module.exports = grammar({
  name: 'nixshell',

  rules: {
    source_file: $ => seq($.first_line, repeat($.next_line)),

    first_line: $ => seq($.shebang_open, $.opt_ws, optional(seq($.env, $.ws)), $.nix_shell),
    next_line: $ => seq($.newline, choice(
        $.annotation_line,
        // TODO: capture this
        repeat(/./),
    )),
    annotation_line: $ => seq($.shebang_open, $.opt_ws, $.nix_shell, $.nix_shell_args),
    // payload_next_line: $ => /\n.*/,
    // payload_line: $ => /.*/,
    // payload_line: $ => repeat(/./),

    // nix_shell_directive_open: $ => '#!nix-shell',
    // TODO: actually parse nix-shell arguments
    nix_shell_args: $ => ' -i bash',

    // TODO: hide these (prefix with underscore)
    shebang_open: $ => '#!',
    // TODO: allow `usr/bin/env`, `env`
    env: $ => '/usr/bin/env',
    nix_shell: $ => 'nix-shell',
    ws: $ => / +/,
    opt_ws: $ => / */,
    newline: $ => '\n',
  }
});