# Terminal
bin/rails g scaffold projects name transcription:text status:integer
bin/rails active_storage:install
bin/rails g job ProcessTranscription
bundle add sidekiq

asdf plugin add python
asdf install python 3.10.9
brew install ffmpeg
pip install torch openai-whisper

# db/migrate/20230402012647_create_projects.rb
t.integer :status, default: 0

# app/models/project.rb
class Project < ApplicationRecord
  has_one_attached :file

  enum status: {
    pending: 0,
    processing: 1,
    failed: 2,
    completed: 3
  }

  broadcasts
end

# app/views/projects/_form.html.erb
<div class="mb-3">
  <%= form.label :file, class: 'form-label' %>
  <%= form.file_field :file, class: 'form-control' %>
</div>

# app/controllers/projects_controller.rb
def create
  @project = Project.new(project_params)
  if @project.save
    ProcessTranscriptionJob.perform_later(@project.id)
    redirect_to @project, notice: "Project was successfully created."
  else
    render :new, status: :unprocessable_entity
  end
end
def update
  if @project.update(project_params)
    @project.pending!
    ProcessTranscriptionJob.perform_later(@project.id)
    redirect_to @project, notice: "Project was successfully updated."
  else
    render :edit, status: :unprocessable_entity
  end
end

def project_params
  params.require(:project).permit(:name, :transcription, :file)
end

# app/jobs/process_transcription_job.rb
class ProcessTranscriptionJob < ApplicationJob
  queue_as :transcriber

  def perform(project_id)
    return unless project = Project.find_by(id: project_id)
    return unless project.file.attached?
    return unless project.pending? || project.failed?

    project.processing!
    File.binwrite(Rails.root.join("tmp", project_id.to_s), project.file.download)

    transcription = TRANSCRIBER.transcribe_audio(Rails.root.join("tmp", project_id.to_s))
    if transcription && project.update(transcription: transcription)
      project.completed!
    else
      project.failed!
      ProcessTranscriptionJob.set(wait: 10.seconds).perform_later(project_id)
    end
  rescue Transcriber::NotAvailable
    project.failed!
    ProcessTranscriptionJob.set(wait: 10.seconds).perform_later(project_id)
  ensure
    FileUtils.rm_rf(Rails.root.join("tmp", project_id.to_s))
  end
end

# Procfile.dev
web: unset PORT && bin/rails server
worker: sidekiq -C config/sidekiq_default.yml
transcriber: WHISPER=true sidekiq -C config/sidekiq_transcriber.yml
js: yarn build --watch
css: yarn build:css --watch

# config/sidekiq_default.yml
:concurrency: 4
:queues:
  - default

# config/sidekiq_transcriber.yml
:concurrency: 1
:queues:
  - transcriber

# config/application.rb
config.active_job.queue_adapter = :sidekiq

# config/initializers/transcriber.rb
require "open3"

class Transcriber
  class NotAvailable < StandardError; end

  def initialize
    return unless ENV["WHISPER"] == 'true'
    @stdin, @stdout, @stderr, @wait_thr = Open3.popen3("python -u #{Rails.root.join("lib", "main.py")}")
  end

  def transcribe_audio(audio_file)
    raise Transcriber::NotAvailable unless @stdin
    @stdin.puts(audio_file)
    output = ""
    while line = @stdout.gets
      break if line.strip == "___TRANSCRIPTION_END___"
      output += line
    end
    output.strip
  rescue Errno::EPIPE
    @stdin, @stdout, @stderr, @wait_thr = Open3.popen3("python -u #{Rails.root.join("lib", "main.py")}")
    retry
  end
end

TRANSCRIBER = Transcriber.new

# lib/main.py
import sys
import torch
import whisper
import warnings
from torch.multiprocessing import Process, Queue

warnings.filterwarnings("ignore")
device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
model = whisper.load_model("small.en").to(device)

def transcribe_audio(audio_file, output_queue):
  result = model.transcribe(audio_file)
  output_queue.put(result["text"])

def start_model_server(input_queue, output_queue):
  while True:
    audio_file = input_queue.get()
    if audio_file is None:
      break
    transcribe_audio(audio_file, output_queue)

if __name__ == "__main__":
  if torch.multiprocessing.get_start_method(allow_none=True) is None:
    torch.multiprocessing.set_start_method("spawn")

  input_queue = Queue()
  output_queue = Queue()
  model_process = Process(target=start_model_server, args=(input_queue, output_queue))
  model_process.start()

  while True:
    input_file = sys.stdin.readline().strip()
    if not input_file or input_file == "exit":
      input_queue.put(None)
      break
    input_queue.put(input_file)
    print(output_queue.get(), flush=True)
    print("___TRANSCRIPTION_END___", flush=True)

# app/views/projects/_project.html.erb
<%= turbo_stream_from project %>

<div id="<%= dom_id project %>" class="scaffold_record">

  <div class="container my-5">
    <div class="progress" style="height: 40px; border-radius: 20px; overflow: hidden;">
      <div class="progress-bar <%= ["pending", "processing", "completed"].include?(project.status) ? "bg-success" : "bg-secondary" %>" role="progressbar" style="width: 25%">
        <span class="d-flex justify-content-center align-items-center h-100 text-white fw-bold">Pending</span>
      </div>
      <div class="progress-bar <%= ["processing", "completed"].include?(project.status) ? "bg-success" : "bg-secondary" %>" role="progressbar" style="width: 50%">
        <span class="d-flex justify-content-center align-items-center h-100 text-white fw-bold">Processing</span>
      </div>
      <% if project.failed? %>
        <div class="progress-bar bg-danger" role="progressbar" style="width: 25%">
          <span class="d-flex justify-content-center align-items-center h-100 text-white fw-bold">Failed</span>
        </div>
      <% else %>
        <div class="progress-bar <%= ["completed"].include?(project.status) ? "bg-success" : "bg-secondary" %>" role="progressbar" style="width: 25%">
          <span class="d-flex justify-content-center align-items-center h-100 text-white fw-bold">Completed</span>
        </div>
      <% end %>
    </div>
  </div>

  <p>
    <strong>Name:</strong>
    <%= project.name %>
  </p>

  <p>
    <strong>Transcription:</strong>
    <%= project.transcription %>
  </p>

  <p>
    <strong>Status:</strong>
    <%= project.status %>
  </p>

</div>