# frozen_string_literal: true

require "pastel"

module Clacky
  module UI2
    module Themes
      # BaseTheme defines the abstract interface for all themes
      # Subclasses MUST define SYMBOLS and COLORS constants
      class BaseTheme
        def initialize
          @pastel = Pastel.new
          @is_dark_background = nil  # Will be set by ThemeManager
          validate_theme_definition!
        end

        # Set background mode (called by ThemeManager after detection)
        # @param is_dark [Boolean] true if dark background, false if light
        def set_background_mode(is_dark)
          @is_dark_background = is_dark
        end

        # Get all symbols defined by this theme
        # @return [Hash] Symbol definitions
        def symbols
          self.class::SYMBOLS
        end

        # Get all colors defined by this theme
        # @return [Hash] Color definitions
        def colors
          self.class::COLORS
        end

        # Get symbol for a specific key
        # @param key [Symbol] Symbol key
        # @return [String] Symbol string
        def symbol(key)
          symbols[key] || "[??]"
        end

        # Get symbol color for a specific key
        # @param key [Symbol] Color key
        # @return [Symbol] Pastel color method name
        def symbol_color(key)
          colors.dig(key, 0) || :white
        end

        # Get text color for a specific key
        # Automatically selects appropriate color based on terminal background
        # Color format: [symbol_color, dark_bg_text_color, light_bg_text_color]
        # @param key [Symbol] Color key
        # @return [Symbol] Pastel color method name
        def text_color(key)
          color_def = colors[key]
          return :white unless color_def
          
          # Use index 1 for dark background, index 2 for light background
          dark_background? ? color_def[1] : color_def[2]
        end

        # Format symbol with its color
        # @param key [Symbol] Symbol key (e.g., :user, :assistant)
        # @return [String] Colored symbol
        def format_symbol(key)
          @pastel.public_send(symbol_color(key), symbol(key))
        end

        # Format text with color for given key
        # @param text [String] Text to format
        # @param key [Symbol] Color key (e.g., :user, :assistant)
        # @return [String] Colored text
        def format_text(text, key)
          @pastel.public_send(text_color(key), text)
        end

        # Theme name for display (subclasses should override)
        # @return [String] Theme name
        def name
          raise NotImplementedError, "Subclass must implement #name method"
        end

        # Check if terminal has dark background
        # Uses pre-detected value from ThemeManager, or defaults to true
        # @return [Boolean] true if dark background, false if light background
        def dark_background?
          # Use pre-detected value if available, otherwise default to dark
          @is_dark_background.nil? ? true : @is_dark_background
        end


        # Validate that subclass has defined required constants
        def validate_theme_definition!
          unless self.class.const_defined?(:SYMBOLS)
            raise NotImplementedError, "Theme #{self.class.name} must define SYMBOLS constant"
          end

          unless self.class.const_defined?(:COLORS)
            raise NotImplementedError, "Theme #{self.class.name} must define COLORS constant"
          end
        end
      end
    end
  end
end