class Player {
    constructor(wrapperEl) {
        this.wrapperEl = wrapperEl;
        this.svgEl = document.createElementNS('http://www.w3.org/2000/svg', 'svg');
        this.wrapperEl.appendChild(this.svgEl);

    }

    playlist(url) {
        const request = new Request(url, {
            method: 'GET',
        });


        fetch(request)
        .then(response => response.json())
        .then(data => {
            let playlist = this.wrapperEl.querySelector('.playlist');
            if(!playlist) {
                playlist = document.createElement('nav');
                playlist.classList.add('playlist');
                this.wrapperEl.appendChild(playlist)
            }
            else{
                playlist.innerHTML = "";
            }

            const listEl = document.createElement("ul");
            for(let fileUrl of data) {
                const liEl = document.createElement("li");
                liEl.innerText = fileUrl
                liEl.addEventListener('click', (e) => {
                    this.play(fileUrl);
                    playlist.style.display = "none";
                });
                listEl.appendChild(liEl);
            }
            playlist.appendChild(listEl);
            // do something with the data sent in the request
        });
    }

    play(file) {
        const request = new Request(file, {
            method: 'GET',
        });


        fetch(request)
        .then(response => response.json())
        .then(data => {
            this.playStrokes(data)
            // do something with the data sent in the request
        });

    }

    playStrokes(drawing){
        this.strokes = drawing.shape;
        this.currentPath = null;
        this.dimensions = drawing.dimensions;
        this.svgEl.setAttribute('viewBox', `0 0 ${this.dimensions[0]} ${this.dimensions[1]}`)
        this.startTime = window.performance.now() - this.strokes[0].points[0][3];
        this.playStroke(0,1);
    }

    playStroke(path_i, point_i){
        const path = this.strokes[path_i];
        // console.log(path);
        let pathEl = this.svgEl.querySelector(`.path${path_i}`);
        if(!pathEl){
            pathEl = document.createElementNS('http://www.w3.org/2000/svg', 'path');
            pathEl.style.stroke = path.color;
            pathEl.classList.add('path'+path_i)
            this.svgEl.appendChild(pathEl)
        }
        
        const d = this.strokes2D(path.points.slice(0, point_i));
        pathEl.setAttribute('d', d);
        
        let next_path, next_point,t;
        if(path.points.length > point_i + 1){
            next_path = path_i;
            next_point = point_i + 1;
            t = path.points[next_point][3];// - path.points[point_i][3];
            // setTimeout(() => this.playStroke(next_path, next_point), dt);
        } else if(this.strokes.length > path_i + 1) {
            next_path = path_i + 1;
            next_point = 1;
            t = this.strokes[next_path].points[next_point][3];// - path.points[point_i][3];
            // use starttime instead of diff, to prevent floating
        } else {
            console.log('done');
            return
        }

        const dt = t - (window.performance.now() - this.startTime);
        setTimeout(() => this.playStroke(next_path, next_point), dt);
    }

    playUntil(path_i){
        // for scrubber
    }


    strokes2D(strokes) {
        // strokes to a d attribute for a path
        let d = "";
        let last_stroke = undefined;
        let cmd = "";
        for (let stroke of strokes) {
            if (!last_stroke) {
                d += `M${stroke[0] * this.dimensions[0]},${stroke[1] * this.dimensions[1]} `;
                cmd = 'M';
            } else {
                if (last_stroke[2] == 1) {
                    d += " m";
                    cmd = 'm';
                } else if (cmd != 'l') {
                    d += ' l ';
                    cmd = 'l';
                }
                let rel_stroke = [stroke[0] - last_stroke[0], stroke[1] - last_stroke[1]];
                d += `${rel_stroke[0] * this.dimensions[0]},${rel_stroke[1] * this.dimensions[1]} `;
            }
            last_stroke = stroke;

        }
        return d;
    }
}