"""Main CLI entry point."""

import sys
from pathlib import Path
from typing import Optional
import click
import torch

from taoTrain.config import load_config, load_tokenizer_config, TrainingModeEnum, PretrainConfig, SFTConfig, RLConfig
from taoTrain.utils import set_seed, get_device
from taoTrain.core import BaseModel, create_model, create_datasets
from taoTrain.data import get_dataloader
from taoTrain.training import PretrainTrainer, SFTTrainer, RLTrainer
from taoTrain.benchmarks import BenchmarkRunner
from taoTrain.tokenizers import TokenizerTrainer


@click.group()
def main():
    """TaoTrain: A clean, modular PyTorch LLM training framework."""
    pass


@main.command()
@click.option(
    "--config",
    type=click.Path(exists=True),
    required=True,
    help="Path to training config file (YAML or JSON)",
)
def pretrain(config: str):
    """Pretrain a language model."""
    _train_command(config, TrainingModeEnum.PRETRAIN)


@main.command()
@click.option(
    "--config",
    type=click.Path(exists=True),
    required=True,
    help="Path to training config file (YAML or JSON)",
)
def sft(config: str):
    """Supervised fine-tune a language model."""
    _train_command(config, TrainingModeEnum.SFT)


@main.command()
@click.option(
    "--config",
    type=click.Path(exists=True),
    required=True,
    help="Path to training config file (YAML or JSON)",
)
def rl(config: str):
    """Train with reinforcement learning."""
    _train_command(config, TrainingModeEnum.RL)


@main.command()
@click.option(
    "--config",
    type=click.Path(exists=True),
    required=True,
    help="Path to tokenizer config file (YAML or JSON)",
)
def train_tokenizer(config: str):
    """Train a SentencePiece tokenizer from a YAML/JSON config file."""
    try:
        click.echo("🚀 TaoTrain Tokenizer Trainer")
        click.echo(f"{'=' * 50}")
        
        # Load tokenizer config
        click.echo(f"Loading config from {config}...")
        tokenizer_config = load_tokenizer_config(config)
        
        # Train tokenizer from config
        result = TokenizerTrainer.train_from_config(tokenizer_config)
        
        # Display results
        click.echo(f"\n{'=' * 50}")
        click.echo("✅ Tokenizer Training Complete!")
        click.echo(f"\n📊 Configuration:")
        click.echo(f"   - Input file: {tokenizer_config.jsonl_path}")
        click.echo(f"   - Samples: {tokenizer_config.max_samples or 'all'}")
        click.echo(f"   - Output dir: {result['output_dir']}")
        click.echo(f"   - Vocab size: {result['vocab_size']}")
        click.echo(f"   - Model type: {result['model_type']}")
        
        if tokenizer_config.special_tokens:
            click.echo(f"   - Special tokens: {tokenizer_config.special_tokens}")
        
        click.echo(f"\n📁 Generated Files:")
        click.echo(f"   - Model: {result['model_file']}")
        click.echo(f"   - Vocab: {result['vocab_file']}")
        
        click.echo(f"\n📝 Next Steps:")
        click.echo(f"   1. Use this tokenizer in your pretraining config:")
        click.echo(f"       dataset:")
        click.echo(f"         local: true")
        click.echo(f"         jsonl_path: {tokenizer_config.jsonl_path}")
        click.echo(f"         tokenizer_path: {result['model_file']}")
        click.echo(f"")
        click.echo(f"   2. Run pretraining with:")
        click.echo(f"       train pretrain --config your_config.yaml")
        
    except ImportError as e:
        click.echo(f"❌ Error: {e}", err=True)
        sys.exit(1)
    except FileNotFoundError as e:
        click.echo(f"❌ File Error: {e}", err=True)
        sys.exit(1)
    except ValueError as e:
        click.echo(f"❌ Validation Error: {e}", err=True)
        sys.exit(1)
    except Exception as e:
        click.echo(f"❌ Unexpected Error: {e}", err=True)
        click.echo(f"   Please report this issue.", err=True)
        sys.exit(1)


@click.command()
@click.option(
    "--jsonl-path",
    type=click.Path(exists=True),
    required=True,
    help="Path to JSONL file containing training data",
)
@click.option(
    "--output-dir",
    type=click.Path(),
    default="tokenizers",
    help="Directory to save tokenizer files",
)
@click.option(
    "--vocab-size",
    type=int,
    default=50000,
    help="Vocabulary size for the tokenizer",
)
@click.option(
    "--model-type",
    type=click.Choice(["unigram", "bpe", "char", "word"]),
    default="unigram",
    help="SentencePiece model type",
)
@click.option(
    "--character-coverage",
    type=float,
    default=0.9995,
    help="Character coverage for SentencePiece",
)
@click.option(
    "--tokenizer-prefix",
    type=str,
    default=None,
    help="Prefix for tokenizer output files (default: model_type)",
)
def train_tokenizer_command(
    jsonl_path: str,
    output_dir: str,
    vocab_size: int,
    model_type: str,
    character_coverage: float,
    tokenizer_prefix: Optional[str],
):
    """Train a SentencePiece tokenizer from JSONL data."""
    try:
        click.echo("🚀 TaoTrain Tokenizer Trainer")
        click.echo(f"{'=' * 50}")
        
        # Train tokenizer
        result = TokenizerTrainer.train_sentencepiece(
            jsonl_path=jsonl_path,
            output_dir=output_dir,
            vocab_size=vocab_size,
            model_type=model_type,
            character_coverage=character_coverage,
            tokenizer_prefix=tokenizer_prefix,
        )
        
        # Display results
        click.echo(f"\n{'=' * 50}")
        click.echo("✅ Tokenizer Training Complete!")
        click.echo(f"\n📊 Configuration:")
        click.echo(f"   - Input file: {jsonl_path}")
        click.echo(f"   - Output dir: {result['output_dir']}")
        click.echo(f"   - Vocab size: {result['vocab_size']}")
        click.echo(f"   - Model type: {result['model_type']}")
        
        click.echo(f"\n📁 Generated Files:")
        click.echo(f"   - Model: {result['model_file']}")
        click.echo(f"   - Vocab: {result['vocab_file']}")
        
        click.echo(f"\n📝 Next Steps:")
        click.echo(f"   1. Use this tokenizer in your pretraining config:")
        click.echo(f"       dataset:")
        click.echo(f"         local: true")
        click.echo(f"         jsonl_path: {jsonl_path}")
        click.echo(f"         tokenizer_path: {result['model_file']}")
        click.echo(f"")
        click.echo(f"   2. Run pretraining with:")
        click.echo(f"       train pretrain --config your_config.yaml")
        
    except ImportError as e:
        click.echo(f"❌ Error: {e}", err=True)
        sys.exit(1)
    except FileNotFoundError as e:
        click.echo(f"❌ File Error: {e}", err=True)
        sys.exit(1)
    except ValueError as e:
        click.echo(f"❌ Validation Error: {e}", err=True)
        sys.exit(1)
    except Exception as e:
        click.echo(f"❌ Unexpected Error: {e}", err=True)
        click.echo(f"   Please report this issue.", err=True)
        sys.exit(1)


# Keep legacy CLI command as train-tokenizer-legacy for backward compatibility
main.add_command(train_tokenizer_command, name="train-tokenizer-legacy")


def _train_command(config_path: str, mode: TrainingModeEnum):
    """Internal training command."""
    try:
        # Load config
        click.echo(f"Loading config from {config_path}...")
        train_config = load_config(config_path, mode)
        
        # Set seed
        set_seed(train_config.seed)
        
        # Get device
        device = get_device(train_config.device)
        click.echo(f"Using device: {device}")
        
        # Create model
        click.echo("Creating model...")
        model = create_model(train_config, device)
        total_params, trainable_params = _count_params(model)
        click.echo(f"  - Total parameters: {total_params:,}")
        click.echo(f"  - Trainable parameters: {trainable_params:,}")
        
        # Load pretrained checkpoint if provided (for SFT/RL)
        if train_config.checkpoint_path:
            click.echo(f"Loading pretrained checkpoint from {train_config.checkpoint_path}...")
            from taoTrain.checkpointing.checkpoint import CheckpointManager
            checkpoint_manager = CheckpointManager(train_config.checkpoint_dir)
            checkpoint = checkpoint_manager.load(train_config.checkpoint_path, device=device)
            
            # CheckpointManager.load() normalizes format and ensures 'model_state' key exists
            if "model_state" in checkpoint:
                model.load_state_dict(checkpoint["model_state"], strict=False)
                click.echo("  ✓ Checkpoint loaded successfully")
            else:
                raise KeyError(f"Invalid checkpoint format: 'model_state' key not found. "
                             f"Available keys: {list(checkpoint.keys())}")


        
        # Create datasets
        click.echo("Loading datasets...")
        train_dataset, val_dataset = create_datasets(train_config)
        click.echo(f"  - Train samples: {len(train_dataset)}")
        if val_dataset:
            click.echo(f"  - Val samples: {len(val_dataset)}")
        
        # Select trainer
        if mode == TrainingModeEnum.PRETRAIN:
            trainer_class = PretrainTrainer
        elif mode == TrainingModeEnum.SFT:
            trainer_class = SFTTrainer
        elif mode == TrainingModeEnum.RL:
            trainer_class = RLTrainer
        else:
            raise ValueError(f"Unknown training mode: {mode}")
        
        # Create trainer
        click.echo("Setting up trainer...")
        trainer = trainer_class(
            model=model,
            train_dataset=train_dataset,
            val_dataset=val_dataset,
            config=train_config,
            device=device,
        )
        
        # Training loop
        click.echo("\nStarting training...\n")
        for epoch in range(train_config.num_epochs):
            if train_config.max_steps and trainer.global_step >= train_config.max_steps:
                break
            
            epoch_metrics = trainer.train_epoch()
            click.echo(f"\nEpoch {epoch + 1} complete")
            click.echo(f"  - Loss: {epoch_metrics.get('loss', 'N/A')}")
            click.echo(f"  - Learning rate: {epoch_metrics.get('lr', 'N/A')}")
        
        # Final checkpoint
        final_path = Path(train_config.checkpoint_dir) / "final_model.pt"
        trainer.save_checkpoint(final_path)
        click.echo(f"\nTraining complete! Final model saved to {final_path}")
        
        # Log finish
        trainer.logger.finish()
        
    except Exception as e:
        click.echo(f"Error during training: {e}", err=True)
        sys.exit(1)


@main.command()
@click.option(
    "--model",
    type=click.Path(exists=True),
    required=True,
    help="Path to model checkpoint",
)
@click.option(
    "--benchmark-type",
    type=click.Choice(["all", "perplexity", "throughput", "memory"]),
    default="all",
    help="Type of benchmark to run",
)
@click.option(
    "--batch-size",
    type=int,
    default=32,
    help="Batch size for benchmarking",
)
@click.option(
    "--seq-length",
    type=int,
    default=1024,
    help="Sequence length for benchmarking",
)
def benchmark(model: str, benchmark_type: str, batch_size: int, seq_length: int):
    """Benchmark a trained model."""
    try:
        click.echo(f"Loading model from {model}...")
        device = get_device("cuda")
        runner = BenchmarkRunner.load_from_checkpoint(model, device=device)
        
        click.echo("Running benchmarks...\n")
        
        if benchmark_type == "throughput" or benchmark_type == "all":
            click.echo("Throughput benchmark:")
            results = runner.benchmark_throughput(batch_size, seq_length)
            for key, val in results.items():
                click.echo(f"  {key}: {val:.2f}")
        
        if benchmark_type == "memory" or benchmark_type == "all":
            click.echo("\nMemory benchmark:")
            results = runner.benchmark_memory()
            for key, val in results.items():
                click.echo(f"  {key}: {val:.2f}")
        
        click.echo("\nBenchmarking complete!")
        
    except Exception as e:
        click.echo(f"Error during benchmarking: {e}", err=True)
        sys.exit(1)


@main.command()
@click.option("--repo", type=str, default=".aim", help="AimStack repository path")
def view_logs(repo: str):
    """View training logs with AimStack."""
    try:
        import subprocess
        click.echo(f"Opening AimStack dashboard for repo: {repo}")
        subprocess.run(["aim", "up", "--repo", repo])
    except FileNotFoundError:
        click.echo("Error: 'aim' command not found. Install with: pip install aim", err=True)
        sys.exit(1)


def _count_params(model: BaseModel) -> tuple[int, int]:
    """Count model parameters."""
    total = sum(p.numel() for p in model.parameters())
    trainable = sum(p.numel() for p in model.parameters() if p.requires_grad)
    return total, trainable


if __name__ == "__main__":
    main()