package notify

import (
	"context"
	"fmt"
	"io"
	"net/http"
	"strings"
	"time"
)

// NtfyNotifier posts to ntfy.sh (or a self-hosted ntfy server). Message
// body is the plain text body; title and URL are passed via X-Title and
// X-Click headers so ntfy renders them as the push title + deep link.
type NtfyNotifier struct {
	NameStr string
	Server  string // e.g. "https://ntfy.sh" or self-hosted
	Topic   string
	HTTP    *http.Client
}

func NewNtfy(name, server, topic string) *NtfyNotifier {
	if server == "" {
		server = "https://ntfy.sh"
	}
	return &NtfyNotifier{
		NameStr: name,
		Server:  strings.TrimRight(server, "/"),
		Topic:   topic,
		HTTP:    &http.Client{Timeout: 10 * time.Second},
	}
}

func (n *NtfyNotifier) Name() string { return n.NameStr }

func (n *NtfyNotifier) Send(ctx context.Context, ev Event) error {
	if n.Topic == "" {
		return fmt.Errorf("ntfy: no topic configured")
	}
	url := n.Server + "/" + n.Topic
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, strings.NewReader(ev.Body))
	if err != nil {
		return err
	}
	if ev.Title != "" {
		req.Header.Set("X-Title", ev.Title)
	}
	if ev.URL != "" {
		req.Header.Set("X-Click", ev.URL)
	}
	req.Header.Set("X-Priority", priorityForSeverity(ev.Severity))
	req.Header.Set("X-Tags", ntfyTag(ev.Kind, ev.Severity))

	resp, err := n.HTTP.Do(req)
	if err != nil {
		return err
	}
	defer func() { _ = resp.Body.Close() }()
	if resp.StatusCode >= 300 {
		b, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("ntfy: %d: %s", resp.StatusCode, strings.TrimSpace(string(b)))
	}
	return nil
}

// priorityForSeverity maps our severities to ntfy's 1–5 scale. "info"
// → 3 (default), warning → 4, critical → 5.
func priorityForSeverity(s Severity) string {
	switch s {
	case SeverityCritical:
		return "5"
	case SeverityWarning:
		return "4"
	default:
		return "3"
	}
}

func ntfyTag(k Kind, s Severity) string {
	switch {
	case s == SeverityCritical:
		return "rotating_light," + string(k)
	case k == KindRunCompleted:
		return "white_check_mark," + string(k)
	case k == KindHoldingOpened:
		return "construction," + string(k)
	default:
		return string(k)
	}
}