<?php

namespace Models;

use Core\Model;
use PDO;

class TagModel extends Model
{
    public function createIfNotExists($tagName)
    {
        // Check if a tag exists
        $stmt = $this->db->prepare("SELECT id FROM tags WHERE name = :name LIMIT 1");
        $stmt->execute(['name' => $tagName]);
        $tag = $stmt->fetch(PDO::FETCH_ASSOC);
        
        if ($tag) {
            return $tag['id'];
        }
        
        // If not, then create 
        $stmt = $this->db->prepare("INSERT INTO tags (name) VALUES (:name)");
        $stmt->execute(['name' => $tagName]);
        return $this->db->lastInsertId();
    }

    public function addTagToPost($postId, $tagId)
    {
        $stmt = $this->db->prepare("INSERT IGNORE INTO post_tags (post_id, tag_id) VALUES (:post_id, :tag_id)");
        return $stmt->execute([
            'post_id' => $postId,
            'tag_id'  => $tagId
        ]);
    }

    public function getTagsByPostId($postId)
    {
        $stmt = $this->db->prepare("
            SELECT t.* FROM tags t
            JOIN post_tags pt ON t.id = pt.tag_id
            WHERE pt.post_id = :post_id
        ");
        $stmt->execute(['post_id' => $postId]);
        return $stmt->fetchAll(PDO::FETCH_ASSOC);
    }

    public function getPostsByTagName($tagName)
    {
        $stmt = $this->db->prepare("
            SELECT p.* 
            FROM posts p
            JOIN post_tags pt ON p.id = pt.post_id
            JOIN tags t ON t.id = pt.tag_id
            WHERE t.name = :tagName
            ORDER BY p.created_at DESC
        ");
        $stmt->execute(['tagName' => $tagName]);
        return $stmt->fetchAll(PDO::FETCH_ASSOC);
    }

    public function removeAllTagsFromPost($postId)
    {
        $stmt = $this->db->prepare("DELETE FROM post_tags WHERE post_id = :post_id");
        return $stmt->execute(['post_id' => $postId]);
    }

    public function getAllTagsWithCounts()
    {
        $sql = "
            SELECT 
                t.id,
                t.name,
                COUNT(pt.post_id) AS total
            FROM tags t
            LEFT JOIN post_tags pt ON t.id = pt.tag_id
            GROUP BY t.id, t.name
            HAVING COUNT(pt.post_id) != 0
            ORDER BY total DESC;
        ";
        $stmt = $this->db->query($sql);
        return $stmt->fetchAll(\PDO::FETCH_ASSOC);
    }
}