<?php

	namespace vlw\WP\Posts\Taxonomy;

	use Exception;
	use vlw\Scaffold\Database\Model;

	use vlw\WP\Database;
	use vlw\WP\Posts\Post;
	use vlw\WP\Tables\Terms;
	use vlw\WP\Posts\Taxonomy\Taxonomy;
	use vlw\WP\Tables\TermRelationships;
	use function vlw\WP\Support\slugify;

	require_once dirname(__DIR__, 1) . "/Post.php";
	require_once dirname(__DIR__, 2) . "/Tables/Terms.php";
	require_once dirname(__DIR__, 2) . "/Support/Slugify.php";
	require_once dirname(__DIR__, 2) . "/Tables/TermRelationships.php";

	class Term extends Model {
		/**
		 * Returns a Term by a name
		 *
		 * @param string $name
		 * @return static|null
		 */
		public static function from_name(string $name): ?static {
			$query = Database::current()
				->from(Database::get_table(Terms::TABLE_NAME))
				->where([Terms::NAME->value => $name])
				->limit(1)
				->select(Terms::TERM_ID->value);

			return $query->num_rows === 1 ? new static($query->fetch_assoc()[Terms::TERM_ID->value]) : null;
		}

		/**
		 * Returns an array of all Terms associated with a Post
		 *
		 * @param Post $post
		 * @return array
		 */
		public static function from_post(Post $post): array {
			$query = Database::current()
				->from(Database::get_table(TermRelationships::TABLE_NAME))
				->where([TermRelationships::OBJECT_ID->value => $post->id])
				->select(TermRelationships::TERM_TAXONOMY_ID->value);

			return array_map(fn(array $post_meta): static => new static($post_meta[TermRelationships::TERM_TAXONOMY_ID->value]), $query->fetch_all(MYSQLI_ASSOC));
		}

		/**
		 * Create a new post meta field for a given post
		 *
		 * @param string $title Post title
		 * @param string $type Post type
		 * @return static
		 */
		public static function new(string $name, ?string $slug = null): static {
			// Current auto increment value will be the id for this entity
			$id = Database::current()->latest(Terms::TABLE_NAME);

			$values = [
				Terms::TERM_ID->value    => null,
				Terms::NAME->value       => $name,
				Terms::SLUG->value       => $slug ? $slug : slugify($name),
				Terms::TERM_GROUP->value => 0
			];

			if (!parent::create(Database::get_table(Terms::TABLE_NAME), $values)) {
				throw new Exception("Failed to create database entity");
			}

			return new static($id);
		}

		public function __construct(public readonly int $id) {
			parent::__construct(
				Database::get_table(Terms::TABLE_NAME),
				Terms::values(),
				[Terms::TERM_ID->value => $id]
			);
		}

		public string $name {
			get                => $this->get(Terms::NAME->value);
			set (string $name) => $this->set(Terms::NAME->value, $name);
		}

		public string $slug {
			get                => $this->get(Terms::SLUG->value);
			set (string $slug) => $this->set(Terms::SLUG->value, $slug);
		}

		public int $term_group {
			get                   => $this->get(Terms::TERM_GROUP->value);
			set (int $term_group) => $this->set(Terms::TERM_GROUP->value, $term_group);
		}

		/**
		 * Returns an array of Taxonomies that implement this Term
		 *
		 * @return array
		 */
		public function taxonomies(): array {
			return Taxonomy::from_term($this);
		}

		/**
		 * Add this Term to a target Post
		 *
		 * @param Post $post
		 * @return void
		 */
		public function add_to_post(Post $post): void {
			// Bail out if this term has already been added to the target Post
			if ($this->post_has_term($post)) {
				return;
			}

			$query = Database::current()
				->from(Database::get_table(TermRelationships::TABLE_NAME))
				->insert([
					TermRelationships::OBJECT_ID->value        => $post->id,
					TermRelationships::TERM_TAXONOMY_ID->value => $this->id,
					TermRelationships::TERM_ORDER->value       => 0
				]);

			if ($query === false) {
				throw new Exception("Failed to create database entity");
			}

			// Increase the post count for each Taxonomy implementing this Term
			foreach ($this->taxonomies() as $taxonomy) {
				$taxonomy->count++;
			}
		}

		/**
		 * Remove this Term from a target Post
		 *
		 * @param Post $post
		 * @return void
		 */
		public function remove_from_post(Post $post): void {
			// Bail out if this Term is not set on the target Post
			if (!$this->post_has_term($post)) {
				return;
			}

			$query = Database::current()
				->from(Database::get_table(TermRelationships::TABLE_NAME))
				->delete([
					TermRelationships::OBJECT_ID->value        => $post->id,
					TermRelationships::TERM_TAXONOMY_ID->value => $this->id
				]);

			if ($query === false) {
				throw new Exception("Failed to create database entity");
			}

			// Decrease the post count for each Taxonomy implementing this Term
			foreach ($this->taxonomies() as $taxonomy) {
				$taxonomy->count--;
			}
		}

		/**
		 * Returns true if a given Post has this Term
		 *
		 * @param Post $post
		 * @return bool
		 */
		private function post_has_term(Post $post): bool {
			return in_array($this->id, array_column(self::from_post($post), "id"));
		}
	}