/// Default environment for PTY-spawned children.
///
/// `xterm.dart` on the UI side + most shells + tmux + Claude CLI all
/// understand the 24-bit-colour triplet `TERM=xterm-256color` +
/// `COLORTERM=truecolor`. Without `COLORTERM` most apps fall back to
/// the 256-colour palette and the terminal looks washed out even though
/// the renderer can do true colour.
library;

/// Base env clide's daemon builds for every PTY child. Callers merge
/// with the user's environment before passing to `ptyc` — a child that
/// needs user env like `HOME` / `USER` / `SHELL` still gets them; the
/// keys here override the ones the child cares about.
const Map<String, String> clidePtyEnvDefaults = {
  'TERM': 'xterm-256color',
  'COLORTERM': 'truecolor',
  // Encourages 24-bit emission from tooling that checks this:
  'CLICOLOR_FORCE': '1',
  // tmux inherits these when clide spawns tmux; safe to propagate.
  'LANG': 'en_US.UTF-8',
  'LC_ALL': 'en_US.UTF-8',
};

/// Merge [base] onto the process environment; clide defaults override
/// user env where they overlap. Explicit [overrides] win over both.
Map<String, String> mergePtyEnv({
  required Map<String, String> processEnv,
  Map<String, String>? overrides,
}) {
  return {
    ...processEnv,
    ...clidePtyEnvDefaults,
    if (overrides != null) ...overrides,
  };
}