Update package

Sources/CommandLineToolSupport/Intramodular/TerminalColorCapability.swift

@@ -0,0 +1,127 @@
+//
+// Copyright (c) Vatsal Manot
+//
+
+import FoundationX
+
+/// Represents the color support capabilities of a terminal environment
+public enum TerminalColorCapability {
+    /// No color support
+    case dumb
+    /// Basic 16-color ANSI support
+    case ansi16
+    /// Extended 256-color ANSI support
+    case ansi256
+    /// Full 24-bit true color support (16 million colors)
+    case ansi16m
+
+    private static var cachedCapability: TerminalColorCapability?
+
+    /// The current terminal's color capability
+    public static var current: TerminalColorCapability {
+        if let cached = cachedCapability {
+            return cached
+        }
+
+        let capability = determineColorCapability()
+        cachedCapability = capability
+        return capability
+    }
+
+    private static func determineColorCapability() -> TerminalColorCapability {
+        let env = ProcessInfo.processInfo.environment
+
+        // Early returns for special cases
+        if isatty(fileno(stdout)) == 0 {
+            return .dumb
+        }
+
+        if let xcodeService = env["XPC_SERVICE_NAME"], xcodeService.starts(with: "com.apple.dt.Xcode") {
+            return .dumb
+        }
+
+        if let capability = checkCIEnvironment(env) {
+            return capability
+        }
+
+        if let capability = checkTeamCity(env) {
+            return capability
+        }
+
+        if env["COLORTERM"]?.lowercased() == "truecolor" {
+            return .ansi16m
+        }
+
+        if let capability = checkTerminalProgram(env) {
+            return capability
+        }
+
+        if let capability = checkTerminalType(env) {
+            return capability
+        }
+
+        if env["COLORTERM"] != nil {
+            return .ansi16
+        }
+
+        return env["TERM"] == "dumb" ? .dumb : .dumb
+    }
+
+    private static func checkCIEnvironment(
+        _ env: [String: String]
+    ) -> TerminalColorCapability? {
+        guard env["CI"] != nil else { return nil }
+
+        let ciPlatforms = ["TRAVIS", "CIRCLECI", "APPVEYOR", "GITLAB_CI"]
+
+        return ciPlatforms.contains {
+            env[$0] != nil
+        } ? .ansi16 : TerminalColorCapability.dumb
+    }
+
+    private static func checkTeamCity(
+        _ env: [String: String]
+    ) -> TerminalColorCapability? {
+        guard let version = env["TEAMCITY_VERSION"] else {
+            return nil
+        }
+
+        return version.matches("^(9\\.(0*[1-9]\\d*)\\.|\\d{2,}\\.)") ? .ansi16 : TerminalColorCapability.dumb
+    }
+
+    private static func checkTerminalProgram(
+        _ env: [String: String]
+    ) -> TerminalColorCapability? {
+        guard let program = env["TERM_PROGRAM"],
+              let versionString = env["TERM_PROGRAM_VERSION"],
+              let majorVersion = Int(versionString.split(separator: ".").first ?? "") else {
+            return nil
+        }
+
+        switch program {
+            case "iTerm.app":
+                return majorVersion >= 3 ? .ansi16m : .ansi256
+            case "Apple_Terminal":
+                return .ansi256
+            default:
+                return nil
+        }
+    }
+
+    private static func checkTerminalType(
+        _ env: [String: String]
+    ) -> TerminalColorCapability? {
+        guard let term = env["TERM"]?.lowercased() else { return nil }
+
+        if term.matches("-256(color)?$") {
+            return .ansi256
+        }
+
+        let patterns = [
+            "^screen", "^xterm", "^vt100", "^vt220",
+            "^rxvt", "color", "ansi", "cygwin", "linux"
+        ]
+
+        return patterns.contains(where: { $0.matches("-256(color)?$") }) ? .ansi16 : nil
+    }
+}