#!/usr/bin/env mix run

# Voice with Agent Example
#
# Demonstrates using a Codex Agent with the voice pipeline.
# TLS note: set CODEX_CA_CERTIFICATE to a PEM bundle to override trust roots for HTTPS.
# If unset, SSL_CERT_FILE is used instead; blank values are ignored.
# Uses a real audio file (test/fixtures/audio/voice_sample.wav) for input.
# Saves received audio to /tmp/codex_voice_agent.pcm
#
# Audio formats:
# - Input:  16-bit PCM, 24kHz, mono (WAV file)
# - Output: 16-bit PCM, 24kHz, mono (saved to /tmp)
#
# To play the output: aplay -f S16_LE -r 24000 -c 1 /tmp/codex_voice_agent.pcm
#
# Usage:
#   mix run examples/voice_with_agent.exs

defmodule VoiceWithAgentExample do
  @moduledoc """
  Example demonstrating voice pipelines with Codex Agents using real audio.
  """

  alias Codex.Agent
  alias Codex.Voice.AgentWorkflow
  alias Codex.Voice.Config
  alias Codex.Voice.Config.TTSSettings
  alias Codex.Voice.Events.VoiceStreamEventAudio
  alias Codex.Voice.Events.VoiceStreamEventLifecycle
  alias Codex.Voice.Events.VoiceStreamEventError
  alias Codex.Voice.Input.AudioInput
  alias Codex.Voice.Pipeline
  alias Codex.Voice.Result

  @output_audio_path "/tmp/codex_voice_agent.pcm"

  def main do
    case run() do
      :ok ->
        :ok

      {:skip, reason} ->
        IO.puts("SKIPPED: #{reason}")

      {:error, reason} ->
        IO.puts("[Error] #{inspect(reason)}")
        System.halt(1)
    end
  end

  def run do
    IO.puts("=== Voice with Agent Example ===\n")

    # Voice auth accepts Codex.Auth precedence and OPENAI_API_KEY.
    unless fetch_api_key() do
      {:error, "no API key found (CODEX_API_KEY, auth.json OPENAI_API_KEY, or OPENAI_API_KEY)"}
    else
      with {:ok, audio_data} <- load_fixture_audio(),
           :ok <- initialize_output_file() do
        # Create an agent with instructions
        {:ok, agent} =
          Agent.new(
            name: "CustomerServiceAgent",
            model: "gpt-4o",
            instructions: """
            You are a customer service agent for an e-commerce company.
            Help customers with their orders. Be friendly and professional.
            Keep responses concise since this is a voice interaction.
            """
          )

        IO.puts("[OK] Created agent: #{agent.name}")
        IO.puts("  Model: #{agent.model}")

        # Create workflow from agent with context
        context = %{
          customer_id: "CUST-12345",
          session_start: DateTime.utc_now()
        }

        workflow = AgentWorkflow.new(agent, context: context)

        IO.puts("\nWorkflow context:")
        IO.puts("  customer_id: #{context.customer_id}")
        IO.puts("  session_start: #{context.session_start}")

        # Create pipeline configuration
        config = %Config{
          workflow_name: "CustomerServiceDemo",
          tts_settings: %TTSSettings{
            voice: :nova,
            speed: 1.0
          }
        }

        # Create pipeline
        pipeline =
          Pipeline.new(
            workflow: workflow,
            config: config
          )

        IO.puts("\n[OK] Pipeline created")
        IO.puts("  STT Model: #{pipeline.stt_model.model}")
        IO.puts("  TTS Model: #{pipeline.tts_model.model}")

        # Create audio input from WAV file
        audio = AudioInput.new(audio_data)

        IO.puts("\nRunning voice pipeline...")

        # Pipeline.run always returns {:ok, result} - errors are delivered as events
        {:ok, result} = Pipeline.run(pipeline, audio)

        process_results(result)
      end
    end
  end

  defp process_results(result) do
    stats =
      result
      |> Result.stream()
      |> Enum.reduce(
        %{
          audio_bytes: 0,
          turns: 0,
          error_count: 0,
          session_ended?: false,
          insufficient_quota?: false
        },
        fn event, acc ->
          handle_event(event, acc)
        end
      )

    if stats.insufficient_quota? do
      {:skip, "insufficient_quota"}
    else
      if stats.error_count > 0 and not stats.session_ended? do
        {:error, :voice_agent_pipeline_failed}
      else
        IO.puts("\n[OK] Pipeline Complete")
        IO.puts("  Total audio output: #{stats.audio_bytes} bytes")
        IO.puts("  Total turns: #{stats.turns}")

        # Show output file info and playback instructions
        output_size = File.stat!(@output_audio_path).size

        IO.puts("""

        Audio saved to: #{@output_audio_path}
        Output file size: #{output_size} bytes

        To play the response audio:
          aplay -f S16_LE -r 24000 -c 1 #{@output_audio_path}

        Or convert to WAV:
          sox -t raw -r 24000 -b 16 -c 1 -e signed-integer #{@output_audio_path} /tmp/response.wav
        """)

        :ok
      end
    end
  end

  defp load_fixture_audio do
    audio_file_path = Path.join([__DIR__, "..", "test", "fixtures", "audio", "voice_sample.wav"])

    case File.read(audio_file_path) do
      {:ok, wav_data} ->
        IO.puts("[OK] Loaded audio file: #{byte_size(wav_data)} bytes")
        {:ok, wav_data}

      {:error, reason} ->
        {:error, {:audio_fixture_read_failed, reason}}
    end
  end

  defp initialize_output_file do
    File.write!(@output_audio_path, "")
    IO.puts("[OK] Output audio will be saved to: #{@output_audio_path}")
    :ok
  end

  defp handle_event(%VoiceStreamEventAudio{data: data}, stats) when is_binary(data) do
    # Append audio to output file
    File.write!(@output_audio_path, data, [:append])
    IO.write(".")
    %{stats | audio_bytes: stats.audio_bytes + byte_size(data)}
  end

  defp handle_event(%VoiceStreamEventAudio{data: nil}, stats) do
    stats
  end

  defp handle_event(%VoiceStreamEventLifecycle{event: :turn_started}, stats) do
    IO.puts("\n[Turn started]")
    stats
  end

  defp handle_event(%VoiceStreamEventLifecycle{event: :turn_ended}, stats) do
    IO.puts("\n[Turn ended]")
    %{stats | turns: stats.turns + 1}
  end

  defp handle_event(%VoiceStreamEventLifecycle{event: :session_ended}, stats) do
    IO.puts("\n[Session ended]")
    %{stats | session_ended?: true}
  end

  defp handle_event(%VoiceStreamEventError{error: error}, stats) do
    IO.puts("\n[Error] #{inspect(error)}")

    %{
      stats
      | error_count: stats.error_count + 1,
        insufficient_quota?: stats.insufficient_quota? or insufficient_quota_error?(error)
    }
  end

  defp handle_event(_event, stats) do
    stats
  end

  defp insufficient_quota_error?(error) do
    error
    |> inspect(limit: :infinity)
    |> String.downcase()
    |> String.contains?("insufficient_quota")
  end

  defp fetch_api_key, do: Codex.Auth.direct_api_key()
end

VoiceWithAgentExample.main()