package database

import (
	"database/sql"
	"time"

	"github.com/rs/zerolog"

	"base/pkg/metrics"
)

// monitorConnectionPool periodically monitors and records connection pool metrics
func monitorConnectionPool(sqlDB *sql.DB, metric *metrics.Metrics, logger zerolog.Logger) {
	ticker := time.NewTicker(30 * time.Second) // Monitor every 30 seconds
	defer ticker.Stop()

	for range ticker.C {
		stats := sqlDB.Stats()

		// Record connection pool metrics using available methods
		// Note: Connection pool size metrics are not available in current metrics package
		// Consider adding them if needed for monitoring

		// Record wait time if there are any waits
		if stats.WaitCount > 0 {
			avgWaitTime := time.Duration(stats.WaitDuration.Nanoseconds() / stats.WaitCount)
			metric.RecordDatabaseQuery("WaitTime", "database", avgWaitTime, nil)
		}

		// Log connection pool stats at info level for better visibility
		logger.Info().
			Int("open_connections", stats.OpenConnections).
			Int("in_use", stats.InUse).
			Int("idle", stats.Idle).
			Int("max_open", stats.MaxOpenConnections).
			Int64("wait_count", stats.WaitCount).
			Int64("wait_duration_ms", stats.WaitDuration.Milliseconds()).
			Msg("Database connection pool stats")

		// Alert if we're approaching connection limits
		if stats.OpenConnections >= 7 { // 7 out of 8 max connections
			logger.Warn().
				Int("open_connections", stats.OpenConnections).
				Int("max_open", stats.MaxOpenConnections).
				Msg("Database connection pool approaching limit - consider reducing concurrent operations")
		}

		// Alert if there are connection waits
		if stats.WaitCount > 0 {
			logger.Warn().
				Int64("wait_count", stats.WaitCount).
				Int64("wait_duration_ms", stats.WaitDuration.Milliseconds()).
				Msg("Database connections are being waited for - possible connection pool exhaustion")
		}
	}
}