<?php
/**
 * DeclarationTVA_Period Class
 * Period management for DeclarationTVA module
 * MVP Version - Phase 1
 */

class DeclarationTVA_Period
{
    /**
     * @var DoliDB Database handler
     */
    public $db;

    /**
     * @var int Entity ID
     */
    public $entity;

    /**
     * @var string Error message
     */
    public $error;

    /**
     * Constructor
     *
     * @param DoliDB $db Database handler
     * @param int $entity Entity ID
     */
    public function __construct($db, $entity = 1)
    {
        $this->db = $db;
        $this->entity = $entity;
    }

    /**
     * Create a new period
     *
     * @param string $period_name Period name (e.g., Q1-2024)
     * @param string $start_date Start date (YYYY-MM-DD)
     * @param string $end_date End date (YYYY-MM-DD)
     * @return int Period ID or -1 if error
     */
    public function createPeriod($period_name, $start_date, $end_date)
    {
        $this->db->begin();

        // Check if period already exists
        if ($this->periodExists($period_name)) {
            $this->error = "Period already exists";
            $this->db->rollback();
            return -1;
        }

        // Create period
        $sql = "INSERT INTO " . MAIN_DB_PREFIX . "declarationtva_periods 
                (entity, period_name, start_date, end_date, status, created_date) 
                VALUES (" . $this->entity . ", '" . $this->db->escape($period_name) . "', 
                '" . $this->db->escape($start_date) . "', '" . $this->db->escape($end_date) . "', 
                'draft', NOW())";

        $result = $this->db->query($sql);
        if (!$result) {
            $this->error = "Error creating period: " . $this->db->lasterror();
            $this->db->rollback();
            return -1;
        }

        $period_id = $this->db->last_insert_id(MAIN_DB_PREFIX . "declarationtva_periods");

        $this->db->commit();
        return $period_id;
    }

    /**
     * Check if period exists
     *
     * @param string $period_name Period name
     * @return bool Exists
     */
    public function periodExists($period_name)
    {
        $sql = "SELECT COUNT(*) as count FROM " . MAIN_DB_PREFIX . "declarationtva_periods 
                WHERE entity = " . $this->entity . " AND period_name = '" . $this->db->escape($period_name) . "'";

        $result = $this->db->query($sql);
        if ($result && $this->db->num_rows($result) > 0) {
            $obj = $this->db->fetch_object($result);
            return $obj->count > 0;
        }

        return false;
    }

    /**
     * Get period information
     *
     * @param int $period_id Period ID
     * @return array|false Period information or false if not found
     */
    public function getPeriod($period_id)
    {
        $sql = "SELECT * FROM " . MAIN_DB_PREFIX . "declarationtva_periods 
                WHERE rowid = " . $period_id . " AND entity = " . $this->entity;

        $result = $this->db->query($sql);
        if ($result && $this->db->num_rows($result) > 0) {
            return $this->db->fetch_array($result);
        }

        return false;
    }

    /**
     * Get all periods
     *
     * @return array Periods
     */
    public function getAllPeriods()
    {
        $sql = "SELECT * FROM " . MAIN_DB_PREFIX . "declarationtva_periods 
                WHERE entity = " . $this->entity . " 
                ORDER BY start_date DESC";

        $result = $this->db->query($sql);
        $periods = array();

        if ($result) {
            while ($obj = $this->db->fetch_object($result)) {
                $periods[] = array(
                    'rowid' => $obj->rowid,
                    'period_name' => $obj->period_name,
                    'start_date' => $obj->start_date,
                    'end_date' => $obj->end_date,
                    'status' => $obj->status,
                    'created_date' => $obj->created_date
                );
            }
        }

        return $periods;
    }

    /**
     * Update period status
     *
     * @param int $period_id Period ID
     * @param string $status New status
     * @return bool Success
     */
    public function updatePeriodStatus($period_id, $status)
    {
        $sql = "UPDATE " . MAIN_DB_PREFIX . "declarationtva_periods 
                SET status = '" . $this->db->escape($status) . "' 
                WHERE rowid = " . $period_id . " AND entity = " . $this->entity;

        $result = $this->db->query($sql);
        return $result !== false;
    }

    /**
     * Generate quarterly periods for a year
     *
     * @param int $year Year
     * @return array Period IDs
     */
    public function generateYearlyPeriods($year)
    {
        $periods = array();
        $quarters = array(
            'Q1' => array('start' => $year . '-01-01', 'end' => $year . '-03-31'),
            'Q2' => array('start' => $year . '-04-01', 'end' => $year . '-06-30'),
            'Q3' => array('start' => $year . '-07-01', 'end' => $year . '-09-30'),
            'Q4' => array('start' => $year . '-10-01', 'end' => $year . '-12-31')
        );

        foreach ($quarters as $quarter => $dates) {
            $period_name = $quarter . '-' . $year;
            
            if (!$this->periodExists($period_name)) {
                $period_id = $this->createPeriod($period_name, $dates['start'], $dates['end']);
                if ($period_id > 0) {
                    $periods[] = $period_id;
                }
            }
        }

        return $periods;
    }

    /**
     * Get current period (based on today's date)
     *
     * @return array|false Current period or false if not found
     */
    public function getCurrentPeriod()
    {
        $today = date('Y-m-d');
        
        $sql = "SELECT * FROM " . MAIN_DB_PREFIX . "declarationtva_periods 
                WHERE entity = " . $this->entity . " 
                AND start_date <= '" . $today . "' 
                AND end_date >= '" . $today . "' 
                ORDER BY start_date DESC 
                LIMIT 1";

        $result = $this->db->query($sql);
        if ($result && $this->db->num_rows($result) > 0) {
            return $this->db->fetch_array($result);
        }

        return false;
    }

    /**
     * Get period by name
     *
     * @param string $period_name Period name
     * @return array|false Period information or false if not found
     */
    public function getPeriodByName($period_name)
    {
        $sql = "SELECT * FROM " . MAIN_DB_PREFIX . "declarationtva_periods 
                WHERE entity = " . $this->entity . " AND period_name = '" . $this->db->escape($period_name) . "'";

        $result = $this->db->query($sql);
        if ($result && $this->db->num_rows($result) > 0) {
            return $this->db->fetch_array($result);
        }

        return false;
    }

    /**
     * Delete period (only if no declarations exist)
     *
     * @param int $period_id Period ID
     * @return bool Success
     */
    public function deletePeriod($period_id)
    {
        // Check if declarations exist for this period
        $sql = "SELECT COUNT(*) as count FROM " . MAIN_DB_PREFIX . "declarationtva_declarations 
                WHERE period_id = " . $period_id . " AND entity = " . $this->entity;

        $result = $this->db->query($sql);
        if ($result && $this->db->num_rows($result) > 0) {
            $obj = $this->db->fetch_object($result);
            if ($obj->count > 0) {
                $this->error = "Cannot delete period with existing declarations";
                return false;
            }
        }

        $sql = "DELETE FROM " . MAIN_DB_PREFIX . "declarationtva_periods 
                WHERE rowid = " . $period_id . " AND entity = " . $this->entity;

        $result = $this->db->query($sql);
        return $result !== false;
    }

    /**
     * Get period statistics
     *
     * @param int $period_id Period ID
     * @return array Statistics
     */
    public function getPeriodStatistics($period_id)
    {
        $sql = "SELECT COUNT(*) as declaration_count, 
                SUM(total_vat_collected) as total_vat_collected,
                SUM(total_vat_deductible) as total_vat_deductible,
                SUM(net_vat_due) as net_vat_due,
                SUM(vat_credit) as vat_credit
                FROM " . MAIN_DB_PREFIX . "declarationtva_declarations 
                WHERE period_id = " . $period_id . " AND entity = " . $this->entity;

        $result = $this->db->query($sql);
        if ($result && $this->db->num_rows($result) > 0) {
            return $this->db->fetch_array($result);
        }

        return array(
            'declaration_count' => 0,
            'total_vat_collected' => 0,
            'total_vat_deductible' => 0,
            'net_vat_due' => 0,
            'vat_credit' => 0
        );
    }
}