class MiniChart {
    constructor(canvasId, color = '#7aa2f7') {
        this.canvas = document.getElementById(canvasId);
        this.ctx = this.canvas.getContext('2d');
        this.color = color;
        this.data = new Array(60).fill(0); // 60秒历史
        this.maxVal = 100;

        this.resize();
        window.addEventListener('resize', () => this.resize());
    }

    resize() {
        var rect = this.canvas.parentElement.getBoundingClientRect();
        this.canvas.width = rect.width - 24;
        this.canvas.height = 60;
        this.draw();
    }

    update(val) {
        this.data.push(val);
        if (this.data.length > 60) this.data.shift();
        this.maxVal = Math.max.apply(null, this.data.concat([100]));
        this.draw();
    }

    draw() {
        if (!this.ctx) return;
        var ctx = this.ctx;
        var w = this.canvas.width;
        var h = this.canvas.height;

        ctx.clearRect(0, 0, w, h);

        ctx.strokeStyle = this.color;
        ctx.lineWidth = 2;
        ctx.beginPath();

        var self = this;
        this.data.forEach(function(v, i) {
            var x = (i / 59) * w;
            var y = h - (v / self.maxVal) * (h - 10);
            if (i === 0) ctx.moveTo(x, y);
            else ctx.lineTo(x, y);
        });
        ctx.stroke();

        // 填充渐变
        ctx.lineTo(w, h);
        ctx.lineTo(0, h);
        ctx.fillStyle = this.color + '20';
        ctx.fill();
    }
}

/* ── Dual-line chart (e.g. download + upload speed) ── */
class DualLineChart {
    constructor(canvasId, colorA, colorB) {
        this.canvas = document.getElementById(canvasId);
        this.ctx = this.canvas.getContext('2d');
        this.colorA = colorA || '#bb9af7'; // solid line (download)
        this.colorB = colorB || '#c0a8f0'; // dashed line (upload)
        this.dataA = new Array(60).fill(0);
        this.dataB = new Array(60).fill(0);
        this.maxVal = 100;
        this.applyResize();
        window.addEventListener('resize', () => this.applyResize());
    }

    applyResize() {
        var rect = this.canvas.parentElement.getBoundingClientRect();
        this.canvas.width = rect.width - 24;
        this.canvas.height = 60;
        this.draw();
    }

    update(valA, valB) {
        this.dataA.push(valA);
        this.dataB.push(valB);
        if (this.dataA.length > 60) { this.dataA.shift(); this.dataB.shift(); }
        var all = this.dataA.concat(this.dataB).concat([100]);
        this.maxVal = Math.max.apply(null, all);
        this.draw();
    }

    draw() {
        if (!this.ctx) return;
        var ctx = this.ctx;
        var w = this.canvas.width;
        var h = this.canvas.height;

        var self = this;

        // Y-axis: range from -5% to 100%, so zero never hugs the bottom
        var pad = Math.max(10, self.maxVal * 0.05);
        var range = self.maxVal + pad; // e.g. 0..100 becomes -5..100

        ctx.clearRect(0, 0, w, h);

        // ── Line A: solid (download) ──
        ctx.strokeStyle = this.colorA;
        ctx.lineWidth = 1.8;
        ctx.setLineDash([]);
        ctx.beginPath();
        this.dataA.forEach(function(v, i) {
            var x = (i / 59) * w;
            var y = h - ((v + pad) / range) * (h - 8);
            if (i === 0) ctx.moveTo(x, y);
            else ctx.lineTo(x, y);
        });
        ctx.stroke();

        // ── Line B: dashed (upload) ──
        ctx.strokeStyle = this.colorB;
        ctx.lineWidth = 1.4;
        ctx.setLineDash([4, 4]);
        ctx.beginPath();
        this.dataB.forEach(function(v, i) {
            var x = (i / 59) * w;
            var y = h - ((v + pad) / range) * (h - 8);
            if (i === 0) ctx.moveTo(x, y);
            else ctx.lineTo(x, y);
        });
        ctx.stroke();
        ctx.setLineDash([]);
    }
}

window.MiniChart = MiniChart;
window.DualLineChart = DualLineChart;