-- ═══════════════════════════════════════════════════════════════════════════════
-- POLYMORPHIC RELATIONSHIP QUERIES (TYPEOF Pattern)
-- ═══════════════════════════════════════════════════════════════════════════════
--
-- Polymorphic lookups can point to multiple object types.
-- Use TYPEOF to access object-specific fields based on the actual type.
--
-- COMMON POLYMORPHIC FIELDS:
-- • Who (WhoId) - Task/Event → Contact OR Lead
-- • What (WhatId) - Task/Event → Account, Opportunity, Case, etc.
-- • Owner (OwnerId) - Most objects → User OR Queue
-- • Related (RelatedToId) - Various → Multiple objects
--
-- USE WHEN:
-- • Querying Task, Event, or other objects with polymorphic lookups
-- • Need type-specific fields from the related record
-- • Building reports that span multiple related object types
--
-- ═══════════════════════════════════════════════════════════════════════════════

-- ───────────────────────────────────────────────────────────────────────────────
-- BASIC TYPEOF: Task with Who (Contact vs Lead)
-- ───────────────────────────────────────────────────────────────────────────────
SELECT Id, Subject, Status, ActivityDate,
    TYPEOF Who
        WHEN Contact THEN FirstName, LastName, Email, Account.Name
        WHEN Lead THEN FirstName, LastName, Email, Company
    END
FROM Task
WHERE Status != 'Completed'
AND ActivityDate >= TODAY

-- ───────────────────────────────────────────────────────────────────────────────
-- TYPEOF with What (Account, Opportunity, Case)
-- ───────────────────────────────────────────────────────────────────────────────
SELECT Id, Subject, Status, Priority,
    TYPEOF What
        WHEN Account THEN Name, Industry, AnnualRevenue, Type
        WHEN Opportunity THEN Name, StageName, Amount, CloseDate
        WHEN Case THEN CaseNumber, Subject, Status, Priority
    END
FROM Task
WHERE CreatedDate = THIS_WEEK
ORDER BY ActivityDate ASC

-- ───────────────────────────────────────────────────────────────────────────────
-- FULL TYPEOF: Both Who and What in same query
-- ───────────────────────────────────────────────────────────────────────────────
SELECT Id, Subject, Status, ActivityDate, Priority,
    Owner.Name,
    TYPEOF Who
        WHEN Contact THEN
            FirstName, LastName, Email, Phone,
            Account.Name, Account.Industry
        WHEN Lead THEN
            FirstName, LastName, Email, Company, Status
    END,
    TYPEOF What
        WHEN Account THEN Name, Industry, Type, BillingCity
        WHEN Opportunity THEN Name, StageName, Amount, Probability
        WHEN Case THEN CaseNumber, Subject, Status
        WHEN Campaign THEN Name, Status, Type
    END
FROM Task
WHERE OwnerId = :currentUserId
AND Status = 'Not Started'
ORDER BY ActivityDate ASC
LIMIT 100

-- ───────────────────────────────────────────────────────────────────────────────
-- EVENT with polymorphic relationships
-- ───────────────────────────────────────────────────────────────────────────────
SELECT Id, Subject, StartDateTime, EndDateTime, Location,
    TYPEOF Who
        WHEN Contact THEN FirstName, LastName, Email, Title
        WHEN Lead THEN FirstName, LastName, Company
    END,
    TYPEOF What
        WHEN Account THEN Name, Phone, Website
        WHEN Opportunity THEN Name, StageName, Amount
    END
FROM Event
WHERE StartDateTime >= TODAY
AND StartDateTime <= NEXT_MONTH
ORDER BY StartDateTime ASC

-- ───────────────────────────────────────────────────────────────────────────────
-- Using ELSE clause for unhandled types
-- ───────────────────────────────────────────────────────────────────────────────
SELECT Id, Subject, Status,
    TYPEOF What
        WHEN Account THEN Name, Industry
        WHEN Opportunity THEN Name, StageName
        WHEN Case THEN CaseNumber
        ELSE Name
    END
FROM Task
WHERE ActivityDate = TODAY

-- ───────────────────────────────────────────────────────────────────────────────
-- FeedItem with polymorphic Parent
-- ───────────────────────────────────────────────────────────────────────────────
SELECT Id, Body, CreatedDate, CreatedBy.Name,
    TYPEOF Parent
        WHEN Account THEN Name, Industry
        WHEN Opportunity THEN Name, StageName
        WHEN Case THEN CaseNumber, Subject
        WHEN Contact THEN FirstName, LastName
        WHEN Lead THEN FirstName, LastName, Company
        WHEN User THEN Name, Title
    END
FROM FeedItem
WHERE CreatedDate = THIS_WEEK
ORDER BY CreatedDate DESC
LIMIT 50

-- ───────────────────────────────────────────────────────────────────────────────
-- ContentDocumentLink with polymorphic LinkedEntity
-- ───────────────────────────────────────────────────────────────────────────────
SELECT Id, ContentDocument.Title, ContentDocument.FileType,
    TYPEOF LinkedEntity
        WHEN Account THEN Name, Industry
        WHEN Contact THEN FirstName, LastName
        WHEN Opportunity THEN Name, Amount
        WHEN Case THEN CaseNumber, Subject
    END
FROM ContentDocumentLink
WHERE ContentDocument.FileType = 'PDF'
ORDER BY ContentDocument.CreatedDate DESC
LIMIT 100

-- ═══════════════════════════════════════════════════════════════════════════════
-- ALTERNATIVE: Check Type.Name without TYPEOF
-- Use when you only need to identify the type, not access specific fields
-- ═══════════════════════════════════════════════════════════════════════════════
SELECT Id, Subject, Status,
    Who.Type,
    Who.Name,
    What.Type,
    What.Name
FROM Task
WHERE ActivityDate = TODAY

-- ═══════════════════════════════════════════════════════════════════════════════
-- APEX PROCESSING PATTERN
-- ═══════════════════════════════════════════════════════════════════════════════
/*
// Query with TYPEOF
List<Task> tasks = [
    SELECT Id, Subject,
        TYPEOF Who
            WHEN Contact THEN FirstName, LastName, Email
            WHEN Lead THEN FirstName, LastName, Company
        END
    FROM Task
    WHERE ActivityDate = TODAY
];

// Process based on type
for (Task t : tasks) {
    if (t.WhoId != null) {
        Schema.SObjectType whoType = t.WhoId.getSObjectType();

        if (whoType == Contact.SObjectType) {
            Contact con = (Contact) t.getSObject('Who');
            System.debug('Contact: ' + con.FirstName + ' ' + con.LastName);
        }
        else if (whoType == Lead.SObjectType) {
            Lead lead = (Lead) t.getSObject('Who');
            System.debug('Lead: ' + lead.FirstName + ' at ' + lead.Company);
        }
    }
}
*/

-- ═══════════════════════════════════════════════════════════════════════════════
-- APEX ALTERNATIVE: Using instanceof
-- ═══════════════════════════════════════════════════════════════════════════════
/*
for (Task t : tasks) {
    SObject who = t.getSObject('Who');
    if (who instanceof Contact) {
        Contact con = (Contact) who;
        System.debug('Contact: ' + con.Email);
    } else if (who instanceof Lead) {
        Lead lead = (Lead) who;
        System.debug('Lead Company: ' + lead.Company);
    }
}
*/

-- ═══════════════════════════════════════════════════════════════════════════════
-- SF CLI USAGE
-- ═══════════════════════════════════════════════════════════════════════════════
-- sf data query \
--   --query "SELECT Id, Subject, TYPEOF Who WHEN Contact THEN FirstName, LastName WHEN Lead THEN Company END FROM Task WHERE ActivityDate = TODAY LIMIT 10" \
--   --target-org myorg \
--   --json