package com.recipeapp.planning;

import com.recipeapp.auth.UserAccountRepository;
import com.recipeapp.auth.entity.UserAccount;
import com.recipeapp.common.ConflictException;
import com.recipeapp.common.ResourceNotFoundException;
import com.recipeapp.common.ValidationException;
import com.recipeapp.household.HouseholdRepository;
import com.recipeapp.household.entity.Household;
import com.recipeapp.planning.dto.*;
import com.recipeapp.planning.entity.*;
import com.recipeapp.recipe.RecipeRepository;
import com.recipeapp.recipe.entity.*;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.junit.jupiter.MockitoExtension;
import org.springframework.data.domain.PageRequest;

import java.math.BigDecimal;
import java.time.LocalDate;
import java.util.*;

import static org.assertj.core.api.Assertions.*;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.Mockito.*;

@ExtendWith(MockitoExtension.class)
class PlanningServiceTest {

    @Mock private WeekPlanRepository weekPlanRepository;
    @Mock private WeekPlanSlotRepository weekPlanSlotRepository;
    @Mock private CookingLogRepository cookingLogRepository;
    @Mock private RecipeRepository recipeRepository;
    @Mock private HouseholdRepository householdRepository;
    @Mock private UserAccountRepository userAccountRepository;
    @Mock private VarietyScoreConfigRepository varietyScoreConfigRepository;

    @InjectMocks private PlanningService planningService;

    private static final UUID HOUSEHOLD_ID = UUID.randomUUID();
    private static final LocalDate WEEK_START = LocalDate.of(2026, 4, 6); // Monday

    private Household testHousehold() {
        var h = new Household("Test family", null);
        setId(h, Household.class, HOUSEHOLD_ID);
        return h;
    }

    private WeekPlan testWeekPlan(Household household) {
        var wp = new WeekPlan(household, WEEK_START);
        setId(wp, WeekPlan.class, UUID.randomUUID());
        return wp;
    }

    private Recipe testRecipe(Household household, String name) {
        var r = new Recipe(household, name, (short) 4, (short) 45, "medium", true);
        setId(r, Recipe.class, UUID.randomUUID());
        return r;
    }

    private <T> void setId(T entity, Class<T> clazz, UUID id) {
        try {
            var field = clazz.getDeclaredField("id");
            field.setAccessible(true);
            field.set(entity, id);
        } catch (Exception e) { throw new RuntimeException(e); }
    }

    // ── Week Plan CRUD ──

    @Test
    void getWeekPlanShouldReturnPlanWithSlots() {
        var household = testHousehold();
        var plan = testWeekPlan(household);
        var recipe = testRecipe(household, "Spaghetti");
        var slot = new WeekPlanSlot(plan, recipe, WEEK_START);
        setId(slot, WeekPlanSlot.class, UUID.randomUUID());
        plan.getSlots().add(slot);

        when(weekPlanRepository.findByHouseholdIdAndWeekStart(HOUSEHOLD_ID, WEEK_START))
                .thenReturn(Optional.of(plan));

        WeekPlanResponse result = planningService.getWeekPlan(HOUSEHOLD_ID, WEEK_START);

        assertThat(result.weekStart()).isEqualTo(WEEK_START);
        assertThat(result.slots()).hasSize(1);
        assertThat(result.slots().getFirst().recipe().name()).isEqualTo("Spaghetti");
    }

    @Test
    void getWeekPlanShouldThrowWhenNotFound() {
        when(weekPlanRepository.findByHouseholdIdAndWeekStart(HOUSEHOLD_ID, WEEK_START))
                .thenReturn(Optional.empty());

        assertThatThrownBy(() -> planningService.getWeekPlan(HOUSEHOLD_ID, WEEK_START))
                .isInstanceOf(ResourceNotFoundException.class);
    }

    @Test
    void createWeekPlanShouldPersist() {
        var household = testHousehold();

        when(weekPlanRepository.existsByHouseholdIdAndWeekStart(HOUSEHOLD_ID, WEEK_START)).thenReturn(false);
        when(householdRepository.findById(HOUSEHOLD_ID)).thenReturn(Optional.of(household));
        when(weekPlanRepository.save(any(WeekPlan.class))).thenAnswer(i -> {
            WeekPlan wp = i.getArgument(0);
            setId(wp, WeekPlan.class, UUID.randomUUID());
            return wp;
        });

        WeekPlanResponse result = planningService.createWeekPlan(HOUSEHOLD_ID, WEEK_START);

        assertThat(result.weekStart()).isEqualTo(WEEK_START);
        assertThat(result.status()).isEqualTo("draft");
    }

    @Test
    void createWeekPlanShouldThrowConflictWhenExists() {
        when(weekPlanRepository.existsByHouseholdIdAndWeekStart(HOUSEHOLD_ID, WEEK_START)).thenReturn(true);

        assertThatThrownBy(() -> planningService.createWeekPlan(HOUSEHOLD_ID, WEEK_START))
                .isInstanceOf(ConflictException.class);
    }

    @Test
    void createWeekPlanShouldThrowWhenNotMonday() {
        var tuesday = LocalDate.of(2026, 4, 7);

        assertThatThrownBy(() -> planningService.createWeekPlan(HOUSEHOLD_ID, tuesday))
                .isInstanceOf(ValidationException.class);
    }

    // ── Slots ──

    @Test
    void addSlotShouldCreateSlot() {
        var household = testHousehold();
        var plan = testWeekPlan(household);
        var recipe = testRecipe(household, "Spaghetti");

        when(weekPlanRepository.findById(plan.getId())).thenReturn(Optional.of(plan));
        when(recipeRepository.findByIdAndHouseholdIdAndDeletedAtIsNull(recipe.getId(), HOUSEHOLD_ID))
                .thenReturn(Optional.of(recipe));
        when(weekPlanSlotRepository.save(any(WeekPlanSlot.class))).thenAnswer(i -> {
            WeekPlanSlot s = i.getArgument(0);
            setId(s, WeekPlanSlot.class, UUID.randomUUID());
            return s;
        });

        SlotResponse result = planningService.addSlot(HOUSEHOLD_ID, plan.getId(),
                new CreateSlotRequest(WEEK_START.plusDays(1), recipe.getId()));

        assertThat(result.recipe().name()).isEqualTo("Spaghetti");
    }

    @Test
    void updateSlotShouldSwapRecipe() {
        var household = testHousehold();
        var plan = testWeekPlan(household);
        var oldRecipe = testRecipe(household, "Spaghetti");
        var newRecipe = testRecipe(household, "Stir Fry");
        var slot = new WeekPlanSlot(plan, oldRecipe, WEEK_START);
        setId(slot, WeekPlanSlot.class, UUID.randomUUID());
        plan.getSlots().add(slot);

        when(weekPlanRepository.findById(plan.getId())).thenReturn(Optional.of(plan));
        when(weekPlanSlotRepository.findById(slot.getId())).thenReturn(Optional.of(slot));
        when(recipeRepository.findByIdAndHouseholdIdAndDeletedAtIsNull(newRecipe.getId(), HOUSEHOLD_ID))
                .thenReturn(Optional.of(newRecipe));

        SlotResponse result = planningService.updateSlot(HOUSEHOLD_ID, plan.getId(), slot.getId(),
                new UpdateSlotRequest(newRecipe.getId()));

        assertThat(result.recipe().name()).isEqualTo("Stir Fry");
    }

    @Test
    void deleteSlotShouldRemoveSlot() {
        var household = testHousehold();
        var plan = testWeekPlan(household);
        var slot = new WeekPlanSlot(plan, testRecipe(household, "X"), WEEK_START);
        setId(slot, WeekPlanSlot.class, UUID.randomUUID());
        plan.getSlots().add(slot);

        when(weekPlanRepository.findById(plan.getId())).thenReturn(Optional.of(plan));
        when(weekPlanSlotRepository.findById(slot.getId())).thenReturn(Optional.of(slot));

        planningService.deleteSlot(HOUSEHOLD_ID, plan.getId(), slot.getId());

        verify(weekPlanSlotRepository).delete(slot);
    }

    // ── Confirm ──

    @Test
    void confirmPlanShouldSetStatusAndTimestamp() {
        var household = testHousehold();
        var plan = testWeekPlan(household);
        var slot = new WeekPlanSlot(plan, testRecipe(household, "X"), WEEK_START);
        setId(slot, WeekPlanSlot.class, UUID.randomUUID());
        plan.getSlots().add(slot);

        when(weekPlanRepository.findById(plan.getId())).thenReturn(Optional.of(plan));

        WeekPlanResponse result = planningService.confirmPlan(HOUSEHOLD_ID, plan.getId());

        assertThat(result.status()).isEqualTo("confirmed");
        assertThat(result.confirmedAt()).isNotNull();
    }

    @Test
    void confirmPlanShouldThrowWhenNoSlots() {
        var household = testHousehold();
        var plan = testWeekPlan(household);

        when(weekPlanRepository.findById(plan.getId())).thenReturn(Optional.of(plan));

        assertThatThrownBy(() -> planningService.confirmPlan(HOUSEHOLD_ID, plan.getId()))
                .isInstanceOf(ValidationException.class);
    }

    @Test
    void confirmPlanShouldThrowWhenAlreadyConfirmed() {
        var household = testHousehold();
        var plan = testWeekPlan(household);
        plan.setStatus("confirmed");
        var slot = new WeekPlanSlot(plan, testRecipe(household, "X"), WEEK_START);
        setId(slot, WeekPlanSlot.class, UUID.randomUUID());
        plan.getSlots().add(slot);

        when(weekPlanRepository.findById(plan.getId())).thenReturn(Optional.of(plan));

        assertThatThrownBy(() -> planningService.confirmPlan(HOUSEHOLD_ID, plan.getId()))
                .isInstanceOf(ValidationException.class);
    }

    // ── Cooking Logs ──

    @Test
    void createCookingLogShouldPersist() {
        var household = testHousehold();
        var recipe = testRecipe(household, "Spaghetti");
        var user = new UserAccount("sarah@example.com", "Sarah", "hashed");
        setId(user, UserAccount.class, UUID.randomUUID());

        when(recipeRepository.findById(recipe.getId())).thenReturn(Optional.of(recipe));
        when(householdRepository.findById(HOUSEHOLD_ID)).thenReturn(Optional.of(household));
        when(userAccountRepository.findById(user.getId())).thenReturn(Optional.of(user));
        when(cookingLogRepository.save(any(CookingLog.class))).thenAnswer(i -> {
            CookingLog cl = i.getArgument(0);
            setId(cl, CookingLog.class, UUID.randomUUID());
            return cl;
        });

        CookingLogResponse result = planningService.createCookingLog(HOUSEHOLD_ID, user.getId(),
                new CreateCookingLogRequest(recipe.getId(), LocalDate.of(2026, 4, 7)));

        assertThat(result.recipeName()).isEqualTo("Spaghetti");
        assertThat(result.cookedOn()).isEqualTo(LocalDate.of(2026, 4, 7));
    }

    @Test
    void listCookingLogsShouldReturnRecent() {
        var household = testHousehold();
        var recipe = testRecipe(household, "Spaghetti");
        var user = new UserAccount("sarah@example.com", "Sarah", "hashed");
        setId(user, UserAccount.class, UUID.randomUUID());
        var log = new CookingLog(recipe, household, LocalDate.of(2026, 4, 7), user);
        setId(log, CookingLog.class, UUID.randomUUID());

        when(cookingLogRepository.findByHouseholdIdOrderByCookedOnDesc(eq(HOUSEHOLD_ID), any()))
                .thenReturn(List.of(log));

        List<CookingLogResponse> result = planningService.listCookingLogs(HOUSEHOLD_ID, 30, 0);

        assertThat(result).hasSize(1);
        assertThat(result.getFirst().recipeName()).isEqualTo("Spaghetti");
    }

    // ── Plan not found / household mismatch ──

    @Test
    void getWeekPlanShouldThrowWhenPlanBelongsToDifferentHousehold() {
        var otherHousehold = new Household("Other family", null);
        setId(otherHousehold, Household.class, UUID.randomUUID());
        var plan = new WeekPlan(otherHousehold, WEEK_START);
        setId(plan, WeekPlan.class, UUID.randomUUID());

        // getWeekPlan uses findByHouseholdIdAndWeekStart so it won't find it for wrong household
        when(weekPlanRepository.findByHouseholdIdAndWeekStart(HOUSEHOLD_ID, WEEK_START))
                .thenReturn(Optional.empty());

        assertThatThrownBy(() -> planningService.getWeekPlan(HOUSEHOLD_ID, WEEK_START))
                .isInstanceOf(ResourceNotFoundException.class);
    }

    @Test
    void addSlotShouldThrowWhenPlanNotFound() {
        var planId = UUID.randomUUID();
        when(weekPlanRepository.findById(planId)).thenReturn(Optional.empty());

        assertThatThrownBy(() -> planningService.addSlot(HOUSEHOLD_ID, planId,
                new CreateSlotRequest(WEEK_START, UUID.randomUUID())))
                .isInstanceOf(ResourceNotFoundException.class);
    }

    @Test
    void addSlotShouldThrowWhenPlanHouseholdMismatch() {
        var otherHousehold = new Household("Other family", null);
        setId(otherHousehold, Household.class, UUID.randomUUID());
        var plan = new WeekPlan(otherHousehold, WEEK_START);
        setId(plan, WeekPlan.class, UUID.randomUUID());

        when(weekPlanRepository.findById(plan.getId())).thenReturn(Optional.of(plan));

        assertThatThrownBy(() -> planningService.addSlot(HOUSEHOLD_ID, plan.getId(),
                new CreateSlotRequest(WEEK_START, UUID.randomUUID())))
                .isInstanceOf(ResourceNotFoundException.class);
    }

    @Test
    void addSlotShouldThrowWhenRecipeNotFound() {
        var household = testHousehold();
        var plan = testWeekPlan(household);
        var recipeId = UUID.randomUUID();

        when(weekPlanRepository.findById(plan.getId())).thenReturn(Optional.of(plan));
        when(recipeRepository.findByIdAndHouseholdIdAndDeletedAtIsNull(recipeId, HOUSEHOLD_ID))
                .thenReturn(Optional.empty());

        assertThatThrownBy(() -> planningService.addSlot(HOUSEHOLD_ID, plan.getId(),
                new CreateSlotRequest(WEEK_START, recipeId)))
                .isInstanceOf(ResourceNotFoundException.class);
    }

    @Test
    void updateSlotShouldThrowWhenSlotNotFound() {
        var household = testHousehold();
        var plan = testWeekPlan(household);
        var slotId = UUID.randomUUID();

        when(weekPlanRepository.findById(plan.getId())).thenReturn(Optional.of(plan));
        when(weekPlanSlotRepository.findById(slotId)).thenReturn(Optional.empty());

        assertThatThrownBy(() -> planningService.updateSlot(HOUSEHOLD_ID, plan.getId(), slotId,
                new UpdateSlotRequest(UUID.randomUUID())))
                .isInstanceOf(ResourceNotFoundException.class);
    }

    @Test
    void deleteSlotShouldThrowWhenSlotNotFound() {
        var household = testHousehold();
        var plan = testWeekPlan(household);
        var slotId = UUID.randomUUID();

        when(weekPlanRepository.findById(plan.getId())).thenReturn(Optional.of(plan));
        when(weekPlanSlotRepository.findById(slotId)).thenReturn(Optional.empty());

        assertThatThrownBy(() -> planningService.deleteSlot(HOUSEHOLD_ID, plan.getId(), slotId))
                .isInstanceOf(ResourceNotFoundException.class);
    }

    @Test
    void confirmPlanShouldThrowWhenPlanNotFound() {
        var planId = UUID.randomUUID();
        when(weekPlanRepository.findById(planId)).thenReturn(Optional.empty());

        assertThatThrownBy(() -> planningService.confirmPlan(HOUSEHOLD_ID, planId))
                .isInstanceOf(ResourceNotFoundException.class);
    }

    // ── Cooking log edge cases ──

    @Test
    void createCookingLogShouldDefaultToTodayWhenCookedOnNull() {
        var household = testHousehold();
        var recipe = testRecipe(household, "Spaghetti");
        var user = new UserAccount("sarah@example.com", "Sarah", "hashed");
        setId(user, UserAccount.class, UUID.randomUUID());

        when(recipeRepository.findById(recipe.getId())).thenReturn(Optional.of(recipe));
        when(householdRepository.findById(HOUSEHOLD_ID)).thenReturn(Optional.of(household));
        when(userAccountRepository.findById(user.getId())).thenReturn(Optional.of(user));
        when(cookingLogRepository.save(any(CookingLog.class))).thenAnswer(i -> {
            CookingLog cl = i.getArgument(0);
            setId(cl, CookingLog.class, UUID.randomUUID());
            return cl;
        });

        CookingLogResponse result = planningService.createCookingLog(HOUSEHOLD_ID, user.getId(),
                new CreateCookingLogRequest(recipe.getId(), null));

        assertThat(result.cookedOn()).isEqualTo(LocalDate.now());
    }

    @Test
    void createCookingLogShouldThrowWhenRecipeNotFound() {
        var recipeId = UUID.randomUUID();
        when(recipeRepository.findById(recipeId)).thenReturn(Optional.empty());

        assertThatThrownBy(() -> planningService.createCookingLog(HOUSEHOLD_ID, UUID.randomUUID(),
                new CreateCookingLogRequest(recipeId, LocalDate.now())))
                .isInstanceOf(ResourceNotFoundException.class);
    }

    @Test
    void createCookingLogShouldThrowWhenHouseholdNotFound() {
        var household = testHousehold();
        var recipe = testRecipe(household, "Spaghetti");

        when(recipeRepository.findById(recipe.getId())).thenReturn(Optional.of(recipe));
        when(householdRepository.findById(HOUSEHOLD_ID)).thenReturn(Optional.empty());

        assertThatThrownBy(() -> planningService.createCookingLog(HOUSEHOLD_ID, UUID.randomUUID(),
                new CreateCookingLogRequest(recipe.getId(), LocalDate.now())))
                .isInstanceOf(ResourceNotFoundException.class);
    }

    @Test
    void createCookingLogShouldThrowWhenUserNotFound() {
        var household = testHousehold();
        var recipe = testRecipe(household, "Spaghetti");
        var userId = UUID.randomUUID();

        when(recipeRepository.findById(recipe.getId())).thenReturn(Optional.of(recipe));
        when(householdRepository.findById(HOUSEHOLD_ID)).thenReturn(Optional.of(household));
        when(userAccountRepository.findById(userId)).thenReturn(Optional.empty());

        assertThatThrownBy(() -> planningService.createCookingLog(HOUSEHOLD_ID, userId,
                new CreateCookingLogRequest(recipe.getId(), LocalDate.now())))
                .isInstanceOf(ResourceNotFoundException.class);
    }

    // ── Create week plan edge cases ──

    @Test
    void createWeekPlanShouldThrowWhenHouseholdNotFound() {
        when(weekPlanRepository.existsByHouseholdIdAndWeekStart(HOUSEHOLD_ID, WEEK_START)).thenReturn(false);
        when(householdRepository.findById(HOUSEHOLD_ID)).thenReturn(Optional.empty());

        assertThatThrownBy(() -> planningService.createWeekPlan(HOUSEHOLD_ID, WEEK_START))
                .isInstanceOf(ResourceNotFoundException.class);
    }

    // ── Variety preview ──

    @Test
    void getVarietyPreviewShouldReturnScoreDeltaForDifferentRecipe() {
        var household = testHousehold();
        var plan = testWeekPlan(household);
        var planId = plan.getId();

        // Plan already has one slot (Mon) with Spaghetti
        var existingRecipe = testRecipe(household, "Spaghetti");
        var slot = new WeekPlanSlot(plan, existingRecipe, WEEK_START);
        setId(slot, WeekPlanSlot.class, UUID.randomUUID());
        plan.getSlots().add(slot);

        // Candidate is Lachsfilet (different recipe, no shared tags/ingredients)
        var candidate = testRecipe(household, "Lachsfilet");
        var candidateId = candidate.getId();

        when(weekPlanRepository.findById(planId)).thenReturn(Optional.of(plan));
        when(recipeRepository.findByIdAndHouseholdIdAndDeletedAtIsNull(candidateId, HOUSEHOLD_ID))
                .thenReturn(Optional.of(candidate));
        when(varietyScoreConfigRepository.findByHouseholdId(HOUSEHOLD_ID)).thenReturn(Optional.empty());
        when(cookingLogRepository.findByHouseholdIdAndCookedOnAfter(eq(HOUSEHOLD_ID), any()))
                .thenReturn(List.of());

        var result = planningService.getVarietyPreview(HOUSEHOLD_ID, planId, candidateId, WEEK_START.plusDays(1));

        // 1 existing slot with no conflicts → currentScore = 10.0
        // Adding a different recipe with no tags/ingredients → projectedScore = 10.0, delta = 0
        assertThat(result.currentScore()).isEqualTo(10.0);
        assertThat(result.projectedScore()).isEqualTo(10.0);
        assertThat(result.scoreDelta()).isEqualTo(0.0);
    }

    @Test
    void getVarietyPreviewShouldReturnNegativeDeltaForDuplicateRecipe() {
        var household = testHousehold();
        var plan = testWeekPlan(household);
        var planId = plan.getId();

        // Plan already has Spaghetti on Mon
        var existingRecipe = testRecipe(household, "Spaghetti");
        var slot = new WeekPlanSlot(plan, existingRecipe, WEEK_START);
        setId(slot, WeekPlanSlot.class, UUID.randomUUID());
        plan.getSlots().add(slot);

        // Candidate is the same Spaghetti recipe → triggers duplicate penalty (wPlanDuplicate = 2.0)
        when(weekPlanRepository.findById(planId)).thenReturn(Optional.of(plan));
        when(recipeRepository.findByIdAndHouseholdIdAndDeletedAtIsNull(existingRecipe.getId(), HOUSEHOLD_ID))
                .thenReturn(Optional.of(existingRecipe));
        when(varietyScoreConfigRepository.findByHouseholdId(HOUSEHOLD_ID)).thenReturn(Optional.empty());
        when(cookingLogRepository.findByHouseholdIdAndCookedOnAfter(eq(HOUSEHOLD_ID), any()))
                .thenReturn(List.of());

        var result = planningService.getVarietyPreview(
                HOUSEHOLD_ID, planId, existingRecipe.getId(), WEEK_START.plusDays(1));

        // currentScore = 10.0 (1 slot, no conflicts)
        // projectedScore = 10.0 - 1 * 2.0 (duplicate penalty) = 8.0
        assertThat(result.currentScore()).isEqualTo(10.0);
        assertThat(result.projectedScore()).isEqualTo(8.0);
        assertThat(result.scoreDelta()).isEqualTo(-2.0);
    }

    @Test
    void getVarietyPreviewShouldThrowWhenPlanNotFound() {
        var planId = UUID.randomUUID();
        when(weekPlanRepository.findById(planId)).thenReturn(Optional.empty());

        assertThatThrownBy(() -> planningService.getVarietyPreview(
                HOUSEHOLD_ID, planId, UUID.randomUUID(), WEEK_START))
                .isInstanceOf(ResourceNotFoundException.class);
    }

    @Test
    void getVarietyPreviewShouldThrowWhenRecipeNotFound() {
        var household = testHousehold();
        var plan = testWeekPlan(household);
        var recipeId = UUID.randomUUID();

        when(weekPlanRepository.findById(plan.getId())).thenReturn(Optional.of(plan));
        when(recipeRepository.findByIdAndHouseholdIdAndDeletedAtIsNull(recipeId, HOUSEHOLD_ID))
                .thenReturn(Optional.empty());

        assertThatThrownBy(() -> planningService.getVarietyPreview(
                HOUSEHOLD_ID, plan.getId(), recipeId, WEEK_START))
                .isInstanceOf(ResourceNotFoundException.class);
    }
}