defmodule Mix.Tasks.Firebird.Analyze do
  @moduledoc """
  Analyze Elixir source files for WASM compilability.

  Shows which functions can be compiled, estimates complexity,
  and provides optimization suggestions.

  ## Usage

      mix firebird.analyze lib/wasm_modules/math.ex
      mix firebird.analyze lib/wasm_modules/

  ## Output

  For each file, shows:
  - Module name
  - Function list with compilability status
  - Recursion analysis (tail-recursive, exponential, etc.)
  - Optimization suggestions
  """

  use Mix.Task

  @shortdoc "Analyze Elixir files for WASM compilability"

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

    if Enum.empty?(paths) do
      Mix.raise("No input files specified. Usage: mix firebird.analyze <file_or_dir> [...]")
    end

    files = resolve_files(paths)

    if Enum.empty?(files) do
      Mix.raise("No .ex or .exs files found in the specified paths")
    end

    Mix.shell().info("🔍 Firebird WASM Analyzer")
    Mix.shell().info("")

    Enum.each(files, fn file ->
      analyze_file(file)
    end)
  end

  defp resolve_files(paths) do
    Enum.flat_map(paths, fn path ->
      cond do
        File.dir?(path) -> Path.wildcard(Path.join(path, "**/*.{ex,exs}"))
        File.regular?(path) -> [path]
        true -> []
      end
    end)
    |> Enum.sort()
    |> Enum.uniq()
  end

  defp analyze_file(path) do
    Mix.shell().info("📄 #{path}")

    case Firebird.Compiler.Analyzer.analyze_file(path) do
      {:ok, analysis} ->
        print_analysis(analysis)

      {:error, reason} ->
        Mix.shell().error("  ❌ Cannot analyze: #{inspect(reason)}")
    end

    Mix.shell().info("")
  end

  defp print_analysis(analysis) do
    status = if analysis.compilable, do: "✅ Compilable", else: "⚠ Partial"
    Mix.shell().info("  Module: #{analysis.module} (#{status})")

    for func <- analysis.functions do
      icon = if func.compilable, do: "✅", else: "❌"

      rec_info =
        cond do
          func.tail_recursive -> " [tail-recursive]"
          func.recursive -> " [recursive]"
          true -> ""
        end

      Mix.shell().info(
        "    #{icon} #{func.name}/#{func.arity} #{func.estimated_complexity}#{rec_info}"
      )

      for issue <- func.issues do
        Mix.shell().info("       ⚠ #{issue}")
      end
    end

    if Enum.any?(analysis.suggestions) do
      Mix.shell().info("")
      Mix.shell().info("  💡 Suggestions:")

      for sug <- analysis.suggestions do
        Mix.shell().info("    • #{sug}")
      end
    end
  end
end