import calendar
from datetime import date

import customtkinter as ctk

from app.database import get_connection


class DashboardFrame(ctk.CTkFrame):
    def __init__(self, master, refresh_callback) -> None:
        super().__init__(master)
        self.refresh_callback = refresh_callback

        self.grid_columnconfigure((0, 1), weight=1)
        self.grid_rowconfigure(2, weight=1)

        header = ctk.CTkLabel(
            self,
            text="Главная панель",
            font=ctk.CTkFont(size=28, weight="bold"),
        )
        header.grid(row=0, column=0, columnspan=2, sticky="w", padx=8, pady=(8, 16))

        self.balance_card = self._create_card(1, 0, "Общий баланс")
        self.month_expense_card = self._create_card(1, 1, "Расходы за месяц")
        self.month_income_card = self._create_card(2, 0, "Доходы за месяц")
        self.subscriptions_card = self._create_card(2, 1, "Активные подписки")

        self.upcoming_frame = ctk.CTkScrollableFrame(self, label_text="Ближайшие списания")
        self.upcoming_frame.grid(
            row=3,
            column=0,
            columnspan=2,
            sticky="nsew",
            padx=8,
            pady=(16, 8),
        )

    def _create_card(self, row: int, column: int, title: str) -> ctk.CTkLabel:
        card = ctk.CTkFrame(self, corner_radius=18)
        card.grid(row=row, column=column, sticky="nsew", padx=8, pady=8)

        title_label = ctk.CTkLabel(
            card,
            text=title,
            text_color="gray75",
            font=ctk.CTkFont(size=15),
        )
        title_label.pack(anchor="w", padx=18, pady=(16, 8))

        value_label = ctk.CTkLabel(
            card,
            text="0 ₽",
            font=ctk.CTkFont(size=30, weight="bold"),
        )
        value_label.pack(anchor="w", padx=18, pady=(0, 16))
        return value_label

    def refresh_data(self) -> None:
        with get_connection() as connection:
            cursor = connection.cursor()

            balance = cursor.execute(
                "SELECT COALESCE(SUM(balance), 0) AS total FROM accounts"
            ).fetchone()["total"]

            month_expense = cursor.execute(
                """
                SELECT COALESCE(SUM(amount), 0) AS total
                FROM transactions
                WHERE transaction_type = 'Расход'
                  AND strftime('%Y-%m', created_at) = strftime('%Y-%m', 'now')
                """
            ).fetchone()["total"]

            month_income = cursor.execute(
                """
                SELECT COALESCE(SUM(amount), 0) AS total
                FROM transactions
                WHERE transaction_type = 'Доход'
                  AND strftime('%Y-%m', created_at) = strftime('%Y-%m', 'now')
                """
            ).fetchone()["total"]

            subscriptions = cursor.execute(
                """
                SELECT COUNT(*) AS total_count,
                       COALESCE(
                           SUM(
                               CASE
                                   WHEN period = 'Год' THEN amount / 12.0
                                   ELSE amount
                               END
                           ),
                           0
                       ) AS monthly_total
                FROM subscriptions
                WHERE status = 'Активна'
                """
            ).fetchone()

            self.balance_card.configure(text=f"{balance:,.2f} ₽".replace(",", " "))
            self.month_expense_card.configure(
                text=f"{month_expense:,.2f} ₽".replace(",", " ")
            )
            self.month_income_card.configure(
                text=f"{month_income:,.2f} ₽".replace(",", " ")
            )
            self.subscriptions_card.configure(
                text=(
                    f"{subscriptions['total_count']} шт. / "
                    f"{subscriptions['monthly_total']:,.2f} ₽"
                ).replace(",", " ")
            )

            items = cursor.execute(
                """
                SELECT id, name, amount, billing_day, period
                FROM subscriptions
                WHERE status = 'Активна'
                ORDER BY billing_day
                """
            ).fetchall()

        for widget in self.upcoming_frame.winfo_children():
            widget.destroy()

        if not items:
            empty_label = ctk.CTkLabel(
                self.upcoming_frame,
                text="Нет активных подписок.",
                text_color="gray70",
            )
            empty_label.pack(anchor="w", padx=10, pady=10)
            return

        for item in items:
            days_left, next_date_text = self._get_next_payment_info(item["billing_day"])
            card = ctk.CTkFrame(self.upcoming_frame, corner_radius=14)
            card.pack(fill="x", padx=6, pady=6)

            title = ctk.CTkLabel(
                card,
                text=item["name"],
                font=ctk.CTkFont(size=18, weight="bold"),
            )
            title.pack(anchor="w", padx=14, pady=(12, 4))

            info = ctk.CTkLabel(
                card,
                text=(
                    f"{item['amount']:,.2f} ₽ | {item['period']} | "
                    f"следующее списание: {next_date_text} | через {days_left} дн."
                ).replace(",", " "),
                text_color="gray75",
            )
            info.pack(anchor="w", padx=14, pady=(0, 12))

    @staticmethod
    def _get_next_payment_info(billing_day: int) -> tuple[int, str]:
        today = date.today()
        current_last_day = calendar.monthrange(today.year, today.month)[1]
        safe_day = min(billing_day, current_last_day)
        candidate = date(today.year, today.month, safe_day)

        if candidate < today:
            next_month = today.month + 1
            next_year = today.year
            if next_month == 13:
                next_month = 1
                next_year += 1
            next_last_day = calendar.monthrange(next_year, next_month)[1]
            safe_day = min(billing_day, next_last_day)
            candidate = date(next_year, next_month, safe_day)

        days_left = (candidate - today).days
        return days_left, candidate.strftime("%d.%m.%Y")