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

// Yacas mode copyright (c) 2015 by Grzegorz Mazur
// Loosely based on mathematica mode by Calin Barbat

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

        var bodiedOps = words(
            'Assert BackQuote D Defun Deriv For ForEach FromFile ' +
                'FromString Function Integrate InverseTaylor Limit ' +
                'LocalSymbols Macro MacroRule MacroRulePattern ' +
                'NIntegrate Rule RulePattern Subst TD TExplicitSum ' +
                'TSum Taylor Taylor1 Taylor2 Taylor3 ToFile ' +
                'ToStdout ToString TraceRule Until While'
        )

        // patterns
        var pFloatForm = '(?:(?:\\.\\d+|\\d+\\.\\d*|\\d+)(?:[eE][+-]?\\d+)?)'
        var pIdentifier = "(?:[a-zA-Z\\$'][a-zA-Z0-9\\$']*)"

        // regular expressions
        var reFloatForm = new RegExp(pFloatForm)
        var reIdentifier = new RegExp(pIdentifier)
        var rePattern = new RegExp(pIdentifier + '?_' + pIdentifier)
        var reFunctionLike = new RegExp(pIdentifier + '\\s*\\(')

        function tokenBase(stream, state) {
            var ch

            // get next character
            ch = stream.next()

            // string
            if (ch === '"') {
                state.tokenize = tokenString
                return state.tokenize(stream, state)
            }

            // comment
            if (ch === '/') {
                if (stream.eat('*')) {
                    state.tokenize = tokenComment
                    return state.tokenize(stream, state)
                }
                if (stream.eat('/')) {
                    stream.skipToEnd()
                    return 'comment'
                }
            }

            // go back one character
            stream.backUp(1)

            // update scope info
            var m = stream.match(/^(\w+)\s*\(/, false)
            if (m !== null && bodiedOps.hasOwnProperty(m[1])) state.scopes.push('bodied')

            var scope = currentScope(state)

            if (scope === 'bodied' && ch === '[') state.scopes.pop()

            if (ch === '[' || ch === '{' || ch === '(') state.scopes.push(ch)

            scope = currentScope(state)

            if ((scope === '[' && ch === ']') || (scope === '{' && ch === '}') || (scope === '(' && ch === ')')) state.scopes.pop()

            if (ch === ';') {
                while (scope === 'bodied') {
                    state.scopes.pop()
                    scope = currentScope(state)
                }
            }

            // look for ordered rules
            if (stream.match(/\d+ *#/, true, false)) {
                return 'qualifier'
            }

            // look for numbers
            if (stream.match(reFloatForm, true, false)) {
                return 'number'
            }

            // look for placeholders
            if (stream.match(rePattern, true, false)) {
                return 'variable-3'
            }

            // match all braces separately
            if (stream.match(/(?:\[|\]|{|}|\(|\))/, true, false)) {
                return 'bracket'
            }

            // literals looking like function calls
            if (stream.match(reFunctionLike, true, false)) {
                stream.backUp(1)
                return 'variable'
            }

            // all other identifiers
            if (stream.match(reIdentifier, true, false)) {
                return 'variable-2'
            }

            // operators; note that operators like @@ or /; are matched separately for each symbol.
            if (stream.match(/(?:\\|\+|\-|\*|\/|,|;|\.|:|@|~|=|>|<|&|\||_|`|'|\^|\?|!|%|#)/, true, false)) {
                return 'operator'
            }

            // everything else is an error
            return 'error'
        }

        function tokenString(stream, state) {
            var next,
                end = false,
                escaped = false
            while ((next = stream.next()) != null) {
                if (next === '"' && !escaped) {
                    end = true
                    break
                }
                escaped = !escaped && next === '\\'
            }
            if (end && !escaped) {
                state.tokenize = tokenBase
            }
            return 'string'
        }

        function tokenComment(stream, state) {
            var prev, next
            while ((next = stream.next()) != null) {
                if (prev === '*' && next === '/') {
                    state.tokenize = tokenBase
                    break
                }
                prev = next
            }
            return 'comment'
        }

        function currentScope(state) {
            var scope = null
            if (state.scopes.length > 0) scope = state.scopes[state.scopes.length - 1]
            return scope
        }

        return {
            startState: function () {
                return {
                    tokenize: tokenBase,
                    scopes: [],
                }
            },
            token: function (stream, state) {
                if (stream.eatSpace()) return null
                return state.tokenize(stream, state)
            },
            indent: function (state, textAfter) {
                if (state.tokenize !== tokenBase && state.tokenize !== null) return CodeMirror.Pass

                var delta = 0
                if (textAfter === ']' || textAfter === '];' || textAfter === '}' || textAfter === '};' || textAfter === ');') delta = -1

                return (state.scopes.length + delta) * _config.indentUnit
            },
            electricChars: '{}[]();',
            blockCommentStart: '/*',
            blockCommentEnd: '*/',
            lineComment: '//',
        }
    })

    CodeMirror.defineMIME('text/x-yacas', {
        name: 'yacas',
    })
})