"""
serial_display.py — QPad XIAO RP2040 companion (PyQt6)
────────────────────────────────────────────────────────
Type text → press Send (or Enter) → text appears on the OLED.
Touch a button on the QPad → the matching shape in the GUI lights up.

Serial protocol (matches serial-display.ino):
  PC → Arduino  "0,<text>\\n"          display text (use | for newlines)
  Arduino → PC  "1,<index>,<0|1>\\n"   button state change

Button indices:  0=A  1=B  2=DOWN  3=LEFT  4=RIGHT  5=UP

Requirements:
  pip install PyQt6 pyserial
"""

import sys
import serial
import serial.tools.list_ports
from PyQt6.QtWidgets import (
    QApplication, QMainWindow, QWidget, QHBoxLayout, QVBoxLayout,
    QPushButton, QLineEdit, QLabel, QComboBox, QStatusBar, QFrame
)
from PyQt6.QtCore import Qt, QTimer, QPointF, pyqtSignal
from PyQt6.QtGui import (
    QPainter, QColor, QPen, QBrush, QRadialGradient, QFont, QFontMetrics
)

# ── Button metadata ────────────────────────────────────────────────────────────

BUTTON_NAMES  = ["A", "B", "DOWN", "LEFT", "RIGHT", "UP"]
BUTTON_LABELS = ["A", "B", "▼",   "◄",   "►",    "▲"]
BUTTON_COLORS_ON  = [
    QColor(80,  220, 80),   # A  – green
    QColor(220,  60, 60),   # B  – red
    QColor(80,  160, 255),  # DOWN
    QColor(80,  160, 255),  # LEFT
    QColor(80,  160, 255),  # RIGHT
    QColor(80,  160, 255),  # UP
]
BUTTON_COLORS_OFF = QColor(60, 60, 60)

NUM_BUTTONS = len(BUTTON_NAMES)


# ── Single button widget ───────────────────────────────────────────────────────

class PadButton(QWidget):
    """A circular indicator that lights up when the physical pad is pressed."""

    RADIUS = 30

    def __init__(self, index: int, parent=None):
        super().__init__(parent)
        self.index   = index
        self.pressed = False
        side = (self.RADIUS + 20) * 2
        self.setFixedSize(side, side)

    def setState(self, pressed: bool):
        if self.pressed != pressed:
            self.pressed = pressed
            self.update()

    def paintEvent(self, event):
        p = QPainter(self)
        p.setRenderHint(QPainter.RenderHint.Antialiasing)

        cx = self.width()  / 2
        cy = self.height() / 2
        r  = self.RADIUS

        if self.pressed:
            # Glow rings
            for glow_r, alpha in [(r + 18, 40), (r + 10, 70)]:
                grad = QRadialGradient(cx, cy, glow_r)
                c = QColor(BUTTON_COLORS_ON[self.index])
                c.setAlpha(alpha)
                grad.setColorAt(0, c)
                grad.setColorAt(1, QColor(0, 0, 0, 0))
                p.setBrush(QBrush(grad))
                p.setPen(Qt.PenStyle.NoPen)
                p.drawEllipse(QPointF(cx, cy), glow_r, glow_r)

            # Filled circle
            p.setBrush(QBrush(BUTTON_COLORS_ON[self.index]))
            p.setPen(QPen(BUTTON_COLORS_ON[self.index].lighter(150), 2))
        else:
            p.setBrush(QBrush(BUTTON_COLORS_OFF))
            p.setPen(QPen(QColor(100, 100, 100), 2))

        p.drawEllipse(QPointF(cx, cy), r, r)

        # Label
        font = QFont("SansSerif", 13, QFont.Weight.Bold)
        p.setFont(font)
        p.setPen(QPen(QColor(20, 20, 20) if self.pressed else QColor(180, 180, 180)))
        p.drawText(self.rect(), Qt.AlignmentFlag.AlignCenter, BUTTON_LABELS[self.index])


# ── D-pad + action button panel ───────────────────────────────────────────────

class ButtonPanel(QWidget):
    """Lays out six PadButton widgets in a gamepad-style arrangement."""

    def __init__(self, parent=None):
        super().__init__(parent)
        self.buttons = [PadButton(i) for i in range(NUM_BUTTONS)]

        # Use an absolute-position container for the gamepad layout
        self.setFixedSize(560, 200)
        self._place_buttons()

    def _place_buttons(self):
        """Position each button widget manually (gamepad layout)."""
        # D-pad centre
        dpad_cx, dpad_cy = 190, 100
        step = 72
        # index: 5=UP 2=DOWN 3=LEFT 4=RIGHT
        positions = {
            5: (dpad_cx,        dpad_cy - step),  # UP
            2: (dpad_cx,        dpad_cy + step),  # DOWN
            3: (dpad_cx - step, dpad_cy),          # LEFT
            4: (dpad_cx + step, dpad_cy),          # RIGHT
            1: (420,            dpad_cy - step),   # B — above A
            0: (420,            dpad_cy + step),   # A — below B
        }
        for idx, (cx, cy) in positions.items():
            btn = self.buttons[idx]
            btn.setParent(self)
            btn.move(cx - btn.width() // 2, cy - btn.height() // 2)

    def setState(self, index: int, pressed: bool):
        if 0 <= index < NUM_BUTTONS:
            self.buttons[index].setState(pressed)

    def resetAll(self):
        for btn in self.buttons:
            btn.setState(False)

    def paintEvent(self, event):
        """Draw subtle cross lines behind the D-pad."""
        p = QPainter(self)
        p.setRenderHint(QPainter.RenderHint.Antialiasing)
        p.setPen(QPen(QColor(55, 55, 55), 2))
        dpad_cx, dpad_cy = 190, 100
        step = 72
        r = PadButton.RADIUS
        p.drawLine(int(dpad_cx - step + r + 4), dpad_cy,
                   int(dpad_cx + step - r - 4), dpad_cy)
        p.drawLine(dpad_cx, int(dpad_cy - step + r + 4),
                   dpad_cx, int(dpad_cy + step - r - 4))


# ── Main window ───────────────────────────────────────────────────────────────

class MainWindow(QMainWindow):

    def __init__(self):
        super().__init__()
        self.setWindowTitle("Serial Display  —  QPad XIAO RP2040")
        self.setFixedSize(600, 480)

        self.serial_port: serial.Serial | None = None
        self._read_buffer = ""

        self._build_ui()
        self._refresh_ports()

        # Poll serial every 20 ms
        self.poll_timer = QTimer(self)
        self.poll_timer.timeout.connect(self._poll_serial)
        self.poll_timer.start(20)

    # ── UI construction ───────────────────────────────────────────────────────

    def _build_ui(self):
        central = QWidget()
        self.setCentralWidget(central)
        root = QVBoxLayout(central)
        root.setSpacing(10)
        root.setContentsMargins(16, 12, 16, 8)

        # ── Serial controls ──
        serial_row = QHBoxLayout()
        self.port_combo = QComboBox()
        self.port_combo.setMinimumWidth(220)
        self.btn_refresh = QPushButton("Refresh")
        self.btn_open    = QPushButton("Open")
        self.btn_close   = QPushButton("Close")
        self.btn_close.setEnabled(False)

        self.btn_refresh.clicked.connect(self._refresh_ports)
        self.btn_open.clicked.connect(self._open_port)
        self.btn_close.clicked.connect(self._close_port)

        serial_row.addWidget(QLabel("Port:"))
        serial_row.addWidget(self.port_combo, 1)
        serial_row.addWidget(self.btn_refresh)
        serial_row.addWidget(self.btn_open)
        serial_row.addWidget(self.btn_close)
        root.addLayout(serial_row)

        # ── Divider ──
        root.addWidget(self._divider())

        # ── Text input ──
        root.addWidget(QLabel("Text to display on QPad OLED:"))
        text_row = QHBoxLayout()
        self.text_input = QLineEdit()
        self.text_input.setPlaceholderText("Type text here… use | for line breaks on the OLED")
        self.text_input.returnPressed.connect(self._send_text)
        self.btn_send = QPushButton("Send")
        self.btn_send.setEnabled(False)
        self.btn_send.clicked.connect(self._send_text)
        text_row.addWidget(self.text_input, 1)
        text_row.addWidget(self.btn_send)
        root.addLayout(text_row)

        # ── Divider ──
        root.addWidget(self._divider())

        # ── Button panel ──
        lbl = QLabel("QPad Buttons")
        lbl.setAlignment(Qt.AlignmentFlag.AlignCenter)
        root.addWidget(lbl)

        self.btn_panel = ButtonPanel()
        root.addWidget(self.btn_panel, alignment=Qt.AlignmentFlag.AlignCenter)

        # ── Status bar ──
        self.status = QStatusBar()
        self.setStatusBar(self.status)
        self.status.showMessage("Select a port and click Open.")

        # ── Stylesheet ──
        self.setStyleSheet("""
            QMainWindow, QWidget { background: #1e1e1e; color: #ddd; font-size: 13px; }
            QComboBox, QLineEdit {
                background: #2d2d2d; border: 1px solid #555;
                border-radius: 4px; padding: 4px 8px; color: #ddd;
            }
            QComboBox:focus, QLineEdit:focus { border-color: #5a9ef0; }
            QPushButton {
                background: #3c6498; border: none; border-radius: 4px;
                padding: 5px 14px; color: #fff;
            }
            QPushButton:hover   { background: #5a82c0; }
            QPushButton:pressed { background: #2a4d7a; }
            QPushButton:disabled { background: #444; color: #888; }
            QLabel { color: #bbb; }
            QStatusBar { background: #252525; color: #aaa; font-size: 12px; }
        """)

    @staticmethod
    def _divider() -> QFrame:
        f = QFrame()
        f.setFrameShape(QFrame.Shape.HLine)
        f.setStyleSheet("color: #3a3a3a;")
        return f

    # ── Serial helpers ────────────────────────────────────────────────────────

    def _refresh_ports(self):
        self.port_combo.clear()
        ports = [p.device for p in serial.tools.list_ports.comports()]
        self.port_combo.addItems(ports)
        self.btn_open.setEnabled(bool(ports))
        self.status.showMessage(
            f"{len(ports)} port(s) found." if ports else "No serial ports found."
        )

    def _open_port(self):
        device = self.port_combo.currentText()
        if not device:
            return
        try:
            self.serial_port = serial.Serial(device, 9600, timeout=0)
            self.btn_open.setEnabled(False)
            self.btn_close.setEnabled(True)
            self.btn_refresh.setEnabled(False)
            self.btn_send.setEnabled(True)
            self.status.showMessage(f"Opened {device}")
        except serial.SerialException as e:
            self.status.showMessage(f"Error: {e}")

    def _close_port(self):
        if self.serial_port:
            self.serial_port.close()
            self.serial_port = None
        self.btn_open.setEnabled(True)
        self.btn_close.setEnabled(False)
        self.btn_refresh.setEnabled(True)
        self.btn_send.setEnabled(False)
        self.btn_panel.resetAll()
        self.status.showMessage("Port closed.")

    def _send_text(self):
        text = self.text_input.text().strip()
        if not text or not self.serial_port:
            return
        try:
            self.serial_port.write(f"0,{text}\n".encode())
            self.status.showMessage(f"Sent: {text}")
            self.text_input.clear()
        except serial.SerialException as e:
            self.status.showMessage(f"Write error: {e}")

    def _poll_serial(self):
        if not self.serial_port:
            return
        try:
            if self.serial_port.in_waiting:
                raw = self.serial_port.read(self.serial_port.in_waiting)
                self._read_buffer += raw.decode(errors="replace")
                while "\n" in self._read_buffer:
                    line, self._read_buffer = self._read_buffer.split("\n", 1)
                    self._parse_line(line.strip())
        except serial.SerialException:
            self._close_port()
            self.status.showMessage("Device disconnected.")

    def _parse_line(self, line: str):
        """Parse '1,<index>,<0|1>' button state messages."""
        parts = line.split(",")
        if len(parts) >= 3 and parts[0] == "1":
            try:
                idx   = int(parts[1])
                state = int(parts[2]) == 1
                self.btn_panel.setState(idx, state)
            except ValueError:
                pass

    def closeEvent(self, event):
        if self.serial_port:
            self.serial_port.close()
        event.accept()


# ── Entry point ───────────────────────────────────────────────────────────────

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(app.exec())