# vim: set ts=2 sw=2 et ft=crystal:

require "file"
require "option_parser"

# The CodePreloader module organizes classes and methods related to preloading code files.
module CodePreloader
  # The Cli class handles command-line interface operations for the CodePreloader.
  class Cli
    getter repository_path : String?
    getter ignore_list : Array(String) = [] of String
    getter output_file_path : String?
    getter header_prompt_file_path : String? # Add type annotation
    getter footer_prompt_file_path : String? # Assuming you'll also need this

    # Initializes the Cli class with default values.
    def initialize
      @repository_path = ""
      @output_file_path = ""
    end

    # Parses command-line arguments and initializes the necessary configurations.
    def parse_arguments(args : Array(String))
      OptionParser.parse(args) do |parser|
        parser.banner = "Usage: code-preloader [options] ROOT_DIR"

        parser.on("-c CONFIG_FILE", "--config=CONFIG_FILE", "Load parameters from CONFIG_FILE") do |config_file|
          load_config(config_file)
        end

        parser.on("-i IGNORE_PATH", "--ignore=IGNORE_PATH", "Ignore file or directory") do |ignore_file|
          @ignore_list << ignore_file
        end

        parser.on("-o OUTPUT_FILE", "--output=OUTPUT_FILE", "Write output to OUTPUT_FILE") do |output_file|
          @output_file_path = output_file
        end

        parser.on("--header-prompt=HEADER_PROMPT_FILE", "Load header prompt from HEADER_PROMPT_FILE") do |header_prompt_file|
          @header_prompt_file_path = header_prompt_file
        end

        parser.on("--footer-prompt=FOOTER_PROMPT_FILE", "Load footer prompt from FOOTER_PROMPT_FILE") do |footer_prompt_file|
          @footer_prompt_file_path = footer_prompt_file
        end

        parser.on("-h", "--help", "Show this help") do
          STDERR.puts parser
          exit
        end

        parser.unknown_args do |remaining_args, _|
          if remaining_args.size != 1
            abort("Invalid number of arguments. Expected exactly one argument for ROOT_DIR.")
          end
          @repository_path = remaining_args[0]
        end
      end

      validate_arguments
    end

      # Executes the main functionality of the CLI application.
    def exec
      header_prompt = ""
      footer_prompt = ""
      __header_prompt_file_path = @header_prompt_file_path
      __footer_prompt_file_path = @footer_prompt_file_path

      if !__header_prompt_file_path.nil?
        STDERR.puts "Loading header prompt from: #{__header_prompt_file_path}"
        header_prompt = File.read(__header_prompt_file_path)
      end

      if !__footer_prompt_file_path.nil?
        STDERR.puts "Loading footer prompt from: #{__footer_prompt_file_path}"
        footer_prompt = File.read(__footer_prompt_file_path)
      end

      STDERR.puts "Processing repository: #{repository_path}"

      __output_file_path = @output_file_path
      __repository_path = @repository_path 

      abort("@output_file_path should be non-nil here") if __output_file_path.nil?
      abort("@repository_path should be non-nil here") if __repository_path.nil?

      invalid_output_file = true
      output_file = STDOUT

      unless __output_file_path.nil? || __output_file_path.try(&.empty?) || (__output_file_path != "-")
        output_file = File.open(__output_file_path, "w")
        invalid_output_file = false
      end 

      output_file.puts header_prompt if header_prompt_file_path

      process_repository(__repository_path, output_file)

      output_file.puts footer_prompt if footer_prompt_file_path

      output_file.close if !invalid_output_file
      STDERR.puts "Processing completed. Output written to: #{invalid_output_file ? "stdout" : __output_file_path}"

    rescue e : Exception
      STDERR.puts "An error occurred during execution: #{e.message}"
      exit(1)
    end

    # Processes the specified repository and writes the output to a file.
    def process_repository(repository_path : String, output_file : IO::FileDescriptor)

      process_directory(repository_path, output_file)

    rescue e : IO::Error
      STDERR.puts "Error processing repository: #{e.message}"
      exit(1)
    end

    private def process_directory(path : String, output_file : IO::FileDescriptor)
      Dir.each_child(path) do |child|
        child_path = File.join(path, child)

        ignores = (
          ignore_list
          .map{ |prefix| [prefix, File.expand_path(child_path) =~ /^#{File.expand_path(prefix)}/] }
          .reject!{ |item| item[1].nil? }
        )
        next if !ignores.empty?
        
        STDERR.puts "File: #{child_path}"
        child_path = File.join(path, child)
        if File.directory?(child_path)
          process_directory(child_path, output_file)
        else
          process_file(child_path, output_file)
        end
      end
    end

    private def process_file(file_path : String, output_file : IO::FileDescriptor)
      __repository_path = @repository_path
      abort("@repository_path should be non-nil here") if __repository_path.nil?

      relative_file_path = file_path.sub(/^#{Regex.escape(__repository_path)}/, ".").lstrip
      output_file.puts "@@ File \"#{relative_file_path}\""
      output_file.puts ""
      output_file.puts(File.read(file_path))
      output_file.puts ""
    end

    private def preamble_text : String
      local_preamble_file_path = @preamble_file_path
      return "" if local_preamble_file_path.nil?

      File.read(local_preamble_file_path)
    rescue e : IO::Error
      STDERR.puts "Error reading preamble file: #{e.message}"
      exit(1)
    end

    private def validate_arguments
      abort("Missing repository path.") if @repository_path.nil? || @repository_path.try(&.empty?)
      abort("Missing repository path.") if 
      STDERR.puts("Output file path not specified (using STDOUT)") if @output_file_path.nil? || @output_file_path.try(&.empty?)
    end

    # Reads and returns a list of paths to ignore from the given file.
    def self.get_ignore_list(ignore_file_path : String) : Array(String)
      File.exists?(ignore_file_path) ? File.read_lines(ignore_file_path).map(&.strip) : [] of String
    rescue e : IO::Error
      STDERR.puts "Error reading ignore file: #{e.message}"
      exit(1)
    end

    # Loads configuration from a config file.
    private def load_config(config_file_path : String)
      # Implement configuration loading logic here
    end
  end
end