<?php
declare(strict_types=1);

namespace App\Domain\Client;

require_once __DIR__ . '/ClientContactValidator.php';

/** Validates client-contact create/edit payloads, including primary promotion. */
final class ContactUpdateCommand
{
    /** @var list<string> */
    private const DISPLAY_FIELDS = ['id', 'client_id', 'name', 'email', 'phone', 'is_primary', 'notes'];

    /** @return array<string, mixed> */
    public function validate(array $input, array $existingContacts = [], ?int $currentId = null): array
    {
        $contact = validate_client_contact($input);
        $contact['name'] = $this->name($contact['name']);
        $clientId = $this->positiveId($input['client_id'] ?? null);
        $notes = $this->text($input['notes'] ?? null);
        $errors = $contact['errors'];
        if ($clientId === null) $errors['client_id'] = 'Client ID must be a positive integer.';
        if ($notes !== null && mb_strlen($notes) > 10000) $errors['notes'] = 'Contact notes must be 10000 characters or fewer.';

        if ($clientId !== null) {
            foreach (['name' => $contact['name'], 'email' => $contact['email']] as $field => $value) {
                if ($value === null || $value === '') continue;
                if ($this->hasDuplicate($field, (string) $value, $clientId, $existingContacts, $currentId)) {
                    $errors[$field] = "Contact {$field} is already in use for this client.";
                }
            }
        }

        $replace = [];
        if ($clientId !== null && $contact['is_primary'] === true) {
            foreach ($existingContacts as $row) {
                if (!is_array($row) || $this->positiveId($row['client_id'] ?? null) !== $clientId) continue;
                if (!$this->asBool($row['is_primary'] ?? false)) continue;
                $id = $this->positiveId($row['id'] ?? null);
                if ($id !== null && $id !== $currentId) $replace[] = $id;
            }
        }

        return [
            'client_id' => $clientId,
            'name' => $contact['name'],
            'email' => $contact['email'],
            'phone' => $contact['phone'],
            'is_primary' => $contact['is_primary'],
            'notes' => $notes,
            'replace_primary_contact_ids' => $replace,
            'valid' => $errors === [],
            'errors' => $errors,
        ];
    }

    /** @return array<string, mixed> */
    public function validateForCreate(array $input, array $existingContacts = []): array
    {
        return $this->validate($input, $existingContacts);
    }

    /** @return array<string, mixed> */
    public function validateForEdit(mixed $id, array $input, array $existingContacts = []): array
    {
        $normalizedId = $this->positiveId($id);
        $result = $this->validate($input, $existingContacts, $normalizedId);
        $result['id'] = $normalizedId;
        if ($normalizedId === null) $result['errors']['id'] = 'Contact ID must be a positive integer.';
        $result['valid'] = $result['errors'] === [];
        return $result;
    }

    /** @return array<string, mixed> */
    public function display(array $contact): array
    {
        $safe = [];
        foreach (self::DISPLAY_FIELDS as $field) {
            if (array_key_exists($field, $contact)) $safe[$field] = $contact[$field];
        }
        return $safe;
    }

    /** @return array<string, mixed> */
    public function toDisplay(array $contact): array
    {
        return $this->display($contact);
    }

    private function hasDuplicate(string $field, string $value, int $clientId, array $rows, ?int $currentId): bool
    {
        $candidate = $field === 'email' ? strtolower(trim($value)) : $this->duplicateKey($value);
        foreach ($rows as $row) {
            if (!is_array($row) || $this->positiveId($row['client_id'] ?? null) !== $clientId) continue;
            $rowId = $this->positiveId($row['id'] ?? null);
            if ($currentId !== null && $rowId === $currentId) continue;
            $other = $row[$field] ?? null;
            if ($other !== null && ($field === 'email' ? strtolower(trim((string) $other)) === $candidate : $this->duplicateKey((string) $other) === $candidate)) return true;
        }
        return false;
    }

    private function duplicateKey(string $value): string
    {
        $collapsed = preg_replace('/\s+/u', ' ', trim($value));
        return strtolower($collapsed === false ? trim($value) : $collapsed);
    }

    private function name(string $value): string
    {
        $collapsed = preg_replace('/\s+/u', ' ', trim($value));
        return $collapsed === false ? trim($value) : $collapsed;
    }

    private function text(mixed $value): ?string
    {
        if (!is_scalar($value)) return null;
        $value = trim((string) $value);
        return $value === '' ? null : $value;
    }

    private function positiveId(mixed $value): ?int
    {
        if (is_int($value) && $value > 0) return $value;
        if (is_string($value) && preg_match('/^[1-9]\d*$/', trim($value)) === 1) {
            $id = filter_var(trim($value), FILTER_VALIDATE_INT);
            return $id === false ? null : $id;
        }
        return null;
    }

    private function asBool(mixed $value): bool
    {
        return $value === true || $value === 1 || (is_string($value) && in_array(strtolower(trim($value)), ['1', 'true', 'yes', 'on'], true));
    }
}