/**
 * Determines the current season based on a date (current date by default). Options include hemisphere (northern by default) and type (astronomical by default).
 *
 * @example
 * Basic usage
 * ```js
 * // Get the current season in the northern hemisphere using astronomical seasons
 * const season = getSeason();
 * console.log(season); // e.g., "spring"
 * ```
 *
 * @example
 * With options
 * ```js
 * // Get the season for a specific date in the southern hemisphere using meteorological seasons
 * const season = getSeason({ date: new Date('2023-06-15'), hemisphere: 'southern', type: 'meteorological' });
 * console.log(season); // e.g., "winter"
 * ```
 *
 * @param options - The options for determining the season.
 * @param options.date - The date to determine the season for.
 * @param options.hemisphere - The hemisphere ("northern" or "southern").
 * @param options.type - The type of season calculation ("meteorological" or "astronomical").
 *
 * @category Weather and climate
 */
export default function getSeason(
    options: {
        date?: Date
        hemisphere?: "northern" | "southern"
        type?: "meteorological" | "astronomical"
    } = {}
): "winter" | "spring" | "summer" | "fall" {
    const {
        date = new Date(),
        hemisphere = "northern",
        type = "astronomical",
    } = options

    const month = date.getMonth()

    let season: "winter" | "spring" | "summer" | "fall" | undefined

    if (type === "meteorological") {
        if (month >= 2 && month <= 4) {
            // March, April, and May
            season = "spring"
        } else if (month >= 5 && month <= 7) {
            // June, July, and August
            season = "summer"
        } else if (month >= 8 && month <= 10) {
            // September, October, and November
            season = "fall"
        } else {
            // December, January, and February
            season = "winter"
        }
    } else {
        // astronomical
        const day = date.getDate()
        if (month === 0 || month === 1) {
            // January and February
            season = "winter"
        } else if (month === 2) {
            // March
            if (day <= 20) {
                season = "winter"
            } else {
                season = "spring"
            }
        } else if (month === 3 || month === 4) {
            // April and May
            season = "spring"
        } else if (month === 5) {
            // June
            if (day <= 20) {
                season = "spring"
            } else {
                season = "summer"
            }
        } else if (month === 6 || month === 7) {
            // July and August
            season = "summer"
        } else if (month === 8) {
            // September
            if (day <= 20) {
                season = "summer"
            } else {
                season = "fall"
            }
        } else if (month === 9 || month === 10) {
            season = "fall"
        } else if (month === 11) {
            if (day <= 20) {
                season = "fall"
            } else {
                season = "winter"
            }
        }
    }

    if (typeof season !== "string") {
        throw new Error("No season")
    }

    if (hemisphere === "southern") {
        const oppositeSeasons: {
            [key: string]: "winter" | "spring" | "summer" | "fall"
        } = {
            winter: "summer",
            spring: "fall",
            summer: "winter",
            fall: "spring",
        }
        season = oppositeSeasons[season]
    }

    return season
}