package spells

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

// Spell represents a spell in the game
type Spell struct {
	ID        int    `json:"id"`
	Name      string `json:"name"`
	MP        int    `json:"mp"`
	Attribute int    `json:"attribute"`
	Type      int    `json:"type"`
}

func (s *Spell) Save() error {
	spellStore := GetStore()
	spellStore.UpdateSpell(s)
	return nil
}

func (s *Spell) Delete() error {
	spellStore := GetStore()
	spellStore.RemoveSpell(s.ID)
	return nil
}

// Creates a new Spell with sensible defaults
func New() *Spell {
	return &Spell{
		Name:      "",
		MP:        5,           // Default MP cost
		Attribute: 10,          // Default attribute value
		Type:      TypeHealing, // Default to healing spell
	}
}

// Validate checks if spell has valid values
func (s *Spell) Validate() error {
	if s.Name == "" {
		return fmt.Errorf("spell name cannot be empty")
	}
	if s.MP < 0 {
		return fmt.Errorf("spell MP cannot be negative")
	}
	if s.Attribute < 0 {
		return fmt.Errorf("spell Attribute cannot be negative")
	}
	if s.Type < TypeHealing || s.Type > TypeDefenseBoost {
		return fmt.Errorf("invalid spell type: %d", s.Type)
	}
	return nil
}

// SpellType constants for spell types
const (
	TypeHealing      = 1
	TypeHurt         = 2
	TypeSleep        = 3
	TypeAttackBoost  = 4
	TypeDefenseBoost = 5
)

// SpellStore provides in-memory storage with O(1) lookups and spell-specific indices
type SpellStore struct {
	*store.BaseStore[Spell]                // Embedded generic store
	byType                  map[int][]int  // Type -> []ID
	byName                  map[string]int // Name (lowercase) -> ID
	byMP                    map[int][]int  // MP -> []ID
	allByTypeMP             []int          // All IDs sorted by type, MP, ID
	mu                      sync.RWMutex   // Protects indices
}

// Global in-memory store
var spellStore *SpellStore
var storeOnce sync.Once

// Initialize the in-memory store
func initStore() {
	spellStore = &SpellStore{
		BaseStore:   store.NewBaseStore[Spell](),
		byType:      make(map[int][]int),
		byName:      make(map[string]int),
		byMP:        make(map[int][]int),
		allByTypeMP: make([]int, 0),
	}
}

// GetStore returns the global spell store
func GetStore() *SpellStore {
	storeOnce.Do(initStore)
	return spellStore
}

// AddSpell adds a spell to the in-memory store and updates all indices
func (ss *SpellStore) AddSpell(spell *Spell) {
	ss.mu.Lock()
	defer ss.mu.Unlock()

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

	// Add to base store
	ss.Add(spell.ID, spell)

	// Rebuild indices
	ss.rebuildIndicesUnsafe()
}

// RemoveSpell removes a spell from the store and updates indices
func (ss *SpellStore) RemoveSpell(id int) {
	ss.mu.Lock()
	defer ss.mu.Unlock()

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

	// Rebuild indices
	ss.rebuildIndicesUnsafe()
}

// UpdateSpell updates a spell efficiently
func (ss *SpellStore) UpdateSpell(spell *Spell) {
	ss.mu.Lock()
	defer ss.mu.Unlock()

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

	// Update base store
	ss.Add(spell.ID, spell)

	// Rebuild indices
	ss.rebuildIndicesUnsafe()
}

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

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

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

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

// rebuildIndicesUnsafe rebuilds all indices from base store data (caller must hold lock)
func (ss *SpellStore) rebuildIndicesUnsafe() {
	// Clear indices
	ss.byType = make(map[int][]int)
	ss.byName = make(map[string]int)
	ss.byMP = make(map[int][]int)
	ss.allByTypeMP = make([]int, 0)

	// Collect all spells and build indices
	allSpells := ss.GetAll()

	for id, spell := range allSpells {
		// Type index
		ss.byType[spell.Type] = append(ss.byType[spell.Type], id)

		// Name index (case-insensitive)
		ss.byName[strings.ToLower(spell.Name)] = id

		// MP index
		ss.byMP[spell.MP] = append(ss.byMP[spell.MP], id)

		// All IDs
		ss.allByTypeMP = append(ss.allByTypeMP, id)
	}

	// Sort allByTypeMP by type, then MP, then ID
	sort.Slice(ss.allByTypeMP, func(i, j int) bool {
		spellI, _ := ss.GetByID(ss.allByTypeMP[i])
		spellJ, _ := ss.GetByID(ss.allByTypeMP[j])
		if spellI.Type != spellJ.Type {
			return spellI.Type < spellJ.Type
		}
		if spellI.MP != spellJ.MP {
			return spellI.MP < spellJ.MP
		}
		return ss.allByTypeMP[i] < ss.allByTypeMP[j]
	})

	// Sort type indices by MP, then ID
	for spellType := range ss.byType {
		sort.Slice(ss.byType[spellType], func(i, j int) bool {
			spellI, _ := ss.GetByID(ss.byType[spellType][i])
			spellJ, _ := ss.GetByID(ss.byType[spellType][j])
			if spellI.MP != spellJ.MP {
				return spellI.MP < spellJ.MP
			}
			return ss.byType[spellType][i] < ss.byType[spellType][j]
		})
	}

	// Sort MP indices by type, then ID
	for mp := range ss.byMP {
		sort.Slice(ss.byMP[mp], func(i, j int) bool {
			spellI, _ := ss.GetByID(ss.byMP[mp][i])
			spellJ, _ := ss.GetByID(ss.byMP[mp][j])
			if spellI.Type != spellJ.Type {
				return spellI.Type < spellJ.Type
			}
			return ss.byMP[mp][i] < ss.byMP[mp][j]
		})
	}
}

// rebuildIndices rebuilds all spell-specific indices from base store data
func (ss *SpellStore) rebuildIndices() {
	ss.mu.Lock()
	defer ss.mu.Unlock()
	ss.rebuildIndicesUnsafe()
}

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

// Retrieves all spells
func All() ([]*Spell, error) {
	ss := GetStore()
	ss.mu.RLock()
	defer ss.mu.RUnlock()

	result := make([]*Spell, 0, len(ss.allByTypeMP))
	for _, id := range ss.allByTypeMP {
		if spell, exists := ss.GetByID(id); exists {
			result = append(result, spell)
		}
	}
	return result, nil
}

// Retrieves spells by type
func ByType(spellType int) ([]*Spell, error) {
	ss := GetStore()
	ss.mu.RLock()
	defer ss.mu.RUnlock()

	ids, exists := ss.byType[spellType]
	if !exists {
		return []*Spell{}, nil
	}

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

// Retrieves spells that cost at most the specified MP
func ByMaxMP(maxMP int) ([]*Spell, error) {
	ss := GetStore()
	ss.mu.RLock()
	defer ss.mu.RUnlock()

	var result []*Spell
	for mp := 0; mp <= maxMP; mp++ {
		if ids, exists := ss.byMP[mp]; exists {
			for _, id := range ids {
				if spell, exists := ss.GetByID(id); exists {
					result = append(result, spell)
				}
			}
		}
	}
	return result, nil
}

// Retrieves spells of a specific type that cost at most the specified MP
func ByTypeAndMaxMP(spellType, maxMP int) ([]*Spell, error) {
	ss := GetStore()
	ss.mu.RLock()
	defer ss.mu.RUnlock()

	ids, exists := ss.byType[spellType]
	if !exists {
		return []*Spell{}, nil
	}

	var result []*Spell
	for _, id := range ids {
		if spell, exists := ss.GetByID(id); exists && spell.MP <= maxMP {
			result = append(result, spell)
		}
	}
	return result, nil
}

// Retrieves a spell by name (case-insensitive)
func ByName(name string) (*Spell, error) {
	ss := GetStore()
	ss.mu.RLock()
	defer ss.mu.RUnlock()

	id, exists := ss.byName[strings.ToLower(name)]
	if !exists {
		return nil, fmt.Errorf("spell with name '%s' not found", name)
	}

	spell, exists := ss.GetByID(id)
	if !exists {
		return nil, fmt.Errorf("spell with name '%s' not found", name)
	}

	return spell, nil
}

// Saves a new spell to the in-memory store and sets the ID
func (s *Spell) Insert() error {
	ss := GetStore()

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

	// Assign new ID if not set
	if s.ID == 0 {
		s.ID = ss.GetNextID()
	}

	// Add to store
	ss.AddSpell(s)
	return nil
}

// Returns true if the spell is a healing spell
func (s *Spell) IsHealing() bool {
	return s.Type == TypeHealing
}

// Returns true if the spell is a hurt spell
func (s *Spell) IsHurt() bool {
	return s.Type == TypeHurt
}

// Returns true if the spell is a sleep spell
func (s *Spell) IsSleep() bool {
	return s.Type == TypeSleep
}

// Returns true if the spell boosts attack
func (s *Spell) IsAttackBoost() bool {
	return s.Type == TypeAttackBoost
}

// Returns true if the spell boosts defense
func (s *Spell) IsDefenseBoost() bool {
	return s.Type == TypeDefenseBoost
}

// Returns the string representation of the spell type
func (s *Spell) TypeName() string {
	switch s.Type {
	case TypeHealing:
		return "Healing"
	case TypeHurt:
		return "Hurt"
	case TypeSleep:
		return "Sleep"
	case TypeAttackBoost:
		return "Attack Boost"
	case TypeDefenseBoost:
		return "Defense Boost"
	default:
		return "Unknown"
	}
}

// Returns true if the spell can be cast with the given MP
func (s *Spell) CanCast(availableMP int) bool {
	return availableMP >= s.MP
}

// Returns the attribute per MP ratio (higher is more efficient)
func (s *Spell) Efficiency() float64 {
	if s.MP == 0 {
		return 0
	}
	return float64(s.Attribute) / float64(s.MP)
}

// Returns true if the spell is used for attacking
func (s *Spell) IsOffensive() bool {
	return s.Type == TypeHurt || s.Type == TypeSleep
}

// Returns true if the spell is used for support/buffs
func (s *Spell) IsSupport() bool {
	return s.Type == TypeHealing || s.Type == TypeAttackBoost || s.Type == TypeDefenseBoost
}