class Algorithm{

    constructor(){
        this.startNode = game.startNode;
        this.targetNode = game.targetNode;

        this.grid = game.grid;

        this.startDate = new Date();
        this.timeDiff = 0;
    }

    get running(){
        return !this.hasSucceeded && !this.hasFailed;
    }

    display(){
        push();
        scale(1 / this.grid.nodeSize.x, 1 / this.grid.nodeSize.y);
        fill(0);
        textSize(20);
        textAlign(CENTER, TOP);
        text('Time: ' + this.timeDiff / 1000 + 's', this.grid.size / 2, -this.grid.nodeSize.y / 2 - 50);
        pop();
    }

    update(){
        this.timeDiff = new Date().getTime() - this.startDate.getTime();
    }

    success(){
        console.log('Success!');
        this.hasSucceeded = true;
    }

    failed(){
        console.log('Failed!');
        this.hasFailed = true;
    }

}

function startAlgorithm(){
    switch ($('#algorithm_type').val()){
        case 'astar':
            game.start(new AStar());
            break;
        case 'dijkstra':
            game.start(new Dijkstra());
            break;
        case 'dstar':
            game.start(new DStar());
            break;
    }
}


class DStar extends Algorithm{

    constructor() {
        super();

        this.openList = []
    }


}


class AStar extends Algorithm{

    constructor(){
        super();

        this.startNode.f = 0;
        this.startNode.g = 0;

        this.openList = [this.startNode];
        this.closedList = [];
    }

    get minFNodeIndex(){
        let f = this.openList[0].f, index = 0;
        this.openList.forEach((n, i) => {
            if (n.f < f){
                f = n.f;
                index = i;
            }
        });
        return index;
    }

    update(){
        if (!this.running){
            return;
        }

        super.update();

        if (!this.openList.length){
            this.failed();
        } else {
            let index = this.minFNodeIndex;
            let currentNode = this.openList[index];
            this.openList.splice(index, 1);

            if (currentNode === this.targetNode){
                this.success();
            } else {
                this.closedList.push(currentNode);

                currentNode.successors.forEach(successor => {

                    if (this.closedList.find(n => n === successor)){
                        return;
                    }

                    let provisionalG = currentNode.g + currentNode.pos.dist(successor.pos);
                    if (this.openList.find(n => n === successor) && provisionalG >= successor.g){
                        return;
                    }

                    successor.predecessor = currentNode
                    successor.g = provisionalG;

                    successor.f = provisionalG + successor.distanceToTarget;
                    if (!this.openList.find(n => n === successor)){
                        this.openList.push(successor);
                    }
                });
            }
        }
    }

    display(appearance, isInformationVisible, pathSmoothness){
        super.display();

        if (isInformationVisible){

            if (appearance === 'Circles'){
                let r = 0.5;

                fill(200);
                this.openList.forEach(n => {
                    ellipse(n.pos.x, n.pos.y, r * 2);
                });

                fill(100);
                this.closedList.forEach(n => {
                    if (n === this.startNode)
                        return;
                    ellipse(n.pos.x, n.pos.y, r * 2);
                });
            }

            if (appearance === 'Rectangles'){
                fill(200);
                this.openList.forEach(n => {
                    rect(n.pos.x - 0.5, n.pos.y - 0.5, 1, 1);
                });

                fill(100);
                this.closedList.forEach(n => {
                    if (n === this.startNode)
                        return;
                    rect(n.pos.x - 0.5, n.pos.y - 0.5, 1, 1);
                });
            }
        }


        noFill();
        stroke(50, 255, 50);
        strokeWeight(0.2);

        let node;
        if (!this.openList.length){
            node = this.closedList[this.closedList.length - 1];
        } else {
            node = this.openList[this.minFNodeIndex];
        }
        if (this.hasSucceeded){
            node = this.targetNode;
        }
        if (node){

            if (pathSmoothness){
                beginShape();
                vertex(node.pos.x, node.pos.y);
                while (node.predecessor){
                    node = node.predecessor;

                    if (!node.predecessor){
                        quadraticVertex(node.pos.x, node.pos.y, node.pos.x, node.pos.y);
                        endShape();
                    } else {
                        let cx = (node.pos.x + node.predecessor.pos.x) / 2;
                        let cy = (node.pos.y + node.predecessor.pos.y) / 2;
                        quadraticVertex(node.pos.x, node.pos.y, cx, cy);
                    }
                }

            } else {
                while (node.predecessor){
                    line(node.pos.x, node.pos.y, node.predecessor.pos.x, node.predecessor.pos.y);
                    node = node.predecessor;
                }
            }
        }
    }

}

class Dijkstra extends Algorithm{

    constructor(){
        super();

        this.nodes = this.grid.allowedNodes.slice();
        this.nodes.forEach(n => n.distance = Infinity);
        this.startNode.distance = 0;
    }

    get minDistanceNodeIndex(){
        let index = 0, distance = this.nodes[0].distance;
        this.nodes.forEach((n, i) => {
            if (n.distance < distance){
                index = i;
                distance = n.distance;
            }
        });
        return index;
    }

    update(){
        if (!this.running){
            return;
        }
        super.update();

        let index = this.minDistanceNodeIndex;
        let currentNode = this.nodes[index];

        this.nodes.splice(index, 1);

        if (currentNode === this.targetNode){
            this.success();
        }

        currentNode.successors.forEach(s => {
            if (this.nodes.find(n => n === s)){
                let alternativeDistance = currentNode.distance + currentNode.pos.dist(s.pos);
                if (alternativeDistance < s.distance){
                    s.distance = alternativeDistance;
                    s.predecessor = currentNode;
                }
            }
        })
    }

    display(appearance, isInformationVisible, pathSmoothness){
        super.display();

        if (isInformationVisible){
            if (appearance === 'Circles'){
                let r = 0.5;
                fill(100);
                this.nodes.forEach(n => {
                    if (n === this.startNode || n === this.targetNode)
                        return;
                    ellipse(n.pos.x, n.pos.y, r * 2);
                });
            }

            if (appearance === 'Rectangles'){
                fill(100);
                this.nodes.forEach(n => {
                    if (n === this.startNode || n === this.targetNode)
                        return;
                    rect(n.pos.x - 0.5, n.pos.y - 0.5, 1, 1);
                });
            }
        }


        noFill();
        stroke(50, 255, 50);
        strokeWeight(0.2);

        let node = this.nodes[this.minDistanceNodeIndex];
        if (this.hasSucceeded){
            node = this.targetNode;
        }
        if (node){

            if (pathSmoothness){
                beginShape();
                vertex(node.pos.x, node.pos.y);
                while (node.predecessor){
                    node = node.predecessor;

                    if (!node.predecessor){
                        quadraticVertex(node.pos.x, node.pos.y, node.pos.x, node.pos.y);
                        endShape();
                    } else {
                        let cx = (node.pos.x + node.predecessor.pos.x) / 2;
                        let cy = (node.pos.y + node.predecessor.pos.y) / 2;
                        quadraticVertex(node.pos.x, node.pos.y, cx, cy);
                    }
                }
                
            } else {
                while (node.predecessor){
                    line(node.pos.x, node.pos.y, node.predecessor.pos.x, node.predecessor.pos.y);
                    node = node.predecessor;
                }
            }
        }
    }

}