package services

import (
	"context"
	"time"

	"github.com/nutcas3/telecom-platform/apps/api-server/internal/config"
	"github.com/nutcas3/telecom-platform/apps/api-server/internal/database"
	"github.com/nutcas3/telecom-platform/apps/api-server/internal/models"
)

// ChargingService handles charging and billing operations
type ChargingService struct {
	db     *database.Database
	engine *ChargingEngineClient
}

// NewChargingService creates a new charging service
func NewChargingService(db *database.Database, cfg *config.Config) *ChargingService {
	return &ChargingService{
		db:     db,
		engine: NewChargingEngineClient(&cfg.ChargingEngine),
	}
}

// GetSystemStats gets system statistics
func (cs *ChargingService) GetSystemStats(ctx context.Context) (*models.SystemStats, error) {
	// This would get actual system stats in a real implementation
	// For now, return placeholder data
	stats := &models.SystemStats{
		ActiveSessions:   10,
		TotalAccounts:    100,
		BlockedUsers:     5,
		LowBalanceAlerts: 3,
		Uptime:           86400.0, // 1 day in seconds
	}
	return stats, nil
}

// GetHealthStatus gets health status
func (cs *ChargingService) GetHealthStatus(ctx context.Context) (*models.HealthStatus, error) {
	// This would get actual health status in a real implementation
	// For now, return placeholder data
	status := &models.HealthStatus{
		RedisConnected: true,
		ActiveSync:     true,
		LastSync:       time.Now(),
		MemoryUsage:    50000000, // 50MB
	}
	return status, nil
}

// GetUsageStats gets usage statistics for a subscriber
func (cs *ChargingService) GetUsageStats(ctx context.Context, imsi string, period string) (*UsageStats, error) {
	// This would get actual usage stats in a real implementation
	// For now, return placeholder data
	stats := &UsageStats{
		DataUsage:  1000000000, // 1GB
		VoiceUsage: 300,        // 300 minutes
		SmsUsage:   50,         // 50 SMS
		Cost:       25.50,      // $25.50
		Period:     period,
		Trend: &UsageTrend{
			Direction:        "UP",
			Percentage:       15.5,
			PeriodOverPeriod: 12.3,
		},
	}
	return stats, nil
}

// GetRealTimeUsage gets real-time usage for a subscriber
func (cs *ChargingService) GetRealTimeUsage(ctx context.Context, imsi string) (*RealTimeUsage, error) {
	// This would get actual real-time usage in a real implementation
	// For now, return placeholder data
	usage := &RealTimeUsage{
		CurrentSession: &CurrentSession{
			SessionID: "session_123",
			StartTime: time.Now().Add(-1 * time.Hour),
			DataUsed:  100000000, // 100MB
			VoiceUsed: 10,        // 10 minutes
			SmsUsed:   2,         // 2 SMS
			Cost:      1.25,      // $1.25
		},
		TodayUsage: &TodayUsage{
			DataUsed:  500000000, // 500MB
			VoiceUsed: 45,        // 45 minutes
			SmsUsed:   8,         // 8 SMS
			Cost:      5.75,      // $5.75
		},
	}
	return usage, nil
}

// ListUsageEvents lists usage events
func (cs *ChargingService) ListUsageEvents(ctx context.Context, limit int, offset int, where string) ([]*models.UsageEvent, int64, error) {
	// This would get actual usage events in a real implementation
	// For now, return placeholder data
	events := []*models.UsageEvent{
		{
			ID:        1,
			IMSI:      "123456789012345",
			SessionID: "session_123",
			UsageType: models.UsageTypeData,
			Volume:    100000000, // 100MB
			Timestamp: time.Now().Add(-1 * time.Hour),
			Rate:      0.01,
			Cost:      1.00,
		},
	}
	return events, int64(len(events)), nil
}

// SearchUsageEvents searches usage events
func (cs *ChargingService) SearchUsageEvents(ctx context.Context, query string, limit int) ([]*models.UsageEvent, error) {
	// This would search actual usage events in a real implementation
	// For now, return placeholder data
	events := []*models.UsageEvent{
		{
			ID:        1,
			IMSI:      "123456789012345",
			SessionID: "session_123",
			UsageType: models.UsageTypeData,
			Volume:    100000000, // 100MB
			Timestamp: time.Now().Add(-1 * time.Hour),
			Rate:      0.01,
			Cost:      1.00,
		},
	}
	return events, nil
}

// SubscribeToUsageUpdates subscribes to usage updates
func (cs *ChargingService) SubscribeToUsageUpdates(ctx context.Context, imsi string) (<-chan *models.UsageEvent, error) {
	// This would set up actual subscription in a real implementation
	// For now, return a closed channel
	ch := make(chan *models.UsageEvent)
	close(ch)
	return ch, nil
}

// SubscribeToSystemStatsUpdates subscribes to system stats updates
func (cs *ChargingService) SubscribeToSystemStatsUpdates(ctx context.Context) (<-chan *models.SystemStats, error) {
	// This would set up actual subscription in a real implementation
	// For now, return a closed channel
	ch := make(chan *models.SystemStats)
	close(ch)
	return ch, nil
}

// TriggerMaintenance triggers system maintenance
func (cs *ChargingService) TriggerMaintenance(ctx context.Context) (bool, error) {
	// This would trigger actual maintenance in a real implementation
	// For now, return success
	return true, nil
}

// Helper types for charging service
type UsageStats struct {
	DataUsage  float64     `json:"data_usage"`
	VoiceUsage float64     `json:"voice_usage"`
	SmsUsage   float64     `json:"sms_usage"`
	Cost       float64     `json:"cost"`
	Period     string      `json:"period"`
	Trend      *UsageTrend `json:"trend"`
}

type UsageTrend struct {
	Direction        string  `json:"direction"`
	Percentage       float64 `json:"percentage"`
	PeriodOverPeriod float64 `json:"period_over_period"`
}

type RealTimeUsage struct {
	CurrentSession *CurrentSession `json:"current_session"`
	TodayUsage     *TodayUsage     `json:"today_usage"`
}

type CurrentSession struct {
	SessionID string    `json:"session_id"`
	StartTime time.Time `json:"start_time"`
	DataUsed  float64   `json:"data_used"`
	VoiceUsed float64   `json:"voice_used"`
	SmsUsed   float64   `json:"sms_used"`
	Cost      float64   `json:"cost"`
}

type TodayUsage struct {
	DataUsed  float64 `json:"data_used"`
	VoiceUsed float64 `json:"voice_used"`
	SmsUsed   float64 `json:"sms_used"`
	Cost      float64 `json:"cost"`
}