defmodule Mix.Tasks.OpenResponses.Compliance do
  @moduledoc """
  Run the Open Responses upstream compliance suite against a running server.

  ## Usage

  Start your server in one terminal:

      PHX_SERVER=true MIX_ENV=test mix phx.server

  Then in another terminal:

      mix open_responses.compliance

  By default, targets `http://localhost:4000/v1`. Pass `--base-url` to
  target a different host:

      mix open_responses.compliance --base-url http://staging.example.com/v1

  ## Prerequisites

  Requires [Bun](https://bun.sh) and a clone of the compliance test runner.
  The task will clone the runner into `tmp/compliance` if it is not present.

  Alternatively, point the official interactive tester at your running server:
  https://www.openresponses.org/compliance

  ## Options

  - `--base-url` — base URL of the server under test (default: http://localhost:4000/v1)
  - `--api-key` — API key to pass in the Authorization header (default: empty)
  - `--filter` — comma-separated list of test case IDs to run
  """

  use Mix.Task

  @repo_url "https://github.com/openresponses/openresponses.git"
  @clone_dir "tmp/compliance"
  @shortdoc "Run the Open Responses compliance suite against a server"

  @impl Mix.Task
  def run(args) do
    {opts, _rest, _invalid} =
      OptionParser.parse(args,
        strict: [base_url: :string, api_key: :string, filter: :string]
      )

    base_url = Keyword.get(opts, :base_url, "http://localhost:4000/v1")
    api_key = Keyword.get(opts, :api_key, "")
    filter = Keyword.get(opts, :filter)

    ensure_bun!()
    ensure_clone!()

    cmd_args = build_args(base_url, api_key, filter)

    Mix.shell().info("Running compliance suite against #{base_url} ...")

    case System.cmd("bun", cmd_args,
           cd: @clone_dir,
           into: IO.stream(:stdio, :line),
           stderr_to_stdout: true
         ) do
      {_, 0} ->
        Mix.shell().info("Compliance suite passed.")

      {_, code} ->
        Mix.raise("Compliance suite exited with code #{code}.")
    end
  end

  defp ensure_bun! do
    case System.find_executable("bun") do
      nil -> Mix.raise("Bun is required. Install it from https://bun.sh")
      _ -> :ok
    end
  end

  defp ensure_clone! do
    unless File.dir?(@clone_dir) do
      Mix.shell().info("Cloning compliance runner into #{@clone_dir} ...")
      File.mkdir_p!("tmp")

      case System.cmd("git", ["clone", "--depth", "1", @repo_url, @clone_dir],
             stderr_to_stdout: true
           ) do
        {_, 0} ->
          System.cmd("bun", ["install"], cd: @clone_dir, stderr_to_stdout: true)

        {output, code} ->
          Mix.raise("git clone failed (exit #{code}):\n#{output}")
      end
    end
  end

  defp build_args(base_url, api_key, filter) do
    base = ["run", "bin/compliance-tests.ts", "--base-url", base_url, "--api-key", api_key]
    if filter, do: base ++ ["--filter", filter], else: base
  end
end