import json
import os
import requests
import sys # Added for command-line arguments
from agent import BasicAgent

# --- Constants ---
DEFAULT_API_URL = "https://agents-course-unit4-scoring.hf.space"
DOWNLOAD_DIR = "downloaded_task_files" # Directory to save downloaded files
QUESTIONS_FILE = "data/questions.json"
# QUESTION_INDEX = 3 # Removed global constant

def run_single_question_test(question_index: int): # Added question_index parameter
    """
    Fetches a single question by index, downloads its associated file (if any),
    runs the BasicAgent on it, and prints the answer.
    """
    # Create download directory if it doesn't exist
    try:
        os.makedirs(DOWNLOAD_DIR, exist_ok=True)
        print(f"Ensured download directory exists: {DOWNLOAD_DIR}")
    except OSError as e:
        print(f"Error creating download directory {DOWNLOAD_DIR}: {e}")
        return

    # 1. Load Questions
    try:
        with open(QUESTIONS_FILE, 'r') as f:
            questions_data = json.load(f)
        if not questions_data or not isinstance(questions_data, list) or len(questions_data) <= question_index:
            print(f"Error: Could not load question at index {question_index} (0-indexed) from {QUESTIONS_FILE}. Total questions: {len(questions_data) if isinstance(questions_data, list) else 'N/A'}")
            return
        item = questions_data[question_index]
        print(f"Loaded question {question_index + 1} (from 1-indexed input): {item.get('question')}")
    except FileNotFoundError:
        print(f"Error: Questions file not found at {QUESTIONS_FILE}")
        return
    except json.JSONDecodeError:
        print(f"Error: Could not decode JSON from {QUESTIONS_FILE}")
        return
    except Exception as e:
        print(f"Error loading or parsing {QUESTIONS_FILE}: {e}")
        return

    # 2. Instantiate Agent
    try:
        agent = BasicAgent()
        print("Agent instantiated successfully.")
    except Exception as e:
        print(f"Error instantiating agent: {e}")
        return

    task_id = item.get("task_id")
    question_text = item.get("question")
    file_name = item.get("file_name")
    local_file_path = None

    if not task_id or question_text is None:
        print(f"Skipping item with missing task_id or question: {item}")
        return

    if file_name:
        download_url = f"{DEFAULT_API_URL}/files/{task_id}"
        local_file_path = os.path.join(DOWNLOAD_DIR, file_name)
        print(f"Attempting to download file for task {task_id} (using task_id in URL): {file_name} from {download_url}")
        try:
            file_response = requests.get(download_url, stream=True, timeout=30)
            file_response.raise_for_status()
            with open(local_file_path, 'wb') as f:
                for chunk in file_response.iter_content(chunk_size=8192):
                    f.write(chunk)
            print(f"Successfully downloaded to {local_file_path}")
        except requests.exceptions.RequestException as e:
            print(f"Failed to download {file_name}: {e}")
            local_file_path = None # Ensure agent doesn't get a path to a non-existent/failed file
        except Exception as e:
            print(f"An unexpected error occurred downloading {file_name}: {e}")
            local_file_path = None
    else:
        print("No file associated with this question.")

    # 3. Run Agent on the single question
    try:
        print(f"Running agent on question: {question_text}")
        if local_file_path:
            print(f"Providing file: {local_file_path}")
        submitted_answer = agent(question_text, file_path=local_file_path)
        print(f"\n--- Agent's Answer for Task ID: {task_id} ---")
        print(submitted_answer)
        print("--- End of Answer ---")

    except Exception as e:
         print(f"Error running agent on task {task_id}: {e}")

def run_all_questions_test():
    """
    Runs the test for all questions in the QUESTIONS_FILE.
    """
    print("Attempting to run tests for all questions...")
    try:
        with open(QUESTIONS_FILE, 'r') as f:
            questions_data = json.load(f)
        if not questions_data or not isinstance(questions_data, list):
            print(f"Error: Could not load questions from {QUESTIONS_FILE} or it's not a list.")
            return
        
        num_questions = len(questions_data)
        if num_questions == 0:
            print(f"No questions found in {QUESTIONS_FILE}.")
            return

        print(f"Found {num_questions} questions to test.")
        for i in range(num_questions):
            print(f"\n--- Running Test for Question {i+1}/{num_questions} ---")
            run_single_question_test(i)
            print(f"--- Finished Test for Question {i+1}/{num_questions} ---\n")
        print("All question tests completed.")

    except FileNotFoundError:
        print(f"Error: Questions file not found at {QUESTIONS_FILE}")
    except json.JSONDecodeError:
        print(f"Error: Could not decode JSON from {QUESTIONS_FILE}")
    except Exception as e:
        print(f"An unexpected error occurred while running all questions: {e}")

if __name__ == "__main__":
    if len(sys.argv) < 2:
        print("Usage: python test_single_q.py <question_number | 'all'>")
        print("Example (single question): python test_single_q.py 4")
        print("Example (all questions): python test_single_q.py all")
        run_all_questions_test() # Default to running all if no argument is provided
        sys.exit(0)

    argument = sys.argv[1]

    if argument.lower() == "all":
        run_all_questions_test()
    else:
        try:
            question_number_arg = int(argument)
            if question_number_arg <= 0:
                print("Error: Question number must be a positive integer.")
                sys.exit(1)
            # Convert 1-indexed input to 0-indexed for list access
            question_idx_0_based = question_number_arg - 1
            run_single_question_test(question_idx_0_based)
        except ValueError:
            print("Error: Invalid argument. Please enter an integer for a specific question or 'all'.")
            sys.exit(1)