"use strict";

module.exports = function(Chart) {

	var helpers = Chart.helpers;

	Chart.defaults.global.tooltips = {
		enabled: true,
		custom: null,
		mode: 'single',
		backgroundColor: "rgba(0,0,0,0.8)",
		titleFontFamily: Chart.defaults.global.defaultFontFamily,
		titleFontSize: Chart.defaults.global.defaultFontSize,
		titleFontStyle: "bold",
		titleSpacing: 2,
		titleMarginBottom: 6,
		titleColor: "#fff",
		titleAlign: "left",
		bodyFontFamily: Chart.defaults.global.defaultFontFamily,
		bodyFontSize: Chart.defaults.global.defaultFontSize,
		bodyFontStyle: Chart.defaults.global.defaultFontStyle,
		bodySpacing: 2,
		bodyColor: "#fff",
		bodyAlign: "left",
		footerFontFamily: Chart.defaults.global.defaultFontFamily,
		footerFontSize: Chart.defaults.global.defaultFontSize,
		footerFontStyle: "bold",
		footerSpacing: 2,
		footerMarginTop: 6,
		footerColor: "#fff",
		footerAlign: "left",
		yPadding: 6,
		xPadding: 6,
		caretSize: 5,
		cornerRadius: 6,
		multiKeyBackground: '#fff',
		callbacks: {
			// Args are: (tooltipItems, data)
			beforeTitle: helpers.noop,
			title: function(tooltipItems, data) {
				// Pick first xLabel for now
				var title = '';

				if (tooltipItems.length > 0) {
					if (tooltipItems[0].xLabel) {
						title = tooltipItems[0].xLabel;
					} else if (data.labels.length > 0 && tooltipItems[0].index < data.labels.length) {
						title = data.labels[tooltipItems[0].index];
					}
				}

				return title;
			},
			afterTitle: helpers.noop,

			// Args are: (tooltipItems, data)
			beforeBody: helpers.noop,

			// Args are: (tooltipItem, data)
			beforeLabel: helpers.noop,
			label: function(tooltipItem, data) {
				var datasetLabel = data.datasets[tooltipItem.datasetIndex].label || '';
				return datasetLabel + ': ' + tooltipItem.yLabel;
			},
			afterLabel: helpers.noop,

			// Args are: (tooltipItems, data)
			afterBody: helpers.noop,

			// Args are: (tooltipItems, data)
			beforeFooter: helpers.noop,
			footer: helpers.noop,
			afterFooter: helpers.noop
		}
	};

	// Helper to push or concat based on if the 2nd parameter is an array or not
	function pushOrConcat(base, toPush) {
		if (toPush) {
			if (helpers.isArray(toPush)) {
				base = base.concat(toPush);
			} else {
				base.push(toPush);
			}
		}

		return base;
	}

	Chart.Tooltip = Chart.Element.extend({
		initialize: function() {
			var options = this._options;
			helpers.extend(this, {
				_model: {
					// Positioning
					xPadding: options.tooltips.xPadding,
					yPadding: options.tooltips.yPadding,

					// Body
					bodyColor: options.tooltips.bodyColor,
					_bodyFontFamily: options.tooltips.bodyFontFamily,
					_bodyFontStyle: options.tooltips.bodyFontStyle,
					_bodyAlign: options.tooltips.bodyAlign,
					bodyFontSize: options.tooltips.bodyFontSize,
					bodySpacing: options.tooltips.bodySpacing,

					// Title
					titleColor: options.tooltips.titleColor,
					_titleFontFamily: options.tooltips.titleFontFamily,
					_titleFontStyle: options.tooltips.titleFontStyle,
					titleFontSize: options.tooltips.titleFontSize,
					_titleAlign: options.tooltips.titleAlign,
					titleSpacing: options.tooltips.titleSpacing,
					titleMarginBottom: options.tooltips.titleMarginBottom,

					// Footer
					footerColor: options.tooltips.footerColor,
					_footerFontFamily: options.tooltips.footerFontFamily,
					_footerFontStyle: options.tooltips.footerFontStyle,
					footerFontSize: options.tooltips.footerFontSize,
					_footerAlign: options.tooltips.footerAlign,
					footerSpacing: options.tooltips.footerSpacing,
					footerMarginTop: options.tooltips.footerMarginTop,

					// Appearance
					caretSize: options.tooltips.caretSize,
					cornerRadius: options.tooltips.cornerRadius,
					backgroundColor: options.tooltips.backgroundColor,
					opacity: 0,
					legendColorBackground: options.tooltips.multiKeyBackground
				}
			});
		},

		// Get the title
		// Args are: (tooltipItem, data)
		getTitle: function() {
			var beforeTitle = this._options.tooltips.callbacks.beforeTitle.apply(this, arguments),
				title = this._options.tooltips.callbacks.title.apply(this, arguments),
				afterTitle = this._options.tooltips.callbacks.afterTitle.apply(this, arguments);

			var lines = [];
			lines = pushOrConcat(lines, beforeTitle);
			lines = pushOrConcat(lines, title);
			lines = pushOrConcat(lines, afterTitle);

			return lines;
		},

		// Args are: (tooltipItem, data)
		getBeforeBody: function() {
			var lines = this._options.tooltips.callbacks.beforeBody.apply(this, arguments);
			return helpers.isArray(lines) ? lines : lines !== undefined ? [lines] : [];
		},

		// Args are: (tooltipItem, data)
		getBody: function(tooltipItems, data) {
			var lines = [];

			helpers.each(tooltipItems, function(bodyItem) {
				helpers.pushAllIfDefined(this._options.tooltips.callbacks.beforeLabel.call(this, bodyItem, data), lines);
				helpers.pushAllIfDefined(this._options.tooltips.callbacks.label.call(this, bodyItem, data), lines);
				helpers.pushAllIfDefined(this._options.tooltips.callbacks.afterLabel.call(this, bodyItem, data), lines);
			}, this);

			return lines;
		},

		// Args are: (tooltipItem, data)
		getAfterBody: function() {
			var lines = this._options.tooltips.callbacks.afterBody.apply(this, arguments);
			return helpers.isArray(lines) ? lines : lines !== undefined ? [lines] : [];
		},

		// Get the footer and beforeFooter and afterFooter lines
		// Args are: (tooltipItem, data)
		getFooter: function() {
			var beforeFooter = this._options.tooltips.callbacks.beforeFooter.apply(this, arguments);
			var footer = this._options.tooltips.callbacks.footer.apply(this, arguments);
			var afterFooter = this._options.tooltips.callbacks.afterFooter.apply(this, arguments);

			var lines = [];
			lines = pushOrConcat(lines, beforeFooter);
			lines = pushOrConcat(lines, footer);
			lines = pushOrConcat(lines, afterFooter);

			return lines;
		},

		getAveragePosition: function(elements) {

			if (!elements.length) {
				return false;
			}

			var xPositions = [];
			var yPositions = [];

			helpers.each(elements, function(el) {
				if (el) {
					var pos = el.tooltipPosition();
					xPositions.push(pos.x);
					yPositions.push(pos.y);
				}
			});

			var x = 0,
				y = 0;
			for (var i = 0; i < xPositions.length; i++) {
				x += xPositions[i];
				y += yPositions[i];
			}

			return {
				x: Math.round(x / xPositions.length),
				y: Math.round(y / xPositions.length)
			};

		},

		update: function(changed) {
			if (this._active.length) {
				this._model.opacity = 1;

				var element = this._active[0],
					labelColors = [],
					tooltipPosition;

				var tooltipItems = [];

				if (this._options.tooltips.mode === 'single') {
					var yScale = element._yScale || element._scale; // handle radar || polarArea charts
					tooltipItems.push({
						xLabel: element._xScale ? element._xScale.getLabelForIndex(element._index, element._datasetIndex) : '',
						yLabel: yScale ? yScale.getLabelForIndex(element._index, element._datasetIndex) : '',
						index: element._index,
						datasetIndex: element._datasetIndex
					});
					tooltipPosition = this.getAveragePosition(this._active);
				} else {
					helpers.each(this._data.datasets, function(dataset, datasetIndex) {
						if (!helpers.isDatasetVisible(dataset)) {
							return;
						}
						var currentElement = dataset.metaData[element._index];
						if (currentElement) {
							var yScale = element._yScale || element._scale; // handle radar || polarArea charts

							tooltipItems.push({
								xLabel: currentElement._xScale ? currentElement._xScale.getLabelForIndex(currentElement._index, currentElement._datasetIndex) : '',
								yLabel: yScale ? yScale.getLabelForIndex(currentElement._index, currentElement._datasetIndex) : '',
								index: element._index,
								datasetIndex: datasetIndex
							});
						}
					}, null, element._yScale.options.stacked);

					helpers.each(this._active, function(active) {
						if (active) {
							labelColors.push({
								borderColor: active._view.borderColor,
								backgroundColor: active._view.backgroundColor
							});
						}
					}, null, element._yScale.options.stacked);

					tooltipPosition = this.getAveragePosition(this._active);
					tooltipPosition.y = this._active[0]._yScale.getPixelForDecimal(0.5);
				}

				// Build the Text Lines
				helpers.extend(this._model, {
					title: this.getTitle(tooltipItems, this._data),
					beforeBody: this.getBeforeBody(tooltipItems, this._data),
					body: this.getBody(tooltipItems, this._data),
					afterBody: this.getAfterBody(tooltipItems, this._data),
					footer: this.getFooter(tooltipItems, this._data)
				});

				helpers.extend(this._model, {
					x: Math.round(tooltipPosition.x),
					y: Math.round(tooltipPosition.y),
					caretPadding: helpers.getValueOrDefault(tooltipPosition.padding, 2),
					labelColors: labelColors
				});

				// We need to determine alignment of
				var tooltipSize = this.getTooltipSize(this._model);
				this.determineAlignment(tooltipSize); // Smart Tooltip placement to stay on the canvas

				helpers.extend(this._model, this.getBackgroundPoint(this._model, tooltipSize));
			} else {
				this._model.opacity = 0;
			}

			if (changed && this._options.tooltips.custom) {
				this._options.tooltips.custom.call(this, this._model);
			}

			return this;
		},
		getTooltipSize: function getTooltipSize(vm) {
			var ctx = this._chart.ctx;

			var size = {
				height: vm.yPadding * 2, // Tooltip Padding
				width: 0
			};
			var combinedBodyLength = vm.body.length + vm.beforeBody.length + vm.afterBody.length;

			size.height += vm.title.length * vm.titleFontSize; // Title Lines
			size.height += (vm.title.length - 1) * vm.titleSpacing; // Title Line Spacing
			size.height += vm.title.length ? vm.titleMarginBottom : 0; // Title's bottom Margin
			size.height += combinedBodyLength * vm.bodyFontSize; // Body Lines
			size.height += combinedBodyLength ? (combinedBodyLength - 1) * vm.bodySpacing : 0; // Body Line Spacing
			size.height += vm.footer.length ? vm.footerMarginTop : 0; // Footer Margin
			size.height += vm.footer.length * (vm.footerFontSize); // Footer Lines
			size.height += vm.footer.length ? (vm.footer.length - 1) * vm.footerSpacing : 0; // Footer Line Spacing

			// Width
			ctx.font = helpers.fontString(vm.titleFontSize, vm._titleFontStyle, vm._titleFontFamily);
			helpers.each(vm.title, function(line) {
				size.width = Math.max(size.width, ctx.measureText(line).width);
			});

			ctx.font = helpers.fontString(vm.bodyFontSize, vm._bodyFontStyle, vm._bodyFontFamily);
			helpers.each(vm.beforeBody.concat(vm.afterBody), function(line) {
				size.width = Math.max(size.width, ctx.measureText(line).width);
			});
			helpers.each(vm.body, function(line) {
				size.width = Math.max(size.width, ctx.measureText(line).width + (this._options.tooltips.mode !== 'single' ? (vm.bodyFontSize + 2) : 0));
			}, this);

			ctx.font = helpers.fontString(vm.footerFontSize, vm._footerFontStyle, vm._footerFontFamily);
			helpers.each(vm.footer, function(line) {
				size.width = Math.max(size.width, ctx.measureText(line).width);
			});
			size.width += 2 * vm.xPadding;

			return size;
		},
		determineAlignment: function determineAlignment(size) {
			this._model.xAlign = this._model.yAlign = "center";

			if (this._model.y < size.height) {
				this._model.yAlign = 'top';
			} else if (this._model.y > (this._chart.height - size.height)) {
				this._model.yAlign = 'bottom';
			}

			var lf, rf; // functions to determine left, right alignment
			var olf, orf; // functions to determine if left/right alignment causes tooltip to go outside chart
			var yf; // function to get the y alignment if the tooltip goes outside of the left or right edges
			var _this = this;
			var midX = (this._chartInstance.chartArea.left + this._chartInstance.chartArea.right) / 2;
			var midY = (this._chartInstance.chartArea.top + this._chartInstance.chartArea.bottom) / 2;

			if (this._model.yAlign === 'center') {
				lf = function(x) {
					return x <= midX;
				};
				rf = function(x) {
					return x > midX;
				};
			} else {
				lf = function(x) {
					return x <= (size.width / 2);
				};
				rf = function(x) {
					return x >= (_this._chart.width - (size.width / 2));
				};
			}

			olf = function(x) {
				return x + size.width > _this._chart.width;
			};
			orf = function(x) {
				return x - size.width < 0;
			};
			yf = function(y) {
				return y <= midY ? 'top' : 'bottom';
			};

			if (lf(this._model.x)) {
				this._model.xAlign = 'left';

				// Is tooltip too wide and goes over the right side of the chart.?
				if (olf(this._model.x)) {
					this._model.xAlign = 'center';
					this._model.yAlign = yf(this._model.y);
				}
			} else if (rf(this._model.x)) {
				this._model.xAlign = 'right';

				// Is tooltip too wide and goes outside left edge of canvas?
				if (orf(this._model.x)) {
					this._model.xAlign = 'center';
					this._model.yAlign = yf(this._model.y);
				}
			}
		},
		getBackgroundPoint: function getBackgroundPoint(vm, size) {
			// Background Position
			var pt = {
				x: vm.x,
				y: vm.y
			};

			if (vm.xAlign === 'right') {
				pt.x -= size.width;
			} else if (vm.xAlign === 'center') {
				pt.x -= (size.width / 2);
			}

			if (vm.yAlign === 'top') {
				pt.y += vm.caretPadding + vm.caretSize;
			} else if (vm.yAlign === 'bottom') {
				pt.y -= size.height + vm.caretPadding + vm.caretSize;
			} else {
				pt.y -= (size.height / 2);
			}

			if (vm.yAlign === 'center') {
				if (vm.xAlign === 'left') {
					pt.x += vm.caretPadding + vm.caretSize;
				} else if (vm.xAlign === 'right') {
					pt.x -= vm.caretPadding + vm.caretSize;
				}
			} else {
				if (vm.xAlign === 'left') {
					pt.x -= vm.cornerRadius + vm.caretPadding;
				} else if (vm.xAlign === 'right') {
					pt.x += vm.cornerRadius + vm.caretPadding;
				}
			}

			return pt;
		},
		drawCaret: function drawCaret(tooltipPoint, size, opacity, caretPadding) {
			var vm = this._view;
			var ctx = this._chart.ctx;
			var x1, x2, x3;
			var y1, y2, y3;

			if (vm.yAlign === 'center') {
				// Left or right side
				if (vm.xAlign === 'left') {
					x1 = tooltipPoint.x;
					x2 = x1 - vm.caretSize;
					x3 = x1;
				} else {
					x1 = tooltipPoint.x + size.width;
					x2 = x1 + vm.caretSize;
					x3 = x1;
				}

				y2 = tooltipPoint.y + (size.height / 2);
				y1 = y2 - vm.caretSize;
				y3 = y2 + vm.caretSize;
			} else {
				if (vm.xAlign === 'left') {
					x1 = tooltipPoint.x + vm.cornerRadius;
					x2 = x1 + vm.caretSize;
					x3 = x2 + vm.caretSize;
				} else if (vm.xAlign === 'right') {
					x1 = tooltipPoint.x + size.width - vm.cornerRadius;
					x2 = x1 - vm.caretSize;
					x3 = x2 - vm.caretSize;
				} else {
					x2 = tooltipPoint.x + (size.width / 2);
					x1 = x2 - vm.caretSize;
					x3 = x2 + vm.caretSize;
				}

				if (vm.yAlign === 'top') {
					y1 = tooltipPoint.y;
					y2 = y1 - vm.caretSize;
					y3 = y1;
				} else {
					y1 = tooltipPoint.y + size.height;
					y2 = y1 + vm.caretSize;
					y3 = y1;
				}
			}

			var bgColor = helpers.color(vm.backgroundColor);
			ctx.fillStyle = bgColor.alpha(opacity * bgColor.alpha()).rgbString();
			ctx.beginPath();
			ctx.moveTo(x1, y1);
			ctx.lineTo(x2, y2);
			ctx.lineTo(x3, y3);
			ctx.closePath();
			ctx.fill();
		},
		drawTitle: function drawTitle(pt, vm, ctx, opacity) {
			if (vm.title.length) {
				ctx.textAlign = vm._titleAlign;
				ctx.textBaseline = "top";
				
				var titleColor = helpers.color(vm.titleColor);
				ctx.fillStyle = titleColor.alpha(opacity * titleColor.alpha()).rgbString();
				ctx.font = helpers.fontString(vm.titleFontSize, vm._titleFontStyle, vm._titleFontFamily);

				helpers.each(vm.title, function(title, i) {
					ctx.fillText(title, pt.x, pt.y);
					pt.y += vm.titleFontSize + vm.titleSpacing; // Line Height and spacing

					if (i + 1 === vm.title.length) {
						pt.y += vm.titleMarginBottom - vm.titleSpacing; // If Last, add margin, remove spacing
					}
				});
			}
		},
		drawBody: function drawBody(pt, vm, ctx, opacity) {
			ctx.textAlign = vm._bodyAlign;
			ctx.textBaseline = "top";

			var bodyColor = helpers.color(vm.bodyColor);
			ctx.fillStyle = bodyColor.alpha(opacity * bodyColor.alpha()).rgbString();
			ctx.font = helpers.fontString(vm.bodyFontSize, vm._bodyFontStyle, vm._bodyFontFamily);

			// Before Body
			helpers.each(vm.beforeBody, function(beforeBody) {
				ctx.fillText(beforeBody, pt.x, pt.y);
				pt.y += vm.bodyFontSize + vm.bodySpacing;
			});

			helpers.each(vm.body, function(body, i) {
				// Draw Legend-like boxes if needed
				if (this._options.tooltips.mode !== 'single') {
					// Fill a white rect so that colours merge nicely if the opacity is < 1
					ctx.fillStyle = helpers.color(vm.legendColorBackground).alpha(opacity).rgbaString();
					ctx.fillRect(pt.x, pt.y, vm.bodyFontSize, vm.bodyFontSize);

					// Border
					ctx.strokeStyle = helpers.color(vm.labelColors[i].borderColor).alpha(opacity).rgbaString();
					ctx.strokeRect(pt.x, pt.y, vm.bodyFontSize, vm.bodyFontSize);

					// Inner square
					ctx.fillStyle = helpers.color(vm.labelColors[i].backgroundColor).alpha(opacity).rgbaString();
					ctx.fillRect(pt.x + 1, pt.y + 1, vm.bodyFontSize - 2, vm.bodyFontSize - 2);

					ctx.fillStyle = helpers.color(vm.bodyColor).alpha(opacity).rgbaString(); // Return fill style for text
				}

				// Body Line
				ctx.fillText(body, pt.x + (this._options.tooltips.mode !== 'single' ? (vm.bodyFontSize + 2) : 0), pt.y);

				pt.y += vm.bodyFontSize + vm.bodySpacing;
			}, this);

			// After Body
			helpers.each(vm.afterBody, function(afterBody) {
				ctx.fillText(afterBody, pt.x, pt.y);
				pt.y += vm.bodyFontSize;
			});

			pt.y -= vm.bodySpacing; // Remove last body spacing
		},
		drawFooter: function drawFooter(pt, vm, ctx, opacity) {
			if (vm.footer.length) {
				pt.y += vm.footerMarginTop;

				ctx.textAlign = vm._footerAlign;
				ctx.textBaseline = "top";
				
				var footerColor = helpers.color(vm.footerColor);
				ctx.fillStyle = footerColor.alpha(opacity * footerColor.alpha()).rgbString();
				ctx.font = helpers.fontString(vm.footerFontSize, vm._footerFontStyle, vm._footerFontFamily);

				helpers.each(vm.footer, function(footer) {
					ctx.fillText(footer, pt.x, pt.y);
					pt.y += vm.footerFontSize + vm.footerSpacing;
				});
			}
		},
		draw: function draw() {
			var ctx = this._chart.ctx;
			var vm = this._view;

			if (vm.opacity === 0) {
				return;
			}

			var caretPadding = vm.caretPadding;
			var tooltipSize = this.getTooltipSize(vm);
			var pt = {
				x: vm.x,
				y: vm.y
			};

			// IE11/Edge does not like very small opacities, so snap to 0
			var opacity = Math.abs(vm.opacity < 1e-3) ? 0 : vm.opacity;

			if (this._options.tooltips.enabled) {
				// Draw Background
				var bgColor = helpers.color(vm.backgroundColor);
				ctx.fillStyle = bgColor.alpha(opacity * bgColor.alpha()).rgbString();
				helpers.drawRoundedRectangle(ctx, pt.x, pt.y, tooltipSize.width, tooltipSize.height, vm.cornerRadius);
				ctx.fill();

				// Draw Caret
				this.drawCaret(pt, tooltipSize, opacity, caretPadding);

				// Draw Title, Body, and Footer
				pt.x += vm.xPadding;
				pt.y += vm.yPadding;

				// Titles
				this.drawTitle(pt, vm, ctx, opacity);

				// Body
				this.drawBody(pt, vm, ctx, opacity);

				// Footer
				this.drawFooter(pt, vm, ctx, opacity);
			}
		}
	});
};