import math
import os
import re
import tempfile
import logging
from dataclasses import dataclass

import torch
from torchaudio.models import wav2vec2_model

logger = logging.getLogger(__name__)

# iso codes with specialized rules in uroman
special_isos_uroman = "ara, bel, bul, deu, ell, eng, fas, grc, ell, eng, heb, kaz, kir, lav, lit, mkd, mkd2, oss, pnt, pus, rus, srp, srp2, tur, uig, ukr, yid".split(
    ","
)
special_isos_uroman = [i.strip() for i in special_isos_uroman]


def normalize_uroman(text):
    text = text.lower()
    text = re.sub("([^a-z' ])", " ", text)
    text = re.sub(" +", " ", text)
    return text.strip()


def get_uroman_tokens(norm_transcripts, uroman, iso=None):
    tf = tempfile.NamedTemporaryFile()
    tf2 = tempfile.NamedTemporaryFile()
    with open(tf.name, "w") as f:
        for t in norm_transcripts:
            f.write(t + "\n")
    uroman.romanize_file(
        input_filename=tf.name,
        output_filename=tf2.name,
        lcode=iso if iso in special_isos_uroman else None,
    )
    outtexts = []
    with open(tf2.name) as f:
        for line in f:
            line = " ".join(line.strip())
            line = re.sub(r"\s+", " ", line).strip()
            outtexts.append(line)
    assert len(outtexts) == len(norm_transcripts)
    uromans = []
    for ot in outtexts:
        uromans.append(normalize_uroman(ot))
    return uromans


@dataclass
class Segment:
    label: str
    start: int
    end: int

    def __repr__(self):
        return f"{self.label}: [{self.start:5d}, {self.end:5d})"

    @property
    def length(self):
        return self.end - self.start


def merge_repeats(path, idx_to_token_map):
    i1, i2 = 0, 0
    segments = []
    while i1 < len(path):
        while i2 < len(path) and path[i1] == path[i2]:
            i2 += 1
        segments.append(Segment(idx_to_token_map[path[i1]], i1, i2 - 1))
        i1 = i2
    return segments


def time_to_frame(time):
    stride_msec = 20
    frames_per_sec = 1000 / stride_msec
    return int(time * frames_per_sec)


def load_model_dict():
    # Use models directory from environment variable
    models_dir = os.environ.get("MODELS_DIR", "/home/user/app/models")
    model_path_name = os.path.join(models_dir, "ctc_alignment_mling_uroman_model.pt")

    logger.info("Loading model from models directory...")
    if not os.path.exists(model_path_name):
        raise FileNotFoundError(f"Model file not found at {model_path_name}")
    logger.info(f"Model found at: {model_path_name}")
    state_dict = torch.load(model_path_name, map_location="cpu")

    model = wav2vec2_model(
        extractor_mode="layer_norm",
        extractor_conv_layer_config=[
            (512, 10, 5),
            (512, 3, 2),
            (512, 3, 2),
            (512, 3, 2),
            (512, 3, 2),
            (512, 2, 2),
            (512, 2, 2),
        ],
        extractor_conv_bias=True,
        encoder_embed_dim=1024,
        encoder_projection_dropout=0.0,
        encoder_pos_conv_kernel=128,
        encoder_pos_conv_groups=16,
        encoder_num_layers=24,
        encoder_num_heads=16,
        encoder_attention_dropout=0.0,
        encoder_ff_interm_features=4096,
        encoder_ff_interm_dropout=0.1,
        encoder_dropout=0.0,
        encoder_layer_norm_first=True,
        encoder_layer_drop=0.1,
        aux_num_out=31,
    )
    model.load_state_dict(state_dict)
    model.eval()

    # Use models directory from environment variable
    models_dir = os.environ.get("MODELS_DIR", "/home/user/app/models")
    dict_path_name = os.path.join(
        models_dir, "ctc_alignment_mling_uroman_model_dict.txt"
    )
    if not os.path.exists(dict_path_name):
        raise FileNotFoundError(f"Dictionary file not found at {dict_path_name}")
    logger.info(f"Dictionary found at: {dict_path_name}")
    dictionary = {}
    with open(dict_path_name) as f:
        dictionary = {l.strip(): i for i, l in enumerate(f.readlines())}

    return model, dictionary


def get_spans(tokens, segments):
    ltr_idx = 0
    tokens_idx = 0
    intervals = []
    start, end = (0, 0)
    sil = "<blank>"
    for seg_idx, seg in enumerate(segments):
        if tokens_idx == len(tokens):
            assert seg_idx == len(segments) - 1
            assert seg.label == "<blank>"
            continue
        cur_token = tokens[tokens_idx].split(" ")
        ltr = cur_token[ltr_idx]
        if seg.label == "<blank>":
            continue
        assert seg.label == ltr
        if (ltr_idx) == 0:
            start = seg_idx
        if ltr_idx == len(cur_token) - 1:
            ltr_idx = 0
            tokens_idx += 1
            intervals.append((start, seg_idx))
            while tokens_idx < len(tokens) and len(tokens[tokens_idx]) == 0:
                intervals.append((seg_idx, seg_idx))
                tokens_idx += 1
        else:
            ltr_idx += 1
    spans = []
    for idx, (start, end) in enumerate(intervals):
        span = segments[start : end + 1]
        if start > 0:
            prev_seg = segments[start - 1]
            if prev_seg.label == sil:
                pad_start = (
                    prev_seg.start
                    if (idx == 0)
                    else int((prev_seg.start + prev_seg.end) / 2)
                )
                span = [Segment(sil, pad_start, span[0].start)] + span
        if end + 1 < len(segments):
            next_seg = segments[end + 1]
            if next_seg.label == sil:
                pad_end = (
                    next_seg.end
                    if (idx == len(intervals) - 1)
                    else math.floor((next_seg.start + next_seg.end) / 2)
                )
                span = span + [Segment(sil, span[-1].end, pad_end)]
        spans.append(span)
    return spans