package action

import (
	"errors"
	"go.uber.org/zap/zapcore"
	"hexmap-server/state"
)

// ErrNoTransparentColors is returned when a user tries to set their active color or a cell color to transparent.
// Transparent here is defined as having an alpha component of less than 15 (0xF).
var ErrNoTransparentColors error = errors.New("transparent colors not allowed")

// UserActiveColor is the action sent when the user's current color, the one being painted with, changes.
type UserActiveColor struct {
	// Color is the color that is now active.
	Color state.HexColor `json:"color"`
}

func (c UserActiveColor) MarshalLogObject(encoder zapcore.ObjectEncoder) error {
	encoder.AddString("color", c.Color.String())
	return nil
}

// Apply sets the user's active color, or returns ErrNoOp if it can't.
func (c UserActiveColor) Apply(s *state.Synced) error {
	if c.Color.A < 0xF {
		return ErrNoTransparentColors
	}
	if s.User.ActiveColor == c.Color {
		return ErrNoOp
	}
	s.User.ActiveColor = c.Color
	return nil
}