#!/usr/bin/env python

# pip install transformers datasets torch soundfile jiwer

from datasets import load_dataset, Audio
from transformers import pipeline, WhisperProcessor
from torch.utils.data import DataLoader
import torch
from jiwer import wer as jiwer_wer
from jiwer import cer as jiwer_cer
import ipdb
import subprocess
import os

# 1. Load FLEURS Burmese test set, cast to 16 kHz audio
ds = load_dataset("google/fleurs", "km_kh", split="test", trust_remote_code=True)
ds = ds.cast_column("audio", Audio(sampling_rate=16_000))

from transformers import AutoModelForSpeechSeq2Seq, AutoProcessor, pipeline


device = "cuda:0" if torch.cuda.is_available() else "cpu"
torch_dtype = torch.float16 if torch.cuda.is_available() else torch.float32

model_id = "./ft-lid-whisper-fleurs-km_kh-small"

model = AutoModelForSpeechSeq2Seq.from_pretrained(
    model_id, torch_dtype=torch_dtype, low_cpu_mem_usage=True, use_safetensors=True
)
model.to(device)
whisper_model = "openai/whisper-large-v3"
processor = WhisperProcessor.from_pretrained(whisper_model)

asr = pipeline(
    "automatic-speech-recognition",
    model=model,
    tokenizer=processor.tokenizer,
    feature_extractor=processor.feature_extractor,
    torch_dtype=torch_dtype,
    chunk_length_s=30,
    batch_size=64,
    max_new_tokens=228,
    device=device,
    num_beams=1,                   # Use beam search for better quality
    do_sample=False,               # Disable sampling for deterministic output
    early_stopping=False,           # Stop when sufficient beams are complete
)


# 3. Batch‐wise transcription function
def transcribe_batch(batch):
    # `batch["audio"]` is a list of {"array": np.ndarray, ...}
    inputs = [ ex["array"] for ex in batch["audio"] ]
    outputs = asr(inputs, generate_kwargs={"language": "khmer"})  # returns a list of dicts with "text"
    # lower-case and strip to normalize for CER
    preds = [ out["text"].lower().strip() for out in outputs ]
    return {"prediction": preds}

# 4. Map over the dataset in chunks of, say, 32 examples at a time
result = ds.map(
    transcribe_batch,
    batched=True,
    batch_size=64,              # feed 32 audios → pipeline will sub-batch into 8s
    remove_columns=ds.column_names
)

# ipdb.set_trace()
# 5. Compute corpus-level CER with jiwer
# refs = "\n".join(t.lower().strip() for t in ds["transcription"])
# preds = "\n".join(t for t in result["prediction"])
# score = jiwer_cer(refs, preds)
ids = [key for key in ds["id"]]
refs = [t.lower().strip() for t in ds["transcription"]]
preds = [t for t in result["prediction"]]
score_cer = jiwer_cer(refs, preds)
score_wer = jiwer_wer(refs, preds)

print(f"CER on FLEURS km_kh: {score_cer*100:.2f}%")
print(f"WER on FLEURS km_kh: {score_wer*100:.2f}%")

# Function to add spaces between characters for CER calculation
def add_char_spaces(text):
    """Add spaces between each character for character-level evaluation"""
    return ' '.join(list(text.strip()))

with open("./km_kh_finetune.pred", "w") as pred_results:
    for key, pred in zip(ids, preds):
        pred_with_spaces = add_char_spaces(pred)
        pred_results.write("{} {}\n".format(key, pred_with_spaces))

with open("./km_kh.ref", "w") as ref_results:
    for key, ref in zip(ids, refs):
        ref_with_spaces = add_char_spaces(ref)
        ref_results.write("{} {}\n".format(key, ref_with_spaces))

# Generate WER file using compute-wer.py
print("Generating detailed WER analysis...")

# Check if compute-wer.py exists
compute_wer_script = "./compute-wer.py"
if not os.path.exists(compute_wer_script):
    # Try to find it in parent directories or common locations
    possible_locations = [
        "./compute-wer.py",
    ]
    for location in possible_locations:
        if os.path.exists(location):
            compute_wer_script = location
            break
    else:
        print(f"Warning: compute-wer.py not found. Tried: {[compute_wer_script] + possible_locations}")
        print("Skipping detailed WER analysis.")
        compute_wer_script = None

if compute_wer_script:
    try:
        # Run compute-wer.py with character-level analysis
        ref_file = "./km_kh.ref"
        hyp_file = "./km_kh_finetune.pred"
        wer_file = "./km_kh.wer"
        
        cmd = [
            "python", compute_wer_script,
            "--char=1",  # Character-level analysis
            "--v=1",     # Verbose output
            ref_file,
            hyp_file
        ]
        
        print(f"Running: {' '.join(cmd)} > {wer_file}")
        
        # Run the command and redirect output to wer file
        with open(wer_file, "w") as wer_output:
            result = subprocess.run(
                cmd,
                stdout=wer_output,
                stderr=subprocess.PIPE,
                text=True,
                check=True
            )
        
        print(f"CER analysis saved to {wer_file}")
        
        # Optionally, print the first few lines of the WER file
        if os.path.exists(wer_file):
            print("\nFirst few lines of WER analysis:")
            with open(wer_file, "r") as f:
                lines = f.readlines()
                for i, line in enumerate(lines[:10]):  # Show first 10 lines
                    print(f"  {line.rstrip()}")
                if len(lines) > 10:
                    print(f"  ... ({len(lines) - 10} more lines)")
        
    except subprocess.CalledProcessError as e:
        print(f"Error running compute-wer.py: {e}")
        if e.stderr:
            print(f"Error details: {e.stderr}")
    except Exception as e:
        print(f"Unexpected error: {e}")

print("Inference and CER analysis completed!")