<?php

declare(strict_types=1);

echo "Testing PostgreSQL Generated Columns (STORED)\n";
echo "==============================================\n\n";

try {
    // Create PDO connection
    $pdo = new PDO(
        'pgsql:host=db;dbname=michaelschiemer',
        'postgres',
        'StartSimple2024!'
    );
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    echo "✅ Database connection established\n\n";

    // Cleanup
    echo "Cleaning up existing test tables...\n";
    $pdo->exec("DROP TABLE IF EXISTS test_users");
    $pdo->exec("DROP TABLE IF EXISTS test_products");
    $pdo->exec("DROP TABLE IF EXISTS test_orders");
    $pdo->exec("DROP TABLE IF EXISTS test_documents");
    echo "✅ Cleanup complete\n\n";

    // Test 1: String concatenation (full name from first + last name)
    echo "Test 1: String Concatenation\n";
    echo "=============================\n";
    $pdo->exec("
        CREATE TABLE test_users (
            id SERIAL PRIMARY KEY,
            first_name VARCHAR(100) NOT NULL,
            last_name VARCHAR(100) NOT NULL,
            full_name VARCHAR(201) GENERATED ALWAYS AS (first_name || ' ' || last_name) STORED,
            email VARCHAR(200) NOT NULL,
            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
        )
    ");
    echo "✅ Table created with generated full_name column\n";

    // Insert data
    $pdo->exec("
        INSERT INTO test_users (first_name, last_name, email) VALUES
        ('John', 'Doe', 'john.doe@example.com'),
        ('Jane', 'Smith', 'jane.smith@example.com'),
        ('Bob', 'Johnson', 'bob.johnson@example.com')
    ");
    echo "✅ Test users inserted\n";

    // Query generated columns
    $stmt = $pdo->query("SELECT first_name, last_name, full_name FROM test_users ORDER BY id");
    $results = $stmt->fetchAll(PDO::FETCH_ASSOC);
    echo "   Generated full names:\n";
    foreach ($results as $row) {
        echo "   - {$row['first_name']} {$row['last_name']} → {$row['full_name']}\n";
    }
    echo "\n";

    // Test auto-update: Update first_name and verify full_name updates
    echo "Testing auto-update: Changing John's last name...\n";
    $pdo->exec("UPDATE test_users SET last_name = 'Williams' WHERE first_name = 'John'");
    $stmt = $pdo->query("SELECT full_name FROM test_users WHERE first_name = 'John'");
    $result = $stmt->fetch(PDO::FETCH_ASSOC);
    echo "   New full name: {$result['full_name']}\n";
    echo "✅ Generated column auto-updated\n\n";

    // Test 2: Mathematical calculations
    echo "Test 2: Mathematical Calculations\n";
    echo "==================================\n";
    $pdo->exec("
        CREATE TABLE test_products (
            id SERIAL PRIMARY KEY,
            name VARCHAR(200) NOT NULL,
            price NUMERIC(10,2) NOT NULL,
            tax_rate NUMERIC(5,4) NOT NULL DEFAULT 0.19,
            price_incl_tax NUMERIC(10,2) GENERATED ALWAYS AS (price * (1 + tax_rate)) STORED,
            discount_percent INTEGER DEFAULT 0,
            final_price NUMERIC(10,2) GENERATED ALWAYS AS (
                price * (1 + tax_rate) * (1 - discount_percent / 100.0)
            ) STORED,
            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
        )
    ");
    echo "✅ Table created with calculated price columns\n";

    // Insert products
    $pdo->exec("
        INSERT INTO test_products (name, price, tax_rate, discount_percent) VALUES
        ('Laptop', 999.99, 0.19, 10),
        ('Mouse', 29.99, 0.19, 0),
        ('Keyboard', 79.99, 0.19, 15)
    ");
    echo "✅ Test products inserted\n";

    // Query calculated prices
    $stmt = $pdo->query("
        SELECT name, price, tax_rate, discount_percent, price_incl_tax, final_price
        FROM test_products
        ORDER BY id
    ");
    $results = $stmt->fetchAll(PDO::FETCH_ASSOC);
    echo "   Calculated prices:\n";
    foreach ($results as $row) {
        echo "   - {$row['name']}\n";
        echo "     Base: €{$row['price']}, Tax: {$row['tax_rate']}, Discount: {$row['discount_percent']}%\n";
        echo "     With tax: €{$row['price_incl_tax']}, Final: €{$row['final_price']}\n\n";
    }

    // Test 3: Status calculation based on numeric values
    echo "Test 3: Numeric Status Calculation\n";
    echo "===================================\n";
    $pdo->exec("
        CREATE TABLE test_orders (
            id SERIAL PRIMARY KEY,
            order_number VARCHAR(50) NOT NULL,
            total_amount NUMERIC(10,2) NOT NULL,
            items_count INTEGER NOT NULL,
            average_item_price NUMERIC(10,2) GENERATED ALWAYS AS (
                total_amount / NULLIF(items_count, 0)
            ) STORED,
            order_status VARCHAR(20) GENERATED ALWAYS AS (
                CASE
                    WHEN total_amount < 50 THEN 'small'
                    WHEN total_amount < 200 THEN 'medium'
                    ELSE 'large'
                END
            ) STORED,
            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
        )
    ");
    echo "✅ Table created with calculated status columns\n";

    // Insert orders
    $pdo->exec("
        INSERT INTO test_orders (order_number, total_amount, items_count) VALUES
        ('ORD-001', 29.99, 2),
        ('ORD-002', 149.50, 5),
        ('ORD-003', 599.99, 3)
    ");
    echo "✅ Test orders inserted\n";

    // Query calculated values
    $stmt = $pdo->query("
        SELECT order_number, total_amount, items_count, average_item_price, order_status
        FROM test_orders
        ORDER BY id
    ");
    $results = $stmt->fetchAll(PDO::FETCH_ASSOC);
    echo "   Calculated order statistics:\n";
    foreach ($results as $row) {
        echo "   - {$row['order_number']}: Total €{$row['total_amount']}, ";
        echo "{$row['items_count']} items, Avg €{$row['average_item_price']} → Status: {$row['order_status']}\n";
    }
    echo "\n";

    // Test 4: JSONB field extraction
    echo "Test 4: JSONB Field Extraction\n";
    echo "===============================\n";
    $pdo->exec("
        CREATE TABLE test_documents (
            id SERIAL PRIMARY KEY,
            title VARCHAR(200) NOT NULL,
            metadata JSONB NOT NULL,
            author VARCHAR(200) GENERATED ALWAYS AS (metadata->>'author') STORED,
            created_year INTEGER GENERATED ALWAYS AS ((metadata->>'year')::INTEGER) STORED,
            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
        )
    ");
    echo "✅ Table created with JSONB extraction columns\n";

    // Insert documents
    $pdo->exec("
        INSERT INTO test_documents (title, metadata) VALUES
        ('The Art of Programming', '{\"author\": \"Donald Knuth\", \"year\": 1968, \"pages\": 650}'),
        ('Clean Code', '{\"author\": \"Robert C. Martin\", \"year\": 2008, \"pages\": 464}'),
        ('Design Patterns', '{\"author\": \"Gang of Four\", \"year\": 1994, \"pages\": 395}')
    ");
    echo "✅ Test documents inserted\n";

    // Query extracted fields
    $stmt = $pdo->query("
        SELECT title, author, created_year
        FROM test_documents
        ORDER BY created_year
    ");
    $results = $stmt->fetchAll(PDO::FETCH_ASSOC);
    echo "   Extracted JSONB fields:\n";
    foreach ($results as $row) {
        echo "   - {$row['title']} by {$row['author']} ({$row['created_year']})\n";
    }
    echo "\n";

    // Test 5: Cannot manually update generated columns
    echo "Test 5: Immutability Test (Generated Columns Cannot Be Updated)\n";
    echo "================================================================\n";
    try {
        $pdo->exec("UPDATE test_users SET full_name = 'Manual Name' WHERE id = 1");
        echo "❌ ERROR: Should not allow manual updates to generated columns\n";
    } catch (\PDOException $e) {
        if (str_contains($e->getMessage(), 'cannot insert a non-DEFAULT value into column') ||
            str_contains($e->getMessage(), 'column') && str_contains($e->getMessage(), 'can only be updated to DEFAULT')) {
            echo "✅ Correctly prevented manual update of generated column\n";
            echo "   Error message: " . $e->getMessage() . "\n\n";
        } else {
            throw $e;
        }
    }

    // Test 6: Complex expression with CASE (referencing base columns, not generated columns)
    echo "Test 6: Complex Expression with CASE\n";
    echo "=====================================\n";
    $pdo->exec("ALTER TABLE test_products ADD COLUMN price_category VARCHAR(20) GENERATED ALWAYS AS (
        CASE
            WHEN (price * (1 + tax_rate) * (1 - discount_percent / 100.0)) < 50 THEN 'Budget'
            WHEN (price * (1 + tax_rate) * (1 - discount_percent / 100.0)) < 200 THEN 'Mid-Range'
            ELSE 'Premium'
        END
    ) STORED");
    echo "✅ Added price_category generated column with CASE expression\n";

    // Query categorized products
    $stmt = $pdo->query("
        SELECT name, final_price, price_category
        FROM test_products
        ORDER BY final_price
    ");
    $results = $stmt->fetchAll(PDO::FETCH_ASSOC);
    echo "   Product categories:\n";
    foreach ($results as $row) {
        echo "   - {$row['name']}: €{$row['final_price']} → {$row['price_category']}\n";
    }
    echo "\n";

    // Cleanup
    echo "Cleaning up...\n";
    $pdo->exec("DROP TABLE IF EXISTS test_users");
    $pdo->exec("DROP TABLE IF EXISTS test_products");
    $pdo->exec("DROP TABLE IF EXISTS test_orders");
    $pdo->exec("DROP TABLE IF EXISTS test_documents");
    echo "✅ Test tables dropped\n";

    echo "\n✅ All Generated Column tests passed!\n";
    echo "\nSummary:\n";
    echo "========\n";
    echo "✅ GENERATED ALWAYS AS ... STORED syntax works\n";
    echo "✅ String concatenation in generated columns works\n";
    echo "✅ Mathematical calculations work\n";
    echo "✅ Numeric status calculations work\n";
    echo "✅ JSONB field extraction works\n";
    echo "✅ Complex CASE expressions work\n";
    echo "✅ Generated columns auto-update when source columns change\n";
    echo "✅ Generated columns cannot be manually updated (immutable)\n";
    echo "✅ Generated columns can be added with ALTER TABLE\n";

} catch (\Exception $e) {
    echo "❌ Error: " . $e->getMessage() . "\n";
    echo "Stack trace:\n" . $e->getTraceAsString() . "\n";
    exit(1);
}