// 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.registerGlobalHelper(
        'fold',
        'comment',
        function (mode) {
            return mode.blockCommentStart && mode.blockCommentEnd
        },
        function (cm, start) {
            var mode = cm.getModeAt(start),
                startToken = mode.blockCommentStart,
                endToken = mode.blockCommentEnd
            if (!startToken || !endToken) return
            var line = start.line,
                lineText = cm.getLine(line)

            var startCh
            for (var at = start.ch, pass = 0; ; ) {
                var found = at <= 0 ? -1 : lineText.lastIndexOf(startToken, at - 1)
                if (found == -1) {
                    if (pass == 1) return
                    pass = 1
                    at = lineText.length
                    continue
                }
                if (pass == 1 && found < start.ch) return
                if (
                    /comment/.test(cm.getTokenTypeAt(CodeMirror.Pos(line, found + 1))) &&
                    (found == 0 || lineText.slice(found - endToken.length, found) == endToken || !/comment/.test(cm.getTokenTypeAt(CodeMirror.Pos(line, found))))
                ) {
                    startCh = found + startToken.length
                    break
                }
                at = found - 1
            }

            var depth = 1,
                lastLine = cm.lastLine(),
                end,
                endCh
            outer: for (var i = line; i <= lastLine; ++i) {
                var text = cm.getLine(i),
                    pos = i == line ? startCh : 0
                for (;;) {
                    var nextOpen = text.indexOf(startToken, pos),
                        nextClose = text.indexOf(endToken, pos)
                    if (nextOpen < 0) nextOpen = text.length
                    if (nextClose < 0) nextClose = text.length
                    pos = Math.min(nextOpen, nextClose)
                    if (pos == text.length) break
                    if (pos == nextOpen) ++depth
                    else if (!--depth) {
                        end = i
                        endCh = pos
                        break outer
                    }
                    ++pos
                }
            }
            if (end == null || (line == end && endCh == startCh)) return
            return { from: CodeMirror.Pos(line, startCh), to: CodeMirror.Pos(end, endCh) }
        }
    )
})