/**
 * 把数字转换成可读的数字
 * 可以为小数和整数分别设置显示位数
 *
 * @example
 *  readableNumber(123456.789) // 123456.789
 *  readableNumber(123456.789, { fixedInt: 5 }) // 00123
 *  readableNumber(123456.789, { fixedInt: 5, fillString: "*" }) // ****1.22
 *
 * @param num
 * @param options.fixedInt 整数位数，不足补 0（根据 fillString），超出则不处理
 * @param options.fixedDecimal 小数位数，不足补 0，超出四舍五入
 * @param options.detailed 快速设置为适合详细对比数字信息的格式，相当于 fixedInt:4, fixedDecimal:3 fillString:" "
 * @param options.fillString  用于整数补位的符号，默认为 " "，如果为 "0" 会在有负号时把负号移到补位前
 */
export function readableNumber(
    num: number | string,
    options?: {
        fixedInt?: number
        fixedDecimal?: number
        detailed?: boolean
        fillString?: string
        unit?: "万" | "亿" | "千" | "K"
    }
) {
    if (num === undefined) return num

    let fixedInt = options?.fixedInt
    let fixedDecimal = options?.fixedDecimal
    let fillString = options?.fillString || "0"
    if (options?.detailed) {
        fixedInt = 4
        fixedDecimal = 3
        fillString = " "
    }

    if (fixedInt == undefined && fixedDecimal == undefined) {
        if (typeof num === "string") num = parseFloat(num)
        return num.toFixed(3)
    } else {
        let numStr = num.toString()
        let [int, decimal] = numStr.split(".")

        let fillIsZero = fillString === "0"

        if (fixedInt) {
            int = int.padStart(fixedInt, fillString)
        }

        // 00-2.00 -> -002.00
        if (fillIsZero) {
            let negativeIndex = int.indexOf("-")
            if (negativeIndex > 0) {
                int = "-" + int.slice(0, negativeIndex) + int.slice(negativeIndex + 1)
            }
        }

        if (fixedDecimal !== undefined) {
            if (decimal) {
                decimal = decimal.slice(0, fixedDecimal)
                if (decimal.length < fixedDecimal) {
                    decimal = decimal.padEnd(fixedDecimal, "0")
                } else {
                    decimal = parseFloat("0." + decimal)
                        .toFixed(fixedDecimal)
                        .split(".")[1]
                }
            } else {
                decimal = "0".repeat(fixedDecimal)
            }
        }

        return decimal ? `${int}.${decimal}` : int
    }
}