package app

import (
	"sync"
)

const (
	ChunkSize = 16
)

// Point represents the request body for setting cell position
type Point struct {
	X, Y int
}

// Area represents the visible area for SSE updates
type Area struct {
	X, Y, Width, Height int
}

// Contains checks if a point is within the SSE area
func (a Area) Contains(x int, y int) bool {
	return x >= a.X && x <= a.X+a.Width && y >= a.Y && y <= a.Y+a.Height
}

// SpatialHashMap implements spatial hashing for efficient point storage and retrieval
type SpatialHashMap struct {
	mu sync.RWMutex
	db *SQLiteEngine
}

// NewSpatialHashMap creates a new spatial hash map
func NewSpatialHashMap(dbPath string) (*SpatialHashMap, error) {
	db, err := CreateSQLite(dbPath)
	if err != nil {
		return nil, err
	}
	return &SpatialHashMap{
		db: db,
	}, nil
}

func (s *SpatialHashMap) InitSchema() error {
	err := s.db.Execute(
		`CREATE TABLE IF NOT EXISTS spatial_hashmap (
			cluster_x INTEGER NOT NULL,
			cluster_y INTEGER NOT NULL,
			x INTEGER NOT NULL,
			y INTEGER NOT NULL,
			PRIMARY KEY (cluster_x, cluster_y, x, y)) WITHOUT ROWID`)
	if err != nil {
		return err
	}
	return nil
}

// getHash calculates the hash coordinates for a given point
func (s *SpatialHashMap) getHash(x, y int) Point {
	return Point{X: x / ChunkSize, Y: y / ChunkSize}
}

// Insert adds a point to the spatial hash map
func (s *SpatialHashMap) Insert(x, y int) error {
	s.mu.Lock()
	defer s.mu.Unlock()

	key := s.getHash(x, y)
	err := s.db.Execute(
		"INSERT INTO spatial_hashmap (cluster_x, cluster_y, x, y) VALUES (?, ?, ?, ?)",
		key.X, key.Y, x, y)
	if err != nil {
		return err

	}
	return nil
}

// Remove removes a point from the spatial hash map
func (s *SpatialHashMap) Remove(x, y int) error {
	s.mu.Lock()
	defer s.mu.Unlock()

	key := s.getHash(x, y)
	err := s.db.Execute(
		"DELETE FROM spatial_hashmap WHERE cluster_x = ? AND cluster_y = ? AND x = ? AND y = ?",
		key.X, key.Y, x, y)
	if err != nil {
		return err
	}
	return nil
}

// GetLocalPoints returns all points within the given bounding box
func (s *SpatialHashMap) GetLocalPoints(area Area) []Point {
	hashStart, hashEnd := s.getHash(area.X, area.Y), s.getHash(area.X+area.Width, area.Y+area.Height)

	rows, err := s.db.Query(
		"SELECT x, y FROM spatial_hashmap WHERE cluster_x BETWEEN ? AND ? AND cluster_y BETWEEN ? AND ?",
		hashStart.X, hashEnd.X, hashStart.Y, hashEnd.Y)
	if err != nil {
		return nil
	}
	defer rows.Close()

	localPoints := make([]Point, 0)
	for rows.Next() {
		var x, y int
		if err := rows.Scan(&x, &y); err != nil {
			continue
		}
		localPoints = append(localPoints, Point{X: x, Y: y})
	}
	return localPoints
}

func (s *SpatialHashMap) Close() error {
	if s.db != nil {
		return s.db.Close()
	}
	return nil
}