// Package store keeps an in-memory, newest-first view of ntfy messages.
package store

import (
	"strings"
	"sync"
)

// Attachment is a file linked from a message.
type Attachment struct {
	Name string
	URL  string
	Type string
	Size int64
}

// Message is one delivered ntfy notification.
type Message struct {
	ID         string
	Time       int64
	Expires    int64
	Topic      string
	Title      string
	Body       string
	Tags       []string
	Priority   int
	Click      string
	Attachment *Attachment
	Actions    string
}

// Store is safe for concurrent readers and writers.
type Store struct {
	mu      sync.Mutex
	byTopic map[string][]Message
	index   map[string]string
	order   []string
}

// New returns an empty store.
func New() *Store {
	return &Store{
		byTopic: map[string][]Message{},
		index:   map[string]string{},
	}
}

// Put inserts a message. A repeated id is ignored.
func (s *Store) Put(m Message) {
	s.mu.Lock()
	defer s.mu.Unlock()
	if m.ID != "" {
		if _, ok := s.index[m.ID]; ok {
			return
		}
		s.index[m.ID] = m.Topic
	}
	s.ensure(m.Topic)
	s.byTopic[m.Topic] = insertNewest(s.byTopic[m.Topic], m)
}

// Delete removes the message with id.
func (s *Store) Delete(id string) {
	s.mu.Lock()
	defer s.mu.Unlock()
	topic, ok := s.index[id]
	if !ok {
		return
	}
	list := s.byTopic[topic]
	for i, m := range list {
		if m.ID == id {
			s.byTopic[topic] = append(list[:i], list[i+1:]...)
			break
		}
	}
	delete(s.index, id)
}

// Clear removes every message for a topic.
func (s *Store) Clear(topic string) {
	s.mu.Lock()
	defer s.mu.Unlock()
	for _, m := range s.byTopic[topic] {
		if m.ID != "" {
			delete(s.index, m.ID)
		}
	}
	s.byTopic[topic] = nil
}

// List returns a copy of one topic, newest first.
func (s *Store) List(topic string) []Message {
	s.mu.Lock()
	defer s.mu.Unlock()
	src := s.byTopic[topic]
	out := make([]Message, len(src))
	copy(out, src)
	return out
}

// Topics returns topic names in the order they were first seen.
func (s *Store) Topics() []string {
	s.mu.Lock()
	defer s.mu.Unlock()
	out := make([]string, len(s.order))
	copy(out, s.order)
	return out
}

func (s *Store) ensure(topic string) {
	if _, ok := s.byTopic[topic]; ok {
		return
	}
	s.byTopic[topic] = nil
	s.order = append(s.order, topic)
}

func insertNewest(list []Message, m Message) []Message {
	i := 0
	for i < len(list) && list[i].Time > m.Time {
		i++
	}
	list = append(list, Message{})
	copy(list[i+1:], list[i:])
	list[i] = m
	return list
}

// Match reports whether needle is contained in the message's visible fields.
func Match(m Message, title, needle string) bool {
	needle = strings.ToLower(strings.TrimSpace(needle))
	if needle == "" {
		return true
	}
	hay := strings.ToLower(strings.Join([]string{
		title,
		m.Title,
		m.Body,
		m.ID,
		strings.Join(m.Tags, " "),
	}, " "))
	return strings.Contains(hay, needle)
}