// 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.defineExtension('annotateScrollbar', function (options) {
        if (typeof options == 'string') options = { className: options }
        return new Annotation(this, options)
    })

    CodeMirror.defineOption('scrollButtonHeight', 0)

    function Annotation(cm, options) {
        this.cm = cm
        this.options = options
        this.buttonHeight = options.scrollButtonHeight || cm.getOption('scrollButtonHeight')
        this.annotations = []
        this.doRedraw = this.doUpdate = null
        this.div = cm.getWrapperElement().appendChild(document.createElement('div'))
        this.div.style.cssText = 'position: absolute; right: 0; top: 0; z-index: 7; pointer-events: none'
        this.computeScale()

        function scheduleRedraw(delay) {
            clearTimeout(self.doRedraw)
            self.doRedraw = setTimeout(function () {
                self.redraw()
            }, delay)
        }

        var self = this
        cm.on(
            'refresh',
            (this.resizeHandler = function () {
                clearTimeout(self.doUpdate)
                self.doUpdate = setTimeout(function () {
                    if (self.computeScale()) scheduleRedraw(20)
                }, 100)
            })
        )
        cm.on('markerAdded', this.resizeHandler)
        cm.on('markerCleared', this.resizeHandler)
        if (options.listenForChanges !== false)
            cm.on(
                'changes',
                (this.changeHandler = function () {
                    scheduleRedraw(250)
                })
            )
    }

    Annotation.prototype.computeScale = function () {
        var cm = this.cm
        var hScale = (cm.getWrapperElement().clientHeight - cm.display.barHeight - this.buttonHeight * 2) / cm.getScrollerElement().scrollHeight
        if (hScale != this.hScale) {
            this.hScale = hScale
            return true
        }
    }

    Annotation.prototype.update = function (annotations) {
        this.annotations = annotations
        this.redraw()
    }

    Annotation.prototype.redraw = function (compute) {
        if (compute !== false) this.computeScale()
        var cm = this.cm,
            hScale = this.hScale

        var frag = document.createDocumentFragment(),
            anns = this.annotations

        var wrapping = cm.getOption('lineWrapping')
        var singleLineH = wrapping && cm.defaultTextHeight() * 1.5
        var curLine = null,
            curLineObj = null

        function getY(pos, top) {
            if (curLine != pos.line) {
                curLine = pos.line
                curLineObj = cm.getLineHandle(pos.line)
                var visual = cm.getLineHandleVisualStart(curLineObj)
                if (visual != curLineObj) {
                    curLine = cm.getLineNumber(visual)
                    curLineObj = visual
                }
            }
            if ((curLineObj.widgets && curLineObj.widgets.length) || (wrapping && curLineObj.height > singleLineH)) return cm.charCoords(pos, 'local')[top ? 'top' : 'bottom']
            var topY = cm.heightAtLine(curLineObj, 'local')
            return topY + (top ? 0 : curLineObj.height)
        }

        var lastLine = cm.lastLine()
        if (cm.display.barWidth)
            for (var i = 0, nextTop; i < anns.length; i++) {
                var ann = anns[i]
                if (ann.to.line > lastLine) continue
                var top = nextTop || getY(ann.from, true) * hScale
                var bottom = getY(ann.to, false) * hScale
                while (i < anns.length - 1) {
                    if (anns[i + 1].to.line > lastLine) break
                    nextTop = getY(anns[i + 1].from, true) * hScale
                    if (nextTop > bottom + 0.9) break
                    ann = anns[++i]
                    bottom = getY(ann.to, false) * hScale
                }
                if (bottom == top) continue
                var height = Math.max(bottom - top, 3)

                var elt = frag.appendChild(document.createElement('div'))
                elt.style.cssText = 'position: absolute; right: 0px; width: ' + Math.max(cm.display.barWidth - 1, 2) + 'px; top: ' + (top + this.buttonHeight) + 'px; height: ' + height + 'px'
                elt.className = this.options.className
                if (ann.id) {
                    elt.setAttribute('annotation-id', ann.id)
                }
            }
        this.div.textContent = ''
        this.div.appendChild(frag)
    }

    Annotation.prototype.clear = function () {
        this.cm.off('refresh', this.resizeHandler)
        this.cm.off('markerAdded', this.resizeHandler)
        this.cm.off('markerCleared', this.resizeHandler)
        if (this.changeHandler) this.cm.off('changes', this.changeHandler)
        this.div.parentNode.removeChild(this.div)
    }
})