# file_management.rs — Persistent File Storage
Handles all file I/O for the application. Files are stored inside Tauri's `app_data_dir`, which is platform-specific (e.g. `%APPDATA%\base_station` on Windows). Three subdirectories are used:
**Directory**
**Purpose**
`tasks/`
Saved task plan files
`images/`
Snapshots captured from video feeds
`maps/`
Imported map files
These directories are created automatically on startup by `ensure_storage_dirs_internal()`.
### Commands
**`save_task_file(file_name, data, directory)`** Writes raw bytes to a file in the given subdirectory. Used to persist task plans.
**`list_task_files(directory) → Vec`** Returns a list of filenames in the given subdirectory. Returns an empty list if the directory doesn't exist yet.
**`read_task_file(file_name) → Vec`** Reads a file from the `tasks/` directory and returns its raw bytes.
**`delete_one_file(directory, file_name)`** Deletes a single named file from the given subdirectory. Does nothing if the file doesn't exist.
**`delete_all_task_files(directory)`** Removes all files in a subdirectory by deleting and recreating it.
**`import_map_file(directory)`** Copies a file from an arbitrary path on the filesystem into the `maps/` subdirectory. Used when the operator imports a new map via the file picker. The original filename is preserved.
**`save_snapshot(port, file_name)`** Captures a single JPEG frame from an MJPEG stream (given by its localhost URL/port) and saves it to the `images/` directory as `{file_name}.jpg`. Used in the Science task to photograph samples. It scans the raw HTTP stream for the JPEG start marker (`0xFF 0xD8`) and end marker (`0xFF 0xD9`), extracting the first complete frame. Has a 5 MB safety limit per frame.