package authmethods

import (
	"context"
	"errors"
	"fmt"
	"regexp"
	"strings"

	"github.com/hashicorp/boundary/internal/auth"
	"github.com/hashicorp/boundary/internal/auth/password"
	"github.com/hashicorp/boundary/internal/auth/password/store"
	"github.com/hashicorp/boundary/internal/db"
	pb "github.com/hashicorp/boundary/internal/gen/controller/api/resources/authmethods"
	pbs "github.com/hashicorp/boundary/internal/gen/controller/api/services"
	"github.com/hashicorp/boundary/internal/servers/controller/handlers"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
	"google.golang.org/protobuf/types/known/wrapperspb"
)

var (
	maskManager handlers.MaskManager
	reInvalidID = regexp.MustCompile("[^A-Za-z0-9]")
)

func init() {
	var err error
	if maskManager, err = handlers.NewMaskManager(&store.AuthMethod{}, &pb.AuthMethod{}, &pb.PasswordAuthMethodAttributes{}); err != nil {
		panic(err)
	}
}

// Service handles request as described by the pbs.AuthMethodServiceServer interface.
type Service struct {
	repoFn func() (*password.Repository, error)
}

// NewService returns a auth method service which handles auth method related requests to boundary.
func NewService(repo func() (*password.Repository, error)) (Service, error) {
	if repo == nil {
		return Service{}, fmt.Errorf("nil iam repository provided")
	}
	return Service{repoFn: repo}, nil
}

var _ pbs.AuthMethodServiceServer = Service{}

// ListAuthMethods implements the interface pbs.AuthMethodServiceServer.
func (s Service) ListAuthMethods(ctx context.Context, req *pbs.ListAuthMethodsRequest) (*pbs.ListAuthMethodsResponse, error) {
	authResults := auth.Verify(ctx)
	if authResults.Error != nil {
		return nil, authResults.Error
	}
	if err := validateListRequest(req); err != nil {
		return nil, err
	}
	ul, err := s.listFromRepo(ctx, authResults.Scope.GetId())
	if err != nil {
		return nil, err
	}
	for _, item := range ul {
		item.Scope = authResults.Scope
	}
	return &pbs.ListAuthMethodsResponse{Items: ul}, nil
}

// GetAuthMethods implements the interface pbs.AuthMethodServiceServer.
func (s Service) GetAuthMethod(ctx context.Context, req *pbs.GetAuthMethodRequest) (*pbs.GetAuthMethodResponse, error) {
	authResults := auth.Verify(ctx)
	if authResults.Error != nil {
		return nil, authResults.Error
	}
	if err := validateGetRequest(req); err != nil {
		return nil, err
	}
	u, err := s.getFromRepo(ctx, req.GetId())
	if err != nil {
		return nil, err
	}
	u.Scope = authResults.Scope
	return &pbs.GetAuthMethodResponse{Item: u}, nil
}

// CreateAuthMethod implements the interface pbs.AuthMethodServiceServer.
func (s Service) CreateAuthMethod(ctx context.Context, req *pbs.CreateAuthMethodRequest) (*pbs.CreateAuthMethodResponse, error) {
	authResults := auth.Verify(ctx)
	if authResults.Error != nil {
		return nil, authResults.Error
	}
	if err := validateCreateRequest(req); err != nil {
		return nil, err
	}
	u, err := s.createInRepo(ctx, authResults.Scope.GetId(), req.GetItem())
	if err != nil {
		return nil, err
	}
	u.Scope = authResults.Scope
	return &pbs.CreateAuthMethodResponse{Item: u, Uri: fmt.Sprintf("scopes/%s/auth-methods/%s", authResults.Scope.GetId(), u.GetId())}, nil
}

// UpdateAuthMethod implements the interface pbs.AuthMethodServiceServer.
func (s Service) UpdateAuthMethod(ctx context.Context, req *pbs.UpdateAuthMethodRequest) (*pbs.UpdateAuthMethodResponse, error) {
	authResults := auth.Verify(ctx)
	if authResults.Error != nil {
		return nil, authResults.Error
	}
	if err := validateUpdateRequest(req); err != nil {
		return nil, err
	}
	u, err := s.updateInRepo(ctx, authResults.Scope.GetId(), req.GetId(), req.GetVersion(), req.GetUpdateMask().GetPaths(), req.GetItem())
	if err != nil {
		return nil, err
	}
	u.Scope = authResults.Scope
	return &pbs.UpdateAuthMethodResponse{Item: u}, nil
}

// DeleteAuthMethod implements the interface pbs.AuthMethodServiceServer.
func (s Service) DeleteAuthMethod(ctx context.Context, req *pbs.DeleteAuthMethodRequest) (*pbs.DeleteAuthMethodResponse, error) {
	authResults := auth.Verify(ctx)
	if authResults.Error != nil {
		return nil, authResults.Error
	}
	if err := validateDeleteRequest(req); err != nil {
		return nil, err
	}
	existed, err := s.deleteFromRepo(ctx, req.GetId())
	if err != nil {
		return nil, err
	}
	return &pbs.DeleteAuthMethodResponse{Existed: existed}, nil
}

func (s Service) getFromRepo(ctx context.Context, id string) (*pb.AuthMethod, error) {
	repo, err := s.repoFn()
	if err != nil {
		return nil, err
	}
	u, err := repo.LookupAuthMethod(ctx, id)
	if err != nil {
		if errors.Is(err, db.ErrRecordNotFound) {
			return nil, handlers.NotFoundErrorf("AuthMethod %q doesn't exist.", id)
		}
		return nil, err
	}
	if u == nil {
		return nil, handlers.NotFoundErrorf("AuthMethod %q doesn't exist.", id)
	}
	return toProto(u)
}

func (s Service) listFromRepo(ctx context.Context, scopeId string) ([]*pb.AuthMethod, error) {
	repo, err := s.repoFn()
	if err != nil {
		return nil, err
	}
	ul, err := repo.ListAuthMethods(ctx, scopeId)
	if err != nil {
		return nil, err
	}
	var outUl []*pb.AuthMethod
	for _, u := range ul {
		ou, err := toProto(u)
		if err != nil {
			return nil, err
		}
		outUl = append(outUl, ou)
	}
	return outUl, nil
}

func (s Service) createInRepo(ctx context.Context, scopeId string, item *pb.AuthMethod) (*pb.AuthMethod, error) {
	var opts []password.Option
	if item.GetName() != nil {
		opts = append(opts, password.WithName(item.GetName().GetValue()))
	}
	if item.GetDescription() != nil {
		opts = append(opts, password.WithDescription(item.GetDescription().GetValue()))
	}
	u, err := password.NewAuthMethod(scopeId, opts...)
	if err != nil {
		return nil, status.Errorf(codes.Internal, "Unable to build auth method for creation: %v.", err)
	}
	repo, err := s.repoFn()
	if err != nil {
		return nil, err
	}
	out, err := repo.CreateAuthMethod(ctx, u)
	if err != nil {
		return nil, status.Errorf(codes.Internal, "Unable to create auth method: %v.", err)
	}
	if out == nil {
		return nil, status.Error(codes.Internal, "Unable to create auth method but no error returned from repository.")
	}
	return toProto(out)
}

func (s Service) updateInRepo(ctx context.Context, scopeId, id string, version uint32, mask []string, item *pb.AuthMethod) (*pb.AuthMethod, error) {
	var opts []password.Option
	if desc := item.GetDescription(); desc != nil {
		opts = append(opts, password.WithDescription(desc.GetValue()))
	}
	if name := item.GetName(); name != nil {
		opts = append(opts, password.WithName(name.GetValue()))
	}
	u, err := password.NewAuthMethod(scopeId, opts...)
	if err != nil {
		return nil, status.Errorf(codes.Internal, "Unable to build auth method for update: %v.", err)
	}

	pwAttrs := &pb.PasswordAuthMethodAttributes{}
	if err := handlers.StructToProto(item.GetAttributes(), pwAttrs); err != nil {
		return nil, status.Errorf(codes.InvalidArgument, "Provided attributes don't match expected format.")
	}
	if pwAttrs.GetMinLoginNameLength() != 0 {
		u.MinLoginNameLength = pwAttrs.GetMinLoginNameLength()
	}
	if pwAttrs.GetMinPasswordLength() != 0 {
		u.MinPasswordLength = pwAttrs.GetMinPasswordLength()
	}

	u.PublicId = id
	dbMask := maskManager.Translate(mask)
	if len(dbMask) == 0 {
		return nil, handlers.InvalidArgumentErrorf("No valid fields included in the update mask.", map[string]string{"update_mask": "No valid paths provided in the update mask."})
	}
	repo, err := s.repoFn()
	if err != nil {
		return nil, err
	}
	out, rowsUpdated, err := repo.UpdateAuthMethod(ctx, u, version, dbMask)
	if err != nil {
		return nil, status.Errorf(codes.Internal, "Unable to update auth method: %v.", err)
	}
	if rowsUpdated == 0 {
		return nil, handlers.NotFoundErrorf("AuthMethod %q doesn't exist.", id)
	}
	return toProto(out)
}

func (s Service) deleteFromRepo(ctx context.Context, id string) (bool, error) {
	repo, err := s.repoFn()
	if err != nil {
		return false, err
	}
	rows, err := repo.DeleteAuthMethod(ctx, id)
	if err != nil {
		if errors.Is(err, db.ErrRecordNotFound) {
			return false, nil
		}
		return false, status.Errorf(codes.Internal, "Unable to delete auth method: %v.", err)
	}
	return rows > 0, nil
}

func toProto(in *password.AuthMethod) (*pb.AuthMethod, error) {
	out := pb.AuthMethod{
		Id:          in.GetPublicId(),
		CreatedTime: in.GetCreateTime().GetTimestamp(),
		UpdatedTime: in.GetUpdateTime().GetTimestamp(),
		Version:     in.GetVersion(),
		Type:        "password",
	}
	if in.GetDescription() != "" {
		out.Description = wrapperspb.String(in.GetDescription())
	}
	if in.GetName() != "" {
		out.Name = wrapperspb.String(in.GetName())
	}
	st, err := handlers.ProtoToStruct(&pb.PasswordAuthMethodAttributes{
		MinLoginNameLength: in.GetMinLoginNameLength(),
		MinPasswordLength:  in.GetMinPasswordLength(),
	})
	if err != nil {
		return nil, status.Errorf(codes.Internal, "failed building password attribute struct: %v", err)
	}
	out.Attributes = st
	return &out, nil
}

// A validateX method should exist for each method above.  These methods do not make calls to any backing service but enforce
// requirements on the structure of the request.  They verify that:
//  * The path passed in is correctly formatted
//  * All required parameters are set
//  * There are no conflicting parameters provided
func validateGetRequest(req *pbs.GetAuthMethodRequest) error {
	badFields := map[string]string{}
	if !validId(req.GetId(), password.AuthMethodPrefix+"_") {
		badFields["id"] = "Invalid formatted id."
	}
	if len(badFields) > 0 {
		return handlers.InvalidArgumentErrorf("Improperly formatted identifier.", badFields)
	}
	return nil
}

func validateListRequest(req *pbs.ListAuthMethodsRequest) error {
	badFields := map[string]string{}
	if len(badFields) > 0 {
		return handlers.InvalidArgumentErrorf("Improperly formatted identifier.", badFields)
	}
	return nil
}

func validateCreateRequest(req *pbs.CreateAuthMethodRequest) error {
	badFields := map[string]string{}
	item := req.GetItem()
	if item.GetId() != "" {
		badFields["id"] = "This is a read only field."
	}
	if item.GetCreatedTime() != nil {
		badFields["created_time"] = "This is a read only field."
	}
	if item.GetUpdatedTime() != nil {
		badFields["updated_time"] = "This is a read only field."
	}
	switch item.GetType() {
	case "password":
		pwAttrs := &pb.PasswordAuthMethodAttributes{}
		if err := handlers.StructToProto(item.GetAttributes(), pwAttrs); err != nil {
			badFields["attributes"] = "Attribute fields do not match the expected format."
		}
	default:
		badFields["type"] = "This is a required field and must be \"password\"."
	}
	if len(badFields) > 0 {
		return handlers.InvalidArgumentErrorf("Argument errors found in the request.", badFields)
	}
	return nil
}

func validateUpdateRequest(req *pbs.UpdateAuthMethodRequest) error {
	badFields := map[string]string{}
	if !validId(req.GetId(), password.AuthMethodPrefix+"_") {
		badFields["id"] = "Improperly formatted identifier."
	}
	if req.GetUpdateMask() == nil {
		badFields["update_mask"] = "UpdateMask not provided but is required to update this resource."
	}
	if req.GetVersion() == 0 {
		badFields["version"] = "Existing resource version is required for an update."
	}

	item := req.GetItem()
	if item == nil {
		// It is legitimate for no item to be specified in an update request as it indicates all fields provided in
		// the mask will be marked as unset.
		return nil
	}
	if item.GetId() != "" {
		badFields["id"] = "This is a read only field and cannot be specified in an update request."
	}
	if item.GetCreatedTime() != nil {
		badFields["created_time"] = "This is a read only field and cannot be specified in an update request."
	}
	if item.GetUpdatedTime() != nil {
		badFields["updated_time"] = "This is a read only field and cannot be specified in an update request."
	}
	if item.GetType() != "" {
		badFields["type"] = "This is a read only field and cannot be specified in an update request."
	}
	if len(badFields) > 0 {
		return handlers.InvalidArgumentErrorf("Errors in provided fields.", badFields)
	}

	return nil
}

func validateDeleteRequest(req *pbs.DeleteAuthMethodRequest) error {
	badFields := map[string]string{}
	if !validId(req.GetId(), password.AuthMethodPrefix+"_") {
		badFields["id"] = "Incorrectly formatted identifier."
	}
	if len(badFields) > 0 {
		return handlers.InvalidArgumentErrorf("Errors in provided fields.", badFields)
	}
	return nil
}

func validId(id, prefix string) bool {
	if !strings.HasPrefix(id, prefix) {
		return false
	}
	id = strings.TrimPrefix(id, prefix)
	return !reInvalidID.Match([]byte(id))
}