// CodeMirror, copyright (c) by Marijn Haverbeke and others
// Distributed under an MIT license: http://codemirror.net/LICENSE

;(function (mod) {
    if (typeof exports == 'object' && typeof module == 'object')
        // CommonJS
        mod(require('../../lib/codemirror'))
    else if (typeof define == 'function' && define.amd)
        // AMD
        define(['../../lib/codemirror'], mod)
    // Plain browser env
    else mod(CodeMirror)
})(function (CodeMirror) {
    'use strict'

    CodeMirror.defineMode('elm', function () {
        function switchState(source, setState, f) {
            setState(f)
            return f(source, setState)
        }

        var lowerRE = /[a-z]/
        var upperRE = /[A-Z]/
        var innerRE = /[a-zA-Z0-9_]/

        var digitRE = /[0-9]/
        var hexRE = /[0-9A-Fa-f]/
        var symbolRE = /[-&*+.\\/<>=?^|:]/
        var specialRE = /[(),[\]{}]/
        var spacesRE = /[ \v\f]/ // newlines are handled in tokenizer

        function normal() {
            return function (source, setState) {
                if (source.eatWhile(spacesRE)) {
                    return null
                }

                var char = source.next()

                if (specialRE.test(char)) {
                    return char === '{' && source.eat('-')
                        ? switchState(source, setState, chompMultiComment(1))
                        : char === '[' && source.match('glsl|')
                        ? switchState(source, setState, chompGlsl)
                        : 'builtin'
                }

                if (char === "'") {
                    return switchState(source, setState, chompChar)
                }

                if (char === '"') {
                    return source.eat('"') ? (source.eat('"') ? switchState(source, setState, chompMultiString) : 'string') : switchState(source, setState, chompSingleString)
                }

                if (upperRE.test(char)) {
                    source.eatWhile(innerRE)
                    return 'variable-2'
                }

                if (lowerRE.test(char)) {
                    var isDef = source.pos === 1
                    source.eatWhile(innerRE)
                    return isDef ? 'def' : 'variable'
                }

                if (digitRE.test(char)) {
                    if (char === '0') {
                        if (source.eat(/[xX]/)) {
                            source.eatWhile(hexRE) // should require at least 1
                            return 'number'
                        }
                    } else {
                        source.eatWhile(digitRE)
                    }
                    if (source.eat('.')) {
                        source.eatWhile(digitRE) // should require at least 1
                    }
                    if (source.eat(/[eE]/)) {
                        source.eat(/[-+]/)
                        source.eatWhile(digitRE) // should require at least 1
                    }
                    return 'number'
                }

                if (symbolRE.test(char)) {
                    if (char === '-' && source.eat('-')) {
                        source.skipToEnd()
                        return 'comment'
                    }
                    source.eatWhile(symbolRE)
                    return 'keyword'
                }

                if (char === '_') {
                    return 'keyword'
                }

                return 'error'
            }
        }

        function chompMultiComment(nest) {
            if (nest == 0) {
                return normal()
            }
            return function (source, setState) {
                while (!source.eol()) {
                    var char = source.next()
                    if (char == '{' && source.eat('-')) {
                        ++nest
                    } else if (char == '-' && source.eat('}')) {
                        --nest
                        if (nest === 0) {
                            setState(normal())
                            return 'comment'
                        }
                    }
                }
                setState(chompMultiComment(nest))
                return 'comment'
            }
        }

        function chompMultiString(source, setState) {
            while (!source.eol()) {
                var char = source.next()
                if (char === '"' && source.eat('"') && source.eat('"')) {
                    setState(normal())
                    return 'string'
                }
            }
            return 'string'
        }

        function chompSingleString(source, setState) {
            while (source.skipTo('\\"')) {
                source.next()
                source.next()
            }
            if (source.skipTo('"')) {
                source.next()
                setState(normal())
                return 'string'
            }
            source.skipToEnd()
            setState(normal())
            return 'error'
        }

        function chompChar(source, setState) {
            while (source.skipTo("\\'")) {
                source.next()
                source.next()
            }
            if (source.skipTo("'")) {
                source.next()
                setState(normal())
                return 'string'
            }
            source.skipToEnd()
            setState(normal())
            return 'error'
        }

        function chompGlsl(source, setState) {
            while (!source.eol()) {
                var char = source.next()
                if (char === '|' && source.eat(']')) {
                    setState(normal())
                    return 'string'
                }
            }
            return 'string'
        }

        var wellKnownWords = {
            case: 1,
            of: 1,
            as: 1,
            if: 1,
            then: 1,
            else: 1,
            let: 1,
            in: 1,
            type: 1,
            alias: 1,
            module: 1,
            where: 1,
            import: 1,
            exposing: 1,
            port: 1,
        }

        return {
            startState: function () {
                return { f: normal() }
            },
            copyState: function (s) {
                return { f: s.f }
            },

            token: function (stream, state) {
                var type = state.f(stream, function (s) {
                    state.f = s
                })
                var word = stream.current()
                return wellKnownWords.hasOwnProperty(word) ? 'keyword' : type
            },
        }
    })

    CodeMirror.defineMIME('text/x-elm', 'elm')
})