function hsluv(hue, saturation, lightness, alpha=1.0) {
    let rgb = py.callSync("hsluv", [hue, saturation, lightness])
    return Qt.rgba(rgb[0], rgb[1], rgb[2], alpha)
}


function hsl(hue, saturation, lightness) {
    return hsla(hue, saturation, lightness)
}


function hsla(hue, saturation, lightness, alpha=1.0) {
    // Convert standard hsla(0-360, 1-100, 1-100, 0-1) to Qt format
    return Qt.hsla(hue / 360, saturation / 100, lightness / 100, alpha)
}


function hueFrom(string) {
    // Calculate and return a unique hue between 0 and 360 for the string
    let hue = 0
    for (let i = 0; i < string.length; i++) {
        hue += string.charCodeAt(i) * 99
    }
    return hue % 360
}


function nameColor(name) {
    return hsl(
        hueFrom(name),
        theme.controls.displayName.saturation,
        theme.controls.displayName.lightness,
    )
}


function coloredNameHtml(name, userId, displayText=null, disambiguate=false) {
    // substring: remove leading @
    return "<font color='" + nameColor(name || userId.substring(1)) + "'>" +
           escapeHtml(displayText || name || userId) +
           "</font>"
}


function escapeHtml(string) {
    // Replace special HTML characters by encoded alternatives
    return string.replace("&", "&amp;")
                 .replace("<", "&lt;")
                 .replace(">", "&gt;")
                 .replace('"', "&quot;")
                 .replace("'", "&#039;")
}


function processedEventText(ev) {
    if (ev.event_type == "RoomMessageEmote") {
        return "<i>" +
               coloredNameHtml(ev.sender_name, ev.sender_id) + " " +
               ev.content + "</i>"
    }

    if (ev.event_type.startsWith("RoomMessage")) { return ev.content }

    let text = qsTr(ev.content).arg(
        coloredNameHtml(ev.sender_name, ev.sender_id)
    )

    if (text.includes("%2") && ev.target_id) {
        text = text.arg(coloredNameHtml(ev.target_name, ev.target_id))
    }

    return text
}


function filterMatches(filter, text) {
    let filter_lower = filter.toLowerCase()

    if (filter_lower == filter) {
        // Consider case only if filter isn't all lowercase (smart case)
        filter = filter_lower
        text   = text.toLowerCase()
    }

    for (let word of filter.split(" ")) {
        if (word && ! text.includes(word)) {
            return false
        }
    }
    return true
}


function filterModelSource(source, filter_text, property="filter_string") {
    if (! filter_text) return source
    let results = []

    for (let i = 0;  i < source.length; i++) {
        if (filterMatches(filter_text, source[i][property])) {
            results.push(item)
        }
    }
    return results
}


function thumbnailParametersFor(width, height) {
    // https://matrix.org/docs/spec/client_server/latest#thumbnails

    if (width > 640 || height > 480)
        return {width: 800, height: 600, fillMode: Image.PreserveAspectFit}

    if (width > 320 || height > 240)
        return {width: 640, height: 480, fillMode: Image.PreserveAspectFit}

    if (width >  96 || height >  96)
        return {width: 320, height: 240, fillMode: Image.PreserveAspectFit}

    if (width >  32 || height >  32)
        return {width: 96, height: 96, fillMode: Image.PreserveAspectCrop}

    return {width: 32, height: 32, fillMode: Image.PreserveAspectCrop}
}


function minutesBetween(date1, date2) {
    return Math.round((((date2 - date1) % 86400000) % 3600000) / 60000)
}


function dateIsDay(date, dayDate) {
    return date.getDate() == dayDate.getDate() &&
           date.getMonth() == dayDate.getMonth() &&
           date.getFullYear() == dayDate.getFullYear()
}


function dateIsToday(date) {
    return dateIsDay(date, new Date())
}


function dateIsYesterday(date) {
    const yesterday = new Date()
    yesterday.setDate(yesterday.getDate() - 1)
    return dateIsDay(date, yesterday)
}


function formatTime(time, seconds=true) {
    return Qt.formatTime(
        time,

        Qt.locale().timeFormat(
            seconds ? Locale.LongFormat : Locale.NarrowFormat
        ).replace(/\./g, ":").replace(/ t$/, "")
        // en_DK.UTF-8 locale wrongfully gives "." separators;
        // remove the timezone at the end
    )
}


function getItem(array, mainKey, value) {
    for (let i = 0; i < array.length; i++) {
        if (array[i][mainKey] === value) { return array[i] }
    }
    return undefined
}