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

/**
 * Author: Koh Zi Han, based on implementation by Koh Zi Chun
 * Improved by: Jakub T. Jankiewicz
 */

;(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('scheme', function () {
        var BUILTIN = 'builtin',
            COMMENT = 'comment',
            STRING = 'string',
            SYMBOL = 'symbol',
            ATOM = 'atom',
            NUMBER = 'number',
            BRACKET = 'bracket'
        var INDENT_WORD_SKIP = 2

        function makeKeywords(str) {
            var obj = {},
                words = str.split(' ')
            for (var i = 0; i < words.length; ++i) obj[words[i]] = true
            return obj
        }

        var keywords = makeKeywords(
            'λ case-lambda call/cc class cond-expand define-class define-values exit-handler field import inherit init-field interface let*-values let-values let/ec mixin opt-lambda override protect provide public rename require require-for-syntax syntax syntax-case syntax-error unit/sig unless when with-syntax and begin call-with-current-continuation call-with-input-file call-with-output-file case cond define define-syntax define-macro defmacro delay do dynamic-wind else for-each if lambda let let* let-syntax letrec letrec-syntax map or syntax-rules abs acos angle append apply asin assoc assq assv atan boolean? caar cadr call-with-input-file call-with-output-file call-with-values car cdddar cddddr cdr ceiling char->integer char-alphabetic? char-ci<=? char-ci<? char-ci=? char-ci>=? char-ci>? char-downcase char-lower-case? char-numeric? char-ready? char-upcase char-upper-case? char-whitespace? char<=? char<? char=? char>=? char>? char? close-input-port close-output-port complex? cons cos current-input-port current-output-port denominator display eof-object? eq? equal? eqv? eval even? exact->inexact exact? exp expt #f floor force gcd imag-part inexact->exact inexact? input-port? integer->char integer? interaction-environment lcm length list list->string list->vector list-ref list-tail list? load log magnitude make-polar make-rectangular make-string make-vector max member memq memv min modulo negative? newline not null-environment null? number->string number? numerator odd? open-input-file open-output-file output-port? pair? peek-char port? positive? procedure? quasiquote quote quotient rational? rationalize read read-char real-part real? remainder reverse round scheme-report-environment set! set-car! set-cdr! sin sqrt string string->list string->number string->symbol string-append string-ci<=? string-ci<? string-ci=? string-ci>=? string-ci>? string-copy string-fill! string-length string-ref string-set! string<=? string<? string=? string>=? string>? string? substring symbol->string symbol? #t tan transcript-off transcript-on truncate values vector vector->list vector-fill! vector-length vector-ref vector-set! with-input-from-file with-output-to-file write write-char zero?'
        )
        var indentKeys = makeKeywords('define let letrec let* lambda define-macro defmacro let-syntax letrec-syntax let-values let*-values define-syntax syntax-rules define-values when unless')

        function stateStack(indent, type, prev) {
            // represents a state stack object
            this.indent = indent
            this.type = type
            this.prev = prev
        }

        function pushStack(state, indent, type) {
            state.indentStack = new stateStack(indent, type, state.indentStack)
        }

        function popStack(state) {
            state.indentStack = state.indentStack.prev
        }

        var binaryMatcher = new RegExp(
            /^(?:[-+]i|[-+][01]+#*(?:\/[01]+#*)?i|[-+]?[01]+#*(?:\/[01]+#*)?@[-+]?[01]+#*(?:\/[01]+#*)?|[-+]?[01]+#*(?:\/[01]+#*)?[-+](?:[01]+#*(?:\/[01]+#*)?)?i|[-+]?[01]+#*(?:\/[01]+#*)?)(?=[()\s;"]|$)/i
        )
        var octalMatcher = new RegExp(
            /^(?:[-+]i|[-+][0-7]+#*(?:\/[0-7]+#*)?i|[-+]?[0-7]+#*(?:\/[0-7]+#*)?@[-+]?[0-7]+#*(?:\/[0-7]+#*)?|[-+]?[0-7]+#*(?:\/[0-7]+#*)?[-+](?:[0-7]+#*(?:\/[0-7]+#*)?)?i|[-+]?[0-7]+#*(?:\/[0-7]+#*)?)(?=[()\s;"]|$)/i
        )
        var hexMatcher = new RegExp(
            /^(?:[-+]i|[-+][\da-f]+#*(?:\/[\da-f]+#*)?i|[-+]?[\da-f]+#*(?:\/[\da-f]+#*)?@[-+]?[\da-f]+#*(?:\/[\da-f]+#*)?|[-+]?[\da-f]+#*(?:\/[\da-f]+#*)?[-+](?:[\da-f]+#*(?:\/[\da-f]+#*)?)?i|[-+]?[\da-f]+#*(?:\/[\da-f]+#*)?)(?=[()\s;"]|$)/i
        )
        var decimalMatcher = new RegExp(
            /^(?:[-+]i|[-+](?:(?:(?:\d+#+\.?#*|\d+\.\d*#*|\.\d+#*|\d+)(?:[esfdl][-+]?\d+)?)|\d+#*\/\d+#*)i|[-+]?(?:(?:(?:\d+#+\.?#*|\d+\.\d*#*|\.\d+#*|\d+)(?:[esfdl][-+]?\d+)?)|\d+#*\/\d+#*)@[-+]?(?:(?:(?:\d+#+\.?#*|\d+\.\d*#*|\.\d+#*|\d+)(?:[esfdl][-+]?\d+)?)|\d+#*\/\d+#*)|[-+]?(?:(?:(?:\d+#+\.?#*|\d+\.\d*#*|\.\d+#*|\d+)(?:[esfdl][-+]?\d+)?)|\d+#*\/\d+#*)[-+](?:(?:(?:\d+#+\.?#*|\d+\.\d*#*|\.\d+#*|\d+)(?:[esfdl][-+]?\d+)?)|\d+#*\/\d+#*)?i|(?:(?:(?:\d+#+\.?#*|\d+\.\d*#*|\.\d+#*|\d+)(?:[esfdl][-+]?\d+)?)|\d+#*\/\d+#*))(?=[()\s;"]|$)/i
        )

        function isBinaryNumber(stream) {
            return stream.match(binaryMatcher)
        }

        function isOctalNumber(stream) {
            return stream.match(octalMatcher)
        }

        function isDecimalNumber(stream, backup) {
            if (backup === true) {
                stream.backUp(1)
            }
            return stream.match(decimalMatcher)
        }

        function isHexNumber(stream) {
            return stream.match(hexMatcher)
        }

        function processEscapedSequence(stream, options) {
            var next,
                escaped = false
            while ((next = stream.next()) != null) {
                if (next == options.token && !escaped) {
                    options.state.mode = false
                    break
                }
                escaped = !escaped && next == '\\'
            }
        }

        return {
            startState: function () {
                return {
                    indentStack: null,
                    indentation: 0,
                    mode: false,
                    sExprComment: false,
                    sExprQuote: false,
                }
            },

            token: function (stream, state) {
                if (state.indentStack == null && stream.sol()) {
                    // update indentation, but only if indentStack is empty
                    state.indentation = stream.indentation()
                }

                // skip spaces
                if (stream.eatSpace()) {
                    return null
                }
                var returnType = null

                switch (state.mode) {
                    case 'string': // multi-line string parsing mode
                        processEscapedSequence(stream, {
                            token: '"',
                            state: state,
                        })
                        returnType = STRING // continue on in scheme-string mode
                        break
                    case 'symbol': // escape symbol
                        processEscapedSequence(stream, {
                            token: '|',
                            state: state,
                        })
                        returnType = SYMBOL // continue on in scheme-symbol mode
                        break
                    case 'comment': // comment parsing mode
                        var next,
                            maybeEnd = false
                        while ((next = stream.next()) != null) {
                            if (next == '#' && maybeEnd) {
                                state.mode = false
                                break
                            }
                            maybeEnd = next == '|'
                        }
                        returnType = COMMENT
                        break
                    case 's-expr-comment': // s-expr commenting mode
                        state.mode = false
                        if (stream.peek() == '(' || stream.peek() == '[') {
                            // actually start scheme s-expr commenting mode
                            state.sExprComment = 0
                        } else {
                            // if not we just comment the entire of the next token
                            stream.eatWhile(/[^\s\(\)\[\]]/) // eat symbol atom
                            returnType = COMMENT
                            break
                        }
                    default:
                        // default parsing mode
                        var ch = stream.next()

                        if (ch == '"') {
                            state.mode = 'string'
                            returnType = STRING
                        } else if (ch == "'") {
                            if (stream.peek() == '(' || stream.peek() == '[') {
                                if (typeof state.sExprQuote != 'number') {
                                    state.sExprQuote = 0
                                } // else already in a quoted expression
                                returnType = ATOM
                            } else {
                                stream.eatWhile(/[\w_\-!$%&*+\.\/:<=>?@\^~]/)
                                returnType = ATOM
                            }
                        } else if (ch == '|') {
                            state.mode = 'symbol'
                            returnType = SYMBOL
                        } else if (ch == '#') {
                            if (stream.eat('|')) {
                                // Multi-line comment
                                state.mode = 'comment' // toggle to comment mode
                                returnType = COMMENT
                            } else if (stream.eat(/[tf]/i)) {
                                // #t/#f (atom)
                                returnType = ATOM
                            } else if (stream.eat(';')) {
                                // S-Expr comment
                                state.mode = 's-expr-comment'
                                returnType = COMMENT
                            } else {
                                var numTest = null,
                                    hasExactness = false,
                                    hasRadix = true
                                if (stream.eat(/[ei]/i)) {
                                    hasExactness = true
                                } else {
                                    stream.backUp(1) // must be radix specifier
                                }
                                if (stream.match(/^#b/i)) {
                                    numTest = isBinaryNumber
                                } else if (stream.match(/^#o/i)) {
                                    numTest = isOctalNumber
                                } else if (stream.match(/^#x/i)) {
                                    numTest = isHexNumber
                                } else if (stream.match(/^#d/i)) {
                                    numTest = isDecimalNumber
                                } else if (stream.match(/^[-+0-9.]/, false)) {
                                    hasRadix = false
                                    numTest = isDecimalNumber
                                    // re-consume the initial # if all matches failed
                                } else if (!hasExactness) {
                                    stream.eat('#')
                                }
                                if (numTest != null) {
                                    if (hasRadix && !hasExactness) {
                                        // consume optional exactness after radix
                                        stream.match(/^#[ei]/i)
                                    }
                                    if (numTest(stream)) returnType = NUMBER
                                }
                            }
                        } else if (/^[-+0-9.]/.test(ch) && isDecimalNumber(stream, true)) {
                            // match non-prefixed number, must be decimal
                            returnType = NUMBER
                        } else if (ch == ';') {
                            // comment
                            stream.skipToEnd() // rest of the line is a comment
                            returnType = COMMENT
                        } else if (ch == '(' || ch == '[') {
                            var keyWord = ''
                            var indentTemp = stream.column(),
                                letter
                            /**
                        Either
                        (indent-word ..
                        (non-indent-word ..
                        (;something else, bracket, etc.
                        */

                            while ((letter = stream.eat(/[^\s\(\[\;\)\]]/)) != null) {
                                keyWord += letter
                            }

                            if (keyWord.length > 0 && indentKeys.propertyIsEnumerable(keyWord)) {
                                // indent-word

                                pushStack(state, indentTemp + INDENT_WORD_SKIP, ch)
                            } else {
                                // non-indent word
                                // we continue eating the spaces
                                stream.eatSpace()
                                if (stream.eol() || stream.peek() == ';') {
                                    // nothing significant after
                                    // we restart indentation 1 space after
                                    pushStack(state, indentTemp + 1, ch)
                                } else {
                                    pushStack(state, indentTemp + stream.current().length, ch) // else we match
                                }
                            }
                            stream.backUp(stream.current().length - 1) // undo all the eating

                            if (typeof state.sExprComment == 'number') state.sExprComment++
                            if (typeof state.sExprQuote == 'number') state.sExprQuote++

                            returnType = BRACKET
                        } else if (ch == ')' || ch == ']') {
                            returnType = BRACKET
                            if (state.indentStack != null && state.indentStack.type == (ch == ')' ? '(' : '[')) {
                                popStack(state)

                                if (typeof state.sExprComment == 'number') {
                                    if (--state.sExprComment == 0) {
                                        returnType = COMMENT // final closing bracket
                                        state.sExprComment = false // turn off s-expr commenting mode
                                    }
                                }
                                if (typeof state.sExprQuote == 'number') {
                                    if (--state.sExprQuote == 0) {
                                        returnType = ATOM // final closing bracket
                                        state.sExprQuote = false // turn off s-expr quote mode
                                    }
                                }
                            }
                        } else {
                            stream.eatWhile(/[\w_\-!$%&*+\.\/:<=>?@\^~]/)

                            if (keywords && keywords.propertyIsEnumerable(stream.current())) {
                                returnType = BUILTIN
                            } else returnType = 'variable'
                        }
                }
                return typeof state.sExprComment == 'number' ? COMMENT : typeof state.sExprQuote == 'number' ? ATOM : returnType
            },

            indent: function (state) {
                if (state.indentStack == null) return state.indentation
                return state.indentStack.indent
            },

            fold: 'brace-paren',
            closeBrackets: { pairs: '()[]{}""' },
            lineComment: ';;',
        }
    })

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