package asset

import "strings"

const (
	signalQualityExcellent = "信号很好"
	signalQualityNormal    = "信号正常"
	signalQualityWeak      = "信号较弱"
	signalQualityPoor      = "信号很差"
	signalQualityNoData    = "暂无数据"

	signalReasonWeakCoverage = "怀疑当前位置信号覆盖较弱"
	signalReasonInterference = "怀疑周围干扰较多"
	signalReasonBlocked      = "怀疑设备所处位置遮挡较强"
	signalReasonUnstable     = "怀疑网络环境不稳定"
	signalReasonUnknown      = "暂时无法判断"
)

// buildSignalSummary 根据四个原始信号指标输出统一的信号摘要。
func buildSignalSummary(rsrp, rsrq *int, rssi *string, sinr *int) (string, string) {
	score := 0
	seen := 0
	coverageBad := false
	interferenceBad := false
	blockedBad := false
	unstableBad := false

	if rsrp != nil {
		seen++
		switch {
		case *rsrp >= -90:
			score += 2
		case *rsrp >= -105:
			score += 1
		case *rsrp >= -115:
			score -= 1
			coverageBad = true
		default:
			score -= 2
			coverageBad = true
			blockedBad = true
		}
	}

	if rsrq != nil {
		seen++
		switch {
		case *rsrq >= -10:
			score += 2
		case *rsrq >= -15:
			score += 1
		case *rsrq >= -18:
			score -= 1
			interferenceBad = true
		default:
			score -= 2
			interferenceBad = true
			unstableBad = true
		}
	}

	if sinr != nil {
		seen++
		switch {
		case *sinr >= 20:
			score += 2
		case *sinr >= 13:
			score += 1
		case *sinr >= 5:
			score -= 1
			interferenceBad = true
		default:
			score -= 2
			interferenceBad = true
			unstableBad = true
		}
	}

	if rssiValue, ok := parseRSSI(rssi); ok {
		seen++
		switch {
		case rssiValue >= -65:
			score += 2
		case rssiValue >= -75:
			score += 1
		case rssiValue >= -85:
			score -= 1
			coverageBad = true
		default:
			score -= 2
			coverageBad = true
			blockedBad = true
		}
	}

	if seen == 0 {
		return signalQualityNoData, signalReasonUnknown
	}

	quality := signalQualityNormal
	switch {
	case score >= 6:
		quality = signalQualityExcellent
	case score >= 2:
		quality = signalQualityNormal
	case score >= -2:
		quality = signalQualityWeak
	default:
		quality = signalQualityPoor
	}

	if quality == signalQualityExcellent || quality == signalQualityNormal {
		return quality, signalReasonUnknown
	}

	switch {
	case blockedBad:
		return quality, signalReasonBlocked
	case interferenceBad:
		return quality, signalReasonInterference
	case coverageBad:
		return quality, signalReasonWeakCoverage
	case unstableBad:
		return quality, signalReasonUnstable
	default:
		return quality, signalReasonUnknown
	}
}

func parseRSSI(rssi *string) (int, bool) {
	if rssi == nil {
		return 0, false
	}
	value := strings.TrimSpace(*rssi)
	if value == "" {
		return 0, false
	}
	sign := 1
	number := 0
	started := false
	for i, ch := range value {
		if ch == '-' && i == 0 {
			sign = -1
			continue
		}
		if ch >= '0' && ch <= '9' {
			started = true
			number = number*10 + int(ch-'0')
			continue
		}
		if started {
			break
		}
	}
	if !started {
		return 0, false
	}
	return sign * number, true
}