package document

import (
	"fmt"
	"reflect"
)

// UnmarshalTypeError is an error type representing aa error
// unmarshalling a Smithy document to a Go value type. This is different
// from UnmarshalError in that it does not wrap an underlying error type.
type UnmarshalTypeError struct {
	Value string
	Type  reflect.Type
}

// Error returns the string representation of the error.
// satisfying the error interface
func (e *UnmarshalTypeError) Error() string {
	return fmt.Sprintf("unmarshal failed, cannot unmarshal %s into Go value type %s",
		e.Value, e.Type.String())
}

// An InvalidUnmarshalError is an error type representing an invalid type
// encountered while unmarshalling a Smithy document to a Go value type.
type InvalidUnmarshalError struct {
	Type reflect.Type
}

// Error returns the string representation of the error.
// satisfying the error interface
func (e *InvalidUnmarshalError) Error() string {
	var msg string
	if e.Type == nil {
		msg = "cannot unmarshal to nil value"
	} else if e.Type.Kind() != reflect.Ptr {
		msg = fmt.Sprintf("cannot unmarshal to non-pointer value, got %s", e.Type.String())
	} else {
		msg = fmt.Sprintf("cannot unmarshal to nil value, %s", e.Type.String())
	}

	return fmt.Sprintf("unmarshal failed, %s", msg)
}

// An UnmarshalError wraps an error that occurred while unmarshalling a
// Smithy document into a Go type. This is different from
// UnmarshalTypeError in that it wraps the underlying error that occurred.
type UnmarshalError struct {
	Err   error
	Value string
	Type  reflect.Type
}

// Unwrap returns the underlying unmarshalling error
func (e *UnmarshalError) Unwrap() error {
	return e.Err
}

// Error returns the string representation of the error satisfying the error
// interface.
func (e *UnmarshalError) Error() string {
	return fmt.Sprintf("unmarshal failed, cannot unmarshal %q into %s, %v",
		e.Value, e.Type.String(), e.Err)
}

// An InvalidMarshalError is an error type representing an error
// occurring when marshaling a Go value type.
type InvalidMarshalError struct {
	Message string
}

// Error returns the string representation of the error.
// satisfying the error interface
func (e *InvalidMarshalError) Error() string {
	return fmt.Sprintf("marshal failed, %s", e.Message)
}