package messages

import (
	"errors"
	"fmt"
	"log/slog"
	"os"

	"gopkg.in/yaml.v3"
)

var ErrUnknownEvent = errors.New("unknown event type")

type Templates struct {
	templates map[string]string
}

func Load(path string) (*Templates, error) {
	t := &Templates{templates: defaultTemplates()}

	b, err := os.ReadFile(path)
	if err != nil {
		if os.IsNotExist(err) {
			slog.Warn("messages file not found, using embedded defaults", "path", path)
			return t, nil
		}
		return nil, fmt.Errorf("read messages file: %w", err)
	}

	parsed := map[string]string{}
	if err := yaml.Unmarshal(b, &parsed); err != nil {
		return nil, fmt.Errorf("parse messages file: %w", err)
	}

	for k, v := range parsed {
		t.templates[k] = v
	}
	return t, nil
}

func (t *Templates) Get(eventType string) (string, error) {
	tmpl, ok := t.templates[eventType]
	if !ok {
		return "", fmt.Errorf("%w: %s", ErrUnknownEvent, eventType)
	}
	return tmpl, nil
}

func (t *Templates) Has(eventType string) bool {
	_, ok := t.templates[eventType]
	return ok
}