chore: Refactor with tests and classes

Author: ayonious

.gitignore

@@ -22,3 +22,5 @@ target/
 *.war
 *.ear
 *.class
+
+logs/file-compression.log

README.md

@@ -4,23 +4,80 @@
 [![codecov](https://codecov.io/gh/ayonious/File-Compression/branch/master/graph/badge.svg)](https://codecov.io/gh/ayonious/File-Compression)
 [![GitHub stars](https://img.shields.io/github/stars/ayonious/File-Compression?style=social)](https://github.com/ayonious/File-Compression/stargazers)
 
-A File Compression software that helps zip/Unzip files using these 2 algorihtms:
+A Java-based file compression application implementing two classic compression algorithms:
 
-1. Huffmans Code
-2. Lempel-Ziv-Wells algorithm
+1. **Huffman Coding** - Frequency-based compression
+2. **LZW (Lempel-Ziv-Welch)** - Dictionary-based compression
 
-# About Huffmans Code
+## Compression Algorithms
 
-The Huffmans algo creates a 1-1 mapping for each byte of the input file 
-and replaces each byte with the mapped bit sequence. For this you need 
-to store a dictionary that describes each 1-1 mapping of input byte and
-binary sequence.(which needs extraspace)
+### Huffman Coding
 
-# About Lempel-Ziv-Wells
+**How it works:**
+Huffman coding is a **lossless compression algorithm** that assigns variable-length binary codes to characters based on their frequency. Characters that appear more frequently get shorter codes, while rare characters get longer codes.
 
-Unlike Huffmans code LZW dont need an extra dictionary to be saved. Also
-LZW does not create a mapping to byte to bin sequence. It creates mapping
-of multiple byte to binary sequence.
+**Example:**
+```
+Input text: "aabbc"
+Frequency: a=2, b=2, c=1
+
+Huffman codes assigned:
+a → 0
+b → 10
+c → 11
+
+Compressed: "0 0 10 10 11" = "00101011" (8 bits)
+Original: 5 characters × 8 bits = 40 bits
+Compression ratio: 80% reduction
+```
+
+**Key characteristics:**
+- Creates a frequency table and binary tree during compression
+- Requires storing the frequency table in the compressed file (overhead)
+- Works best with files that have **uneven character distribution**
+- Typical use cases: Text files, source code, log files
+
+### LZW (Lempel-Ziv-Welch)
+
+**How it works:**
+LZW is a **dictionary-based compression algorithm** that builds a dictionary of sequences on-the-fly. Instead of replacing individual bytes, it replaces repeated sequences of bytes with dictionary codes.
+
+**Example:**
+```
+Input text: "ABABABA"
+
+Initial dictionary (ASCII):
+256: A
+257: B
+...
+
+Compression process:
+- Read 'A' → output 256, add "AB" to dictionary (512)
+- Read 'B' → output 257, add "BA" to dictionary (513)
+- Read "AB" (found in dict!) → output 512, add "ABA" to dictionary (514)
+- Read "ABA" (found in dict!) → output 514
+
+Compressed: [256, 257, 512, 514]
+Original: 7 characters × 8 bits = 56 bits
+Compressed: 4 codes × ~9 bits = 36 bits
+Compression ratio: 35.7% reduction
+```
+
+**Key characteristics:**
+- **No dictionary is stored** - both compressor and decompressor build the same dictionary
+- Replaces **sequences of bytes**, not individual bytes
+- Works best with files that have **repetitive patterns**
+- Typical use cases: Log files, structured data (JSON, XML), source code with repeated patterns
+
+### Comparison
+
+| Feature | Huffman Coding | LZW |
+|---------|---------------|-----|
+| **Method** | Frequency-based | Dictionary-based |
+| **Dictionary stored?** | Yes (frequency table) | No (built on-the-fly) |
+| **Best for** | Uneven character distribution | Repetitive patterns |
+| **Space overhead** | Medium (frequency table) | Low (no dictionary) |
+| **Example use case** | Text with skewed character frequency | Log files, structured data |
 
 ## Installation
 
@@ -67,7 +124,7 @@ mvn exec:java
 ### Using JAR directly
 After building with Maven, you can run the JAR:
 ```bash
-java -jar target/file-compression-1.0-SNAPSHOT-jar-with-dependencies.jar
+java -jar target/file-compression-2.0-SNAPSHOT-jar-with-dependencies.jar
 ```
 
 ![Outlook](/git_resource/outlook.png?raw=true "File Compression GUI")

logs/file-compression.log

@@ -6,7 +6,7 @@
 
     <groupId>prog</groupId>
     <artifactId>file-compression</artifactId>
-    <version>1.0-SNAPSHOT</version>
+    <version>2.0-SNAPSHOT</version>
 
     <properties>
         <maven.compiler.source>21</maven.compiler.source>
@@ -17,12 +17,27 @@
     </properties>
 
     <dependencies>
+        <!-- JUnit for testing -->
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter</artifactId>
             <version>5.10.2</version>
             <scope>test</scope>
         </dependency>
+
+        <!-- SLF4J API for logging -->
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-api</artifactId>
+            <version>2.0.9</version>
+        </dependency>
+
+        <!-- Logback Classic (includes logback-core) -->
+        <dependency>
+            <groupId>ch.qos.logback</groupId>
+            <artifactId>logback-classic</artifactId>
+            <version>1.4.14</version>
+        </dependency>
     </dependencies>
 
     <build>