package com.anggastudio.printama.constants;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.robolectric.RobolectricTestRunner;
import org.robolectric.annotation.Config;

import static org.junit.Assert.*;

/**
 * Unit tests for PA (Printama Alignment) constants class
 * Tests all alignment constants and their values
 */
@RunWith(RobolectricTestRunner.class)
@Config(sdk = 28)
public class PATest {

    @Test
    public void testAlignmentConstants() {
        // Test that all alignment constants have correct values
        assertEquals("LEFT alignment should be 0", 0, PA.LEFT);
        assertEquals("CENTER alignment should be -1", -1, PA.CENTER);
        assertEquals("RIGHT alignment should be -2", -2, PA.RIGHT);
    }

    @Test
    public void testConstantsArePublicStaticFinal() {
        // Test that constants are accessible as static fields
        // This test verifies the constants can be accessed without instantiation
        int left = PA.LEFT;
        int center = PA.CENTER;
        int right = PA.RIGHT;
        
        // Verify they are not null/undefined
        assertNotNull("LEFT constant should be accessible", (Integer) left);
        assertNotNull("CENTER constant should be accessible", (Integer) center);
        assertNotNull("RIGHT constant should be accessible", (Integer) right);
    }

    @Test
    public void testConstantsUniqueness() {
        // Test that all constants have unique values
        assertNotEquals("LEFT and CENTER should have different values", PA.LEFT, PA.CENTER);
        assertNotEquals("LEFT and RIGHT should have different values", PA.LEFT, PA.RIGHT);
        assertNotEquals("CENTER and RIGHT should have different values", PA.CENTER, PA.RIGHT);
    }

    @Test
    public void testConstantsRange() {
        // Test that constants are within expected range
        assertTrue("LEFT should be non-negative", PA.LEFT >= 0);
        assertTrue("CENTER should be negative", PA.CENTER < 0);
        assertTrue("RIGHT should be negative", PA.RIGHT < 0);
    }

    @Test
    public void testConstantsOrdering() {
        // Test logical ordering of alignment values
        assertTrue("LEFT should be greater than CENTER", PA.LEFT > PA.CENTER);
        assertTrue("LEFT should be greater than RIGHT", PA.LEFT > PA.RIGHT);
        assertTrue("CENTER should be greater than RIGHT", PA.CENTER > PA.RIGHT);
    }

    @Test
    public void testConstantsInSwitchStatement() {
        // Test that constants can be used in switch statements
        String result;
        
        switch (PA.LEFT) {
            case 0: // PA.LEFT
                result = "left";
                break;
            default:
                result = "unknown";
                break;
        }
        assertEquals("LEFT constant should work in switch", "left", result);
        
        switch (PA.CENTER) {
            case -1: // PA.CENTER
                result = "center";
                break;
            default:
                result = "unknown";
                break;
        }
        assertEquals("CENTER constant should work in switch", "center", result);
        
        switch (PA.RIGHT) {
            case -2: // PA.RIGHT
                result = "right";
                break;
            default:
                result = "unknown";
                break;
        }
        assertEquals("RIGHT constant should work in switch", "right", result);
    }

    @Test
    public void testConstantsInArrays() {
        // Test that constants can be used in arrays
        int[] alignments = {PA.LEFT, PA.CENTER, PA.RIGHT};
        
        assertEquals("Array should contain LEFT", PA.LEFT, alignments[0]);
        assertEquals("Array should contain CENTER", PA.CENTER, alignments[1]);
        assertEquals("Array should contain RIGHT", PA.RIGHT, alignments[2]);
    }

    @Test
    public void testConstantsComparison() {
        // Test comparison operations with constants
        assertTrue("LEFT == 0", PA.LEFT == 0);
        assertTrue("CENTER == -1", PA.CENTER == -1);
        assertTrue("RIGHT == -2", PA.RIGHT == -2);
        
        assertFalse("LEFT != CENTER", PA.LEFT == PA.CENTER);
        assertFalse("LEFT != RIGHT", PA.LEFT == PA.RIGHT);
        assertFalse("CENTER != RIGHT", PA.CENTER == PA.RIGHT);
    }

    @Test
    public void testConstantsAsMethodParameters() {
        // Test that constants can be passed as method parameters
        assertEquals("LEFT should be valid parameter", 0, getAlignmentValue(PA.LEFT));
        assertEquals("CENTER should be valid parameter", -1, getAlignmentValue(PA.CENTER));
        assertEquals("RIGHT should be valid parameter", -2, getAlignmentValue(PA.RIGHT));
    }

    @Test
    public void testConstantsImmutability() {
        // Test that constants maintain their values
        int originalLeft = PA.LEFT;
        int originalCenter = PA.CENTER;
        int originalRight = PA.RIGHT;
        
        // Simulate some operations that might affect constants
        performDummyOperations();
        
        // Verify constants haven't changed
        assertEquals("LEFT should remain unchanged", originalLeft, PA.LEFT);
        assertEquals("CENTER should remain unchanged", originalCenter, PA.CENTER);
        assertEquals("RIGHT should remain unchanged", originalRight, PA.RIGHT);
    }

    @Test
    public void testConstantsDocumentationValues() {
        // Test that constants match their documented values
        // Based on the documentation in PA.java
        assertEquals("LEFT should be 0 as documented", 0, PA.LEFT);
        assertEquals("CENTER should be -1 as documented", -1, PA.CENTER);
        assertEquals("RIGHT should be -2 as documented", -2, PA.RIGHT);
    }

    @Test
    public void testConstantsPerformance() {
        // Test that accessing constants is fast (no computation involved)
        long startTime = System.nanoTime();
        
        // Access constants multiple times
        for (int i = 0; i < 1000; i++) {
            int left = PA.LEFT;
            int center = PA.CENTER;
            int right = PA.RIGHT;
        }
        
        long endTime = System.nanoTime();
        long duration = endTime - startTime;
        
        // Should be very fast (less than 1ms for 1000 accesses)
        assertTrue("Constant access should be fast", duration < 1_000_000); // 1ms in nanoseconds
    }

    // Helper methods for testing
    private int getAlignmentValue(int alignment) {
        return alignment;
    }
    
    private void performDummyOperations() {
        // Simulate some operations
        int temp = 0;
        for (int i = 0; i < 100; i++) {
            temp += i;
        }
    }
}