# typed: strict
# frozen_string_literal: true

require "yaml"

module Tapioca
  module ConfigHelper
    extend T::Sig
    extend T::Helpers

    requires_ancestor { Thor }

    sig { returns(String) }
    attr_reader :command_name

    sig { returns(Thor::CoreExt::HashWithIndifferentAccess) }
    attr_reader :defaults

    sig { params(args: T.untyped, local_options: T.untyped, config: T.untyped).void }
    def initialize(args = [], local_options = {}, config = {})
      # Store current command
      command = config[:current_command]
      command_options = config[:command_options]
      @command_name = T.let(command.name, String)
      @merged_options = T.let(nil, T.nilable(Thor::CoreExt::HashWithIndifferentAccess))
      @defaults = T.let(Thor::CoreExt::HashWithIndifferentAccess.new, Thor::CoreExt::HashWithIndifferentAccess)

      # Filter command options unless we are handling the help command.
      # This is so that the defaults are printed
      filter_defaults(command_options) unless command_name == "help"

      super
    end

    sig { returns(Thor::CoreExt::HashWithIndifferentAccess) }
    def options
      @merged_options ||= begin
        original_options = super
        config_options = config_options(original_options)

        merge_options(defaults, config_options, original_options)
      end
    end

    private

    sig { params(options: T::Hash[Symbol, Thor::Option]).void }
    def filter_defaults(options)
      options.each do |key, option|
        # Store the value of the current default in our defaults hash
        defaults[key] = option.default
        # Remove the default value from the option
        option.instance_variable_set(:@default, nil)
      end
    end

    sig { params(options: Thor::CoreExt::HashWithIndifferentAccess).returns(Thor::CoreExt::HashWithIndifferentAccess) }
    def config_options(options)
      config_file = options[:config]
      config = {}

      if File.exist?(config_file)
        config = YAML.load_file(config_file, fallback: {})
      end

      validate_config!(config_file, config)

      Thor::CoreExt::HashWithIndifferentAccess.new(config[command_name] || {})
    end

    sig { params(config_file: String, config: T::Hash[T.untyped, T.untyped]).void }
    def validate_config!(config_file, config)
      # To ensure that this is not re-entered, we mark during validation
      return if @validating_config
      @validating_config = T.let(true, T.nilable(T::Boolean))

      commands = T.cast(self, Thor).class.commands

      errors = config.flat_map do |config_key, config_options|
        command = commands[config_key.to_s]

        unless command
          next build_error("unknown key `#{config_key}`")
        end

        validate_config_options(command.options, config_key, config_options || {})
      end.compact

      unless errors.empty?
        print_errors(config_file, errors)
        exit(1)
      end
    ensure
      @validating_config = false
    end

    sig do
      params(
        command_options: T::Hash[Symbol, Thor::Option],
        config_key: String,
        config_options: T::Hash[T.untyped, T.untyped]
      ).returns(T::Array[ConfigError])
    end
    def validate_config_options(command_options, config_key, config_options)
      config_options.map do |config_option_key, config_option_value|
        command_option = command_options[config_option_key.to_sym]

        unless command_option
          next build_error("unknown option `#{config_option_key}` for key `#{config_key}`")
        end

        config_option_value_type = case config_option_value
        when FalseClass, TrueClass
          :boolean
        when Numeric
          :numeric
        when Hash
          :hash
        when Array
          :array
        when String
          :string
        else
          :object
        end

        unless config_option_value_type == command_option.type
          next build_error("invalid value for option `#{config_option_key}` for key `#{config_key}` " \
            "- expected `#{command_option.type.capitalize}` but found #{config_option_value_type.capitalize}")
        end
      end.compact
    end

    class ConfigErrorMessagePart < T::Struct
      const :message, String
      const :colors, T::Array[Symbol]
    end

    class ConfigError < T::Struct
      const :message_parts, T::Array[ConfigErrorMessagePart]
    end

    sig { params(msg: String).returns(ConfigError) }
    def build_error(msg)
      parts = msg.split(/(`[^`]+` ?)/)

      message_parts = parts.map do |part|
        match = part.match(/`([^`]+)`( ?)/)

        if match
          ConfigErrorMessagePart.new(
            message: "#{match[1]}#{match[2]}",
            colors: [:bold, :blue]
          )
        else
          ConfigErrorMessagePart.new(
            message: part,
            colors: [:yellow]
          )
        end
      end

      ConfigError.new(
        message_parts: message_parts
      )
    end

    sig { params(config_file: String, errors: T::Array[ConfigError]).void }
    def print_errors(config_file, errors)
      say_error("\nConfiguration file ", :red)
      say_error("#{config_file} ", :blue, :bold)
      say_error("has the following errors:\n\n", :red)

      errors.each do |error|
        say_error("- ")
        error.message_parts.each do |part|
          T.unsafe(self).say_error(part.message, *part.colors)
        end
      end
    end

    sig do
      params(options: T.nilable(Thor::CoreExt::HashWithIndifferentAccess))
        .returns(Thor::CoreExt::HashWithIndifferentAccess)
    end
    def merge_options(*options)
      merged = options.each_with_object({}) do |option, result|
        result.merge!(option || {}) do |_, this_val, other_val|
          if this_val.is_a?(Hash) && other_val.is_a?(Hash)
            Thor::CoreExt::HashWithIndifferentAccess.new(this_val.merge(other_val))
          else
            other_val
          end
        end
      end

      Thor::CoreExt::HashWithIndifferentAccess.new(merged)
    end
  end
end