<?php
/**
 * SavedFiltersModel
 * Handles saving, loading, and managing user's custom search filters
 */
class SavedFiltersModel {
    private $conn;

    public function __construct($conn) {
        $this->conn = $conn;
    }

    /**
     * Get all saved filters for a user
     */
    public function getUserFilters($userId) {
        $sql = "SELECT filter_id, filter_name, filter_criteria, is_default, created_at, updated_at
                FROM saved_filters
                WHERE user_id = ?
                ORDER BY is_default DESC, filter_name ASC";
        $stmt = $this->conn->prepare($sql);
        $stmt->bind_param("i", $userId);
        $stmt->execute();
        $result = $stmt->get_result();

        $filters = [];
        while ($row = $result->fetch_assoc()) {
            $row['filter_criteria'] = json_decode($row['filter_criteria'], true);
            $filters[] = $row;
        }
        return $filters;
    }

    /**
     * Get a specific saved filter
     */
    public function getFilter($filterId, $userId) {
        $sql = "SELECT filter_id, filter_name, filter_criteria, is_default
                FROM saved_filters
                WHERE filter_id = ? AND user_id = ?";
        $stmt = $this->conn->prepare($sql);
        $stmt->bind_param("ii", $filterId, $userId);
        $stmt->execute();
        $result = $stmt->get_result();

        if ($row = $result->fetch_assoc()) {
            $row['filter_criteria'] = json_decode($row['filter_criteria'], true);
            return $row;
        }
        return null;
    }

    /**
     * Save a new filter
     */
    public function saveFilter($userId, $filterName, $filterCriteria, $isDefault = false) {
        // If this is set as default, unset all other defaults for this user
        if ($isDefault) {
            $this->clearDefaultFilters($userId);
        }

        $sql = "INSERT INTO saved_filters (user_id, filter_name, filter_criteria, is_default)
                VALUES (?, ?, ?, ?)
                ON DUPLICATE KEY UPDATE
                    filter_criteria = VALUES(filter_criteria),
                    is_default = VALUES(is_default),
                    updated_at = CURRENT_TIMESTAMP";

        $stmt = $this->conn->prepare($sql);
        $criteriaJson = json_encode($filterCriteria);
        $stmt->bind_param("issi", $userId, $filterName, $criteriaJson, $isDefault);

        if ($stmt->execute()) {
            return [
                'success' => true,
                'filter_id' => $stmt->insert_id ?: $this->getFilterIdByName($userId, $filterName)
            ];
        }
        return ['success' => false, 'error' => $this->conn->error];
    }

    /**
     * Update an existing filter
     */
    public function updateFilter($filterId, $userId, $filterName, $filterCriteria, $isDefault = false) {
        // Verify ownership
        $existing = $this->getFilter($filterId, $userId);
        if (!$existing) {
            return ['success' => false, 'error' => 'Filter not found'];
        }

        // If this is set as default, unset all other defaults for this user
        if ($isDefault) {
            $this->clearDefaultFilters($userId);
        }

        $sql = "UPDATE saved_filters
                SET filter_name = ?, filter_criteria = ?, is_default = ?, updated_at = CURRENT_TIMESTAMP
                WHERE filter_id = ? AND user_id = ?";

        $stmt = $this->conn->prepare($sql);
        $criteriaJson = json_encode($filterCriteria);
        $stmt->bind_param("ssiii", $filterName, $criteriaJson, $isDefault, $filterId, $userId);

        if ($stmt->execute()) {
            return ['success' => true];
        }
        return ['success' => false, 'error' => $this->conn->error];
    }

    /**
     * Delete a saved filter
     */
    public function deleteFilter($filterId, $userId) {
        $sql = "DELETE FROM saved_filters WHERE filter_id = ? AND user_id = ?";
        $stmt = $this->conn->prepare($sql);
        $stmt->bind_param("ii", $filterId, $userId);

        if ($stmt->execute() && $stmt->affected_rows > 0) {
            return ['success' => true];
        }
        return ['success' => false, 'error' => 'Filter not found'];
    }

    /**
     * Set a filter as default
     */
    public function setDefaultFilter($filterId, $userId) {
        // First, clear all defaults
        $this->clearDefaultFilters($userId);

        // Then set this one as default
        $sql = "UPDATE saved_filters SET is_default = 1 WHERE filter_id = ? AND user_id = ?";
        $stmt = $this->conn->prepare($sql);
        $stmt->bind_param("ii", $filterId, $userId);

        if ($stmt->execute()) {
            return ['success' => true];
        }
        return ['success' => false, 'error' => $this->conn->error];
    }

    /**
     * Get the default filter for a user
     */
    public function getDefaultFilter($userId) {
        $sql = "SELECT filter_id, filter_name, filter_criteria
                FROM saved_filters
                WHERE user_id = ? AND is_default = 1
                LIMIT 1";
        $stmt = $this->conn->prepare($sql);
        $stmt->bind_param("i", $userId);
        $stmt->execute();
        $result = $stmt->get_result();

        if ($row = $result->fetch_assoc()) {
            $row['filter_criteria'] = json_decode($row['filter_criteria'], true);
            return $row;
        }
        return null;
    }

    /**
     * Clear all default filters for a user (helper method)
     */
    private function clearDefaultFilters($userId) {
        $sql = "UPDATE saved_filters SET is_default = 0 WHERE user_id = ?";
        $stmt = $this->conn->prepare($sql);
        $stmt->bind_param("i", $userId);
        $stmt->execute();
    }

    /**
     * Get filter ID by name (helper method)
     */
    private function getFilterIdByName($userId, $filterName) {
        $sql = "SELECT filter_id FROM saved_filters WHERE user_id = ? AND filter_name = ?";
        $stmt = $this->conn->prepare($sql);
        $stmt->bind_param("is", $userId, $filterName);
        $stmt->execute();
        $result = $stmt->get_result();

        if ($row = $result->fetch_assoc()) {
            return $row['filter_id'];
        }
        return null;
    }
}
?>