from tkinter import filedialog, messagebox

import customtkinter as ctk
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
from matplotlib.figure import Figure

from app.database import get_connection


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

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

        self._build_header()
        self._build_left_panel()
        self._build_right_panel()

    def _build_header(self) -> None:
        header_frame = ctk.CTkFrame(self, fg_color="transparent")
        header_frame.grid(row=0, column=0, columnspan=2, sticky="ew", padx=8, pady=(8, 12))
        header_frame.grid_columnconfigure(0, weight=1)

        title = ctk.CTkLabel(
            header_frame,
            text="Аналитика и отчёты",
            font=ctk.CTkFont(size=28, weight="bold"),
        )
        title.grid(row=0, column=0, sticky="w")

        export_button = ctk.CTkButton(
            header_frame,
            text="Сохранить отчёт в TXT",
            command=self.export_report,
        )
        export_button.grid(row=0, column=1, padx=(12, 0))

    def _build_left_panel(self) -> None:
        left_frame = ctk.CTkFrame(self, corner_radius=18)
        left_frame.grid(row=1, column=0, sticky="nsew", padx=(8, 12), pady=8)
        left_frame.grid_rowconfigure(1, weight=1)
        left_frame.grid_columnconfigure(0, weight=1)

        info_label = ctk.CTkLabel(
            left_frame,
            text="Текстовый отчёт за текущий месяц",
            font=ctk.CTkFont(size=20, weight="bold"),
        )
        info_label.grid(row=0, column=0, sticky="w", padx=18, pady=(18, 8))

        self.report_box = ctk.CTkTextbox(left_frame)
        self.report_box.grid(row=1, column=0, sticky="nsew", padx=18, pady=(0, 18))

    def _build_right_panel(self) -> None:
        right_frame = ctk.CTkFrame(self, corner_radius=18)
        right_frame.grid(row=1, column=1, sticky="nsew", padx=(0, 8), pady=8)
        right_frame.grid_rowconfigure(1, weight=1)
        right_frame.grid_columnconfigure(0, weight=1)

        chart_label = ctk.CTkLabel(
            right_frame,
            text="Структура расходов по категориям",
            font=ctk.CTkFont(size=20, weight="bold"),
        )
        chart_label.grid(row=0, column=0, sticky="w", padx=18, pady=(18, 8))

        self.chart_container = ctk.CTkFrame(right_frame, fg_color="transparent")
        self.chart_container.grid(row=1, column=0, sticky="nsew", padx=18, pady=(0, 18))

        self.figure = Figure(figsize=(5, 4), dpi=100)
        self.canvas = FigureCanvasTkAgg(self.figure, master=self.chart_container)
        self.canvas.get_tk_widget().pack(fill="both", expand=True)

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

            summary = cursor.execute(
                """
                SELECT
                    COALESCE(SUM(CASE WHEN transaction_type = 'Доход' THEN amount END), 0) AS income,
                    COALESCE(SUM(CASE WHEN transaction_type = 'Расход' THEN amount END), 0) AS expense
                FROM transactions
                WHERE strftime('%Y-%m', created_at) = strftime('%Y-%m', 'now')
                """
            ).fetchone()

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

            subscription_total = cursor.execute(
                """
                SELECT COALESCE(
                    SUM(
                        CASE
                            WHEN period = 'Год' THEN amount / 12.0
                            ELSE amount
                        END
                    ),
                    0
                ) AS total
                FROM subscriptions
                WHERE status = 'Активна'
                """
            ).fetchone()["total"]

            category_rows = cursor.execute(
                """
                SELECT c.name,
                       SUM(t.amount) AS total
                FROM transactions AS t
                JOIN categories AS c ON c.id = t.category_id
                WHERE t.transaction_type = 'Расход'
                  AND strftime('%Y-%m', t.created_at) = strftime('%Y-%m', 'now')
                GROUP BY c.name
                HAVING total > 0
                ORDER BY total DESC
                """
            ).fetchall()

        net_result = summary["income"] - summary["expense"]
        top_category = category_rows[0]["name"] if category_rows else "Нет данных"
        top_category_value = category_rows[0]["total"] if category_rows else 0

        report_text = (
            "ОТЧЁТ ЗА ТЕКУЩИЙ МЕСЯЦ\n\n"
            f"Доходы: {summary['income']:,.2f} ₽\n"
            f"Расходы: {summary['expense']:,.2f} ₽\n"
            f"Финансовый результат: {net_result:,.2f} ₽\n"
            f"Общий баланс по всем счетам: {balance:,.2f} ₽\n"
            f"Активные подписки в пересчёте на месяц: {subscription_total:,.2f} ₽\n"
            f"Самая затратная категория: {top_category} ({top_category_value:,.2f} ₽)\n"
        ).replace(",", " ")

        self.last_report_text = report_text
        self.report_box.delete("1.0", "end")
        self.report_box.insert("1.0", report_text)

        self.figure.clear()
        axis = self.figure.add_subplot(111)
        axis.set_title("Расходы по категориям")

        if category_rows:
            labels = [row["name"] for row in category_rows]
            values = [row["total"] for row in category_rows]
            axis.pie(values, labels=labels, autopct="%1.1f%%")
        else:
            axis.text(0.5, 0.5, "Нет данных для диаграммы", ha="center", va="center")
            axis.axis("off")

        self.canvas.draw()

    def export_report(self) -> None:
        if not self.last_report_text:
            messagebox.showinfo("Информация", "Сначала обновите отчёт.")
            return

        file_path = filedialog.asksaveasfilename(
            defaultextension=".txt",
            filetypes=[("Text files", "*.txt")],
            title="Сохранить отчёт",
        )

        if not file_path:
            return

        with open(file_path, "w", encoding="utf-8") as file:
            file.write(self.last_report_text)

        messagebox.showinfo("Готово", "Отчёт сохранён.")