package warningnotify

import (
	"fmt"
	"html"
	"strings"
	"time"
)

const warningEmailHTMLSignature = `data-warning-email="iotlcm"`

func applyContent(batch *Batch) {
	if batch == nil {
		return
	}
	switch batch.Method {
	case MethodSMS:
		batch.SMSContent = buildSMSContent(*batch)
	case MethodEmail:
		batch.EmailSubject = buildEmailSubject(*batch)
		batch.EmailBody = buildEmailBody(*batch)
	case MethodPlatform:
		batch.PlatformTitle = buildPlatformTitle(*batch)
		batch.PlatformContent = buildPlatformContent(*batch)
	}
}

func buildSMSContent(batch Batch) string {
	count := batchItemCount(batch)
	if count == 0 {
		return ""
	}

	summary := batchObjectSummary(batch)
	title := warningTitle(batch)
	action := ""
	if batchHasAffectOperation(batch) {
		action = "，涉及停机或断网操作"
	}

	return fmt.Sprintf(
		"【物联网】%s触发%s%s，请登录控制台查看。",
		summary,
		title,
		action,
	)
}

func buildEmailSubject(batch Batch) string {
	count := batchItemCount(batch)
	if count == 0 {
		return "物联网预警提醒"
	}
	return fmt.Sprintf("%s（%d条）", warningTitle(batch), count)
}

func buildEmailBody(batch Batch) string {
	count := batchItemCount(batch)
	if count == 0 {
		return ""
	}

	var builder strings.Builder
	builder.WriteString(`<div ` + warningEmailHTMLSignature + ` style="font-family:Arial,'Microsoft YaHei',sans-serif;font-size:14px;line-height:1.6;color:#1f2937;">`)
	fmt.Fprintf(&builder, `<p style="margin:0 0 12px;">%s，共 %d 条，最高级别：%s。</p>`, htmlEscape(warningTitle(batch)), count, htmlEscape(levelText(batchHighestLevel(batch))))
	if batchHasAffectOperation(batch) {
		builder.WriteString(`<p style="margin:0 0 12px;color:#b42318;">本次预警包含停机或断网类操作，请重点确认。</p>`)
	}
	builder.WriteString(`<table style="width:100%;border-collapse:collapse;border:1px solid #d0d5dd;">`)
	builder.WriteString(`<thead><tr style="background:#f2f4f7;">`)
	builder.WriteString(emailHeaderCell(emailObjectHeader(batch)))
	builder.WriteString(emailHeaderCell("预警类型"))
	builder.WriteString(emailHeaderCell("预警原因"))
	builder.WriteString(emailHeaderCell("预警时间"))
	builder.WriteString(`</tr></thead><tbody>`)
	for _, item := range batch.Items {
		builder.WriteString(`<tr>`)
		builder.WriteString(emailBodyCell(displayObjectCode(item)))
		builder.WriteString(emailBodyCell(emailWarningType(item, batch)))
		builder.WriteString(emailBodyCell(emailWarningReason(item)))
		builder.WriteString(emailBodyCell(emailWarnTime(item)))
		builder.WriteString(`</tr>`)
	}
	builder.WriteString(`</tbody></table></div>`)

	return strings.TrimSpace(builder.String())
}

func buildPlatformTitle(batch Batch) string {
	if len(batch.Items) == 0 {
		return "预警提醒"
	}
	if title := expireDayPlatformTitle(batch); title != "" {
		return title
	}
	return warningTitle(batch)
}

func buildPlatformContent(batch Batch) string {
	count := batchItemCount(batch)
	if count == 0 {
		return ""
	}

	content := buildPlatformSummaryContent(batch)
	if batchHasAffectOperation(batch) {
		content += "本次提醒包含停机或断网类操作，请及时确认。"
	}

	return content
}

func buildPlatformSummaryContent(batch Batch) string {
	if isExpireDayBatch(batch) {
		return fmt.Sprintf(
			"%s有%d张卡临近到期，最高档位：%s，请登录控制台查看。",
			firstObjectCode(batch),
			batchItemCount(batch),
			buildPlatformTitle(batch),
		)
	}
	return fmt.Sprintf(
		"%s触发%s，最高级别：%s，请登录控制台查看。",
		platformObjectSummary(batch),
		buildPlatformTitle(batch),
		levelText(batchHighestLevel(batch)),
	)
}

func warningTitle(batch Batch) string {
	category := warningCategory(batch)
	return categoryStageTitle(category, batch.WarnStage)
}

func warningCategory(batch Batch) string {
	category := strings.TrimSpace(batch.Category)
	if category == "" {
		category = "预警"
	}
	return category
}

func categoryStageTitle(category string, stage int) string {
	category = strings.TrimSpace(category)
	if category == "" {
		category = "预警"
	}
	if stage > 0 {
		return category + stageText(stage)
	}
	if strings.HasSuffix(category, "提醒") {
		return category
	}
	return category + "提醒"
}

func expireDayPlatformTitle(batch Batch) string {
	if !isExpireDayBatch(batch) {
		return ""
	}
	threshold := expireDayPlatformThreshold(batch)
	if threshold <= 0 {
		return "距离到期时间预警"
	}
	return fmt.Sprintf("距离到期时间小于%.0f天", threshold)
}

func isExpireDayBatch(batch Batch) bool {
	category := strings.TrimSpace(batch.Category)
	for _, item := range batch.Items {
		if strings.TrimSpace(item.Kind) == "expire_day" {
			return true
		}
		if strings.Contains(category, "到期") && strings.TrimSpace(item.UnitText) == "天" {
			return true
		}
	}
	return false
}

func expireDayPlatformThreshold(batch Batch) float64 {
	for _, item := range batch.Items {
		if item.WarnStage == batch.WarnStage && item.Threshold > 0 {
			return item.Threshold
		}
	}
	for _, item := range batch.Items {
		if item.Threshold > 0 {
			return item.Threshold
		}
	}
	switch batch.WarnStage {
	case 1:
		return 30
	case 2:
		return 15
	case 3:
		return 7
	default:
		return 0
	}
}

func itemDetailSummary(item Event) string {
	return itemSummary(item)
}

func batchObjectSummary(batch Batch) string {
	count := batchItemCount(batch)
	if count == 0 {
		return ""
	}
	code := firstObjectCode(batch)
	if count == 1 {
		return code
	}
	return fmt.Sprintf("%s等%d%s", code, count, objectCountUnit(batch.Items[0]))
}

func firstObjectCode(batch Batch) string {
	if len(batch.Items) == 0 {
		return "--"
	}
	return displayObjectCode(batch.Items[0])
}

func objectCountUnit(item Event) string {
	switch item.ItemType {
	case 2:
		return "个流量池"
	default:
		return "张卡"
	}
}

func metricSummary(item Event) string {
	unit := strings.TrimSpace(item.UnitText)
	switch unit {
	case "天", "月":
		parts := []string{
			"剩余" + formatMetric(item.Actual, unit),
		}
		if item.Threshold > 0 {
			parts = append(parts, "阈值"+formatMetric(item.Threshold, unit))
		}
		return strings.Join(parts, "，")
	case "%":
		parts := []string{
			"阈值" + formatMetric(item.Threshold, unit),
			"实际" + formatMetric(item.Actual, unit),
		}
		if shouldShowRemain(item) {
			parts = append(parts, "剩余"+remainMetric(item))
		}
		if item.TotalFlowMB > 0 {
			parts = append(parts, "总量"+formatMetric(item.TotalFlowMB, "MB"))
		}
		return strings.Join(parts, "，")
	default:
		parts := []string{
			"阈值" + formatMetric(item.Threshold, item.UnitText),
			"实际" + formatMetric(item.Actual, item.UnitText),
		}
		if shouldShowRemain(item) {
			parts = append(parts, "剩余"+remainMetric(item))
		}
		if item.TotalFlowMB > 0 {
			parts = append(parts, "总量"+formatMetric(item.TotalFlowMB, "MB"))
		}
		return strings.Join(parts, "，")
	}
}

func itemSummary(item Event) string {
	parts := make([]string, 0, 1)
	parts = append(parts, fmt.Sprintf("%s：%s", itemLabel(item), displayObjectCode(item)))
	return strings.Join(parts, "，")
}

func itemLabel(item Event) string {
	switch item.ItemType {
	case 2:
		return "流量池编号"
	default:
		return "ICCID"
	}
}

func displayObjectCode(item Event) string {
	itemCode := strings.TrimSpace(item.ItemCode)
	if itemCode == "" {
		return "--"
	}
	return itemCode
}

func stageText(stage int) string {
	if stage <= 0 {
		return ""
	}
	return fmt.Sprintf("第%d次提醒", stage)
}

func levelText(level int) string {
	switch level {
	case 1:
		return "提示"
	case 2:
		return "注意"
	case 3:
		return "警告"
	case 4:
		return "危险"
	case 5:
		return "紧急"
	default:
		return "提醒"
	}
}

func highestLevel(items []Event) int {
	level := 0
	for _, item := range items {
		if item.WarnLevel > level {
			level = item.WarnLevel
		}
	}
	return level
}

func hasAffectOperation(items []Event) bool {
	for _, item := range items {
		if item.AffectOperation {
			return true
		}
	}
	return false
}

func shouldShowRemain(item Event) bool {
	if item.TotalFlowMB > 0 {
		return true
	}
	unit := strings.TrimSpace(item.UnitText)
	return unit == "MB" || unit == "%"
}

func remainMetric(item Event) string {
	if !shouldShowRemain(item) {
		return "--"
	}
	return formatMetric(item.RemainFlowMB, "MB")
}

func formatMetric(value float64, unit string) string {
	unit = strings.TrimSpace(unit)
	switch unit {
	case "%":
		return fmt.Sprintf("%.2f%%", value)
	case "天", "月":
		return fmt.Sprintf("%.0f%s", value, unit)
	case "MB":
		return fmt.Sprintf("%.3f MB", value)
	default:
		if unit == "" {
			return fmt.Sprintf("%.3f", value)
		}
		return fmt.Sprintf("%.3f %s", value, unit)
	}
}

func formatTime(value time.Time) string {
	return value.Format("2006-01-02 15:04:05")
}

func emailObjectHeader(batch Batch) string {
	if len(batch.Items) == 0 {
		return "ICCID"
	}
	for _, item := range batch.Items {
		if item.ItemType != 2 {
			return "ICCID"
		}
	}
	return "流量池编号"
}

func emailWarningType(item Event, batch Batch) string {
	category := strings.TrimSpace(item.Category)
	if category != "" {
		return category
	}
	return warningCategory(batch)
}

func emailWarningReason(item Event) string {
	parts := make([]string, 0, 3)
	if item.WarnStage > 0 {
		parts = append(parts, stageText(item.WarnStage))
	}
	if summary := metricSummary(item); summary != "" {
		parts = append(parts, summary)
	}
	if item.OperationText != "" {
		parts = append(parts, item.OperationText)
	}
	if len(parts) == 0 && item.Remark != "" {
		parts = append(parts, item.Remark)
	}
	return strings.Join(parts, "，")
}

func emailWarnTime(item Event) string {
	if item.WarnTime.IsZero() {
		return "--"
	}
	return formatTime(item.WarnTime)
}

func emailHeaderCell(value string) string {
	return `<th style="padding:8px 10px;border:1px solid #d0d5dd;text-align:left;font-weight:600;color:#344054;">` + htmlEscape(value) + `</th>`
}

func emailBodyCell(value string) string {
	return `<td style="padding:8px 10px;border:1px solid #d0d5dd;vertical-align:top;color:#1f2937;">` + htmlEscape(value) + `</td>`
}

func htmlEscape(value string) string {
	value = strings.TrimSpace(value)
	if value == "" {
		return "--"
	}
	return html.EscapeString(value)
}

func platformObjectSummary(batch Batch) string {
	if len(batch.Items) == 0 {
		return ""
	}
	if batchItemCount(batch) > 5 {
		return fmt.Sprintf("\u5171%d%s", batchItemCount(batch), objectCountUnit(batch.Items[0]))
	}
	codes := make([]string, 0, len(batch.Items))
	for _, item := range batch.Items {
		codes = append(codes, displayObjectCode(item))
	}
	return strings.Join(codes, "\u3001")
}