Quick and dirty figma importer

Package.swift

@@ -6,7 +6,7 @@ import PackageDescription
 let package = Package(
     name: "MakeColors",
     platforms: [
-        .macOS("10.15.4"),
+        .macOS("12.0"),
     ],
     dependencies: [
         .package(url: "https://github.com/apple/swift-argument-parser", .upToNextMinor(from: "1.1.4")),

Sources/MakeColors/Importers/Figma/FigmaImporter.swift

@@ -0,0 +1,149 @@
+import Foundation
+
+enum FigmaErrors: Error {
+    case invalidUrl
+    case missingToken
+    case invalidResponse
+    case missingColor(String)
+}
+
+class FigmaImporter: Importer {
+    let key: String
+    let token: String
+
+    required init(source: String) throws {
+        // https://www.figma.com/file/:key/:title
+        guard
+            let url = URL(string: source),
+            url.host == "www.figma.com",
+            url.pathComponents.count >= 4,
+            url.pathComponents[1] == "file"
+        else {
+            throw FigmaErrors.invalidUrl
+        }
+
+        key = url.pathComponents[2]
+
+        guard let token = ProcessInfo.processInfo.environment["FIGMA_TOKEN"] else {
+            throw FigmaErrors.missingToken
+        }
+
+        self.token = token
+    }
+
+    func read() async throws -> [String: ColorDef] {
+        let styles = try await request(StylesResponse.self, path: "/v1/files/\(key)/styles").meta.styles
+            .filter { $0.styleType == "FILL" }
+
+        let ids = styles.map(\.nodeId).joined(separator: ",")
+
+        let nodes = try await request(
+            NodesResponse.self,
+            path: "/v1/files/\(key)/nodes",
+            query: [URLQueryItem(name: "ids", value: ids)]
+        )
+        .nodes
+
+        var result: [String: ColorDef] = [:]
+        result.reserveCapacity(styles.count)
+
+        for style in styles {
+            guard
+                let node = nodes[style.nodeId],
+                let fill = node.document.fills.first(where: { $0.type == "SOLID" })
+            else {
+                throw FigmaErrors.missingColor(style.name)
+            }
+
+            if node.document.fills.count > 1 {
+                print("Warning: Multiple fills defined for \(style.name)")
+            }
+
+            if fill.blendMode != "NORMAL" {
+                print("Warning: Blend mode \(fill.blendMode) used for \(style.name)")
+            }
+
+            guard !result.keys.contains(style.name) else {
+                throw Errors.duplicateColor(style.name)
+            }
+
+            result[style.name] = .color(Color(fill.color))
+        }
+
+        return result
+    }
+
+    func request<T: Decodable>(_: T.Type = T.self, path: String, query: [URLQueryItem]? = nil) async throws -> T {
+        var components = URLComponents()
+        components.scheme = "https"
+        components.host = "api.figma.com"
+        components.path = path
+        components.queryItems = query
+
+        guard let url = components.url else {
+            fatalError("Cannot create url. Components: \(components)")
+        }
+
+        var request = URLRequest(url: url)
+        request.setValue(token, forHTTPHeaderField: "X-Figma-Token")
+
+        let (data, response) = try await URLSession.shared.data(for: request)
+
+        guard let response = response as? HTTPURLResponse else {
+            fatalError("Non-HTTP-Response received: \(response)")
+        }
+
+        guard response.statusCode == 200 else {
+            throw FigmaErrors.invalidResponse
+        }
+
+        let decoder = JSONDecoder()
+        decoder.keyDecodingStrategy = .convertFromSnakeCase
+        return try decoder.decode(T.self, from: data)
+    }
+}
+
+struct StylesResponse: Decodable {
+    var meta: Meta
+    struct Meta: Decodable {
+        var styles: [Style]
+    }
+
+    struct Style: Decodable {
+        var nodeId: String
+        var styleType: String
+        var name: String
+        var description: String
+    }
+}
+
+struct NodesResponse: Decodable {
+    var nodes: [String: Node]
+
+    struct Node: Decodable {
+        var document: Document
+    }
+
+    struct Document: Decodable {
+        var fills: [Fill]
+    }
+
+    struct Fill: Decodable {
+        var blendMode: String
+        var type: String
+        var color: Color
+    }
+
+    struct Color: Decodable {
+        var r, g, b, a: Float
+    }
+}
+
+extension Color {
+    init(_ color: NodesResponse.Color) {
+        red = UInt8(truncatingIfNeeded: Int(color.r * 0xFF))
+        green = UInt8(truncatingIfNeeded: Int(color.g * 0xFF))
+        blue = UInt8(truncatingIfNeeded: Int(color.b * 0xFF))
+        alpha = UInt8(truncatingIfNeeded: Int(color.a * 0xFF))
+    }
+}

Sources/MakeColors/MakeColors.swift

@@ -22,6 +22,7 @@ private struct GeneratorOption: EnumerableFlag, CustomStringConvertible {
 private struct ImporterOption: CaseIterable, ExpressibleByArgument, CustomStringConvertible {
     static let allCases: [ImporterOption] = [
         .list,
+        .init(type: FigmaImporter.self),
     ]
 
     static let list = ImporterOption(type: ListImporter.self)