[easytier-uptime] support tag in node list (#1487)

easytier-contrib/easytier-uptime/frontend/src/utils/tagColor.js

@@ -0,0 +1,62 @@
+// Deterministic tag color generator (pure frontend)
+// Same tag => same color; different tags => different colors
+
+function stringHash(str) {
+  const s = String(str)
+  let hash = 5381
+  for (let i = 0; i < s.length; i++) {
+    hash = (hash * 33) ^ s.charCodeAt(i)
+  }
+  return hash >>> 0 // ensure positive
+}
+
+function hslToRgb(h, s, l) {
+  // h,s,l in [0,1]
+  let r, g, b
+
+  if (s === 0) {
+    r = g = b = l // achromatic
+  } else {
+    const hue2rgb = (p, q, t) => {
+      if (t < 0) t += 1
+      if (t > 1) t -= 1
+      if (t < 1 / 6) return p + (q - p) * 6 * t
+      if (t < 1 / 2) return q
+      if (t < 2 / 3) return p + (q - p) * (2 / 3 - t) * 6
+      return p
+    }
+
+    const q = l < 0.5 ? l * (1 + s) : l + s - l * s
+    const p = 2 * l - q
+    r = hue2rgb(p, q, h + 1 / 3)
+    g = hue2rgb(p, q, h)
+    b = hue2rgb(p, q, h - 1 / 3)
+  }
+
+  return [Math.round(r * 255), Math.round(g * 255), Math.round(b * 255)]
+}
+
+function rgbToHex(r, g, b) {
+  const toHex = (v) => v.toString(16).padStart(2, '0')
+  return `#${toHex(r)}${toHex(g)}${toHex(b)}`
+}
+
+export function getTagStyle(tag) {
+  const hash = stringHash(tag)
+  const hue = hash % 360 // 0-359
+  const saturation = 65 // percentage
+  const lightness = 47 // percentage
+
+  const rgb = hslToRgb(hue / 360, saturation / 100, lightness / 100)
+  const hex = rgbToHex(rgb[0], rgb[1], rgb[2])
+
+  // Perceived brightness for text color selection
+  const brightness = rgb[0] * 0.299 + rgb[1] * 0.587 + rgb[2] * 0.114
+  const textColor = brightness > 160 ? '#1f1f1f' : '#ffffff'
+
+  return {
+    backgroundColor: hex,
+    borderColor: hex,
+    color: textColor
+  }
+}