/**
 * 将数字转换为带单位的字符串
 * @example
 * readableNumberUnit(123456.789) // 12.35万
 */
export function readableNumberUnit(
    num: number,
    unit: "万" | "千万" | "亿" | "auto" = "auto",
    options?: {
        precision?: number
    }
): string {
    if (num === 0) return "0"

    const units = ["", "万", "亿"]
    let absNum = Math.abs(num)
    let precision = options?.precision || 2
    let result
    let chosenUnit = ""

    if (unit === "auto") {
        if (absNum >= 1e8) {
            chosenUnit = "亿"
            result = (num / 1e8).toString()
        } else if (absNum >= 1e4) {
            chosenUnit = "万"
            result = (num / 1e4).toString()
        } else {
            result = num.toString()
        }
    } else {
        chosenUnit = unit
        switch (unit) {
            case "亿":
                result = (num / 1e8).toString()
                break
            case "千万":
                result = (num / 1e7).toString()
                break
            case "万":
                result = (num / 1e4).toString()
                break
            default:
                result = num.toString()
        }
    }

    // 去掉小数点后不必要的 0 并确保整数部分不进位

    if (result.includes(".")) {
        let [int, decimal] = result.split(".")
        decimal = decimal.slice(0, precision)
        result = int + "." + decimal.replace(/0+$/, "")
        if (result.endsWith(".")) {
            result = result.slice(0, -1)
        }
    }

    result = result.toString()

    return result + chosenUnit
}