package contract

import (
	"context"
	"errors"
	"fmt"
	"log"
	"net/http"
	"strings"
	"time"

	"github.com/jinzhu/gorm"
	"github.com/lib/pq"
	"gitlab.com/pactual1/backend/config"
	"gitlab.com/pactual1/backend/database/device"
	"gitlab.com/pactual1/backend/models"
	"gitlab.com/pactual1/backend/services/blockchain"
	"gitlab.com/pactual1/backend/services/messaging"
	"gitlab.com/pactual1/backend/shared"
)

func GetContracts(status []string, companyName string, companyAddress string,
	companyEmail string, companyPhone string, startTime *time.Time, endTime *time.Time,
	contractName string, deviceIDs []int64, contractIDs []int64, dateCreated *time.Time, limit, offset int) ([]models.Contract, int64, int, error) {

	var contracts []models.Contract
	db := shared.GetDb()
	countDb := db

	customFields := "distinct contracts.*, array_length(contracts.device_ids, 1) as number_of_devices, " +
		"(SELECT array_agg(devices.imei) FROM devices WHERE devices.id = ANY(contracts.device_ids)) as devices_imeis_scanner"

	// Search by Statuses
	if len(status) > 0 {
		db = db.Where("contracts.status IN (?)", status)
		countDb = countDb.Where("contracts.status IN (?)", status)
	}

	// Search by IDs
	if len(contractIDs) > 0 {
		db = db.Where("contracts.id IN (?)", contractIDs)
		countDb = countDb.Where("contracts.id IN (?)", contractIDs)
	}

	// Search by Company Fields
	db = db.Joins("left join companies on companies.id = contracts.buyer_id")
	countDb = countDb.Joins("left join companies on companies.id = contracts.buyer_id")
	customFields += ", companies.name as buyer_name"
	if companyName != "" {
		db = db.Where("companies.name LIKE ?", "%"+companyName+"%")
		countDb = countDb.Where("companies.name LIKE ?", "%"+companyName+"%")
	}
	if companyAddress != "" {
		db = db.Where("companies.address LIKE ?", "%"+companyAddress+"%")
		countDb = countDb.Where("companies.address LIKE ?", "%"+companyAddress+"%")
	}
	if companyEmail != "" {
		db = db.Where("companies.email LIKE ?", "%"+companyEmail+"%")
		countDb = countDb.Where("companies.email LIKE ?", "%"+companyEmail+"%")
	}
	if companyPhone != "" {
		db = db.Where("companies.phone LIKE ?", "%"+companyPhone+"%")
		countDb = countDb.Where("companies.phone LIKE ?", "%"+companyPhone+"%")
	}

	// Search by Contract Name
	if contractName != "" {
		db = db.Where("lower(contracts.name) LIKE ?", "%"+strings.ToLower(contractName)+"%")
		countDb = countDb.Where("lower(contracts.name) LIKE ?", "%"+strings.ToLower(contractName)+"%")
	}

	// Search by Start Time and End Time
	if startTime != nil && !startTime.IsZero() {
		db = db.Where("start_time >= ?", startTime)
		countDb = countDb.Where("start_time >= ?", startTime)
	}

	if endTime != nil && !startTime.IsZero() {
		db = db.Where("end_time <= ?", endTime)
		countDb = countDb.Where("end_time <= ?", endTime)
	}

	if dateCreated != nil && !dateCreated.IsZero() {
		db = db.Where("contracts.created_at = ?", dateCreated)
		countDb = countDb.Where("contracts.created_at = ?", dateCreated)
	}

	// Search by Device IDs
	if len(deviceIDs) > 0 {
		db = db.Where("contracts.device_ids && ?", pq.Array(deviceIDs))
		countDb = countDb.Where("contracts.device_ids && ?", pq.Array(deviceIDs))
	}

	// Fetch total count of filtered records
	var total int64
	if err := countDb.Model(&models.Contract{}).Count(&total).Error; err != nil {
		log.Printf("GetContracts Error: Database error: %v", err)
		return contracts, total, http.StatusInternalServerError, err
	}

	// Fetch contracts with custom fields
	if err := db.Select(customFields).
		Order("created_at desc").
		Limit(limit).
		Offset(offset).
		Find(&contracts).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			log.Printf("GetContracts Error: No contracts found: %v", err)
			return contracts, total, http.StatusNotFound, err
		} else {
			log.Printf("GetContracts Error: Database error: %v", err)
			return contracts, total, http.StatusInternalServerError, err
		}
	}
	for i := range contracts {
		contracts[i].DevicesImeis = []string(contracts[i].DevicesImeisScanner)
		// Now DevicesImeis contains the IMEIs, and you can use them as needed
	}

	return contracts, total, http.StatusOK, nil
}

func UpdateContract(contract models.Contract) (models.Contract, int, error) {
	var devices []models.Device
	var status int
	var err error
	if contract.DevicesImeis != nil {
		log.Printf("Found devices imes %v", contract.DevicesImeis)
		devices, status, err = device.GetDevicesByImei(contract.DevicesImeis)
		if err != nil {
			return contract, status, err
		}

		status, err = validateContractDevices(contract.ID, devices)
		if err != nil {
			log.Printf("UpdateContract Error: Invalid Device ID: %v", err)
			return contract, status, err
		}
	}

	// get old contract to compare updates
	oldContract, status, err := GetContractByID(contract.ID)
	if err != nil {
		return contract, status, err
	}

	err = shared.GetDb().Transaction(func(tx *gorm.DB) error {
		// Update contract
		if err := tx.Model(contract).Updates(contract).Error; err != nil {
			log.Printf("UpdateContract Error: Could not update contract: %v", err)
			return err
		}

		if devices != nil {
			// Update devices
			if err := tx.Model(models.Device{}).Where("id IN (?)", []int64(contract.DeviceIDs)).Updates(models.Device{CurrentContractID: &contract.ID}).Error; err != nil {
				log.Printf("UpdateContract Error: Could not update devices: %v", err)
				return err
			}
		}

		// return nil will commit the whole transaction
		return nil
	})
	if err != nil {
		log.Printf("UpdateContract Error: Could not update contract: %v", err)
		return contract, http.StatusInternalServerError, err
	}

	contract, status, err = GetContractByID(contract.ID)
	if err != nil {
		return contract, status, err
	}

	// Create contract in blockchain only when it is signed
	if oldContract.Status != contract.Status {

		if contract.Status == models.ContractStatusSigned {
			err = blockchain.NewService(config.AppConfig.Blockchain).CreateContract(context.Background(), shared.CovertUintToByte32(contract.ID))
			if err != nil {
				log.Printf("UpdateContract Error: Could not create contract in blockchain: %v", err)
				return contract, http.StatusInternalServerError, err
			}

			// Register devices in blockchain when contract is signed
			for _, device := range devices {
				err = blockchain.NewService(config.AppConfig.Blockchain).RegisterNewDeviceID(context.Background(), shared.CovertUintToByte32(contract.ID), shared.CovertUintToByte32(device.ID))
				if err != nil {
					log.Printf("UpdateContract Error: Could not register contract device in blockchain: %v", err)
					return contract, http.StatusInternalServerError, err
				}
			}
		}

		messagingChannel := messaging.GetMessagingChannel()

		notification := models.Notification{
			Title:            "Contract Alert",
			NotificationType: "Contract",
			Text:             fmt.Sprintf("Contract %s status updated to %s", contract.Name, contract.Status),
			CompanyID:        int(contract.BuyerID),
		}
		messagingChannel <- notification

		sellerNotification := models.Notification{
			Title:            "Contract Alert",
			NotificationType: "Contract",
			Text:             fmt.Sprintf("Contract %s status updated to %s", contract.Name, contract.Status),
			CompanyID:        int(contract.SellerID),
		}
		messagingChannel <- sellerNotification
	}

	return contract, status, err
}

func validateContractDevices(contractID uint, devices []models.Device) (int, error) {

	for _, device := range devices {
		if device.CurrentContractID != nil && *device.CurrentContractID != contractID {
			currentDeviceContract, status, err := GetContractByID(*device.CurrentContractID)
			if err != nil {
				return status, err
			}

			if currentDeviceContract.Status != models.ContractStatusExecuted &&
				currentDeviceContract.Status == models.ContractStatusRevoked {
				return http.StatusBadRequest, fmt.Errorf("device id %d is linked to contract id - %d name %s", device.ID, currentDeviceContract.ID, currentDeviceContract.Name)
			}
		}
	}

	return http.StatusOK, nil
}

func GetContractByID(contractID uint) (models.Contract, int, error) {

	// Fetch the contract creation date based on contractID
	var contract models.Contract
	if err := shared.GetDb().Unscoped().Where("id = ?", contractID).First(&contract).Error; err != nil {
		log.Printf("GetContractByID Error: Could not fetch contract: %v", err)
		return contract, http.StatusInternalServerError, err
	}

	// Fetch the product
	var product models.ProductTemplate
	if err := shared.GetDb().Unscoped().Where("id = ?", contract.ProductID).First(&product).Error; err != nil {
		log.Printf("GetContractByID Error: Could not fetch product: %v", err)
		return contract, http.StatusInternalServerError, err
	}
	contract.ProductName = product.Name

	// Fetch the seller
	var seller models.Company
	if err := shared.GetDb().Unscoped().Where("id = ?", contract.SellerID).First(&seller).Error; err != nil {
		log.Printf("GetContractByID Error: Could not fetch seller: %v", err)
		return contract, http.StatusInternalServerError, err
	}
	contract.SellerName = seller.Name

	// Fetch the buyer
	var buyer models.Company
	if err := shared.GetDb().Unscoped().Where("id = ?", contract.BuyerID).First(&buyer).Error; err != nil {
		log.Printf("GetContractByID Error: Could not fetch buyer: %v", err)
		return contract, http.StatusInternalServerError, err
	}
	contract.BuyerName = buyer.Name

	// Fetch the devices
	// Convert DeviceIDs from pq.Int64Array to []int64 for the query
	deviceIDs := make([]int64, 0, len(contract.DeviceIDs))
	for _, id := range contract.DeviceIDs {
		deviceIDs = append(deviceIDs, int64(id))
	}

	// Fetch the devices using the slice of device IDs
	var devicesInfo []models.ContractDeviceInfo
	if err := shared.GetDb().
		Table("devices"). // Specify the actual table name for devices
		Where("id IN (?)", deviceIDs).
		Select("id, imei").
		Find(&devicesInfo).Error; err != nil {
		log.Printf("GetContractByID Error: Could not fetch devices: %v", err)
		return contract, http.StatusInternalServerError, err
	}

	// Prepare a slice of IMEIs to add to the contract
	deviceImeis := make([]string, len(devicesInfo))
	for i, device := range devicesInfo {
		deviceImeis[i] = device.IMEI
	}

	contract.DevicesImeis = deviceImeis

	return contract, http.StatusOK, nil
}

func CountContractsByMultipleStatusesAndTotal(companyID uint, startTime, endTime time.Time) (int64, int64, int64, map[string]map[string]int64, error) {
	var activeCount, executedCount, totalCount int64
	monthlyCounts := make(map[string]map[string]int64)

	var contract models.Contract

	// Iterate through each month within the specified date range
	for dt := startTime; dt.Before(endTime); dt = dt.AddDate(0, 1, 0) {
		monthEnd := dt.AddDate(0, 1, 0)
		if monthEnd.After(endTime) {
			monthEnd = endTime
		}

		// Initialize monthlyCounts for the current month
		monthKey := dt.Format("2006-01")
		monthlyCounts[monthKey] = map[string]int64{"active": 0, "executed": 0, "total": 0}

		// Query for 'active' contracts for the current month
		var active int64
		err := shared.GetDb().Model(&contract).
			Where("status = ? AND (buyer_id = ? OR seller_id = ?) AND start_time >= ? AND end_time <= ?", "active", companyID, companyID, dt, monthEnd).
			Count(&active).Error
		if err != nil {
			return 0, 0, 0, nil, err
		}

		// Query for 'executed' contracts for the current month
		var executed int64
		err = shared.GetDb().Model(&contract).
			Where("status = ? AND (buyer_id = ? OR seller_id = ?) AND start_time >= ? AND end_time <= ?", "executed", companyID, companyID, dt, monthEnd).
			Count(&executed).Error
		if err != nil {
			return 0, 0, 0, nil, err
		}

		// Query for total contracts for the current month
		var total int64
		err = shared.GetDb().Model(&contract).
			Where("(buyer_id = ? OR seller_id = ?) AND start_time >= ? AND end_time <= ?", companyID, companyID, dt, monthEnd).
			Count(&total).Error
		if err != nil {
			return 0, 0, 0, nil, err
		}

		// Update the counts for the current month
		monthlyCounts[monthKey]["active"] = active
		monthlyCounts[monthKey]["executed"] = executed
		monthlyCounts[monthKey]["total"] = total

		// Update the total counts
		activeCount += active
		executedCount += executed
		totalCount += total
	}

	return activeCount, executedCount, totalCount, monthlyCounts, nil
}