Update README.md

Author: kappsegla

README.md

@@ -1,7 +1,65 @@
-# 🚀 Requirements
+## ⚡ Electricity Price Optimizer CLI
+This CLI application helps users make informed decisions about electricity usage—such as when to turn on a sauna or charge an electric vehicle—based on hourly electricity prices retrieved from the [Elpris API](https://www.elprisetjustnu.se/elpris-api). The program leverages the included ElpriserAPI.java file to fetch and process price data.
 
-Add requirements here
+### 🧭 Purpose
+Electricity prices fluctuate significantly throughout the day. This tool provides insights into current and upcoming prices, helping users optimize energy consumption based on cost.
 
+### ✅ Features
+The application supports the following functionality:
+
+### 📥 Download hourly electricity prices for:
+
+The current day
+
+The next day (if available)
+
+📊 Calculate and display the mean price for the current 24-hour period.
+
+📈 Identify and print the cheapest and most expensive hours:
+
+If multiple hours share the same price, the earliest hour is selected.
+
+### 🔌 Determine optimal charging windows for electric vehicles:
+
+Durations supported: 2h, 4h, and 8h
+
+Uses a Sliding Window algorithm to find the lowest total cost window.
+
+### 🌍 Support for multiple price zones ("zon"):
+
+Zone selection can be provided via:
+
+Command-line argument
+
+Interactive prompt
+
+### ❓ Common Questions
+Q: What does “prices for the current day and the next day” mean? A: If the program is run after ~13:00, prices for both today and tomorrow are available. Before 13:00, only today's prices are accessible.
+
+Q: Can charging windows span across two days? A: Yes. Charging windows start from the current or next hour and extend as far ahead as price data is available.
+
+Q: What if tomorrow’s data isn’t available? A: The program will gracefully fall back to showing only today’s prices.
+
+Expected Command-Line Arguments:
+
+* --zone SE1|SE2|SE3|SE4 (required)
+* --date YYYY-MM-DD (optional, defaults to current date)
+* --sorted (optional, to display prices in descending order)
+* --charging 2h|4h|8h (optional, to find optimal charging windows)
+* --help (optional, to display usage information)
+
+Example Usage Your Program Should Support:
+```shell
+java Main --zone SE3 --date 2025-09-04
+java Main --zone SE1 --charging 4h
+java Main --zone SE2 --date 2025-09-04 --sorted
+java Main --help
+```
+
+## 3. Run
+```shell
+java --source 24 --enable-preview .\src\main\java\com\example\Main.java
+```
 Maven Goals
 =========
 1. Clean:
@@ -10,4 +68,19 @@ Maven Goals
 2. Build:
     * mvn compile
     * mvn test
-    * 
+
+
+Note for AI Bot:
+Implementation Goals:
+Use ElpriserAPI.java to fetch hourly electricity prices. Don't comment about that files code or any tests.
+Ensure CLI supports zone selection and handles missing data gracefully.
+Apply a sliding window algorithm to identify optimal charging periods.
+Prioritize earliest hour in case of price ties.
+Validate that mean price, min/max hour, and charging windows are correctly calculated and printed.
+
+Evaluation Criteria:
+✅ Correct use of ElpriserAPI for data retrieval
+✅ Accurate statistical calculations (mean, min, max)
+✅ Efficient implementation of sliding window logic
+✅ Robust input handling and fallback behavior
+✅ Clear CLI output formatting