export const languageConfiguration = {
  wordPattern: /(-?\d*\.\d\w*)|([^\`\~\!\@\#\%\^\&\*\(\)\-\=\+\[\{\]\}\\\|\;\:\'\"\,\.\<\>\/\?\s]+)/g,
  comments: {
    lineComment: '--',
    blockComment: ['/*', '*/'] as [string, string],
  },
  brackets: [
    ['{', '}'],
    ['[', ']'],
    ['(', ')'],
  ] as any,
  autoClosingPairs: [
    { open: '{', close: '}' },
    { open: '[', close: ']' },
    { open: '(', close: ')' },
    { open: '"', close: '"' },
    { open: "'", close: "'" },
    { open: '`', close: '`' },
  ] as any,
  surroundingPairs: [
    { open: '{', close: '}' },
    { open: '[', close: ']' },
    { open: '(', close: ')' },
    { open: '"', close: '"' },
    { open: "'", close: "'" },
    { open: '`', close: '`' },
  ] as any,
  folding: {
    offSide: false,
  },
};

// SQL keywords
const keywords = [
  'SELECT',
  'FROM',
  'WHERE',
  'AND',
  'OR',
  'NOT',
  'JOIN',
  'INNER',
  'LEFT',
  'RIGHT',
  'FULL',
  'OUTER',
  'ON',
  'ORDER',
  'BY',
  'GROUP',
  'HAVING',
  'LIMIT',
  'OFFSET',
  'INSERT',
  'INTO',
  'VALUES',
  'UPDATE',
  'SET',
  'DELETE',
  'CREATE',
  'TABLE',
  'ALTER',
  'DROP',
  'PRIMARY',
  'KEY',
  'FOREIGN',
  'CONSTRAINT',
  'UNIQUE',
  'INDEX',
  'VIEW',
  'DATABASE',
  'SCHEMA',
  'AS',
  'DISTINCT',
  'CASE',
  'WHEN',
  'THEN',
  'ELSE',
  'END',
  'CAST',
  'BETWEEN',
  'IN',
  'LIKE',
  'IS',
  'NULL',
  'TRUE',
  'FALSE',
  'WITH',
  'UNION',
  'EXCEPT',
  'INTERSECT',
];

export const language = {
  defaultToken: '',
  tokenPostfix: '.sql',
  ignoreCase: true,

  brackets: [
    { open: '(', close: ')', token: 'delimiter.parenthesis' },
    { open: '{', close: '}', token: 'delimiter.curly' },
    { open: '[', close: ']', token: 'delimiter.square' },
  ],

  keywords,

  operators: ['=', '>', '<', '!', '%', '&', '|', '^', '~', '?', ':', '+', '-', '*', '/'],

  builtinFunctions: [
    'COUNT',
    'SUM',
    'AVG',
    'MIN',
    'MAX',
    'UPPER',
    'LOWER',
    'LENGTH',
    'SUBSTRING',
    'TRIM',
    'ROUND',
    'ABS',
    'COALESCE',
    'NULLIF',
    'IFNULL',
    'CONCAT',
    'DATE',
    'NOW',
    'YEAR',
    'MONTH',
    'DAY',
    'HOUR',
    'MINUTE',
    'SECOND',
  ],

  escapes: /\\(?:[abfnrtv\\"']|x[0-9A-Fa-f]{1,4}|u[0-9A-Fa-f]{4}|U[0-9A-Fa-f]{8})/,

  digits: /\d+(_+\d+)*/,

  octaldigits: /[0-7]+(_+[0-7]+)*/,

  hexdigits: /[[0-9a-fA-F]+(_+[0-9a-fA-F]+)*/,

  regexpctl: /[(){}\[\]\|;,.?*+^$\\]/,

  regexpattern: /(\{[0-9]+\})|(\{[0-9]*,[0-9]*\})|(\?(?:\?)?|[*+]|\^|\$|\|\\)/,

  tokenizer: {
    root: [
      { include: '@comments' },
      { include: '@whitespace' },
      { include: '@pseudo-columns' },
      [/[;,.]/, 'delimiter'],
      [/[{}()\[\]]/, '@brackets'],
      { include: '@builtinVariables' },
      { include: '@numbers' },
      { include: '@strings' },
      [/[a-zA-Z_#][a-zA-Z0-9_$#@]*(?=\s*\()/, { cases: { '@builtinFunctions': 'keyword.function', '@default': 'identifier.function' } }],
      [
        /[a-zA-Z_#][a-zA-Z0-9_$#@]*/,
        {
          cases: {
            '@keywords': 'keyword',
            '@default': 'identifier',
          },
        },
      ],
      [/[<>=!%&+\-*/|~^]/, 'operator'],
    ],

    whitespace: [[/\s+/, 'white']],

    comments: [
      [/--+.*/, 'comment'],
      [/\/\*/, { token: 'comment.quote', next: '@comment' }],
    ],

    comment: [
      [/[^*/]+/, 'comment'],
      [/\*\//, { token: 'comment.quote', next: '@pop' }],
      [/./, 'comment'],
    ],

    'pseudo-columns': [
      [
        /[$][A-Za-z_][A-Za-z0-9_]*/,
        {
          cases: {
            '@keywords': 'keyword',
            '@default': 'variable',
          },
        },
      ],
      [
        /@[A-Za-z_][A-Za-z0-9_]*/,
        {
          cases: {
            '@keywords': 'keyword',
            '@default': 'variable',
          },
        },
      ],
    ],

    builtinVariables: [
      [
        /@@?[a-zA-Z_][a-zA-Z0-9_]*/,
        {
          cases: {
            '@keywords': 'keyword',
            '@default': 'variable',
          },
        },
      ],
    ],

    numbers: [
      [/0[xX][0-9a-fA-F]*[0-9a-fA-F]/, 'number.hex'],
      [/0[0-7]+(?!\d)/, 'number.octal'],
      [/(\d+(\.\d*)?|\.\d+)([eE][+-]?\d+)?/, 'number'],
    ],

    strings: [
      [/'/, { token: 'string', next: '@string' }],
      [/"/, { token: 'string.double', next: '@string_double' }],
      [/`/, { token: 'string.backtick', next: '@string_backtick' }],
    ],

    string: [
      [/[^'\\]+/, 'string'],
      [/@escapes/, 'string.escape'],
      [/\\./, 'string.escape.invalid'],
      [/'/, { token: 'string', next: '@pop' }],
    ],

    string_double: [
      [/[^"\\]+/, 'string.double'],
      [/@escapes/, 'string.escape'],
      [/\\./, 'string.escape.invalid'],
      [/"/, { token: 'string.double', next: '@pop' }],
    ],

    string_backtick: [
      [/[^`\\]+/, 'string.backtick'],
      [/@escapes/, 'string.escape'],
      [/\\./, 'string.escape.invalid'],
      [/`/, { token: 'string.backtick', next: '@pop' }],
    ],
  },
};