# Bash Data Viewer

A TUI (Text-based User Interface) tool, written purely in Bash, for displaying CSV, TSV, or JSON data. The display refreshes at a configurable interval, inspired by tools like bashtop.

## Features

*   Displays CSV, TSV, and JSON data in a tabular format.
*   Configurable refresh interval for the data display.
*   Basic TUI for easy viewing in the terminal.
*   Error handling for file issues and unsupported formats.

## Dependencies

*   **Bash**: Version 4.4 or later.
*   **jq**: Required for parsing JSON files. You can usually install it via your system's package manager (e.g., `sudo apt install jq`, `sudo yum install jq`, `brew install jq`).

## Usage

To use the Bash Data Viewer, run the script from your terminal:

```shell
./dataviewer.sh [path_to_data_file] [refresh_interval_seconds]
```

**Arguments:**

*   `path_to_data_file` (optional): The path to the CSV, TSV, or JSON file you want to display.
    *   If not provided, the TUI will launch and show "No input file specified."
*   `refresh_interval_seconds` (optional): The time in seconds between display refreshes.
    *   Defaults to 5 seconds if not provided.
    *   Must be a positive integer.

**Examples:**

*   Display a CSV file with a 2-second refresh interval:
    ```shell
    ./dataviewer.sh data.csv 2
    ```
*   Display a JSON file with the default 5-second refresh interval:
    ```shell
    ./dataviewer.sh logs.json
    ```
*   Launch the TUI without an initial file (it will show an appropriate message):
    ```shell
    ./dataviewer.sh
    ```

## Supported Data Formats

### CSV (Comma-Separated Values)
*   File extension must be `.csv`.
*   The first line is treated as the header row.
*   Uses comma (`,`) as the delimiter.

### TSV (Tab-Separated Values)
*   File extension must be `.tsv`.
*   The first line is treated as the header row.
*   Uses tab (`\t`) as the delimiter.

### JSON (JavaScript Object Notation)
*   File extension must be `.json`.
*   Requires `jq` to be installed.
*   **Supported Structures:**
    1.  **Array of Objects**:
        *   Example: `[{"name": "Alice", "age": 30}, {"name": "Bob", "age": 24}]`
        *   The keys of the first object in the array are used as headers.
        *   Each object in the array is displayed as a row.
    2.  **Single Object**:
        *   Example: `{"hostname": "server1", "ip": "192.168.1.10", "status": "running"}`
        *   The keys of the object are used as headers.
        *   The object's values are displayed as a single data row.
    3.  **Empty Array**:
        *   Example: `[]`
        *   Displays an info message: "Info: JSON file is an empty array []".
*   Other JSON structures (e.g., simple arrays of strings/numbers, nested complex objects without a clear tabular mapping) might show an "Unsupported JSON structure" error or may not display as intended.

## Controls

*   **`q`**: Quit the application.
*   **`r`**: Manually re-parse the input file and refresh the display. This is useful if the data file has been updated.

## Error Handling

The TUI will display messages for common errors, such as:
*   File not found.
*   Unknown file type.
*   `jq` not installed (for JSON files).
*   Empty or invalid JSON files.
*   Unsupported JSON structures.

## TODO / Potential Future Enhancements
*   More sophisticated column width calculation (e.g., based on content).
*   Scrolling (up/down, left/right) for larger datasets.
*   Configuration file for persistent settings.
*   Theming support.
*   Search/filter data within the TUI.