// ABNF grammar:
// https://github.com/dhall-lang/dhall-lang/blob/master/standard/dhall.abnf

Prism.languages.dhall = {
  // Multi-line comments can be nested. E.g. {- foo {- bar -} -}
  // The multi-line pattern is essentially this:
  //   \{-(?:[^-{]|-(?!\})|\{(?!-)|<SELF>)*-\}
  comment:
    /--.*|\{-(?:[^-{]|-(?!\})|\{(?!-)|\{-(?:[^-{]|-(?!\})|\{(?!-))*-\})*-\}/,
  string: {
    pattern: /"(?:[^"\\]|\\.)*"|''(?:[^']|'(?!')|'''|''\$\{)*''(?!'|\$)/,
    greedy: true,
    inside: {
      interpolation: {
        pattern: /\$\{[^{}]*\}/,
        inside: {
          expression: {
            pattern: /(^\$\{)[\s\S]+(?=\}$)/,
            lookbehind: true,
            alias: 'language-dhall',
            inside: null, // see blow
          },
          punctuation: /\$\{|\}/,
        },
      },
    },
  },
  label: {
    pattern: /`[^`]*`/,
    greedy: true,
  },
  url: {
    // https://github.com/dhall-lang/dhall-lang/blob/5fde8ef1bead6fb4e999d3c1ffe7044cd019d63a/standard/dhall.abnf#L596
    pattern:
      /\bhttps?:\/\/[\w.:%!$&'*+;=@~-]+(?:\/[\w.:%!$&'*+;=@~-]*)*(?:\?[/?\w.:%!$&'*+;=@~-]*)?/,
    greedy: true,
  },
  env: {
    // https://github.com/dhall-lang/dhall-lang/blob/5fde8ef1bead6fb4e999d3c1ffe7044cd019d63a/standard/dhall.abnf#L661
    pattern: /\benv:(?:(?!\d)\w+|"(?:[^"\\=]|\\.)*")/,
    greedy: true,
    inside: {
      function: /^env/,
      operator: /^:/,
      variable: /[\s\S]+/,
    },
  },
  hash: {
    // https://github.com/dhall-lang/dhall-lang/blob/5fde8ef1bead6fb4e999d3c1ffe7044cd019d63a/standard/dhall.abnf#L725
    pattern: /\bsha256:[\da-fA-F]{64}\b/,
    inside: {
      function: /sha256/,
      operator: /:/,
      number: /[\da-fA-F]{64}/,
    },
  },

  // https://github.com/dhall-lang/dhall-lang/blob/5fde8ef1bead6fb4e999d3c1ffe7044cd019d63a/standard/dhall.abnf#L359
  keyword:
    /\b(?:as|assert|else|forall|if|in|let|merge|missing|then|toMap|using|with)\b|\u2200/,
  builtin: /\b(?:None|Some)\b/,

  boolean: /\b(?:False|True)\b/,
  number:
    /\bNaN\b|-?\bInfinity\b|[+-]?\b(?:0x[\da-fA-F]+|\d+(?:\.\d+)?(?:e[+-]?\d+)?)\b/,
  operator:
    /\/\\|\/\/\\\\|&&|\|\||===|[!=]=|\/\/|->|\+\+|::|[+*#@=:?<>|\\\u2227\u2a53\u2261\u2afd\u03bb\u2192]/,
  punctuation: /\.\.|[{}\[\](),./]/,

  // we'll just assume that every capital word left is a type name
  'class-name': /\b[A-Z]\w*\b/,
};

Prism.languages.dhall.string.inside.interpolation.inside.expression.inside =
  Prism.languages.dhall;