Dragon-Knight/internal/monsters/monsters.go

package monsters

import (
	"fmt"

	"dk/internal/database"
	"zombiezen.com/go/sqlite"
)

// Monster represents a monster in the database
type Monster struct {
	ID      int    `json:"id"`
	Name    string `json:"name"`
	MaxHP   int    `json:"max_hp"`
	MaxDmg  int    `json:"max_dmg"`
	Armor   int    `json:"armor"`
	Level   int    `json:"level"`
	MaxExp  int    `json:"max_exp"`
	MaxGold int    `json:"max_gold"`
	Immune  int    `json:"immune"`
	
	db *database.DB
}

// Immunity constants for monster immunity types
const (
	ImmuneNone   = 0
	ImmuneHurt   = 1  // Immune to Hurt spells
	ImmuneSleep  = 2  // Immune to Sleep spells
)

// Find retrieves a monster by ID
func Find(db *database.DB, id int) (*Monster, error) {
	monster := &Monster{db: db}
	
	query := "SELECT id, name, max_hp, max_dmg, armor, level, max_exp, max_gold, immune FROM monsters WHERE id = ?"
	err := db.Query(query, func(stmt *sqlite.Stmt) error {
		monster.ID = stmt.ColumnInt(0)
		monster.Name = stmt.ColumnText(1)
		monster.MaxHP = stmt.ColumnInt(2)
		monster.MaxDmg = stmt.ColumnInt(3)
		monster.Armor = stmt.ColumnInt(4)
		monster.Level = stmt.ColumnInt(5)
		monster.MaxExp = stmt.ColumnInt(6)
		monster.MaxGold = stmt.ColumnInt(7)
		monster.Immune = stmt.ColumnInt(8)
		return nil
	}, id)
	
	if err != nil {
		return nil, fmt.Errorf("failed to find monster: %w", err)
	}
	
	if monster.ID == 0 {
		return nil, fmt.Errorf("monster with ID %d not found", id)
	}
	
	return monster, nil
}

// All retrieves all monsters
func All(db *database.DB) ([]*Monster, error) {
	var monsters []*Monster
	
	query := "SELECT id, name, max_hp, max_dmg, armor, level, max_exp, max_gold, immune FROM monsters ORDER BY level, id"
	err := db.Query(query, func(stmt *sqlite.Stmt) error {
		monster := &Monster{
			ID:      stmt.ColumnInt(0),
			Name:    stmt.ColumnText(1),
			MaxHP:   stmt.ColumnInt(2),
			MaxDmg:  stmt.ColumnInt(3),
			Armor:   stmt.ColumnInt(4),
			Level:   stmt.ColumnInt(5),
			MaxExp:  stmt.ColumnInt(6),
			MaxGold: stmt.ColumnInt(7),
			Immune:  stmt.ColumnInt(8),
			db:      db,
		}
		monsters = append(monsters, monster)
		return nil
	})
	
	if err != nil {
		return nil, fmt.Errorf("failed to retrieve all monsters: %w", err)
	}
	
	return monsters, nil
}

// ByLevel retrieves monsters by level
func ByLevel(db *database.DB, level int) ([]*Monster, error) {
	var monsters []*Monster
	
	query := "SELECT id, name, max_hp, max_dmg, armor, level, max_exp, max_gold, immune FROM monsters WHERE level = ? ORDER BY id"
	err := db.Query(query, func(stmt *sqlite.Stmt) error {
		monster := &Monster{
			ID:      stmt.ColumnInt(0),
			Name:    stmt.ColumnText(1),
			MaxHP:   stmt.ColumnInt(2),
			MaxDmg:  stmt.ColumnInt(3),
			Armor:   stmt.ColumnInt(4),
			Level:   stmt.ColumnInt(5),
			MaxExp:  stmt.ColumnInt(6),
			MaxGold: stmt.ColumnInt(7),
			Immune:  stmt.ColumnInt(8),
			db:      db,
		}
		monsters = append(monsters, monster)
		return nil
	}, level)
	
	if err != nil {
		return nil, fmt.Errorf("failed to retrieve monsters by level: %w", err)
	}
	
	return monsters, nil
}

// ByLevelRange retrieves monsters within a level range (inclusive)
func ByLevelRange(db *database.DB, minLevel, maxLevel int) ([]*Monster, error) {
	var monsters []*Monster
	
	query := "SELECT id, name, max_hp, max_dmg, armor, level, max_exp, max_gold, immune FROM monsters WHERE level BETWEEN ? AND ? ORDER BY level, id"
	err := db.Query(query, func(stmt *sqlite.Stmt) error {
		monster := &Monster{
			ID:      stmt.ColumnInt(0),
			Name:    stmt.ColumnText(1),
			MaxHP:   stmt.ColumnInt(2),
			MaxDmg:  stmt.ColumnInt(3),
			Armor:   stmt.ColumnInt(4),
			Level:   stmt.ColumnInt(5),
			MaxExp:  stmt.ColumnInt(6),
			MaxGold: stmt.ColumnInt(7),
			Immune:  stmt.ColumnInt(8),
			db:      db,
		}
		monsters = append(monsters, monster)
		return nil
	}, minLevel, maxLevel)
	
	if err != nil {
		return nil, fmt.Errorf("failed to retrieve monsters by level range: %w", err)
	}
	
	return monsters, nil
}

// ByImmunity retrieves monsters by immunity type
func ByImmunity(db *database.DB, immunityType int) ([]*Monster, error) {
	var monsters []*Monster
	
	query := "SELECT id, name, max_hp, max_dmg, armor, level, max_exp, max_gold, immune FROM monsters WHERE immune = ? ORDER BY level, id"
	err := db.Query(query, func(stmt *sqlite.Stmt) error {
		monster := &Monster{
			ID:      stmt.ColumnInt(0),
			Name:    stmt.ColumnText(1),
			MaxHP:   stmt.ColumnInt(2),
			MaxDmg:  stmt.ColumnInt(3),
			Armor:   stmt.ColumnInt(4),
			Level:   stmt.ColumnInt(5),
			MaxExp:  stmt.ColumnInt(6),
			MaxGold: stmt.ColumnInt(7),
			Immune:  stmt.ColumnInt(8),
			db:      db,
		}
		monsters = append(monsters, monster)
		return nil
	}, immunityType)
	
	if err != nil {
		return nil, fmt.Errorf("failed to retrieve monsters by immunity: %w", err)
	}
	
	return monsters, nil
}

// Builder provides a fluent interface for creating monsters
type Builder struct {
	monster *Monster
	db      *database.DB
}

// NewBuilder creates a new monster builder
func NewBuilder(db *database.DB) *Builder {
	return &Builder{
		monster: &Monster{db: db},
		db:      db,
	}
}

// WithName sets the monster name
func (b *Builder) WithName(name string) *Builder {
	b.monster.Name = name
	return b
}

// WithMaxHP sets the monster's maximum hit points
func (b *Builder) WithMaxHP(maxHP int) *Builder {
	b.monster.MaxHP = maxHP
	return b
}

// WithMaxDmg sets the monster's maximum damage
func (b *Builder) WithMaxDmg(maxDmg int) *Builder {
	b.monster.MaxDmg = maxDmg
	return b
}

// WithArmor sets the monster's armor value
func (b *Builder) WithArmor(armor int) *Builder {
	b.monster.Armor = armor
	return b
}

// WithLevel sets the monster's level
func (b *Builder) WithLevel(level int) *Builder {
	b.monster.Level = level
	return b
}

// WithMaxExp sets the monster's maximum experience reward
func (b *Builder) WithMaxExp(maxExp int) *Builder {
	b.monster.MaxExp = maxExp
	return b
}

// WithMaxGold sets the monster's maximum gold reward
func (b *Builder) WithMaxGold(maxGold int) *Builder {
	b.monster.MaxGold = maxGold
	return b
}

// WithImmunity sets the monster's immunity type
func (b *Builder) WithImmunity(immunity int) *Builder {
	b.monster.Immune = immunity
	return b
}

// Create saves the monster to the database and returns it
func (b *Builder) Create() (*Monster, error) {
	// Use a transaction to ensure we can get the ID
	var monster *Monster
	err := b.db.Transaction(func(tx *database.Tx) error {
		query := `INSERT INTO monsters (name, max_hp, max_dmg, armor, level, max_exp, max_gold, immune) 
		          VALUES (?, ?, ?, ?, ?, ?, ?, ?)`
		
		if err := tx.Exec(query, b.monster.Name, b.monster.MaxHP, b.monster.MaxDmg, b.monster.Armor, 
			b.monster.Level, b.monster.MaxExp, b.monster.MaxGold, b.monster.Immune); err != nil {
			return fmt.Errorf("failed to insert monster: %w", err)
		}
		
		// Get the last inserted ID within the same transaction
		var lastID int
		err := tx.Query("SELECT last_insert_rowid()", func(stmt *sqlite.Stmt) error {
			lastID = stmt.ColumnInt(0)
			return nil
		})
		if err != nil {
			return fmt.Errorf("failed to get last insert ID: %w", err)
		}
		
		// Create the monster with the ID
		monster = &Monster{
			ID:      lastID,
			Name:    b.monster.Name,
			MaxHP:   b.monster.MaxHP,
			MaxDmg:  b.monster.MaxDmg,
			Armor:   b.monster.Armor,
			Level:   b.monster.Level,
			MaxExp:  b.monster.MaxExp,
			MaxGold: b.monster.MaxGold,
			Immune:  b.monster.Immune,
			db:      b.db,
		}
		
		return nil
	})
	
	if err != nil {
		return nil, fmt.Errorf("failed to create monster: %w", err)
	}
	
	return monster, nil
}

// Save updates an existing monster in the database
func (m *Monster) Save() error {
	if m.ID == 0 {
		return fmt.Errorf("cannot save monster without ID")
	}
	
	query := `UPDATE monsters SET name = ?, max_hp = ?, max_dmg = ?, armor = ?, level = ?, max_exp = ?, max_gold = ?, immune = ? WHERE id = ?`
	return m.db.Exec(query, m.Name, m.MaxHP, m.MaxDmg, m.Armor, m.Level, m.MaxExp, m.MaxGold, m.Immune, m.ID)
}

// Delete removes the monster from the database
func (m *Monster) Delete() error {
	if m.ID == 0 {
		return fmt.Errorf("cannot delete monster without ID")
	}
	
	query := "DELETE FROM monsters WHERE id = ?"
	return m.db.Exec(query, m.ID)
}

// IsHurtImmune returns true if the monster is immune to Hurt spells
func (m *Monster) IsHurtImmune() bool {
	return m.Immune == ImmuneHurt
}

// IsSleepImmune returns true if the monster is immune to Sleep spells
func (m *Monster) IsSleepImmune() bool {
	return m.Immune == ImmuneSleep
}

// HasImmunity returns true if the monster has any immunity
func (m *Monster) HasImmunity() bool {
	return m.Immune != ImmuneNone
}

// ImmunityName returns the string representation of the monster's immunity
func (m *Monster) ImmunityName() string {
	switch m.Immune {
	case ImmuneNone:
		return "None"
	case ImmuneHurt:
		return "Hurt Spells"
	case ImmuneSleep:
		return "Sleep Spells"
	default:
		return "Unknown"
	}
}

// DifficultyRating calculates a simple difficulty rating based on stats
func (m *Monster) DifficultyRating() float64 {
	// Simple formula: (HP + Damage + Armor) / Level
	// Higher values indicate tougher monsters relative to their level
	if m.Level == 0 {
		return 0
	}
	return float64(m.MaxHP+m.MaxDmg+m.Armor) / float64(m.Level)
}

// ExpPerHP returns the experience reward per hit point (efficiency metric)
func (m *Monster) ExpPerHP() float64 {
	if m.MaxHP == 0 {
		return 0
	}
	return float64(m.MaxExp) / float64(m.MaxHP)
}

// GoldPerHP returns the gold reward per hit point (efficiency metric)
func (m *Monster) GoldPerHP() float64 {
	if m.MaxHP == 0 {
		return 0
	}
	return float64(m.MaxGold) / float64(m.MaxHP)
}