package settings

import "strings"

const (
	MinReadingSpeed = 100
	MaxReadingSpeed = 1000

	MinFontSize = 24
	MaxFontSize = 96

	ThemeDark  = "dark"
	ThemeLight = "light"
)

// Settings contains user preferences.
type Settings struct {
	ReadingSpeed int    `json:"readingSpeed"`
	FontSize     int    `json:"fontSize"`
	Theme        string `json:"theme"`
}

// Default returns the default application settings.
func Default() Settings {
	return Settings{
		ReadingSpeed: 300,
		FontSize:     48,
		Theme:        ThemeDark,
	}
}

// Validate checks whether all settings contain supported values.
func (s Settings) Validate() bool {
	return s.ReadingSpeed >= MinReadingSpeed &&
		s.ReadingSpeed <= MaxReadingSpeed &&
		s.FontSize >= MinFontSize &&
		s.FontSize <= MaxFontSize &&
		(s.Theme == ThemeDark || s.Theme == ThemeLight)
}

// Normalize returns settings with values restricted to supported options.
func (s Settings) Normalize() Settings {
	defaults := Default()

	if s.ReadingSpeed < MinReadingSpeed {
		s.ReadingSpeed = MinReadingSpeed
	} else if s.ReadingSpeed > MaxReadingSpeed {
		s.ReadingSpeed = MaxReadingSpeed
	}

	if s.FontSize < MinFontSize {
		s.FontSize = MinFontSize
	} else if s.FontSize > MaxFontSize {
		s.FontSize = MaxFontSize
	}

	s.Theme = strings.ToLower(strings.TrimSpace(s.Theme))

	if s.Theme != ThemeDark && s.Theme != ThemeLight {
		s.Theme = defaults.Theme
	}

	return s
}