# Architecture

A contributor-facing map of how SubMiner is put together. The canonical internal guidance, including domain ownership and layering rules, is [`docs/architecture/README.md`](https://github.com/ksyasuda/SubMiner/blob/main/docs/architecture/README.md) in the repo.

SubMiner runs as three cooperating runtimes:

- the Electron desktop app (`src/`): overlay, UI, and runtime orchestration
- the launcher CLI (`launcher/`): mpv and app command workflows
- the mpv Lua plugin (`plugin/subminer/`): player-side controls and handoff to the app

Inside the app, `src/main.ts` is a composition root. It owns wiring and state, and delegates behavior to small runtime and domain modules that can be tested without Electron or mpv.

## Project layout

```text
launcher/
  main.ts                 # entrypoint and command dispatch
  commands/               # one module per subcommand (playback, jellyfin, stats, sync, ...)
  config/                 # launcher config readers and CLI parser
plugin/subminer/          # mpv plugin; main.lua loads init.lua, which boots the other modules
src/
  main-entry.ts           # bootstrap wrapper that runs before main.js
  main.ts                 # composition root
  preload*.ts             # preload bridges (overlay, settings, stats, sync, Jellyfin setup)
  main/                   # main-process runtime modules and IPC/CLI wiring
    boot/                 # pre-ready boot helpers
    runtime/composers/    # larger runtime clusters assembled for main.ts
    runtime/domains/      # domain barrels (startup, overlay, mpv, ipc, shortcuts, anilist, jellyfin, mining)
  core/services/          # focused services: mpv client, overlay, tokenizer, mining, integrations, stats
  core/utils/             # pure helpers
  shared/ipc/             # IPC channel constants and payload validators
  renderer/               # overlay renderer: subtitle rendering, input handlers, modals
  config/                 # definitions/ (defaults + option registries) and resolve/ (resolution pipeline)
  cli/                    # app CLI parsing and help output
  settings/, syncui/      # settings and sync windows
  window-trackers/        # Hyprland, Sway, X11, macOS, and Windows trackers
  anki-integration/       # AnkiConnect proxy and note-update workflow
  jimaku/, subsync/, tsukihime/  # integration helpers
  types/                  # shared domain types
stats/                    # stats dashboard UI (Vite)
vendor/                   # Yomitan fork, texthooker-ui, JLPT vocab
```

A few ownership notes that are hard to guess from file names:

- mpv access is split into transport (`mpv-transport.ts`), protocol (`mpv-protocol.ts`), and property modules under `src/core/services/`.
- The renderer keeps `renderer.ts` to orchestration. Keyboard, mouse, and gamepad input live in `renderer/handlers/`, and each modal flow has its own file in `renderer/modals/`.
- AniSkip intro detection runs in the app (`src/main/runtime/aniskip-runtime.ts`), which drives mpv chapters and the skip key over the mpv IPC socket. The plugin does not handle it.

## Component diagram

The main process drives one primary overlay window plus modal surfaces. Primary and secondary subtitle layers render in the same overlay renderer, connected to the main process through `preload.ts`. The launcher and mpv plugin run as separate processes and talk to the app through sockets or CLI passthrough.

```mermaid
flowchart TB
  classDef entry fill:#c6a0f6,stroke:#494d64,color:#24273a,stroke-width:2px,font-weight:bold
  classDef comp fill:#b7bdf8,stroke:#494d64,color:#24273a,stroke-width:1.5px
  classDef svc fill:#8aadf4,stroke:#494d64,color:#24273a,stroke-width:1.5px
  classDef bridge fill:#f5a97f,stroke:#494d64,color:#24273a,stroke-width:1.5px
  classDef rend fill:#8bd5ca,stroke:#494d64,color:#24273a,stroke-width:1.5px
  classDef ext fill:#a6da95,stroke:#494d64,color:#24273a,stroke-width:1.5px
  classDef extrt fill:#eed49f,stroke:#494d64,color:#24273a,stroke-width:1.5px

  subgraph ExtRt["External Runtimes"]
    direction LR
    Launcher["Launcher CLI"]:::extrt
    Plugin["mpv Plugin"]:::extrt
  end

  Main["main.ts"]:::entry

  subgraph Comp["Composition"]
    direction LR
    Startup["Startup & Lifecycle"]:::comp
    Wiring["Runtime Wiring"]:::comp
    Composers["Domain Composers"]:::comp
  end

  subgraph Svc["Services"]
    direction LR
    Mpv["MPV Stack"]:::svc
    OverlaySvc["Overlay Manager"]:::svc
    Mining["Mining & Subtitles"]:::svc
    AnkiProxy["Anki Proxy"]:::svc
    Integrations["Integrations"]:::svc
    Tracking["Tracking"]:::svc
    Config["Config & Options"]:::svc
  end

  Bridge(["preload.ts"]):::bridge

  subgraph Rend["Renderer"]
    direction LR
    OverlayWin["Overlay Window"]:::rend
    UI["Subtitles & Modals"]:::rend
  end

  subgraph Ext["External Systems"]
    direction LR
    mpvExt["mpv"]:::ext
    AnkiExt["AnkiConnect"]:::ext
    JimakuExt["Jimaku"]:::ext
    TrackerExt["Window Tracker"]:::ext
    AnilistExt["AniList"]:::ext
    JellyfinExt["Jellyfin"]:::ext
    DiscordExt["Discord"]:::ext
  end

  Launcher -->|"CLI"| Main
  Plugin -->|"IPC"| mpvExt

  Main --> Comp
  Comp --> Svc

  Svc --> Bridge
  Bridge --> Rend

  mpvExt <-->|"socket"| Mpv
  AnkiExt <-->|"HTTP"| AnkiProxy
  JimakuExt <-->|"HTTP"| Integrations
  TrackerExt <-->|"platform"| OverlaySvc
  AnilistExt <-->|"HTTP"| Tracking
  JellyfinExt <-->|"HTTP"| Tracking
  DiscordExt <-->|"RPC"| Integrations

  style Comp fill:#363a4f,stroke:#494d64,color:#cad3f5
  style Svc fill:#363a4f,stroke:#494d64,color:#cad3f5
  style Rend fill:#363a4f,stroke:#494d64,color:#cad3f5
  style Ext fill:#363a4f,stroke:#494d64,color:#cad3f5
  style ExtRt fill:#363a4f,stroke:#494d64,color:#cad3f5
```

## Composition pattern

Runtime code uses dependency injection:

1. Put the logic in a service under `src/core/services/`, as pure or side-effect-bounded functions.
2. Build its runtime dependencies in a `src/main/` module. Pass simple dependencies inline; extract an adapter only when it adds behavior or gets reused.
3. Call the service from lifecycle or command wiring.

`main.ts` gets domain handlers through `createMainRuntimeRegistry()` (`src/main/runtime/registry.ts`), which exposes the barrels in `src/main/runtime/domains/`. Larger clusters, such as app-ready startup, mpv, Jellyfin, AniList tracking, shortcuts, and IPC, are assembled by composers in `src/main/runtime/composers/`. Many handlers take a `*MainDeps` object built by a `createBuild*MainDepsHandler` builder, which keeps side effects out of the unit under test.

Composers declare their inputs with `ComposerInputs<T>` and results with `ComposerOutputs<T>` from `src/main/runtime/composers/contracts.ts`. A missing dependency then fails at compile time.

### IPC boundary

Channel names live in `src/shared/ipc/contracts.ts` and payload validators in `src/shared/ipc/validators.ts`. Renderer payloads are validated at the IPC entry points (`src/core/services/ipc.ts`, `src/core/services/anki-jimaku-ipc.ts`) before any domain handler runs. See [IPC + runtime contracts](/ipc-contracts) for the full rules.

### Runtime state ownership

Some domains, such as AniList token, queue, and media-guess state, use reducer-style transitions:

- Composition modules own the mutable state and expose narrow `get*`/`set*` accessors.
- Handlers change another domain's state only through its transition helpers in `src/main/state.ts`, never by mutating the object directly.
- A transition may update derived counters or snapshots, but must leave metadata it does not own untouched.
- Tests for these domains check both the fields that should change and the ones that should not.

## Playback startup flow

A SubMiner-managed launch (the `subminer` launcher, the app's own playback, or the packaged Windows shortcut) starts mpv, injects the plugin, and brings up the overlay. The launcher reads `config.jsonc`, spawns mpv with the IPC socket and the bundled plugin, and passes runtime settings as `--script-opts`. The plugin never reads a config file: the shipped `subminer.conf` has no settings, so command-line options always win.

Once mpv is up, exactly one of two triggers starts the overlay:

- On a first launch, the launcher sets `auto_start=yes` and the plugin's `file-loaded` hook starts the app once the socket is ready.
- When the app is already running, or for `--start-overlay` and YouTube flows, the launcher attaches over the app control socket and suppresses the plugin's auto-start.

Both paths end in the same app bring-up, which then runs the program lifecycle below.

```mermaid
flowchart TB
  classDef entry fill:#c6a0f6,stroke:#494d64,color:#24273a,stroke-width:2px,font-weight:bold
  classDef extrt fill:#eed49f,stroke:#494d64,color:#24273a,stroke-width:1.5px
  classDef decision fill:#f5a97f,stroke:#494d64,color:#24273a,stroke-width:1.5px
  classDef proc fill:#8aadf4,stroke:#494d64,color:#24273a,stroke-width:1.5px
  classDef app fill:#b7bdf8,stroke:#494d64,color:#24273a,stroke-width:1.5px
  classDef overlay fill:#8bd5ca,stroke:#494d64,color:#24273a,stroke-width:1.5px

  Entry["Managed launch<br/>subminer CLI · app · Windows shortcut"]:::entry
  Entry --> Cfg["Launcher reads config.jsonc<br/>→ plugin runtime config"]:::extrt
  Cfg --> Spawn["Spawn mpv<br/>--input-ipc-server=/tmp/subminer-socket<br/>--script=plugin/subminer/main.lua<br/>--script-opts=subminer-… (auto_start, backend, …)"]:::proc
  Spawn --> Boot["Plugin boot · read_options('subminer')<br/>empty subminer.conf; CLI opts win"]:::extrt
  Boot --> Sock["mpv IPC socket ready"]:::proc
  Sock --> Who{"Overlay trigger"}:::decision

  Who -->|"app already running, or<br/>--start-overlay / YouTube"| Attach["Launcher startOverlay()<br/>attach via control socket<br/>plugin auto-start suppressed"]:::proc
  Who -->|"first launch, auto_start=yes"| Self["Plugin file-loaded hook<br/>polls socket → process.start_overlay()"]:::extrt

  Attach --> AppUp
  Self --> AppUp

  AppUp["Spawn / attach SubMiner app<br/>--start --managed-playback --socket … --backend …"]:::app
  AppUp --> Ctrl["App control server up<br/>/tmp/subminer-control-* dedupes a 2nd launch"]:::app
  Ctrl --> Life["app.whenReady → Program Lifecycle (below)"]:::app
  Life --> Conn["MpvIpcClient connects to /tmp/subminer-socket"]:::overlay
  Conn --> Show["Transparent overlay over mpv<br/>Yomitan lookup · mine"]:::overlay
```

The sockets in this flow are described in [IPC + runtime contracts](./ipc-contracts#runtime-sockets).

## Program lifecycle

1. **Module init.** Before `app.ready`, the composition root registers protocols, sets platform flags, constructs services, and wires dependencies. `runAndApplyStartupState()` parses CLI args and detects the compositor backend.
2. **Startup.** `--generate-config` writes the template and exits. Otherwise `app-lifecycle.ts` takes the single-instance lock and registers Electron lifecycle hooks.
3. **App ready.** `composeAppReadyRuntime()` reloads config strictly, resolves keybindings, creates the `MpvIpcClient` (which connects and observes subtitle and playback properties), and starts the runtime options manager, subtitle timing tracker, and immersion tracker.
4. **Overlay.** `initializeOverlayRuntime()` creates the overlay window, registers global shortcuts, and tracks mpv's window bounds through the active window tracker. `src/main/runtime/overlay-mpv-sub-visibility.ts` hides mpv's own subtitles while the overlay shows them.
5. **Background warmups.** MeCab, Yomitan, JLPT and frequency dictionaries, the optional Jellyfin remote session, Discord presence, AniList token refresh, and the optional AnkiConnect proxy start asynchronously. `startupWarmups` controls which run; its low-power mode defers everything except Yomitan.
6. **Runtime.** Event-driven. mpv property changes, IPC messages, CLI commands, shortcuts, and config hot-reloads route through handlers and composers. Subtitle text goes through `SubtitleProcessingController` (normalize, tokenize, merge) and out to the overlay renderer and modals.
7. **Shutdown.** `onWillQuitCleanup` tears down the tray, config watcher, shortcuts, WebSocket and texthooker servers, mpv socket, window tracker, and Yomitan parser window. It flushes the immersion tracker to SQLite and stops Jellyfin, Discord, and the AnkiConnect proxy.

```mermaid
flowchart TB
  classDef start fill:#c6a0f6,stroke:#494d64,color:#24273a,stroke-width:2px,font-weight:bold
  classDef phase fill:#b7bdf8,stroke:#494d64,color:#24273a,stroke-width:1.5px
  classDef decision fill:#f5a97f,stroke:#494d64,color:#24273a,stroke-width:1.5px
  classDef init fill:#8aadf4,stroke:#494d64,color:#24273a,stroke-width:1.5px
  classDef runtime fill:#8bd5ca,stroke:#494d64,color:#24273a,stroke-width:1.5px
  classDef shutdown fill:#ed8796,stroke:#494d64,color:#24273a,stroke-width:1.5px
  classDef warmup fill:#eed49f,stroke:#494d64,color:#24273a,stroke-width:1.5px

  CLI["CLI + Environment"]:::start
  CLI --> Init["Module Init"]:::phase
  Init --> Parse["Parse argv"]:::phase
  Parse --> GenCheck{"--generate-config?"}:::decision
  GenCheck -->|"yes"| GenExit["Write & exit"]:::phase
  GenCheck -->|"no"| Lock["Acquire lock"]:::phase

  Lock -->|"app.whenReady()"| Ready["App Ready"]:::phase

  Ready --> Config["Config + keybindings"]:::init
  Ready --> MpvInit["MPV socket connect"]:::init
  Ready --> Platform["Runtime services"]:::init

  Config & MpvInit & Platform --> OverlayInit["Overlay Init"]:::phase

  OverlayInit --> MainWin["Create window"]:::init
  OverlayInit --> Shortcuts["Register shortcuts"]:::init

  MainWin & Shortcuts --> Warmups

  subgraph Warmups["Background Warmups (parallel)"]
    direction LR
    W1["MeCab"]:::warmup ~~~ W2["Yomitan"]:::warmup ~~~ W3["Dictionaries"]:::warmup ~~~ W4["Jellyfin"]:::warmup ~~~ W5["Discord"]:::warmup ~~~ W6["AniList"]:::warmup ~~~ W7["Anki Proxy"]:::warmup
  end

  Warmups --> Loop

  subgraph Loop["Event Loop"]
    direction TB
    Events["mpv · IPC · shortcuts · config"]:::runtime
    Events --> Route["Composers"]:::runtime
    Route --> Pipeline["Subtitle Pipeline"]:::runtime
    Pipeline --> Broadcast["State + Renderer"]:::runtime
  end

  style Warmups fill:#363a4f,stroke:#494d64,color:#cad3f5

  Loop -->|"quit"| Quit["Shutdown"]:::shutdown

  subgraph Cleanup[" "]
    direction LR
    T1["UI cleanup"]:::shutdown
    T2["Socket + server teardown"]:::shutdown
    T3["Flush tracking + state"]:::shutdown
  end

  Quit --> Cleanup

  style Cleanup fill:transparent,stroke:none
  style Loop fill:#363a4f,stroke:#494d64,color:#cad3f5
```

## Subtitle prefetch

SubMiner tokenizes upcoming subtitle lines before they appear, so they render from a warm cache. `SubtitlePrefetchService` (`src/core/services/subtitle-prefetch.ts`) gets the cue list from the active track: an external subtitle file, or for local media an embedded text track extracted with ffmpeg. It parses the cues with `subtitle-cue-parser.ts`, picks a window of upcoming lines from the playback position, and tokenizes them through the live pipeline, storing results in the `SubtitleProcessingController` cache.

Live subtitle processing always takes priority; the prefetcher pauses while the on-screen line is being processed. It recomputes its window on seek and re-prefetches when the cache is invalidated, for example after a word is marked known.

```mermaid
flowchart TB
  classDef phase fill:#b7bdf8,stroke:#494d64,color:#24273a,stroke-width:1.5px
  classDef init fill:#8aadf4,stroke:#494d64,color:#24273a,stroke-width:1.5px
  classDef runtime fill:#8bd5ca,stroke:#494d64,color:#24273a,stroke-width:1.5px
  classDef warmup fill:#eed49f,stroke:#494d64,color:#24273a,stroke-width:1.5px

  SubFile["Subtitle Track"]:::init
  Parse["Cue Parser"]:::phase
  Window["Upcoming Lines"]:::phase
  Tokenize["Pre-tokenize"]:::warmup
  Cache["Token Cache"]:::runtime
  Appear["Subtitle Appears"]:::init
  Hit["Cache Hit"]:::runtime
  Render["Fast Render"]:::runtime

  SubFile --> Parse --> Window --> Tokenize --> Cache
  Appear --> Hit --> Render
  Cache -.->|"warm"| Hit

  style SubFile stroke-width:2px
  style Render stroke-width:2px
```

## Extension rules

- Add behavior to a service in `src/core/services/` or a focused module under `src/main/runtime/`. Keep new logic out of `main.ts`.
- For changes that span startup, overlay, mpv, or integration wiring, compose through `src/main/runtime/domains/` and `src/main/runtime/composers/` instead of wiring directly in `main.ts`.
- Add a cross-process channel in `src/shared/ipc/contracts.ts` first, validate it in `src/shared/ipc/validators.ts`, then wire the handler. See [IPC + runtime contracts](/ipc-contracts#add-a-new-ipc-action).
- Config is split by domain under `src/config/definitions/` and `src/config/resolve/`. Keep config changes in the matching domain file.
- Keep CLI flags and IPC channels stable unless a change is meant to break them.
- Add or update focused tests when a runtime boundary or contract changes, including malformed-payload tests for IPC.