/// <reference types="tree-sitter-cli/dsl" />
// @ts-check

module.exports = grammar({
  name: "noil",

  extras: $ => [
    /[ \t]+/, // skip whitespace but not newlines
  ],

  rules: {
    source_file: $ => repeat($.line),

    line: $ => choice(
      $.operation_line,
      $.operation_only_line,
      $.mapping_line,
      $.path_only_line,
      $.empty_line
    ),

    empty_line: _ => "\n",

    path_only_line: $ => seq(
      ":",
      field("path", $.file_path),
      "\n"
    ),

    mapping_line: $ => seq(
      field("prefix", $.prefix),
      ":",
      field("path", $.file_path),
      "\n"
    ),

    operation_line: $ => seq(
      field("operation", $.operation),
      field("prefix", $.prefix),
      ":",
      field("path", $.file_path),
      "\n"
    ),

    operation_only_line: $ => seq(
      field("operation", $.operation),
      ":",
      field("path", $.file_path),
      "\n"
    ),

    prefix: _ => /[a-z0-9]+/,           // allow lowercase alphanumeric
    file_path: _ => /[^ \t\n][^\n]*/,   // must not start with space or newline
    operation: $ => choice(
      $.op_add,
      $.op_delete,
      $.op_move,
      $.op_copy,
      $.generic_operation
    ),
    
    op_add: _ => choice("A", "ADD"),
    op_delete: _ => choice("D", "DELETE"),
    op_move: _ => choice("M", "MV", "MOVE", "RENAME"),
    op_copy: _ => choice("C","COPY"),
    generic_operation: _ => /[A-Z]+/,
  }
});