defmodule Mix.Tasks.GleamCompile do
  use Mix.Task

  @shortdoc "Compiles Gleam files and copies them to the correct location"
  
  def run(_args) do
    env = Mix.env()
    
    # Check if compile.gleam task exists
    task_exists = Code.ensure_loaded?(Mix.Tasks.Compile.Gleam)
    
    if task_exists do
      # First run the gleam compiler
      Mix.Task.run("compile.gleam")
      
      # Ensure output directory exists
      ebin_dir = "_build/#{env}/lib/aprsme/ebin"
      File.mkdir_p!(ebin_dir)
      
      # Copy beam files from Gleam build to Elixir build
      gleam_output = "build/#{env}/erlang/aprsme/_gleam_artefacts"
      
      if File.exists?(gleam_output) do
        gleam_output
        |> File.ls!()
        |> Enum.filter(&String.ends_with?(&1, ".beam"))
        |> Enum.each(fn beam_file ->
          src = Path.join(gleam_output, beam_file)
          dest = Path.join(ebin_dir, beam_file)
          File.copy!(src, dest)
          Mix.shell().info("Copied #{beam_file}")
        end)
      end
    else
      Mix.shell().info("Gleam compiler not available, compiling manually")
      
      # Compile Gleam files manually using gleam binary if available
      if System.find_executable("gleam") do
        Mix.shell().info("Found gleam binary, compiling...")
        {output, _exit_code} = System.cmd("gleam", ["build"], cd: File.cwd!())
        Mix.shell().info(output)
        
        # Copy from gleam build to elixir build
        # Gleam always builds to dev directory regardless of MIX_ENV
        # The compiled files go to the project's ebin directory
        gleam_output = "build/dev/erlang/aprsme/ebin"
        ebin_dir = "_build/#{env}/lib/aprsme/ebin"
        File.mkdir_p!(ebin_dir)
        
        # First, check if compile.gleam already created the aprsme@encoding.beam
        dev_ebin = "_build/dev/lib/aprsme/ebin"
        if File.exists?(Path.join(dev_ebin, "aprsme@encoding.beam")) do
          Mix.shell().info("Found pre-compiled aprsme@encoding.beam")
          src = Path.join(dev_ebin, "aprsme@encoding.beam")
          dest = Path.join(ebin_dir, "aprsme@encoding.beam")
          File.copy!(src, dest)
          Mix.shell().info("Copied aprsme@encoding.beam to test build")
        end
        
        if File.exists?(gleam_output) do
          Mix.shell().info("Checking #{gleam_output} for beam files...")
          beam_files = gleam_output
          |> File.ls!()
          |> Enum.filter(&String.ends_with?(&1, ".beam"))
          
          Mix.shell().info("Found #{length(beam_files)} beam files")
          
          Enum.each(beam_files, fn beam_file ->
            src = Path.join(gleam_output, beam_file)
            dest = Path.join(ebin_dir, beam_file)
            File.copy!(src, dest)
            Mix.shell().info("Copied #{beam_file} to #{dest}")
          end)
        else
          Mix.shell().info("Gleam output directory #{gleam_output} does not exist")
        end
      else
        # Last resort: try to copy from dev build if available
        dev_ebin = "_build/dev/lib/aprsme/ebin"
        test_ebin = "_build/#{env}/lib/aprsme/ebin"
        
        if File.exists?(dev_ebin) and env != :dev do
          File.mkdir_p!(test_ebin)
          
          dev_ebin
          |> File.ls!()
          |> Enum.filter(&String.starts_with?(&1, "aprs@"))
          |> Enum.each(fn beam_file ->
            src = Path.join(dev_ebin, beam_file)
            dest = Path.join(test_ebin, beam_file)
            File.copy!(src, dest)
          end)
        end
      end
    end
    
    :ok
  end
end