@preprocessor urichk

@{%
  import moo from "https://deno.land/x/moo@0.5.1.1/index.ts";
  const commonTokenRules = {
    num: /[0-9]+/,
    ln: { match: /\r?\n/, lineBreaks: true },
    ws: /[ \t]+/,
    id: /(?:[a-zA-Z0-9\-._~]|%[0-9a-fA-F]{2})+/,
    sc: /\/\/[^\r\n]*\r?\n/,
    mc: /\/\*(?:\*(?!\/)|[^*])*\*\//,
  };
  const lexer = moo.states({
    root: {
      ...commonTokenRules,
      lcb: { match: '{', push: 'block' },
      reserved: /[:/?#\[\]@]/,
      permitted: /[!$&'()*+,;=]/,
    },
    block: {
      ...commonTokenRules,
      lcb: { match: '{', push: 'block' },
      rcb: { match: '}', pop: 1 },
      string: /'.*?'/,
      symbol: /[?#:'=|\[\]]/,
      regex: /\/(?:(?![*+?])(?:[^\r\n\[/\\]|\\.|\[(?:[^\r\n\]\\]|\\.)*\])+)\/[a-z]*/,
    },
  });
%}
@lexer lexer

urichk -> rule:* _ {% id %}
_ -> (%ws | %ln | %sc | %mc):* {%
  ([tokens]) => {
    let result = undefined;
    for (const [token] of tokens) {
      if (token.type === 'mc') result = token;
    }
    return result;
  }
%}
ident => %id {% id %} | %num {% id %}

rule -> _ head _ tail {% ([comment, head, , tail]) => ({ comment, head, tail }) %}

head ->
    scheme authority path:? {% parseHead %}
  | scheme:? authority:? path {% parseHead %}
@{%
  const parseHead = ([scheme, authority, path]) => ({
    scheme,
    authority,
    path,
  });
%}

tail -> "{" (_ tail_rule):* _ "}" {% ([, rules]) => rules.map(([comment, rule]) => ({ comment, ...rule })) %}

scheme -> ident ":" {% id %}
authority ->
  ("/" "/"):? userinfo:? ident port:?
  {% ([, userinfo, host, port]) => ({
    userinfo,
    host,
    port,
  }) %}
userinfo -> ident "@" {% id %}
host -> ident {% id %}
port -> ":" %num {% ([, port]) => port %}
path ->
    "/" {% () => [] %}
  | ("/" path_fragment):+ "/":? {% ([fragments]) => fragments.map(([, fragment]) => fragment) %}
path_fragment ->
    ident {% ([name]) => ({ type: 'static', name }) %}
  | "[" _ ident _ "]" {% ([, , name]) => ({ type: 'param', name }) %}

tail_rule ->
    tail_rule_match {% id %}
  | tail_rule_form {% id %}
tail_rule_tail_type ->
    "?" {% id %}
  | "#" {% id %}
tail_rule_match ->
  tail_rule_tail_type _ "match" _ tail_rule_pattern_value {% ([tailType, , matchType, , pattern]) => ({
    tailType,
    matchType,
    pattern,
  }) %}
tail_rule_form ->
  tail_rule_tail_type _ "form" _ tail_rule_form_pattern {% ([tailType, , matchType, , pattern]) => ({
    tailType,
    matchType,
    pattern,
  }) %}
tail_rule_form_pattern -> "{" (_ tail_rule_form_pattern_rule):* _ "}" {% ([, rules]) => rules.map(([comment, rule]) => ({ comment, ...rule })) %}
tail_rule_form_pattern_rule ->
    tail_rule_form_pattern_rule_key {% ([key]) => ({ key, value: null, array: false }) %}
  | tail_rule_form_pattern_rule_key _ "=" _ tail_rule_pattern_value
  {% ([key, /*_*/, /*"="*/, /*_*/, value]) => ({
    key,
    value,
    array: false,
  }) %}
  | tail_rule_form_pattern_rule_key _ "[" _ "]" _ "=" _ tail_rule_pattern_value
  {% ([key, /*_*/, /*[*/, /*_*/, /*]*/, /*_*/, /*"="*/, /*_*/, value]) => ({
    key,
    value,
    array: true,
  }) %}
tail_rule_form_pattern_rule_key ->
    ident {% ([value]) => ({ type: 'id', value }) %}
  | %string {% ([value]) => ({ type: 'string', value }) %}
tail_rule_pattern_value ->
  ("|" _):? (tail_rule_pattern_value_term _ "|" _):* tail_rule_pattern_value_term
  {% ([, rules, rule]) => [...rules.map(([rule]) => rule), rule] %}
tail_rule_pattern_value_term ->
    ident {% ([value]) => ({ type: 'id', value }) %}
  | %string {% ([value]) => ({ type: 'string', value }) %}
  | %regex {% ([value]) => ({ type: 'regex', value }) %}