// 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'), require('./foldcode'))
    else if (typeof define == 'function' && define.amd)
        // AMD
        define(['../../lib/codemirror', './foldcode'], mod)
    // Plain browser env
    else mod(CodeMirror)
})(function (CodeMirror) {
    'use strict'

    CodeMirror.defineOption('foldGutter', false, function (cm, val, old) {
        if (old && old != CodeMirror.Init) {
            cm.clearGutter(cm.state.foldGutter.options.gutter)
            cm.state.foldGutter = null
            cm.off('gutterClick', onGutterClick)
            cm.off('changes', onChange)
            cm.off('viewportChange', onViewportChange)
            cm.off('fold', onFold)
            cm.off('unfold', onFold)
            cm.off('swapDoc', onChange)
        }
        if (val) {
            cm.state.foldGutter = new State(parseOptions(val))
            updateInViewport(cm)
            cm.on('gutterClick', onGutterClick)
            cm.on('changes', onChange)
            cm.on('viewportChange', onViewportChange)
            cm.on('fold', onFold)
            cm.on('unfold', onFold)
            cm.on('swapDoc', onChange)
        }
    })

    var Pos = CodeMirror.Pos

    function State(options) {
        this.options = options
        this.from = this.to = 0
    }

    function parseOptions(opts) {
        if (opts === true) opts = {}
        if (opts.gutter == null) opts.gutter = 'CodeMirror-foldgutter'
        if (opts.indicatorOpen == null) opts.indicatorOpen = 'CodeMirror-foldgutter-open'
        if (opts.indicatorFolded == null) opts.indicatorFolded = 'CodeMirror-foldgutter-folded'
        return opts
    }

    function isFolded(cm, line) {
        var marks = cm.findMarks(Pos(line, 0), Pos(line + 1, 0))
        for (var i = 0; i < marks.length; ++i) {
            if (marks[i].__isFold) {
                var fromPos = marks[i].find(-1)
                if (fromPos && fromPos.line === line) return marks[i]
            }
        }
    }

    function marker(spec) {
        if (typeof spec == 'string') {
            var elt = document.createElement('div')
            elt.className = spec + ' CodeMirror-guttermarker-subtle'
            return elt
        } else {
            return spec.cloneNode(true)
        }
    }

    function updateFoldInfo(cm, from, to) {
        var opts = cm.state.foldGutter.options,
            cur = from - 1
        var minSize = cm.foldOption(opts, 'minFoldSize')
        var func = cm.foldOption(opts, 'rangeFinder')
        // we can reuse the built-in indicator element if its className matches the new state
        var clsFolded = typeof opts.indicatorFolded == 'string' && classTest(opts.indicatorFolded)
        var clsOpen = typeof opts.indicatorOpen == 'string' && classTest(opts.indicatorOpen)
        cm.eachLine(from, to, function (line) {
            ++cur
            var mark = null
            var old = line.gutterMarkers
            if (old) old = old[opts.gutter]
            if (isFolded(cm, cur)) {
                if (clsFolded && old && clsFolded.test(old.className)) return
                mark = marker(opts.indicatorFolded)
            } else {
                var pos = Pos(cur, 0)
                var range = func && func(cm, pos)
                if (range && range.to.line - range.from.line >= minSize) {
                    if (clsOpen && old && clsOpen.test(old.className)) return
                    mark = marker(opts.indicatorOpen)
                }
            }
            if (!mark && !old) return
            cm.setGutterMarker(line, opts.gutter, mark)
        })
    }

    // copied from CodeMirror/src/util/dom.js
    function classTest(cls) {
        return new RegExp('(^|\\s)' + cls + '(?:$|\\s)\\s*')
    }

    function updateInViewport(cm) {
        var vp = cm.getViewport(),
            state = cm.state.foldGutter
        if (!state) return
        cm.operation(function () {
            updateFoldInfo(cm, vp.from, vp.to)
        })
        state.from = vp.from
        state.to = vp.to
    }

    function onGutterClick(cm, line, gutter) {
        var state = cm.state.foldGutter
        if (!state) return
        var opts = state.options
        if (gutter != opts.gutter) return
        var folded = isFolded(cm, line)
        if (folded) folded.clear()
        else cm.foldCode(Pos(line, 0), opts)
    }

    function onChange(cm) {
        var state = cm.state.foldGutter
        if (!state) return
        var opts = state.options
        state.from = state.to = 0
        clearTimeout(state.changeUpdate)
        state.changeUpdate = setTimeout(function () {
            updateInViewport(cm)
        }, opts.foldOnChangeTimeSpan || 600)
    }

    function onViewportChange(cm) {
        var state = cm.state.foldGutter
        if (!state) return
        var opts = state.options
        clearTimeout(state.changeUpdate)
        state.changeUpdate = setTimeout(function () {
            var vp = cm.getViewport()
            if (state.from == state.to || vp.from - state.to > 20 || state.from - vp.to > 20) {
                updateInViewport(cm)
            } else {
                cm.operation(function () {
                    if (vp.from < state.from) {
                        updateFoldInfo(cm, vp.from, state.from)
                        state.from = vp.from
                    }
                    if (vp.to > state.to) {
                        updateFoldInfo(cm, state.to, vp.to)
                        state.to = vp.to
                    }
                })
            }
        }, opts.updateViewportTimeSpan || 400)
    }

    function onFold(cm, from) {
        var state = cm.state.foldGutter
        if (!state) return
        var line = from.line
        if (line >= state.from && line < state.to) updateFoldInfo(cm, line, line + 1)
    }
})