const (
	// FileMIMEDirectory is MIME type for directories.
	FileMIMEDirectory = rest.FileMIMEDirectory
)

const (
	// ResourceIDGlob is catch-all identifier for matching every
	// resource from resource group.
	//
	// It can be, for example, used to mark that given user has access
	// to every resource from given group.
	ResourceIDGlob = "*"
)

var (
	// ErrFileNotFound is returned when client requests non-existing file.
	ErrFileNotFound = errors.New("fileserver: file not found")

	// ErrFilenameTaken is returned when file, with given name and the same
	// parent, already exists.
	ErrFilenameTaken = errors.New("fileserver: filemname is already taken")
)

var (
	// ErrUsernameAlreadyTaken is returned when there is already existing user
	// in the system with requested username.
	ErrUsernameAlreadyTaken = errors.New("users: username is already taken")

	// ErrUserNotFound is returned when actions is requested for non-existing user.
	ErrUserNotFound = httpx.NewErrorFromCode(http.StatusNotFound, httpx.ErrorMetadata{
		Message:     "There is no such user in the system.",
		Description: "users: there is no such user",
	})
)

var ErrMissingDependency = errors.New("service: missing dependency")

type AccountCreateRepository interface {
	// AccountCreate creates new account for requested user. It should return
	// ErrUsernameAlreadyTaken error if there is already user with requested
	// username.
	AccountCreate(context.Context, AccountCreateRequest) (*AccountCreateResponse, error)
}

type AccountCreateRequest struct {
	// ID is unique user's identifier.
	ID uuid.UUID

	// Username is unique login name.
	Username string

	// Password is secret hashed phrase use to access user's account.
	Password []byte
}

type AccountCreateResponse struct {
	// CreatedAt is time of account creation.
	CreatedAt time.Time
}

type AccountDeleteRepository interface {
	// AccountDelete removes account and all its dependencies (like files, roles etc), for
	// user with given ID, from the system.
	//
	// This method can return ErrUserNotFound if there is no user with given ID.
	AccountDelete(context.Context, uuid.UUID) error
}

type AccountUpdatePasswordRepository interface {
	// AccountUpdatePassword updates password of existing user.
	//
	// This method can return ErrUserNotFound if there is no user with given ID.
	AccountUpdatePassword(context.Context, AccountUpdatePasswordRequest) error
}

type AccountUpdatePasswordRequest struct {
	// ID is unique user's identifier.
	ID uuid.UUID

	// NewPassword is new hashed password for user.
	NewPassword []byte
}

type AccountsCreateRepository interface {
	// AccountsCreate creates new accounts for requested users. It should return
	// ErrUsernameAlreadyTaken error if there is already user with username from
	// requested batch of users.
	AccountsCreate(context.Context, []AccountCreateRequest) error
}

type AccountsCreator interface {
	AccountCreateRepository
	AccountsCreateRepository
}

type AccountsReadFromRequest struct {
	// Limig is the maximum size of return slice.
	Limit int

	// Last is ID of last user from previous query to AccountsReadFrom method. Every
	// ReadAccountResponse from returned slice belongs to the user that was created
	// after account with Last ID.
	Last uuid.UUID

	// Query is an optional query string. It can be prefix, suffix or substring
	// of username of user that you are looking for.
	Query string
}

type ActivityDecorator struct {
	Pusher      ActivityPusher
	OwnerReader FileOwnerReader
	FileService rest.FileCommandService
	FileReader  FileReadRepository
}

type ActivityPushRequest struct {
	// ID is unique id of new activity record.
	ID uuid.UUID

	// OwnerID is user's ID, which provoked the activity.
	OwnerID uuid.UUID

	// Type of activity record.
	Type string

	// Details consist flat map of key/value records that will be
	// presented to user and system administrator, to provide useful
	// debug informations related to given action.
	Details map[string]any
}

type ActivityPusher interface {
	// ActivityPush saves activity in the storage.
	ActivityPush(context.Context, ActivityPushRequest) error
}

type Admin struct {
	ReadRepository  AdminReadRepository
	WriteRepository AdminWriteRepository
	Registerer      rest.UserRegisterer
}

type AdminReadRepository interface {
	// AdminCount tracks number of admin accounts in the storage.
	AdminCount(context.Context) (int, error)
}

type AdminWriteRepository interface {
	// AdminMakeNow tags user with given ID as admin account with promotion date
	// set to the current time.
	//
	// Admin account can promote other accounts to the admin status. Admin with
	// earlier promotion date cannot withdraw admin permissions. It means that the
	// first Admin can create new admins, but newer admins cannot make the older
	// admin normal again.
	AdminMakeNow(ctx context.Context, id uuid.UUID) error
}

type Auth struct {
	AccountRepository ReadAccountRepository
	ReadRepository    RolesReadRepository
	WriteRepository   RolesWriteRepository
}

type FileCreateWithOwnerRequest struct {
	// ID is unique identifier of the file.
	ID uuid.UUID

	// OwnerID is unique identifier of owner user.
	OwnerID uuid.UUID

	// Parent is optional ID of parent directory. If Parent.Valid is equal to
	// false, then File modelled by FileReadResponse has no parent.
	Parent uuid.NullUUID

	// Name is the name of the file.
	Name string

	// Content of the file.
	Content []byte

	// MIME is MIMEtype of the file.
	MIME string
}

type FileDeleteRepository interface {
	// FileDeleteWithRoles removes file or directory with its children and all
	// roles assigned to the given file. It removes  children roles also in
	// case of directory.
	FileDeleteWithRoles(context.Context, uuid.UUID) error
}

type FileOwnerReader interface {
	// FileOwnerRead returns unique user's ID of owner of file with given file ID.
	FileOwnerRead(ctx context.Context, fileID uuid.UUID) (uuid.UUID, error)
}

type FileReadRepository interface {
	// FileRead returns all the content and metadata associated with file stored
	// in the Okrzeja's storage with given file ID.
	FileRead(ctx context.Context, fileID uuid.UUID) (*FileReadResponse, error)

	// FileReadOfUser returns file data of file owned by user with given username.
	// If there is no such file or user, it returns ErrFileNotFound error.
	FileReadOfUser(ctx context.Context, owner, path string) (*FileReadResponse, error)

	// FilesReadFromDirectory returns all files being stored currently in the directory
	// with provided unique identifier.
	FilesReadFromDirectory(context.Context, uuid.UUID) ([]FileReadResponse, error)
}

type FileReadResponse struct {
	// ID is unique identifier of the file.
	ID uuid.UUID

	// Parent is optional ID of parent directory. If Parent.Valid is equal to
	// false, then File modelled by FileReadResponse has no parent.
	Parent uuid.NullUUID

	// Content of the file.
	Content []byte

	// Name is the name of the file.
	Name string

	// Size is length in bytes for the regular file.
	Size int64

	// MIME is MIMEtype of the file.
	MIME string

	// LastUpdated is datetime when file was updated last time.
	LastUpdated time.Time
}

type FileWriteContentRequest struct {
	// ID is unique identifier of the file.
	ID uuid.UUID

	// Content to be updated.
	Content []byte
}

type FileWriteNameRequest struct {
	// ID is unique identifier of the file.
	ID uuid.UUID

	// Name of the file to be updated.
	Name string
}

type FileWriteRepository interface {
	// FileCreateWithOwner creates new file or directory with provided user ID as owner. It
	// returns ErrFilenameTaken, if there is already file with given name and the same
	// parent ID.
	FileCreateWithOwner(context.Context, FileCreateWithOwnerRequest) error

	// FileWriteContent writes new content to the existing file with provided ID.
	// Returns ErrFileNotFound if there is no file with given ID.
	FileWriteContent(context.Context, FileWriteContentRequest) error

	// FileWriteName updates name of the already existing file with provided ID.
	// Returns ErrFileNotFound if there is no file with given ID.
	FileWriteName(context.Context, FileWriteNameRequest) error
}

type Files struct {
	Reader        FileReadRepository
	Writer        FileWriteRepository
	Deleter       FileDeleteRepository
	AccountReader ReadAccountRepository
}

type PermissionDecorator struct {
	AuthService            *Auth
	WrappedAccountStorage  AccountsCreator
	WrappedAdminRepository AdminWriteRepository
}

type ReadAccountRepository interface {
	// ReadAccount returns account data of user with given unique user ID.
	ReadAccount(ctx context.Context, uid uuid.UUID) (*ReadAccountResponse, error)

	// ReadAccountByUsername returns account data of user with given username.
	ReadAccountByUsername(ctx context.Context, username string) (*ReadAccountResponse, error)

	// AccountsRead returns limited group of accounts.
	//
	// Query is optional query string. See AccountsReadFromRequest for more info about query
	// string.
	AccountsRead(ctx context.Context, limit int, query string) ([]ReadAccountResponse, error)

	// AccountsReadFrom returns limited group of accounts that had been created after creation
	// date of account of user with given ID.
	AccountsReadFrom(ctx context.Context, req AccountsReadFromRequest) ([]ReadAccountResponse, error)
}

type ReadAccountResponse struct {
	// ID is unique user identifier.
	ID uuid.UUID

	// Username is unique username of user.
	Username string

	// Password is hashed password for user's account.
	Password []byte

	// CreatedAt is time of account creation.
	CreatedAt time.Time
}

type Role string

const (
	// RoleOwner marks user as the initial owner of the resource. Owner
	// can read, write, and delete its resource.
	RoleOwner Role = "owner"

	// RoleAdmin marks user as the administrator of the system with
	// all permissions to use given resource, just the same way as
	// RoleOwner.
	RoleAdmin Role = "admin"
)

type RolesReadRepository interface {
	// RolesRead returns slice of roles assigned to given resource and owned
	// by user with provided unique identifier.
	RolesRead(ctx context.Context, req RolesReadRequest) ([]Role, error)
}

type RolesReadRequest struct {
	// ResourceName is the name of resource. It identifies
	// group of roles related to given resource.
	ResourceName string

	// ResourceID is unique identifier of resource. It can alsob be a glob
	// pattern, see ResourceIDGlob.
	ResourceID string

	// UserID is unique identifier of user.
	UserID uuid.UUID
}

type RolesWriteRepository interface {
	// RolesWrite writes rule based on the RolesWriteRequest to the roles storage.
	RolesWrite(context.Context, RolesWriteRequest) error
}

type RolesWriteRequest struct {
	// ResourceName is the name of resource. It identifies
	// group of roles related to given resource.
	ResourceName string

	// ResourceID is unique identifier of resource. It can also be a glob
	// pattern, see ResourceIDGlob.
	ResourceID string

	// Role for given rule.
	Role Role

	// UserID is unique identifier of user.
	UserID uuid.UUID
}

type Users struct {
	AccountCreateRepository
	AccountsCreateRepository
	AccountUpdatePasswordRepository
	AccountDeleteRepository
	ReadAccountRepository
}