<?php

declare(strict_types=1);

namespace App\Support\Resources;

use Illuminate\Contracts\Support\Arrayable;
use InvalidArgumentException;
use JsonSerializable;

/**
 * @implements Arrayable<string, mixed>
 */
final readonly class ResourceIdentity implements Arrayable, JsonSerializable
{
    public const string ProviderResource = 'provider_resource';

    public const string CanonicalBuiltin = 'canonical_builtin';

    public const string CanonicalDefault = 'canonical_default';

    public const string CanonicalVirtualTarget = 'canonical_virtual_target';

    public const string Unsupported = 'unsupported';

    public const string Unknown = 'unknown';

    public function __construct(
        public string $providerKey,
        public string $identityKind,
        public ?string $providerResourceType = null,
        public ?string $providerResourceId = null,
        public ?string $canonicalDiscriminator = null,
    ) {
        $this->assertValid();
    }

    public static function providerResource(string $providerKey, string $resourceType, string $resourceId): self
    {
        return new self(
            providerKey: $providerKey,
            identityKind: self::ProviderResource,
            providerResourceType: $resourceType,
            providerResourceId: $resourceId,
        );
    }

    public static function canonicalBuiltin(string $providerKey, string $resourceType, string $discriminator): self
    {
        return new self(
            providerKey: $providerKey,
            identityKind: self::CanonicalBuiltin,
            providerResourceType: $resourceType,
            canonicalDiscriminator: $discriminator,
        );
    }

    public static function canonicalDefault(string $providerKey, string $resourceType, string $discriminator): self
    {
        return new self(
            providerKey: $providerKey,
            identityKind: self::CanonicalDefault,
            providerResourceType: $resourceType,
            canonicalDiscriminator: $discriminator,
        );
    }

    public static function virtualTarget(string $providerKey, string $resourceType, string $discriminator): self
    {
        return new self(
            providerKey: $providerKey,
            identityKind: self::CanonicalVirtualTarget,
            providerResourceType: $resourceType,
            canonicalDiscriminator: $discriminator,
        );
    }

    public static function unsupported(string $providerKey, string $resourceType, string $discriminator): self
    {
        return new self(
            providerKey: $providerKey,
            identityKind: self::Unsupported,
            providerResourceType: $resourceType,
            canonicalDiscriminator: $discriminator,
        );
    }

    public static function unknown(string $providerKey, string $resourceType, string $discriminator): self
    {
        return new self(
            providerKey: $providerKey,
            identityKind: self::Unknown,
            providerResourceType: $resourceType,
            canonicalDiscriminator: $discriminator,
        );
    }

    /**
     * @param  array<string, mixed>  $payload
     */
    public static function fromArray(array $payload): self
    {
        return new self(
            providerKey: (string) ($payload['provider_key'] ?? ''),
            identityKind: (string) ($payload['identity_kind'] ?? ''),
            providerResourceType: self::nullableString($payload['provider_resource_type'] ?? null),
            providerResourceId: self::nullableString($payload['provider_resource_id'] ?? null),
            canonicalDiscriminator: self::nullableString($payload['canonical_discriminator'] ?? null),
        );
    }

    public function stableIdentityValue(): ?string
    {
        return $this->identityKind === self::ProviderResource
            ? $this->providerResourceId
            : $this->canonicalDiscriminator;
    }

    public function fingerprint(): string
    {
        return hash('sha256', json_encode($this->payload(), JSON_THROW_ON_ERROR));
    }

    /**
     * @return array{
     *   provider_key: string,
     *   identity_kind: string,
     *   provider_resource_type: ?string,
     *   provider_resource_id: ?string,
     *   canonical_discriminator: ?string,
     *   fingerprint: string
     * }
     */
    public function toArray(): array
    {
        $payload = $this->payload();

        return $payload + [
            'fingerprint' => hash('sha256', json_encode($payload, JSON_THROW_ON_ERROR)),
        ];
    }

    /**
     * @return array{
     *   provider_key: string,
     *   identity_kind: string,
     *   provider_resource_type: ?string,
     *   provider_resource_id: ?string,
     *   canonical_discriminator: ?string
     * }
     */
    private function payload(): array
    {
        return [
            'provider_key' => $this->providerKey,
            'identity_kind' => $this->identityKind,
            'provider_resource_type' => $this->providerResourceType,
            'provider_resource_id' => $this->providerResourceId,
            'canonical_discriminator' => $this->canonicalDiscriminator,
        ];
    }

    public function jsonSerialize(): array
    {
        return $this->toArray();
    }

    private function assertValid(): void
    {
        if (trim($this->providerKey) === '') {
            throw new InvalidArgumentException('Resource identities require a provider key.');
        }

        if (! in_array($this->identityKind, self::validKinds(), true)) {
            throw new InvalidArgumentException(sprintf('Unsupported resource identity kind [%s].', $this->identityKind));
        }

        if ($this->providerResourceType !== null && trim($this->providerResourceType) === '') {
            throw new InvalidArgumentException('Provider resource type must be non-empty when supplied.');
        }

        if ($this->identityKind === self::ProviderResource) {
            if ($this->providerResourceType === null || trim($this->providerResourceType) === '' || $this->providerResourceId === null || trim($this->providerResourceId) === '') {
                throw new InvalidArgumentException('Provider resource identities require provider resource type and ID.');
            }

            return;
        }

        if ($this->canonicalDiscriminator === null || trim($this->canonicalDiscriminator) === '') {
            throw new InvalidArgumentException('Canonical resource identities require a discriminator.');
        }
    }

    /**
     * @return list<string>
     */
    private static function validKinds(): array
    {
        return [
            self::ProviderResource,
            self::CanonicalBuiltin,
            self::CanonicalDefault,
            self::CanonicalVirtualTarget,
            self::Unsupported,
            self::Unknown,
        ];
    }

    private static function nullableString(mixed $value): ?string
    {
        return is_string($value) && trim($value) !== '' ? trim($value) : null;
    }
}