package dev.openfeature.sdk;

import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;

import java.util.HashMap;

import static dev.openfeature.sdk.EvaluationContext.TARGETING_KEY;
import static org.junit.jupiter.api.Assertions.assertArrayEquals;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;

class ImmutableContextTest {

    @DisplayName("attributes mutation should not affect the immutable context")
    @Test
    void shouldCreateCopyOfAttributesForImmutableContext() {
        HashMap<String, Value> attributes = new HashMap<>();
        attributes.put("key1", new Value("val1"));
        attributes.put("key2", new Value("val2"));
        EvaluationContext ctx = new ImmutableContext("targeting key", attributes);
        attributes.put("key3", new Value("val3"));
        assertArrayEquals(new Object[]{"key1", "key2", TARGETING_KEY}, ctx.keySet().toArray());
    }

    @DisplayName("targeting key should be changed from the overriding context")
    @Test
    void shouldChangeTargetingKeyFromOverridingContext() {
        HashMap<String, Value> attributes = new HashMap<>();
        attributes.put("key1", new Value("val1"));
        attributes.put("key2", new Value("val2"));
        EvaluationContext ctx = new ImmutableContext("targeting key", attributes);
        EvaluationContext overriding = new ImmutableContext("overriding_key");
        EvaluationContext merge = ctx.merge(overriding);
        assertEquals("overriding_key", merge.getTargetingKey());
    }

    @DisplayName("targeting key should not changed from the overriding context if missing")
    @Test
    void shouldRetainTargetingKeyWhenOverridingContextTargetingKeyValueIsEmpty() {
        HashMap<String, Value> attributes = new HashMap<>();
        attributes.put("key1", new Value("val1"));
        attributes.put("key2", new Value("val2"));
        EvaluationContext ctx = new ImmutableContext("targeting_key", attributes);
        EvaluationContext overriding = new ImmutableContext("");
        EvaluationContext merge = ctx.merge(overriding);
        assertEquals("targeting_key", merge.getTargetingKey());
    }
    @DisplayName("missing targeting key should return null")
    @Test
    void missingTargetingKeyShould() {
        EvaluationContext ctx = new ImmutableContext();
        assertEquals(null, ctx.getTargetingKey());
    }

    @DisplayName("Merge should retain all the attributes from the existing context when overriding context is null")
    @Test
    void mergeShouldReturnAllTheValuesFromTheContextWhenOverridingContextIsNull() {
        HashMap<String, Value> attributes = new HashMap<>();
        attributes.put("key1", new Value("val1"));
        attributes.put("key2", new Value("val2"));
        EvaluationContext ctx = new ImmutableContext("targeting_key", attributes);
        EvaluationContext merge = ctx.merge(null);
        assertEquals("targeting_key", merge.getTargetingKey());
        assertArrayEquals(new Object[]{"key1", "key2", TARGETING_KEY}, merge.keySet().toArray());
    }

    @DisplayName("Merge should retain subkeys from the existing context when the overriding context has the same targeting key")
    @Test
    void mergeShouldRetainItsSubkeysWhenOverridingContextHasTheSameKey() {
        HashMap<String, Value> attributes = new HashMap<>();
        HashMap<String, Value> overridingAttributes = new HashMap<>();
        HashMap<String, Value> key1Attributes = new HashMap<>();
        HashMap<String, Value> ovKey1Attributes = new HashMap<>();

        key1Attributes.put("key1_1", new Value("val1_1"));
        attributes.put("key1", new Value(new ImmutableStructure(key1Attributes)));
        attributes.put("key2", new Value("val2"));
        ovKey1Attributes.put("overriding_key1_1", new Value("overriding_val_1_1"));
        overridingAttributes.put("key1", new Value(new ImmutableStructure(ovKey1Attributes)));
        
        EvaluationContext ctx = new ImmutableContext("targeting_key", attributes);
        EvaluationContext overriding = new ImmutableContext("targeting_key", overridingAttributes);
        EvaluationContext merge = ctx.merge(overriding);
        assertEquals("targeting_key", merge.getTargetingKey());
        assertArrayEquals(new Object[]{"key1", "key2", TARGETING_KEY}, merge.keySet().toArray());
        
        Value key1 = merge.getValue("key1");
        assertTrue(key1.isStructure());
        
        Structure value = key1.asStructure();
        assertArrayEquals(new Object[]{"key1_1","overriding_key1_1"}, value.keySet().toArray());
    }
    
    @DisplayName("Merge should retain subkeys from the existing context when the overriding context doesn't have targeting key")
    @Test
    void mergeShouldRetainItsSubkeysWhenOverridingContextHasNoTargetingKey() {
        HashMap<String, Value> attributes = new HashMap<>();
        HashMap<String, Value> key1Attributes = new HashMap<>();

        key1Attributes.put("key1_1", new Value("val1_1"));
        attributes.put("key1", new Value(new ImmutableStructure(key1Attributes)));
        attributes.put("key2", new Value("val2"));
        
        EvaluationContext ctx = new ImmutableContext(attributes);
        EvaluationContext overriding = new ImmutableContext();
        EvaluationContext merge = ctx.merge(overriding);
        assertArrayEquals(new Object[]{"key1", "key2"}, merge.keySet().toArray());
        
        Value key1 = merge.getValue("key1");
        assertTrue(key1.isStructure());
        
        Structure value = key1.asStructure();
        assertArrayEquals(new Object[]{"key1_1"}, value.keySet().toArray());
    }
}