// 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'
    var WRAP_CLASS = 'CodeMirror-activeline'
    var BACK_CLASS = 'CodeMirror-activeline-background'
    var GUTT_CLASS = 'CodeMirror-activeline-gutter'

    CodeMirror.defineOption('styleActiveLine', false, function (cm, val, old) {
        var prev = old == CodeMirror.Init ? false : old
        if (val == prev) return
        if (prev) {
            cm.off('beforeSelectionChange', selectionChange)
            clearActiveLines(cm)
            delete cm.state.activeLines
        }
        if (val) {
            cm.state.activeLines = []
            updateActiveLines(cm, cm.listSelections())
            cm.on('beforeSelectionChange', selectionChange)
        }
    })

    function clearActiveLines(cm) {
        for (var i = 0; i < cm.state.activeLines.length; i++) {
            cm.removeLineClass(cm.state.activeLines[i], 'wrap', WRAP_CLASS)
            cm.removeLineClass(cm.state.activeLines[i], 'background', BACK_CLASS)
            cm.removeLineClass(cm.state.activeLines[i], 'gutter', GUTT_CLASS)
        }
    }

    function sameArray(a, b) {
        if (a.length != b.length) return false
        for (var i = 0; i < a.length; i++) if (a[i] != b[i]) return false
        return true
    }

    function updateActiveLines(cm, ranges) {
        var active = []
        for (var i = 0; i < ranges.length; i++) {
            var range = ranges[i]
            var option = cm.getOption('styleActiveLine')
            if (typeof option == 'object' && option.nonEmpty ? range.anchor.line != range.head.line : !range.empty()) continue
            var line = cm.getLineHandleVisualStart(range.head.line)
            if (active[active.length - 1] != line) active.push(line)
        }
        if (sameArray(cm.state.activeLines, active)) return
        cm.operation(function () {
            clearActiveLines(cm)
            for (var i = 0; i < active.length; i++) {
                cm.addLineClass(active[i], 'wrap', WRAP_CLASS)
                cm.addLineClass(active[i], 'background', BACK_CLASS)
                cm.addLineClass(active[i], 'gutter', GUTT_CLASS)
            }
            cm.state.activeLines = active
        })
    }

    function selectionChange(cm, sel) {
        updateActiveLines(cm, sel.ranges)
    }
})