<?php
register_activation_hook( __FILE__, 'caz_create_flash_sale_table' );

function caz_create_flash_sale_table(): void {
    global $wpdb;
    $table   = $wpdb->prefix . 'caz_flash_sales';
    $charset = $wpdb->get_charset_collate();

    $sql = "CREATE TABLE IF NOT EXISTS {$table} (
        id           BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
        name         VARCHAR(200)    NOT NULL,
        product_ids  LONGTEXT        NOT NULL,
        sale_percent DECIMAL(5,2)    NOT NULL DEFAULT 0,
        sale_amount  DECIMAL(10,2)   NOT NULL DEFAULT 0,
        start_time   DATETIME        NOT NULL,
        end_time     DATETIME        NOT NULL,
        status       VARCHAR(20)     NOT NULL DEFAULT 'scheduled',
        created_at   DATETIME        NOT NULL DEFAULT CURRENT_TIMESTAMP,
        PRIMARY KEY  (id),
        KEY          (status),
        KEY          (start_time),
        KEY          (end_time)
    ) {$charset};";

    require_once ABSPATH . 'wp-admin/includes/upgrade.php';
    dbDelta( $sql );
}

// Schedule WooCommerce flash sale automation when a sale is saved
function caz_schedule_flash_sale( array $sale_data ): int {
    global $wpdb;
    $table = $wpdb->prefix . 'caz_flash_sales';

    $id = $wpdb->insert( $table, [
        'name'         => sanitize_text_field( $sale_data['name'] ),
        'product_ids'  => wp_json_encode( array_map( 'absint', $sale_data['product_ids'] ) ),
        'sale_percent' => (float) $sale_data['percent'],
        'sale_amount'  => (float) $sale_data['amount'],
        'start_time'   => $sale_data['start'],
        'end_time'     => $sale_data['end'],
        'status'       => 'scheduled',
    ]);

    // Schedule activation using Action Scheduler for reliable WooCommerce flash sale automation
    as_schedule_single_action(
        strtotime( $sale_data['start'] ),
        'caz_activate_flash_sale',
        [ 'sale_id' => $wpdb->insert_id ],
        'caz-flash-sales'
    );

    return (int) $wpdb->insert_id;
}

<?php
add_action( 'caz_activate_flash_sale', 'caz_run_flash_sale_activation' );

function caz_run_flash_sale_activation( int $sale_id ): void {
    global $wpdb;
    $sale = $wpdb->get_row(
        $wpdb->prepare( "SELECT * FROM {$wpdb->prefix}caz_flash_sales WHERE id=%d", $sale_id )
    );
    if ( ! $sale || $sale->status !== 'scheduled' ) return;

    $product_ids = json_decode( $sale->product_ids, true );

    foreach ( $product_ids as $id ) {
        $product = wc_get_product( $id );
        if ( ! $product ) continue;

        $regular = (float) $product->get_regular_price();
        // Calculate flash sale price
        $flash_price = $sale->sale_percent > 0
            ? round( $regular * ( 1 - $sale->sale_percent / 100 ), 2 )
            : max( 0, $regular - $sale->sale_amount );

        // Store original price so WooCommerce flash sale automation can restore it
        $product->update_meta_data( '_caz_pre_flash_price', $product->get_sale_price() );
        $product->update_meta_data( '_caz_flash_sale_id',   $sale_id );
        $product->set_sale_price( (string) $flash_price );
        $product->set_date_on_sale_from( null );
        $product->set_date_on_sale_to( null );
        $product->save();
    }

    // Mark active in DB
    $wpdb->update(
        $wpdb->prefix . 'caz_flash_sales',
        [ 'status' => 'active' ],
        [ 'id' => $sale_id ]
    );

    // Schedule expiry for WooCommerce flash sale automation
    as_schedule_single_action(
        strtotime( $sale->end_time ),
        'caz_expire_flash_sale',
        [ 'sale_id' => $sale_id ],
        'caz-flash-sales'
    );

    do_action( 'caz_flash_sale_activated', $sale_id, $product_ids );
}

add_action( 'caz_expire_flash_sale', 'caz_run_flash_sale_expiry' );

function caz_run_flash_sale_expiry( int $sale_id ): void {
    global $wpdb;
    $sale = $wpdb->get_row(
        $wpdb->prepare( "SELECT * FROM {$wpdb->prefix}caz_flash_sales WHERE id=%d", $sale_id )
    );
    if ( ! $sale ) return;

    $product_ids = json_decode( $sale->product_ids, true );
    foreach ( $product_ids as $id ) {
        $product = wc_get_product( $id );
        if ( ! $product ) continue;
        // Restore pre-flash sale price — WooCommerce flash sale automation cleanup
        $orig = $product->get_meta( '_caz_pre_flash_price' );
        $product->set_sale_price( $orig ?: '' );
        $product->delete_meta_data( '_caz_flash_sale_id' );
        $product->delete_meta_data( '_caz_pre_flash_price' );
        $product->save();
    }

    $wpdb->update(
        $wpdb->prefix . 'caz_flash_sales',
        [ 'status' => 'expired' ],
        [ 'id' => $sale_id ]
    );

    do_action( 'caz_flash_sale_expired', $sale_id, $product_ids );
}

add_action( 'caz_flash_sale_activated', 'caz_send_flash_sale_email', 10, 2 );

function caz_send_flash_sale_email( int $sale_id, array $product_ids ): void {
    global $wpdb;
    $sale = $wpdb->get_row( $wpdb->prepare(
        "SELECT * FROM {$wpdb->prefix}caz_flash_sales WHERE id=%d", $sale_id
    ));
    if ( ! $sale ) return;

    // Get all opted-in customer emails for WooCommerce flash sale automation
    $emails = get_option( 'caz_flash_sale_subscribers', [] );
    if ( empty( $emails ) ) return;

    $end_human = date_i18n( get_option('date_format') . ' ' . get_option('time_format'),
                            strtotime( $sale->end_time ) );
    $subject   = sprintf( __( 'Flash Sale LIVE: %s — ends %s', 'caz-scm' ), $sale->name, $end_human );

    // Build product list for the email
    $product_lines = '';
    foreach ( array_slice( $product_ids, 0, 5 ) as $id ) {
        $p = wc_get_product( $id );
        if ( $p ) $product_lines .= '• ' . $p->get_name() . ' — now ' . wc_price( $p->get_sale_price() ) . "n";
    }

    $message = sprintf(
        __( "Your WooCommerce flash sale automation just triggered!nn%s is now live:nn%snShop now: %snnSale ends: %s", 'caz-scm' ),
        $sale->name, $product_lines, get_home_url(), $end_human
    );

    foreach ( $emails as $email ) {
        wp_mail( $email, $subject, $message );
    }
}