Add FrontendColors enum generated from the frontend theme

.github/workflows/update_frontend_colors.yml

@@ -0,0 +1,47 @@
+name: Update Frontend Colors
+on:
+  workflow_dispatch:
+  schedule:
+    # Weekly. Regenerates FrontendColors.swift from the frontend `dev` branch
+    # and opens a PR when the palette changed.
+    - cron: '0 7 * * 1'
+
+permissions:
+  contents: read
+
+jobs:
+  update_colors:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      pull-requests: write
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
+        with:
+          ssh-key: ${{ secrets.HOMEASSISTANT_SSH_DEPLOY_KEY }}
+
+      - uses: actions/setup-python@5fda3b95a4ea91299a34e894583c3862153e4b97  # v5.3.0
+        with:
+          python-version: '3.x'
+
+      - name: Regenerate FrontendColors.swift
+        run: python3 Tools/BuildFrontendColors.py
+
+      - name: Commit changes
+        id: commit
+        run: |
+          git config --global user.name 'Home Assistant Bot'
+          git config --global user.email 'hello@home-assistant.io'
+          git add Sources/HADesignSystem/Sources/Colors/FrontendColors.swift
+          if ! git diff --cached --quiet; then
+            git commit -m "Update frontend colors"
+          fi
+          echo "pr_title=$(git log -1 --pretty='%s')" >> "$GITHUB_OUTPUT"
+
+      - name: Create Pull Request
+        uses: peter-evans/create-pull-request@5f6978faf089d4d20b00c7766989d076bb2fc7f1  # v8.1.1
+        with:
+          base: main
+          branch: create-pull-request/update_frontend_colors
+          title: ${{ steps.commit.outputs.pr_title }}
+          body: "Automatically created by ${{ github.actor }}."

Sources/HADesignSystem/Sources/Colors/FrontendColors+Color.swift

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+import Foundation
+import SwiftUI
+import UIKit
+
+public extension FrontendColors {
+    /// The resolved color for the light (default) theme, if the CSS value can be parsed.
+    var lightColor: Color? {
+        Self.color(from: lightValue, scheme: .light)
+    }
+
+    /// The resolved color for the dark theme, falling back to the light value
+    /// when there is no dark override.
+    var darkColor: Color? {
+        Self.color(from: darkValue ?? lightValue, scheme: .dark)
+    }
+
+    /// A color that adapts to the current interface style.
+    ///
+    /// Values that reference custom properties defined outside of
+    /// `color.globals.ts` (for example the `--ha-color-*` core palette) cannot
+    /// be resolved and fall back to `.clear`.
+    var color: Color {
+        Self.adaptiveColor(light: lightColor, dark: darkColor)
+    }
+}
+
+private extension FrontendColors {
+    static func color(from raw: String?, scheme: ColorScheme, visited: Set<FrontendColors> = []) -> Color? {
+        guard let raw = raw?.trimmingCharacters(in: .whitespacesAndNewlines), !raw.isEmpty else {
+            return nil
+        }
+
+        if raw == "transparent" {
+            return .clear
+        }
+        if raw.hasPrefix("#") {
+            return UIColor(rgbaString: raw).map { Color($0) }
+        }
+        if let color = rgbColor(from: raw) {
+            return color
+        }
+        if raw.lowercased().hasPrefix("var(") {
+            return resolveReference(raw, scheme: scheme, visited: visited)
+        }
+        return nil
+    }
+
+    static func resolveReference(
+        _ raw: String,
+        scheme: ColorScheme,
+        visited: Set<FrontendColors>
+    ) -> Color? {
+        guard let open = raw.firstIndex(of: "("), raw.hasSuffix(")") else {
+            return nil
+        }
+        let inner = raw[raw.index(after: open) ..< raw.index(before: raw.endIndex)]
+        let arguments = splitTopLevel(String(inner))
+        guard let name = arguments.first?.trimmingCharacters(in: .whitespaces), !name.isEmpty else {
+            return nil
+        }
+        let fallback = arguments.count > 1
+            ? arguments.dropFirst().joined(separator: ",").trimmingCharacters(in: .whitespaces)
+            : nil
+
+        if let referenced = FrontendColors(rawValue: name), !visited.contains(referenced) {
+            let referencedRaw = scheme == .dark
+                ? (referenced.darkValue ?? referenced.lightValue)
+                : referenced.lightValue
+            if let resolved = color(from: referencedRaw, scheme: scheme, visited: visited.union([referenced])) {
+                return resolved
+            }
+        }
+        if let fallback {
+            return color(from: fallback, scheme: scheme, visited: visited)
+        }
+        return nil
+    }
+
+    static func rgbColor(from value: String) -> Color? {
+        guard let regex = rgbFunctionRegex else {
+            return nil
+        }
+        let range = NSRange(value.startIndex ..< value.endIndex, in: value)
+        guard let match = regex.firstMatch(in: value, range: range) else {
+            return nil
+        }
+        func component(at index: Int) -> Double? {
+            guard let range = Range(match.range(at: index), in: value) else {
+                return nil
+            }
+            return Double(value[range])
+        }
+        guard let red = component(at: 1), let green = component(at: 2), let blue = component(at: 3) else {
+            return nil
+        }
+        let alpha = component(at: 4) ?? 1
+        return Color(
+            .sRGB,
+            red: red / 255,
+            green: green / 255,
+            blue: blue / 255,
+            opacity: min(max(alpha, 0), 1)
+        )
+    }
+
+    static func splitTopLevel(_ string: String) -> [String] {
+        var result: [String] = []
+        var depth = 0
+        var current = ""
+        for character in string {
+            switch character {
+            case "(":
+                depth += 1
+                current.append(character)
+            case ")":
+                depth -= 1
+                current.append(character)
+            case "," where depth == 0:
+                result.append(current)
+                current = ""
+            default:
+                current.append(character)
+            }
+        }
+        result.append(current)
+        return result
+    }
+
+    static func adaptiveColor(light: Color?, dark: Color?) -> Color {
+        #if os(watchOS)
+        return dark ?? light ?? .clear
+        #else
+        let lightColor = light ?? dark ?? .clear
+        let darkColor = dark ?? light ?? .clear
+        return Color(UIColor { traits in
+            traits.userInterfaceStyle == .dark ? UIColor(darkColor) : UIColor(lightColor)
+        })
+        #endif
+    }
+
+    static let rgbFunctionRegex = try? NSRegularExpression(
+        pattern: #"^rgba?\(\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d+)\s*(?:,\s*([0-9.]+)\s*)?\)$"#,
+        options: [.caseInsensitive]
+    )
+}