// CodeMirror, copyright (c) by Marijn Haverbeke and others
// Distributed under an MIT license: https://codemirror.net/LICENSE

// Highlighting text that matches the selection
//
// Defines an option highlightSelectionMatches, which, when enabled,
// will style strings that match the selection throughout the
// document.
//
// The option can be set to true to simply enable it, or to a
// {minChars, style, wordsOnly, showToken, delay} object to explicitly
// configure it. minChars is the minimum amount of characters that should be
// selected for the behavior to occur, and style is the token style to
// apply to the matches. This will be prefixed by "cm-" to create an
// actual CSS class name. If wordsOnly is enabled, the matches will be
// highlighted only if the selected text is a word. showToken, when enabled,
// will cause the current token to be highlighted when nothing is selected.
// delay is used to specify how much time to wait, in milliseconds, before
// highlighting the matches. If annotateScrollbar is enabled, the occurrences
// will be highlighted on the scrollbar via the matchesonscrollbar addon.

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

    var defaults = {
        style: 'matchhighlight',
        minChars: 2,
        delay: 100,
        wordsOnly: false,
        annotateScrollbar: false,
        showToken: false,
        trim: true,
    }

    function State(options) {
        this.options = {}
        for (var name in defaults) this.options[name] = (options && options.hasOwnProperty(name) ? options : defaults)[name]
        this.overlay = this.timeout = null
        this.matchesonscroll = null
        this.active = false
    }

    CodeMirror.defineOption('highlightSelectionMatches', false, function (cm, val, old) {
        if (old && old != CodeMirror.Init) {
            removeOverlay(cm)
            clearTimeout(cm.state.matchHighlighter.timeout)
            cm.state.matchHighlighter = null
            cm.off('cursorActivity', cursorActivity)
            cm.off('focus', onFocus)
        }
        if (val) {
            var state = (cm.state.matchHighlighter = new State(val))
            if (cm.hasFocus()) {
                state.active = true
                highlightMatches(cm)
            } else {
                cm.on('focus', onFocus)
            }
            cm.on('cursorActivity', cursorActivity)
        }
    })

    function cursorActivity(cm) {
        var state = cm.state.matchHighlighter
        if (state.active || cm.hasFocus()) scheduleHighlight(cm, state)
    }

    function onFocus(cm) {
        var state = cm.state.matchHighlighter
        if (!state.active) {
            state.active = true
            scheduleHighlight(cm, state)
        }
    }

    function scheduleHighlight(cm, state) {
        clearTimeout(state.timeout)
        state.timeout = setTimeout(function () {
            highlightMatches(cm)
        }, state.options.delay)
    }

    function addOverlay(cm, query, hasBoundary, style) {
        var state = cm.state.matchHighlighter
        cm.addOverlay((state.overlay = makeOverlay(query, hasBoundary, style)))
        if (state.options.annotateScrollbar && cm.showMatchesOnScrollbar) {
            var searchFor = hasBoundary
                ? new RegExp((/\w/.test(query.charAt(0)) ? '\\b' : '') + query.replace(/[\\\[.+*?(){|^$]/g, '\\$&') + (/\w/.test(query.charAt(query.length - 1)) ? '\\b' : ''))
                : query
            state.matchesonscroll = cm.showMatchesOnScrollbar(searchFor, false, { className: 'CodeMirror-selection-highlight-scrollbar' })
        }
    }

    function removeOverlay(cm) {
        var state = cm.state.matchHighlighter
        if (state.overlay) {
            cm.removeOverlay(state.overlay)
            state.overlay = null
            if (state.matchesonscroll) {
                state.matchesonscroll.clear()
                state.matchesonscroll = null
            }
        }
    }

    function highlightMatches(cm) {
        cm.operation(function () {
            var state = cm.state.matchHighlighter
            removeOverlay(cm)
            if (!cm.somethingSelected() && state.options.showToken) {
                var re = state.options.showToken === true ? /[\w$]/ : state.options.showToken
                var cur = cm.getCursor(),
                    line = cm.getLine(cur.line),
                    start = cur.ch,
                    end = start
                while (start && re.test(line.charAt(start - 1))) --start
                while (end < line.length && re.test(line.charAt(end))) ++end
                if (start < end) addOverlay(cm, line.slice(start, end), re, state.options.style)
                return
            }
            var from = cm.getCursor('from'),
                to = cm.getCursor('to')
            if (from.line != to.line) return
            if (state.options.wordsOnly && !isWord(cm, from, to)) return
            var selection = cm.getRange(from, to)
            if (state.options.trim) selection = selection.replace(/^\s+|\s+$/g, '')
            if (selection.length >= state.options.minChars) addOverlay(cm, selection, false, state.options.style)
        })
    }

    function isWord(cm, from, to) {
        var str = cm.getRange(from, to)
        if (str.match(/^\w+$/) !== null) {
            if (from.ch > 0) {
                var pos = { line: from.line, ch: from.ch - 1 }
                var chr = cm.getRange(pos, from)
                if (chr.match(/\W/) === null) return false
            }
            if (to.ch < cm.getLine(from.line).length) {
                var pos = { line: to.line, ch: to.ch + 1 }
                var chr = cm.getRange(to, pos)
                if (chr.match(/\W/) === null) return false
            }
            return true
        } else return false
    }

    function boundariesAround(stream, re) {
        return (!stream.start || !re.test(stream.string.charAt(stream.start - 1))) && (stream.pos == stream.string.length || !re.test(stream.string.charAt(stream.pos)))
    }

    function makeOverlay(query, hasBoundary, style) {
        return {
            token: function (stream) {
                if (stream.match(query) && (!hasBoundary || boundariesAround(stream, hasBoundary))) return style
                stream.next()
                stream.skipTo(query.charAt(0)) || stream.skipToEnd()
            },
        }
    }
})