import enum
import csv
import time

from PySide6.QtCore import QObject, Signal, QTimer


class ProfileState(enum.Enum):
    STOPPED = 0
    RUNNING = 1
    PAUSED = 2


class ProfileHandler(QObject):
    currentChanged = Signal(float)
    profileChanged = Signal(list)
    finished = Signal()

    state: ProfileState

    _timer: QTimer

    profile_start: float
    _profile: list[list[float]]
    _pause_time: float
    _last_current: float

    def __init__(self):
        super().__init__(parent=None)
        self.state = ProfileState.STOPPED
        self._timer = QTimer()
        self._timer.timeout.connect(self._update)
        self._timer.start(100)

        self._profile = []
        self.profile_start = 0
        self._pause_time = 0
        self._last_current = 0

    def load_profile(self, path: str):
        with open(path) as fh:
            result = []
            t = 0
            for l in csv.reader(fh):
                i = float(l[0])
                result.append([t, i])
                t += float(l[1])
                result.append([t, i])
            self._profile = result
            self.profileChanged.emit(result)
            return result

    def start(self):
        assert self.state == ProfileState.STOPPED

        self.profile_start = time.time()
        self.state = ProfileState.RUNNING
        current = self._profile[0][1]
        self._last_current = current
        self.currentChanged.emit(current)

    def pause(self):
        assert self.state == ProfileState.RUNNING

        self.state = ProfileState.PAUSED
        self.currentChanged.emit(0)
        self._last_current = 0
        self._pause_time = time.time()

    def resume(self):
        assert self.state == ProfileState.PAUSED

        dt = time.time() - self._pause_time
        self.profile_start += dt
        self.state = ProfileState.RUNNING

    def stop(self):
        assert self.state != ProfileState.STOPPED

        self.state = ProfileState.STOPPED
        self.currentChanged.emit(0)
        self._last_current = 0

    def _update(self):
        if self.state == ProfileState.RUNNING:
            dt = time.time() - self.profile_start
            try:
                current = next(t[1] for t in self._profile if t[0] >= dt)
                if current != self._last_current:
                    self.currentChanged.emit(current)
                    self._last_current = current
            except StopIteration:
                self.state = ProfileState.STOPPED
                self.finished.emit()
        else:
            self._last_current = 0
            self.currentChanged.emit(0)