"""
Demo application using pyqt6_scaffold.
Run via start.sh / start.cmd - environment variables must be set.

start.sh:
    export SQLITE_PATH=demo.db
    python demo_app.py
"""
import sys
import sqlite3
from PyQt6.QtWidgets import (
    QApplication, QLabel, QLineEdit,
    QPushButton, QVBoxLayout, QHBoxLayout,
    QWidget, QTableView, QMessageBox
)
from PyQt6.QtCore import Qt

from pyqt6_scaffold import (
    AbstractDatabase, BaseWindow, Composer,
    BaseUser, NavigateRequest, NavigationContext,
    BaseTableModel
)
from pyqt6_scaffold.contrib.auth import Role


# --- Database -----------------------------------------------------------

class AppDatabase(AbstractDatabase):
    @property
    def placeholder(self) -> str:
        return "?"

    def _connect(self):
        import os
        path = os.getenv("SQLITE_PATH", "demo.db")
        conn = sqlite3.connect(path)
        self._bootstrap(conn)
        return conn

    def _bootstrap(self, conn):
        """Create tables and seed data if not exists."""
        conn.executescript("""
            CREATE TABLE IF NOT EXISTS users (
                id       INTEGER PRIMARY KEY,
                login    TEXT UNIQUE,
                password TEXT,
                role     TEXT,
                level    INTEGER
            );

            CREATE TABLE IF NOT EXISTS products (
                id       INTEGER PRIMARY KEY,
                name     TEXT,
                category TEXT,
                price    REAL,
                stock    INTEGER
            );

            INSERT OR IGNORE INTO users VALUES (1, 'admin', 'admin', 'Administrator', 100);
            INSERT OR IGNORE INTO users VALUES (2, 'user',  'user',  'User', 25);

            INSERT OR IGNORE INTO products VALUES (1, 'Notebook',    'Electronics', 79999, 5);
            INSERT OR IGNORE INTO products VALUES (2, 'Mouse',       'Electronics', 1299,  0);
            INSERT OR IGNORE INTO products VALUES (3, 'Table',       'Furniture',   12500, 3);
            INSERT OR IGNORE INTO products VALUES (4, 'Chair',       'Furniture',   8900,  0);
            INSERT OR IGNORE INTO products VALUES (5, 'Monitor',     'Electronics', 24999, 2);
        """)
        conn.commit()

    def auth(self, login: str, password: str) -> BaseUser | None:
        with self.execute(
            f"SELECT id, login, role, level FROM users WHERE login = {self.placeholder} AND password = {self.placeholder}",
            (login, password)
        ) as cursor:
            row = cursor.fetchone()
        if not row:
            return None
        role = Role(name=row[2], level=row[3])
        return BaseUser(id=row[0], name=row[1], role=role)

    def get_products(self) -> list:
        with self.execute(
            "SELECT id, name, category, price, stock FROM products ORDER BY id"
        ) as cursor:
            return cursor.fetchall()


# --- Models -----------------------------------------------------------

class ProductModel(BaseTableModel):
    headers = ["ID", "Name", "Category", "Price", "In stock"]

    def row_background(self, data):
        from PyQt6.QtGui import QColor
        if data[4] == 0:          # if out of stock - blue
            return QColor("#cce5ff")
        return None

    def row_foreground(self, data):
        return None

    def row_font(self, data):
        return None


# --- Windows -----------------------------------------------------------

class LoginWindow(BaseWindow):
    def _define_widgets(self):
        self._title    = QLabel("Entry in system")
        self._login    = QLineEdit()
        self._password = QLineEdit()
        self._password.setEchoMode(QLineEdit.EchoMode.Password)
        self._btn      = QPushButton("Enter")
        self._hint     = QLabel("admin/admin   or   user/user")

        self._login.setPlaceholderText("Login")
        self._password.setPlaceholderText("Password")
        self._hint.setAlignment(Qt.AlignmentFlag.AlignCenter)

    def _tune_layouts(self):
        layout = QVBoxLayout()
        layout.setSpacing(10)
        layout.setContentsMargins(40, 40, 40, 40)
        layout.addWidget(self._title)
        layout.addWidget(self._login)
        layout.addWidget(self._password)
        layout.addWidget(self._btn)
        layout.addWidget(self._hint)

        container = QWidget()
        container.setLayout(layout)
        self.setCentralWidget(container)

    def _connect_slots(self):
        self._btn.clicked.connect(self._on_login)
        self._password.returnPressed.connect(self._on_login)

    def _apply_windows_settings(self):
        self.setWindowTitle("Authorization")
        self.setFixedSize(300, 220)

    def _on_login(self):
        user = self._db.auth(
            self._login.text().strip(),
            self._password.text().strip()
        )
        if user is None:
            QMessageBox.warning(self, "Error", "Incorrect login or password")
            return

        self._composer.navigate_request.emit(
            NavigateRequest(
                target="main",
                context=NavigationContext(data={"user": user})
            )
        )


class MainWindow(BaseWindow):
    def _define_widgets(self):
        user = self._composer.context.data.get("user")
        name = user.name if user else ""
        role = user.role.name if user else ""

        self._info   = QLabel(f"User: {name}  |  Role: {role}")
        self._table  = QTableView()
        self._model  = ProductModel()
        self._logout = QPushButton("Exit")

        self._table.setModel(self._model)
        self._table.horizontalHeader().setStretchLastSection(True)
        self._table.setSelectionBehavior(
            QTableView.SelectionBehavior.SelectRows
        )
        self._table.setEditTriggers(
            QTableView.EditTrigger.NoEditTriggers
        )

        rows = self._db.get_products()
        self._model.refresh(rows)

    def _tune_layouts(self):
        top = QHBoxLayout()
        top.addWidget(self._info)
        top.addStretch()
        top.addWidget(self._logout)

        layout = QVBoxLayout()
        layout.setContentsMargins(16, 16, 16, 16)
        layout.setSpacing(8)
        layout.addLayout(top)
        layout.addWidget(self._table)

        container = QWidget()
        container.setLayout(layout)
        self.setCentralWidget(container)

    def _connect_slots(self):
        self._logout.clicked.connect(self._on_logout)

    def _apply_windows_settings(self):
        self.setWindowTitle("Product catalog")
        self.resize(700, 400)

    def _on_logout(self):
        self._composer.navigate_request.emit(
            NavigateRequest(
                target="login",
                context=NavigationContext()
            )
        )


# --- Entry point -----------------------------------------------------------

def main():
    app = QApplication(sys.argv)

    db = AppDatabase()
    db.connect()

    composer = Composer(app=app, db=db)
    composer.register("login", LoginWindow)
    composer.register("main",  MainWindow)

    sys.exit(composer.run(start="login"))


if __name__ == "__main__":
    main()