defmodule Mix.Tasks.Firebird.Build do
  @moduledoc """
  Build all WASM fixtures from source.

  Compiles Rust, Go (TinyGo), and WAT source files into WASM modules.

  ## Usage

      mix firebird.build          # Build all fixtures
      mix firebird.build --rust   # Build only Rust fixtures
      mix firebird.build --go     # Build only Go fixtures
      mix firebird.build --wat    # Build only WAT fixtures

  ## Prerequisites

  - **Rust**: `rustup target add wasm32-unknown-unknown`
  - **Go**: TinyGo (`tinygo build`)
  - **WAT**: `wat2wasm` from WABT toolkit
  """

  use Mix.Task

  @shortdoc "Build WASM fixtures from source (Rust, Go, WAT)"

  @rust_targets [
    {"fixtures/rust_math", "math", "fixtures/rust_math.wasm", "wasm32-unknown-unknown"},
    {"fixtures/rust_algorithms", "algorithms", "fixtures/rust_algorithms.wasm",
     "wasm32-unknown-unknown"},
    {"fixtures/rust_float", "float_math", "fixtures/rust_float.wasm", "wasm32-unknown-unknown"},
    {"fixtures/rust_wasi", "wasi_demo", "fixtures/rust_wasi.wasm", "wasm32-wasip1"}
  ]

  @go_targets [
    {"fixtures/go_math", "fixtures/go_math.wasm"},
    {"fixtures/go_algorithms", "fixtures/go_algorithms.wasm"},
    {"fixtures/go_bitwise", "fixtures/go_bitwise.wasm"}
  ]

  @wat_targets [
    {"fixtures/wat_examples/math.wat", "fixtures/math.wasm"},
    {"fixtures/wat_examples/bitwise.wat", "fixtures/wat_bitwise.wasm"}
  ]

  @impl Mix.Task
  def run(args) do
    build_all = args == [] or "--all" in args
    build_rust = build_all or "--rust" in args
    build_go = build_all or "--go" in args
    build_wat = build_all or "--wat" in args

    Mix.shell().info("🔥 Firebird WASM Builder\n")

    results = []

    results = if build_rust, do: results ++ build_rust_targets(), else: results
    results = if build_go, do: results ++ build_go_targets(), else: results
    results = if build_wat, do: results ++ build_wat_targets(), else: results

    successes = Enum.count(results, fn {status, _} -> status == :ok end)
    failures = Enum.count(results, fn {status, _} -> status == :error end)
    skipped = Enum.count(results, fn {status, _} -> status == :skip end)

    Mix.shell().info("\n📊 Results: #{successes} built, #{failures} failed, #{skipped} skipped")
  end

  defp build_rust_targets do
    Mix.shell().info("🦀 Building Rust targets...")

    if System.find_executable("cargo") do
      Enum.map(@rust_targets, fn {dir, crate_name, output, target} ->
        if File.dir?(dir) do
          Mix.shell().info("   Building #{dir} (#{target})...")

          case System.cmd("cargo", ["build", "--target", target, "--release"],
                 cd: dir,
                 stderr_to_stdout: true
               ) do
            {_, 0} ->
              src = Path.join([dir, "target/#{target}/release/#{crate_name}.wasm"])
              File.cp!(src, output)
              size = File.stat!(output).size
              Mix.shell().info("   ✅ #{output} (#{size} bytes)")
              {:ok, output}

            {err, _} ->
              Mix.shell().error("   ❌ Failed to build #{dir}: #{err}")
              {:error, dir}
          end
        else
          {:skip, dir}
        end
      end)
    else
      Mix.shell().info("   ⚠️  cargo not found, skipping Rust targets")
      Enum.map(@rust_targets, fn {dir, _, _, _} -> {:skip, dir} end)
    end
  end

  defp build_go_targets do
    Mix.shell().info("🐹 Building Go targets...")

    if System.find_executable("tinygo") do
      Enum.map(@go_targets, fn {dir, output} ->
        if File.dir?(dir) do
          Mix.shell().info("   Building #{dir}...")
          abs_output = Path.absname(output)

          case System.cmd(
                 "tinygo",
                 ["build", "-o", abs_output, "-target", "wasi", "-no-debug", "main.go"],
                 cd: dir,
                 stderr_to_stdout: true
               ) do
            {_, 0} ->
              size = File.stat!(output).size
              Mix.shell().info("   ✅ #{output} (#{size} bytes)")
              {:ok, output}

            {err, _} ->
              Mix.shell().error("   ❌ Failed to build #{dir}: #{err}")
              {:error, dir}
          end
        else
          {:skip, dir}
        end
      end)
    else
      Mix.shell().info("   ⚠️  tinygo not found, skipping Go targets")
      Enum.map(@go_targets, fn {dir, _} -> {:skip, dir} end)
    end
  end

  defp build_wat_targets do
    Mix.shell().info("📝 Building WAT targets...")

    if System.find_executable("wat2wasm") do
      Enum.map(@wat_targets, fn {source, output} ->
        if File.exists?(source) do
          Mix.shell().info("   Building #{source}...")

          case System.cmd("wat2wasm", [source, "-o", output], stderr_to_stdout: true) do
            {_, 0} ->
              size = File.stat!(output).size
              Mix.shell().info("   ✅ #{output} (#{size} bytes)")
              {:ok, output}

            {err, _} ->
              Mix.shell().error("   ❌ Failed: #{err}")
              {:error, source}
          end
        else
          {:skip, source}
        end
      end)
    else
      Mix.shell().info("   ⚠️  wat2wasm not found, skipping WAT targets")
      Enum.map(@wat_targets, fn {source, _} -> {:skip, source} end)
    end
  end
end