# PHP + PostgreSQL Visit Counter

This project implements a PHP web application for counting visits, backed by a PostgreSQL database. It is containerized using Docker and Docker Compose, and provides automated deployment scripts (to Plesk via Git) as well as deployment cleanup scripts.

---

## Table of Contents

1. [Overview](#overview)  
2. [Features](#features)  
3. [Prerequisites](#prerequisites)  
4. [Installation & Configuration](#installation--configuration)  
   - [Project Structure](#project-structure)  
   - [Environment Variables](#environment-variables)  
   - [Docker and Docker Compose](#docker-and-docker-compose)  
   - [Prepare Script (`prepare-app.sh`)](#prepare-script-prepare-appsh)  
5. [Usage](#usage)  
   - [Running Locally](#running-locally)  
   - [Application Entry Point](#application-entry-point)  
   - [Table Reset (`drop.php`)](#table-reset-dropphp)  
6. [Deployment to Plesk](#deployment-to-plesk)  
7. [Deployment Cleanup (`remove-app.sh`)](#deployment-cleanup-remove-appsh)  
8. [Detailed File Structure](#detailed-file-structure)  
9. [Contributing](#contributing)  
10. [Troubleshooting](#troubleshooting)  
11. [License](#license)  

---

## Overview

This simple application counts the number of visits to a web page. On each page load, a new entry is inserted into the `visitors` table in PostgreSQL, and the total count is displayed.

A button allows to choose between light and dark themes via JavaScript and `localStorage`.

The project includes:

- A **PostgreSQL** container with automatic table initialization via `db.sql`.  
- A **PHP 8.2 + Apache** container serving the application.  
- A **Dockerfile** to build the web image (with the `pdo_pgsql` extension installed).  
- A **docker-compose.yml** to orchestrate both services.  
- A **prepare-app.sh** script for force-pushing deployments to Plesk via Git.  
- A **remove-app.sh** script for cleaning up the remote deployment.

---

## Features

- Automatically inserts a row into the `visitors` table on each load (`INSERT INTO visitors DEFAULT VALUES`).  
- Automatically creates the table if it doesn’t exist (`CREATE TABLE IF NOT EXISTS visitors …`).  
- Displays the visit counter.  
- Light/dark theme toggle, persisted in `localStorage`.  
- Automated Git deployments (Plesk).  
- Remote cleanup of pushed content.

---

## Prerequisites

- **Docker** (>= 20.x)  
- **Docker Compose** (>= 1.27.x)  
- **Git** (for the deployment scripts)  
- Access to a Plesk instance with a Git-configured repository (for `prepare-app.sh` and `remove-app.sh`)

---

## Installation & Configuration

### Project Structure

```text
├── db.sql               # SQL script to initialize the `visitors` table
├── Dockerfile           # Builds the PHP + Apache + pdo_pgsql image
├── docker-compose.yml   # Docker orchestration (db + web)
├── prepare-app.sh       # Deployment script to Plesk
├── remove-app.sh        # Remote cleanup script
├── index.php        # Main page (insertion + count + front-end)
└── drop.php         # Script to drop the `visitors` table
```

### Environment Variables

In `docker-compose.yml`, for the **db** service:

```yaml
POSTGRES_DB: visitors
POSTGRES_USER: visitor_user
POSTGRES_PASSWORD: secret
```

And for the **web** service:

```yaml
DB_HOST: db
DB_PORT: 5432
DB_NAME: visitors
DB_USER: visitor_user
DB_PASS: secret
```




### Prepare Script (`prepare-app.sh`)

This script initializes the Git repo (if needed), adds a `tuke` remote pointing to the Plesk instance, commits all changes, then force-pushes the branch (`master` or `main`).

```bash
chmod +x prepare-app.sh
./prepare-app.sh
```


---

## Usage


### Application Entry Point

`index.php` performs:

1. Connects to PostgreSQL via PDO (`pgsql:host=$dbHost;port=$dbPort;dbname=$dbName`).  
2. Runs an embedded SQL migration to create the `visitors` table if it doesn’t exist.  
3. Inserts a new row:
   ```php
   $pdo->exec("INSERT INTO visitors DEFAULT VALUES");
   ```
4. Retrieves the total count:
   ```php
   $count = $pdo->query("SELECT COUNT(*) FROM visitors")->fetchColumn();
   ```
5. Generates the HTML/CSS/JS to display the counter and manage the theme.

### Table Reset (`drop.php`)

The script `drop.php` connects to the same database and runs:

```php
$pdo->exec("DROP TABLE IF EXISTS visitors");
echo "Table visitors dropped.";
```

On error it returns HTTP 500 and displays the exception message.

---

## Deployment to Plesk

To deploy automatically:

1. Configure `GIT_REMOTE_URL` and `BRANCH` in `prepare-app.sh`.  
2. Make it executable and run:
   ```bash
   chmod +x prepare-app.sh
   ./prepare-app.sh
   ```
This force-pushes the branch to Plesk’s `httpdocs`, updating the remote site.

---

## Deployment Cleanup (`remove-app.sh`)

To clear the remote content without touching the local repository:

1. Make it executable:
   ```bash
   chmod +x remove-app.sh
   ```
2. Run:
   ```bash
   ./remove-app.sh
   ```
This clones the remote into a temp directory, removes all tracked files, commits, and force-pushes, then cleans up.

---

## Detailed File Structure

- **docker-compose.yml**: Coordinates two services:  
  - **db** (PostgreSQL 13) initialized via `./db.sql`.  
  - **web** (PHP 8.2 + Apache with pdo_pgsql) linked to `db`, exposing port 8080.  
- **Dockerfile**: Base `php:8.2-apache`, installs `libpq-dev` and `pdo_pgsql`, copies `src/` to `/var/www/html/`.  
- **db.sql**: SQL to auto-create the `visitors` table.  
- **prepare-app.sh** & **remove-app.sh**: Bash scripts for Git-based deployment and cleanup on Plesk.  
- **index.php**: Main page logic (connect, migrate, insert, count, render).  
- **drop.php**: Drops the `visitors` table.

---

## Troubleshooting

- **PostgreSQL connection error**: Ensure the `db` service is running; check logs:
  ```bash
  docker-compose logs db
  ```
- **Table not created**: Make sure `db.sql` is mounted under `/docker-entrypoint-initdb.d/` and that the `db_data` volume is empty (initialization only runs on a fresh volume).  
- **Git push rejected**: Verify remote URL and credentials in `prepare-app.sh`.