package babble

import (
	"dk/internal/store"
	"fmt"
	"sort"
	"strings"
	"sync"
	"time"
)

// Babble represents a global chat message in the game
type Babble struct {
	ID     int    `json:"id"`
	Posted int64  `json:"posted"`
	Author string `json:"author"`
	Babble string `json:"babble"`
}

func (b *Babble) Save() error {
	babbleStore := GetStore()
	babbleStore.UpdateBabble(b)
	return nil
}

func (b *Babble) Delete() error {
	babbleStore := GetStore()
	babbleStore.RemoveBabble(b.ID)
	return nil
}

// Creates a new Babble with sensible defaults
func New() *Babble {
	return &Babble{
		Posted: time.Now().Unix(),
		Author: "",
		Babble: "",
	}
}

// Validate checks if babble has valid values
func (b *Babble) Validate() error {
	if b.Posted <= 0 {
		return fmt.Errorf("babble Posted timestamp must be positive")
	}
	if strings.TrimSpace(b.Author) == "" {
		return fmt.Errorf("babble Author cannot be empty")
	}
	if strings.TrimSpace(b.Babble) == "" {
		return fmt.Errorf("babble message cannot be empty")
	}
	return nil
}

// BabbleStore provides in-memory storage with O(1) lookups and babble-specific indices
type BabbleStore struct {
	*store.BaseStore[Babble]                  // Embedded generic store
	byAuthor                 map[string][]int // Author (lowercase) -> []ID
	allByPosted              []int            // All IDs sorted by posted DESC, id DESC
	mu                       sync.RWMutex     // Protects indices
}

// Global in-memory store
var babbleStore *BabbleStore
var storeOnce sync.Once

// Initialize the in-memory store
func initStore() {
	babbleStore = &BabbleStore{
		BaseStore:   store.NewBaseStore[Babble](),
		byAuthor:    make(map[string][]int),
		allByPosted: make([]int, 0),
	}
}

// GetStore returns the global babble store
func GetStore() *BabbleStore {
	storeOnce.Do(initStore)
	return babbleStore
}

// AddBabble adds a babble message to the in-memory store and updates all indices
func (bs *BabbleStore) AddBabble(babble *Babble) {
	bs.mu.Lock()
	defer bs.mu.Unlock()

	// Validate babble
	if err := babble.Validate(); err != nil {
		return
	}

	// Add to base store
	bs.Add(babble.ID, babble)

	// Rebuild indices
	bs.rebuildIndicesUnsafe()
}

// RemoveBabble removes a babble message from the store and updates indices
func (bs *BabbleStore) RemoveBabble(id int) {
	bs.mu.Lock()
	defer bs.mu.Unlock()

	// Remove from base store
	bs.Remove(id)

	// Rebuild indices
	bs.rebuildIndicesUnsafe()
}

// UpdateBabble updates a babble message efficiently
func (bs *BabbleStore) UpdateBabble(babble *Babble) {
	bs.mu.Lock()
	defer bs.mu.Unlock()

	// Validate babble
	if err := babble.Validate(); err != nil {
		return
	}

	// Update base store
	bs.Add(babble.ID, babble)

	// Rebuild indices
	bs.rebuildIndicesUnsafe()
}

// LoadData loads babble data from JSON file, or starts with empty store
func LoadData(dataPath string) error {
	bs := GetStore()

	// Load from base store, which handles JSON loading
	if err := bs.BaseStore.LoadData(dataPath); err != nil {
		return err
	}

	// Rebuild indices from loaded data
	bs.rebuildIndices()
	return nil
}

// SaveData saves babble data to JSON file
func SaveData(dataPath string) error {
	bs := GetStore()
	return bs.BaseStore.SaveData(dataPath)
}

// rebuildIndicesUnsafe rebuilds all indices from base store data (caller must hold lock)
func (bs *BabbleStore) rebuildIndicesUnsafe() {
	// Clear indices
	bs.byAuthor = make(map[string][]int)
	bs.allByPosted = make([]int, 0)

	// Collect all babbles and build indices
	allBabbles := bs.GetAll()

	for id, babble := range allBabbles {
		// Author index (case-insensitive)
		authorKey := strings.ToLower(babble.Author)
		bs.byAuthor[authorKey] = append(bs.byAuthor[authorKey], id)

		// All IDs
		bs.allByPosted = append(bs.allByPosted, id)
	}

	// Sort allByPosted by posted DESC, then ID DESC
	sort.Slice(bs.allByPosted, func(i, j int) bool {
		babbleI, _ := bs.GetByID(bs.allByPosted[i])
		babbleJ, _ := bs.GetByID(bs.allByPosted[j])
		if babbleI.Posted != babbleJ.Posted {
			return babbleI.Posted > babbleJ.Posted // DESC
		}
		return bs.allByPosted[i] > bs.allByPosted[j] // DESC
	})

	// Sort author indices by posted DESC, then ID DESC
	for author := range bs.byAuthor {
		sort.Slice(bs.byAuthor[author], func(i, j int) bool {
			babbleI, _ := bs.GetByID(bs.byAuthor[author][i])
			babbleJ, _ := bs.GetByID(bs.byAuthor[author][j])
			if babbleI.Posted != babbleJ.Posted {
				return babbleI.Posted > babbleJ.Posted // DESC
			}
			return bs.byAuthor[author][i] > bs.byAuthor[author][j] // DESC
		})
	}
}

// rebuildIndices rebuilds all babble-specific indices from base store data
func (bs *BabbleStore) rebuildIndices() {
	bs.mu.Lock()
	defer bs.mu.Unlock()
	bs.rebuildIndicesUnsafe()
}

// Retrieves a babble message by ID
func Find(id int) (*Babble, error) {
	bs := GetStore()
	babble, exists := bs.GetByID(id)
	if !exists {
		return nil, fmt.Errorf("babble with ID %d not found", id)
	}
	return babble, nil
}

// Retrieves all babble messages ordered by posted time (newest first)
func All() ([]*Babble, error) {
	bs := GetStore()
	bs.mu.RLock()
	defer bs.mu.RUnlock()

	result := make([]*Babble, 0, len(bs.allByPosted))
	for _, id := range bs.allByPosted {
		if babble, exists := bs.GetByID(id); exists {
			result = append(result, babble)
		}
	}
	return result, nil
}

// Retrieves babble messages by a specific author
func ByAuthor(author string) ([]*Babble, error) {
	bs := GetStore()
	bs.mu.RLock()
	defer bs.mu.RUnlock()

	ids, exists := bs.byAuthor[strings.ToLower(author)]
	if !exists {
		return []*Babble{}, nil
	}

	result := make([]*Babble, 0, len(ids))
	for _, id := range ids {
		if babble, exists := bs.GetByID(id); exists {
			result = append(result, babble)
		}
	}
	return result, nil
}

// Retrieves the most recent babble messages (limited by count)
func Recent(limit int) ([]*Babble, error) {
	bs := GetStore()
	bs.mu.RLock()
	defer bs.mu.RUnlock()

	if limit > len(bs.allByPosted) {
		limit = len(bs.allByPosted)
	}

	result := make([]*Babble, 0, limit)
	for i := 0; i < limit; i++ {
		if babble, exists := bs.GetByID(bs.allByPosted[i]); exists {
			result = append(result, babble)
		}
	}
	return result, nil
}

// Retrieves babble messages since a specific timestamp
func Since(since int64) ([]*Babble, error) {
	bs := GetStore()
	bs.mu.RLock()
	defer bs.mu.RUnlock()

	var result []*Babble
	for _, id := range bs.allByPosted {
		if babble, exists := bs.GetByID(id); exists && babble.Posted >= since {
			result = append(result, babble)
		}
	}
	return result, nil
}

// Retrieves babble messages between two timestamps (inclusive)
func Between(start, end int64) ([]*Babble, error) {
	bs := GetStore()
	bs.mu.RLock()
	defer bs.mu.RUnlock()

	var result []*Babble
	for _, id := range bs.allByPosted {
		if babble, exists := bs.GetByID(id); exists && babble.Posted >= start && babble.Posted <= end {
			result = append(result, babble)
		}
	}
	return result, nil
}

// Retrieves babble messages containing the search term (case-insensitive)
func Search(term string) ([]*Babble, error) {
	bs := GetStore()
	bs.mu.RLock()
	defer bs.mu.RUnlock()

	var result []*Babble
	lowerTerm := strings.ToLower(term)

	for _, id := range bs.allByPosted {
		if babble, exists := bs.GetByID(id); exists {
			if strings.Contains(strings.ToLower(babble.Babble), lowerTerm) {
				result = append(result, babble)
			}
		}
	}
	return result, nil
}

// Retrieves recent messages from a specific author
func RecentByAuthor(author string, limit int) ([]*Babble, error) {
	bs := GetStore()
	bs.mu.RLock()
	defer bs.mu.RUnlock()

	ids, exists := bs.byAuthor[strings.ToLower(author)]
	if !exists {
		return []*Babble{}, nil
	}

	if limit > len(ids) {
		limit = len(ids)
	}

	result := make([]*Babble, 0, limit)
	for i := 0; i < limit; i++ {
		if babble, exists := bs.GetByID(ids[i]); exists {
			result = append(result, babble)
		}
	}
	return result, nil
}

// Saves a new babble to the in-memory store and sets the ID
func (b *Babble) Insert() error {
	bs := GetStore()

	// Validate before insertion
	if err := b.Validate(); err != nil {
		return fmt.Errorf("validation failed: %w", err)
	}

	// Assign new ID if not set
	if b.ID == 0 {
		b.ID = bs.GetNextID()
	}

	// Add to store
	bs.AddBabble(b)
	return nil
}

// Returns the posted timestamp as a time.Time
func (b *Babble) PostedTime() time.Time {
	return time.Unix(b.Posted, 0)
}

// Sets the posted timestamp from a time.Time
func (b *Babble) SetPostedTime(t time.Time) {
	b.Posted = t.Unix()
}

// Returns true if the babble message was posted within the last hour
func (b *Babble) IsRecent() bool {
	return time.Since(b.PostedTime()) < time.Hour
}

// Returns how long ago the babble message was posted
func (b *Babble) Age() time.Duration {
	return time.Since(b.PostedTime())
}

// Returns true if the given username is the author of this babble message
func (b *Babble) IsAuthor(username string) bool {
	return strings.EqualFold(b.Author, username)
}

// Returns a truncated version of the babble for previews
func (b *Babble) Preview(maxLength int) string {
	if len(b.Babble) <= maxLength {
		return b.Babble
	}

	if maxLength < 3 {
		return b.Babble[:maxLength]
	}

	return b.Babble[:maxLength-3] + "..."
}

// Returns the number of words in the babble message
func (b *Babble) WordCount() int {
	if b.Babble == "" {
		return 0
	}

	// Simple word count by splitting on whitespace
	words := 0
	inWord := false

	for _, char := range b.Babble {
		if char == ' ' || char == '\t' || char == '\n' || char == '\r' {
			if inWord {
				words++
				inWord = false
			}
		} else {
			inWord = true
		}
	}

	if inWord {
		words++
	}

	return words
}

// Returns the character length of the babble message
func (b *Babble) Length() int {
	return len(b.Babble)
}

// Returns true if the babble message contains the given term (case-insensitive)
func (b *Babble) Contains(term string) bool {
	return strings.Contains(strings.ToLower(b.Babble), strings.ToLower(term))
}

// Returns true if the babble message is empty or whitespace-only
func (b *Babble) IsEmpty() bool {
	return strings.TrimSpace(b.Babble) == ""
}

// Returns true if the message exceeds the typical chat length
func (b *Babble) IsLongMessage(threshold int) bool {
	return b.Length() > threshold
}

// Returns a slice of usernames mentioned in the message (starting with @)
func (b *Babble) GetMentions() []string {
	words := strings.Fields(b.Babble)
	var mentions []string

	for _, word := range words {
		if strings.HasPrefix(word, "@") && len(word) > 1 {
			// Clean up punctuation from the end
			mention := strings.TrimRight(word[1:], ".,!?;:")
			if mention != "" {
				mentions = append(mentions, mention)
			}
		}
	}

	return mentions
}

// Returns true if the message mentions the given username
func (b *Babble) HasMention(username string) bool {
	mentions := b.GetMentions()
	for _, mention := range mentions {
		if strings.EqualFold(mention, username) {
			return true
		}
	}
	return false
}