added chart

2026-06-17 16:46:40 +02:00
parent 7a90ced98e
commit f4e357a8a1
2 changed files with 283 additions and 11 deletions
@@ -0,0 +1,281 @@
+<script lang="ts">
+  import type { PricePoint } from './lists.svelte';
+
+  let {
+    history,
+    target = null,
+    currency = 'EUR'
+  }: { history: PricePoint[]; target?: number | null; currency?: string | null } = $props();
+
+  // Geometry — a wide, short celestial band. viewBox units; scales to container.
+  const W = 600;
+  const H = 180;
+  const PAD = { t: 16, r: 14, b: 24, l: 46 };
+  const innerW = W - PAD.l - PAD.r;
+  const innerH = H - PAD.t - PAD.b;
+
+  // Chronological, oldest → newest, so the line reads left → right.
+  const points = $derived(
+    [...history].sort((a, b) => +new Date(a.fetched_at) - +new Date(b.fetched_at))
+  );
+
+  const cur = $derived(currency ?? 'EUR');
+
+  const stats = $derived.by(() => {
+    if (points.length === 0) return null;
+    const prices = points.map((p) => p.price);
+    let min = Math.min(...prices);
+    let max = Math.max(...prices);
+    // Fold the target into the vertical range so its line is always visible.
+    if (target != null) {
+      min = Math.min(min, target);
+      max = Math.max(max, target);
+    }
+    if (min === max) {
+      // Flat history — give it breathing room so it doesn't sit on an edge.
+      const pad = Math.max(1, Math.abs(min) * 0.1);
+      min -= pad;
+      max += pad;
+    }
+    const ts = points.map((p) => +new Date(p.fetched_at));
+    const tMin = Math.min(...ts);
+    const tMax = Math.max(...ts);
+    return { min, max, tMin, tMax };
+  });
+
+  function x(t: number): number {
+    if (!stats) return PAD.l;
+    const span = stats.tMax - stats.tMin || 1;
+    return PAD.l + ((t - stats.tMin) / span) * innerW;
+  }
+  function y(price: number): number {
+    if (!stats) return PAD.t;
+    const span = stats.max - stats.min || 1;
+    return PAD.t + (1 - (price - stats.min) / span) * innerH;
+  }
+
+  // Plotted coordinates for each price check.
+  const coords = $derived(
+    points.map((p) => ({ ...p, cx: x(+new Date(p.fetched_at)), cy: y(p.price) }))
+  );
+
+  const linePath = $derived(
+    coords.length
+      ? coords.map((c, i) => `${i === 0 ? 'M' : 'L'} ${c.cx.toFixed(1)} ${c.cy.toFixed(1)}`).join(' ')
+      : ''
+  );
+  // Area = the line, then down to the baseline and back — fills under the curve.
+  const areaPath = $derived(
+    coords.length
+      ? `${linePath} L ${coords[coords.length - 1].cx.toFixed(1)} ${(H - PAD.b).toFixed(1)} ` +
+          `L ${coords[0].cx.toFixed(1)} ${(H - PAD.b).toFixed(1)} Z`
+      : ''
+  );
+
+  // Extremes — gild the lowest (the prophecy), mark the highest in rose.
+  const lowIdx = $derived(
+    coords.length ? coords.reduce((lo, c, i) => (c.price < coords[lo].price ? i : lo), 0) : -1
+  );
+  const highIdx = $derived(
+    coords.length ? coords.reduce((hi, c, i) => (c.price > coords[hi].price ? i : hi), 0) : -1
+  );
+
+  const targetY = $derived(target != null && stats ? y(target) : null);
+  const latest = $derived(coords.length ? coords[coords.length - 1] : null);
+  const onSale = $derived(latest != null && target != null && latest.price <= target);
+
+  // Three horizontal gridlines (min / mid / max) for a sense of scale.
+  const gridLines = $derived.by(() => {
+    if (!stats) return [];
+    return [0, 0.5, 1].map((f) => {
+      const v = stats.min + (stats.max - stats.min) * f;
+      return { v, gy: y(v) };
+    });
+  });
+
+  // Hover — snap to the nearest point in time.
+  let hover = $state<number | null>(null);
+  let svgEl: SVGSVGElement | null = $state(null);
+
+  function onMove(e: PointerEvent) {
+    if (!svgEl || coords.length === 0) return;
+    const rect = svgEl.getBoundingClientRect();
+    const px = ((e.clientX - rect.left) / rect.width) * W;
+    let best = 0;
+    let bestD = Infinity;
+    for (let i = 0; i < coords.length; i++) {
+      const d = Math.abs(coords[i].cx - px);
+      if (d < bestD) {
+        bestD = d;
+        best = i;
+      }
+    }
+    hover = best;
+  }
+
+  function fmtMoney(v: number) {
+    return `${cur} ${v.toFixed(2)}`;
+  }
+  function fmtDay(s: string) {
+    return new Date(s).toLocaleDateString('en-GB', { day: '2-digit', month: 'short' });
+  }
+  function fmtFull(s: string) {
+    return new Date(s).toLocaleDateString('en-GB', {
+      day: '2-digit',
+      month: 'short',
+      hour: '2-digit',
+      minute: '2-digit'
+    });
+  }
+
+  const active = $derived(hover != null ? coords[hover] : null);
+  // Keep the tooltip from spilling off either edge.
+  const tipX = $derived(active ? Math.min(Math.max(active.cx, PAD.l + 56), W - PAD.r - 56) : 0);
+  const uid = 'pc-' + Math.random().toString(36).slice(2, 8);
+</script>
+
+{#if coords.length === 0}
+  <p class="text-xs text-mute">no price checks yet — hit refresh to start tracking.</p>
+{:else}
+  <figure class="m-0">
+    <!-- svelte-ignore a11y_no_noninteractive_element_interactions -->
+    <svg
+      bind:this={svgEl}
+      viewBox="0 0 {W} {H}"
+      class="block w-full select-none overflow-visible"
+      role="img"
+      aria-label="price history chart"
+      onpointermove={onMove}
+      onpointerleave={() => (hover = null)}
+    >
+      <defs>
+        <linearGradient id="{uid}-area" x1="0" y1="0" x2="0" y2="1">
+          <stop offset="0%" stop-color="var(--color-iris)" stop-opacity="0.35" />
+          <stop offset="60%" stop-color="var(--color-iris)" stop-opacity="0.06" />
+          <stop offset="100%" stop-color="var(--color-iris)" stop-opacity="0" />
+        </linearGradient>
+        <linearGradient id="{uid}-line" x1="0" y1="0" x2="1" y2="0">
+          <stop offset="0%" stop-color="var(--color-holo)" />
+          <stop offset="50%" stop-color="var(--color-iris)" />
+          <stop offset="100%" stop-color="var(--color-rose)" />
+        </linearGradient>
+        <filter id="{uid}-glow" x="-20%" y="-20%" width="140%" height="140%">
+          <feGaussianBlur stdDeviation="3.5" result="b" />
+          <feMerge>
+            <feMergeNode in="b" />
+            <feMergeNode in="SourceGraphic" />
+          </feMerge>
+        </filter>
+      </defs>
+
+      <!-- Gridlines + price ticks -->
+      {#each gridLines as g}
+        <line
+          x1={PAD.l}
+          y1={g.gy}
+          x2={W - PAD.r}
+          y2={g.gy}
+          stroke="var(--color-smoke)"
+          stroke-width="1"
+          stroke-dasharray="2 5"
+          opacity="0.6"
+        />
+        <text x={PAD.l - 8} y={g.gy + 3.5} text-anchor="end" class="fill-mute" font-size="10">
+          {g.v.toFixed(0)}
+        </text>
+      {/each}
+
+      <!-- Target line — the price you've been praying for -->
+      {#if targetY != null}
+        <line
+          x1={PAD.l}
+          y1={targetY}
+          x2={W - PAD.r}
+          y2={targetY}
+          stroke="var(--color-mint)"
+          stroke-width="1.25"
+          stroke-dasharray="6 4"
+          opacity="0.8"
+        />
+        <text x={W - PAD.r} y={targetY - 5} text-anchor="end" class="fill-mint" font-size="10">
+          target {target?.toFixed(0)}
+        </text>
+      {/if}
+
+      <!-- Area under the curve -->
+      <path d={areaPath} fill="url(#{uid}-area)" />
+
+      <!-- The price line itself, haloed -->
+      <path
+        d={linePath}
+        fill="none"
+        stroke="url(#{uid}-line)"
+        stroke-width="2.25"
+        stroke-linecap="round"
+        stroke-linejoin="round"
+        filter="url(#{uid}-glow)"
+      />
+
+      <!-- Per-check dots; sold-out checks ringed in rose -->
+      {#each coords as c, i}
+        <circle
+          cx={c.cx}
+          cy={c.cy}
+          r={i === lowIdx || i === highIdx ? 4 : 2.5}
+          fill={i === lowIdx
+            ? 'var(--color-gold)'
+            : i === highIdx
+              ? 'var(--color-rose)'
+              : 'var(--color-iris)'}
+          stroke={c.in_stock === false ? 'var(--color-rose)' : 'var(--color-void)'}
+          stroke-width="1.5"
+        />
+      {/each}
+
+      <!-- Hover crosshair + emphasised point -->
+      {#if active}
+        <line
+          x1={active.cx}
+          y1={PAD.t}
+          x2={active.cx}
+          y2={H - PAD.b}
+          stroke="var(--color-ink)"
+          stroke-width="1"
+          opacity="0.25"
+        />
+        <circle cx={active.cx} cy={active.cy} r="5.5" fill="none" stroke="var(--color-ink)" stroke-width="1.5" />
+        <g transform="translate({tipX}, {Math.max(active.cy - 16, PAD.t + 8)})">
+          <rect x="-54" y="-26" width="108" height="34" rx="6" fill="var(--color-ash)" stroke="var(--color-smoke)" />
+          <text x="0" y="-12" text-anchor="middle" class="fill-ink" font-size="11" font-weight="700">
+            {fmtMoney(active.price)}
+          </text>
+          <text x="0" y="2" text-anchor="middle" class="fill-mute" font-size="9">
+            {fmtFull(active.fetched_at)}
+          </text>
+        </g>
+      {/if}
+
+      <!-- X axis endpoints -->
+      <text x={PAD.l} y={H - 6} text-anchor="start" class="fill-mute" font-size="10">
+        {fmtDay(points[0].fetched_at)}
+      </text>
+      {#if points.length > 1}
+        <text x={W - PAD.r} y={H - 6} text-anchor="end" class="fill-mute" font-size="10">
+          {fmtDay(points[points.length - 1].fetched_at)}
+        </text>
+      {/if}
+    </svg>
+
+    <figcaption class="mt-2 flex flex-wrap items-center justify-between gap-2 text-xs">
+      <span class="flex items-center gap-3 text-mute">
+        <span class="flex items-center gap-1"><span class="inline-block size-2 rounded-full" style="background:var(--color-gold)"></span>low {fmtMoney(coords[lowIdx].price)}</span>
+        <span class="flex items-center gap-1"><span class="inline-block size-2 rounded-full" style="background:var(--color-rose)"></span>high {fmtMoney(coords[highIdx].price)}</span>
+      </span>
+      {#if latest}
+        <span class:text-mint={onSale} class:text-ink={!onSale}>
+          now {fmtMoney(latest.price)}{onSale ? ' ✦' : ''}
+        </span>
+      {/if}
+    </figcaption>
+  </figure>
+{/if}