<?php
declare(strict_types=1);

namespace App\Domain\User;

require_once __DIR__ . '/PasswordPolicy.php';
require_once __DIR__ . '/UserRecord.php';

/**
 * PDO-independent validation contracts for user administration actions.
 * Persistence and authorization middleware remain the caller's responsibility.
 */
final class UserAdminService
{
    public function __construct(
        private readonly ?UserRecord $users = null,
        private readonly ?PasswordPolicy $passwordPolicy = null,
    ) {
    }

    /** @return array<string, mixed> */
    public function validate(array $input, array $existingUsers = [], ?int $currentId = null): array
    {
        $result = ($this->users ?? new UserRecord())->validate($input);
        $email = $result['email'] ?? '';
        if ($currentId !== null && is_string($email) && $email !== '' && $this->hasDuplicateEmail($email, $existingUsers, $currentId)) {
            $result['errors']['email'] = 'Email address is already in use.';
        }
        $result['valid'] = $result['errors'] === [];
        return $result;
    }

    /** Controller-friendly user-create DTO. */
    public function validateForCreate(array $input, array $existingUsers = []): array
    {
        $result = ($this->users ?? new UserRecord())->validateForCreate($input);
        $email = $result['email'] ?? '';
        if (is_string($email) && $email !== '' && $this->hasDuplicateEmail($email, $existingUsers, 0)) {
            $result['errors']['email'] = 'Email address is already in use.';
            $result['valid'] = false;
        }
        return $result;
    }

    /** @return array<string, mixed> */
    public function validateForEdit(int $id, array $input, array $existingUsers = []): array
    {
        $errors = [];
        if ($id < 1) {
            $errors['id'] = 'User ID must be a positive integer.';
        }

        $result = ($this->users ?? new UserRecord())->validate($input);
        $existing = $existingUsers[array_search($id, array_map(static fn($row) => is_array($row) ? (int)($row['id'] ?? 0) : 0, $existingUsers), true)] ?? [];
        if ($this->isProtectedAdministrator(['id' => $id, ...$existing]) && array_key_exists('role_id', $input) && (int)$input['role_id'] !== 1) $result['errors']['role_id'] = 'The protected Administrator account cannot be reassigned.';
        $email = $result['email'] ?? '';
        if (is_string($email) && $email !== '' && $this->hasDuplicateEmail($email, $existingUsers, $id)) {
            $result['errors']['email'] = 'Email address is already in use.';
        }

        $result['id'] = $id;
        $result['errors'] = [...$errors, ...$result['errors']];
        $result['valid'] = $result['errors'] === [];
        return $result;
    }

    /** Alias matching controller command terminology. */
    public function validateEdit(int $id, array $input, array $existingUsers = []): array
    {
        return $this->validateForEdit($id, $input, $existingUsers);
    }

    /** @return array{valid: bool, id: int, is_active: bool, errors: array<string, string>} */
    public function validateDeactivate(array $user): array
    {
        return $this->validateTransition($user, true, false, 'deactivated');
    }

    /** @return array{valid: bool, id: int, is_active: bool, errors: array<string, string>} */
    public function validateReactivate(array $user): array
    {
        return $this->validateTransition($user, false, true, 'reactivated');
    }

    /** @return array{valid: bool, id: int, is_active: bool, errors: array<string, string>} */
    public function deactivate(array $user): array
    {
        return $this->validateDeactivate($user);
    }

    /** @return array{valid: bool, id: int, is_active: bool, errors: array<string, string>} */
    public function reactivate(array $user): array
    {
        return $this->validateReactivate($user);
    }

    /** Validate reset input without ever returning the plaintext password. */
    /** @return array{valid: bool, errors: array<string, string>} */
    public function validatePasswordReset(array $user, mixed $password = null): array
    {
        $payload = $password === null && array_key_exists('password', $user);
        if ($payload) $password = $user['password'];

        $errors = [];
        if (!$payload && $this->positiveId($user['id'] ?? null) === null) {
            $errors['id'] = 'User ID must be a positive integer.';
        }
        $check = ($this->passwordPolicy ?? new PasswordPolicy())->validateReset($password);
        if (!$check['valid']) {
            $errors['password'] = 'Password requires: ' . implode(', ', $check['errors']) . '.';
        }
        return ['valid' => $errors === [], 'errors' => $errors];
    }

    /** Aliases useful to controllers accepting a reset command payload. */
    /** @return array{valid: bool, errors: array<string, string>} */
    public function validateReset(array $user, mixed $password = null): array
    {
        return $this->validatePasswordReset($user, $password);
    }

    /** @return array{valid: bool, errors: array<string, string>} */
    public function validateResetPassword(array $user, mixed $password = null): array
    {
        return $this->validatePasswordReset($user, $password);
    }

    /** @return array<string, mixed> */
    public function display(array $user): array
    {
        return ($this->users ?? new UserRecord())->display($user);
    }

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

    public function isProtectedAdministrator(array $user): bool
    {
        if (isset($user['id']) && (int)$user['id'] === 1) return true;
        if (isset($user['role_id']) && (int)$user['role_id'] === 1) return true;
        $role = $user['role_name'] ?? $user['role'] ?? null;
        return is_scalar($role) && strtolower(trim((string) $role)) === 'administrator';
    }

    private function validateTransition(array $user, bool $from, bool $to, string $action): array
    {
        $id = $this->positiveId($user['id'] ?? null);
        $active = $this->asBool($user['is_active'] ?? $user['active'] ?? null);
        $errors = [];
        if ($id === null) {
            $errors['id'] = 'User ID must be a positive integer.';
        }
        if ($this->isProtectedAdministrator($user)) {
            $errors['role'] = 'The protected Administrator account cannot be deactivated.';
        } elseif ($active !== $from) {
            $errors['is_active'] = "Only {$this->stateName($from)} users can be {$action}.";
        }
        return ['valid' => $errors === [], 'id' => $id ?? 0, 'is_active' => $to, 'errors' => $errors];
    }

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

    private function stateName(bool $active): string
    {
        return $active ? 'active' : 'inactive';
    }

    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 $value): ?bool
    {
        if (is_bool($value)) return $value;
        if (is_int($value) && ($value === 0 || $value === 1)) return $value === 1;
        if (is_string($value)) {
            $value = strtolower(trim($value));
            if (in_array($value, ['1', 'true', 'yes', 'on'], true)) return true;
            if (in_array($value, ['0', 'false', 'no', 'off'], true)) return false;
        }
        return null;
    }
}