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Overview

An Anime Game Launcher provides comprehensive game management features including installation, updates, predownloading, version tracking, and repair functionality. The launcher automatically detects your game state and guides you through necessary actions.

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Launcher States

The launcher uses a state-based system to determine what actions are available. Each state corresponds to a specific condition of your game installation.
The game is fully installed and up-to-date. You can launch the game immediately.Button: “Launch” (green, play icon)
The game is not installed. The launcher will download and install the complete game files.Button: “Download” (download icon)File Location: Downloads to the path configured in config.game.path.for_edition(config.launcher.edition)
A game update is available. The launcher will download and apply the update.Button: “Update” or “Resume” (if partial download exists)Resume Support: If a file matching the update already exists in the temp folder, the button will show “Resume” instead of “Update”
Your installed game version is too old and cannot be updated incrementally.Button: Disabled with warning stylingTooltip: Displays version outdated messageAction Required: Manual game reinstallation
A pre-download for the next game update is available. You can download it in advance.Button: Separate predownload button (save icon)Tooltip: Shows version and download size for predownloadImplementation: Files are downloaded to temp/updating-{matching_field}/.predownloadcomplete

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Game Installation

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Initial Installation

1

Configure Game Path

Set your desired game installation path in the launcher preferences before downloading.The path is stored at config.game.path.for_edition(config.launcher.edition)
2

Start Download

When in GameNotInstalled state, click the “Download” button.The launcher will:
  • Download game files using the configured thread count (config.launcher.sophon.threads)
  • Show progress with downloading status and progress bar
  • Automatically unpack and install files to the game directory
3

Wait for Completion

The download uses multi-threaded downloading for optimal speed.Progress Updates: Real-time progress tracking via ProgressBarMsg::UpdateFromState(state)Error Handling: Download and unpacking errors are displayed with detailed error messages
4

Automatic State Update

After successful installation, the launcher automatically updates its state and checks for next required actions (Wine prefix, DXVK, etc.)

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Game Updates

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Standard Updates

When a game update is available:
  1. The launcher detects the version difference via GAME.try_get_diff()
  2. The state changes to GameUpdateAvailable(diff) with the version diff information
  3. Clicking “Update” triggers download_diff::download_diff() which:
    • Downloads the update files to the temp folder if specified
    • Applies the diff using diff.install_to(game_path, threads, callback)
    • Updates launcher state upon completion
If the download is interrupted, the launcher will show “Resume” instead of “Update” if partial files exist in the temp folder.

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Predownload System

The predownload feature allows downloading updates before they’re officially released. How it works:
  • A separate predownload button appears when PredownloadAvailable state is active
  • Shows the future version and total download size (game + all voice packs)
  • Downloads to temporary folder: temp/updating-{matching_field}/
  • Creates .predownloadcomplete marker file when finished
  • Button changes to success styling (green) when predownload is complete
Code Implementation: 
let mut diffs: Vec<VersionDiff> = vec![game];
diffs.append(&mut voices);

for mut diff in diffs {
    diff = diff.with_temp_folder(tmp.clone());
    diff.download_to(&tmp, progress_callback);
}
Predownloaded files are automatically used when the update officially releases, saving time on update day.

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Version Management

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Version Detection

The launcher performs version checking during initialization: 
sender.input(AppMsg::SetGameDiff(match GAME.try_get_diff() {
    Ok(diff) => Some(diff),
    Err(err) => {
        // Error handling
        None
    }
}));

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Voice Pack Management

Voice packs are treated as separate installable components:
  • VoiceNotInstalled(diff) - Voice pack not installed for selected language
  • VoiceUpdateAvailable(diff) - Voice pack update available
  • VoiceOutdated(diff) - Voice pack version too old
Multi-voice Support: When predownloading, all installed voice packs are included in the download size calculation: 
let mut size = game.downloaded_size().unwrap_or(0);
for voice in voices {
    size += voice.downloaded_size().unwrap_or(0);
}

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Game Repair

The repair function is accessible via the application menu. Access: Menu → Repair Game Implementation: Located in src/ui/main/repair_game.rs What it does:
  • Verifies game file integrity
  • Redownloads corrupted files
  • Fixes installation issues
Repair operations may take significant time depending on the number of corrupted files detected.

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File Locations

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Game Files

  • Installation Path: config.game.path.for_edition(config.launcher.edition)
  • Data Folder: {game_path}/{edition.data_folder()}
  • Web Caches: {data_folder}/webCaches/ (used for wish URL extraction)

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Download Cache

  • Temp Folder: config.launcher.temp or std::env::temp_dir()
  • Update Files: {temp}/updating-{matching_field}/
  • Predownload Marker: {temp}/updating-{matching_field}/.predownloadcomplete

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Download Settings

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Thread Configuration

Downloads use multi-threading for improved performance: Setting: config.launcher.sophon.threads Usage: diff.install_to(game_path, config.launcher.sophon.threads as usize, callback)

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Temp Folder Configuration

Configure a custom temporary folder for downloads: 
if let Some(temp) = config.launcher.temp {
    diff = diff.with_temp_folder(temp);
}
Using a dedicated temp folder on a fast drive (SSD) can significantly improve download and installation speeds.

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Error Handling

The launcher provides detailed error messages for common issues:

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Download Errors

DiffUpdate::InstallerUpdate(InstallerUpdate::DownloadingError(err)) => {
    sender.input(AppMsg::Toast {
        title: tr!("downloading-failed"),
        description: Some(err.to_string())
    });
}

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Unpacking Errors

DiffUpdate::InstallerUpdate(InstallerUpdate::UnpackingError(err)) => {
    sender.input(AppMsg::Toast {
        title: tr!("unpacking-failed"),
        description: Some(err.clone())
    });
}

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Kill Game Process

If the game becomes unresponsive, you can force-close it: Button: “Kill Game Process” (red, appears when game is running) Implementation: 
std::process::Command::new("pkill")
    .arg("-f") // full text search
    .arg("-i") // case-insensitive
    .arg("GenshinImpact|YuanShen|fpsunlock\\.exe")
    .spawn();
The kill button has a 3-second cooldown after each use to prevent accidental spam.

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State Update Flow

The launcher automatically updates its state after major operations:
1

Trigger State Update

AppMsg::UpdateLauncherState is sent after downloads, installations, or configuration changes
2

Check Game Status

LauncherState::get_from_config(updater) analyzes current installation
3

Update UI

The launcher button text, icon, and styling update based on the new state
4

Auto-perform Actions

If perform_on_download_needed is true and a download state is detected, the download starts automatically (used for chained voice pack installations)

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