controller.py

import tkinter as tk
import tkinter.messagebox as popup
from datetime import datetime, timedelta

class FinanceController:
    def __init__(self, model, view):
        self.model = model
        self.view  = view

        view.add_button.config(command=self.add_transaction)
        view.apply_filter_button.config(command=self.apply_filter)
        view.set_budget_button.config(command=self.set_budget)

        self.refresh()
    
    def add_transaction(self):
        type_       = self.view.type_var.get()
        amount      = self.view.amount_entry.get()
        category    = self.view.category_entry.get()
        description = self.view.desc_entry.get()
        recurrence  = self.view.recurrence_var.get()
        
        if recurrence == "None":
            recurrence = None

        if amount:
            self.model.add_transaction(type_, amount, category, description, recurrence=recurrence)
            popup.showinfo("New Transaction", f"{type_} Transaction added (Amount: ${amount})")

            self.view.amount_entry.delete(0, tk.END)
            self.view.category_entry.delete(0, tk.END)
            self.view.desc_entry.delete(0, tk.END)

            self.refresh()
    
    def apply_filter(self):
        filtered        = self.model.transactions
        type_filter     = self.view.filter_type_var.get()
        category_filter = self.view.filter_category_var.get()

        if type_filter != "All":
            filtered = [t for t in filtered if t["type"] == type_filter]
        
        if category_filter != "All":
            filtered = [t for t in filtered if t["category"] == category_filter]
        
        start = self.view.start_date_entry.get()
        end   = self.view.end_date_entry.get()

        if start != "Start YYYY-MM-DD" and end != "End YYYY-MM-DD":
            filtered = [t for t in filtered if start <= t["date"] <= end]
        
        self.refresh(filtered)
    
    def process_recurring_transactions(self):
        today            = datetime.today().strftime("%Y-%m-%d")
        new_transactions = []

        for t in self.model.transactions:
            if t.get("recurrence") and t["date"] < today:
                last_date = datetime.strptime(t["date"], "%Y-%m-%d")
                next_date = last_date

                if t["recurrence"] == "Daily":
                    next_date += timedelta(days=1)
                
                elif t["recurrence"] == "Weekly":
                    next_date += timedelta(weeks=7)
                
                elif t["recurrence"] == "Monthly":
                    month = last_date.month + 1
                    year  = last_date.year

                    if month > 12:
                        month = 1
                        year  += 1
                    
                    day             = min(last_date.day, 28)
                    next_date       = datetime(year, month, day)
                    next_date_str   = next_date.strftime("%Y-%m-%d")
                
                if next_date_str <= today:
                    new_t           = t.copy()
                    new_t["date"]   = next_date_str
                    t["date"]       = next_date_str

                    new_transactions.append(new_t)
        
        if new_transactions:
            self.models.transactions.extend(new_transactions)
            self.model.save()
    
    def set_budget(self):
        category = self.view.budget_category_entry.get()

        try:
            amount = float(self.view.budget_amount_entry.get())
        except ValueError:
            amount = None

        if category and amount:
            self.model.set_budget(category, amount)
            
            self.view.budget_category_entry.delete(0, tk.END)
            self.view.budget_amount_entry.delete(0, tk.END)

            popup.showinfo("Budget Set", f"Budget set for {category} in amount of ${amount:,.2f}")
    
    def check_budgets(self):
        spending = {}

        for t in self.model.transactions:
            if t["type"] == "Expense":
                spending[t["category"]] = spending.get(t["category"], 0) + t["amount"]

        alerts = []

        for category, budget in self.model.budgets.items():
            spent = spending.get(category, 0)

            if spent >= budget:
                alerts.append(f"{category} is over budget!")
            elif spent >= budget * 0.8:
                alerts.append(f"{category} is nearing budget.")
        
        return alerts
        
    def refresh(self, transactions=None):
        self.process_recurring_transactions()

        if transactions is None:
            transactions = self.model.transactions

        for item in self.view.tree.get_children():
            self.view.tree.delete(item)
        
        for t in transactions:
            self.view.tree.insert("", tk.END, values=(t["type"], f"${t['amount']:,.2f}", t["category"], t["description"], t["date"]))
        
        income  = sum(t["amount"] for t in transactions if t["type"] == "Income")
        expense = sum(t["amount"] for t in transactions if t["type"] == "Expense")
        
        self.view.income_label.config(text=f"Income: ${income:,.2f}")
        self.view.expense_label.config(text=f"Expense: ${expense:,.2f}")
        self.view.balance_label.config(text=f"Balance: ${income - expense:,.2f}")

        # self.view.plot_expense_pie(transactions)
        # self.view.plot_line_balance(transactions)

        alerts = self.check_budgets()
        self.view.alert_label.config(text="\n".join(alerts))