/**
 * @file Tumblr grammar for tree-sitter
 * @author Oscar Wallberg <oscar.wallberg@outlook.com>
 * @license Apache-2.0
 */

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

export default grammar({
  name: "tumblr",

  extras: _ => [],

  rules: {
    template: $ => repeat($._node),

    _node: $ => choice(
      $.content,
      $.block_open,
      $.block_close,
      $.lang_tag,
      $.variable,
    ),

    content: _ => token(prec(-1, /([^{]|\{[^A-Za-z/])+/)),

    block_open: $ => seq(
      $._block_open_start,
      $.block_name,
      optional($.attributes),
      "}",
    ),

    block_close: $ => seq(
      $._block_close_start,
      $.block_name,
      "}",
    ),

    lang_tag: $ => seq(
      $._lang_start,
      $.lang_text,
      "}",
    ),

    variable: $ => seq(
      "{",
      choice(
        seq($.variable_name, optional(seq("-", $.variable_modifier))),
        seq($.variable_prefix, ":", $.prefix_argument),
      ),
      "}",
    ),

    attributes: $ => repeat1($.attribute),
    attribute: $ => seq($._space, $.attribute_name, "=", $.attribute_value),
    attribute_name: _ => /[A-Za-z_][A-Za-z0-9_-]*/,
    attribute_value: _ => /"[^"]*"/,

    block_name: _ => /[A-Za-z][A-Za-z0-9_]*/,
    variable_name: _ => /[A-Z][A-Za-z0-9_]*/,
    variable_modifier: _ => /[A-Za-z0-9]+/,
    variable_prefix: _ => choice("text", "color", "font", "image"),
    prefix_argument: _ => /[A-Za-z][A-Za-z0-9 _-]*/,
    lang_text: _ => /[^}]+/,

    _block_open_start: _ => /\{[Bb][Ll][Oo][Cc][Kk]:/,
    _block_close_start: _ => /\{\/[Bb][Ll][Oo][Cc][Kk]:/,
    _lang_start: _ => /\{[Ll][Aa][Nn][Gg]:/,
    _space: _ => /[ \t]+/,
  },
});