# =============================================================================
# st7789_driver.py — ST7789V(240x320) SPI 드라이버 (GMT020-02 등)
#   외부 디스플레이 라이브러리 의존 없음(폐쇄망 최소 의존):
#   spidev + RPi.GPIO + numpy(RGB565 변환) + Pillow(Image 입력)만 사용.
#   하드웨어/모듈 부재 시 SimulationDisplay 로 폴백(PNG 저장) — sht30 드라이버와 동일 철학.
# =============================================================================
import time

try:
    import numpy as np
except ImportError:      # numpy 없으면 순수 파이썬 변환(느리지만 동작)
    np = None


class SimulationDisplay:
    """SPI/GPIO 불가 환경 폴백 — 프레임을 PNG 로 저장해 렌더 결과를 검증한다."""

    def __init__(self, width=240, height=320, preview_path="/tmp/display_preview.png"):
        self.width, self.height = width, height
        self.preview_path = preview_path

    def display(self, image):
        image.save(self.preview_path)

    def set_backlight(self, on):
        pass

    def close(self):
        pass


class ST7789:
    """ST7789V 240x320 — 초기화·전체 프레임 블릿. 부분 갱신은 쓰지 않는다(30초 주기)."""

    def __init__(self, spi_bus=0, spi_device=0, speed_hz=40_000_000,
                 dc=25, rst=24, bl=None, width=240, height=320,
                 rotation=0, invert=True):
        import spidev
        import RPi.GPIO as GPIO
        self.GPIO = GPIO
        self.width, self.height = width, height
        self.rotation = rotation
        self.dc, self.rst, self.bl = dc, rst, bl

        GPIO.setwarnings(False)
        GPIO.setmode(GPIO.BCM)
        GPIO.setup(dc, GPIO.OUT)
        GPIO.setup(rst, GPIO.OUT)
        if bl is not None:               # 7핀 모듈(BLK 없음)은 백라이트 제어 생략
            GPIO.setup(bl, GPIO.OUT)

        self.spi = spidev.SpiDev()
        self.spi.open(spi_bus, spi_device)
        self.spi.max_speed_hz = speed_hz
        self.spi.mode = 0

        self._reset()
        self._init_panel(invert)
        self.set_backlight(True)

    # ── 저수준 ──────────────────────────────────────────────
    def _cmd(self, cmd, data=None):
        self.GPIO.output(self.dc, 0)
        self.spi.writebytes([cmd])
        if data:
            self.GPIO.output(self.dc, 1)
            self.spi.writebytes(list(data))

    def _reset(self):
        self.GPIO.output(self.rst, 1); time.sleep(0.05)
        self.GPIO.output(self.rst, 0); time.sleep(0.05)
        self.GPIO.output(self.rst, 1); time.sleep(0.15)

    def _init_panel(self, invert):
        self._cmd(0x01); time.sleep(0.15)            # SWRESET
        self._cmd(0x11); time.sleep(0.12)            # SLPOUT
        self._cmd(0x3A, [0x55])                      # COLMOD: 16bit RGB565
        self._cmd(0x36, [self._madctl()])            # MADCTL: 회전
        self._cmd(0xB2, [0x0C, 0x0C, 0x00, 0x33, 0x33])   # PORCTRL
        self._cmd(0xB7, [0x35])                      # GCTRL
        self._cmd(0xBB, [0x19])                      # VCOMS
        self._cmd(0xC0, [0x2C])                      # LCMCTRL
        self._cmd(0xC2, [0x01])                      # VDVVRHEN
        self._cmd(0xC3, [0x12])                      # VRHS
        self._cmd(0xC4, [0x20])                      # VDVS
        self._cmd(0xC6, [0x0F])                      # FRCTRL2 60Hz
        self._cmd(0xD0, [0xA4, 0xA1])                # PWCTRL1
        self._cmd(0xE0, [0xD0, 0x04, 0x0D, 0x11, 0x13, 0x2B,   # PVGAMCTRL
                         0x3F, 0x54, 0x4C, 0x18, 0x0D, 0x0B, 0x1F, 0x23])
        self._cmd(0xE1, [0xD0, 0x04, 0x0C, 0x11, 0x13, 0x2C,   # NVGAMCTRL
                         0x3F, 0x44, 0x51, 0x2F, 0x1F, 0x1F, 0x20, 0x23])
        self._cmd(0x21 if invert else 0x20)          # INVON/INVOFF
        self._cmd(0x13)                              # NORON
        self._cmd(0x29); time.sleep(0.05)            # DISPON

    def _madctl(self):
        return {0: 0x00, 90: 0x60, 180: 0xC0, 270: 0xA0}.get(self.rotation, 0x00)

    def _set_window(self):
        w, h = (self.width, self.height) if self.rotation in (0, 180) else (self.height, self.width)
        self._cmd(0x2A, [0, 0, (w - 1) >> 8, (w - 1) & 0xFF])   # CASET
        self._cmd(0x2B, [0, 0, (h - 1) >> 8, (h - 1) & 0xFF])   # RASET
        self._cmd(0x2C)                                          # RAMWR

    # ── 공개 API ────────────────────────────────────────────
    def display(self, image):
        """PIL RGB 이미지를 전체 프레임으로 전송."""
        w, h = (self.width, self.height) if self.rotation in (0, 180) else (self.height, self.width)
        if image.size != (w, h):
            image = image.resize((w, h))
        if np is not None:
            arr = np.asarray(image.convert("RGB"), dtype=np.uint16)
            rgb565 = ((arr[..., 0] & 0xF8) << 8) | ((arr[..., 1] & 0xFC) << 3) | (arr[..., 2] >> 3)
            buf = rgb565.byteswap().tobytes()       # 빅엔디안
        else:
            px = image.convert("RGB").load()
            buf = bytearray(w * h * 2)
            i = 0
            for y in range(h):
                for x in range(w):
                    r, g, b = px[x, y]
                    v = ((r & 0xF8) << 8) | ((g & 0xFC) << 3) | (b >> 3)
                    buf[i] = v >> 8; buf[i + 1] = v & 0xFF
                    i += 2
        self._set_window()
        self.GPIO.output(self.dc, 1)
        if hasattr(self.spi, "writebytes2"):        # 버퍼 직접 전송(자동 분할)
            self.spi.writebytes2(buf)
        else:                                        # 구버전 spidev 폴백: list 로 분할 전송
            for ofs in range(0, len(buf), 4096):
                self.spi.writebytes(list(buf[ofs:ofs + 4096]))

    def set_backlight(self, on):
        if self.bl is not None:
            self.GPIO.output(self.bl, 1 if on else 0)

    def close(self):
        try:
            self.set_backlight(False)
            self.spi.close()
        except Exception:
            pass


def open_display(cfg):
    """설정 기반 디스플레이 오픈 — 하드웨어 불가 시 시뮬레이션 폴백."""
    if getattr(cfg, "FORCE_SIMULATION", False):
        return SimulationDisplay(cfg.WIDTH, cfg.HEIGHT), True
    try:
        disp = ST7789(
            spi_bus=cfg.SPI_BUS, spi_device=cfg.SPI_DEVICE, speed_hz=cfg.SPI_SPEED_HZ,
            dc=cfg.PIN_DC, rst=cfg.PIN_RST, bl=cfg.PIN_BL,
            width=cfg.WIDTH, height=cfg.HEIGHT,
            rotation=cfg.ROTATION, invert=cfg.INVERT,
        )
        return disp, False
    except Exception as e:
        print(f"[WARN] ST7789 init failed ({e}) — simulation fallback")
        return SimulationDisplay(cfg.WIDTH, cfg.HEIGHT), True