diff --git a/AGENTS.md b/AGENTS.md
index 26d90c3..9e71148 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -15,12 +15,11 @@ It describes what the project is, what is already implemented, and what still ne
   - `backend/`
   - `frontend/`
 
-## Current State (as of 2026-02-11)
+## Current State (as of 2026-02-12)
 
 - `README.md` already contains product specification in Slovak and English.
 - Backend DB migrations exist in `backend/src/Maintenance.php` up to version `7`.
-- Backend API routes are not implemented yet:
-  - `backend/src/API.php` extends `APIlite` but has no endpoints.
+- Backend API methods are implemented in `backend/src/API.php`.
 - Frontend is still template-level:
   - `frontend/src/App.vue` has placeholder content.
   - `frontend/src/router/index.ts` has empty `routes: []`.
@@ -34,6 +33,8 @@ It describes what the project is, what is already implemented, and what still ne
   - Supports `mysql` and `sqlite`
   - Loads override config files from `backend/config/*.php` (except the base file itself)
 - Migration logic: `backend/src/Maintenance.php`
+- API implementation: `backend/src/API.php`
+- DB table models: `backend/src/Models/*.php`
 
 ## Database Schema Snapshot
 
@@ -55,6 +56,51 @@ Migration creates these tables:
   - `diary_entry_id`, `diary_day_id`, `meal_type`, `meal_id`
   - unique: `(diary_day_id, meal_type)`
 
+## API Surface (Implemented)
+
+All actions are invoked through `backend/public/API.php` with `?action=<method_name>`.
+
+- Utility:
+  - `health`
+- Ingredients:
+  - `ingredientList(user_id, query = "", include_global = true)`
+  - `ingredientGet(user_id, ingredient_id)`
+  - `ingredientCreate(user_id, name, protein_g_100, carbs_g_100, sugar_g_100, fat_g_100, fiber_g_100 = 0, kcal_100 = 0)`
+  - `ingredientUpdate(user_id, ingredient_id, name, protein_g_100, carbs_g_100, sugar_g_100, fat_g_100, fiber_g_100 = 0, kcal_100 = 0)`
+  - `ingredientDelete(user_id, ingredient_id)`
+- Meals:
+  - `mealList(user_id, meal_type = "", with_items = false, with_totals = false)`
+  - `mealGet(user_id, meal_id, with_items = true, with_totals = true)`
+  - `mealCreate(user_id, name, meal_type)`
+  - `mealUpdate(user_id, meal_id, name, meal_type)`
+  - `mealDelete(user_id, meal_id)`
+- Meal items:
+  - `mealItemList(user_id, meal_id, with_calculated = true)`
+  - `mealItemAdd(user_id, meal_id, ingredient_id, grams, position = 1)`
+  - `mealItemUpdate(user_id, meal_item_id, ingredient_id, grams, position)`
+  - `mealItemDelete(user_id, meal_item_id)`
+  - `mealItemReorder(user_id, meal_id, ordered_item_ids)`
+- Calculations:
+  - `mealTotals(user_id, meal_id)`
+- Diary:
+  - `diaryDayGet(user_id, day_date, with_totals = true)`
+  - `diaryDaySetMeal(user_id, day_date, meal_type, meal_id)`
+  - `diaryDayUnsetMeal(user_id, day_date, meal_type)`
+  - `diaryRange(user_id, date_from, date_to)`
+
+## Behavior and Validation Rules
+
+- `meal_type` must be one of: `breakfast`, `lunch`, `dinner`.
+- Date params must use format `YYYY-MM-DD`.
+- `grams` must be `> 0`.
+- Nutrition input values are validated as non-negative.
+- If `kcal_100` is `0`, API computes kcal by formula:
+  - `protein*4 + carbs*4 + fat*9`
+- Ownership checks are enforced by `user_id`:
+  - meals and meal items must belong to the user
+  - ingredients can be user-owned or global (`user_id = null`) for read/select
+- API currently requires an existing `users` record for almost all actions.
+
 ## Known Pitfalls and Notes
 
 - The historical FK issue in `meal_items` should reference `meals(meal_id)`.  
@@ -62,6 +108,9 @@ Migration creates these tables:
 - If someone ran migrations before FK fix, old MySQL state may still be broken.  
   In that case reset affected table(s) or rebuild DB from clean state.
 - Some comments in `Maintenance.php` show encoding artifacts, but SQL structure is valid.
+- Authentication is not implemented yet; `user_id` is passed as an action parameter.
+- For `array` parameters (for example `ordered_item_ids`), APIlite expects JSON in request payload.
+- APIlite wraps responses with a nested `data` object. Keep this in mind on frontend parsing.
 
 ## Local Runbook
 
@@ -82,15 +131,15 @@ Frontend:
 
 ## Product Behavior Target (what to build next)
 
-- CRUD for ingredients with per-100g nutrition values.
-- CRUD for meals grouped by day part (`breakfast`, `lunch`, `dinner`).
-- Add meal items by ingredient + grams.
-- Compute per-item nutrition and calories from grams.
-- Compute totals for full meal.
-- Diary day view: assign one meal per day part and compute whole-day totals.
+- Implement auth and session handling (replace plain `user_id` input model).
+- Build frontend screens for ingredients, meals, meal item editor, diary day, diary range.
+- Connect frontend to implemented backend actions.
+- Add API tests for validation, ownership checks, and totals calculation consistency.
+- Add pagination/filter strategy where list endpoints grow.
 
 ## Practical Conventions
 
 - Keep IDs as `BIGINT UNSIGNED` and use `*_id` naming consistently.
 - Keep MySQL + SQLite compatibility in SQL where possible (project supports both).
 - When changing schema, always bump DB version in `Maintenance.php` with forward-only migration steps.
+- Keep API action names stable unless frontend is updated at the same time.
diff --git a/backend/src/API.php b/backend/src/API.php
index c71c5c1..7aced24 100644
--- a/backend/src/API.php
+++ b/backend/src/API.php
@@ -5,7 +5,843 @@ namespace TPsoft\Nutrio;
 require_once __DIR__.'/Init.php';
 
 use TPsoft\APIlite\APIlite;
+use TPsoft\Nutrio\Models\DiaryDays;
+use TPsoft\Nutrio\Models\DiaryEntries;
+use TPsoft\Nutrio\Models\Ingredients;
+use TPsoft\Nutrio\Models\MealItems;
+use TPsoft\Nutrio\Models\Meals;
+use TPsoft\Nutrio\Models\Options;
+use TPsoft\Nutrio\Models\Users;
 
 class API extends APIlite {
 
+	private ?Users $usersModel = null;
+	private ?Ingredients $ingredientsModel = null;
+	private ?Meals $mealsModel = null;
+	private ?MealItems $mealItemsModel = null;
+	private ?DiaryDays $diaryDaysModel = null;
+	private ?DiaryEntries $diaryEntriesModel = null;
+	private ?Options $optionsModel = null;
+
+	public function health(): array
+	{
+		$dbVersion = null;
+		$versionRow = $this->options()->option('version');
+		if (is_array($versionRow) && isset($versionRow['value'])) {
+			$dbVersion = (string) $versionRow['value'];
+		}
+		return array(
+			'service' => 'Nutrio API',
+			'timestamp' => date('c'),
+			'db_type' => $this->users()->getDBtype(),
+			'db_version' => $dbVersion
+		);
+	}
+
+	public function ingredientList(int $user_id, string $query = '', bool $include_global = true): array
+	{
+		$this->assertUserExists($user_id);
+		$search = array(
+			'user_id' => $include_global ? array($user_id, null) : $user_id
+		);
+		$query = trim($query);
+		if (strlen($query) > 0) {
+			$search['name'] = '%' . $query . '%';
+		}
+		$list = $this->ingredients()->getList($search);
+		$list = is_array($list) ? $list : array();
+		$result = array();
+		foreach ($list as $row) {
+			$result[] = $this->mapIngredient($row);
+		}
+		return $result;
+	}
+
+	public function ingredientGet(int $user_id, int $ingredient_id): array
+	{
+		$this->assertUserExists($user_id);
+		return $this->mapIngredient($this->getIngredientAccessible($user_id, $ingredient_id));
+	}
+
+	public function ingredientCreate(
+		int $user_id,
+		string $name,
+		float $protein_g_100,
+		float $carbs_g_100,
+		float $sugar_g_100,
+		float $fat_g_100,
+		float $fiber_g_100 = 0,
+		float $kcal_100 = 0
+	): array {
+		$this->assertUserExists($user_id);
+		$name = $this->normalizeName($name);
+		$this->assertNonNegative('protein_g_100', $protein_g_100);
+		$this->assertNonNegative('carbs_g_100', $carbs_g_100);
+		$this->assertNonNegative('sugar_g_100', $sugar_g_100);
+		$this->assertNonNegative('fat_g_100', $fat_g_100);
+		$this->assertNonNegative('fiber_g_100', $fiber_g_100);
+		if ($kcal_100 < 0) {
+			throw new \Exception('kcal_100 cannot be negative');
+		}
+		if ($kcal_100 == 0) {
+			$kcal_100 = $this->computeKcal100($protein_g_100, $carbs_g_100, $fat_g_100);
+		}
+		$ingredientId = $this->ingredients()->ingredientSave(array(
+			'user_id' => $user_id,
+			'name' => $name,
+			'protein_g_100' => $this->round2($protein_g_100),
+			'carbs_g_100' => $this->round2($carbs_g_100),
+			'sugar_g_100' => $this->round2($sugar_g_100),
+			'fat_g_100' => $this->round2($fat_g_100),
+			'fiber_g_100' => $this->round2($fiber_g_100),
+			'kcal_100' => $this->round2($kcal_100),
+			'created_at' => '`NOW`'
+		));
+		if ($ingredientId === false) {
+			throw new \Exception('Failed to create ingredient');
+		}
+		$created = $this->ingredients()->ingredient((int) $ingredientId);
+		if (!is_array($created)) {
+			throw new \Exception('Failed to load created ingredient');
+		}
+		return $this->mapIngredient($created);
+	}
+
+	public function ingredientUpdate(
+		int $user_id,
+		int $ingredient_id,
+		string $name,
+		float $protein_g_100,
+		float $carbs_g_100,
+		float $sugar_g_100,
+		float $fat_g_100,
+		float $fiber_g_100 = 0,
+		float $kcal_100 = 0
+	): array {
+		$this->assertUserExists($user_id);
+		$this->getIngredientOwned($user_id, $ingredient_id);
+		$name = $this->normalizeName($name);
+		$this->assertNonNegative('protein_g_100', $protein_g_100);
+		$this->assertNonNegative('carbs_g_100', $carbs_g_100);
+		$this->assertNonNegative('sugar_g_100', $sugar_g_100);
+		$this->assertNonNegative('fat_g_100', $fat_g_100);
+		$this->assertNonNegative('fiber_g_100', $fiber_g_100);
+		if ($kcal_100 < 0) {
+			throw new \Exception('kcal_100 cannot be negative');
+		}
+		if ($kcal_100 == 0) {
+			$kcal_100 = $this->computeKcal100($protein_g_100, $carbs_g_100, $fat_g_100);
+		}
+		$updated = $this->ingredients()->ingredient($ingredient_id, array(
+			'name' => $name,
+			'protein_g_100' => $this->round2($protein_g_100),
+			'carbs_g_100' => $this->round2($carbs_g_100),
+			'sugar_g_100' => $this->round2($sugar_g_100),
+			'fat_g_100' => $this->round2($fat_g_100),
+			'fiber_g_100' => $this->round2($fiber_g_100),
+			'kcal_100' => $this->round2($kcal_100)
+		));
+		if ($updated === false) {
+			throw new \Exception('Failed to update ingredient');
+		}
+		$row = $this->ingredients()->ingredient($ingredient_id);
+		if (!is_array($row)) {
+			throw new \Exception('Failed to load updated ingredient');
+		}
+		return $this->mapIngredient($row);
+	}
+
+	public function ingredientDelete(int $user_id, int $ingredient_id): array
+	{
+		$this->assertUserExists($user_id);
+		$this->getIngredientOwned($user_id, $ingredient_id);
+		$deleted = $this->ingredients()->ingredient($ingredient_id, null);
+		if ($deleted === false) {
+			throw new \Exception('Failed to delete ingredient');
+		}
+		return array(
+			'deleted' => true,
+			'ingredient_id' => $ingredient_id
+		);
+	}
+
+	public function mealList(int $user_id, string $meal_type = '', bool $with_items = false, bool $with_totals = false): array
+	{
+		$this->assertUserExists($user_id);
+		$search = array('user_id' => $user_id);
+		$meal_type = trim($meal_type);
+		if (strlen($meal_type) > 0) {
+			$this->assertMealType($meal_type);
+			$search['meal_type'] = $meal_type;
+		}
+		$rows = $this->meals()->getList($search);
+		$rows = is_array($rows) ? $rows : array();
+		$result = array();
+		foreach ($rows as $row) {
+			$meal = $this->mapMeal($row);
+			$calculatedItems = null;
+			if ($with_items) {
+				$calculatedItems = $this->buildMealItems((int) $meal['meal_id'], true);
+				$meal['items'] = $calculatedItems;
+			}
+			if ($with_totals) {
+				if (is_array($calculatedItems)) {
+					$meal['totals'] = $this->totalsFromCalculatedItems($calculatedItems);
+				} else {
+					$meal['totals'] = $this->calculateMealTotals((int) $meal['meal_id']);
+				}
+			}
+			$result[] = $meal;
+		}
+		return $result;
+	}
+
+	public function mealGet(int $user_id, int $meal_id, bool $with_items = true, bool $with_totals = true): array
+	{
+		$this->assertUserExists($user_id);
+		$meal = $this->mapMeal($this->getMealOwned($user_id, $meal_id));
+		$calculatedItems = null;
+		if ($with_items) {
+			$calculatedItems = $this->buildMealItems($meal_id, true);
+			$meal['items'] = $calculatedItems;
+		}
+		if ($with_totals) {
+			if (is_array($calculatedItems)) {
+				$meal['totals'] = $this->totalsFromCalculatedItems($calculatedItems);
+			} else {
+				$meal['totals'] = $this->calculateMealTotals($meal_id);
+			}
+		}
+		return $meal;
+	}
+
+	public function mealCreate(int $user_id, string $name, string $meal_type): array
+	{
+		$this->assertUserExists($user_id);
+		$name = $this->normalizeName($name);
+		$this->assertMealType($meal_type);
+		$mealId = $this->meals()->mealSave(array(
+			'user_id' => $user_id,
+			'name' => $name,
+			'meal_type' => $meal_type,
+			'created_at' => '`NOW`'
+		));
+		if ($mealId === false) {
+			throw new \Exception('Failed to create meal');
+		}
+		return $this->mealGet($user_id, (int) $mealId, false, false);
+	}
+
+	public function mealUpdate(int $user_id, int $meal_id, string $name, string $meal_type): array
+	{
+		$this->assertUserExists($user_id);
+		$this->getMealOwned($user_id, $meal_id);
+		$name = $this->normalizeName($name);
+		$this->assertMealType($meal_type);
+		$updated = $this->meals()->meal($meal_id, array(
+			'name' => $name,
+			'meal_type' => $meal_type
+		));
+		if ($updated === false) {
+			throw new \Exception('Failed to update meal');
+		}
+		return $this->mealGet($user_id, $meal_id, false, false);
+	}
+
+	public function mealDelete(int $user_id, int $meal_id): array
+	{
+		$this->assertUserExists($user_id);
+		$this->getMealOwned($user_id, $meal_id);
+		$deleted = $this->meals()->meal($meal_id, null);
+		if ($deleted === false) {
+			throw new \Exception('Failed to delete meal');
+		}
+		return array(
+			'deleted' => true,
+			'meal_id' => $meal_id
+		);
+	}
+
+	public function mealItemList(int $user_id, int $meal_id, bool $with_calculated = true): array
+	{
+		$this->assertUserExists($user_id);
+		$this->getMealOwned($user_id, $meal_id);
+		return array(
+			'meal_id' => $meal_id,
+			'items' => $this->buildMealItems($meal_id, $with_calculated)
+		);
+	}
+
+	public function mealItemAdd(int $user_id, int $meal_id, int $ingredient_id, float $grams, int $position = 1): array
+	{
+		$this->assertUserExists($user_id);
+		$this->getMealOwned($user_id, $meal_id);
+		$this->assertPositive('grams', $grams);
+		if ($position < 1) {
+			throw new \Exception('position must be >= 1');
+		}
+		$this->getIngredientAccessible($user_id, $ingredient_id);
+		$mealItemId = $this->mealItems()->mealItemSave(array(
+			'meal_id' => $meal_id,
+			'ingredient_id' => $ingredient_id,
+			'grams' => $this->round2($grams),
+			'position' => $position
+		));
+		if ($mealItemId === false) {
+			throw new \Exception('Failed to add meal item');
+		}
+		$item = $this->getMealItemOwned($user_id, (int) $mealItemId);
+		return $this->enrichMealItem($item);
+	}
+
+	public function mealItemUpdate(int $user_id, int $meal_item_id, int $ingredient_id, float $grams, int $position): array
+	{
+		$this->assertUserExists($user_id);
+		$item = $this->getMealItemOwned($user_id, $meal_item_id);
+		$this->assertPositive('grams', $grams);
+		if ($position < 1) {
+			throw new \Exception('position must be >= 1');
+		}
+		$this->getIngredientAccessible($user_id, $ingredient_id);
+		$updated = $this->mealItems()->mealItem($meal_item_id, array(
+			'ingredient_id' => $ingredient_id,
+			'grams' => $this->round2($grams),
+			'position' => $position
+		));
+		if ($updated === false) {
+			throw new \Exception('Failed to update meal item');
+		}
+		$item = $this->getMealItemOwned($user_id, (int) $item['meal_item_id']);
+		return $this->enrichMealItem($item);
+	}
+
+	public function mealItemDelete(int $user_id, int $meal_item_id): array
+	{
+		$this->assertUserExists($user_id);
+		$item = $this->getMealItemOwned($user_id, $meal_item_id);
+		$deleted = $this->mealItems()->mealItem($meal_item_id, null);
+		if ($deleted === false) {
+			throw new \Exception('Failed to delete meal item');
+		}
+		return array(
+			'deleted' => true,
+			'meal_item_id' => $meal_item_id,
+			'meal_id' => (int) $item['meal_id']
+		);
+	}
+
+	public function mealItemReorder(int $user_id, int $meal_id, array $ordered_item_ids): array
+	{
+		$this->assertUserExists($user_id);
+		$this->getMealOwned($user_id, $meal_id);
+		if (count($ordered_item_ids) <= 0) {
+			throw new \Exception('ordered_item_ids cannot be empty');
+		}
+		$currentItems = $this->buildMealItems($meal_id, false);
+		$currentIds = array();
+		foreach ($currentItems as $item) {
+			$currentIds[] = (int) $item['meal_item_id'];
+		}
+		$orderedIds = array_values(array_map('intval', $ordered_item_ids));
+		sort($currentIds);
+		$checkIds = $orderedIds;
+		sort($checkIds);
+		if ($currentIds !== $checkIds) {
+			throw new \Exception('ordered_item_ids must match all meal item ids exactly');
+		}
+		foreach ($orderedIds as $index => $mealItemId) {
+			$ok = $this->mealItems()->mealItem($mealItemId, array('position' => $index + 1));
+			if ($ok === false) {
+				throw new \Exception('Failed to reorder meal items');
+			}
+		}
+		return array(
+			'meal_id' => $meal_id,
+			'items' => $this->buildMealItems($meal_id, true)
+		);
+	}
+
+	public function mealTotals(int $user_id, int $meal_id): array
+	{
+		$this->assertUserExists($user_id);
+		$this->getMealOwned($user_id, $meal_id);
+		return array(
+			'meal_id' => $meal_id,
+			'totals' => $this->calculateMealTotals($meal_id)
+		);
+	}
+
+	public function diaryDayGet(int $user_id, string $day_date, bool $with_totals = true): array
+	{
+		$this->assertUserExists($user_id);
+		$this->assertDate($day_date);
+		return $this->buildDiaryDay($user_id, $day_date, $with_totals);
+	}
+
+	public function diaryDaySetMeal(int $user_id, string $day_date, string $meal_type, int $meal_id): array
+	{
+		$this->assertUserExists($user_id);
+		$this->assertDate($day_date);
+		$this->assertMealType($meal_type);
+		$meal = $this->getMealOwned($user_id, $meal_id);
+		if ($meal['meal_type'] !== $meal_type) {
+			throw new \Exception('meal_type does not match selected meal');
+		}
+		$day = $this->ensureDiaryDay($user_id, $day_date);
+		$existing = $this->diaryEntries()->search('diaryEntries')
+			->where(array(
+				'diary_day_id' => (int) $day['diary_day_id'],
+				'meal_type' => $meal_type
+			))
+			->toArrayFirst();
+		if (is_array($existing) && isset($existing['diary_entry_id'])) {
+			$updated = $this->diaryEntries()->diaryEntry((int) $existing['diary_entry_id'], array(
+				'meal_id' => $meal_id
+			));
+			if ($updated === false) {
+				throw new \Exception('Failed to update diary entry');
+			}
+		} else {
+			$inserted = $this->diaryEntries()->diaryEntrySave(array(
+				'diary_day_id' => (int) $day['diary_day_id'],
+				'meal_type' => $meal_type,
+				'meal_id' => $meal_id,
+				'created_at' => '`NOW`'
+			));
+			if ($inserted === false) {
+				throw new \Exception('Failed to create diary entry');
+			}
+		}
+		return $this->buildDiaryDay($user_id, $day_date, true);
+	}
+
+	public function diaryDayUnsetMeal(int $user_id, string $day_date, string $meal_type): array
+	{
+		$this->assertUserExists($user_id);
+		$this->assertDate($day_date);
+		$this->assertMealType($meal_type);
+		$day = $this->getDiaryDay($user_id, $day_date);
+		if ($day === false) {
+			return $this->buildDiaryDay($user_id, $day_date, true);
+		}
+		$existing = $this->diaryEntries()->search('diaryEntries')
+			->where(array(
+				'diary_day_id' => (int) $day['diary_day_id'],
+				'meal_type' => $meal_type
+			))
+			->toArrayFirst();
+		if (is_array($existing) && isset($existing['diary_entry_id'])) {
+			$deleted = $this->diaryEntries()->diaryEntry((int) $existing['diary_entry_id'], null);
+			if ($deleted === false) {
+				throw new \Exception('Failed to delete diary entry');
+			}
+		}
+		return $this->buildDiaryDay($user_id, $day_date, true);
+	}
+
+	public function diaryRange(int $user_id, string $date_from, string $date_to): array
+	{
+		$this->assertUserExists($user_id);
+		$this->assertDate($date_from);
+		$this->assertDate($date_to);
+		if ($date_from > $date_to) {
+			throw new \Exception('date_from must be before or equal to date_to');
+		}
+		$rows = $this->diaryDays()->search('diaryDays')
+			->where(array('user_id' => $user_id))
+			->where(array('day_date' => '>=' . $date_from))
+			->where(array('day_date' => '<=' . $date_to))
+			->order(array('day_date' => 'ASC'))
+			->toArray();
+		$rows = is_array($rows) ? $rows : array();
+		$days = array();
+		$totals = $this->emptyTotals();
+		foreach ($rows as $row) {
+			$day = $this->buildDiaryDay($user_id, (string) $row['day_date'], true);
+			$days[] = $day;
+			if (isset($day['totals']) && is_array($day['totals'])) {
+				$totals = $this->addTotals($totals, $day['totals']);
+			}
+		}
+		return array(
+			'user_id' => $user_id,
+			'date_from' => $date_from,
+			'date_to' => $date_to,
+			'days' => $days,
+			'totals' => $totals
+		);
+	}
+
+	private function users(): Users
+	{
+		if ($this->usersModel === null) {
+			$this->usersModel = new Users();
+		}
+		return $this->usersModel;
+	}
+
+	private function ingredients(): Ingredients
+	{
+		if ($this->ingredientsModel === null) {
+			$this->ingredientsModel = new Ingredients();
+		}
+		return $this->ingredientsModel;
+	}
+
+	private function meals(): Meals
+	{
+		if ($this->mealsModel === null) {
+			$this->mealsModel = new Meals();
+		}
+		return $this->mealsModel;
+	}
+
+	private function mealItems(): MealItems
+	{
+		if ($this->mealItemsModel === null) {
+			$this->mealItemsModel = new MealItems();
+		}
+		return $this->mealItemsModel;
+	}
+
+	private function diaryDays(): DiaryDays
+	{
+		if ($this->diaryDaysModel === null) {
+			$this->diaryDaysModel = new DiaryDays();
+		}
+		return $this->diaryDaysModel;
+	}
+
+	private function diaryEntries(): DiaryEntries
+	{
+		if ($this->diaryEntriesModel === null) {
+			$this->diaryEntriesModel = new DiaryEntries();
+		}
+		return $this->diaryEntriesModel;
+	}
+
+	private function options(): Options
+	{
+		if ($this->optionsModel === null) {
+			$this->optionsModel = new Options();
+		}
+		return $this->optionsModel;
+	}
+
+	private function assertUserExists(int $user_id): void
+	{
+		if ($user_id <= 0) {
+			throw new \Exception('user_id must be > 0');
+		}
+		if (!$this->users()->exist($user_id)) {
+			throw new \Exception('User not found');
+		}
+	}
+
+	private function assertMealType(string $meal_type): void
+	{
+		$allowed = array('breakfast', 'lunch', 'dinner');
+		if (!in_array($meal_type, $allowed, true)) {
+			throw new \Exception('Invalid meal_type');
+		}
+	}
+
+	private function assertDate(string $day_date): void
+	{
+		$dt = \DateTime::createFromFormat('Y-m-d', $day_date);
+		if (!$dt || $dt->format('Y-m-d') !== $day_date) {
+			throw new \Exception('Invalid date format, expected YYYY-MM-DD');
+		}
+	}
+
+	private function assertNonNegative(string $name, float $value): void
+	{
+		if ($value < 0) {
+			throw new \Exception($name . ' cannot be negative');
+		}
+	}
+
+	private function assertPositive(string $name, float $value): void
+	{
+		if ($value <= 0) {
+			throw new \Exception($name . ' must be > 0');
+		}
+	}
+
+	private function normalizeName(string $name): string
+	{
+		$name = trim($name);
+		if (strlen($name) <= 0) {
+			throw new \Exception('name is required');
+		}
+		if (strlen($name) > 255) {
+			throw new \Exception('name is too long');
+		}
+		return $name;
+	}
+
+	private function round2(float $value): float
+	{
+		return round($value, 2);
+	}
+
+	private function computeKcal100(float $protein_g_100, float $carbs_g_100, float $fat_g_100): float
+	{
+		return $this->round2($protein_g_100 * 4 + $carbs_g_100 * 4 + $fat_g_100 * 9);
+	}
+
+	private function getMealOwned(int $user_id, int $meal_id): array
+	{
+		$meal = $this->meals()->meal($meal_id);
+		if (!is_array($meal)) {
+			throw new \Exception('Meal not found');
+		}
+		if ((int) $meal['user_id'] !== $user_id) {
+			throw new \Exception('Meal does not belong to user');
+		}
+		return $meal;
+	}
+
+	private function getIngredientAccessible(int $user_id, int $ingredient_id): array
+	{
+		$ingredient = $this->ingredients()->ingredient($ingredient_id);
+		if (!is_array($ingredient)) {
+			throw new \Exception('Ingredient not found');
+		}
+		if (!is_null($ingredient['user_id']) && (int) $ingredient['user_id'] !== $user_id) {
+			throw new \Exception('Ingredient is not accessible for user');
+		}
+		return $ingredient;
+	}
+
+	private function getIngredientOwned(int $user_id, int $ingredient_id): array
+	{
+		$ingredient = $this->ingredients()->ingredient($ingredient_id);
+		if (!is_array($ingredient)) {
+			throw new \Exception('Ingredient not found');
+		}
+		if (is_null($ingredient['user_id']) || (int) $ingredient['user_id'] !== $user_id) {
+			throw new \Exception('Ingredient does not belong to user');
+		}
+		return $ingredient;
+	}
+
+	private function getMealItemOwned(int $user_id, int $meal_item_id): array
+	{
+		$item = $this->mealItems()->mealItem($meal_item_id);
+		if (!is_array($item)) {
+			throw new \Exception('Meal item not found');
+		}
+		$this->getMealOwned($user_id, (int) $item['meal_id']);
+		return $this->mapMealItem($item);
+	}
+
+	private function buildMealItems(int $meal_id, bool $with_calculated = true): array
+	{
+		$rows = $this->mealItems()->search('mealItems')
+			->where(array('meal_id' => $meal_id))
+			->order(array('position' => 'ASC', 'meal_item_id' => 'ASC'))
+			->toArray();
+		$rows = is_array($rows) ? $rows : array();
+		$result = array();
+		foreach ($rows as $row) {
+			$item = $this->mapMealItem($row);
+			if ($with_calculated) {
+				$item = $this->enrichMealItem($item);
+			}
+			$result[] = $item;
+		}
+		return $result;
+	}
+
+	private function enrichMealItem(array $item): array
+	{
+		$ingredient = $this->ingredients()->ingredient((int) $item['ingredient_id']);
+		if (!is_array($ingredient)) {
+			throw new \Exception('Ingredient for meal item was not found');
+		}
+		$ingredient = $this->mapIngredient($ingredient);
+		$factor = ((float) $item['grams']) / 100;
+		$kcal100 = (float) $ingredient['kcal_100'];
+		if ($kcal100 <= 0) {
+			$kcal100 = $this->computeKcal100(
+				(float) $ingredient['protein_g_100'],
+				(float) $ingredient['carbs_g_100'],
+				(float) $ingredient['fat_g_100']
+			);
+		}
+		$item['ingredient'] = $ingredient;
+		$item['nutrition'] = array(
+			'protein_g' => $this->round2(((float) $ingredient['protein_g_100']) * $factor),
+			'carbs_g' => $this->round2(((float) $ingredient['carbs_g_100']) * $factor),
+			'sugar_g' => $this->round2(((float) $ingredient['sugar_g_100']) * $factor),
+			'fat_g' => $this->round2(((float) $ingredient['fat_g_100']) * $factor),
+			'fiber_g' => $this->round2(((float) $ingredient['fiber_g_100']) * $factor),
+			'kcal' => $this->round2($kcal100 * $factor)
+		);
+		return $item;
+	}
+
+	private function calculateMealTotals(int $meal_id): array
+	{
+		$items = $this->buildMealItems($meal_id, true);
+		return $this->totalsFromCalculatedItems($items);
+	}
+
+	private function totalsFromCalculatedItems(array $items): array
+	{
+		$totals = $this->emptyTotals();
+		foreach ($items as $item) {
+			if (!isset($item['nutrition']) || !is_array($item['nutrition'])) {
+				continue;
+			}
+			$totals = $this->addTotals($totals, $item['nutrition']);
+		}
+		return $totals;
+	}
+
+	private function emptyTotals(): array
+	{
+		return array(
+			'protein_g' => 0.0,
+			'carbs_g' => 0.0,
+			'sugar_g' => 0.0,
+			'fat_g' => 0.0,
+			'fiber_g' => 0.0,
+			'kcal' => 0.0
+		);
+	}
+
+	private function addTotals(array $base, array $add): array
+	{
+		foreach ($base as $key => $value) {
+			$base[$key] = $this->round2((float) $value + (float) ($add[$key] ?? 0));
+		}
+		return $base;
+	}
+
+	private function getDiaryDay(int $user_id, string $day_date): array|false
+	{
+		$rows = $this->diaryDays()->getList(array(
+			'user_id' => $user_id,
+			'day_date' => $day_date
+		));
+		if (!is_array($rows) || count($rows) <= 0) {
+			return false;
+		}
+		return $rows[0];
+	}
+
+	private function ensureDiaryDay(int $user_id, string $day_date): array
+	{
+		$day = $this->getDiaryDay($user_id, $day_date);
+		if (is_array($day)) {
+			return $this->mapDiaryDay($day);
+		}
+		$dayId = $this->diaryDays()->diaryDaySave(array(
+			'user_id' => $user_id,
+			'day_date' => $day_date,
+			'created_at' => '`NOW`'
+		));
+		if ($dayId === false) {
+			throw new \Exception('Failed to create diary day');
+		}
+		$created = $this->diaryDays()->diaryDay((int) $dayId);
+		if (!is_array($created)) {
+			throw new \Exception('Failed to load created diary day');
+		}
+		return $this->mapDiaryDay($created);
+	}
+
+	private function buildDiaryDay(int $user_id, string $day_date, bool $with_totals): array
+	{
+		$day = $this->getDiaryDay($user_id, $day_date);
+		if (!is_array($day)) {
+			$ret = array(
+				'user_id' => $user_id,
+				'day_date' => $day_date,
+				'diary_day_id' => null,
+				'entries' => array()
+			);
+			if ($with_totals) {
+				$ret['totals'] = $this->emptyTotals();
+			}
+			return $ret;
+		}
+		$day = $this->mapDiaryDay($day);
+		$entriesRows = $this->diaryEntries()->search('diaryEntries')
+			->where(array('diary_day_id' => (int) $day['diary_day_id']))
+			->order(array('diary_entry_id' => 'ASC'))
+			->toArray();
+		$entriesRows = is_array($entriesRows) ? $entriesRows : array();
+		$entries = array();
+		$totals = $this->emptyTotals();
+		foreach ($entriesRows as $row) {
+			$entry = $this->mapDiaryEntry($row);
+			$meal = $this->mapMeal($this->getMealOwned($user_id, (int) $entry['meal_id']));
+			$entry['meal'] = $meal;
+			if ($with_totals) {
+				$mealTotals = $this->calculateMealTotals((int) $entry['meal_id']);
+				$entry['meal_totals'] = $mealTotals;
+				$totals = $this->addTotals($totals, $mealTotals);
+			}
+			$entries[] = $entry;
+		}
+		$ret = array(
+			'user_id' => $user_id,
+			'day_date' => $day_date,
+			'diary_day_id' => (int) $day['diary_day_id'],
+			'entries' => $entries
+		);
+		if ($with_totals) {
+			$ret['totals'] = $totals;
+		}
+		return $ret;
+	}
+
+	private function mapIngredient(array $row): array
+	{
+		$row['ingredient_id'] = (int) $row['ingredient_id'];
+		$row['user_id'] = is_null($row['user_id']) ? null : (int) $row['user_id'];
+		$row['protein_g_100'] = $this->round2((float) $row['protein_g_100']);
+		$row['carbs_g_100'] = $this->round2((float) $row['carbs_g_100']);
+		$row['sugar_g_100'] = $this->round2((float) $row['sugar_g_100']);
+		$row['fat_g_100'] = $this->round2((float) $row['fat_g_100']);
+		$row['fiber_g_100'] = $this->round2((float) $row['fiber_g_100']);
+		$row['kcal_100'] = $this->round2((float) $row['kcal_100']);
+		return $row;
+	}
+
+	private function mapMeal(array $row): array
+	{
+		$row['meal_id'] = (int) $row['meal_id'];
+		$row['user_id'] = (int) $row['user_id'];
+		return $row;
+	}
+
+	private function mapMealItem(array $row): array
+	{
+		$row['meal_item_id'] = (int) $row['meal_item_id'];
+		$row['meal_id'] = (int) $row['meal_id'];
+		$row['ingredient_id'] = (int) $row['ingredient_id'];
+		$row['grams'] = $this->round2((float) $row['grams']);
+		$row['position'] = (int) $row['position'];
+		return $row;
+	}
+
+	private function mapDiaryDay(array $row): array
+	{
+		$row['diary_day_id'] = (int) $row['diary_day_id'];
+		$row['user_id'] = (int) $row['user_id'];
+		return $row;
+	}
+
+	private function mapDiaryEntry(array $row): array
+	{
+		$row['diary_entry_id'] = (int) $row['diary_entry_id'];
+		$row['diary_day_id'] = (int) $row['diary_day_id'];
+		$row['meal_id'] = (int) $row['meal_id'];
+		return $row;
+	}
+
 }