package chat

import (
	"context"
	"fmt"

	"eq2emu/internal/database"
)

// DatabaseChannelManager implements ChannelDatabase interface using the existing database wrapper
type DatabaseChannelManager struct {
	db *database.DB
}

// NewDatabaseChannelManager creates a new database channel manager
func NewDatabaseChannelManager(db *database.DB) *DatabaseChannelManager {
	return &DatabaseChannelManager{
		db: db,
	}
}

// LoadWorldChannels retrieves all persistent world channels from database
func (dcm *DatabaseChannelManager) LoadWorldChannels(ctx context.Context) ([]ChatChannelData, error) {
	query := "SELECT `name`, `password`, `level_restriction`, `classes`, `races` FROM `channels`"
	
	rows, err := dcm.db.QueryContext(ctx, query)
	if err != nil {
		return nil, fmt.Errorf("failed to query channels: %w", err)
	}
	defer rows.Close()

	var channels []ChatChannelData
	for rows.Next() {
		var channel ChatChannelData
		var password *string

		err := rows.Scan(
			&channel.Name,
			&password,
			&channel.LevelRestriction,
			&channel.ClassRestriction,
			&channel.RaceRestriction,
		)
		if err != nil {
			return nil, fmt.Errorf("failed to scan channel row: %w", err)
		}

		// Handle nullable password field
		if password != nil {
			channel.Password = *password
		}

		channels = append(channels, channel)
	}

	if err := rows.Err(); err != nil {
		return nil, fmt.Errorf("error iterating channel rows: %w", err)
	}

	return channels, nil
}

// SaveChannel persists a channel to database (world channels only)
func (dcm *DatabaseChannelManager) SaveChannel(ctx context.Context, channel ChatChannelData) error {
	// Insert or update channel
	query := `
		INSERT OR REPLACE INTO channels 
		(name, password, level_restriction, classes, races) 
		VALUES (?, ?, ?, ?, ?)`

	var password *string
	if channel.Password != "" {
		password = &channel.Password
	}

	_, err := dcm.db.ExecContext(ctx, query,
		channel.Name,
		password,
		channel.LevelRestriction,
		channel.ClassRestriction,
		channel.RaceRestriction,
	)
	if err != nil {
		return fmt.Errorf("failed to save channel %s: %w", channel.Name, err)
	}

	return nil
}

// DeleteChannel removes a channel from database
func (dcm *DatabaseChannelManager) DeleteChannel(ctx context.Context, channelName string) error {
	query := "DELETE FROM channels WHERE name = ?"
	
	result, err := dcm.db.ExecContext(ctx, query, channelName)
	if err != nil {
		return fmt.Errorf("failed to delete channel %s: %w", channelName, err)
	}

	rowsAffected, err := result.RowsAffected()
	if err != nil {
		return fmt.Errorf("failed to check rows affected for channel %s: %w", channelName, err)
	}

	if rowsAffected == 0 {
		return fmt.Errorf("channel %s not found in database", channelName)
	}

	return nil
}

// EnsureChannelsTable creates the channels table if it doesn't exist
func (dcm *DatabaseChannelManager) EnsureChannelsTable(ctx context.Context) error {
	query := `
		CREATE TABLE IF NOT EXISTS channels (
			name TEXT PRIMARY KEY,
			password TEXT,
			level_restriction INTEGER NOT NULL DEFAULT 0,
			classes INTEGER NOT NULL DEFAULT 0,
			races INTEGER NOT NULL DEFAULT 0,
			created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
			updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
		)`

	_, err := dcm.db.ExecContext(ctx, query)
	if err != nil {
		return fmt.Errorf("failed to create channels table: %w", err)
	}

	return nil
}

// GetChannelCount returns the total number of channels in the database
func (dcm *DatabaseChannelManager) GetChannelCount(ctx context.Context) (int, error) {
	query := "SELECT COUNT(*) FROM channels"
	
	var count int
	err := dcm.db.QueryRowContext(ctx, query).Scan(&count)
	if err != nil {
		return 0, fmt.Errorf("failed to get channel count: %w", err)
	}

	return count, nil
}

// GetChannelByName retrieves a specific channel by name
func (dcm *DatabaseChannelManager) GetChannelByName(ctx context.Context, channelName string) (*ChatChannelData, error) {
	query := "SELECT `name`, `password`, `level_restriction`, `classes`, `races` FROM `channels` WHERE `name` = ?"
	
	var channel ChatChannelData
	var password *string

	err := dcm.db.QueryRowContext(ctx, query, channelName).Scan(
		&channel.Name,
		&password,
		&channel.LevelRestriction,
		&channel.ClassRestriction,
		&channel.RaceRestriction,
	)
	if err != nil {
		return nil, fmt.Errorf("failed to get channel %s: %w", channelName, err)
	}

	// Handle nullable password field
	if password != nil {
		channel.Password = *password
	}

	return &channel, nil
}

// ListChannelNames returns a list of all channel names in the database
func (dcm *DatabaseChannelManager) ListChannelNames(ctx context.Context) ([]string, error) {
	query := "SELECT name FROM channels ORDER BY name"
	
	rows, err := dcm.db.QueryContext(ctx, query)
	if err != nil {
		return nil, fmt.Errorf("failed to query channel names: %w", err)
	}
	defer rows.Close()

	var names []string
	for rows.Next() {
		var name string
		if err := rows.Scan(&name); err != nil {
			return nil, fmt.Errorf("failed to scan channel name: %w", err)
		}
		names = append(names, name)
	}

	if err := rows.Err(); err != nil {
		return nil, fmt.Errorf("error iterating channel name rows: %w", err)
	}

	return names, nil
}

// UpdateChannelPassword updates just the password for a channel
func (dcm *DatabaseChannelManager) UpdateChannelPassword(ctx context.Context, channelName, password string) error {
	query := "UPDATE channels SET password = ?, updated_at = CURRENT_TIMESTAMP WHERE name = ?"
	
	var passwordParam *string
	if password != "" {
		passwordParam = &password
	}

	result, err := dcm.db.ExecContext(ctx, query, passwordParam, channelName)
	if err != nil {
		return fmt.Errorf("failed to update password for channel %s: %w", channelName, err)
	}

	rowsAffected, err := result.RowsAffected()
	if err != nil {
		return fmt.Errorf("failed to check rows affected for channel %s: %w", channelName, err)
	}

	if rowsAffected == 0 {
		return fmt.Errorf("channel %s not found in database", channelName)
	}

	return nil
}

// UpdateChannelRestrictions updates the level, race, and class restrictions for a channel
func (dcm *DatabaseChannelManager) UpdateChannelRestrictions(ctx context.Context, channelName string, levelRestriction, classRestriction, raceRestriction int32) error {
	query := "UPDATE channels SET level_restriction = ?, classes = ?, races = ?, updated_at = CURRENT_TIMESTAMP WHERE name = ?"
	
	result, err := dcm.db.ExecContext(ctx, query, levelRestriction, classRestriction, raceRestriction, channelName)
	if err != nil {
		return fmt.Errorf("failed to update restrictions for channel %s: %w", channelName, err)
	}

	rowsAffected, err := result.RowsAffected()
	if err != nil {
		return fmt.Errorf("failed to check rows affected for channel %s: %w", channelName, err)
	}

	if rowsAffected == 0 {
		return fmt.Errorf("channel %s not found in database", channelName)
	}

	return nil
}