deepcat

#!/usr/bin/env ruby

require 'optparse'
require 'set'
require 'uri'
require 'find'
require 'pathname'

# Initialize options
options = {
  depth: 2
}

# Create OptionParser
parser = OptionParser.new do |opts|
  opts.banner = "Usage: deepcat [options] FILES_OR_DIRECTORIES..."

  opts.on("-d", "--depth DEPTH", Integer, "Set the recursion depth for linked files (default: 2)") do |d|
    options[:depth] = d
  end

  opts.on("-h", "--help", "Prints this help") do
    puts opts
    exit
  end
end

# Function to convert full paths to relative paths
def relative_path(path, cwd)
  Pathname.new(path).relative_path_from(cwd).to_s
end

begin
  # Parse options
  parser.parse!

  if ARGV.empty?
    puts parser
    exit
  end
rescue OptionParser::InvalidOption => e
  warn e.message
  puts parser
  exit 1
end

# Function to extract markdown links and GitBook includes from a file
def extract_links(file_path)
  links = []
  File.readlines(file_path, encoding: 'UTF-8').each do |line|
    # Extract markdown-style links
    line.scan(/\[.*?\]\((.*?)\)/).each do |match|
      link = match.first.strip
      link = link.split('#').first.strip
      next if link.empty?

      uri = URI.parse(link)
      if uri.scheme == 'http' || uri.scheme == 'https' || uri.scheme == 'ftp'
        next
      end

      links << link
    rescue URI::InvalidURIError
      links << link
    end

    # Extract GitBook-style includes
    line.scan(/{%\s*include\s*"([^"]+)"\s*%}/).each do |match|
      link = match.first.strip
      next if link.empty?
      links << link
    end
  end
  links
end

# Function to resolve relative paths
def resolve_path(base_path, relative_path)
  File.expand_path(relative_path, File.dirname(base_path))
end

# Function to recursively find markdown files in directories
def find_markdown_files(paths)
  markdown_files = Set.new
  paths.each do |path|
    if File.file?(path) && path =~ /\.md$/i
      markdown_files.add(File.expand_path(path))
    elsif File.directory?(path)
      Find.find(path) do |p|
        if File.file?(p) && p =~ /\.md$/i
          markdown_files.add(File.expand_path(p))
        end
      end
    else
      warn "Warning: #{path} is neither a file nor a directory."
    end
  end
  markdown_files
end

# Function to process a single file and its references
def process_file_references(file_path, depth_limit, referenced_files, file_depths)
  processing_queue = [[file_path, 0]]

  while !processing_queue.empty?
    current_file, current_depth = processing_queue.shift
    next if current_depth > depth_limit
    next if referenced_files.include?(current_file) && current_file != file_path

    referenced_files.add(current_file)
    file_depths[current_file] = [file_depths[current_file] || Float::INFINITY, current_depth].min

    begin
      links = extract_links(current_file)
    rescue Errno::ENOENT
      warn "Warning: File not found - #{current_file}"
      next
    end

    links.each do |link|
      next if link.nil? || link.empty?

      link_path = link.split('#').first
      next if link_path.nil? || link_path.empty?
      next if link_path =~ /^\s*(http|https|ftp):\/\//

      # Handle both absolute and relative paths
      linked_path = if link_path.start_with?('/')
        File.join(Dir.pwd, link_path)
      else
        resolve_path(current_file, link_path)
      end

      if File.file?(linked_path) && linked_path =~ /\.md$/i
        processing_queue << [linked_path, current_depth + 1]
      elsif File.directory?(linked_path)
        readme_path = File.join(linked_path, 'README.md')
        if File.file?(readme_path)
          processing_queue << [readme_path, current_depth + 1]
        else
          warn "Warning: No README.md found in directory - #{relative_path(linked_path, Pathname.new(Dir.pwd))}"
        end
      else
        warn "Warning: Cannot process link - #{relative_path(linked_path, Pathname.new(Dir.pwd))}"
      end
    end
  end
end

# Get current working directory
cwd = Pathname.new(Dir.pwd)

# Process all input files and their references
referenced_files = Set.new
file_depths = {}

# First, find all markdown files from the arguments
initial_files = find_markdown_files(ARGV)

# Then process each file's references
initial_files.each do |file|
  process_file_references(file, options[:depth], referenced_files, file_depths)
end

# Sort files by their minimum depth and then alphabetically
files_to_include = referenced_files.to_a.sort_by { |f| [file_depths[f], f] }

# Get the first file from ARGV that exists and is a markdown file
first_argv_file = ARGV.find do |path|
  expanded_path = File.expand_path(path)
  File.file?(expanded_path) && expanded_path =~ /\.md$/i
end

# Print list of files to stderr with paths relative to cwd
warn "Files to include:"
if first_argv_file
  first_file_path = File.expand_path(first_argv_file)

  # Print first file at the beginning
  depth_marker = "↴" * file_depths[first_file_path]
  warn "#{depth_marker} #{relative_path(first_file_path, cwd)}".strip

  if files_to_include.size > 1
    # Print other files
    files_to_include.each do |file|
      next if file == first_file_path
      depth_marker = "↴" * file_depths[file]
      warn "#{depth_marker} #{relative_path(file, cwd)}".strip
    end

    # Print first file again at the end
    depth_marker = "↴" * file_depths[first_file_path]
    warn "#{depth_marker} #{relative_path(first_file_path, cwd)}".strip
  end
else
  # If no valid markdown file was found in ARGV, print files as normal
  files_to_include.each do |file|
    depth_marker = "↴" * file_depths[file]
    warn "#{depth_marker} #{relative_path(file, cwd)}".strip
  end
end

# Function to print file content with header using relative paths
def print_file(file, cwd)
  relative_file = relative_path(file, cwd)
  puts "<!-- BEGIN #{relative_file} -->"
  begin
    puts File.read(file, encoding: 'UTF-8')
  rescue Errno::ENOENT
    warn "Warning: File not found - #{relative_file}"
  end
  puts "<!-- END #{relative_file} -->"
end

# Print the actual file contents
if first_argv_file
  first_file_path = File.expand_path(first_argv_file)

  # Print the first file
  print_file(first_file_path, cwd)

  if files_to_include.size > 1
    # Print all files except the first ARGV file
    files_to_include.each do |file|
      next if file == first_file_path
      print_file(file, cwd)
    end

    # Print the first file again
    print_file(first_file_path, cwd)
  end
else
  # If no valid markdown file was found in ARGV, print files as normal
  files_to_include.each do |file|
    print_file(file, cwd)
  end
end