"""
File: utils.py
Author: Dmitry Ryumin, Maxim Markitantov, Elena Ryumina, Anastasia Dvoynikova, and Alexey Karpov
Description: Utility functions.
License: MIT License
"""

import time
import torch
import os
import subprocess
import bisect
import re
import requests
from torchvision import transforms
from PIL import Image
from transformers import WhisperProcessor, WhisperForConditionalGeneration
from pathlib import Path
from contextlib import suppress
from urllib.parse import urlparse
from contextlib import ContextDecorator

from typing import Callable


class Timer(ContextDecorator):
    """Context manager for measuring code execution time"""

    def __enter__(self):
        self.start = time.time()
        return self

    def __exit__(self, *args):
        self.end = time.time()
        self.execution_time = f"{self.end - self.start:.2f} seconds"

    def __str__(self):
        return self.execution_time


def load_model(
    model_url: str, folder_path: str, force_reload: bool = False
) -> str | None:

    file_name = Path(urlparse(model_url).path).name
    file_path = Path(folder_path) / file_name

    if file_path.exists() and not force_reload:
        return str(file_path)

    with suppress(Exception), requests.get(model_url, stream=True) as response:
        file_path.parent.mkdir(parents=True, exist_ok=True)

        with file_path.open("wb") as file:
            for chunk in response.iter_content(chunk_size=8192):
                file.write(chunk)

        return str(file_path)

    return None


def readetect_speech(
    file_path: str,
    read_audio: Callable,
    get_speech_timestamps: Callable,
    vad_model: torch.jit.ScriptModule,
    sr: int = 16000,
) -> list[dict]:
    wav = read_audio(file_path, sampling_rate=sr)
    # get speech timestamps from full audio file
    speech_timestamps = get_speech_timestamps(wav, vad_model, sampling_rate=sr)

    return wav, speech_timestamps


def calculate_mode(series):
    mode = series.mode()
    return mode[0] if not mode.empty else None


def pth_processing(fp):
    class PreprocessInput(torch.nn.Module):
        def init(self):
            super(PreprocessInput, self).init()

        def forward(self, x):
            x = x.to(torch.float32)
            x = torch.flip(x, dims=(0,))
            x[0, :, :] -= 91.4953
            x[1, :, :] -= 103.8827
            x[2, :, :] -= 131.0912
            return x

    def get_img_torch(img, target_size=(224, 224)):
        transform = transforms.Compose([transforms.PILToTensor(), PreprocessInput()])
        img = img.resize(target_size, Image.Resampling.NEAREST)
        img = transform(img)
        img = torch.unsqueeze(img, 0)
        return img

    return get_img_torch(fp)


def get_idx_frames_in_windows(
    frames: list[int], window: dict, fps: int, sr: int = 16000
) -> list[list]:

    frames_in_windows = [
        idx
        for idx, frame in enumerate(frames)
        if window["start"] * fps / sr <= frame < window["end"] * fps / sr
    ]
    return frames_in_windows


# Maxim code
def slice_audio(
    start_time: float,
    end_time: float,
    win_max_length: float,
    win_shift: float,
    win_min_length: float,
) -> list[dict]:
    """Slices audio on windows

    Args:
        start_time (float): Start time of audio
        end_time (float): End time of audio
        win_max_length (float): Window max length
        win_shift (float): Window shift
        win_min_length (float): Window min length

    Returns:
        list[dict]: List of dict with timings, f.e.: {'start': 0, 'end': 12}
    """

    if end_time < start_time:
        return []
    elif (end_time - start_time) > win_max_length:
        timings = []
        while start_time < end_time:
            end_time_chunk = start_time + win_max_length
            if end_time_chunk < end_time:
                timings.append({"start": start_time, "end": end_time_chunk})
            elif end_time_chunk == end_time:  # if tail exact `win_max_length` seconds
                timings.append({"start": start_time, "end": end_time_chunk})
                break
            else:  # if tail less then `win_max_length` seconds
                if (
                    end_time - start_time < win_min_length
                ):  # if tail less then `win_min_length` seconds
                    break

                timings.append({"start": start_time, "end": end_time})
                break

            start_time += win_shift
        return timings
    else:
        return [{"start": start_time, "end": end_time}]


def convert_video_to_audio(file_path: str, sr: int = 16000) -> str:
    path_save = file_path.split(".")[0] + ".wav"
    if not os.path.exists(path_save):
        ffmpeg_command = f"ffmpeg -y -i {file_path} -async 1 -vn -acodec pcm_s16le -ar {sr} {path_save}"
        subprocess.call(ffmpeg_command, shell=True)

    return path_save


def find_nearest_frames(target_frames, all_frames):
    nearest_frames = []
    for frame in target_frames:
        pos = bisect.bisect_left(all_frames, frame)
        if pos == 0:
            nearest_frame = all_frames[0]
        elif pos == len(all_frames):
            nearest_frame = all_frames[-1]
        else:
            before = all_frames[pos - 1]
            after = all_frames[pos]
            nearest_frame = before if frame - before <= after - frame else after
        nearest_frames.append(nearest_frame)
    return nearest_frames


def find_intersections(
    x: list[dict], y: list[dict], min_length: float = 0
) -> list[dict]:
    """Find intersections of two lists of dicts with intervals, preserving structure of `x` and adding intersection info

    Args:
        x (list[dict]): First list of intervals
        y (list[dict]): Second list of intervals
        min_length (float, optional): Minimum length of intersection. Defaults to 0.

    Returns:
        list[dict]: Windows with intersections, maintaining structure of `x`, and indicating intersection presence.
    """
    timings = []
    j = 0

    for interval_x in x:
        original_start = int(interval_x["start"])
        original_end = int(interval_x["end"])
        intersections_found = False

        while j < len(y) and y[j]["end"] < original_start:
            j += 1  # Skip any intervals in `y` that end before the current interval in `x` starts

        # Check for all overlapping intervals in `y`
        temp_j = (
            j  # Temporary pointer to check intersections within `y` for current `x`
        )
        while temp_j < len(y) and y[temp_j]["start"] <= original_end:
            # Calculate the intersection between `x[i]` and `y[j]`
            intersection_start = max(original_start, y[temp_j]["start"])
            intersection_end = min(original_end, y[temp_j]["end"])

            if (
                intersection_start < intersection_end
                and (intersection_end - intersection_start) >= min_length
            ):
                timings.append(
                    {
                        "original_start": original_start,
                        "original_end": original_end,
                        "start": intersection_start,
                        "end": intersection_end,
                        "speech": True,
                    }
                )
                intersections_found = True

            temp_j += 1  # Move to the next interval in `y` for further intersections

        # If no intersections were found, add the interval with `intersected` set to False
        if not intersections_found:
            timings.append(
                {
                    "original_start": original_start,
                    "original_end": original_end,
                    "start": None,
                    "end": None,
                    "speech": False,
                }
            )

    return timings


# Anastasia code
class ASRModel:
    def __init__(self, checkpoint_path: str, device: torch.device):
        self.processor = WhisperProcessor.from_pretrained(checkpoint_path)
        self.model = WhisperForConditionalGeneration.from_pretrained(
            checkpoint_path
        ).to(device)
        self.device = device
        self.model.config.forced_decoder_ids = None

    def __call__(
        self, sample: torch.Tensor, audio_windows: dict, sr: int = 16000
    ) -> tuple:
        texts = []

        for t in range(len(audio_windows)):
            input_features = self.processor(
                sample[audio_windows[t]["start"] : audio_windows[t]["end"]],
                sampling_rate=sr,
                return_tensors="pt",
            ).input_features
            predicted_ids = self.model.generate(input_features.to(self.device))
            transcription = self.processor.batch_decode(
                predicted_ids, skip_special_tokens=False
            )
            curr_text = re.findall(r"> ([^<>]+)", transcription[0])
            if curr_text:
                texts.append(curr_text)
            else:
                texts.appemd("")

        # for drawing
        input_features = self.processor(
            sample, sampling_rate=sr, return_tensors="pt"
        ).input_features
        predicted_ids = self.model.generate(input_features.to(self.device))
        transcription = self.processor.batch_decode(
            predicted_ids, skip_special_tokens=False
        )
        total_text = re.findall(r"> ([^<>]+)", transcription[0])

        return texts, total_text


def convert_webm_to_mp4(input_file):

    path_save = input_file.split(".")[0] + ".mp4"

    if not os.path.exists(path_save):
        ff_video = "ffmpeg -i {} -c:v copy -c:a aac -strict experimental {}".format(
            input_file, path_save
        )
        subprocess.call(ff_video, shell=True)

    return path_save