// CodeMirror, copyright (c) by Marijn Haverbeke and others
// Distributed under an MIT license: https://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('ebnf', function (config) {
        var commentType = { slash: 0, parenthesis: 1 }
        var stateType = { comment: 0, _string: 1, characterClass: 2 }
        var bracesMode = null

        if (config.bracesMode) bracesMode = CodeMirror.getMode(config, config.bracesMode)

        return {
            startState: function () {
                return {
                    stringType: null,
                    commentType: null,
                    braced: 0,
                    lhs: true,
                    localState: null,
                    stack: [],
                    inDefinition: false,
                }
            },
            token: function (stream, state) {
                if (!stream) return

                //check for state changes
                if (state.stack.length === 0) {
                    //strings
                    if (stream.peek() == '"' || stream.peek() == "'") {
                        state.stringType = stream.peek()
                        stream.next() // Skip quote
                        state.stack.unshift(stateType._string)
                    } else if (stream.match('/*')) {
                        //comments starting with /*
                        state.stack.unshift(stateType.comment)
                        state.commentType = commentType.slash
                    } else if (stream.match('(*')) {
                        //comments starting with (*
                        state.stack.unshift(stateType.comment)
                        state.commentType = commentType.parenthesis
                    }
                }

                //return state
                //stack has
                switch (state.stack[0]) {
                    case stateType._string:
                        while (state.stack[0] === stateType._string && !stream.eol()) {
                            if (stream.peek() === state.stringType) {
                                stream.next() // Skip quote
                                state.stack.shift() // Clear flag
                            } else if (stream.peek() === '\\') {
                                stream.next()
                                stream.next()
                            } else {
                                stream.match(/^.[^\\\"\']*/)
                            }
                        }
                        return state.lhs ? 'property string' : 'string' // Token style

                    case stateType.comment:
                        while (state.stack[0] === stateType.comment && !stream.eol()) {
                            if (state.commentType === commentType.slash && stream.match('*/')) {
                                state.stack.shift() // Clear flag
                                state.commentType = null
                            } else if (state.commentType === commentType.parenthesis && stream.match('*)')) {
                                state.stack.shift() // Clear flag
                                state.commentType = null
                            } else {
                                stream.match(/^.[^\*]*/)
                            }
                        }
                        return 'comment'

                    case stateType.characterClass:
                        while (state.stack[0] === stateType.characterClass && !stream.eol()) {
                            if (!(stream.match(/^[^\]\\]+/) || stream.match('.'))) {
                                state.stack.shift()
                            }
                        }
                        return 'operator'
                }

                var peek = stream.peek()

                if (bracesMode !== null && (state.braced || peek === '{')) {
                    if (state.localState === null) state.localState = CodeMirror.startState(bracesMode)

                    var token = bracesMode.token(stream, state.localState),
                        text = stream.current()

                    if (!token) {
                        for (var i = 0; i < text.length; i++) {
                            if (text[i] === '{') {
                                if (state.braced === 0) {
                                    token = 'matchingbracket'
                                }
                                state.braced++
                            } else if (text[i] === '}') {
                                state.braced--
                                if (state.braced === 0) {
                                    token = 'matchingbracket'
                                }
                            }
                        }
                    }
                    return token
                }

                //no stack
                switch (peek) {
                    case '[':
                        stream.next()
                        state.stack.unshift(stateType.characterClass)
                        return 'bracket'
                    case ':':
                    case '|':
                    case ';':
                        stream.next()
                        return 'operator'
                    case '%':
                        if (stream.match('%%')) {
                            return 'header'
                        } else if (stream.match(/[%][A-Za-z]+/)) {
                            return 'keyword'
                        } else if (stream.match(/[%][}]/)) {
                            return 'matchingbracket'
                        }
                        break
                    case '/':
                        if (stream.match(/[\/][A-Za-z]+/)) {
                            return 'keyword'
                        }
                    case '\\':
                        if (stream.match(/[\][a-z]+/)) {
                            return 'string-2'
                        }
                    case '.':
                        if (stream.match('.')) {
                            return 'atom'
                        }
                    case '*':
                    case '-':
                    case '+':
                    case '^':
                        if (stream.match(peek)) {
                            return 'atom'
                        }
                    case '$':
                        if (stream.match('$$')) {
                            return 'builtin'
                        } else if (stream.match(/[$][0-9]+/)) {
                            return 'variable-3'
                        }
                    case '<':
                        if (stream.match(/<<[a-zA-Z_]+>>/)) {
                            return 'builtin'
                        }
                }

                if (stream.match('//')) {
                    stream.skipToEnd()
                    return 'comment'
                } else if (stream.match('return')) {
                    return 'operator'
                } else if (stream.match(/^[a-zA-Z_][a-zA-Z0-9_]*/)) {
                    if (stream.match(/(?=[\(.])/)) {
                        return 'variable'
                    } else if (stream.match(/(?=[\s\n]*[:=])/)) {
                        return 'def'
                    }
                    return 'variable-2'
                } else if (['[', ']', '(', ')'].indexOf(stream.peek()) != -1) {
                    stream.next()
                    return 'bracket'
                } else if (!stream.eatSpace()) {
                    stream.next()
                }
                return null
            },
        }
    })

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