chatbot.py

"""
CodeAlpha_BasicChatbot
Task 4: Basic Rule-Based Chatbot (Advanced Version 2)
Concepts: if-elif, functions, loops, input/output, re, json, datetime

Features:
  - Rule-based responses using keyword matching (regex)
  - Remembers the user's name during the conversation
  - Simple calculator (add, subtract, multiply, divide)
  - Wider topics: weather, food, hobbies, mood, jokes
  - Persistent chat history saved to JSON (view past conversations)
  - Colorful terminal UI
"""

import re
import random
import json
import os
from datetime import datetime


# ---------- Colors ----------
class C:
    HEADER = "\033[95m"
    CYAN = "\033[96m"
    GREEN = "\033[92m"
    YELLOW = "\033[93m"
    RED = "\033[91m"
    BLUE = "\033[94m"
    BOLD = "\033[1m"
    END = "\033[0m"


BOT_NAME = "CodeBot"
HISTORY_FILE = "chatbot_history.json"


# ---------- Persistent history (JSON) ----------
def load_history():
    if os.path.exists(HISTORY_FILE):
        try:
            with open(HISTORY_FILE, "r", encoding="utf-8") as f:
                return json.load(f)
        except (json.JSONDecodeError, IOError):
            return []
    return []


def save_history(all_sessions):
    try:
        with open(HISTORY_FILE, "w", encoding="utf-8") as f:
            json.dump(all_sessions, f, indent=2)
    except (IOError, OSError) as e:
        print(f"{C.RED}Could not save history: {e}{C.END}")


def show_past_conversations(all_sessions):
    if not all_sessions:
        print(f"{C.YELLOW}No past conversations found.{C.END}")
        return

    print(f"\n{C.BOLD}Past Conversations:{C.END}")
    for i, session in enumerate(all_sessions, start=1):
        print(f"  {i}. {session['date']} ({len(session['messages'])} messages)"
              f"{' - ' + session['user_name'] if session.get('user_name') else ''}")

    choice = input("\nEnter a number to view that conversation (or press Enter to skip): ").strip()
    if choice.isdigit() and 1 <= int(choice) <= len(all_sessions):
        session = all_sessions[int(choice) - 1]
        print(f"\n{C.CYAN}--- Conversation from {session['date']} ---{C.END}")
        for speaker, msg in session["messages"]:
            color = C.BOLD if speaker == "You" else C.GREEN
            print(f"{color}{speaker}: {msg}{C.END}")
        print(f"{C.CYAN}--- End of conversation ---{C.END}\n")


# ---------- Simple calculator ----------
def try_calculate(text):
    match = re.search(
        r"(-?\d+(?:\.\d+)?)\s*([\+\-\*x×/])\s*(-?\d+(?:\.\d+)?)", text
    )
    if not match:
        return None

    num1 = float(match.group(1))
    op = match.group(2)
    num2 = float(match.group(3))

    try:
        if op == "+":
            result = num1 + num2
        elif op == "-":
            result = num1 - num2
        elif op in ("*", "x", "×"):
            result = num1 * num2
        elif op == "/":
            if num2 == 0:
                return "I can't divide by zero!"
            result = num1 / num2
        else:
            return None

        if result == int(result):
            result = int(result)
        return f"That equals {result}."
    except (ValueError, ZeroDivisionError):
        return "Sorry, I couldn't calculate that."


# ---------- Rules ----------
RULES = [
    (r"\b(hi|hello|hey|hii+|helo)\b",
     ["Hi there! How can I help you today?",
      "Hello! Nice to see you.",
      "Hey! What's up?"]),

    (r"\bhow are you\b",
     ["I'm fine, thanks for asking! How about you?",
      "Doing great! Just here chatting with you.",
      "I'm a bot, so I'm always doing well :)"]),

    (r"\b(i am|i'm) (fine|good|great|okay|ok|happy)\b",
     ["Glad to hear that!", "Awesome, good to know!"]),

    (r"\b(i am|i'm) (sad|tired|upset|not okay|not good|down)\b",
     ["I'm sorry to hear that. I hope things get better soon.",
      "Take care of yourself. Want to talk about it?"]),

    (r"\bwhat('?s| is) your name\b",
     [f"I'm {BOT_NAME}, your friendly rule-based chatbot.",
      f"You can call me {BOT_NAME}!"]),

    (r"\bwho (made|created|built) you\b",
     ["I was built as part of a CodeAlpha Python internship project!"]),

    (r"\bwhat can you do\b",
     ["I can chat, remember your name, do basic math (try '5 + 3'), "
      "tell jokes, show past conversations, or just have a casual chat!"]),

    (r"\b(thank you|thanks|thankyou)\b",
     ["You're welcome!", "Anytime!", "No problem at all!"]),

    (r"\b(help|assist)\b",
     ["Sure! Ask me about the time, date, do some math, tell you a joke, "
      "or just chat. Type 'bye' to end our chat."]),

    (r"\b(joke|funny)\b",
     ["Why do programmers prefer dark mode? Because light attracts bugs!",
      "Why did the Python developer wear glasses? Because they couldn't C!",
      "I would tell you a UDP joke, but you might not get it."]),

    (r"\byour age\b|\bhow old are you\b",
     ["I don't have an age - I'm just lines of Python code!"]),

    (r"\b(love|like) (you|this)\b",
     ["That's sweet of you to say!"]),

    (r"\bweather\b",
     ["I can't check live weather right now, but I hope it's nice where you are!",
      "No live weather access here, but stay prepared either way!"]),

    (r"\b(food|hungry|eat)\b",
     ["I don't eat, but I hear pizza is popular among humans!",
      "Food sounds great - what's your favorite dish?"]),

    (r"\b(hobby|hobbies|free time)\b",
     ["I like chatting with people! What do you enjoy doing?"]),

    (r"\b(movie|film|series|show)\b",
     ["I don't watch movies, but I'd love to hear your favorite one!"]),

    (r"\b(music|song)\b",
     ["Music sounds fun! What genre do you like?"]),

    (r"\bstudy|exam|college|internship\b",
     ["Studying and internships build great skills - keep going, you're doing well!"]),
]

FALLBACK_RESPONSES = [
    "I'm not sure I understand. Could you rephrase that?",
    "Hmm, I don't have an answer for that yet.",
    "Sorry, I didn't quite get that. Try asking something else!",
    "I'm still learning - can you try a different question?",
]


def get_response(user_input, user_name):
    text = user_input.lower().strip()

    if not text:
        return "Please say something!", user_name

    calc_result = try_calculate(text)
    if calc_result and re.search(r"\d+\s*[\+\-\*x×/]\s*\d+", text):
        return calc_result, user_name

    name_match = re.search(
        r"my name is (\w+)|i am (\w+)|i'm (\w+)|call me (\w+)", text
    )
    if name_match:
        name = next(g for g in name_match.groups() if g)
        name = name.capitalize()
        if name.lower() not in ("fine", "good", "great", "okay", "ok", "happy",
                                 "sad", "tired", "upset", "down", "not"):
            return f"Nice to meet you, {name}! I'll remember your name.", name

    if re.search(r"what('?s| is) my name", text):
        if user_name:
            return f"Your name is {user_name}!", user_name
        return "I don't know your name yet - tell me by saying 'my name is ...'.", user_name

    if re.search(r"\b(bye|goodbye|see you|exit|quit)\b", text):
        farewell = f"Goodbye, {user_name}! Take care!" if user_name else "Goodbye! Take care!"
        return farewell, user_name

    if re.search(r"time is it|current time", text):
        return f"The current time is {datetime.now().strftime('%I:%M %p')}.", user_name

    if re.search(r"the date|today'?s date", text):
        return f"Today's date is {datetime.now().strftime('%d %B %Y')}.", user_name

    for pattern, responses in RULES:
        if re.search(pattern, text):
            return random.choice(responses), user_name

    return random.choice(FALLBACK_RESPONSES), user_name


def is_exit_command(text):
    return bool(re.search(r"\b(bye|goodbye|exit|quit|see you)\b", text.lower()))


def main():
    print(f"{C.HEADER}{C.BOLD}" + "=" * 50 + C.END)
    print(f"{C.HEADER}{C.BOLD}" + " " * 14 + f"{BOT_NAME} - CHATBOT" + C.END)
    print(f"{C.HEADER}{C.BOLD}" + "=" * 50 + C.END)
    print(f"{C.CYAN}Tip: try 'my name is Alex', '5 + 3', or 'tell me a joke'.{C.END}")
    print(f"{C.CYAN}Type 'history' to see past chats, 'bye' or 'quit' to exit.{C.END}\n")

    all_sessions = load_history()

    first_input = input(f"{C.BOLD}You: {C.END}").strip()
    conversation_log = []
    user_name = None

    if first_input.lower() == "history":
        show_past_conversations(all_sessions)
        first_input = input(f"{C.BOLD}You: {C.END}").strip()

    try:
        user_input = first_input
        while True:
            if not user_input:
                print(f"{C.YELLOW}{BOT_NAME}: Please type something!{C.END}")
                user_input = input(f"{C.BOLD}You: {C.END}").strip()
                continue

            if user_input.lower() == "history":
                show_past_conversations(all_sessions)
                user_input = input(f"{C.BOLD}You: {C.END}").strip()
                continue

            conversation_log.append(("You", user_input))
            response, user_name = get_response(user_input, user_name)
            print(f"{C.GREEN}{BOT_NAME}: {response}{C.END}")
            conversation_log.append((BOT_NAME, response))

            if is_exit_command(user_input):
                break

            user_input = input(f"{C.BOLD}You: {C.END}").strip()

    except KeyboardInterrupt:
        print(f"\n{C.YELLOW}(Chat interrupted){C.END}")
        farewell = f"Goodbye, {user_name}! Take care!" if user_name else "Goodbye! Take care!"
        print(f"{C.GREEN}{BOT_NAME}: {farewell}{C.END}")

    if conversation_log:
        all_sessions.append({
            "date": datetime.now().strftime("%Y-%m-%d %H:%M:%S"),
            "user_name": user_name,
            "messages": conversation_log,
        })
        save_history(all_sessions)
        print(f"{C.CYAN}(Conversation saved to {HISTORY_FILE}){C.END}")


if __name__ == "__main__":
    main()