package weed_server

import (
	"context"
	"encoding/json"

	"github.com/seaweedfs/seaweedfs/weed/credential"
	"github.com/seaweedfs/seaweedfs/weed/glog"
	"github.com/seaweedfs/seaweedfs/weed/pb/iam_pb"
	"github.com/seaweedfs/seaweedfs/weed/s3api/policy_engine"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
)

// IamGrpcServer implements the IAM gRPC service on the filer
type IamGrpcServer struct {
	iam_pb.UnimplementedSeaweedIdentityAccessManagementServer
	credentialManager *credential.CredentialManager
}

// NewIamGrpcServer creates a new IAM gRPC server
func NewIamGrpcServer(credentialManager *credential.CredentialManager) *IamGrpcServer {
	return &IamGrpcServer{
		credentialManager: credentialManager,
	}
}

//////////////////////////////////////////////////
// Configuration Management

func (s *IamGrpcServer) GetConfiguration(ctx context.Context, req *iam_pb.GetConfigurationRequest) (*iam_pb.GetConfigurationResponse, error) {
	glog.V(4).Infof("GetConfiguration")

	if s.credentialManager == nil {
		return nil, status.Errorf(codes.FailedPrecondition, "credential manager is not configured")
	}

	config, err := s.credentialManager.LoadConfiguration(ctx)
	if err != nil {
		glog.Errorf("Failed to load configuration: %v", err)
		return nil, err
	}

	return &iam_pb.GetConfigurationResponse{
		Configuration: config,
	}, nil
}

func (s *IamGrpcServer) PutConfiguration(ctx context.Context, req *iam_pb.PutConfigurationRequest) (*iam_pb.PutConfigurationResponse, error) {
	glog.V(4).Infof("PutConfiguration")

	if s.credentialManager == nil {
		return nil, status.Errorf(codes.FailedPrecondition, "credential manager is not configured")
	}

	if req.Configuration == nil {
		return nil, status.Errorf(codes.InvalidArgument, "configuration is nil")
	}

	err := s.credentialManager.SaveConfiguration(ctx, req.Configuration)
	if err != nil {
		glog.Errorf("Failed to save configuration: %v", err)
		return nil, err
	}

	return &iam_pb.PutConfigurationResponse{}, nil
}

//////////////////////////////////////////////////
// User Management

func (s *IamGrpcServer) CreateUser(ctx context.Context, req *iam_pb.CreateUserRequest) (*iam_pb.CreateUserResponse, error) {
	if req == nil || req.Identity == nil {
		return nil, status.Errorf(codes.InvalidArgument, "identity is required")
	}
	glog.V(4).Infof("CreateUser: %s", req.Identity.Name)

	if s.credentialManager == nil {
		return nil, status.Errorf(codes.FailedPrecondition, "credential manager is not configured")
	}

	err := s.credentialManager.CreateUser(ctx, req.Identity)
	if err != nil {
		if err == credential.ErrUserAlreadyExists {
			return nil, status.Errorf(codes.AlreadyExists, "user %s already exists", req.Identity.Name)
		}
		glog.Errorf("Failed to create user %s: %v", req.Identity.Name, err)
		return nil, status.Errorf(codes.Internal, "failed to create user: %v", err)
	}

	return &iam_pb.CreateUserResponse{}, nil
}

func (s *IamGrpcServer) GetUser(ctx context.Context, req *iam_pb.GetUserRequest) (*iam_pb.GetUserResponse, error) {
	glog.V(4).Infof("GetUser: %s", req.Username)

	if s.credentialManager == nil {
		return nil, status.Errorf(codes.FailedPrecondition, "credential manager is not configured")
	}

	identity, err := s.credentialManager.GetUser(ctx, req.Username)
	if err != nil {
		if err == credential.ErrUserNotFound {
			return nil, status.Errorf(codes.NotFound, "user %s not found", req.Username)
		}
		glog.Errorf("Failed to get user %s: %v", req.Username, err)
		return nil, status.Errorf(codes.Internal, "failed to get user: %v", err)
	}

	return &iam_pb.GetUserResponse{
		Identity: identity,
	}, nil
}

func (s *IamGrpcServer) UpdateUser(ctx context.Context, req *iam_pb.UpdateUserRequest) (*iam_pb.UpdateUserResponse, error) {
	glog.V(4).Infof("UpdateUser: %s", req.Username)
	if req == nil || req.Identity == nil {
		return nil, status.Errorf(codes.InvalidArgument, "identity is required")
	}

	if s.credentialManager == nil {
		return nil, status.Errorf(codes.FailedPrecondition, "credential manager is not configured")
	}

	err := s.credentialManager.UpdateUser(ctx, req.Username, req.Identity)
	if err != nil {
		if err == credential.ErrUserNotFound {
			return nil, status.Errorf(codes.NotFound, "user %s not found", req.Username)
		}
		glog.Errorf("Failed to update user %s: %v", req.Username, err)
		return nil, status.Errorf(codes.Internal, "failed to update user: %v", err)
	}

	return &iam_pb.UpdateUserResponse{}, nil
}

func (s *IamGrpcServer) DeleteUser(ctx context.Context, req *iam_pb.DeleteUserRequest) (*iam_pb.DeleteUserResponse, error) {
	glog.V(4).Infof("DeleteUser: %s", req.Username)

	if s.credentialManager == nil {
		return nil, status.Errorf(codes.FailedPrecondition, "credential manager is not configured")
	}

	err := s.credentialManager.DeleteUser(ctx, req.Username)
	if err != nil {
		if err == credential.ErrUserNotFound {
			// Deleting a non-existent user is generally considered a success or Not Found depending on semantics
			// In S3 API, usually idempotent. But for Admin API, often 404.
			// Here we return NotFound to let client decide, but traditionally delete is idempotent.
			// However, if we want strict status codes:
			return nil, status.Errorf(codes.NotFound, "user %s not found", req.Username)
		}
		glog.Errorf("Failed to delete user %s: %v", req.Username, err)
		return nil, status.Errorf(codes.Internal, "failed to delete user: %v", err)
	}

	return &iam_pb.DeleteUserResponse{}, nil
}

func (s *IamGrpcServer) ListUsers(ctx context.Context, req *iam_pb.ListUsersRequest) (*iam_pb.ListUsersResponse, error) {
	glog.V(4).Infof("ListUsers")

	if s.credentialManager == nil {
		return nil, status.Errorf(codes.FailedPrecondition, "credential manager is not configured")
	}

	usernames, err := s.credentialManager.ListUsers(ctx)
	if err != nil {
		glog.Errorf("Failed to list users: %v", err)
		return nil, err
	}

	return &iam_pb.ListUsersResponse{
		Usernames: usernames,
	}, nil
}

//////////////////////////////////////////////////
// Access Key Management

func (s *IamGrpcServer) CreateAccessKey(ctx context.Context, req *iam_pb.CreateAccessKeyRequest) (*iam_pb.CreateAccessKeyResponse, error) {
	if req == nil || req.Credential == nil {
		return nil, status.Errorf(codes.InvalidArgument, "credential is required")
	}
	glog.V(4).Infof("CreateAccessKey for user: %s", req.Username)

	if s.credentialManager == nil {
		return nil, status.Errorf(codes.FailedPrecondition, "credential manager is not configured")
	}

	err := s.credentialManager.CreateAccessKey(ctx, req.Username, req.Credential)
	if err != nil {
		if err == credential.ErrUserNotFound {
			return nil, status.Errorf(codes.NotFound, "user %s not found", req.Username)
		}
		glog.Errorf("Failed to create access key for user %s: %v", req.Username, err)
		return nil, status.Errorf(codes.Internal, "failed to create access key: %v", err)
	}

	return &iam_pb.CreateAccessKeyResponse{}, nil
}

func (s *IamGrpcServer) DeleteAccessKey(ctx context.Context, req *iam_pb.DeleteAccessKeyRequest) (*iam_pb.DeleteAccessKeyResponse, error) {
	glog.V(4).Infof("DeleteAccessKey: %s for user: %s", req.AccessKey, req.Username)

	if s.credentialManager == nil {
		return nil, status.Errorf(codes.FailedPrecondition, "credential manager is not configured")
	}

	err := s.credentialManager.DeleteAccessKey(ctx, req.Username, req.AccessKey)
	if err != nil {
		if err == credential.ErrUserNotFound {
			return nil, status.Errorf(codes.NotFound, "user %s not found", req.Username)
		}
		if err == credential.ErrAccessKeyNotFound {
			return nil, status.Errorf(codes.NotFound, "access key %s not found", req.AccessKey)
		}
		glog.Errorf("Failed to delete access key %s for user %s: %v", req.AccessKey, req.Username, err)
		return nil, status.Errorf(codes.Internal, "failed to delete access key: %v", err)
	}

	return &iam_pb.DeleteAccessKeyResponse{}, nil
}

func (s *IamGrpcServer) GetUserByAccessKey(ctx context.Context, req *iam_pb.GetUserByAccessKeyRequest) (*iam_pb.GetUserByAccessKeyResponse, error) {
	glog.V(4).Infof("GetUserByAccessKey: %s", req.AccessKey)

	if s.credentialManager == nil {
		return nil, status.Errorf(codes.FailedPrecondition, "credential manager is not configured")
	}

	identity, err := s.credentialManager.GetUserByAccessKey(ctx, req.AccessKey)
	if err != nil {
		if err == credential.ErrAccessKeyNotFound {
			return nil, status.Errorf(codes.NotFound, "access key %s not found", req.AccessKey)
		}
		glog.Errorf("Failed to get user by access key %s: %v", req.AccessKey, err)
		return nil, status.Errorf(codes.Internal, "failed to get user: %v", err)
	}

	return &iam_pb.GetUserByAccessKeyResponse{
		Identity: identity,
	}, nil
}

//////////////////////////////////////////////////
// Policy Management

func (s *IamGrpcServer) PutPolicy(ctx context.Context, req *iam_pb.PutPolicyRequest) (*iam_pb.PutPolicyResponse, error) {
	glog.V(4).Infof("PutPolicy: %s", req.Name)

	if s.credentialManager == nil {
		return nil, status.Errorf(codes.FailedPrecondition, "credential manager is not configured")
	}

	if req.Name == "" {
		return nil, status.Errorf(codes.InvalidArgument, "policy name is required")
	}
	if req.Content == "" {
		return nil, status.Errorf(codes.InvalidArgument, "policy content is required")
	}

	var policy policy_engine.PolicyDocument
	if err := json.Unmarshal([]byte(req.Content), &policy); err != nil {
		glog.Errorf("Failed to unmarshal policy %s: %v", req.Name, err)
		return nil, err
	}

	err := s.credentialManager.PutPolicy(ctx, req.Name, policy)
	if err != nil {
		glog.Errorf("Failed to put policy %s: %v", req.Name, err)
		return nil, err
	}

	return &iam_pb.PutPolicyResponse{}, nil
}

func (s *IamGrpcServer) GetPolicy(ctx context.Context, req *iam_pb.GetPolicyRequest) (*iam_pb.GetPolicyResponse, error) {
	glog.V(4).Infof("GetPolicy: %s", req.Name)

	if s.credentialManager == nil {
		return nil, status.Errorf(codes.FailedPrecondition, "credential manager is not configured")
	}

	policy, err := s.credentialManager.GetPolicy(ctx, req.Name)
	if err != nil {
		glog.Errorf("Failed to get policy %s: %v", req.Name, err)
		return nil, err
	}

	if policy == nil {
		return nil, status.Errorf(codes.NotFound, "policy %s not found", req.Name)
	}

	jsonBytes, err := json.Marshal(policy)
	if err != nil {
		glog.Errorf("Failed to marshal policy %s: %v", req.Name, err)
		return nil, err
	}

	return &iam_pb.GetPolicyResponse{
		Name:    req.Name,
		Content: string(jsonBytes),
	}, nil
}

func (s *IamGrpcServer) ListPolicies(ctx context.Context, req *iam_pb.ListPoliciesRequest) (*iam_pb.ListPoliciesResponse, error) {
	glog.V(4).Infof("ListPolicies")

	if s.credentialManager == nil {
		return nil, status.Errorf(codes.FailedPrecondition, "credential manager is not configured")
	}

	policiesData, err := s.credentialManager.GetPolicies(ctx)
	if err != nil {
		glog.Errorf("Failed to list policies: %v", err)
		return nil, err
	}

	var policies []*iam_pb.Policy
	for name, policy := range policiesData {
		jsonBytes, err := json.Marshal(policy)
		if err != nil {
			return nil, status.Errorf(codes.Internal, "failed to marshal policy %s: %v", name, err)
		}
		policies = append(policies, &iam_pb.Policy{
			Name:    name,
			Content: string(jsonBytes),
		})
	}

	return &iam_pb.ListPoliciesResponse{
		Policies: policies,
	}, nil
}

func (s *IamGrpcServer) DeletePolicy(ctx context.Context, req *iam_pb.DeletePolicyRequest) (*iam_pb.DeletePolicyResponse, error) {
	glog.V(4).Infof("DeletePolicy: %s", req.Name)

	if s.credentialManager == nil {
		return nil, status.Errorf(codes.FailedPrecondition, "credential manager is not configured")
	}

	err := s.credentialManager.DeletePolicy(ctx, req.Name)
	if err != nil {
		glog.Errorf("Failed to delete policy %s: %v", req.Name, err)
		return nil, err
	}

	return &iam_pb.DeletePolicyResponse{}, nil
}