const CodeMirror = require('codemirror')

CodeMirror.defineMode('nim', function (conf, parserConf) {
  var ERRORCLASS = 'error'

  function wordRegexp(words) {
    return new RegExp('^((' + words.join(')|(') + '))\\b')
  }

  var ops = [
    '=',
    '+',
    '-',
    '*',
    '/',
    '<',
    '>',
    '@',
    '$',
    '~',
    '&',
    '%',
    '|',
    '?',
    '^',
    ':',
    '\\',
    '[',
    ']',
    '(',
    ')',
    ',',
    '{',
    '}',
    '.\\.',
    '.',
  ]
  var operators = new RegExp(
    ops
      .map(function (op) {
        return '\\' + op
      })
      .join('|')
  )
  var identifiers = new RegExp('^[_A-Za-z][_A-Za-z0-9]*')

  var commonkeywords = [
    'addr',
    'asm',
    'atomic',
    'bind',
    'block',
    'break',
    'case',
    'cast',
    'const',
    'continue',
    'converter',
    'discard',
    'distinct',
    'do',
    'elif',
    'else',
    'end',
    'enum',
    'except',
    'export',
    'finally',
    'for',
    'from',
    'generic',
    'if',
    'import',
    'include',
    'interface',
    'iterator',
    'lambda',
    'let',
    'macro',
    'method',
    'mixin',
    'nil',
    'object',
    'out',
    'proc',
    'ptr',
    'raise',
    'ref',
    'return',
    'shared',
    'static',
    'template',
    'try',
    'tuple',
    'type',
    'using',
    'var',
    'when',
    'while',
    'with',
    'without',
    'yield',

    // keyword operators
    'shl',
    'shr',
    'and',
    'or',
    'xor',
    'not',
    'div',
    'mod',
    'is',
    'isnot',
    'in',
    'as',
    'of',
  ]

  var commonBuiltins = [
    'int',
    'int8',
    'int16',
    'int32',
    'int64',
    'uint',
    'uint8',
    'uint16',
    'uint32',
    'uint64',
    'float',
    'float32',
    'float64',
    'bool',
    'char',
    'string',
    'cstring',
    'pointer',
    'range',
    'array',
    'openarray',
    'seq',
    'set',
    'Byte',
    'Natural',
    'Positive',
    'TObject',
    'PObject',
    'Conversion',
    'TResult',
    'TAddress',
    'BiggestInt',
    'BiggestFloat',
    'cchar',
    'cschar',
    'cshort',
    'cint',
    'csize',
    'cuchar',
    'cushort',
    'clong',
    'clonglong',
    'cfloat',
    'cdouble',
    'clongdouble',
    'cuint',
    'culong',
    'culonglong',
    'cchar',
    'cstringArray',
    'TEndian',
    'PFloat32',
    'PFloat64',
    'PInt64',
    'PInt32',
    'TGC_Strategy',
    'TFile',
    'TFileMode',
    'TFileHandle',
    'isMainModule',
    'CompileDate',
    'CompileTime',
    'cpuEndian',
    'hostOS',
    'hostCPU',
    'inf',
    'neginf',
    'nan',
    'QuitSuccess',
    'QuitFailure',
    'dbgLineHook',
    'stdin',
    'stdout',
    'stderr',
    'defined',
    'new',
    'high',
    'low',
    'sizeof',
    'succ',
    'pred',
    'inc',
    'dec',
    'newSeq',
    'len',
    'incl',
    'excl',
    'card',
    'ord',
    'chr',
    'ze',
    'ze64',
    'toU8',
    'toU16',
    'toU32',
    'abs',
    'min',
    'max',
    'add',
    'repr',
    'contains',
    'toFloat',
    'toBiggestFloat',
    'toInt',
    'toBiggestInt',
    'addQuitProc',
    'copy',
    'setLen',
    'newString',
    'zeroMem',
    'copyMem',
    'moveMem',
    'equalMem',
    'alloc',
    'alloc0',
    'realloc',
    'dealloc',
    'setLen',
    'assert',
    'swap',
    'getRefcount',
    'getCurrentException',
    'Msg',
    'getOccupiedMem',
    'getFreeMem',
    'getTotalMem',
    'isNil',
    'seqToPtr',
    'find',
    'pop',
    'GC_disable',
    'GC_enable',
    'GC_fullCollect',
    'GC_setStrategy',
    'GC_enableMarkAnd',
    'Sweep',
    'GC_disableMarkAnd',
    'Sweep',
    'GC_getStatistics',
    'GC_ref',
    'GC_ref',
    'GC_ref',
    'GC_unref',
    'GC_unref',
    'GC_unref',
    'quit',
    'OpenFile',
    'OpenFile',
    'CloseFile',
    'EndOfFile',
    'readChar',
    'FlushFile',
    'readFile',
    'write',
    'readLine',
    'writeln',
    'writeln',
    'getFileSize',
    'ReadBytes',
    'ReadChars',
    'readBuffer',
    'writeBytes',
    'writeChars',
    'writeBuffer',
    'setFilePos',
    'getFilePos',
    'fileHandle',
    'countdown',
    'countup',
    'items',
    'lines',
    'true',
    'false',

    // exceptions
    'E_Base',
    'EAsynch',
    'ESynch',
    'ESystem',
    'EIO',
    'EOS',
    'ERessourceExhausted',
    'EArithmetic',
    'EDivByZero',
    'EOverflow',
    'EAccessViolation',
    'EAssertionFailed',
    'EControlC',
    'EInvalidValue',
    'EOutOfMemory',
    'EInvalidIndex',
    'EInvalidField',
    'EOutOfRange',
    'EStackOverflow',
    'ENoExceptionToReraise',
    'EInvalidObjectAssignment',
    'EInvalidObject',
    'EInvalidLibrary',
    'EInvalidKey',
    'EInvalidObjectConversion',
    'EFloatingPoint',
    'EFloatInvalidOp',
    'EFloatDivByZero',
    'EFloatOverflow',
    'EFloatInexact',
    'EDeadThrea',
  ]

  if (parserConf.extra_keywords != undefined)
    commonkeywords = commonkeywords.concat(parserConf.extra_keywords)

  if (parserConf.extra_builtins != undefined)
    commonBuiltins = commonBuiltins.concat(parserConf.extra_builtins)

  var keywords = wordRegexp(commonkeywords)
  var builtins = wordRegexp(commonBuiltins)

  var indentInfo = null

  var stringPrefixes = new RegExp('^((\'{3}|"{3}|[\'"]))', 'i')

  // tokenizers
  function tokenBase(stream, state) {
    // Handle scope changes
    if (stream.sol()) {
      var scopeOffset = state.scopes[0].offset
      if (stream.eatSpace()) {
        var lineOffset = stream.indentation()
        if (lineOffset > scopeOffset) {
          indentInfo = 'indent'
        } else if (lineOffset < scopeOffset) {
          indentInfo = 'dedent'
        }
        return null
      } else {
        if (scopeOffset > 0) {
          dedent(stream, state)
        }
      }
    }

    if (stream.eatSpace()) return null

    var ch = stream.peek()

    // Handle Comments
    if (ch === '#') {
      stream.skipToEnd()
      return 'comment'
    }

    // Handle Number Literals
    if (stream.match(/^[0-9.]/, false)) {
      var floatLiteral = false
      // Floats
      if (stream.match(/^\d*\.\d+(e[+-]?\d+)?/i)) {
        floatLiteral = true
      }
      if (stream.match(/^\d+\.\d*/)) {
        floatLiteral = true
      }
      if (stream.match(/^\.\d+/)) {
        floatLiteral = true
      }
      if (floatLiteral) {
        // Float literals may be "imaginary"
        stream.eat(/J/i)
        return 'number'
      }
      // Integers
      var intLiteral = false
      // Hex
      if (stream.match(/^0x[0-9a-f]+/i)) {
        intLiteral = true
      }
      // Binary
      if (stream.match(/^0b[01]+/i)) {
        intLiteral = true
      }
      // Octal
      if (stream.match(/^0o[0-7]+/i)) {
        intLiteral = true
      }
      // Decimal
      if (stream.match(/^[1-9]\d*(e[+-]?\d+)?/)) {
        // Decimal literals may be "imaginary"
        stream.eat(/J/i)
        intLiteral = true
      }
      // Zero by itself with no other piece of number.
      if (stream.match(/^0(?![\dx])/i)) {
        intLiteral = true
      }
      if (intLiteral) {
        // Integer literals may be "long"
        stream.eat(/L/i)
        return 'number'
      }
    }

    // Handle Strings
    if (stream.match(stringPrefixes)) {
      state.tokenize = tokenStringFactory(stream.current())
      return state.tokenize(stream, state)
    }

    if (stream.match(operators)) return 'operator'

    if (stream.match(keywords)) return 'keyword'

    if (stream.match(builtins)) return 'builtin'

    if (stream.match(identifiers)) {
      if (
        state.lastToken != null &&
        state.lastToken.match(/proc|iterator|macro|template|class|converter/)
      ) {
        return 'def'
      }

      return 'variable'
    }

    // Handle non-detected items
    stream.next()
    return ERRORCLASS
  }

  function tokenStringFactory(delimiter) {
    var singleline = delimiter.length == 1
    var OUTCLASS = 'string'

    function tokenString(stream, state) {
      while (!stream.eol()) {
        stream.eatWhile(/[^'"\\]/)
        if (stream.eat('\\')) {
          stream.next()
          if (singleline && stream.eol()) {
            return OUTCLASS
          }
        } else if (stream.match(delimiter)) {
          state.tokenize = tokenBase
          return OUTCLASS
        } else {
          stream.eat(/['"]/)
        }
      }
      if (singleline) {
        if (parserConf.singleLineStringErrors) {
          return ERRORCLASS
        } else {
          state.tokenize = tokenBase
        }
      }
      return OUTCLASS
    }

    tokenString.isString = true
    return tokenString
  }

  function indent(stream, state, type) {
    type = type || 'nim'
    var indentUnit = 0
    if (type === 'nim') {
      if (state.scopes[0].type !== 'nim') {
        state.scopes[0].offset = stream.indentation()
        return
      }
      for (var i = 0; i < state.scopes.length; ++i) {
        if (state.scopes[i].type === 'nim') {
          indentUnit = state.scopes[i].offset + conf.indentUnit
          break
        }
      }
    } else {
      indentUnit = stream.column() + stream.current().length
    }

    state.scopes.unshift({
      offset: indentUnit,
      type: type,
    })
  }

  function dedent(stream, state, type) {
    type = type || 'nim'
    if (state.scopes.length == 1) return
    if (state.scopes[0].type === 'nim') {
      var _indent = stream.indentation()
      var _indent_index = -1
      for (var i = 0; i < state.scopes.length; ++i) {
        if (_indent === state.scopes[i].offset) {
          _indent_index = i
          break
        }
      }
      if (_indent_index === -1) {
        return true
      }
      while (state.scopes[0].offset !== _indent) {
        state.scopes.shift()
      }
      return false
    } else {
      if (type === 'nim') {
        state.scopes[0].offset = stream.indentation()
        return false
      } else {
        if (state.scopes[0].type != type) {
          return true
        }
        state.scopes.shift()
        return false
      }
    }
  }

  function tokenLexer(stream, state) {
    indentInfo = null
    var style = state.tokenize(stream, state)
    var current = stream.current()

    // Handle '.' connected identifiers
    if (current === '.') {
      style = stream.match(identifiers, false) ? null : ERRORCLASS
      if (style === null && state.lastStyle === 'meta') {
        // Apply 'meta' style to '.' connected identifiers when
        // appropriate.
        style = 'meta'
      }
      return style
    }

    if ((style === 'variable' || style === 'builtin') && state.lastStyle === 'meta') {
      style = 'meta'
    }

    // Handle scope changes.
    if (current.match(/return|break|continue|raise/) || (current === 'discard' && stream.eol()))
      state.dedent += 1

    if (current === 'lambda' || current === 'proc') state.lambda = true

    var delimiter_index = '[({'.indexOf(current)

    if (delimiter_index !== -1) {
      indent(stream, state, '])}'.slice(delimiter_index, delimiter_index + 1))
    } else if (stream.eol() && current.match(/=|:|import|include|type|const|var|let/)) {
      indent(stream, state)
    }

    if (indentInfo === 'dedent') {
      if (dedent(stream, state)) {
        return ERRORCLASS
      }
    }

    delimiter_index = '])}'.indexOf(current)
    if (delimiter_index !== -1) {
      if (dedent(stream, state, current)) {
        return ERRORCLASS
      }
    }

    if (state.dedent > 0 && stream.eol() && state.scopes[0].type == 'nim') {
      if (state.scopes.length > 1) state.scopes.shift()
      state.dedent -= 1
    }

    return style
  }

  var external = {
    startState: function (basecolumn) {
      return {
        tokenize: tokenBase,
        scopes: [{ offset: basecolumn || 0, type: 'nim' }],
        lastStyle: null,
        lastToken: null,
        lambda: false,
        dedent: 0,
      }
    },

    token: function (stream, state) {
      var style = tokenLexer(stream, state)

      state.lastStyle = style

      var current = stream.current()
      if (current && style) state.lastToken = current

      if (stream.eol() && state.lambda) state.lambda = false

      return style
    },

    indent: function (state) {
      if (state.tokenize != tokenBase) return state.tokenize.isString ? CodeMirror.Pass : 0

      return state.scopes[0].offset
    },

    lineComment: '#',
    fold: 'indent',
  }

  return external
})

CodeMirror.defineMIME('text/x-nim', 'nim')