import os
import itertools
import json
from pathlib import Path
from typing import Dict, Iterable, List, Tuple

import torch
import wandb
from omegaconf import OmegaConf

from transformers import AutoTokenizer

from models import MAGVITv2, OMadaModelLM
from models.modeling_emova_speech_tokenizer import EMOVASpeechTokenizer
from training.prompting_utils import UniversalPrompting


def load_train_config(path: str):
    cfg = OmegaConf.load(path)
    return cfg


def get_vq_model_image(cfg, device):
    vq_cfg = cfg.model.vq_model_image
    if getattr(vq_cfg, "pretrained_model_path", None):
        model = MAGVITv2().to(device)
        state_dict = torch.load(vq_cfg.pretrained_model_path)["model"]
        model.load_state_dict(state_dict)
        return model.eval()
    else:
        return MAGVITv2.from_pretrained(vq_cfg.vq_model_name).to(device).eval()


def get_vq_model_audio(cfg, device):
    vq_cfg = cfg.model.vq_model_audio
    # Always EMOVA for now
    model = EMOVASpeechTokenizer.from_pretrained(vq_cfg.vq_model_name)
    model = model.to(device)
    model.eval()
    return model


def build_uni_prompting(cfg) -> Tuple[UniversalPrompting, AutoTokenizer]:
    tokenizer = AutoTokenizer.from_pretrained(cfg.model.omada.tokenizer_path, padding_side="left")
    uni_prompting = UniversalPrompting(
        tokenizer,
        max_text_len=cfg.dataset.preprocessing.max_seq_length,
        max_audio_len=cfg.dataset.preprocessing.max_aud_length,
        special_tokens=(
            "<|soi|>", "<|eoi|>", "<|sov|>", "<|eov|>", "<|t2i|>",
            "<|mmu|>", "<|t2v|>", "<|v2v|>", "<|lvg|>",
            "<|i2i|>", "<|v2s|>", "<|s2s|>",
            "<|v2t|>", "<|s2t|>", "<|t2s|>", "<|soa|>", "<|eoa|>",
            "<|ti2ti|>", "<|t2ti|>",
        ),
        ignore_id=-100,
        cond_dropout_prob=cfg.training.cond_dropout_prob,
        use_reserved_token=True,
    )
    return uni_prompting, tokenizer


def load_omada_from_checkpoint(ckpt_unwrapped_dir: str, device, torch_dtype=torch.bfloat16) -> OMadaModelLM:
    """Load OMada model weights from an `unwrapped_model` directory.

    The helper used to rely on a hard-coded config path which broke when
    evaluating checkpoints from other training steps. We now detect the
    config.json co-located with the weights so any checkpoint exported by the
    trainer can be used directly.
    """

    ckpt_path = Path(ckpt_unwrapped_dir)
    if not ckpt_path.is_dir():
        raise FileNotFoundError(f"Expected an 'unwrapped_model' directory, got {ckpt_unwrapped_dir}")

    config_path = ckpt_path / "config.json"
    config_arg = str(config_path) if config_path.exists() else None

    model = OMadaModelLM.from_pretrained(
        ckpt_unwrapped_dir,
        torch_dtype=torch_dtype,
        config=config_arg,
        trust_remote_code=True,
    ).to(device)
    model.eval()
    return model


def list_checkpoints(ckpt_root: str) -> List[str]:
    """Return a sorted list of checkpoint 'unwrapped_model' dirs under a training output dir or a direct ckpt dir.
    Accepts either:
      - A path that already ends with 'unwrapped_model'
      - A path to 'checkpoint-XXXX' (we append 'unwrapped_model')
      - A path to the experiment output dir that contains many 'checkpoint-*'
    """
    p = Path(ckpt_root)
    if p.name == "unwrapped_model" and p.is_dir():
        return [str(p)]
    if p.name.startswith("checkpoint-") and p.is_dir():
        inner = p / "unwrapped_model"
        return [str(inner)] if inner.is_dir() else []
    # otherwise, collect children checkpoints
    outs = []
    for child in p.iterdir():
        if child.is_dir() and child.name.startswith("checkpoint-"):
            inner = child / "unwrapped_model"
            if inner.is_dir():
                outs.append(str(inner))
    # sort by numeric step if possible
    def step_key(s: str):
        try:
            return int(Path(s).parent.name.split("-")[-1])
        except Exception:
            return -1
    outs.sort(key=step_key)
    return outs


def grid_dict(product_space: Dict[str, Iterable]) -> List[Dict]:
    """Expand a dict of lists to a list of dict combinations.
    Example: {a:[1,2], b:["x"]} -> [{a:1,b:"x"},{a:2,b:"x"}]
    """
    keys = list(product_space.keys())
    values = [list(v if isinstance(v, (list, tuple)) else [v]) for v in product_space.values()]
    combos = []
    for vals in itertools.product(*values):
        combos.append({k: v for k, v in zip(keys, vals)})
    return combos


def init_wandb(infer_cfg: Dict, task: str, ckpt_path: str, hparams: Dict):
    wcfg = infer_cfg.get("wandb", {})
    project = wcfg.get("project", f"omada-inference-{task}")
    entity = wcfg.get("entity")
    group = wcfg.get("group", f"{task}")
    name_prefix = wcfg.get("name_prefix", f"{task}")
    step_str = Path(ckpt_path).parent.name
    run_name = f"{name_prefix}-{step_str}-" + ",".join([f"{k}={v}" for k, v in hparams.items()])
    tags = wcfg.get("tags", [])

    wandb.init(project=project, entity=entity, group=group, name=run_name, tags=tags, config={
        "task": task,
        "checkpoint": ckpt_path,
        "hparams": hparams,
    })


def safe_log_table(name: str, columns: List[str], rows: List[List]):
    try:
        table = wandb.Table(columns=columns)
        for r in rows:
            table.add_data(*r)
        wandb.log({name: table})
    except Exception:
        pass