/*****************************************************************************
 * Open MCT, Copyright (c) 2014-2018, United States Government
 * as represented by the Administrator of the National Aeronautics and Space
 * Administration. All rights reserved.
 *
 * Open MCT is licensed under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0.
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 * Open MCT includes source code licensed under additional open source
 * licenses. See the Open Source Licenses file (LICENSES.md) included with
 * this source code distribution or the Licensing information page available
 * at runtime from the About dialog for additional information.
 *****************************************************************************/

<template>
    <div class="l-layout__frame c-frame no-frame"
         :style="style">
        <svg width="100%" height="100%">
            <line v-bind="linePosition"
                  :stroke="item.stroke"
                  stroke-width="2">
            </line>
        </svg>

        <div class="c-frame-edit__move"
             @mousedown="startDrag($event)"></div>
        <div class="c-frame-edit" v-if="showFrameEdit">
            <div class="c-frame-edit__handle"
                 :class="startHandleClass"
                 @mousedown="startDrag($event, 'start')"></div>
            <div class="c-frame-edit__handle"
                 :class="endHandleClass"
                 @mousedown="startDrag($event, 'end')"></div>
        </div>
    </div>
</template>

 <script>

    const START_HANDLE_QUADRANTS = {
        1: 'c-frame-edit__handle--sw',
        2: 'c-frame-edit__handle--se',
        3: 'c-frame-edit__handle--ne',
        4: 'c-frame-edit__handle--nw'
    };

    const END_HANDLE_QUADRANTS = {
        1: 'c-frame-edit__handle--ne',
        2: 'c-frame-edit__handle--nw',
        3: 'c-frame-edit__handle--sw',
        4: 'c-frame-edit__handle--se'
    };

    export default {
        makeDefinition() {
            return {
                x: 5,
                y: 10,
                x2: 10,
                y2: 5,
                stroke: '#717171'
            };
        },
        inject: ['openmct'],
        props: {
            item: Object,
            gridSize: Array,
            initSelect: Boolean,
            index: Number,
            multiSelect: Boolean
        },
        data() {
            return {
                dragPosition: undefined,
                dragging: undefined,
                selection: []
            };
        },
        computed: {
            showFrameEdit() {
                let layoutItem = this.selection.length > 0 && this.selection[0][0].context.layoutItem;
                return !this.multiSelect && layoutItem && layoutItem.id === this.item.id;
            },
            position() {
                let {x, y, x2, y2} = this.item;
                if (this.dragging && this.dragPosition) {
                    ({x, y, x2, y2} = this.dragPosition);
                }
                return {x, y, x2, y2};
            },
            style() {
                let {x, y, x2, y2} = this.position;
                let width = Math.max(this.gridSize[0] * Math.abs(x - x2), 1);
                let height = Math.max(this.gridSize[1] * Math.abs(y - y2), 1);
                let left = this.gridSize[0] * Math.min(x, x2);
                let top = this.gridSize[1] * Math.min(y, y2);
                return {
                    left: `${left}px`,
                    top: `${top}px`,
                    width: `${width}px`,
                    height: `${height}px`,
                };
            },
            startHandleClass() {
                return START_HANDLE_QUADRANTS[this.vectorQuadrant];
            },
            endHandleClass() {
                return END_HANDLE_QUADRANTS[this.vectorQuadrant];
            },
            vectorQuadrant() {
                let {x, y, x2, y2} = this.position;
                if (x2 > x) {
                    if (y2 < y) {
                        return 1;
                    }
                    return 4;
                }
                if (y2 < y) {
                    return 2;
                }
                return 3;
            },
            linePosition() {
                if (this.vectorQuadrant === 1) {
                    return {
                        x1: '0%',
                        y1: '100%',
                        x2: '100%',
                        y2: '0%'
                    };
                }
                if (this.vectorQuadrant === 4) {
                    return {
                        x1: '0%',
                        y1: '0%',
                        x2: '100%',
                        y2: '100%'
                    };
                }
                if (this.vectorQuadrant === 2) {
                    return {
                        x1: '0%',
                        y1: '0%',
                        x2: '100%',
                        y2: '100%'
                    };
                }
                if (this.vectorQuadrant === 3) {
                    return {
                        x1: '100%',
                        y1: '0%',
                        x2: '0%',
                        y2: '100%'
                    };
                }
            }
        },
        methods: {
            startDrag(event, position) {
                this.dragging = position;
                document.body.addEventListener('mousemove', this.continueDrag);
                document.body.addEventListener('mouseup', this.endDrag);
                this.startPosition = [event.pageX, event.pageY];
                this.dragPosition = {
                    x: this.item.x,
                    y: this.item.y,
                    x2: this.item.x2,
                    y2: this.item.y2
                };
                event.preventDefault();
            },
            continueDrag(event) {
                event.preventDefault();
                let pxDeltaX = this.startPosition[0] - event.pageX;
                let pxDeltaY = this.startPosition[1] - event.pageY;
                let newPosition = this.calculateDragPosition(pxDeltaX, pxDeltaY);

                if (!this.dragging) {
                    if (!_.isEqual(newPosition, this.dragPosition)) {
                        let gridDelta = [event.pageX - this.startPosition[0], event.pageY - this.startPosition[1]];
                        this.dragPosition = newPosition;
                        this.$emit('move', this.toGridDelta(gridDelta));
                    }
                } else {
                    this.dragPosition = newPosition;
                }
            },
            endDrag(event) {
                document.body.removeEventListener('mousemove', this.continueDrag);
                document.body.removeEventListener('mouseup', this.endDrag);
                let {x, y, x2, y2} = this.dragPosition;
                if (!this.dragging) {
                    this.$emit('endMove');
                } else {
                    this.$emit('endLineResize', this.item, {x, y, x2, y2});
                }
                this.dragPosition = undefined;
                this.dragging = undefined;
                event.preventDefault();
            },
            calculateDragPosition(pxDeltaX, pxDeltaY) {
                let gridDeltaX = Math.round(pxDeltaX / this.gridSize[0]);
                let gridDeltaY = Math.round(pxDeltaY / this.gridSize[0]); // TODO: should this be gridSize[1]?
                let {x, y, x2, y2} = this.item;
                let dragPosition = {x, y, x2, y2};

                if (this.dragging === 'start') {
                    dragPosition.x -= gridDeltaX;
                    dragPosition.y -= gridDeltaY;
                } else if (this.dragging === 'end') {
                    dragPosition.x2 -= gridDeltaX;
                    dragPosition.y2 -= gridDeltaY;
                } else {
                    // dragging entire line.
                    dragPosition.x -= gridDeltaX;
                    dragPosition.y -= gridDeltaY;
                    dragPosition.x2 -= gridDeltaX;
                    dragPosition.y2 -= gridDeltaY;
                }
                return dragPosition;
            },
            setSelection(selection) {
                this.selection = selection;
            },
            toGridDelta(pixelDelta) {
                return pixelDelta.map((v, i) => {
                    return Math.round(v / this.gridSize[i]);
                });
            }
        },
        watch: {
            index(newIndex) {
                if (!this.context) {
                    return;
                }

                this.context.index = newIndex;
            }
        },
        mounted() {
            this.openmct.selection.on('change', this.setSelection);
            this.context = {
                layoutItem: this.item,
                index: this.index
            };
            this.removeSelectable = this.openmct.selection.selectable(
                this.$el, this.context, this.initSelect);
        },
        destroyed() {
            if (this.removeSelectable) {
                this.removeSelectable();
            }
            this.openmct.selection.off('change', this.setSelection);
        }
    }
 </script>
