<?php
class Invitation {
    private $db;

    public function __construct() {
        $this->db = new Database();
    }

    public function create(array $assignedProjects = [], ?string $note = null, int $maxUses = 1, ?string $expiresAt = null): string {
        $token = bin2hex(random_bytes(24)); // 48-char secure hex token
        $projectsJson = json_encode(array_values(array_filter($assignedProjects)));

        $sql = "INSERT INTO home_invitations (token, assigned_projects, max_uses, uses_count, expires_at, note) 
                VALUES (:token, :assigned_projects, :max_uses, 0, :expires_at, :note)";
        $this->db->query($sql);
        $this->db->bind(':token', $token);
        $this->db->bind(':assigned_projects', $projectsJson);
        $this->db->bind(':max_uses', $maxUses);
        $this->db->bind(':expires_at', $expiresAt);
        $this->db->bind(':note', $note);
        $this->db->execute();

        return $token;
    }

    public function getByToken(string $token): ?array {
        $sql = "SELECT * FROM home_invitations WHERE LOWER(token) = LOWER(:token)";
        $this->db->query($sql);
        $this->db->bind(':token', $token);
        $invitation = $this->db->single();

        if (!$invitation) {
            return null;
        }

        // Check uses count
        if ($invitation['max_uses'] > 0 && $invitation['uses_count'] >= $invitation['max_uses']) {
            return null;
        }

        // Check expiration
        if (!empty($invitation['expires_at'])) {
            $now = new DateTime();
            $expires = new DateTime($invitation['expires_at']);
            if ($now > $expires) {
                return null;
            }
        }

        $invitation['assigned_projects'] = json_decode($invitation['assigned_projects'] ?? '[]', true) ?? [];
        return $invitation;
    }

    public function recordUse(string $token): bool {
        $sql = "UPDATE home_invitations SET uses_count = uses_count + 1 WHERE LOWER(token) = LOWER(:token)";
        $this->db->query($sql);
        $this->db->bind(':token', $token);
        return $this->db->execute();
    }

    public function getAll(): array {
        $sql = "SELECT * FROM home_invitations ORDER BY id DESC";
        $this->db->query($sql);
        $invitations = $this->db->resultSet();

        foreach ($invitations as &$inv) {
            $inv['assigned_projects'] = json_decode($inv['assigned_projects'] ?? '[]', true) ?? [];
            $isExpired = false;
            if (!empty($inv['expires_at'])) {
                $isExpired = (new DateTime()) > (new DateTime($inv['expires_at']));
            }
            $isDepleted = ($inv['max_uses'] > 0 && $inv['uses_count'] >= $inv['max_uses']);
            $inv['is_valid'] = (!$isExpired && !$isDepleted);
        }

        return $invitations;
    }

    public function delete(int $id): bool {
        $sql = "DELETE FROM home_invitations WHERE id = :id";
        $this->db->query($sql);
        $this->db->bind(':id', $id);
        return $this->db->execute();
    }
}