"""Single-threaded finger acquisition API, independent of UART and the CLI.

Sensor IDs are 1-based, fixed by source order. Calls and runtime ownership belong
to one thread; the caller must close the bank in a finally block. Values use the
SDK's FNORMAL/FSHEARX/FSHEARY axes and calibration units, not assumed Newtons.
"""

from __future__ import annotations

import logging
import math
from dataclasses import dataclass
from pathlib import Path

Source = int | str
logger = logging.getLogger(__name__)


def parse_source(token: str) -> Source:
    text = token.strip()
    if not text:
        raise ValueError("empty source")
    return int(text) if text.isdigit() or (text.startswith("-") and text[1:].isdigit()) else text


def is_video_file(source: Source) -> bool:
    from orisys.capture import is_live_camera

    return not is_live_camera(source) and not isinstance(source, int)


@dataclass(frozen=True)
class ForceReading:
    sensor_id: int
    normal: float
    shear_x: float
    shear_y: float
    units: tuple[str, str, str]
    image: object


class FingerSensorBank:
    """Own 1–4 independent runtimes. read() returns None at EOF/capture failure.

    Processing/connection failures raise exceptions; they never become zero force.
    A shared config can be reused, or each source can have its own config.
    """

    def __init__(self, sources=(0,), *, configs=("finger",), verbose=False):
        sources = tuple(parse_source(str(source)) for source in sources)
        configs = tuple(configs)
        if not 1 <= len(sources) <= 4:
            raise ValueError("provide 1 to 4 sources")
        if len(configs) not in (1, len(sources)):
            raise ValueError("provide one config or one config per source")
        if any(isinstance(source, int) and source < 0 for source in sources):
            raise ValueError("camera index must be non-negative")
        if len(configs) == 1:
            configs = configs * len(sources)
        self.sources = dict(enumerate(sources, 1))
        self.configs = dict(enumerate(configs, 1))
        self.runtimes = {}
        self.verbose = verbose

    def validate_id(self, sensor_id: int) -> None:
        if sensor_id not in self.sources:
            raise ValueError(f"sensor ID must be 1..{len(self.sources)}")

    def connect(self, sensor_id: int = 1, source: Source | None = None) -> Source:
        from orisys.finger import FingerRuntime

        self.validate_id(sensor_id)
        source = self.sources[sensor_id] if source is None else parse_source(str(source))
        if isinstance(source, int) and source < 0:
            raise ValueError("camera index must be non-negative")
        if is_video_file(source) and not Path(source).is_file():
            raise ValueError(f"file not found: {source}")
        if source in (self.sources[i] for i in self.runtimes if i != sensor_id):
            raise ValueError(f"source already connected: {source}")
        self.disconnect(sensor_id)
        runtime = FingerRuntime.open(
            config=self.configs[sensor_id], video=source, verbose=self.verbose,
        )
        try:
            ok, _ = runtime.warmup(color=False)
            if not ok:
                raise RuntimeError("warmup could not read a frame")
        except BaseException:
            runtime.close()
            raise
        self.runtimes[sensor_id] = runtime
        self.sources[sensor_id] = source
        return source

    def read(self, sensor_id: int = 1, *, loop_video=False) -> ForceReading | None:
        self.validate_id(sensor_id)
        if sensor_id not in self.runtimes:
            raise ValueError("not connected")
        runtime = self.runtimes[sensor_id]
        ok, image = runtime.grab_and_process(color=False)
        if not ok and loop_video and is_video_file(self.sources[sensor_id]):
            import cv2

            # One rewind attempt per read prevents an empty file from spinning forever.
            if runtime.capture is not None and runtime.capture.set(cv2.CAP_PROP_POS_FRAMES, 0):
                runtime.tactile.reset()
                ok, image = runtime.grab_and_process(color=False)
        if not ok:
            return None
        tactile = runtime.tactile
        tactile.compute_deformation()
        tactile.compute_contact()
        forces = tuple(float(value) for value in tactile.read_info(
            tactile.info.FNORMAL, tactile.info.FSHEARX, tactile.info.FSHEARY,
        ))
        if not all(math.isfinite(value) for value in forces):
            raise RuntimeError("non-finite force measurement")
        units = getattr(tactile, "force_units", ("unknown", "unknown", "unknown"))
        return ForceReading(sensor_id, *forces, tuple(units), image)

    def disconnect(self, sensor_id: int = 1) -> None:
        self.validate_id(sensor_id)
        runtime = self.runtimes.pop(sensor_id, None)
        if runtime is not None:
            runtime.close()

    def close(self) -> None:
        first_error = None
        for sensor_id in list(self.runtimes):
            try:
                self.disconnect(sensor_id)
            except Exception as exc:
                logger.exception("Sensor %s cleanup failed", sensor_id)
                first_error = first_error or exc
        if first_error is not None:
            raise first_error