package db

import (
	"context"
	"time"

	"github.com/jackc/pgx/v5"
)

// Workstation represents a registered client machine.
type Workstation struct {
	ID        string
	Name      string
	UserID    string
	Hostname  string
	LastSeen  time.Time
	CreatedAt time.Time
}

// WorkstationRepository provides workstation database operations.
type WorkstationRepository struct {
	db *DB
}

// NewWorkstationRepository creates a new workstation repository.
func NewWorkstationRepository(db *DB) *WorkstationRepository {
	return &WorkstationRepository{db: db}
}

// Upsert registers a workstation, updating hostname and last_seen if it already exists.
func (r *WorkstationRepository) Upsert(ctx context.Context, w *Workstation) error {
	return r.db.pool.QueryRow(ctx, `
		INSERT INTO workstations (name, user_id, hostname)
		VALUES ($1, $2, $3)
		ON CONFLICT (user_id, name) DO UPDATE
			SET hostname = EXCLUDED.hostname, last_seen = now()
		RETURNING id, last_seen, created_at
	`, w.Name, w.UserID, w.Hostname).Scan(&w.ID, &w.LastSeen, &w.CreatedAt)
}

// GetByID returns a workstation by its ID.
func (r *WorkstationRepository) GetByID(ctx context.Context, id string) (*Workstation, error) {
	w := &Workstation{}
	err := r.db.pool.QueryRow(ctx, `
		SELECT id, name, user_id, hostname, last_seen, created_at
		FROM workstations
		WHERE id = $1
	`, id).Scan(&w.ID, &w.Name, &w.UserID, &w.Hostname, &w.LastSeen, &w.CreatedAt)

	if err == pgx.ErrNoRows {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}
	return w, nil
}

// ListByUser returns all workstations for a user.
func (r *WorkstationRepository) ListByUser(ctx context.Context, userID string) ([]*Workstation, error) {
	rows, err := r.db.pool.Query(ctx, `
		SELECT id, name, user_id, hostname, last_seen, created_at
		FROM workstations
		WHERE user_id = $1
		ORDER BY name
	`, userID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var workstations []*Workstation
	for rows.Next() {
		w := &Workstation{}
		if err := rows.Scan(&w.ID, &w.Name, &w.UserID, &w.Hostname, &w.LastSeen, &w.CreatedAt); err != nil {
			return nil, err
		}
		workstations = append(workstations, w)
	}
	return workstations, rows.Err()
}

// Touch updates a workstation's last_seen timestamp.
func (r *WorkstationRepository) Touch(ctx context.Context, id string) error {
	_, err := r.db.pool.Exec(ctx, `
		UPDATE workstations SET last_seen = now() WHERE id = $1
	`, id)
	return err
}

// Delete removes a workstation.
func (r *WorkstationRepository) Delete(ctx context.Context, id string) error {
	_, err := r.db.pool.Exec(ctx, `DELETE FROM workstations WHERE id = $1`, id)
	return err
}