import os
import time
import hashlib
import datetime
import torch
import torch.nn as nn
import logging
import numpy as np
import pandas as pd
from matplotlib import pyplot as plt
from tqdm import tqdm
plt.rcParams["figure.dpi"] = 288 # increase dpi for clearer plots

from plotting import * # mostly for debug

from sklearn.metrics import roc_auc_score, precision_recall_curve, f1_score, auc


# PARAMS =======================
INPUT_SIZE = (96, 256)
MAX_FRAMES = 40


# CONFIG =======================

# paths:
hostname = os.uname()[1]
if hostname in ['rechenknecht0.cp.jku.at', 'rechenknecht1.cp.jku.at', 'rechenknecht3.cp.jku.at']:
    plt.switch_backend('agg')
    PATH_DATA_ROOT = '/home/shreyan/data/MTG-Jamendo'
    USE_GPU = True
elif hostname == 'hermine':  # PC verena
    plt.switch_backend('agg')
    PATH_DATA_ROOT = '/media/verena/SAMSUNG/Data/MTG-Jamendo'
    USE_GPU = True
else:
    PATH_DATA_ROOT = '/mnt/2tb/datasets/MTG-Jamendo'
    USE_GPU = False

PATH_PROJECT_ROOT = os.path.dirname(os.path.realpath(__file__))
PATH_AUDIO = os.path.join(PATH_DATA_ROOT, 'MTG-Jamendo_audio')
PATH_ANNOTATIONS = os.path.join(PATH_DATA_ROOT, 'MTG-Jamendo_annotations')
PATH_MELSPEC_DOWNLOADED = os.path.join(PATH_DATA_ROOT, 'MTG-Jamendo_melspec_downloaded')
PATH_MELSPEC_DOWNLOADED_FRAMED = os.path.join(PATH_MELSPEC_DOWNLOADED, 'framed')
PATH_RESULTS = os.path.join(PATH_PROJECT_ROOT, 'results')
TRAINED_MODELS_PATH = ''

# run name
def make_run_name(suffix=''):
    assert ' ' not in suffix
    hash = hashlib.sha1()
    hash.update(str(time.time()).encode('utf-8'))
    run_hash = hash.hexdigest()[:5]
    name = run_hash + suffix
    return name

curr_run_name = make_run_name()
CURR_RUN_PATH = os.path.join(PATH_RESULTS, 'runs', curr_run_name)

if not os.path.isdir(CURR_RUN_PATH):
    os.mkdir(CURR_RUN_PATH)

# SET UP LOGGING =============================================
filelog = logging.getLogger()
streamlog = logging.getLogger()
logger = logging.getLogger()
fh = logging.FileHandler(os.path.join(CURR_RUN_PATH, f'{curr_run_name}.log'))
sh = logging.StreamHandler()
formatter = logging.Formatter('%(asctime)s\t%(name)s\t%(levelname)s\t%(message)s')
fh.setFormatter(formatter)
sh.setFormatter(formatter)

# filelog logs only to file
filelog.addHandler(fh)
filelog.setLevel(logging.INFO)

# streamlog logs only to terminal
streamlog.addHandler(sh)
streamlog.setLevel(logging.INFO)

# logger logs to both file and terminal
logger.addHandler(fh)
logger.addHandler(sh)
logger.setLevel(logging.DEBUG)

# ============================================

def write_to_file(data, path):
    # not fully implemented. unused function as of now.
    with open(path, 'w') as f:
        if isinstance(data, np.ndarray):
            for i in data:
                f.writelines(i)


def dims_calc(obj, in_shape):
    """
    utility function to calculate output dimensions of a conv2d or maxpool2d stage
    """
    kernel_size = obj.kernel_size
    stride = obj.stride
    padding = obj.padding
    dilation = obj.dilation
    h_in = in_shape[0]
    w_in = in_shape[1]

    if isinstance(obj, nn.Conv2d):
        h_out = int(((h_in + 2*padding[0] - dilation[0]*(kernel_size[0]-1))/stride[0])+1)
        w_out = int(((w_in + 2*padding[1] - dilation[1]*(kernel_size[1]-1))/stride[1])+1)
        out_shape = [h_out, w_out, obj.out_channels]
    elif isinstance(obj, nn.MaxPool2d):
        if isinstance(padding, int):
            padding = (padding, padding)
        if isinstance(dilation, int):
            dilation = (dilation, dilation)
        if isinstance(kernel_size, int):
            kernel_size = (kernel_size, kernel_size)
        if isinstance(stride, int):
            stride = (stride, stride)

        h_out = int(((h_in + 2 * padding[0] - dilation[0] * (kernel_size[0] - 1) -1) / stride[0]) + 1)
        w_out = int(((w_in + 2 * padding[1] - dilation[1] * (kernel_size[1] - 1)-1) / stride[1]) + 1)
        out_shape = [h_out, w_out, in_shape[2]]
    else:
        out_shape = [None, None, None]
    return out_shape

def preprocess_and_save_annotation_files():
    """
    Removes 'mood/theme---' from tag names, and replaces tabs between multiple tag names with commas.
    Writes processed filename.ext as filename_processed.ext
    """
    import re
    filelist = os.listdir(PATH_ANNOTATIONS)
    for file in filelist:
        # Check if the current file is processed or has a processed copy.
        # Skip if either of this is true. Else process.
        if 'processed' in os.path.splitext(file)[0].split('_') or\
            f'{os.path.splitext(file)[0]}_processed{os.path.splitext(file)[1]}' in filelist:
            continue
        else:
            with open(os.path.join(PATH_ANNOTATIONS, file), 'r') as f:
                text = f.read()
            text = re.sub(r'mood/theme---(\w*)\n', r'\1\n', text) # matches last or singular tags
            text = re.sub(r'mood/theme---(\w*)(\s*)', r'\1,', text) # matches all other tags

            with open(os.path.join(PATH_ANNOTATIONS,
                                   f'{os.path.splitext(file)[0]}_processed{os.path.splitext(file)[1]}'), 'w') as fw:
                fw.write(text)


def trim_silence(spec, thresh=0.1):
    """
    Trims silence from the beginning and end of a song spectrogram based on a threshold
    applied to the median loudness. Loudness is calculated by summing the magnitudes
    over the frequency axis for each time frame.
    """
    loudness = np.sum(spec, axis=0)
    loudness = loudness - np.min(loudness)
    cutoff = thresh*np.median(loudness)
    start = 0
    end = len(loudness)
    for i in range(len(loudness)):
        if loudness[i] > cutoff:
            start = i
            break
    for i in range(len(loudness)-1, start, -1):
        if loudness[i] > cutoff:
            end = i
            break
    return spec[:,start:end]


def make_framed_spec(spec, frame_length, total_frames=None,
                hop=0.5, discard_end=False, filler='wrap'):
    """
    Given a spectrogram of an entire song, this function splits it into frames and returns
    a torch tensor with an additional dimension (frame number) and the framed spectrogram
    chunks. Each frame is meant to be directly fed into a model input of matching size.
    """
    assert filler in ['wrap', 'pad'], logger.error(f"filler is {filler}, must be either wrap or pad")
    fstart = 0
    fend = int(frame_length)
    framed_spec = []

    while fend < spec.shape[1]:
        framed_spec.append(spec[:,fstart:fend])
        fstart += int(hop*frame_length)
        fend = fstart + int(frame_length)
    if not discard_end:
        framed_spec.append(spec[:,-frame_length:])

    if total_frames is not None:
        if len(framed_spec) > total_frames:
            framed_spec = framed_spec[:total_frames]
        else:
            if filler in ['wrap']:
                # Wrap around
                while len(framed_spec) < total_frames:
                    framed_spec.extend(framed_spec[0:total_frames-len(framed_spec)])
            else:
                # Pad with silence
                silence = np.zeros(spec[:,0:frame_length].shape)
                while len(framed_spec) < total_frames:
                    framed_spec.extend(silence)

    framed_spec = torch.from_numpy(np.array(framed_spec))
    return framed_spec


def preprocess_specs(source_root, destination_root, frame_length=256, hop=1.0):
    """
    Reads spectrograms from source_root and performs:
        - trim_silence()
        - make_framed_spec()
    and saves the resulting framed spectrograms to destination_root
    """
    if not os.path.exists(destination_root):
        os.mkdir(destination_root)

    filelist = os.walk(source_root)

    for dirpath, _, filenames in filelist:
        # Ignore dir of framed specs
        if dirpath is destination_root:
            continue

        for filename in tqdm(filenames):
            destination_subdir = os.path.join(destination_root, dirpath.split('/')[-1])
            if os.path.exists(os.path.join(destination_subdir, filename)):
                # If framed melspec already exists, don't preprocess
                continue
            else:
                if not os.path.exists(destination_subdir):
                    os.mkdir(destination_subdir)
                destination = os.path.join(destination_subdir, filename)
                spec = np.load(os.path.join(dirpath, filename))
                spec = trim_silence(spec)
                framed_spec = make_framed_spec(spec, frame_length=frame_length, hop=hop)
                np.save(destination, framed_spec)


if __name__=='__main__':
    # TESTS

    # c = nn.Conv2d(512, 256, 1, 1, 0) # (in_channels, out_channels, kernel_size, stride, padding)
    # m = nn.MaxPool2d(2)
    # print(dims_calc(c, [37, 17, 512]))
    preprocess_specs(source_root=PATH_MELSPEC_DOWNLOADED,
                     destination_root=PATH_MELSPEC_DOWNLOADED_FRAMED)
    pass