package com.timeline.user.service;

import com.timeline.user.dao.ReactionMapper;
import com.timeline.user.dao.UserMapper;
import com.timeline.user.entity.Reaction;
import com.timeline.user.entity.User;
import com.timeline.user.service.impl.ReactionServiceImpl;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;

import java.util.*;

import static org.junit.jupiter.api.Assertions.*;
import static org.mockito.ArgumentMatchers.*;
import static org.mockito.Mockito.*;

/**
 * Reaction Service Unit Tests
 */
class ReactionServiceTest {

    @Mock
    private ReactionMapper reactionMapper;

    @Mock
    private UserMapper userMapper;

    @InjectMocks
    private ReactionServiceImpl reactionService;

    @BeforeEach
    void setUp() {
        MockitoAnnotations.openMocks(this);
    }

    @Test
    void testGetReactionSummary_Success() {
        // Arrange
        String entityType = "STORY_ITEM";
        String entityId = "story123";
        String currentUserId = "user1";

        List<Reaction> reactions = new ArrayList<>();
        Reaction reaction1 = new Reaction();
        reaction1.setEntityType(entityType);
        reaction1.setEntityId(entityId);
        reaction1.setUserId("user1");
        reaction1.setReactionType("LIKE");
        reactions.add(reaction1);

        Reaction reaction2 = new Reaction();
        reaction2.setEntityType(entityType);
        reaction2.setEntityId(entityId);
        reaction2.setUserId("user2");
        reaction2.setReactionType("LOVE");
        reactions.add(reaction2);

        when(reactionMapper.findByEntity(entityType, entityId)).thenReturn(reactions);
        when(reactionMapper.findByEntityAndUser(entityType, entityId, currentUserId)).thenReturn(reaction1);

        User user1 = new User();
        user1.setUserId("user1");
        user1.setUsername("User One");
        when(userMapper.selectByUserId("user1")).thenReturn(user1);

        User user2 = new User();
        user2.setUserId("user2");
        user2.setUsername("User Two");
        when(userMapper.selectByUserId("user2")).thenReturn(user2);

        // Act
        Map<String, Object> summary = reactionService.getReactionSummary(entityType, entityId, currentUserId);

        // Assert
        assertNotNull(summary);
        assertEquals(entityType, summary.get("entityType"));
        assertEquals(entityId, summary.get("entityId"));
        assertEquals("LIKE", summary.get("userReaction"));

        @SuppressWarnings("unchecked")
        Map<String, Integer> counts = (Map<String, Integer>) summary.get("counts");
        assertEquals(1, counts.get("LIKE"));
        assertEquals(1, counts.get("LOVE"));
        assertEquals(0, counts.get("LAUGH"));
    }

    @Test
    void testAddOrUpdateReaction_NewReaction() {
        // Arrange
        String userId = "user1";
        String entityType = "PHOTO";
        String entityId = "photo123";
        String reactionType = "LOVE";

        when(reactionMapper.findByEntityAndUser(entityType, entityId, userId)).thenReturn(null);
        when(reactionMapper.insert(any(Reaction.class))).thenReturn(1);

        // Act
        reactionService.addOrUpdateReaction(userId, entityType, entityId, reactionType);

        // Assert
        verify(reactionMapper, times(1)).insert(any(Reaction.class));
        verify(reactionMapper, never()).updateReactionType(anyString(), anyString(), anyString(), anyString());
    }

    @Test
    void testAddOrUpdateReaction_UpdateExisting() {
        // Arrange
        String userId = "user1";
        String entityType = "STORY_ITEM";
        String entityId = "story123";
        String newReactionType = "WOW";

        Reaction existingReaction = new Reaction();
        existingReaction.setEntityType(entityType);
        existingReaction.setEntityId(entityId);
        existingReaction.setUserId(userId);
        existingReaction.setReactionType("LIKE");

        when(reactionMapper.findByEntityAndUser(entityType, entityId, userId)).thenReturn(existingReaction);
        when(reactionMapper.updateReactionType(entityType, entityId, userId, newReactionType)).thenReturn(1);

        // Act
        reactionService.addOrUpdateReaction(userId, entityType, entityId, newReactionType);

        // Assert
        verify(reactionMapper, times(1)).updateReactionType(entityType, entityId, userId, newReactionType);
        verify(reactionMapper, never()).insert(any(Reaction.class));
    }

    @Test
    void testRemoveReaction_Success() {
        // Arrange
        String userId = "user1";
        String entityType = "PHOTO";
        String entityId = "photo123";

        when(reactionMapper.delete(entityType, entityId, userId)).thenReturn(1);

        // Act
        reactionService.removeReaction(userId, entityType, entityId);

        // Assert
        verify(reactionMapper, times(1)).delete(entityType, entityId, userId);
    }

    @Test
    void testAddOrUpdateReaction_InvalidEntityType() {
        // Arrange
        String userId = "user1";
        String entityType = "INVALID_TYPE";
        String entityId = "entity123";
        String reactionType = "LIKE";

        // Act & Assert
        assertThrows(IllegalArgumentException.class, () -> {
            reactionService.addOrUpdateReaction(userId, entityType, entityId, reactionType);
        });
    }

    @Test
    void testAddOrUpdateReaction_InvalidReactionType() {
        // Arrange
        String userId = "user1";
        String entityType = "STORY_ITEM";
        String entityId = "story123";
        String reactionType = "INVALID_REACTION";

        // Act & Assert
        assertThrows(IllegalArgumentException.class, () -> {
            reactionService.addOrUpdateReaction(userId, entityType, entityId, reactionType);
        });
    }

    @Test
    void testGetReactionSummary_OneReactionPerUserConstraint() {
        // Arrange
        String entityType = "STORY_ITEM";
        String entityId = "story123";
        String userId = "user1";

        // User has one reaction
        List<Reaction> reactions = new ArrayList<>();
        Reaction reaction = new Reaction();
        reaction.setEntityType(entityType);
        reaction.setEntityId(entityId);
        reaction.setUserId(userId);
        reaction.setReactionType("LIKE");
        reactions.add(reaction);

        when(reactionMapper.findByEntity(entityType, entityId)).thenReturn(reactions);
        when(reactionMapper.findByEntityAndUser(entityType, entityId, userId)).thenReturn(reaction);

        User user = new User();
        user.setUserId(userId);
        user.setUsername("Test User");
        when(userMapper.selectByUserId(userId)).thenReturn(user);

        // Act
        Map<String, Object> summary = reactionService.getReactionSummary(entityType, entityId, userId);

        // Assert
        assertEquals("LIKE", summary.get("userReaction"));
        
        @SuppressWarnings("unchecked")
        List<Map<String, Object>> recentReactions = (List<Map<String, Object>>) summary.get("recentReactions");
        
        // Verify only one reaction per user
        long userReactionCount = reactions.stream()
                .filter(r -> r.getUserId().equals(userId))
                .count();
        assertEquals(1, userReactionCount);
    }
}