import io
import os
import re
import pathlib
import shutil
import subprocess
import pandas as pd
from datasets import load_dataset, get_dataset_config_names
from loguru import logger
from typing import List

UPLOAD_DIRECTORY = pathlib.Path("/app/uploaded_files")
CONFIG_PATH = pathlib.Path("/app/yourbench_config.yml")

# Ensure the upload directory exists
UPLOAD_DIRECTORY.mkdir(parents=True, exist_ok=True)

STAGES = [
    "ingestion",
    "upload_ingest_to_hub",
    "summarization",
    "chunking",
    "single_shot_question_generation",
    "answer_generation",
    #"evaluate_models",
    #"create_leaderboard"
    # "judge_answers", # to uncomment when fixed 
]


def save_files(files: List[pathlib.Path]) -> str:
    """Save uploaded files to the UPLOAD_DIRECTORY safely"""
    saved_paths = []

    for file in files:
        try:
            source_path = pathlib.Path(file)
            destination_path = UPLOAD_DIRECTORY / source_path.name

            if not source_path.exists():
                print(f"File not found: {source_path}")
                continue  # Skip missing files

            shutil.move(str(source_path), str(destination_path))
            saved_paths.append(str(destination_path))

        except Exception as e:
            print(f"Error moving file {file}: {e}")

    return (
        f"Files saved to: {', '.join(saved_paths)}"
        if saved_paths
        else "No files were saved"
    )

def update_dataset(stages, hf_org, hf_prefix):
    """
    Updates the dataset based on the provided stages and dataset configuration.
    """
    ingestion_df = pd.DataFrame()
    summarization_df = pd.DataFrame()
    single_hop_df = pd.DataFrame()
    answers_df = pd.DataFrame()

    # Construct dataset name from config
    dataset_name = f"{hf_org}/{hf_prefix}"

    # TODO: add cache dir
    # Will be able to group everything in one pass once the names get homogeneized
    if "ingestion" in stages:
        # TODO: why is the key "ingested" and not "ingestion"? (does not match the other splits)
        ingestion_ds = load_dataset(dataset_name, name="ingested", split="train", streaming=True)
        ingestion_df = pd.DataFrame([next(iter(ingestion_ds)) for _ in range(5)])
    if "summarization" in stages:
        summarization_ds = load_dataset(dataset_name, name="summarization", split="train", streaming=True)
        summarization_df = pd.DataFrame([next(iter(summarization_ds)) for _ in range(5)])
    if "single_shot_question_generation" in stages:
        single_hop_ds = load_dataset(dataset_name, name="single_shot_question_generation", split="train", streaming=True)
        single_hop_df = pd.DataFrame([next(iter(single_hop_ds)) for _ in range(5)])
    if "answer_generation" in stages:
        answers_ds = load_dataset(dataset_name, name="answer_generation", split="train", streaming=True)
        answers_df = pd.DataFrame([next(iter(answers_ds)) for _ in range(5)])
    
    return (ingestion_df, summarization_df, single_hop_df, answers_df)

class SubprocessManager:
    def __init__(self, command):
        self.command = command
        self.process = None
        self.output_stream = io.StringIO()
        self.exit_code = None

    def start_process(self, custom_env: dict | None):
        """Start the subprocess."""
        if self.is_running():
            logger.info("Process is already running")
            return

        self.output_stream = io.StringIO()
        self.exit_code = None
        
        try:
            logger.info(f"Starting process with command: {' '.join(self.command)}")
            self.process = subprocess.Popen(
                self.command,
                stdout=subprocess.PIPE,
                stderr=subprocess.STDOUT,  # Combine stderr with stdout
                text=True,
                bufsize=1,
                start_new_session=True,
                env=custom_env,
            )
            os.set_blocking(self.process.stdout.fileno(), False)
            logger.info(f"Started process with PID: {self.process.pid}")
        except Exception as e:
            logger.error(f"Failed to start process: {str(e)}")
            return

    def read_and_get_output(self):
        """Read subprocess output, capture it, and return log and completed stages."""
        current_output = ""
        completed_stages = []

        if self.process and self.process.stdout:
            try:
                while True:
                    line = self.process.stdout.readline()
                    if line:
                        self.output_stream.write(line)
                    else:
                        break
            except BlockingIOError:
                pass

            current_output = self.output_stream.getvalue()
            completed_stages = list(set(re.findall(r"Successfully completed stage: (\w+)", current_output)))

        return current_output, completed_stages

    def stop_process(self):
        """Terminate the subprocess."""
        if not self.is_running():
            logger.info("Process is not running")
            return
        logger.info("Sending SIGTERM to the Process")
        try:
            self.process.terminate()
            self.exit_code =  self.process.wait(timeout=5)  # Wait up to 5 seconds for process to terminate
            logger.info(f"Process terminated by user with exit code {self.exit_code}")
        except subprocess.TimeoutExpired:
            logger.warning("Process did not terminate within timeout, sending SIGKILL")
            self.kill_process()

    def kill_process(self):
        """Forcefully kill the subprocess"""
        if not self.is_running():
            logger.info("Process is not running")
            return
        logger.info("Sending SIGKILL to the Process")
        try:
            self.process.kill()
            self.exit_code = self.process.wait(timeout=5) # Wait up to 5 seconds for process to be killed
            logger.info(f"Process killed by user with exit code {self.exit_code}")
        except subprocess.TimeoutExpired:
            logger.error("Process could not be killed within timeout")

    def is_running(self):
        """Check if the subprocess is still running"""
        if self.process is None:
            return False

        return self.process.poll() is None

    def get_exit_details(self):
        """Return exit code and reason if process has terminated"""
        if self.process is None:
            return None, "Process was never started"
        
        if self.is_running():
            return None, "Process is still running"
        
        if not self.exit_code is None and self.exit_code != 0 :
            return self.exit_code, "Process exited abnormaly"

        return self.exit_code, "Process exited normaly"