const canvas = document.getElementById('canvas')
const ctx    = canvas.getContext('2d')

const width  = canvas.width;
const height = canvas.height;

let current;
let selection = []

const tools = {
    graffity: {
        mousemove(e){ //e.buttons 0b00000x11 & 0b00000100 == x
            (e.buttons & 1) && new Circle(e.clientX, e.clientY, +size.value, color.value)
        }
    },
    circle: {
        mousedown(e){
            current = new Circle(e.clientX,e.clientY, 1, color.value)
        },
        mousemove(e){
            if (!current) return;

            current.radius = current.distanceTo(e.clientX, e.clientY)
            Drawable.drawAll()
        },

        mouseup(e){
            current = null
        }
    },
    line: {
        mousedown(e){
            current = new Line(e.clientX, e.clientY, 0, 0, color.value, +size.value)
        },
        mousemove(e){
            if (!current) return;

            current.width = e.clientX - current.x
            current.height = e.clientY - current.y

            Drawable.drawAll()
        },

        mouseup(e){
            current = null
        }
    },
    rectangle: {
        mousedown(e){
            current = new Rectangle(e.clientX, e.clientY, 0, 0, color.value)
        },
        mousemove(e){
            if (!current) return;

            current.width = e.clientX - current.x
            current.height = e.clientY - current.y

            Drawable.drawAll()
        },

        mouseup(e){
            current = null
        }
    },
    ellipse: {
        mousedown(e){
            current = new Ellipse(e.clientX, e.clientY, 0, 0, color.value)
        },
        mousemove(e){
            if (!current) return;

            current.width = e.clientX - current.x
            current.height = e.clientY - current.y

            Drawable.drawAll()
        },

        mouseup(e){
            current = null
        }
    },
    select: {
        click(e){
            console.log(e)
            let found = Drawable.instances.filter(c => c.in && c.in(e.clientX, e.clientY))
            if (found.length){
                if (e.ctrlKey){
                    selection.push(found.pop())
                }
                else {
                    selection = [found.pop()]
                }
            }
            else {
                if (!e.ctrlKey) selection = []
            }

            Drawable.drawAll(selection)
        },
        mousedown(e){
            //
        },
        mousemove(e){

        },

        mouseup(e){
            //x,y, w, h прямоугольника
            //selection - только те элеменеты Drawable.instances которые в границах прямоугольника.
        },
    }
}



function superHandler(evt){
    let t = tools[tool.value]
    if (typeof t[evt.type] === 'function')
        t[evt.type].call(this, evt)
}

canvas.onmousemove = superHandler
canvas.onmouseup   = superHandler
canvas.onmousedown = superHandler
canvas.onclick = superHandler

////


function Drawable(){
   Drawable.addInstance(this);   
}

const distance = (x1,y1, x2, y2) => ((x1-x2)**2 + (y1-y2)**2)**0.5

Drawable.prototype.draw = function(){};
Drawable.prototype.distanceTo = function(x,y){
    if (typeof this.x !== 'number' ||
        typeof this.y !== 'number'){
        return NaN
    }
    return distance(this.x, this.y, x, y)
};
Drawable.instances = [];
Drawable.addInstance = function(item){
    Drawable.instances.push(item);
}

Drawable.drawAll = function(selection=[]){
    ctx.clearRect(0,0,width,height);
    Drawable.forAll(item => item.draw())
    selection.forEach(item  => item.draw(true))
}

Drawable.forAll = function(callback){
    for(var i = 0; i<Drawable.instances.length;i++){
        callback(Drawable.instances[i])
    }
}

class Circle extends Drawable {
    constructor(x,y,radius, color){
        super()
        this.x      = x;
        this.y      = y;
        this.radius = radius;
        this.color  = color;

        this.draw(); 
    }

    draw(selected){
        ctx.beginPath();
        ctx.arc(this.x, this.y, this.radius, 0, 2 * Math.PI);
        ctx.closePath();
        ctx.fillStyle = this.color;
        if (selected){
            ctx.lineWidth = 2
            ctx.stroke();
        }
        ctx.fill();
    }

    in(x,y){
        return this.distanceTo(x,y) < this.radius
    }

    inBounds(x,y,w,h){ // x = 100, this.x = 102, w = 5
        return this.x >= x && this.x <= x + w &&
               this.y >= y && this.y <= y + h 
    }
}


class Line extends Drawable {
    constructor(x,y, width, height, color, lineWidth){
        super()
        this.x      = x;
        this.y      = y;
        this.width  = width;
        this.height = height;
        this.color  = color;
        this.lineWidth  = lineWidth;


        this.draw(); 
    }
    
    get length() {
        return this.distanceTo(this.x + this.width, this.y + this.height)
    }
    
    draw(selected){
        ctx.beginPath();
        ctx.moveTo(this.x, this.y);
        ctx.lineTo(this.x + this.width, this.y + this.height);
        ctx.closePath();
        ctx.strokeStyle = this.color;
        ctx.lineWidth   = this.lineWidth
        ctx.stroke();
    }

    in(x,y) {
        let rotationAngleAlph = Math.atan2(this.height, this.width)
        //console.log('raznici', y - this.y, x - this.x)
        let mouseAngleBeta = Math.atan2(y - this.y, x - this.x)
        let angleDiff = mouseAngleBeta - rotationAngleAlph
        
        //x on 0 do dlinna y ot 0 do width
        

        //let newX = Math.cos(angleDiff) * this.distanceTo(x,y)
        let newX = Math.cos(rotationAngleAlph) * this.distanceTo(x,y)

        //let newY = Math.sin(angleDiff) * this.distanceTo(x,y)
        let newY = Math.sin(mouseAngleBeta) * this.distanceTo(x,y)


        console.log('ot nachala do kincza X', newX)     
        console.log('dist . length', this.distanceTo(x,y) / this.length)
        console.log('ot nachala do kincza Y', newY)
        console.log(angleDiff, rotationAngleAlph, mouseAngleBeta)
        console.log(this.lineWidth)
        console.log('v line x',  0 <= newX && newX <= this.distanceTo(x,y) / this.length )
        console.log('v line y', ( -this.lineWidth/2 <= newY && newY <= this.lineWidth/2 ))
        return ( 0 >= newX && newX <= (this.distanceTo(x,y)/this.length) )  && ( -this.lineWidth/2 >= newY && newY <= this.lineWidth/2 )


    }
}

color.onchange = () => {
    selection.forEach(c => c.color = color.value)
    Drawable.drawAll(selection)
}

document.getElementById('delete').onclick = () =>{
    Drawable.instances = Drawable.instances.filter(item => !selection.includes(item))
    selection = []
    Drawable.drawAll()
}

class Rectangle extends Drawable {
    constructor(x, y, width, height, color) {
        super()
        this.x      = x;
        this.y      = y;
        this.width  = width;
        this.height = height;
        this.color  = color;

        this.draw();   
    }


    draw(selected){
        ctx.beginPath();
        ctx.moveTo(this.x, this.y);
        ctx.lineTo(this.x + this.width, this.y + this.height);
        ctx.closePath();
        ctx.strokeStyle = this.color;
        ctx.fillStyle = this.color;
        ctx.fillRect(this.x, this.y, this.width, this.height)
        ctx.stroke()
        if (selected){
            ctx.beginPath();
            ctx.rect(this.x, this.y, this.width, this.height)
            ctx.lineWidth = 2
            ctx.strokeStyle = 'black'
            ctx.closePath();

            ctx.stroke()
        }
        ctx.fill()
    }


    in(x,y){
        if((x > this.x && x < this.x + this.width) && (y > this.y && y < this.y + this.height)) {
            return true
        }
        return false
    }
}

class Ellipse extends Drawable {
    constructor(x,y, width, height, color){
        super()
        this.x      = x;
        this.y      = y;
        this.width  = width;
        this.height = height;
        this.color  = color;

        this.draw(); 
    }

    get rx() {
        return this.width / 2
    }

    get ry() {
        return this.height / 2
    }

    get h() {
        return this.x + this.rx
    }

    get k() {
        return this.y + this.ry
    }

    draw(selected){
        ctx.beginPath();
        ctx.fillStyle = this.color;
        ctx.ellipse(
            this.h,
            this.k,
            this.rx > 0? this.rx : -(this.rx),
            this.ry > 0? this.ry : -(this.ry),
            0,
            0,
            Math.PI * 2
        )
        if (selected){
            ctx.beginPath();
            ctx.ellipse(
                this.h,
                this.k,
                this.rx > 0? this.rx : -(this.rx),
                this.ry > 0? this.ry : -(this.ry),
                0,
                0,
                Math.PI * 2
            )
            
            ctx.lineWidth = 2
            ctx.strokeStyle = 'black'
            ctx.closePath();
            ctx.stroke()
        }
        ctx.fill()
    }

    in(x,y){
        return (((x - this.h)**2) / ((this.rx)**2)) + (((y - this.k)**2) / ((this.ry)**2)) <= 1
    }
}