"""
Automated Photogrammetry Capture Suite
=====================================
This module automates a 360-degree photography sequence using an Olympus OM-D
EM-10 Mk III camera and an Arduino-controlled rotation stand.

The script synchronizes the two systems by:
1. Initializing the camera's internal API to enter shutter mode.
2. Establishing a persistent serial connection with the Arduino controller to
   manage rotation speed and movement.
3. Executing a sequenced loop of image capture, delay cycles, and incremental
   rotation steps.

Hardware Requirements:
-----------------------
- Camera: Olympus OM-D EM-10 Mk III (connected via its internal WiFi network).
- Stand: Arduino-based rotation table (connected via USB/Serial).

Usage Note:
----------
Ensure the Camera's WiFi is active and the script 'CAMERA_IP' matches its
assigned address on your network. Ensure the correct 'ARDUINO_PORT' is mapped
to your local system (e.g., /dev/ttyUSB0 or COMx).
"""

import requests
import serial
import time

# ================= CONFIGURATION =================
CAMERA_IP = "192.168.0.10"
ARDUINO_PORT = "/dev/ttyUSB0"
BAUD_RATE = 9600

# Motion Control
ROTATION_SPEED_DPS = 45.0
ROTATION_STEP_SIZE = 15.0
TOTAL_TARGET_DEGREES = 360.0

# Timing
PHOTO_TO_MOVE_DELAY = 8.0
TIMEOUT = 10.0
# ================================================


class SerialTimeoutError(Exception):
    pass


def initialize_camera():
    """
    Configures the camera's hardware state for photography.
    """
    print("[CAMERA] Switching to SHUTTER mode.")
    requests.get(
        f"http://{CAMERA_IP}/switch_cammode.cgi?mode=shutter", timeout=TIMEOUT
    )
    time.sleep(0.3)


def initialize_stand(ser):
    """
    Configures the Arduino-controlled rotation stand's parameters.

    This is a blocking function. It sends commands to set the stand into
    MANUAL mode and defines the rotation speed (deg/sec). It will not return
    until the Arduino confirms these states have been successfully accepted.

    Args:
        ser (serial.Serial): The open serial connection to the Arduino controller.
    """
    print("[STAND] Switching to MANUAL mode.")
    ser.write(f"m1\n".encode())
    time.sleep(0.3)
    await_completion(ser, "Mode: MANUAL")

    print(
        f"[STAND] Setting rotation speed to {ROTATION_SPEED_DPS} degrees/second."
    )
    ser.write(f"s{ROTATION_SPEED_DPS}\n".encode())
    time.sleep(0.3)
    await_completion(ser, f"Speed: {ROTATION_SPEED_DPS:.0f}")


def take_photo():
    """
    Triggers the camera's shutter and waits for capture completion.
    """
    print("[CAMERA] Activating electronic shutter.")
    requests.get(
        f"http://{CAMERA_IP}/exec_shutter.cgi?type=1st2ndpush", timeout=TIMEOUT
    )
    time.sleep(0.3)

    requests.get(
        f"http://{CAMERA_IP}/exec_shutter.cgi?com=2nd1strelease",
        timeout=TIMEOUT,
    )
    time.sleep(PHOTO_TO_MOVE_DELAY)  # Buffer to account for shutter speed


def rotate_stand(ser):
    """
    Commands the stand to perform a specific rotation.

    This is a blocking function. It sends the degrees-to-rotate command
    and monitors the serial line until the Arduino confirms that the
    movement has finished or is ready for the next instruction.

    Args:
        ser (serial.Serial): The open serial connection to the Arduino controller.
    """
    print(f"[STAND] Rotating stand by {ROTATION_STEP_SIZE} degrees.")
    ser.write(f"a{ROTATION_STEP_SIZE}\n".encode())
    time.sleep(0.3)
    await_completion(ser, "Waiting")


def await_completion(ser, s):
    """
    Blocks the execution of the script until a specific confirmation
    string is detected in the serial output from the Arduino.

    Args:
        ser (serial.Serial): The open serial connection to the Arduino.
        s (str): The substring expected in the response to indicate completion.

    Raises:
        SerialTimeoutError: If no data is received or if a
                            non-matching line is found repeatedly.
    """
    while True:
        line_bytes = ser.readline()
        line_str = line_bytes.decode("utf-8").strip()

        if not line_str:
            raise SerialTimeoutError

        if s in line_str:
            break

        time.sleep(0.1)


def main():
    with serial.Serial(ARDUINO_PORT, BAUD_RATE, timeout=TIMEOUT) as ser:
        try:
            time.sleep(2.0)  # Buffer to account for Arduino startup

            print("Flushing serial buffers.")
            ser.reset_input_buffer()
            ser.reset_output_buffer()

            initialize_stand(ser)
            initialize_camera()
            time.sleep(2.0)  # Buffer to ensure the display is not moving

            current_angle = 0.0

            while current_angle < TOTAL_TARGET_DEGREES:
                take_photo()
                rotate_stand(ser)

                current_angle += ROTATION_STEP_SIZE

        except requests.Timeout:
            print("Connection to camera API lost.")

        except SerialTimeoutError:
            print("Arduino failed to respond in time.")


if __name__ == "__main__":
    main()


# Send `m1` command
# Response: "Mode: MANUAL | State: WAIT | Steps Left: 0 | Speed: 45.00 deg/s | Wait: 8.00s"

# Send `s45` command
# Response: "Mode: MANUAL | State: WAIT | Steps Left: 0 | Speed: 45.00 deg/s | Wait: 8.00s"

# Send `a15` command
# Response: "Waiting indefinitely for new command (MANUAL mode)."