// 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'

    function bracketFolding(pairs) {
        return function (cm, start) {
            var line = start.line,
                lineText = cm.getLine(line)

            function findOpening(pair) {
                var tokenType
                for (var at = start.ch, pass = 0; ; ) {
                    var found = at <= 0 ? -1 : lineText.lastIndexOf(pair[0], at - 1)
                    if (found == -1) {
                        if (pass == 1) break
                        pass = 1
                        at = lineText.length
                        continue
                    }
                    if (pass == 1 && found < start.ch) break
                    tokenType = cm.getTokenTypeAt(CodeMirror.Pos(line, found + 1))
                    if (!/^(comment|string)/.test(tokenType)) return { ch: found + 1, tokenType: tokenType, pair: pair }
                    at = found - 1
                }
            }

            function findRange(found) {
                var count = 1,
                    lastLine = cm.lastLine(),
                    end,
                    startCh = found.ch,
                    endCh
                outer: for (var i = line; i <= lastLine; ++i) {
                    var text = cm.getLine(i),
                        pos = i == line ? startCh : 0
                    for (;;) {
                        var nextOpen = text.indexOf(found.pair[0], pos),
                            nextClose = text.indexOf(found.pair[1], pos)
                        if (nextOpen < 0) nextOpen = text.length
                        if (nextClose < 0) nextClose = text.length
                        pos = Math.min(nextOpen, nextClose)
                        if (pos == text.length) break
                        if (cm.getTokenTypeAt(CodeMirror.Pos(i, pos + 1)) == found.tokenType) {
                            if (pos == nextOpen) ++count
                            else if (!--count) {
                                end = i
                                endCh = pos
                                break outer
                            }
                        }
                        ++pos
                    }
                }

                if (end == null || line == end) return null
                return { from: CodeMirror.Pos(line, startCh), to: CodeMirror.Pos(end, endCh) }
            }

            var found = []
            for (var i = 0; i < pairs.length; i++) {
                var open = findOpening(pairs[i])
                if (open) found.push(open)
            }
            found.sort(function (a, b) {
                return a.ch - b.ch
            })
            for (var i = 0; i < found.length; i++) {
                var range = findRange(found[i])
                if (range) return range
            }
            return null
        }
    }

    CodeMirror.registerHelper(
        'fold',
        'brace',
        bracketFolding([
            ['{', '}'],
            ['[', ']'],
        ])
    )

    CodeMirror.registerHelper(
        'fold',
        'brace-paren',
        bracketFolding([
            ['{', '}'],
            ['[', ']'],
            ['(', ')'],
        ])
    )

    CodeMirror.registerHelper('fold', 'import', function (cm, start) {
        function hasImport(line) {
            if (line < cm.firstLine() || line > cm.lastLine()) return null
            var start = cm.getTokenAt(CodeMirror.Pos(line, 1))
            if (!/\S/.test(start.string)) start = cm.getTokenAt(CodeMirror.Pos(line, start.end + 1))
            if (start.type != 'keyword' || start.string != 'import') return null
            // Now find closing semicolon, return its position
            for (var i = line, e = Math.min(cm.lastLine(), line + 10); i <= e; ++i) {
                var text = cm.getLine(i),
                    semi = text.indexOf(';')
                if (semi != -1) return { startCh: start.end, end: CodeMirror.Pos(i, semi) }
            }
        }

        var startLine = start.line,
            has = hasImport(startLine),
            prev
        if (!has || hasImport(startLine - 1) || ((prev = hasImport(startLine - 2)) && prev.end.line == startLine - 1)) return null
        for (var end = has.end; ; ) {
            var next = hasImport(end.line + 1)
            if (next == null) break
            end = next.end
        }
        return { from: cm.clipPos(CodeMirror.Pos(startLine, has.startCh + 1)), to: end }
    })

    CodeMirror.registerHelper('fold', 'include', function (cm, start) {
        function hasInclude(line) {
            if (line < cm.firstLine() || line > cm.lastLine()) return null
            var start = cm.getTokenAt(CodeMirror.Pos(line, 1))
            if (!/\S/.test(start.string)) start = cm.getTokenAt(CodeMirror.Pos(line, start.end + 1))
            if (start.type == 'meta' && start.string.slice(0, 8) == '#include') return start.start + 8
        }

        var startLine = start.line,
            has = hasInclude(startLine)
        if (has == null || hasInclude(startLine - 1) != null) return null
        for (var end = startLine; ; ) {
            var next = hasInclude(end + 1)
            if (next == null) break
            ++end
        }
        return { from: CodeMirror.Pos(startLine, has + 1), to: cm.clipPos(CodeMirror.Pos(end)) }
    })
})