package db

import (
	"time"
)

// Event represents an event row in the database.
type Event struct {
	ID        int64     `json:"id"`
	SessionID string    `json:"session_id"`
	EventName string    `json:"event_name"`
	ToolName  string    `json:"tool_name,omitempty"`
	Payload   string    `json:"payload"`
	CreatedAt time.Time `json:"created_at"`
}

// InsertEvent inserts a new event.
func (db *DB) InsertEvent(sessionID, eventName, toolName, payload string) (int64, error) {
	result, err := db.Exec(`
		INSERT INTO events (session_id, event_name, tool_name, payload)
		VALUES (?, ?, ?, ?)
	`, sessionID, eventName, toolName, payload)
	if err != nil {
		return 0, err
	}
	return result.LastInsertId()
}

// ListEvents returns events for a session, with optional pagination.
func (db *DB) ListEvents(sessionID string, limit, offset int) ([]*Event, error) {
	if limit <= 0 {
		limit = 100
	}

	rows, err := db.Query(`
		SELECT id, session_id, event_name, tool_name, payload, created_at
		FROM events
		WHERE session_id = ?
		ORDER BY id DESC
		LIMIT ? OFFSET ?
	`, sessionID, limit, offset)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var events []*Event
	for rows.Next() {
		e := &Event{}
		if err := rows.Scan(&e.ID, &e.SessionID, &e.EventName, &e.ToolName, &e.Payload, &e.CreatedAt); err != nil {
			return nil, err
		}
		events = append(events, e)
	}
	return events, nil
}

// CountEvents returns the total number of events for a session.
func (db *DB) CountEvents(sessionID string) (int, error) {
	var count int
	err := db.QueryRow("SELECT COUNT(*) FROM events WHERE session_id = ?", sessionID).Scan(&count)
	return count, err
}