elixir mix task version of harper reed's feb 2025 llm workflow

ai.ex

# Harper's post: https://harper.blog/2025/02/16/my-llm-codegen-workflow-atm/
#
# I mostly copied his file based workflow here
#
defmodule Mix.Tasks.Ai do
  use Mix.Task

  @shortdoc "AI-assisted development workflow tasks"

  @moduledoc """
  AI-assisted development workflow tasks for code analysis and automation.
  
  ## Usage
  
      mix ai <subcommand> [options]
  
  ## Available Subcommands
  
  ### Bundle Management
  
      mix ai clean           # Clean old bundles and generate fresh repomix output
      mix ai copy            # Copy bundle to clipboard for external LLM use
  
  ### Code Analysis
  
      mix ai review          # Generate code review prompt + bundle (clipboard)
      mix ai tests           # Generate missing tests prompt + bundle (clipboard)  
      mix ai readme          # Generate README prompt + bundle (clipboard)
  
  ### Issue Management
  
      mix ai issues          # Generate GitHub issues prompt + bundle (clipboard)
      mix ai issues.gen      # Interactive GitHub issues generation workflow
      mix ai issues.post     # Post issues from issues.txt via gh CLI
      mix ai prompts         # Generate issue prompts + bundle (clipboard)
  
  ## Examples
  
      mix ai clean           # Clean and regenerate bundle
      mix ai copy            # Copy bundle to clipboard
      mix ai review          # Get code review prompt ready for LLM
      mix ai issues.gen      # Full workflow: prompt → LLM → save → post
  
  ## Files Used
  
  - `repomix-output.txt` - Generated bundle file
  - `issues.txt` - LLM-generated issues for posting
  
  ## Requirements
  
  - `repomix` installed for bundle generation
  - `gh` CLI for GitHub issue posting
  - Clipboard access (pbcopy/pbpaste)
  """

  @valid_subcommands ~w[clean copy review tests readme issues issues.gen issues.post prompts help]

  def run([]), do: run(["help"])
  
  def run(["help"]) do
    Mix.shell().info(@moduledoc)
  end

  def run([subcommand | args]) when subcommand in @valid_subcommands do
    case subcommand do
      "clean" -> clean_bundles(args)
      "copy" -> copy_bundle(args)
      "review" -> generate_review_prompt(args)
      "tests" -> generate_tests_prompt(args)
      "readme" -> generate_readme_prompt(args)
      "issues" -> generate_issues_prompt(args)
      "issues.gen" -> generate_issues_workflow(args)
      "issues.post" -> post_issues(args)
      "prompts" -> generate_issue_prompts(args)
    end
  end

  def run([invalid_subcommand | _]) do
    Mix.shell().error("Unknown subcommand: #{invalid_subcommand}")
    Mix.shell().info("Valid subcommands: #{Enum.join(@valid_subcommands, ", ")}")
    Mix.shell().info("Run `mix ai help` for detailed usage information.")
  end

  # Clean old bundles and regenerate
  defp clean_bundles(_args) do
    Mix.shell().info("Cleaning old bundles...")
    
    # Clean up old files
    File.rm("repomix-output.txt")
    File.rm("code-bundle.txt")
    
    # Generate new bundle
    case System.cmd("repomix", ["--output", "repomix-output.txt"]) do
      {_output, 0} ->
        Mix.shell().info("✓ Fresh bundle generated: repomix-output.txt")
      {error, _} ->
        Mix.shell().error("Failed to generate bundle: #{error}")
    end
  end

  # Copy bundle to clipboard
  defp copy_bundle(_args) do
    if File.exists?("repomix-output.txt") do
      case System.cmd("bash", ["-c", "cat repomix-output.txt | pbcopy"]) do
        {_, 0} ->
          Mix.shell().info("✓ Bundle copied to clipboard")
        {error, _} ->
          Mix.shell().error("Failed to copy to clipboard: #{error}")
      end
    else
      Mix.shell().error("Bundle not found. Run `mix ai clean` first.")
    end
  end

  # Generate code review prompt
  defp generate_review_prompt(_args) do
    prompt = """
    Please review this codebase for:
    - Code quality and best practices
    - Potential bugs and security issues
    - Performance improvements
    - Architecture suggestions
    - Testing coverage gaps
    
    Focus on actionable feedback with specific examples.
    
    """
    
    copy_prompt_with_bundle(prompt, "Code review prompt + bundle copied to clipboard")
  end

  # Generate missing tests prompt
  defp generate_tests_prompt(_args) do
    prompt = """
    Analyze this Elixir/Phoenix codebase and identify missing test coverage.
    
    Please generate test cases for:
    - Untested functions and modules
    - Edge cases and error conditions
    - Integration scenarios
    - LiveView interactions
    - API endpoints
    
    Follow ExUnit best practices and existing test patterns.
    
    """
    
    copy_prompt_with_bundle(prompt, "Missing tests prompt + bundle copied to clipboard")
  end

  # Generate README prompt
  defp generate_readme_prompt(_args) do
    prompt = """
    Generate a comprehensive README.md for this Elixir/Phoenix project.
    
    Include:
    - Project overview and purpose
    - Key features and architecture
    - Installation and setup instructions
    - Usage examples and API documentation
    - Development workflow
    - Contributing guidelines
    - Deployment information
    
    Base the content on the actual codebase structure and functionality.
    
    """
    
    copy_prompt_with_bundle(prompt, "README generation prompt + bundle copied to clipboard")
  end

  # Generate GitHub issues prompt
  defp generate_issues_prompt(_args) do
    prompt = """
    Based on this codebase, generate 3-5 GitHub issues for bugs, features, and improvements.
    
    Format each issue as:
    
    TITLE: [Clear, concise title]
    BODY: [Detailed description with acceptance criteria]  
    LABELS: [Comma-separated labels like 'bug', 'enhancement', 'documentation']
    
    ---
    
    Focus on:
    - Actual bugs or potential issues you can identify
    - Meaningful feature enhancements
    - Documentation improvements
    - Performance optimizations
    - Code quality improvements
    
    """
    
    copy_prompt_with_bundle(prompt, "GitHub issues prompt + bundle copied to clipboard")
  end

  # Generate issue prompts
  defp generate_issue_prompts(_args) do
    prompt = """
    Generate detailed issue prompts for this codebase covering:
    
    1. Bug reports for potential issues
    2. Feature requests for enhancements
    3. Documentation improvements needed
    4. Testing requirements and gaps
    5. Performance optimization opportunities
    6. Security considerations
    7. Code quality improvements
    
    Make each prompt specific and actionable.
    
    """
    
    copy_prompt_with_bundle(prompt, "Issue prompts + bundle copied to clipboard")
  end

  # Interactive GitHub issues workflow
  defp generate_issues_workflow(_args) do
    prompt = """
    Based on this codebase, generate 3-5 GitHub issues for bugs, features, and improvements.
    
    Format each issue as:
    
    TITLE: [Clear, concise title]
    BODY: [Detailed description with acceptance criteria]
    LABELS: [Comma-separated labels like 'bug', 'enhancement', 'documentation']
    
    ---
    
    """
    
    if File.exists?("repomix-output.txt") do
      bundle = File.read!("repomix-output.txt")
      full_prompt = prompt <> "\n" <> bundle
      
      temp_file = "/tmp/ai_prompt_#{:rand.uniform(99999)}.txt"
      File.write!(temp_file, full_prompt)
      
      case System.cmd("bash", ["-c", "cat #{temp_file} | pbcopy"]) do
        {_, 0} ->
          File.rm(temp_file)
          Mix.shell().info("✓ Issues generation prompt + bundle copied to clipboard")
          Mix.shell().info("")
          Mix.shell().info("Next steps:")
          Mix.shell().info("1. Paste into your LLM")
          Mix.shell().info("2. Save the LLM response as 'issues.txt'")
          Mix.shell().info("3. Run: mix ai issues.post")
        {error, _} ->
          File.rm(temp_file)
          Mix.shell().error("Failed to copy to clipboard: #{error}")
      end
    else
      Mix.shell().error("Bundle not found. Run `mix ai clean` first.")
    end
  end

  # Post issues from issues.txt via gh CLI
  defp post_issues(_args) do
    if File.exists?("issues.txt") do
      Mix.shell().info("Posting GitHub issues...")
      
      case System.cmd("bash", ["priv/scripts/post_issues.sh"]) do
        {output, 0} ->
          Mix.shell().info("✓ Issues posted successfully!")
          Mix.shell().info(output)
        {error, _} ->
          Mix.shell().error("Failed to post issues: #{error}")
      end
    else
      Mix.shell().error("issues.txt not found. Run `mix ai issues.gen` first.")
    end
  end

  # Helper to copy prompt + bundle to clipboard
  defp copy_prompt_with_bundle(prompt, success_message) do
    if File.exists?("repomix-output.txt") do
      bundle = File.read!("repomix-output.txt")
      full_content = prompt <> "\n" <> bundle
      
      temp_file = "/tmp/ai_content_#{:rand.uniform(99999)}.txt"
      File.write!(temp_file, full_content)
      
      case System.cmd("bash", ["-c", "cat #{temp_file} | pbcopy"]) do
        {_, 0} ->
          File.rm(temp_file)
          Mix.shell().info("✓ #{success_message}")
        {error, _} ->
          File.rm(temp_file)
          Mix.shell().error("Failed to copy to clipboard: #{error}")
      end
    else
      Mix.shell().error("Bundle not found. Run `mix ai clean` first.")
    end
  end
end