import React from "react";

import { drag as d3Drag } from "d3-drag";
import { forceLink as d3ForceLink } from "d3-force";
import { select as d3Select, selectAll as d3SelectAll, event as d3Event } from "d3-selection";
import { zoom as d3Zoom } from "d3-zoom";

import CONST from "./graph.const";
import DEFAULT_CONFIG from "./graph.config";
import ERRORS from "../../err";

import * as collapseHelper from "./collapse.helper";
import * as graphHelper from "./graph.helper";
import * as graphRenderer from "./graph.renderer";
import utils from "../../utils";

/**
 * Graph component is the main component for react-d3-graph components, its interface allows its user
 * to build the graph once the user provides the data, configuration (optional) and callback interactions (also optional).
 * The code for the [live example](https://danielcaldas.github.io/react-d3-graph/sandbox/index.html)
 * can be consulted [here](https://github.com/danielcaldas/react-d3-graph/blob/master/sandbox/Sandbox.jsx)
 * @example
 * import { Graph } from 'react-d3-graph';
 *
 * // graph payload (with minimalist structure)
 * const data = {
 *     nodes: [
 *       {id: 'Harry'},
 *       {id: 'Sally'},
 *       {id: 'Alice'}
 *     ],
 *     links: [
 *         {source: 'Harry', target: 'Sally'},
 *         {source: 'Harry', target: 'Alice'},
 *     ]
 * };
 *
 * // the graph configuration, you only need to pass down properties
 * // that you want to override, otherwise default ones will be used
 * const myConfig = {
 *     nodeHighlightBehavior: true,
 *     node: {
 *         color: 'lightgreen',
 *         size: 120,
 *         highlightStrokeColor: 'blue'
 *     },
 *     link: {
 *         highlightColor: 'lightblue'
 *     }
 * };
 *
 * // graph event callbacks
 * const onClickGraph = function() {
 *      window.alert('Clicked the graph background');
 * };
 *
 * const onClickNode = function(nodeId) {
 *      window.alert('Clicked node ${nodeId}');
 * };
 *
 * const onDoubleClickNode = function(nodeId) {
 *      window.alert('Double clicked node ${nodeId}');
 * };
 *
 * const onRightClickNode = function(event, nodeId) {
 *      window.alert('Right clicked node ${nodeId}');
 * };
 *
 * const onMouseOverNode = function(nodeId) {
 *      window.alert(`Mouse over node ${nodeId}`);
 * };
 *
 * const onMouseOutNode = function(nodeId) {
 *      window.alert(`Mouse out node ${nodeId}`);
 * };
 *
 * const onClickLink = function(source, target) {
 *      window.alert(`Clicked link between ${source} and ${target}`);
 * };
 *
 * const onRightClickLink = function(event, source, target) {
 *      window.alert('Right clicked link between ${source} and ${target}');
 * };
 *
 * const onMouseOverLink = function(source, target) {
 *      window.alert(`Mouse over in link between ${source} and ${target}`);
 * };
 *
 * const onMouseOutLink = function(source, target) {
 *      window.alert(`Mouse out link between ${source} and ${target}`);
 * };
 *
 * <Graph
 *      id='graph-id' // id is mandatory, if no id is defined rd3g will throw an error
 *      data={data}
 *      config={myConfig}
 *      onClickGraph={onClickGraph}
 *      onClickNode={onClickNode}
 *      onDoubleClickNode={onDoubleClickNode}
 *      onRightClickNode={onRightClickNode}
 *      onClickLink={onClickLink}
 *      onRightClickLink={onRightClickLink}
 *      onMouseOverNode={onMouseOverNode}
 *      onMouseOutNode={onMouseOutNode}
 *      onMouseOverLink={onMouseOverLink}
 *      onMouseOutLink={onMouseOutLink}/>
 */
export default class Graph extends React.Component {
    /**
     * Obtain a set of properties which will be used to perform the focus and zoom animation if
     * required. In case there's not a focus and zoom animation in progress, it should reset the
     * transition duration to zero and clear transformation styles.
     * @returns {Object} - Focus and zoom animation properties.
     */
    _generateFocusAnimationProps = () => {
        const { focusedNodeId } = this.state;

        // In case an older animation was still not complete, clear previous timeout to ensure the new one is not cancelled
        if (this.state.enableFocusAnimation) {
            if (this.focusAnimationTimeout) {
                clearTimeout(this.focusAnimationTimeout);
            }

            this.focusAnimationTimeout = setTimeout(
                () => this.setState({ enableFocusAnimation: false }),
                this.state.config.focusAnimationDuration * 1000
            );
        }

        const transitionDuration = this.state.enableFocusAnimation ? this.state.config.focusAnimationDuration : 0;

        return {
            style: { transitionDuration: `${transitionDuration}s` },
            transform: focusedNodeId ? this.state.focusTransformation : null,
        };
    };

    /**
     * Sets d3 tick function and configures other d3 stuff such as forces and drag events.
     * @returns {undefined}
     */
    _graphForcesConfig() {
        this.state.simulation.nodes(this.state.d3Nodes).on("tick", this._tick);

        const forceLink = d3ForceLink(this.state.d3Links)
            .id(l => l.id)
            .distance(this.state.config.d3.linkLength)
            .strength(this.state.config.d3.linkStrength);

        this.state.simulation.force(CONST.LINK_CLASS_NAME, forceLink);

        const customNodeDrag = d3Drag()
            .on("start", this._onDragStart)
            .on("drag", this._onDragMove)
            .on("end", this._onDragEnd);

        d3Select(`#${this.state.id}-${CONST.GRAPH_WRAPPER_ID}`)
            .selectAll(".node")
            .call(customNodeDrag);
    }

    /**
     * Handles d3 drag 'end' event.
     * @returns {undefined}
     */
    _onDragEnd = () =>
        !this.state.config.staticGraph &&
        this.state.config.automaticRearrangeAfterDropNode &&
        this.state.simulation.alphaTarget(this.state.config.d3.alphaTarget).restart();

    /**
     * Handles d3 'drag' event.
     * {@link https://github.com/d3/d3-drag/blob/master/README.md#drag_subject|more about d3 drag}
     * @param  {Object} ev - if not undefined it will contain event data.
     * @param  {number} index - index of the node that is being dragged.
     * @param  {Array.<Object>} nodeList - array of d3 nodes. This list of nodes is provided by d3, each
     * node contains all information that was previously fed by rd3g.
     * @returns {undefined}
     */
    _onDragMove = (ev, index, nodeList) => {
        const id = nodeList[index].id;

        if (!this.state.config.staticGraph) {
            // this is where d3 and react bind
            let draggedNode = this.state.nodes[id];

            draggedNode.x += d3Event.dx;
            draggedNode.y += d3Event.dy;

            // set nodes fixing coords fx and fy
            draggedNode["fx"] = draggedNode.x;
            draggedNode["fy"] = draggedNode.y;

            this._tick();
        }
    };

    /**
     * Handles d3 drag 'start' event.
     * @returns {undefined}
     */
    _onDragStart = () => {
        this.pauseSimulation();
        if (this.state.enableFocusAnimation) {
            this.setState({ enableFocusAnimation: false });
        }
    };

    /**
     * Sets nodes and links highlighted value.
     * @param  {string} id - the id of the node to highlight.
     * @param  {boolean} [value=false] - the highlight value to be set (true or false).
     * @returns {undefined}
     */
    _setNodeHighlightedValue = (id, value = false) =>
        this._tick(
            graphHelper.updateNodeHighlightedValue(this.state.nodes, this.state.links, this.state.config, id, value)
        );

    /**
     * The tick function simply calls React set state in order to update component and render nodes
     * along time as d3 calculates new node positioning.
     * @param {Object} state - new state to pass on.
     * @param {Function} [cb] - optional callback to fed in to {@link setState()|https://reactjs.org/docs/react-component.html#setstate}.
     * @returns {undefined}
     */
    _tick = (state = {}, cb) => (cb ? this.setState(state, cb) : this.setState(state));

    /**
     * Configures zoom upon graph with default or user provided values.<br/>
     * NOTE: in order for users to be able to double click on nodes, we
     * are disabling the native dblclick.zoom from d3 that performs a zoom
     * whenever a user double clicks on top of the graph.
     * {@link https://github.com/d3/d3-zoom#zoom}
     * @returns {undefined}
     */
    _zoomConfig = () => {
        d3Select(`#${this.state.id}-${CONST.GRAPH_WRAPPER_ID}`)
            .call(
                d3Zoom()
                    .scaleExtent([this.state.config.minZoom, this.state.config.maxZoom])
                    .on("zoom", this._zoomed)
            )
            .on("dblclick.zoom", null);
    };

    /**
     * Handler for 'zoom' event within zoom config.
     * @returns {Object} returns the transformed elements within the svg graph area.
     */
    _zoomed = () => {
        const transform = d3Event.transform;

        d3SelectAll(`#${this.state.id}-${CONST.GRAPH_CONTAINER_ID}`).attr("transform", transform);

        this.state.config.panAndZoom && this.setState({ transform: transform.k });
    };

    /**
     * Calls the callback passed to the component.
     * @param  {Object} e - The event of onClick handler.
     * @returns {undefined}
     */
    onClickGraph = e => {
        if (this.state.enableFocusAnimation) {
            this.setState({ enableFocusAnimation: false });
        }

        // Only trigger the graph onClickHandler, if not clicked a node or link.
        // toUpperCase() is added as a precaution, as the documentation says tagName should always
        // return in UPPERCASE, but chrome returns lowercase
        const tagName = e.target && e.target.tagName;
        const name = e.target && e.target.attributes && e.target.attributes.name && e.target.attributes.name.value;
        const svgContainerName = `svg-container-${this.state.id}`;

        if (tagName.toUpperCase() === "SVG" && name === svgContainerName) {
            this.props.onClickGraph && this.props.onClickGraph();
        }
    };

    /**
     * Collapses the nodes, then checks if the click is doubled and calls the callback passed to the component.
     * @param  {string} clickedNodeId - The id of the node where the click was performed.
     * @returns {undefined}
     */
    onClickNode = clickedNodeId => {
        if (this.state.config.collapsible) {
            const leafConnections = collapseHelper.getTargetLeafConnections(
                clickedNodeId,
                this.state.links,
                this.state.config
            );
            const links = collapseHelper.toggleLinksMatrixConnections(
                this.state.links,
                leafConnections,
                this.state.config
            );
            const d3Links = collapseHelper.toggleLinksConnections(this.state.d3Links, links);

            this._tick(
                {
                    links,
                    d3Links,
                },
                () => this.props.onClickNode && this.props.onClickNode(clickedNodeId)
            );
        } else {
            if (!this.nodeClickTimer) {
                this.nodeClickTimer = setTimeout(() => {
                    this.props.onClickNode && this.props.onClickNode(clickedNodeId);
                    this.nodeClickTimer = null;
                }, CONST.TTL_DOUBLE_CLICK_IN_MS);
            } else {
                this.props.onDoubleClickNode && this.props.onDoubleClickNode(clickedNodeId);
                this.nodeClickTimer = clearTimeout(this.nodeClickTimer);
            }
        }
    };

    /**
     * Handles mouse over node event.
     * @param  {string} id - id of the node that participates in the event.
     * @returns {undefined}
     */
    onMouseOverNode = id => {
        this.props.onMouseOverNode && this.props.onMouseOverNode(id);

        this.state.config.nodeHighlightBehavior && this._setNodeHighlightedValue(id, true);
    };

    /**
     * Handles mouse out node event.
     * @param  {string} id - id of the node that participates in the event.
     * @returns {undefined}
     */
    onMouseOutNode = id => {
        this.props.onMouseOutNode && this.props.onMouseOutNode(id);

        this.state.config.nodeHighlightBehavior && this._setNodeHighlightedValue(id, false);
    };

    /**
     * Handles mouse over link event.
     * @param  {string} source - id of the source node that participates in the event.
     * @param  {string} target - id of the target node that participates in the event.
     * @returns {undefined}
     */
    onMouseOverLink = (source, target) => {
        this.props.onMouseOverLink && this.props.onMouseOverLink(source, target);

        if (this.state.config.linkHighlightBehavior) {
            const highlightedLink = { source, target };

            this._tick({ highlightedLink });
        }
    };

    /**
     * Handles mouse out link event.
     * @param  {string} source - id of the source node that participates in the event.
     * @param  {string} target - id of the target node that participates in the event.
     * @returns {undefined}
     */
    onMouseOutLink = (source, target) => {
        this.props.onMouseOutLink && this.props.onMouseOutLink(source, target);

        if (this.state.config.linkHighlightBehavior) {
            const highlightedLink = undefined;

            this._tick({ highlightedLink });
        }
    };

    /**
     * Calls d3 simulation.stop().<br/>
     * {@link https://github.com/d3/d3-force#simulation_stop}
     * @returns {undefined}
     */
    pauseSimulation = () => this.state.simulation.stop();

    /**
     * This method resets all nodes fixed positions by deleting the properties fx (fixed x)
     * and fy (fixed y). Following this, a simulation is triggered in order to force nodes to go back
     * to their original positions (or at least new positions according to the d3 force parameters).
     * @returns {undefined}
     */
    resetNodesPositions = () => {
        if (!this.state.config.staticGraph) {
            for (let nodeId in this.state.nodes) {
                let node = this.state.nodes[nodeId];

                if (node.fx && node.fy) {
                    Reflect.deleteProperty(node, "fx");
                    Reflect.deleteProperty(node, "fy");
                }
            }

            this.state.simulation.alphaTarget(this.state.config.d3.alphaTarget).restart();

            this._tick();
        }
    };

    /**
     * Calls d3 simulation.restart().<br/>
     * {@link https://github.com/d3/d3-force#simulation_restart}
     * @returns {undefined}
     */
    restartSimulation = () => !this.state.config.staticGraph && this.state.simulation.restart();

    constructor(props) {
        super(props);

        if (!this.props.id) {
            utils.throwErr(this.constructor.name, ERRORS.GRAPH_NO_ID_PROP);
        }

        this.focusAnimationTimeout = null;
        this.state = graphHelper.initializeGraphState(this.props, this.state);
    }

    /**
     * @deprecated
     * `componentWillReceiveProps` has a replacement method in react v16.3 onwards.
     * that is getDerivedStateFromProps.
     * But one needs to be aware that if an anti pattern of `componentWillReceiveProps` is
     * in place for this implementation the migration might not be that easy.
     * See {@link https://reactjs.org/blog/2018/06/07/you-probably-dont-need-derived-state.html}.
     * @param {Object} nextProps - props.
     * @returns {undefined}
     */
    componentWillReceiveProps(nextProps) {
        const { graphElementsUpdated, newGraphElements } = graphHelper.checkForGraphElementsChanges(
            nextProps,
            this.state
        );
        const state = graphElementsUpdated ? graphHelper.initializeGraphState(nextProps, this.state) : this.state;
        const newConfig = nextProps.config || {};
        const { configUpdated, d3ConfigUpdated } = graphHelper.checkForGraphConfigChanges(nextProps, this.state);
        const config = configUpdated ? utils.merge(DEFAULT_CONFIG, newConfig) : this.state.config;

        // in order to properly update graph data we need to pause eventual d3 ongoing animations
        newGraphElements && this.pauseSimulation();

        const transform = newConfig.panAndZoom !== this.state.config.panAndZoom ? 1 : this.state.transform;

        const focusedNodeId = nextProps.data.focusedNodeId;
        const d3FocusedNode = this.state.d3Nodes.find(node => `${node.id}` === `${focusedNodeId}`);
        const focusTransformation = graphHelper.getCenterAndZoomTransformation(d3FocusedNode, this.state.config);
        const enableFocusAnimation = this.props.data.focusedNodeId !== nextProps.data.focusedNodeId;

        this.setState({
            ...state,
            config,
            configUpdated,
            d3ConfigUpdated,
            newGraphElements,
            transform,
            focusedNodeId,
            enableFocusAnimation,
            focusTransformation,
        });
    }

    componentDidUpdate() {
        // if the property staticGraph was activated we want to stop possible ongoing simulation
        const shouldPause = this.state.config.staticGraph || this.state.config.staticGraphWithDragAndDrop;

        if (shouldPause) {
            this.pauseSimulation();
        }

        if (!this.state.config.staticGraph && (this.state.newGraphElements || this.state.d3ConfigUpdated)) {
            this._graphForcesConfig();
            if (!this.state.config.staticGraphWithDragAndDrop) {
                this.restartSimulation();
            }
            this.setState({ newGraphElements: false, d3ConfigUpdated: false });
        }

        if (this.state.configUpdated) {
            this._zoomConfig();
            this.setState({ configUpdated: false });
        }
    }

    componentDidMount() {
        if (!this.state.config.staticGraph) {
            this._graphForcesConfig();
        }

        // graph zoom and drag&drop all network
        this._zoomConfig();
    }

    componentWillUnmount() {
        this.pauseSimulation();
        this.nodeClickTimer && clearTimeout(this.nodeClickTimer);
    }

    render() {
        const { nodes, links, defs } = graphRenderer.renderGraph(
            this.state.nodes,
            {
                onClickNode: this.onClickNode,
                onDoubleClickNode: this.onDoubleClickNode,
                onRightClickNode: this.props.onRightClickNode,
                onMouseOverNode: this.onMouseOverNode,
                onMouseOut: this.onMouseOutNode,
            },
            this.state.d3Links,
            this.state.links,
            {
                onClickLink: this.props.onClickLink,
                onRightClickLink: this.props.onRightClickLink,
                onMouseOverLink: this.onMouseOverLink,
                onMouseOutLink: this.onMouseOutLink,
            },
            this.state.config,
            this.state.highlightedNode,
            this.state.highlightedLink,
            this.state.transform
        );

        const svgStyle = {
            height: this.state.config.height,
            width: this.state.config.width,
        };

        const containerProps = this._generateFocusAnimationProps();

        return (
            <div id={`${this.state.id}-${CONST.GRAPH_WRAPPER_ID}`}>
                <svg name={`svg-container-${this.state.id}`} style={svgStyle} onClick={this.onClickGraph}>
                    {defs}
                    <g id={`${this.state.id}-${CONST.GRAPH_CONTAINER_ID}`} {...containerProps}>
                        {links}
                        {nodes}
                    </g>
                </svg>
            </div>
        );
    }
}