<?php
declare(strict_types=1);

namespace App\Domain\SLA;

final class SlaAgreement
{
    /** @var list<string> */
    private const DISPLAY_FIELDS = [
        'id',
        'client_id',
        'enabled',
        'agreement_type',
        'allocated_hours',
        'period_type',
        'start_date',
        'end_date',
        'rollover_enabled',
        'notes',
    ];

    /** @return array{client_id: int, enabled: bool, agreement_type: string|null, allocated_hours: float, period_type: string, start_date: string|null, end_date: string|null, rollover_enabled: bool, notes: string|null} */
    public function normalize(array $record): array
    {
        return [
            'client_id' => $this->integer($record['client_id'] ?? null),
            'enabled' => $this->boolean($record['enabled'] ?? true, true),
            'agreement_type' => $this->text($record['agreement_type'] ?? null),
            'allocated_hours' => $this->number($record['allocated_hours'] ?? 0),
            'period_type' => strtolower($this->text($record['period_type'] ?? null) ?? 'monthly'),
            'start_date' => $this->text($record['start_date'] ?? null),
            'end_date' => $this->text($record['end_date'] ?? null),
            'rollover_enabled' => $this->boolean($record['rollover_enabled'] ?? false, false),
            'notes' => $this->text($record['notes'] ?? null),
        ];
    }

    /** @return array{valid: bool, errors: array<string, string>, client_id: int, enabled: bool, agreement_type: string|null, allocated_hours: float, period_type: string, start_date: string|null, end_date: string|null, rollover_enabled: bool, notes: string|null} */
    public function validate(array $record): array
    {
        $normalized = $this->normalize($record);
        $errors = [];

        if (!$this->positiveInteger($record['client_id'] ?? null)) {
            $errors['client_id'] = 'Client ID must be a positive integer.';
        }
        if (!$this->validBoolean($record['enabled'] ?? true)) {
            $errors['enabled'] = 'Enabled must be a boolean value.';
        }
        if (!$this->nullableScalar($record['agreement_type'] ?? null)) {
            $errors['agreement_type'] = 'Agreement type must be text.';
        } elseif ($normalized['agreement_type'] !== null && $this->length($normalized['agreement_type']) > 120) {
            $errors['agreement_type'] = 'Agreement type must be 120 characters or fewer.';
        }
        if (!is_numeric($record['allocated_hours'] ?? 0) || !is_finite((float) ($record['allocated_hours'] ?? 0))) {
            $errors['allocated_hours'] = 'Allocated hours must be a finite number.';
        } elseif ($normalized['allocated_hours'] < 0) {
            $errors['allocated_hours'] = 'Allocated hours must not be negative.';
        }
        if (!$this->nullableScalar($record['period_type'] ?? null)
            || !in_array($normalized['period_type'], ['monthly', 'annual', 'custom'], true)) {
            $errors['period_type'] = 'Period type must be monthly, annual, or custom.';
        }
        if (!$this->nullableScalar($record['start_date'] ?? null)) {
            $errors['start_date'] = 'Start date must be a valid date in YYYY-MM-DD format.';
        } elseif ($normalized['start_date'] !== null && !$this->validDate($normalized['start_date'])) {
            $errors['start_date'] = 'Start date must be a valid date in YYYY-MM-DD format.';
        }
        if (!$this->nullableScalar($record['end_date'] ?? null)) {
            $errors['end_date'] = 'End date must be a valid date in YYYY-MM-DD format.';
        } elseif ($normalized['end_date'] !== null && !$this->validDate($normalized['end_date'])) {
            $errors['end_date'] = 'End date must be a valid date in YYYY-MM-DD format.';
        }
        if (!isset($errors['start_date'])
            && !isset($errors['end_date'])
            && $normalized['start_date'] !== null
            && $normalized['end_date'] !== null
            && $normalized['start_date'] > $normalized['end_date']) {
            $errors['end_date'] = 'End date must not be before start date.';
        }
        if (!$this->validBoolean($record['rollover_enabled'] ?? false)) {
            $errors['rollover_enabled'] = 'Rollover enabled must be a boolean value.';
        } elseif ($normalized['rollover_enabled']) {
            $errors['rollover_enabled'] = 'Rollover cannot be enabled until rollover rules are configured.';
        }
        if (!$this->nullableScalar($record['notes'] ?? null)) {
            $errors['notes'] = 'Notes must be text.';
        }

        return [...$normalized, 'valid' => $errors === [], 'errors' => $errors];
    }

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

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

    private function integer(mixed $value): int
    {
        $text = is_int($value) || is_string($value) ? trim((string) $value) : '';
        return preg_match('/^\d+$/', $text) === 1 ? (int) $text : 0;
    }

    private function positiveInteger(mixed $value): bool
    {
        if (is_int($value)) return $value > 0;
        if (!is_string($value)) return false;
        $value = trim($value);
        return preg_match('/^\d+$/', $value) === 1 && (int) $value > 0;
    }

    private function number(mixed $value): float
    {
        return is_numeric($value) && is_finite((float) $value) ? (float) $value : 0.0;
    }

    private function boolean(mixed $value, bool $default): bool
    {
        if (is_bool($value)) return $value;
        if ($value === 1 || $value === 0) 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 $default;
    }

    private function validBoolean(mixed $value): bool
    {
        if (is_bool($value) || $value === 0 || $value === 1) return true;
        if (!is_string($value)) return false;
        return in_array(strtolower(trim($value)), ['1', '0', 'true', 'false', 'yes', 'no', 'on', 'off', ''], true);
    }

    private function nullableScalar(mixed $value): bool
    {
        return $value === null || is_scalar($value);
    }

    private function validDate(string $value): bool
    {
        $date = \DateTimeImmutable::createFromFormat('!Y-m-d', $value);
        $errors = \DateTimeImmutable::getLastErrors();
        return $date !== false
            && ($errors === false || ($errors['warning_count'] === 0 && $errors['error_count'] === 0))
            && $date->format('Y-m-d') === $value;
    }

    private function length(string $value): int
    {
        return function_exists('mb_strlen') ? mb_strlen($value) : strlen($value);
    }

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