yamly

type CollectionState interface {
	// Size returns elements amount in the complex node.
	Size() int
	// HasUnprocessedItems shows if Decoder has not processed any element of the complex node yet.
	HasUnprocessedItems() bool
}

type Decoder interface {
	// TryNull returns a boolean value indicating if current node is null node.
	// If it is null, proceeds to the next node.
	TryNull() bool

	// Integer extracts an integer value of given bit size from current text node.
	// If current node is not a text node or its value does not represent integer,
	// a ErrDenied error is stored in Decoder.
	Integer(bitSize int) int64

	// Unsigned extracts an unsigned integer value of given bit size from current text node.
	// If current node is not a text node or its value does not represent unsigned integer,
	// a ErrDenied error is stored in Decoder.
	Unsigned(bitSize int) uint64

	// Boolean extracts a boolean value of given bit size from current text node.
	// If current node is not a text node or its value does not represent boolean,
	// a ErrDenied error is stored in Decoder.
	Boolean() bool

	// Float extracts a float value of given bit size from current text node.
	// If current node is not a text node or its value does not represent float,
	// a ErrDenied error is stored in Decoder.
	Float(bitSize int) float64

	// String extracts a string value of given bit size from current text node.
	// If current node is not a text node, a ErrDenied error is stored in Decoder.
	String() string

	// Timestamp extracts a time.Time value of given bit size from current text node.
	// If current node is not a text node or its value does not represent date,
	// a ErrDenied error is stored in Decoder.
	Timestamp() time.Time

	// Sequence expects a sequence node in AST and returns a CollectionState associated with it.
	// If Decoder meets unexpected node (e.g. text or mapping), a ErrDenied error is stored in Decoder.
	Sequence() CollectionState

	// Mapping expects a mapping node in AST and returns a CollectionState associated with it.
	// If Decoder meets unexpected node (e.g. text or sequence), a ErrDenied error is stored in Decoder.
	Mapping() CollectionState

	// Any converts current subtree into Go value and returns it.
	Any() any

	// Raw serializes and returns current subtree as bytes.
	Raw() []byte

	// Skip skips current subtree and proceeds to the next.
	Skip()

	// Error returns a stored error.
	Error() error

	// AddError allows to add custom error to Decoder.
	AddError(err error)
}

type Encoder interface {
	Inserter

	// EncodeToString encodes the AST builded with Inserter methods as a string.
	EncodeToString() (string, error)
	// EncodeToBytes encodes the AST builded with Inserter methods as a byte slice.
	EncodeToBytes() ([]byte, error)
	// EncodeTo encodes the AST builded with Inserter methods and writes the serialized data into given io.Writer.
	EncodeTo(dst io.Writer) error
}

type ExtendedDecoder[T any] interface {
	Decoder

	// Node returns current subtree.
	Node() T
}

type Inserter interface {
	// InsertInteger inserts an integer into AST as text node
	InsertInteger(int64)

	// InsertUnsigned inserts an unsigned integer into AST as text node.
	InsertUnsigned(uint64)

	// InsertBoolean inserts a boolean value into AST as text node.
	InsertBoolean(bool)

	// InsertFloat inserts a float value into AST as text node.
	InsertFloat(float64)

	// InsertString inserts a string value into AST as text node.
	InsertString(string)

	// InsertTimestamp inserts a time.Time value into AST as text node.
	InsertTimestamp(time.Time)

	// InsertNull inserts a null node into AST.
	InsertNull()

	// StartSequence creates a sequence node in AST.
	// Until EndSequence is called, every inserted node will be inserted as sequence element.
	StartSequence()
	// EndSequence finishes a sequence created before with StartSequence.
	// If current node is not a sequence (i.e. StartSequence was not called or nested mapping/sequence is not finished),
	// an error is added to inserter.
	EndSequence()

	// StartMapping creates a mapping node in AST.
	// Until EndMapping is called, every odd inserted node will be inserted as mapping entry key
	// and every even inserted node will be inserted as mapping entry value.
	StartMapping()
	// EndMapping finished a mapping created before with StartMapping.
	// If current node is not a sequence (i.e. StartMapping was not called or nested mapping/sequence is not finished),
	// or there is a pending mapping entry (with created key and absent value),
	// an error is added to inserter
	EndMapping()

	// InsertRaw inserts given raw bytes in YAML as subtree into AST.
	// Also, it accepts an error to make it comfortable to call Marshaler.MarshalYAML to provide arguments.
	InsertRaw([]byte, error)
	// InsertRawText inserts given raw bytes as text node into AST.
	// Also, it accepts an error to make it comfortable to call encoding.TextMarshaler methods to provide arguments.
	InsertRawText([]byte, error)
}

type MarshalerYamly interface {
	MarshalYamly(Inserter)
}

type TreeBuilder[T any] interface {
	Inserter
	// Result returns the AST builded with Inserter methods.
	Result() (T, error)
}

type TreeWriter[T any] interface {
	// WriteTo serializes given tree and writes serialized bytes into given io.Writer.
	WriteTo(dst io.Writer, tree T) error
	// WriteString serializes given tree as string.
	WriteString(tree T) (string, error)
	// WriteBytes serializes given tree as bytes.
	WriteBytes(tree T) ([]byte, error)
}

type UnknownFieldError struct {
	Field string
}

type UnmarshalerYamly interface {
	UnmarshalYamly(Decoder)
}