/*
Language: C#
Author: Jason Diamond <jason@diamond.name>
Contributor: Nicolas LLOBERA <nllobera@gmail.com>, Pieter Vantorre <pietervantorre@gmail.com>, David Pine <david.pine@microsoft.com>
Website: https://docs.microsoft.com/en-us/dotnet/csharp/
Category: common
*/

/** @type LanguageFn */
function csharp(hljs) {
  const BUILT_IN_KEYWORDS = [
    'bool',
    'byte',
    'char',
    'decimal',
    'delegate',
    'double',
    'dynamic',
    'enum',
    'float',
    'int',
    'long',
    'nint',
    'nuint',
    'object',
    'sbyte',
    'short',
    'string',
    'ulong',
    'uint',
    'ushort'
  ];
  const FUNCTION_MODIFIERS = [
    'public',
    'private',
    'protected',
    'static',
    'internal',
    'protected',
    'abstract',
    'async',
    'extern',
    'override',
    'unsafe',
    'virtual',
    'new',
    'sealed',
    'partial'
  ];
  const LITERAL_KEYWORDS = [
    'default',
    'false',
    'null',
    'true'
  ];
  const NORMAL_KEYWORDS = [
    'abstract',
    'as',
    'base',
    'break',
    'case',
    'class',
    'const',
    'continue',
    'do',
    'else',
    'event',
    'explicit',
    'extern',
    'finally',
    'fixed',
    'for',
    'foreach',
    'goto',
    'if',
    'implicit',
    'in',
    'interface',
    'internal',
    'is',
    'lock',
    'namespace',
    'new',
    'operator',
    'out',
    'override',
    'params',
    'private',
    'protected',
    'public',
    'readonly',
    'record',
    'ref',
    'return',
    'sealed',
    'sizeof',
    'stackalloc',
    'static',
    'struct',
    'switch',
    'this',
    'throw',
    'try',
    'typeof',
    'unchecked',
    'unsafe',
    'using',
    'virtual',
    'void',
    'volatile',
    'while'
  ];
  const CONTEXTUAL_KEYWORDS = [
    'add',
    'alias',
    'and',
    'ascending',
    'async',
    'await',
    'by',
    'descending',
    'equals',
    'from',
    'get',
    'global',
    'group',
    'init',
    'into',
    'join',
    'let',
    'nameof',
    'not',
    'notnull',
    'on',
    'or',
    'orderby',
    'partial',
    'remove',
    'select',
    'set',
    'unmanaged',
    'value|0',
    'var',
    'when',
    'where',
    'with',
    'yield'
  ];

  const KEYWORDS = {
    keyword: NORMAL_KEYWORDS.concat(CONTEXTUAL_KEYWORDS),
    built_in: BUILT_IN_KEYWORDS,
    literal: LITERAL_KEYWORDS
  };
  const TITLE_MODE = hljs.inherit(hljs.TITLE_MODE, {
    begin: '[a-zA-Z](\\.?\\w)*'
  });
  const NUMBERS = {
    className: 'number',
    variants: [
      {
        begin: '\\b(0b[01\']+)'
      },
      {
        begin: '(-?)\\b([\\d\']+(\\.[\\d\']*)?|\\.[\\d\']+)(u|U|l|L|ul|UL|f|F|b|B)'
      },
      {
        begin: '(-?)(\\b0[xX][a-fA-F0-9\']+|(\\b[\\d\']+(\\.[\\d\']*)?|\\.[\\d\']+)([eE][-+]?[\\d\']+)?)'
      }
    ],
    relevance: 0
  };
  const VERBATIM_STRING = {
    className: 'string',
    begin: '@"',
    end: '"',
    contains: [
      {
        begin: '""'
      }
    ]
  };
  const VERBATIM_STRING_NO_LF = hljs.inherit(VERBATIM_STRING, {
    illegal: /\n/
  });
  const SUBST = {
    className: 'subst',
    begin: /\{/,
    end: /\}/,
    keywords: KEYWORDS
  };
  const SUBST_NO_LF = hljs.inherit(SUBST, {
    illegal: /\n/
  });
  const INTERPOLATED_STRING = {
    className: 'string',
    begin: /\$"/,
    end: '"',
    illegal: /\n/,
    contains: [
      {
        begin: /\{\{/
      },
      {
        begin: /\}\}/
      },
      hljs.BACKSLASH_ESCAPE,
      SUBST_NO_LF
    ]
  };
  const INTERPOLATED_VERBATIM_STRING = {
    className: 'string',
    begin: /\$@"/,
    end: '"',
    contains: [
      {
        begin: /\{\{/
      },
      {
        begin: /\}\}/
      },
      {
        begin: '""'
      },
      SUBST
    ]
  };
  const INTERPOLATED_VERBATIM_STRING_NO_LF = hljs.inherit(INTERPOLATED_VERBATIM_STRING, {
    illegal: /\n/,
    contains: [
      {
        begin: /\{\{/
      },
      {
        begin: /\}\}/
      },
      {
        begin: '""'
      },
      SUBST_NO_LF
    ]
  });
  SUBST.contains = [
    INTERPOLATED_VERBATIM_STRING,
    INTERPOLATED_STRING,
    VERBATIM_STRING,
    hljs.APOS_STRING_MODE,
    hljs.QUOTE_STRING_MODE,
    NUMBERS,
    hljs.C_BLOCK_COMMENT_MODE
  ];
  SUBST_NO_LF.contains = [
    INTERPOLATED_VERBATIM_STRING_NO_LF,
    INTERPOLATED_STRING,
    VERBATIM_STRING_NO_LF,
    hljs.APOS_STRING_MODE,
    hljs.QUOTE_STRING_MODE,
    NUMBERS,
    hljs.inherit(hljs.C_BLOCK_COMMENT_MODE, {
      illegal: /\n/
    })
  ];
  const STRING = {
    variants: [
      INTERPOLATED_VERBATIM_STRING,
      INTERPOLATED_STRING,
      VERBATIM_STRING,
      hljs.APOS_STRING_MODE,
      hljs.QUOTE_STRING_MODE
    ]
  };

  const GENERIC_MODIFIER = {
    begin: "<",
    end: ">",
    contains: [
      {
        beginKeywords: "in out"
      },
      TITLE_MODE
    ]
  };
  const TYPE_IDENT_RE = hljs.IDENT_RE + '(<' + hljs.IDENT_RE + '(\\s*,\\s*' + hljs.IDENT_RE + ')*>)?(\\[\\])?';
  const AT_IDENTIFIER = {
    // prevents expressions like `@class` from incorrect flagging
    // `class` as a keyword
    begin: "@" + hljs.IDENT_RE,
    relevance: 0
  };

  return {
    name: 'C#',
    aliases: [
      'cs',
      'c#'
    ],
    keywords: KEYWORDS,
    illegal: /::/,
    contains: [
      hljs.COMMENT(
        '///',
        '$',
        {
          returnBegin: true,
          contains: [
            {
              className: 'doctag',
              variants: [
                {
                  begin: '///',
                  relevance: 0
                },
                {
                  begin: '<!--|-->'
                },
                {
                  begin: '</?',
                  end: '>'
                }
              ]
            }
          ]
        }
      ),
      hljs.C_LINE_COMMENT_MODE,
      hljs.C_BLOCK_COMMENT_MODE,
      {
        className: 'meta',
        begin: '#',
        end: '$',
        keywords: {
          keyword: 'if else elif endif define undef warning error line region endregion pragma checksum'
        }
      },
      STRING,
      NUMBERS,
      {
        beginKeywords: 'class interface',
        relevance: 0,
        end: /[{;=]/,
        illegal: /[^\s:,]/,
        contains: [
          {
            beginKeywords: "where class"
          },
          TITLE_MODE,
          GENERIC_MODIFIER,
          hljs.C_LINE_COMMENT_MODE,
          hljs.C_BLOCK_COMMENT_MODE
        ]
      },
      {
        beginKeywords: 'namespace',
        relevance: 0,
        end: /[{;=]/,
        illegal: /[^\s:]/,
        contains: [
          TITLE_MODE,
          hljs.C_LINE_COMMENT_MODE,
          hljs.C_BLOCK_COMMENT_MODE
        ]
      },
      {
        beginKeywords: 'record',
        relevance: 0,
        end: /[{;=]/,
        illegal: /[^\s:]/,
        contains: [
          TITLE_MODE,
          GENERIC_MODIFIER,
          hljs.C_LINE_COMMENT_MODE,
          hljs.C_BLOCK_COMMENT_MODE
        ]
      },
      {
        // [Attributes("")]
        className: 'meta',
        begin: '^\\s*\\[(?=[\\w])',
        excludeBegin: true,
        end: '\\]',
        excludeEnd: true,
        contains: [
          {
            className: 'string',
            begin: /"/,
            end: /"/
          }
        ]
      },
      {
        // Expression keywords prevent 'keyword Name(...)' from being
        // recognized as a function definition
        beginKeywords: 'new return throw await else',
        relevance: 0
      },
      {
        className: 'function',
        begin: '(' + TYPE_IDENT_RE + '\\s+)+' + hljs.IDENT_RE + '\\s*(<.+>\\s*)?\\(',
        returnBegin: true,
        end: /\s*[{;=]/,
        excludeEnd: true,
        keywords: KEYWORDS,
        contains: [
          // prevents these from being highlighted `title`
          {
            beginKeywords: FUNCTION_MODIFIERS.join(" "),
            relevance: 0
          },
          {
            begin: hljs.IDENT_RE + '\\s*(<.+>\\s*)?\\(',
            returnBegin: true,
            contains: [
              hljs.TITLE_MODE,
              GENERIC_MODIFIER
            ],
            relevance: 0
          },
          {
            className: 'params',
            begin: /\(/,
            end: /\)/,
            excludeBegin: true,
            excludeEnd: true,
            keywords: KEYWORDS,
            relevance: 0,
            contains: [
              STRING,
              NUMBERS,
              hljs.C_BLOCK_COMMENT_MODE
            ]
          },
          hljs.C_LINE_COMMENT_MODE,
          hljs.C_BLOCK_COMMENT_MODE
        ]
      },
      AT_IDENTIFIER
    ]
  };
}

module.exports = csharp;
