package jrzq

import (
	"fmt"
	"math"
	"strconv"
)

// DecodeIntervalMidpoint 将 xyp 区间码解码为区间中位整数。
func DecodeIntervalMidpoint(field, code string) int {
	if code == "" || code == "0" {
		return 0
	}
	rules, ok := loanRiskIntervalMappings[field]
	if !ok {
		return 0
	}
	for _, rule := range rules {
		if rule.output != code {
			continue
		}
		min := rule.min
		max := rule.max
		if max >= math.MaxFloat64/4 {
			if rule.minInclusive {
				return int(math.Round(min + 1))
			}
			return int(math.Round(min + 2))
		}
		lo := min
		hi := max
		if !rule.minInclusive {
			lo += 0.5
		}
		if !rule.maxInclusive {
			hi -= 0.5
		}
		return int(math.Round((lo + hi) / 2))
	}
	return 0
}

// FormatLoanRiskInterval 将 xyp 区间码格式化为可读区间字符串。
func FormatLoanRiskInterval(field, code string) string {
	if code == "" || code == "0" {
		return "0"
	}
	rules, ok := loanRiskIntervalMappings[field]
	if !ok {
		return "0"
	}
	for _, rule := range rules {
		if rule.output != code {
			continue
		}
		return formatIntervalBounds(rule.min, rule.max, rule.minInclusive, rule.maxInclusive)
	}
	return "0"
}

func formatIntervalBounds(min, max float64, minInclusive, maxInclusive bool) string {
	if max >= math.MaxFloat64/4 {
		left := "("
		if minInclusive {
			left = "["
		}
		return fmt.Sprintf("%s%s,+)", left, formatBound(min))
	}
	left := "("
	if minInclusive {
		left = "["
	}
	right := ")"
	if maxInclusive {
		right = "]"
	}
	return fmt.Sprintf("%s%s,%s%s", left, formatBound(min), formatBound(max), right)
}

func formatBound(v float64) string {
	if v == float64(int64(v)) {
		return strconv.FormatInt(int64(v), 10)
	}
	return strconv.FormatFloat(v, 'f', -1, 64)
}