# Velour Phase 1: MVP (Local Filesystem)

Phase 1 delivers a complete video library application for local files with grouping, transcoding, and playback. This is the foundation that provides immediate value.

**Architecture Note**: This phase implements a extensible MediaFile architecture using Single Table Inheritance (STI). Video inherits from MediaFile, preparing the system for future audio support in Phase 5.

## Technology Stack

### Core Components
- **Ruby on Rails 8.x** with SQLite3
- **Hotwire** (Turbo + Stimulus) for frontend
- **Solid Queue** for background jobs
- **Video.js** for video playback
- **FFmpeg** for video processing
- **Active Storage** for thumbnails/assets
- **TailwindCSS** for styling

## Database Schema (Core Models)

### Work Model
```ruby
class Work < ApplicationRecord
  validates :title, presence: true

  has_many :videos, dependent: :destroy
  has_many :external_ids, dependent: :destroy

  scope :organized, -> { where(organized: true) }
  scope :unorganized, -> { where(organized: false) }

  def primary_video
    videos.order(created_at: :desc).first
  end
end
```

### MediaFile Model (Base Class)
```ruby
class MediaFile < ApplicationRecord
  # Base class for all media files using STI
  include Streamable, Processable

  # Common associations
  belongs_to :work
  belongs_to :storage_location
  has_many :playback_sessions, dependent: :destroy

  # Common metadata stores
  store :fingerprints, accessors: [:xxhash64, :md5, :oshash, :phash]
  store :media_metadata, accessors: [:duration, :codec, :bit_rate, :format]

  # Common validations and methods
  validates :filename, presence: true
  validates :xxhash64, presence: true, uniqueness: { scope: :storage_location_id }

  scope :web_compatible, -> { where(web_compatible: true) }
  scope :needs_transcoding, -> { where(web_compatible: false) }

  def display_title
    work&.display_title || filename
  end

  def full_file_path
    File.join(storage_location.path, filename)
  end

  def format_duration
    # Duration formatting logic
  end
end
```

### Video Model (Inherits from MediaFile)
```ruby
class Video < MediaFile
  # Video-specific associations
  has_many :video_assets, dependent: :destroy

  # Video-specific metadata
  store :video_metadata, accessors: [:width, :height, :video_codec, :audio_codec, :frame_rate]

  # Video-specific methods
  def resolution_label
    # Resolution-based quality labeling (SD, 720p, 1080p, 4K, etc.)
  end
end
```

### StorageLocation Model
```ruby
class StorageLocation < ApplicationRecord
  has_many :videos, dependent: :destroy

  validates :name, presence: true
  validates :path, presence: true, uniqueness: true
  validates :storage_type, presence: true, inclusion: { in: %w[local] }

  validate :path_must_exist_and_be_readable

  def accessible?
    File.exist?(path) && File.readable?(path)
  end

  private

  def path_must_exist_and_be_readable
    errors.add(:path, "must exist and be readable") unless accessible?
  end
end
```

## Storage Architecture (Local Only)

### Directory Structure
```bash
# User's original media directories (read-only references)
/movies/action/Die Hard (1988).mkv
/movies/anime/Your Name (2016).webm
/movies/scifi/The Matrix (1999).avi

# Velour transcoded files (same directories, web-compatible)
/movies/action/Die Hard (1988).web.mp4
/movies/anime/Your Name (2016).web.mp4
/movies/scifi/The Matrix (1999).web.mp4

# Velour managed directories
./velour_data/
├── assets/               # Active Storage for generated content
│   └── thumbnails/      # Video screenshots
└── tmp/                 # Temporary processing files
    └── transcodes/      # Temporary transcode storage
```

### Docker Volume Mounting with Heuristic Discovery

Users mount their video directories under `/videos` and Velour automatically discovers and categorizes them:

```yaml
# docker-compose.yml
volumes:
  - /path/to/user/movies:/videos/movies:ro
  - /path/to/user/tv_shows:/videos/tv:ro
  - /path/to/user/documentaries:/videos/docs:ro
  - /path/to/user/anime:/videos/anime:ro
  - ./velour_data:/app/velour_data
```

### Automatic Storage Location Discovery
```ruby
# app/services/storage_discovery_service.rb
class StorageDiscoveryService
  CATEGORIES = {
    'movies' => 'Movies',
    'tv' => 'TV Shows',
    'tv_shows' => 'TV Shows',
    'series' => 'TV Shows',
    'docs' => 'Documentaries',
    'documentaries' => 'Documentaries',
    'anime' => 'Anime',
    'cartoons' => 'Animation',
    'animation' => 'Animation',
    'sports' => 'Sports',
    'music' => 'Music Videos',
    'music_videos' => 'Music Videos',
    'kids' => 'Kids Content',
    'family' => 'Family Content'
  }.freeze

  def self.discover_and_create
    base_path = '/videos'
    return [] unless Dir.exist?(base_path)

    discovered = []

    Dir.children(base_path).each do |subdir|
      dir_path = File.join(base_path, subdir)
      next unless Dir.exist?(dir_path)

      category = categorize_directory(subdir)
      storage = StorageLocation.find_or_create_by!(
        name: "#{category}: #{subdir.titleize}",
        path: dir_path,
        storage_type: 'local'
      )

      discovered << storage
    end

    discovered
  end

  def self.categorize_directory(dirname)
    downcase = dirname.downcase
    CATEGORIES[downcase] || CATEGORIES.find { |key, _| downcase.include?(key) }&.last || 'Other'
  end
end
```

## Video Processing Pipeline

### Background Job with ActiveJob 8.1 Continuations
```ruby
class VideoProcessorJob < ApplicationJob
  include ActiveJob::Statuses

  def perform(video_id)
    video = Video.find(video_id)

    progress.update(stage: "metadata", total: 100, current: 0)
    metadata = VideoMetadataExtractor.new(video.full_file_path).extract
    video.update!(video_metadata: metadata)
    progress.update(stage: "metadata", total: 100, current: 100)

    progress.update(stage: "thumbnail", total: 100, current: 0)
    generate_thumbnail(video)
    progress.update(stage: "thumbnail", total: 100, current: 100)

    unless video.web_compatible?
      progress.update(stage: "transcode", total: 100, current: 0)
      transcode_video(video)
      progress.update(stage: "transcode", total: 100, current: 100)
    end

    progress.update(stage: "complete", total: 100, current: 100)
  end

  private

  def generate_thumbnail(video)
    # Generate thumbnail at 10% of duration
    thumbnail_path = VideoTranscoder.new.extract_frame(video.full_file_path, video.duration * 0.1)
    video.video_assets.create!(asset_type: "thumbnail", file: File.open(thumbnail_path))
  end

  def transcode_video(video)
    transcoder = VideoTranscoder.new
    output_path = video.full_file_path.gsub(/\.[^.]+$/, '.web.mp4')

    transcoder.transcode_for_web(
      input_path: video.full_file_path,
      output_path: output_path,
      on_progress: ->(current, total) { progress.update(current: current) }
    )

    video.update!(
      transcoded_path: File.basename(output_path),
      transcoded_permanently: true,
      web_compatible: true
    )
  end
end
```

## Frontend Architecture

### Uninterrupted Video Playback
```erb
<!-- videos/show.html.erb -->
<turbo-frame id="video-player-frame" data-turbo-permanent>
  <div class="video-container">
    <video
      id="video-player"
      data-controller="video-player"
      data-video-player-video-id-value="<%= @video.id %>"
      data-video-player-start-position-value="<%= @last_position %>"
      class="w-full"
      controls>
      <source src="<%= stream_video_path(@video) %>" type="video/mp4">
    </video>
  </div>
</turbo-frame>

<turbo-frame id="video-info">
  <h1><%= @work.title %></h1>
  <p>Duration: <%= format_duration(@video.duration) %></p>
</turbo-frame>
```

### Video Player Stimulus Controller
```javascript
// app/javascript/controllers/video_player_controller.js
import { Controller } from "@hotwired/stimulus"

export default class extends Controller {
  static values = { videoId: Number, startPosition: Number }

  connect() {
    this.player = videojs(this.element, {
      controls: true,
      responsive: true,
      fluid: true,
      playbackRates: [0.5, 1, 1.25, 1.5, 2]
    })

    this.player.ready(() => {
      if (this.startPositionValue > 0) {
        this.player.currentTime(this.startPositionValue)
      }
    })

    // Save position every 10 seconds
    this.interval = setInterval(() => {
      this.savePosition()
    }, 10000)

    // Save on pause
    this.player.on("pause", () => this.savePosition())
  }

  disconnect() {
    clearInterval(this.interval)
    this.player.dispose()
  }

  savePosition() {
    const position = Math.floor(this.player.currentTime())

    fetch(`/videos/${this.videoIdValue}/playback-position`, {
      method: "PATCH",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ position })
    })
  }
}
```

## Service Objects

### File Scanner Service
```ruby
class FileScannerService
  def initialize(storage_location)
    @storage_location = storage_location
  end

  def scan
    return failure_result("Storage location not accessible") unless @storage_location.accessible?

    video_files = find_video_files
    new_videos = process_files(video_files)

    success_result(new_videos)
  rescue => e
    failure_result(e.message)
  end

  private

  def find_video_files
    Dir.glob(File.join(@storage_location.path, "**", "*.{mp4,avi,mkv,mov,wmv,flv,webm,m4v}"))
  end

  def process_files(file_paths)
    new_videos = []

    file_paths.each do |file_path|
      filename = File.basename(file_path)

      next if Video.exists?(filename: filename, storage_location: @storage_location)

      video = Video.create!(
        filename: filename,
        storage_location: @storage_location,
        work: Work.find_or_create_by(title: extract_title(filename))
      )

      new_videos << video
      VideoProcessorJob.perform_later(video.id)
    end

    new_videos
  end

  def extract_title(filename)
    # Simple title extraction - can be enhanced
    File.basename(filename, ".*").gsub(/[\[\(].*?[\]\)]/, "").strip
  end

  def success_result(videos = [])
    { success: true, videos: videos, message: "Found #{videos.length} new videos" }
  end

  def failure_result(message)
    { success: false, message: message }
  end
end
```

### Video Transcoder Service
```ruby
class VideoTranscoder
  def transcode_for_web(input_path:, output_path:, on_progress: nil)
    movie = FFMPEG::Movie.new(input_path)

    # Calculate progress callback
    progress_callback = ->(progress) {
      on_progress&.call(progress, 100)
    }

    movie.transcode(output_path, {
      video_codec: "libx264",
      audio_codec: "aac",
      custom: %w[
        -pix_fmt yuv420p
        -preset medium
        -crf 23
        -movflags +faststart
        -tune fastdecode
      ]
    }, &progress_callback)
  end

  def extract_frame(input_path, seconds)
    movie = FFMPEG::Movie.new(input_path)
    output_path = "#{Rails.root}/tmp/thumbnail_#{SecureRandom.hex(8)}.jpg"

    movie.screenshot(output_path, seek_time: seconds, resolution: "320x240")
    output_path
  end
end
```

## Routes

```ruby
Rails.application.routes.draw do
  root "storage_locations#index"

  resources :storage_locations, only: [:index, :show, :create, :destroy] do
    member do
      post :scan
    end
  end

  resources :works, only: [:index, :show] do
    resources :videos, only: [:show]
  end

  resources :videos, only: [] do
    member do
      get :stream
      patch :playback_position
      post :retry_processing
    end

    resources :playback_sessions, only: [:create]
  end

  # Real-time job progress
  resources :jobs, only: [:show] do
    member do
      get :progress
    end
  end
end
```

## Implementation Sub-Phases

### Phase 1A: Core Foundation (Week 1-2)
1. Generate models with migrations
2. Implement model validations and associations
3. Create storage adapter pattern
4. Create FileScannerService
5. Basic UI for storage locations and video listing

### Phase 1B: Video Playback (Week 3)
1. Video streaming controller with byte-range support
2. Video.js integration with Stimulus controller
3. Playback session tracking
4. Resume functionality

### Phase 1C: Processing Pipeline (Week 4)
1. Video metadata extraction with FFmpeg
2. Background job processing with progress tracking
3. Thumbnail generation and storage
4. Processing UI with status indicators

### Phase 1D: Works & Grouping (Week 5)
1. Duplicate detection by file hash
2. Manual grouping interface
3. Works display with version selection
4. Search, filtering, and pagination

## Configuration

### Environment Variables
```bash
# Required
RAILS_ENV=development
RAILS_MASTER_KEY=your_master_key

# Video processing
FFMPEG_PATH=/usr/bin/ffmpeg
FFPROBE_PATH=/usr/bin/ffprobe

# Storage
VIDEOS_PATH=./velour_data/videos
MAX_TRANSCODE_SIZE_GB=50

# Background jobs (SolidQueue runs with defaults)
SOLID_QUEUE_PROCESSES="*:2"  # 2 workers for all queues
```

### Docker Configuration
```dockerfile
FROM ruby:3.3-alpine

# Install FFmpeg and other dependencies
RUN apk add --no-cache \
    ffmpeg \
    imagemagick \
    sqlite-dev \
    nodejs \
    npm

# Install Rails and other gems
COPY Gemfile* /app/
RUN bundle install

# Copy application code
COPY . /app/

# Create directories
RUN mkdir -p /app/velour_data/{assets,tmp}

EXPOSE 3000
CMD ["rails", "server", "-b", "0.0.0.0"]
```

## Testing Strategy

### Model Tests
- Model validations and associations
- Scopes and class methods
- JSON store accessor functionality

### Service Tests
- FileScannerService with sample directory
- VideoTranscoder service methods
- Background job processing

### System Tests
- Video playback functionality
- File scanning workflow
- Work grouping interface

This Phase 1 delivers a complete, useful video library application that provides immediate value while establishing the foundation for future enhancements.