import os
import sys
os.environ['HF_HUB_CACHE'] = './checkpoints/hf_cache'
import torch
import torch.multiprocessing as mp
import random
import librosa
import yaml
import argparse
import torchaudio
import torchaudio.compliance.kaldi as kaldi
import glob
from tqdm import tqdm
import shutil

from .modules.commons import recursive_munch, build_model, load_checkpoint
from .optimizers import build_optimizer
from .data.ft_dataset import build_ft_dataloader
from .hf_utils import load_custom_model_from_hf

class Trainer:
    def __init__(self,
                 config_path,
                 pretrained_ckpt_path,
                 data_dir,
                 run_name,
                 batch_size=0,
                 num_workers=0,
                 steps=1000,
                 save_interval=500,
                 max_epochs=1000,
                 device="cuda:0",
                 ):
        self.device = device
        config = yaml.safe_load(open(config_path))
        self.log_dir = os.path.join(config['log_dir'], run_name)
        os.makedirs(self.log_dir, exist_ok=True)
        # copy config file to log dir
        shutil.copyfile(config_path, os.path.join(self.log_dir, os.path.basename(config_path)))
        batch_size = config.get('batch_size', 10) if batch_size == 0 else batch_size
        self.max_steps = steps

        self.n_epochs = max_epochs
        self.log_interval = config.get('log_interval', 10)
        self.save_interval = save_interval

        self.sr = config['preprocess_params'].get('sr', 22050)
        self.hop_length = config['preprocess_params']['spect_params'].get('hop_length', 256)
        self.win_length = config['preprocess_params']['spect_params'].get('win_length', 1024)
        self.n_fft = config['preprocess_params']['spect_params'].get('n_fft', 1024)
        preprocess_params = config['preprocess_params']

        self.train_dataloader = build_ft_dataloader(
            data_dir,
            preprocess_params['spect_params'],
            self.sr,
            batch_size=batch_size,
            num_workers=num_workers,
        )
        self.f0_condition = config['model_params']['DiT'].get('f0_condition', False)
        self.build_sv_model(device, config)
        self.build_semantic_fn(device, config)
        if self.f0_condition:
            self.build_f0_fn(device, config)
        self.build_converter(device, config)
        self.build_vocoder(device, config)

        scheduler_params = {
            "warmup_steps": 0,
            "base_lr": 0.00001,
        }

        self.model_params = recursive_munch(config['model_params'])
        self.model = build_model(self.model_params, stage='DiT')

        _ = [self.model[key].to(device) for key in self.model]
        self.model.cfm.estimator.setup_caches(max_batch_size=batch_size, max_seq_length=8192)

        # initialize optimizers after preparing models for compatibility with FSDP
        self.optimizer = build_optimizer({key: self.model[key] for key in self.model},
                                         lr=float(scheduler_params['base_lr']))

        if pretrained_ckpt_path is None:
            # find latest checkpoint
            available_checkpoints = glob.glob(os.path.join(self.log_dir, "DiT_epoch_*_step_*.pth"))
            if len(available_checkpoints) > 0:
                latest_checkpoint = max(
                    available_checkpoints, key=lambda x: int(x.split("_")[-1].split(".")[0])
                )
                earliest_checkpoint = min(
                    available_checkpoints, key=lambda x: int(x.split("_")[-1].split(".")[0])
                )
                # delete the earliest checkpoint if we have more than 2
                if (
                    earliest_checkpoint != latest_checkpoint
                    and len(available_checkpoints) > 2
                ):
                    os.remove(earliest_checkpoint)
                    print(f"Removed {earliest_checkpoint}")
            elif config.get('pretrained_model', ''):
                latest_checkpoint = load_custom_model_from_hf("Plachta/Seed-VC", config['pretrained_model'], None)
            else:
                latest_checkpoint = ""
        else:
            assert os.path.exists(pretrained_ckpt_path), f"Pretrained checkpoint {pretrained_ckpt_path} not found"
            latest_checkpoint = pretrained_ckpt_path

        if os.path.exists(latest_checkpoint):
            self.model, self.optimizer, self.epoch, self.iters = load_checkpoint(
                self.model, self.optimizer, latest_checkpoint,
                load_only_params=True,
                ignore_modules=[],
                is_distributed=False
            )
            print(f"Loaded checkpoint from {latest_checkpoint}")
        else:
            self.epoch, self.iters = 0, 0
            print("Failed to load any checkpoint, training from scratch.")

    def build_sv_model(self, device, config):
        from .modules.campplus.DTDNN import CAMPPlus
        self.campplus_model = CAMPPlus(feat_dim=80, embedding_size=192)
        campplus_sd_path = load_custom_model_from_hf("funasr/campplus", "campplus_cn_common.bin", config_filename=None)
        campplus_sd = torch.load(campplus_sd_path, map_location='cpu')
        self.campplus_model.load_state_dict(campplus_sd)
        self.campplus_model.eval()
        self.campplus_model.to(device)
        self.sv_fn = self.campplus_model

    def build_f0_fn(self, device, config):
        from .modules.rmvpe import RMVPE
        model_path = load_custom_model_from_hf("lj1995/VoiceConversionWebUI", "rmvpe.pt", None)
        self.rmvpe = RMVPE(model_path, is_half=False, device=device)
        self.f0_fn = self.rmvpe

    def build_converter(self, device, config):
        from .modules.openvoice.api import ToneColorConverter
        ckpt_converter, config_converter = load_custom_model_from_hf("myshell-ai/OpenVoiceV2", "converter/checkpoint.pth", "converter/config.json")
        self.tone_color_converter = ToneColorConverter(config_converter, device=device)
        self.tone_color_converter.load_ckpt(ckpt_converter)
        self.tone_color_converter.model.eval()
        se_db_path = load_custom_model_from_hf("Plachta/Seed-VC", "se_db.pt", None)
        self.se_db = torch.load(se_db_path, map_location='cpu')

    def build_vocoder(self, device, config):
        vocoder_type = config['model_params']['vocoder']['type']
        vocoder_name = config['model_params']['vocoder'].get('name', None)
        if vocoder_type == 'bigvgan':
            from .modules.bigvgan import bigvgan
            self.bigvgan_model = bigvgan.BigVGAN.from_pretrained(vocoder_name, use_cuda_kernel=False)
            self.bigvgan_model.remove_weight_norm()
            self.bigvgan_model = self.bigvgan_model.eval().to(device)
            vocoder_fn = self.bigvgan_model
        elif vocoder_type == 'hifigan':
            from .modules.hifigan.generator import HiFTGenerator
            from .modules.hifigan.f0_predictor import ConvRNNF0Predictor
            hift_config = yaml.safe_load(open('configs/hifigan.yml', 'r'))
            hift_path = load_custom_model_from_hf("FunAudioLLM/CosyVoice-300M", 'hift.pt', None)
            self.hift_gen = HiFTGenerator(**hift_config['hift'],
                                          f0_predictor=ConvRNNF0Predictor(**hift_config['f0_predictor']))
            self.hift_gen.load_state_dict(torch.load(hift_path, map_location='cpu'))
            self.hift_gen.eval()
            self.hift_gen.to(device)
            vocoder_fn = self.hift_gen
        else:
            raise ValueError(f"Unsupported vocoder type: {vocoder_type}")
        self.vocoder_fn = vocoder_fn

    def build_semantic_fn(self, device, config):
        speech_tokenizer_type = config['model_params']['speech_tokenizer'].get('type', 'cosyvoice')
        if speech_tokenizer_type == 'whisper':
            from transformers import AutoFeatureExtractor, WhisperModel
            whisper_model_name = config['model_params']['speech_tokenizer']['name']
            self.whisper_model = WhisperModel.from_pretrained(whisper_model_name).to(device)
            self.whisper_feature_extractor = AutoFeatureExtractor.from_pretrained(whisper_model_name)
            # remove decoder to save memory
            del self.whisper_model.decoder

            def semantic_fn(waves_16k):
                ori_inputs = self.whisper_feature_extractor(
                    [w16k.cpu().numpy() for w16k in waves_16k],
                    return_tensors="pt",
                    return_attention_mask=True,
                    sampling_rate=16000,
                )
                ori_input_features = self.whisper_model._mask_input_features(
                    ori_inputs.input_features, attention_mask=ori_inputs.attention_mask
                ).to(device)
                with torch.no_grad():
                    ori_outputs = self.whisper_model.encoder(
                        ori_input_features.to(self.whisper_model.encoder.dtype),
                        head_mask=None,
                        output_attentions=False,
                        output_hidden_states=False,
                        return_dict=True,
                    )
                S_ori = ori_outputs.last_hidden_state.to(torch.float32)
                S_ori = S_ori[:, :waves_16k.size(-1) // 320 + 1]
                return S_ori

        elif speech_tokenizer_type == 'xlsr':
            from transformers import (
                Wav2Vec2FeatureExtractor,
                Wav2Vec2Model,
            )
            model_name = config['model_params']['speech_tokenizer']['name']
            output_layer = config['model_params']['speech_tokenizer']['output_layer']
            self.wav2vec_feature_extractor = Wav2Vec2FeatureExtractor.from_pretrained(model_name)
            self.wav2vec_model = Wav2Vec2Model.from_pretrained(model_name)
            self.wav2vec_model.encoder.layers = self.wav2vec_model.encoder.layers[:output_layer]
            self.wav2vec_model = self.wav2vec_model.to(device)
            self.wav2vec_model = self.wav2vec_model.eval()
            self.wav2vec_model = self.wav2vec_model.half()

            def semantic_fn(waves_16k):
                ori_waves_16k_input_list = [waves_16k[bib].cpu().numpy() for bib in range(len(waves_16k))]
                ori_inputs = self.wav2vec_feature_extractor(
                    ori_waves_16k_input_list,
                    return_tensors="pt",
                    return_attention_mask=True,
                    padding=True,
                    sampling_rate=16000
                ).to(device)
                with torch.no_grad():
                    ori_outputs = self.wav2vec_model(
                        ori_inputs.input_values.half(),
                    )
                S_ori = ori_outputs.last_hidden_state.float()
                return S_ori
        else:
            raise ValueError(f"Unsupported speech tokenizer type: {speech_tokenizer_type}")
        self.semantic_fn = semantic_fn

    def train_one_step(self, batch):
        waves, mels, wave_lengths, mel_input_length = batch

        B = waves.size(0)
        target_size = mels.size(2)
        target = mels
        target_lengths = mel_input_length

        # get speaker embedding
        if self.sr != 22050:
            waves_22k = torchaudio.functional.resample(waves, self.sr, 22050)
            wave_lengths_22k = (wave_lengths.float() * 22050 / self.sr).long()
        else:
            waves_22k = waves
            wave_lengths_22k = wave_lengths
        se_batch = self.tone_color_converter.extract_se(waves_22k, wave_lengths_22k)

        ref_se_idx = torch.randint(0, len(self.se_db), (B,))
        ref_se = self.se_db[ref_se_idx].to(self.device)

        # convert
        converted_waves_22k = self.tone_color_converter.convert(
            waves_22k, wave_lengths_22k, se_batch, ref_se
        ).squeeze(1)

        if self.sr != 22050:
            converted_waves = torchaudio.functional.resample(converted_waves_22k, 22050, self.sr)
        else:
            converted_waves = converted_waves_22k

        waves_16k = torchaudio.functional.resample(waves, self.sr, 16000)
        wave_lengths_16k = (wave_lengths.float() * 16000 / self.sr).long()
        converted_waves_16k = torchaudio.functional.resample(converted_waves, self.sr, 16000)

        # extract S_alt (perturbed speech tokens)
        S_ori = self.semantic_fn(waves_16k)
        S_alt = self.semantic_fn(converted_waves_16k)

        if self.f0_condition:
            F0_ori = self.rmvpe.infer_from_audio_batch(waves_16k)
        else:
            F0_ori = None

        # interpolate speech token to match acoustic feature length
        alt_cond, _, alt_codes, alt_commitment_loss, alt_codebook_loss = (
            self.model.length_regulator(S_alt, ylens=target_lengths, f0=F0_ori)
        )
        ori_cond, _, ori_codes, ori_commitment_loss, ori_codebook_loss = (
            self.model.length_regulator(S_ori, ylens=target_lengths, f0=F0_ori)
        )
        if alt_commitment_loss is None:
            alt_commitment_loss = 0
            alt_codebook_loss = 0
            ori_commitment_loss = 0
            ori_codebook_loss = 0

        # randomly set a length as prompt
        prompt_len_max = target_lengths - 1
        prompt_len = (torch.rand([B], device=alt_cond.device) * prompt_len_max).floor().long()
        prompt_len[torch.rand([B], device=alt_cond.device) < 0.1] = 0

        # for prompt cond token, use ori_cond instead of alt_cond
        cond = alt_cond.clone()
        for bib in range(B):
            cond[bib, :prompt_len[bib]] = ori_cond[bib, :prompt_len[bib]]

        # diffusion target
        common_min_len = min(target_size, cond.size(1))
        target = target[:, :, :common_min_len]
        cond = cond[:, :common_min_len]
        target_lengths = torch.clamp(target_lengths, max=common_min_len)
        x = target

        # style vectors are extracted from the prompt only
        feat_list = []
        for bib in range(B):
            feat = kaldi.fbank(
                waves_16k[bib:bib + 1, :wave_lengths_16k[bib]],
                num_mel_bins=80,
                dither=0,
                sample_frequency=16000
            )
            feat = feat - feat.mean(dim=0, keepdim=True)
            feat_list.append(feat)
        y_list = []
        with torch.no_grad():
            for feat in feat_list:
                y = self.sv_fn(feat.unsqueeze(0))
                y_list.append(y)
        y = torch.cat(y_list, dim=0)

        loss, _ = self.model.cfm(x, target_lengths, prompt_len, cond, y)

        loss_total = (
            loss +
            (alt_commitment_loss + ori_commitment_loss) * 0.05 +
            (ori_codebook_loss + alt_codebook_loss) * 0.15
        )

        self.optimizer.zero_grad()
        loss_total.backward()
        torch.nn.utils.clip_grad_norm_(self.model.cfm.parameters(), 10.0)
        torch.nn.utils.clip_grad_norm_(self.model.length_regulator.parameters(), 10.0)
        self.optimizer.step('cfm')
        self.optimizer.step('length_regulator')
        self.optimizer.scheduler(key='cfm')
        self.optimizer.scheduler(key='length_regulator')

        return loss.detach().item()

    def train_one_epoch(self):
        _ = [self.model[key].train() for key in self.model]
        for i, batch in enumerate(tqdm(self.train_dataloader)):
            batch = [b.to(self.device) for b in batch]
            loss = self.train_one_step(batch)
            self.ema_loss = (
                self.ema_loss * self.loss_smoothing_rate + loss * (1 - self.loss_smoothing_rate)
                if self.iters > 0 else loss
            )
            if self.iters % self.log_interval == 0:
                print(f"epoch {self.epoch}, step {self.iters}, loss: {self.ema_loss}")
            self.iters += 1

            if self.iters >= self.max_steps:
                break

            if self.iters % self.save_interval == 0:
                print('Saving..')
                state = {
                    'net': {key: self.model[key].state_dict() for key in self.model},
                    'optimizer': self.optimizer.state_dict(),
                    'scheduler': self.optimizer.scheduler_state_dict(),
                    'iters': self.iters,
                    'epoch': self.epoch,
                }
                save_path = os.path.join(
                    self.log_dir,
                    f'DiT_epoch_{self.epoch:05d}_step_{self.iters:05d}.pth'
                )
                torch.save(state, save_path)

                # find all checkpoints and remove old ones
                checkpoints = glob.glob(os.path.join(self.log_dir, 'DiT_epoch_*.pth'))
                if len(checkpoints) > 2:
                    checkpoints.sort(key=lambda x: int(x.split('_')[-1].split('.')[0]))
                    for cp in checkpoints[:-2]:
                        os.remove(cp)

    def train(self):
        self.ema_loss = 0
        self.loss_smoothing_rate = 0.99
        for epoch in range(self.n_epochs):
            self.epoch = epoch
            self.train_one_epoch()
            if self.iters >= self.max_steps:
                break

        print('Saving final model..')
        state = {
            'net': {key: self.model[key].state_dict() for key in self.model},
        }
        os.makedirs(self.log_dir, exist_ok=True)
        save_path = os.path.join(self.log_dir, 'ft_model.pth')
        torch.save(state, save_path)
        print(f"Final model saved at {save_path}")


def main(args):
    trainer = Trainer(
        config_path=args.config,
        pretrained_ckpt_path=args.pretrained_ckpt,
        data_dir=args.dataset_dir,
        run_name=args.run_name,
        batch_size=args.batch_size,
        steps=args.max_steps,
        max_epochs=args.max_epochs,
        save_interval=args.save_every,
        num_workers=args.num_workers,
        device=args.device
    )
    trainer.train()
    
if __name__ == '__main__':
    if sys.platform == 'win32':
        mp.freeze_support()
        mp.set_start_method('spawn', force=True)

    parser = argparse.ArgumentParser()
    parser.add_argument('--config', type=str, default='./configs/presets/config_dit_mel_seed_uvit_xlsr_tiny.yml')
    parser.add_argument('--pretrained-ckpt', type=str, default=None)
    parser.add_argument('--dataset-dir', type=str, default='/path/to/dataset')
    parser.add_argument('--run-name', type=str, default='my_run')
    parser.add_argument('--batch-size', type=int, default=2)
    parser.add_argument('--max-steps', type=int, default=1000)
    parser.add_argument('--max-epochs', type=int, default=1000)
    parser.add_argument('--save-every', type=int, default=500)
    parser.add_argument('--num-workers', type=int, default=0)
    parser.add_argument("--gpu", type=int, help="Which GPU id to use", default=0)
    args = parser.parse_args()
    if torch.backends.mps.is_available():
        args.device = "mps"
    else:
        args.device = f"cuda:{args.gpu}" if args.gpu else "cuda:0"
    main(args)
