// Package alert extracts a readable title and severity from Grafana and
// Alertmanager webhook bodies without hiding the raw payload.
package alert

import (
	"encoding/json"
	"strings"
)

// TitleSeverity returns the list title and a severity/status string.
// An ntfy title wins; otherwise Grafana's title or alertname is used.
func TitleSeverity(ntfyTitle, body string) (string, string) {
	title := strings.TrimSpace(ntfyTitle)
	obj, ok := object(body)
	sev := ""
	if ok {
		labels, _ := obj["commonLabels"].(map[string]any)
		if title == "" {
			title = strings.TrimSpace(str(obj["title"]))
			if title == "" {
				title = strings.TrimSpace(str(labels["alertname"]))
			}
		}
		sev = strings.TrimSpace(str(obj["status"]))
		if sev == "" {
			sev = strings.TrimSpace(str(labels["severity"]))
		}
	}
	if title == "" {
		body = strings.TrimSpace(body)
		if body == "" {
			title = "(empty)"
		} else {
			title = strings.Split(body, "\n")[0]
		}
	}
	return title, sev
}

// Tone picks a color role. An explicit severity wins over ntfy priority.
func Tone(sev string, priority int) string {
	s := strings.ToLower(sev)
	switch {
	case s == "firing" || s == "critical" || s == "error" || strings.Contains(s, "critical") || strings.Contains(s, "error"):
		return "bad"
	case s == "resolved" || s == "ok" || s == "success" || s == "info" || strings.Contains(s, "resolved"):
		return "ok"
	case s != "":
		return "warn"
	case priority >= 5:
		return "bad"
	case priority == 4:
		return "warn"
	case priority > 0 && priority < 3:
		return "dim"
	default:
		return "base"
	}
}

// BodyView renders an alert webhook as text, or pretty JSON for other objects.
// raw forces pretty JSON when the body is JSON.
func BodyView(body string, raw bool) string {
	obj, ok := object(body)
	if !ok {
		return body
	}
	if !raw && isAlert(obj) {
		return readable(obj)
	}
	enc, err := json.MarshalIndent(obj, "", "  ")
	if err != nil {
		return body
	}
	return string(enc)
}

func object(body string) (map[string]any, bool) {
	var v any
	if err := json.Unmarshal([]byte(body), &v); err != nil {
		return nil, false
	}
	obj, ok := v.(map[string]any)
	return obj, ok
}

func isAlert(obj map[string]any) bool {
	_, labels := obj["commonLabels"]
	_, alerts := obj["alerts"]
	_, ann := obj["commonAnnotations"]
	return labels || alerts || ann
}

func readable(obj map[string]any) string {
	labels, _ := obj["commonLabels"].(map[string]any)
	ann, _ := obj["commonAnnotations"].(map[string]any)
	var b strings.Builder
	writeKV(&b, "status", str(obj["status"]))
	writeKV(&b, "alert", str(labels["alertname"]))
	writeKV(&b, "severity", str(labels["severity"]))
	writeKV(&b, "summary", str(ann["summary"]))
	writeKV(&b, "description", str(ann["description"]))
	alerts, _ := obj["alerts"].([]any)
	if len(alerts) > 0 {
		if b.Len() > 0 {
			b.WriteByte('\n')
		}
		b.WriteString("alerts:\n")
		for _, item := range alerts {
			alert, _ := item.(map[string]any)
			al, _ := alert["labels"].(map[string]any)
			aa, _ := alert["annotations"].(map[string]any)
			name := str(al["alertname"])
			if name == "" {
				name = "(alert)"
			}
			b.WriteString("- [" + str(alert["status"]) + "] " + name + "\n")
			if s := str(aa["summary"]); s != "" {
				b.WriteString("  summary: " + s + "\n")
			}
			if s := str(aa["description"]); s != "" {
				b.WriteString("  description: " + s + "\n")
			}
		}
	}
	return strings.TrimRight(b.String(), "\n")
}

func writeKV(b *strings.Builder, k, v string) {
	if v == "" {
		return
	}
	b.WriteString(k + ": " + v + "\n")
}

func str(v any) string {
	s, _ := v.(string)
	return s
}