session-ios/SessionUIKit/Style Guide/Themes/Theme.swift

// Copyright © 2022 Rangeproof Pty Ltd. All rights reserved.

import UIKit.UIColor
import SessionUtilitiesKit

// MARK: - Theme

public enum Theme: String, CaseIterable, Codable, EnumStringSetting {
    case classicDark = "classic_dark"
    case classicLight = "classic_light"
    case oceanDark = "ocean_dark"
    case oceanLight = "ocean_light"
    
    // MARK: - Properties
    
    public var title: String {
        switch self {
            case .classicDark: return "Classic Dark"
            case .classicLight: return "Classic Light"
            case .oceanDark: return "Ocean Dark"
            case .oceanLight: return "Ocean Light"
        }
    }
    
    public var interfaceStyle: UIUserInterfaceStyle {
        switch self {
            case .classicDark, .oceanDark: return .dark
            case .classicLight, .oceanLight: return .light
        }
    }
    
    public var statusBarStyle: UIStatusBarStyle {
        switch self {
            case .classicDark, .oceanDark: return .lightContent
            case .classicLight, .oceanLight: return .darkContent
        }
    }
    
    public var keyboardAppearance: UIKeyboardAppearance {
        switch self {
            case .classicDark, .oceanDark: return .dark
            case .classicLight, .oceanLight: return .default
        }
    }
    
    private var colors: [ThemeValue: UIColor] {
        switch self {
            case .classicDark: return Theme_ClassicDark.theme
            case .classicLight: return Theme_ClassicLight.theme
            case .oceanDark: return Theme_OceanDark.theme
            case .oceanLight: return Theme_OceanLight.theme
        }
    }
    
    public func color(for value: ThemeValue) -> UIColor? {
        switch value {
            case .value(let value, let alpha): return color(for: value)?.withAlphaComponent(alpha)
            
            case .highlighted(let value, let alwaysDarken):
                switch (self.interfaceStyle, alwaysDarken) {
                    case (.light, _), (_, true): return color(for: value)?.brighten(by: -0.06)
                    default: return color(for: value)?.brighten(by: 0.08)
                }
            
            default: return colors[value]
        }
    }
}

// MARK: - ThemeColors

public protocol ThemeColors {
    static var theme: [ThemeValue: UIColor] { get }
}

// MARK: - ThemedNavigation

public protocol ThemedNavigation {
    var navigationBackground: ThemeValue { get }
}

// MARK: - ThemeValue

public indirect enum ThemeValue: Hashable {
    case value(ThemeValue, alpha: CGFloat)
    
    // The 'highlighted' state of a colour will automatically lighten/darken a ThemeValue
    // by a fixed amount depending on wither the theme is dark/light mode
    case highlighted(ThemeValue, alwaysDarken: Bool)
    
    public static func highlighted(_ value: ThemeValue) -> ThemeValue {
        return .highlighted(value, alwaysDarken: false)
    }
    
    // General
    case white
    case black
    case clear
    case primary
    case defaultPrimary
    case danger
    case disabled
    case backgroundPrimary
    case backgroundSecondary
    case textPrimary
    case textSecondary
    case borderSeparator
    
    // Path
    case path_connected
    case path_connecting
    case path_error
    case path_unknown
    
    // TextBox
    case textBox_background
    case textBox_border
    
    // MessageBubble
    case messageBubble_outgoingBackground
    case messageBubble_incomingBackground
    case messageBubble_outgoingText
    case messageBubble_incomingText
    case messageBubble_overlay
    
    // MenuButton
    case menuButton_background
    case menuButton_icon
    case menuButton_outerShadow
    case menuButton_innerShadow
    
    // RadioButton
    case radioButton_selectedBackground
    case radioButton_selectedBackground_disabled
    case radioButton_unselectedBackground
    case radioButton_selectedBorder
    case radioButton_unselectedBorder
    case radioButton_border_disabled
    
    // SessionButton
    case sessionButton_text
    case sessionButton_background
    case sessionButton_highlight
    case sessionButton_border
    case sessionButton_filledText
    case sessionButton_filledBackground
    case sessionButton_filledHighlight
    case sessionButton_destructiveText
    case sessionButton_destructiveBackground
    case sessionButton_destructiveHighlight
    case sessionButton_destructiveBorder
    
    // SolidButton
    case solidButton_background
    
    // Settings
    case settings_tabBackground
    
    // Appearance
    case appearance_sectionBackground
    case appearance_buttonBackground
    
    // Alert
    case alert_text
    case alert_background
    case alert_buttonBackground
    
    // ConversationButton
    case conversationButton_background
    case conversationButton_unreadBackground
    case conversationButton_unreadStripBackground
    case conversationButton_unreadBubbleBackground
    case conversationButton_unreadBubbleText
    case conversationButton_swipeDestructive
    case conversationButton_swipeSecondary
    case conversationButton_swipeTertiary
    
    // InputButton
    case inputButton_background
    
    // ContextMenu
    case contextMenu_background
    case contextMenu_highlight
    case contextMenu_text
    case contextMenu_textHighlight
    
    // Call
    case callAccept_background
    case callDecline_background
    
    // Reactions
    case reactions_contextBackground
    case reactions_contextMoreBackground
    
    // NewConversation
    case newConversation_background
}

// MARK: - ForcedThemeValue

public enum ForcedThemeValue {
    case color(UIColor)
    case primary(Theme.PrimaryColor, alpha: CGFloat?)
    case theme(Theme, color: ThemeValue, alpha: CGFloat?)
    
    public static func primary(_ primary: Theme.PrimaryColor) -> ForcedThemeValue {
        return .primary(primary, alpha: nil)
    }
    
    public static func theme(_ theme: Theme, color: ThemeValue) -> ForcedThemeValue {
        return .theme(theme, color: color, alpha: nil)
    }
}

// MARK: - ForcedThemeAttribute

public enum ForcedThemeAttribute {
    case background(UIColor)
    case foreground(UIColor)
    
    public var key: NSAttributedString.Key {
        switch self {
            case .background: return NSAttributedString.Key.backgroundColor
            case .foreground: return NSAttributedString.Key.foregroundColor
        }
    }
    
    public var value: Any {
        switch self {
            case .background(let value): return value
            case .foreground(let value): return value
        }
    }
}