/**
 * Flattens an object recursively. Nested keys are joined with slashes ('/')
 * @param {object} obj The object to flatten
 * @returns {object} The flattened object
 */
export function flattenObj(obj) {
    const res = {}
    Object.entries(obj).forEach(([key, value]) => {
        if (typeof value === "object") {
            value = flattenObj(value)
            Object.entries(value).forEach(([key2, value2]) => {
                res[key + "/" + key2] = value2
            })
        } else {
            res[key] = value
        }
    })
    return res
}

// Code (Flag): https://en.wikipedia.org/wiki/Regional_indicator_symbol
// Tag: https://en.wikipedia.org/wiki/List_of_ISO_639-2_codes
export const LANGUAGES = {
    "fre-ca": {
        display: "Français CA",
        code: "ca",
        aliases: ["fr-ca", "vfq", "quebec", "québec", "ca", "canada"]
    },
    "fre": {
        display: "Français FR",
        code: "fr",
        aliases: ["fr", "fra", "french", "francais", "français", "vf", "vff", "france"]
    },
    "eng": {
        display: "English",
        code: "gb",
        aliases: ["en", "ang", "english", "anglais", "uk", "gb", "usa", "british", "american", "amérique", "amerique", "angleterre", "royaume-uni"]
    },
    "deu": {
        display: "Deutsch",
        code: "de",
        aliases: ["de", "ger", "german", "allemand", "deutsch", "germany", "allemagne"]
    },
    "ita": {
        display: "Italiano",
        code: "it",
        aliases: ["it", "ita", "italian", "italien", "italiano", "italy", "italie"]
    },
    "kor": {
        display: "Korean",
        code: "kr",
        aliases: ["ko", "kr", "cor", "korean", "coreen", "coréen", "corée", "coree", "korea"]
    },
    "jpn": {
        display: "Japanese",
        code: "jp",
        aliases: ["ja", "jp", "jap", "japanese", "japonais", "japon", "japan"]
    },
    "tur": {
        display: "Turkish",
        code: "tr",
        aliases: ["tu", "tr", "tür", "turkish", "turc", "turquie"]
    },
    "und": {
        display: "Undefined",
        code: "",
        aliases: []
    }
}

export function getLanguageAliases(langTag) {
    return [langTag].concat(LANGUAGES[langTag].aliases)
}

/**
 * Tries to find a language name in the given string
 * @param {string} value The string in which to search for a language
 * @returns {?string} The language key if it could be determined, null otherwise
 */
export function findLanguage(value) {
    for (const lang in LANGUAGES) {
        const aliases = getLanguageAliases(lang)
        const matches = aliases.some(a => {
            return new RegExp("\\b" + a + "\\b").test(value)
        })
        if (matches) {
            return lang
        }
    }
    return null
}

export function isLanguageTagAlias(langTag, value) {
    return getLanguageAliases(langTag).includes(value)
}

export function updateObjectFromJoinedKey(obj, joinedKey, value) {
    const keyParts = joinedKey.split("/")
    for (const part of keyParts.slice(0, -1)) {
        obj = obj[part]
    }
    obj[keyParts[keyParts.length - 1]] = value
}

/**
 * @param {string} code
 */
export function makeFlag(code) {
    return code.split("")
               .map(c => String.fromCodePoint(
                    0x1f1e6 + c.codePointAt(0) - 97
                ))
               .join("")
}

export function getLanguageOptions() {
    return Object.entries(LANGUAGES).map(([tag, props]) => {
        const flag = makeFlag(props.code)
        return {value: tag, display: `${flag} ${props.display}`}
    })
}