# Copyright (c) Facebook, Inc. and its affiliates.
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.

import logging
import os
import sys

import numpy as np
from sklearn.cluster import MiniBatchKMeans
from tqdm import tqdm

import joblib

logging.basicConfig(
    format="%(asctime)s | %(levelname)s | %(name)s | %(message)s",
    datefmt="%Y-%m-%d %H:%M:%S",
    level=os.environ.get("LOGLEVEL", "INFO").upper(),
    stream=sys.stdout,
)
logger = logging.getLogger("learn_kmeans")


def get_km_model(
    n_clusters,
    init,
    max_iter,
    batch_size,
    tol,
    max_no_improvement,
    n_init,
    reassignment_ratio,
):
    return MiniBatchKMeans(
        n_clusters=n_clusters,
        init=init,
        max_iter=max_iter,
        batch_size=batch_size,
        verbose=1,
        compute_labels=False,
        tol=tol,
        max_no_improvement=max_no_improvement,
        init_size=None,
        n_init=n_init,
        reassignment_ratio=reassignment_ratio,
    )


def load_feature(feat_path, leng_path, percent):
    with open(leng_path, "r") as f:
        lengs = [int(line.rstrip()) for line in f]
        offsets = [0] + np.cumsum(lengs[:-1]).tolist()

    if percent <= 0:
        print(f"{len(feat)} frames ")
        return np.load(feat_path, mmap_mode="r")
    else:
        nsample = int(np.ceil(len(lengs) * percent))
        indices = np.random.choice(len(lengs), nsample, replace=False)
        print(len(lengs), nsample, len(indices))
        feat = np.load(feat_path, mmap_mode="r")
        sampled_feat = np.concatenate(
            [feat[offsets[i]: offsets[i] + lengs[i]] for i in tqdm(indices)], axis=0
        )
        print(f"sampled {nsample} utterances, {len(sampled_feat)} frames ")
        logger.info(
            (
                f"sampled {nsample} utterances, {len(sampled_feat)} frames "
            )
        )
        return sampled_feat


#def load_feature(feat_path, leng_path, percent):
#    assert percent <= 1.0
#    feat = np.concatenate(
#        [
#            load_feature_shard(feat_path, leng_path, percent)
#            for r in range(nshard)
#        ],
#        axis=0,
#    )
#    logging.info(f"loaded feature with dimension {feat.shape}")
#    return feat


def learn_kmeans(
    feat_path,
    leng_path,
    km_path,
    n_clusters,
    seed,
    percent,
    init,
    max_iter,
    batch_size,
    tol,
    n_init,
    reassignment_ratio,
    max_no_improvement,
):
    np.random.seed(seed)
    feat = load_feature(feat_path, leng_path, percent)
    km_model = get_km_model(
        n_clusters,
        init,
        max_iter,
        batch_size,
        tol,
        max_no_improvement,
        n_init,
        reassignment_ratio,
    )
    km_model.fit(feat)
    joblib.dump(km_model, km_path)

    inertia = -km_model.score(feat) / len(feat)
    logger.info("total intertia: %.5f", inertia)
    logger.info("finished successfully")


if __name__ == "__main__":
    import argparse

    parser = argparse.ArgumentParser()
    parser.add_argument("feat_path", type=str)
    parser.add_argument("leng_path", type=str)
    parser.add_argument("km_path", type=str)
    parser.add_argument("n_clusters", type=int)
    parser.add_argument("--seed", default=0, type=int)
    parser.add_argument(
        "--percent", default=-1, type=float, help="sample a subset; -1 for all"
    )
    parser.add_argument("--init", default="k-means++")
    parser.add_argument("--max_iter", default=100, type=int)
    parser.add_argument("--batch_size", default=10000, type=int)
    parser.add_argument("--tol", default=0.0, type=float)
    parser.add_argument("--max_no_improvement", default=100, type=int)
    parser.add_argument("--n_init", default=20, type=int)
    parser.add_argument("--reassignment_ratio", default=0.0, type=float)
    args = parser.parse_args()
    logging.info(str(args))

    learn_kmeans(**vars(args))