// Prism syntax highlighting referenced from Refractor
// https://github.com/wooorm/refractor/blob/main/lang/dart.js

export function dart(Prism: any) {
  // Handles named imports, such as http.Client
  const keywords = [
    /\b(?:async|sync|yield)\*/,
    /\b(?:abstract|assert|async|await|break|case|catch|class|const|continue|covariant|default|deferred|do|dynamic|else|enum|export|extends|extension|external|factory|final|finally|for|get|hide|if|implements|import|in|interface|library|mixin|new|null|on|operator|part|rethrow|return|set|show|static|super|switch|sync|this|throw|try|typedef|var|void|while|with|yield)\b/,
  ]

  // based on the dart naming conventions
  const packagePrefix = /(^|[^\w.])(?:[a-z]\w*\s*\.\s*)*(?:[A-Z]\w*\s*\.\s*)*/.source

  const className = {
    pattern: RegExp(packagePrefix + /[A-Z](?:[\d_A-Z]*[a-z]\w*)?\b/.source),
    lookbehind: true,
    inside: {
      namespace: {
        pattern: /^[a-z]\w*(?:\s*\.\s*[a-z]\w*)*(?:\s*\.)?/,
        inside: {
          punctuation: /\./,
        },
      },
    },
  }

  Prism.languages.dart = Prism.languages.extend('clike', {
    'class-name': [
      className,
      {
        // variables and parameters
        // supports class names (or generic parameters) which do not contain a lower case letter (also works for methods)
        pattern: RegExp(packagePrefix + /[A-Z]\w*(?=\s+\w+\s*[;,=()])/.source),
        lookbehind: true,
        inside: className.inside,
      },
    ],
    keyword: keywords,
    operator: /\bis!|\b(?:as|is)\b|\+\+|--|&&|\|\||<<=?|>>=?|~(?:\/=?)?|[+\-*\/%&^|=!<>]=?|\?/,
  })
  Prism.languages.insertBefore('dart', 'string', {
    'string-literal': {
      pattern: /r?(?:("""|''')[\s\S]*?\1|(["'])(?:\\.|(?!\2)[^\\\r\n])*\2(?!\2))/,
      greedy: true,
      inside: {
        interpolation: {
          pattern: /((?:^|[^\\])(?:\\{2})*)\$(?:\w+|\{(?:[^{}]|\{[^{}]*\})*\})/,
          lookbehind: true,
          inside: {
            punctuation: /^\$\{?|\}$/,
            expression: {
              pattern: /[\s\S]+/,
              inside: Prism.languages.dart,
            },
          },
        },
        string: /[\s\S]+/,
      },
    },
    string: undefined,
  })
  Prism.languages.insertBefore('dart', 'class-name', {
    metadata: {
      pattern: /@\w+/,
      alias: 'function',
    },
  })
  Prism.languages.insertBefore('dart', 'class-name', {
    generics: {
      pattern: /<(?:[\w\s,.&?]|<(?:[\w\s,.&?]|<(?:[\w\s,.&?]|<[\w\s,.&?]*>)*>)*>)*>/,
      inside: {
        'class-name': className,
        keyword: keywords,
        punctuation: /[<>(),.:]/,
        operator: /[?&|]/,
      },
    },
  })
}