						break;
					case Orientation.HORIZONTAL:
						points = Math.sort_points (s, s.sort);
						break;
					}

					for (var i = 0; i + 1 < points.length; ++i) {
						switch (cursor_style.orientation) {
						case Orientation.VERTICAL:
							Float128 y = 0.0;
							if (Math.vcross(s.get_scr_point(points[i]), s.get_scr_point(points[i+1]), rel2scr_x(c.x),
							                chart.plarea.y, chart.plarea.y + chart.plarea.height, out y)) {
								var point = Point128(s.get_real_x(rel2scr_x(c.x)), s.get_real_y(y));
								Point128 size; bool show_x, show_date, show_time, show_y;
								cross_what_to_show(s, out show_x, out show_time, out show_date, out show_y);
								calc_cross_sizes (s, point, out size, show_x, show_time, show_date, show_y);
								CursorCross cc = {si, point, size, show_x, show_date, show_time, show_y};
								crossings += cc;
							}
							break;
						case Orientation.HORIZONTAL:
							Float128 x = 0.0;
							if (Math.hcross(s.get_scr_point(points[i]), s.get_scr_point(points[i+1]),
							                chart.plarea.x, chart.plarea.x + chart.plarea.width, rel2scr_y(c.y), out x)) {
								var point = Point128(s.get_real_x(x), s.get_real_y(rel2scr_y(c.y)));
								Point128 size; bool show_x, show_date, show_time, show_y;
								cross_what_to_show(s, out show_x, out show_time, out show_date, out show_y);
								calc_cross_sizes (s, point, out size, show_x, show_time, show_date, show_y);
								CursorCross cc = {si, point, size, show_x, show_date, show_time, show_y};
								crossings += cc;
							}
							break;
						}
					}
				}
				if (crossings.length != 0) {
					CursorCrossings ccs = {ci, crossings};
					local_cursor_crossings += ccs;
				}
			}
			cursors_crossings = local_cursor_crossings;
		}

		protected virtual void calc_cursors_value_positions () {
			for (var ccsi = 0, max_ccsi = cursors_crossings.length; ccsi < max_ccsi; ++ccsi) {
				for (var cci = 0, max_cci = cursors_crossings[ccsi].crossings.length; cci < max_cci; ++cci) {
					// TODO: Ticket #142: find smart algorithm of cursors values placements
					unowned CursorCross[] cr = cursors_crossings[ccsi].crossings;
					cr[cci].scr_point = chart.series[cr[cci].series_index].get_scr_point (cr[cci].point);
					var d_max = double.max (cr[cci].size.x / 1.5, cr[cci].size.y / 1.5);
					cr[cci].scr_value_point = Point (cr[cci].scr_point.x + d_max, cr[cci].scr_point.y - d_max);
				}
			}
		}

		protected virtual void cross_what_to_show (Series s, out bool show_x, out bool show_time,
		                                                     out bool show_date, out bool show_y) {
			show_x = show_time = show_date = show_y = false;
			switch (cursor_style.orientation) {
			case Orientation.VERTICAL:
				show_y = true;
				if (!chart.joint_x)
					switch (s.axis_x.type) {
					case Axis.Type.NUMBERS: show_x = true; break;
					case Axis.Type.DATE_TIME:
						if (s.axis_x.date_format != "") show_date = true;
						if (s.axis_x.time_format != "") show_time = true;
						break;
					}
				break;
			case Orientation.HORIZONTAL:
				if (!chart.joint_y) show_y = true;
				switch (s.axis_x.type) {
				case Axis.Type.NUMBERS: show_x = true; break;
				case Axis.Type.DATE_TIME:
					if (s.axis_x.date_format != "") show_date = true;
					if (s.axis_x.time_format != "") show_time = true;
					break;
				}
				break;
			}
		}

		protected virtual void calc_cross_sizes (Series s, Point128 p, out Point128 size,
		                                         bool show_x = false, bool show_time = false,
		                                         bool show_date = false, bool show_y = false) {
			if (show_x == show_time == show_date == show_y == false)
				cross_what_to_show(s, out show_x, out show_time, out show_date, out show_y);
			size = Point128 ();
			string date, time;
			s.axis_x.format_date_time(p.x, out date, out time);
			var date_t = new Text (date, s.axis_x.font_style, s.axis_x.color);
			var time_t = new Text (time, s.axis_x.font_style, s.axis_x.color);
			var x_t = new Text (s.axis_x.format.printf((LongDouble)p.x), s.axis_x.font_style, s.axis_x.color);
			var y_t = new Text (s.axis_y.format.printf((LongDouble)p.y), s.axis_y.font_style, s.axis_y.color);
			double h_x = 0.0, h_y = 0.0;
			if (show_x) { var sz = x_t.get_size(chart.ctx); size.x = sz.width; h_x = sz.height; }
			if (show_date) { var sz = date_t.get_size(chart.ctx); size.x = sz.width; h_x = sz.height; }
			if (show_time) { var sz = time_t.get_size(chart.ctx); size.x = double.max(size.x, sz.width); h_x += sz.height; }
			if (show_y) { var sz = y_t.get_size(chart.ctx); size.x += sz.width; h_y = sz.height; }
			if ((show_x || show_date || show_time) && show_y) size.x += double.max(s.axis_x.font_spacing, s.axis_y.font_spacing);
			if (show_date && show_time) h_x += s.axis_x.font_spacing;
			size.y = double.max (h_x, h_y);
		}

		public virtual void draw_cursors () {
			if (chart.series.length == 0) return;

			var all_cursors = get_all_cursors();
			calc_cursors_value_positions();

			for (var cci = 0, max_cci = cursors_crossings.length; cci < max_cci; ++cci) {
				var low = Point128(chart.plarea.x + chart.plarea.width, chart.plarea.y + chart.plarea.height);  // low and high
				var high = Point128(chart.plarea.x, chart.plarea.y); //              points of the cursor
				unowned CursorCross[] ccs = cursors_crossings[cci].crossings;
				cursor_style.line_style.set(chart);
				for (var ci = 0, max_ci = ccs.length; ci < max_ci; ++ci) {
					var si = ccs[ci].series_index;
					var s = chart.series[si];
					var p = ccs[ci].point;
					var scrx = s.get_scr_x(p.x);
					var scry = s.get_scr_y(p.y);
					if (scrx < low.x) low.x = scrx;
					if (scry < low.y) low.y = scry;
					if (scrx > high.x) high.x = scrx;
					if (scry > high.y) high.y = scry;

					if (chart.joint_x) {
						switch (s.axis_x.position) {
						case Axis.Position.LOW: high.y = chart.plarea.y + chart.plarea.height + s.axis_x.font_spacing; break;
						case Axis.Position.HIGH: low.y = chart.plarea.y - s.axis_x.font_spacing; break;
						case Axis.Position.BOTH:
							high.y = chart.plarea.y + chart.plarea.height + s.axis_x.font_spacing;
							low.y = chart.plarea.y - s.axis_x.font_spacing;
							break;
						}
					}
					if (chart.joint_y) {
						switch (s.axis_y.position) {
						case Axis.Position.LOW: low.x = chart.plarea.x - s.axis_y.font_spacing; break;
						case Axis.Position.HIGH: high.x = chart.plarea.x + chart.plarea.width + s.axis_y.font_spacing; break;
						case Axis.Position.BOTH:
							low.x = chart.plarea.x - s.axis_y.font_spacing;
							high.x = chart.plarea.x + chart.plarea.width + s.axis_y.font_spacing;
							break;
						}
					}

					chart.ctx.move_to (ccs[ci].scr_point.x, ccs[ci].scr_point.y);
					chart.ctx.line_to (ccs[ci].scr_value_point.x, ccs[ci].scr_value_point.y);
				}

				var c = all_cursors.nth_data(cursors_crossings[cci].cursor_index);

				switch (cursor_style.orientation) {
				case Orientation.VERTICAL:
					if (low.y > high.y) continue;
					chart.ctx.move_to (rel2scr_x(c.x), low.y);
					chart.ctx.line_to (rel2scr_x(c.x), high.y);

					// show joint X value
					if (chart.joint_x) {
						var s = chart.series[chart.zoom_1st_idx];
						var x = s.get_real_x(rel2scr_x(c.x));
						string text = "", time_text = "";
						switch (s.axis_x.type) {
						case Axis.Type.NUMBERS:
							text = s.axis_x.format.printf((LongDouble)x);
							break;
						case Axis.Type.DATE_TIME:
							s.axis_x.format_date_time(x, out text, out time_text);
							break;
						default:
							break;
						}
						var text_t = new Text(text, s.axis_x.font_style, s.axis_x.color);
						var sz = text_t.get_size(chart.ctx);
						var time_text_t = new Text(time_text, s.axis_x.font_style, s.axis_x.color);
						var print_y = 0.0;
						switch (s.axis_x.position) {
							case Axis.Position.LOW: print_y = chart.area.y + chart.area.height - s.axis_x.font_spacing
								                    - (chart.legend.position == Legend.Position.BOTTOM ? chart.legend.height : 0);
								break;
							case Axis.Position.HIGH:
								var title_height = chart.title.get_height(chart.ctx) + (chart.legend.position == Legend.Position.TOP ?
								                   chart.title_spacing * 2 : chart.title_spacing);
								print_y = chart.area.y + title_height + s.axis_x.font_spacing
								          + (chart.legend.position == Legend.Position.TOP ? chart.legend.height : 0);
								switch (s.axis_x.type) {
								case Axis.Type.NUMBERS:
									print_y += sz.height;
									break;
								case Axis.Type.DATE_TIME:
									print_y += (s.axis_x.date_format == "" ? 0 : sz.height)
									           + (s.axis_x.time_format == "" ? 0 : time_text_t.get_height(chart.ctx))
									           + (s.axis_x.date_format == "" || s.axis_x.time_format == "" ? 0 : s.axis_x.font_spacing);
									break;
								}
								break;
						}
						var print_x = s.compact_rec_x_pos (x, text_t);
						chart.ctx.move_to (print_x, print_y);

						switch (s.axis_x.type) {
						case Axis.Type.NUMBERS:
							text_t.show(chart.ctx);
							break;
						case Axis.Type.DATE_TIME:
							if (s.axis_x.date_format != "") text_t.show(chart.ctx);
							print_x = s.compact_rec_x_pos (x, time_text_t);
							chart.ctx.move_to (print_x, print_y - (s.axis_x.date_format == "" ? 0 : sz.height + s.axis_x.font_spacing));
							if (s.axis_x.time_format != "") time_text_t.show(chart.ctx);
							break;
						}
					}
					break;
				case Orientation.HORIZONTAL:
					if (low.x > high.x) continue;
					chart.ctx.move_to (low.x, rel2scr_y(c.y));
					chart.ctx.line_to (high.x, rel2scr_y(c.y));

					// show joint Y value
					if (chart.joint_y) {
						var s = chart.series[chart.zoom_1st_idx];
						var y = s.get_real_y(rel2scr_y(c.y));
						var text_t = new Text(s.axis_y.format.printf((LongDouble)y, s.axis_y.font_style));
						var print_y = s.compact_rec_y_pos (y, text_t);
						var print_x = 0.0;
						switch (s.axis_y.position) {
						case Axis.Position.LOW:
							print_x = chart.area.x + s.axis_y.font_spacing
							          + (chart.legend.position == Legend.Position.LEFT ? chart.legend.width : 0);
							break;
						case Axis.Position.HIGH:
							print_x = chart.area.x + chart.area.width - text_t.get_width(chart.ctx) - s.axis_y.font_spacing
							          - (chart.legend.position == Legend.Position.RIGHT ? chart.legend.width : 0);
							break;
						}
						chart.ctx.move_to (print_x, print_y);
						text_t.show(chart.ctx);
					}
					break;
				}
				chart.ctx.stroke ();

				// show value (X, Y or [X;Y])
				for (var ci = 0, max_ci = ccs.length; ci < max_ci; ++ci) {
					var si = ccs[ci].series_index;
					var s = chart.series[si];
					var point = ccs[ci].point;
					var size = ccs[ci].size;
					var svp = ccs[ci].scr_value_point;
					var show_x = ccs[ci].show_x;
					var show_date = ccs[ci].show_date;
					var show_time = ccs[ci].show_time;
					var show_y = ccs[ci].show_y;

					chart.color = chart.bg_color;
					chart.ctx.rectangle (svp.x - size.x / 2, svp.y - size.y / 2, size.x, size.y);
					chart.ctx.fill();

					if (show_x) {
						chart.color = s.axis_x.color;
						var text_t = new Text(s.axis_x.format.printf((LongDouble)point.x), s.axis_x.font_style);
						chart.ctx.move_to (svp.x - size.x / 2, svp.y + text_t.get_height(chart.ctx) / 2);
						if (chart.joint_x) chart.color = chart.joint_color;
						text_t.show(chart.ctx);
					}

					if (show_time) {
						chart.color = s.axis_x.color;
						string date = "", time = "";
						s.axis_x.format_date_time(point.x, out date, out time);
						var text_t = new Text(time, s.axis_x.font_style);
						var sz = text_t.get_size(chart.ctx);
						var y = svp.y + sz.height / 2;
						if (show_date) y -= sz.height / 2 + s.axis_x.font_spacing / 2;
						chart.ctx.move_to (svp.x - size.x / 2, y);
						if (chart.joint_x) chart.color = chart.joint_color;
						text_t.show(chart.ctx);
					}

					if (show_date) {
						chart.color = s.axis_x.color;
						string date = "", time = "";
						s.axis_x.format_date_time(point.x, out date, out time);
						var text_t = new Text(date, s.axis_x.font_style);
						var sz = text_t.get_size(chart.ctx);
						var y = svp.y + sz.height / 2;
						if (show_time) y += sz.height / 2 + s.axis_x.font_spacing / 2;
						chart.ctx.move_to (svp.x - size.x / 2, y);
						if (chart.joint_x) chart.color = chart.joint_color;
						text_t.show(chart.ctx);
					}

					if (show_y) {
						chart.color = s.axis_y.color;
						var text_t = new Text(s.axis_y.format.printf((LongDouble)point.y), s.axis_y.font_style);
						var sz = text_t.get_size(chart.ctx);
						chart.ctx.move_to (svp.x + size.x / 2 - sz.width, svp.y + sz.height / 2);
						if (chart.joint_y) chart.color = chart.joint_color;
						text_t.show(chart.ctx);
					}
				}
			}
		}

		public bool get_cursors_delta (out Float128 delta) {
			delta = 0.0;
			if (chart.series.length == 0) return false;
			if (list.length() + (is_cursor_active ? 1 : 0) != 2) return false;
			if (chart.joint_x && cursor_style.orientation == Orientation.VERTICAL) {
				Float128 val1 = chart.series[chart.zoom_1st_idx].get_real_x(rel2scr_x(list.nth_data(0).x));
				Float128 val2 = 0;
				if (is_cursor_active)
					val2 = chart.series[chart.zoom_1st_idx].get_real_x(rel2scr_x(active_cursor.x));
				else
					val2 = chart.series[chart.zoom_1st_idx].get_real_x(rel2scr_x(list.nth_data(1).x));
				if (val2 > val1)
					delta = val2 - val1;
				else
					delta = val1 - val2;
				return true;
			}
			if (chart.joint_y && cursor_style.orientation == Orientation.HORIZONTAL) {
				Float128 val1 = chart.series[chart.zoom_1st_idx].get_real_y(rel2scr_y(list.nth_data(0).y));
				Float128 val2 = 0;
				if (is_cursor_active)
					val2 = chart.series[chart.zoom_1st_idx].get_real_y(rel2scr_y(active_cursor.y));
				else
					val2 = chart.series[chart.zoom_1st_idx].get_real_y(rel2scr_y(list.nth_data(1).y));
				if (val2 > val1)
					delta = val2 - val1;
				else
					delta = val1 - val2;
				return true;
			}
			return false;
		}

		public string get_cursors_delta_str () {
			Float128 delta = 0.0;
			if (!get_cursors_delta(out delta)) return "";
			var str = "";
			var s = chart.series[chart.zoom_1st_idx];
			if (chart.joint_x)
				switch (s.axis_x.type) {
				case Axis.Type.NUMBERS:
					str = s.axis_x.format.printf((LongDouble)delta);
					break;
				case Axis.Type.DATE_TIME:
					var date = "", time = "";
					int64 days = (int64)(delta / 24 / 3600);
					s.axis_x.format_date_time(delta, out date, out time);
					str = days.to_string() + " + " + time;
					break;
				}
			if (chart.joint_y) {
				str = s.axis_y.format.printf((LongDouble)delta);
			}
			return str;
		}
	}
}