<?php
declare(strict_types=1);

function normalize_title_key(string $value): string
{
    $value = trim(mb_strtolower($value, 'UTF-8'));
    if ($value === '') {
        return '';
    }

    if (function_exists('iconv')) {
        $transliterated = iconv('UTF-8', 'ASCII//TRANSLIT//IGNORE', $value);
        if ($transliterated !== false) {
            $value = $transliterated;
        }
    }

    $value = preg_replace('/[^a-z0-9]+/', ' ', $value) ?? '';
    return trim($value);
}

function normalize_match_key(string $value): string
{
    return normalize_title_key($value);
}

function detect_product_family_key(string $normalizedName): ?string
{
    if (str_contains($normalizedName, 'lion') && str_contains($normalizedName, 'mane')) {
        return 'lionsmane';
    }
    if (str_contains($normalizedName, 'chaga')) {
        return 'chaga';
    }
    if (str_contains($normalizedName, 'reishi')) {
        return 'reishi';
    }
    if (str_contains($normalizedName, 'shiitake')) {
        return 'shiitake';
    }

    return null;
}

function title_contains_family(string $normalizedTitle, string $familyKey): bool
{
    return $familyKey !== '' && str_contains($normalizedTitle, $familyKey);
}

function resolve_otc_product(PDO $pdo, string $title): array
{
    $normalizedTitle = normalize_match_key($title);
    $familyKey = detect_product_family_key($normalizedTitle);
    if ($familyKey === null) {
        throw new RuntimeException("Kein Produkt-Matching fuer '{$title}' gefunden");
    }

    $stmt = $pdo->query("SELECT id, sku, name FROM product WHERE status = 'active' ORDER BY id");
    foreach ($stmt->fetchAll() as $product) {
        $productName = (string) ($product['name'] ?? '');
        $productKey = detect_product_family_key(normalize_match_key($productName));
        if ($productKey === $familyKey) {
            return [
                'id' => (int) $product['id'],
                'sku' => (string) $product['sku'],
                'name' => $productName,
            ];
        }
    }

    throw new RuntimeException("Kein aktives ERP-Produkt fuer '{$title}' gefunden");
}

function find_alias_sellable_item_id(PDO $pdo, string $articleNumber, string $title): ?int
{
    $stmt = $pdo->prepare(
        "SELECT si.id
         FROM external_item_alias eia
         JOIN sellable_item si ON si.id = eia.sellable_item_id
         WHERE eia.source_system = 'wix'
           AND eia.is_active = TRUE
           AND (
             eia.external_article_number = :article_number
             OR eia.external_title = :title
             OR eia.title_normalized = :normalized_title
           )
         ORDER BY eia.id
         LIMIT 1"
    );
    $stmt->execute([
        ':article_number' => trim($articleNumber),
        ':title' => trim($title),
        ':normalized_title' => normalize_match_key($title),
    ]);

    $id = $stmt->fetchColumn();
    return $id === false ? null : (int) $id;
}

function sellable_item_exists(PDO $pdo, int $sellableItemId): bool
{
    $stmt = $pdo->prepare('SELECT 1 FROM sellable_item WHERE id = :id LIMIT 1');
    $stmt->execute([':id' => $sellableItemId]);
    return $stmt->fetchColumn() !== false;
}

function find_sellable_item_for_product(PDO $pdo, int $productId): ?int
{
    $stmt = $pdo->prepare(
        'SELECT sellable_item_id
         FROM sellable_item_component
         WHERE product_id = :product_id
         ORDER BY id
         LIMIT 1'
    );
    $stmt->execute([':product_id' => $productId]);
    $id = $stmt->fetchColumn();
    return $id === false ? null : (int) $id;
}

function find_product_name(PDO $pdo, int $productId): ?string
{
    $stmt = $pdo->prepare('SELECT name FROM product WHERE id = :id LIMIT 1');
    $stmt->execute([':id' => $productId]);
    $name = $stmt->fetchColumn();
    return $name === false ? null : (string) $name;
}

function ensure_unique_sellable_item_code(PDO $pdo, string $preferred): string
{
    $candidate = trim($preferred);
    if ($candidate === '') {
        $candidate = 'si';
    }

    $base = $candidate;
    $counter = 1;
    while (true) {
        $stmt = $pdo->prepare('SELECT 1 FROM sellable_item WHERE item_code = :item_code LIMIT 1');
        $stmt->execute([':item_code' => $candidate]);
        if ($stmt->fetchColumn() === false) {
            return $candidate;
        }

        $candidate = $base . '-' . $counter;
        $counter++;
    }
}

function resolve_product_id_fallback(PDO $pdo, string $articleNumber, string $title): ?int
{
    $normalizedTitle = normalize_match_key($title);
    $familyKey = detect_product_family_key($normalizedTitle);
    if ($familyKey === null) {
        return null;
    }

    $stmt = $pdo->query("SELECT id, name FROM product WHERE status = 'active' ORDER BY id");
    foreach ($stmt->fetchAll() as $product) {
        $productName = (string) ($product['name'] ?? '');
        $productKey = detect_product_family_key(normalize_match_key($productName));
        if ($productKey === $familyKey) {
            return (int) $product['id'];
        }
    }

    return null;
}

function infer_components_from_title(PDO $pdo, string $title): array
{
    $productId = resolve_product_id_fallback($pdo, '', $title);
    if ($productId === null) {
        return [];
    }

    return [['product_id' => $productId, 'qty_per_item' => 1.0]];
}

function ensure_alias_points_to_sellable_item(
    PDO $pdo,
    string $articleNumber,
    string $title,
    int $sellableItemId
): void {
    $stmt = $pdo->prepare(
        "INSERT INTO external_item_alias (
            source_system, external_article_number, external_title, title_normalized, sellable_item_id, is_active, created_at, updated_at
         ) VALUES (
            'wix', :article_number, :title, :normalized_title, :sellable_item_id, TRUE, NOW(), NOW()
         )
         ON CONFLICT DO NOTHING"
    );
    $stmt->execute([
        ':article_number' => trim($articleNumber),
        ':title' => trim($title),
        ':normalized_title' => normalize_match_key($title),
        ':sellable_item_id' => $sellableItemId,
    ]);
}

function ensure_sellable_mapping_from_title_components(PDO $pdo, string $articleNumber, string $title): ?int
{
    $sellableItemId = find_alias_sellable_item_id($pdo, $articleNumber, $title);
    if ($sellableItemId !== null) {
        return $sellableItemId;
    }

    $components = infer_components_from_title($pdo, $title);
    if ($components === []) {
        return null;
    }

    $productId = (int) $components[0]['product_id'];
    $sellableItemId = find_sellable_item_for_product($pdo, $productId);
    if ($sellableItemId === null) {
        $productName = find_product_name($pdo, $productId) ?? 'Mapped item';
        $code = ensure_unique_sellable_item_code($pdo, normalize_match_key($productName));
        $stmt = $pdo->prepare(
            "INSERT INTO sellable_item (item_code, display_name, status, created_at, updated_at)
             VALUES (:item_code, :display_name, 'active', NOW(), NOW())
             RETURNING id"
        );
        $stmt->execute([
            ':item_code' => $code,
            ':display_name' => $productName,
        ]);
        $sellableItemId = (int) $stmt->fetchColumn();

        $componentStmt = $pdo->prepare(
            "INSERT INTO sellable_item_component (sellable_item_id, product_id, qty_per_item, created_at, updated_at)
             VALUES (:sellable_item_id, :product_id, 1, NOW(), NOW())"
        );
        $componentStmt->execute([
            ':sellable_item_id' => $sellableItemId,
            ':product_id' => $productId,
        ]);
    }

    ensure_alias_points_to_sellable_item($pdo, $articleNumber, $title, $sellableItemId);

    return $sellableItemId;
}

function ensure_sellable_mapping_from_product_fallback(PDO $pdo, string $articleNumber, string $title): ?int
{
    return ensure_sellable_mapping_from_title_components($pdo, $articleNumber, $title);
}

function resolve_sellable_item_id(PDO $pdo, string $articleNumber, string $title): ?int
{
    $id = find_alias_sellable_item_id($pdo, $articleNumber, $title);
    if ($id !== null) {
        return $id;
    }

    return ensure_sellable_mapping_from_product_fallback($pdo, $articleNumber, $title);
}

function get_item_components(PDO $pdo, int $sellableItemId): array
{
    $stmt = $pdo->prepare(
        'SELECT product_id, qty_per_item
         FROM sellable_item_component
         WHERE sellable_item_id = :sellable_item_id
         ORDER BY id'
    );
    $stmt->execute([':sellable_item_id' => $sellableItemId]);

    return $stmt->fetchAll();
}