defmodule Mix.Tasks.Firebird.Target.Profile do
  @moduledoc """
  Profile the WASM compilation pipeline for source files.

  Shows detailed timing for each stage of the compilation pipeline,
  helping identify bottlenecks.

  ## Usage

      # Profile a specific file
      mix firebird.target.profile lib/wasm_modules/math.ex

      # Profile with optimizations
      mix firebird.target.profile lib/math.ex --optimize --tco

      # Profile WAT-only compilation
      mix firebird.target.profile lib/math.ex --wat-only

      # JSON output
      mix firebird.target.profile lib/math.ex --json

  ## Example Output

      ⏱ Compilation Profile
        File: lib/wasm_modules/math.ex
        Module: MyMath
        Status: ✅ Success

        read           12μs   0.3%
        parse         156μs   3.8%
        ir_gen        892μs  21.7%
        optimize       45μs   1.1%
        validate       23μs   0.6%
        type_infer    567μs  13.8%
        wat_gen       234μs   5.7%
        wat2wasm     2187μs  53.2% ██████████████████████████

        Total: 4116μs
  """

  use Mix.Task

  @shortdoc "Profile the WASM compilation pipeline"

  @switches [
    optimize: :boolean,
    tco: :boolean,
    inline: :boolean,
    wat_only: :boolean,
    json: :boolean
  ]

  @impl Mix.Task
  def run(args) do
    {opts, paths, _} = OptionParser.parse(args, switches: @switches)

    if Enum.empty?(paths) do
      Mix.raise("Usage: mix firebird.target.profile <file.ex> [options]")
    end

    pipeline_opts = Keyword.take(opts, [:optimize, :tco, :inline, :wat_only])
    json_mode = Keyword.get(opts, :json, false)

    Enum.each(paths, fn path ->
      unless File.regular?(path) do
        Mix.raise("File not found: #{path}")
      end

      {:ok, profile} = Firebird.Target.Profiler.profile_file(path, pipeline_opts)

      if json_mode do
        data = %{
          file: profile.file,
          module: if(profile.module, do: to_string(profile.module)),
          result: profile.result,
          total_us: profile.total_us,
          timings:
            Enum.map(profile.timings, fn t ->
              %{
                stage: t.stage,
                elapsed_us: t.elapsed_us,
                percentage: Float.round(t.percentage, 2)
              }
            end),
          error: if(profile.error, do: inspect(profile.error)),
          options: Enum.into(profile.options, %{})
        }

        Mix.shell().info(Jason.encode!(data, pretty: true))
      else
        Mix.shell().info(Firebird.Target.Profiler.format(profile))
      end
    end)

    :ok
  end
end