public class LeadClass implements Database.Batchable<SObject> {

    // Start method for the batch job
    public Database.QueryLocator start(Database.BatchableContext context) {
        // Calculate the datetime four hours ago
        DateTime fourHoursAgo = DateTime.now().addHours(-4);

        // Retrieve the leads that meet the criteria
        return Database.getQueryLocator([
            SELECT Id, OwnerId, Owner.Email, Owner.Type, CreatedDate
            FROM Lead
            WHERE Status = 'Open - Not Contacted' AND CreatedDate >= :fourHoursAgo
        ]);
    }

    // Execute method for processing the batch
    public void execute(Database.BatchableContext context, List<Lead> scope) {
        // Create a map to store email messages
        Map<Id, Messaging.SingleEmailMessage> emailMap = new Map<Id, Messaging.SingleEmailMessage>();

        // Create a set to store owner IDs
        Set<Id> ownerIds = new Set<Id>();

        // Create a set to store queue IDs
        Set<Id> queueIds = new Set<Id>();

        // Create a map to store List of Owner for every lead
        Map<Id, List<Id>> idLeadidUsersMap = new Map<Id, List<Id>>();
        
        // Iterate over the leads in the current batch
        for (Lead lead : scope) {
            if (lead.Owner.Type == 'User') {
                // Add the lead's owner ID to the set of owner IDs
                ownerIds.add(lead.OwnerId);
                idLeadidUsersMap.put(lead.Id, new List<Id>{lead.OwnerId});
            } else if (lead.Owner.Type == 'Queue') {
                // Add the lead's owner ID to the set of queue IDs
                queueIds.add(lead.OwnerId);
            }
        }
        
        // create map to store list of Queue users by Queue Id
        Map<Id, List<Id>> idMap = new Map<Id, List<Id>>();
        
        // create map of Group Member of the Queue Id 
        Map<Id, GroupMember> memberMap = new Map<Id, GroupMember>([SELECT UserOrGroupId, GroupId FROM GroupMember WHERE GroupId = :queueIds]);
        
        // iterate over Group Member to create Map list of Users in Queue
		for(GroupMember member : memberMap.values())
        {
            ownerIds.add(member.UserOrGroupId);
            List<Id> tempList = new List<Id>{member.UserOrGroupId};
            if(idMap.containsKey(member.GroupId))
            {
                tempList = idMap.get(member.GroupId);
                tempList.add(member.UserOrGroupId);
            }
            idMap.put(member.GroupId, tempList);
        }
        
		// iterate over lead records collect list of users per lead
        for (Lead lead : scope) {            
            if(lead.Owner.Type == 'Queue' && idMap != null && idMap.get(lead.OwnerId) != null) {               
                idLeadidUsersMap.put(lead.Id, idMap.get(lead.OwnerId));
            }
        }
        
        // Query the owners and their details using the owner IDs
        Map<Id, User> ownerMap = new Map<Id, User>([
            SELECT Id, Name, Email, ManagerId
            FROM User
            WHERE Id IN :ownerIds
        ]);

        // Create a set to store manager IDs
        Set<Id> managerIds = new Set<Id>();

        // Iterate over the owner records to collect manager IDs
        for (User owner : ownerMap.values()) {
            system.debug('User : ' + owner.ManagerId);
            if (owner.ManagerId != null) {
                // Add the owner's manager ID to the set of manager IDs
                managerIds.add(owner.ManagerId);
            }
        }

        // Query the managers and their details using the manager IDs
        Map<Id, User> managerMap = new Map<Id, User>([
            SELECT Id, Name, Email
            FROM User
            WHERE Id IN :managerIds
        ]);
        
        
        for(Lead lead : scope)
        {    
            for(Id iduser : idLeadidUsersMap.get(lead.Id))
            {
                
                // Retrieve the lead's owner from the ownerMap                
                User owner = ownerMap.get(idUser);
                system.debug('lead Id : ' + lead.Id + ' --  owner : ' + owner.Id + ' -- Manage : ' + owner.ManagerId);                
                // Create an email message
                Messaging.SingleEmailMessage email = new Messaging.SingleEmailMessage();

                // Set the recipient (owner's email address)
                email.setToAddresses(new List<String>{ owner.Email });

                // Add owner's manager's email to cc recipients if available
                if (owner.ManagerId != null && managerMap.containsKey(owner.ManagerId)) {
                    User manager = managerMap.get(owner.ManagerId);
                    if (manager != null && !String.isBlank(manager.Email)) {
                        email.setCcAddresses(new List<String>{ manager.Email });
                        system.debug('email.setCcAddresses');
                    }
                }

                // Set the email subject and body
                email.setSubject('Lead Still not actioned upon');
                email.setPlainTextBody('Dear ' + owner.Name + ',\n\n' +
                                       'This is a notification regarding the lead with the status "Open - Not Contacted" that was created within the last 4 hours.\n\n' +
                                       'Lead Record: ' + URL.getSalesforceBaseUrl().toExternalForm() + '/' + lead.Id + '\n\n' +
                                       'Thank you.\n\n' +
                                       'Best Regards,\n' +
                                       'Your Company');

                // Add the email message to the map using the lead's owner ID as the key
                emailMap.put(lead.OwnerId, email);                
                
            }
            
        }       
        

        // Iterate over the leads in the current batch
        /*
        for (Lead lead : scope) {
            if (lead.Owner.Type == 'User') {
                // Retrieve the lead's owner from the ownerMap
                User owner = ownerMap.get(lead.OwnerId);

                // Create an email message
                Messaging.SingleEmailMessage email = new Messaging.SingleEmailMessage();

                // Set the recipient (owner's email address)
                email.setToAddresses(new List<String>{ owner.Email });

                // Add owner's manager's email to cc recipients if available
                if (owner.ManagerId != null && managerMap.containsKey(owner.ManagerId)) {
                    User manager = managerMap.get(owner.ManagerId);
                    if (manager != null && !String.isBlank(manager.Email)) {
                        email.setCcAddresses(new List<String>{ manager.Email });
                    }
                }

                // Set the email subject and body
                email.setSubject('Lead Still not actioned upon');
                email.setPlainTextBody('Dear ' + owner.Name + ',\n\n' +
                                       'This is a notification regarding the lead with the status "Open - Not Contacted" that was created within the last 4 hours.\n\n' +
                                       'Lead Record: ' + URL.getSalesforceBaseUrl().toExternalForm() + '/' + lead.Id + '\n\n' +
                                       'Thank you.\n\n' +
                                       'Best Regards,\n' +
                                       'Your Company');

                // Add the email message to the map using the lead's owner ID as the key
                emailMap.put(lead.OwnerId, email);
            } else if (lead.Owner.Type == 'Queue') {
                // Retrieve the queue users associated with the lead's queue
                List<User> queueUsers = [SELECT Id, Name, Email, ManagerId
                                         FROM User
                                         WHERE Id IN (SELECT UserOrGroupId
                                                      FROM GroupMember
                                                      WHERE GroupId = :lead.OwnerId)];

                // Iterate over the queue users
                for (User queueUser : queueUsers) {
                    // Create an email message
                    Messaging.SingleEmailMessage email = new Messaging.SingleEmailMessage();

                    // Set the recipient (queue user's email address)
                    email.setToAddresses(new List<String>{ queueUser.Email });

                    // Add queue user's manager's email to cc recipients if available
                    if (queueUser.ManagerId != null && managerMap.containsKey(queueUser.ManagerId)) {
                        User manager = managerMap.get(queueUser.ManagerId);
                        if (manager != null && !String.isBlank(manager.Email)) {
                            email.setCcAddresses(new List<String>{ manager.Email });
                        }
                    }

                    // Set the email subject and body
                    email.setSubject('Lead Still not actioned upon');
                    email.setPlainTextBody('Dear ' + queueUser.Name + ',\n\n' +
                                           'This is a notification regarding the lead with the status "Open - Not Contacted" that was created within the last 4 hours.\n\n' +
                                           'Lead Record: ' + URL.getSalesforceBaseUrl().toExternalForm() + '/' + lead.Id + '\n\n' +
                                           'Thank you.\n\n' +
                                           'Best Regards,\n' +
                                           'Your Company');

                    // Add the email message to the map using the queue user's ID as the key
                    emailMap.put(queueUser.Id, email);

                    // CC the manager of the queue user if available
                    if (queueUser.ManagerId != null && managerMap.containsKey(queueUser.ManagerId)) {
                        User manager = managerMap.get(queueUser.ManagerId);
                        if (manager != null && !String.isBlank(manager.Email)) {
                            emailMap.get(queueUser.Id).setCcAddresses(new List<String>{ manager.Email });
                        }
                    }
                }
            }
        }
		*/

        // Send the email messages
        Messaging.sendEmail(emailMap.values());
    }

    // Finish method for post-processing after the batch job finishes
    public void finish(Database.BatchableContext context) {
        // Do any post-processing after the batch job finishes
    }
}