#!/usr/bin/env -S uv --quiet run --script
# /// script
# requires-python = ">=3.13"
# dependencies = [
#     "markdown-it-py",
#     "requests",
#     "tqdm",
# ]
# ///
import os
import base64
import mimetypes
import concurrent.futures
from pathlib import Path
from urllib.parse import urlparse
import re # Make sure re is imported

import requests
from markdown_it import MarkdownIt
# from markdown_it.renderer import RendererHTML # Not used in final regex approach
# from markdown_it.utils import OptionsDict # Not used
from tqdm import tqdm

# Configuration
MAX_WORKERS = 3
OUTPUT_DIR = Path("output")
REQUEST_TIMEOUT = 10  # seconds for network requests
VERBOSE = False # Set to True for detailed per-image logging, False for cleaner output

# Ensure mimetypes are initialized
mimetypes.init()

def get_image_mimetype(image_path_or_url, content=None):
    """Determines the MIME type of an image."""
    parsed_url = urlparse(image_path_or_url)
    if parsed_url.scheme in ['http', 'https']:
        if content:
            pass # Placeholder for more advanced content-based MIME detection
        mime_type, _ = mimetypes.guess_type(parsed_url.path)
        if mime_type:
            return mime_type
    else: # Local file
        mime_type, _ = mimetypes.guess_type(image_path_or_url)
        if mime_type:
            return mime_type
    # Default or if unable to determine
    ext = Path(image_path_or_url).suffix.lower()
    if ext == ".png": return "image/png"
    if ext in [".jpg", ".jpeg"]: return "image/jpeg"
    if ext == ".gif": return "image/gif"
    if ext == ".svg": return "image/svg+xml"
    if ext == ".webp": return "image/webp"
    return "application/octet-stream"

def image_to_base64(image_src, md_file_path: Path):
    """
    Converts an image (local or remote) to a base64 data URI.
    Returns (data_uri_string_or_None, status_message_or_None)
    """
    log_messages = []
    try:
        parsed_url = urlparse(image_src)
        image_data = None
        content_type_header = None

        if parsed_url.scheme in ['http', 'https']:
            if VERBOSE: log_messages.append(f"      Fetching remote: {image_src[:70]}...")
            response = requests.get(image_src, timeout=REQUEST_TIMEOUT, stream=True)
            response.raise_for_status()
            image_data = response.content
            content_type_header = response.headers.get('Content-Type')
        elif not parsed_url.scheme and not parsed_url.netloc:
            base_dir = md_file_path.parent
            local_image_path = (base_dir / image_src).resolve()
            
            if local_image_path.is_file():
                if VERBOSE: log_messages.append(f"      Reading local: {local_image_path.name}")
                with open(local_image_path, "rb") as f:
                    image_data = f.read()
            else:
                return None, f"      ERROR: Local image not found: {local_image_path} (referenced in {md_file_path.name})"
        else:
            return None, f"      WARNING: Unsupported image scheme: {image_src} (in {md_file_path.name})"

        if image_data:
            base64_encoded_data = base64.b64encode(image_data).decode('utf-8')
            mime_type = content_type_header or get_image_mimetype(image_src, image_data)
            if VERBOSE: log_messages.append(f"      Encoded {image_src[:50]}... as {mime_type}")
            return f"data:{mime_type};base64,{base64_encoded_data}", "\n".join(log_messages) if log_messages else None

    except requests.exceptions.RequestException as e:
        return None, f"      ERROR fetching {image_src[:70]}...: {e} (in {md_file_path.name})"
    except IOError as e:
        return None, f"      ERROR reading {image_src}: {e} (in {md_file_path.name})"
    except Exception as e:
        return None, f"      ERROR processing {image_src}: {e} (in {md_file_path.name})"
    
    # Fallback if something unexpected happened before returning
    final_message = "\n".join(log_messages) if log_messages else None
    if not image_data and not final_message: # Ensure there's a message if we fall through without success
        final_message = f"      ERROR: Unknown issue processing image {image_src} (in {md_file_path.name})"
    return None, final_message


def process_markdown_file(md_file_path: Path, output_base_dir: Path):
    """
    Reads a Markdown file, embeds images, and saves it to the output directory.
    Returns (success_boolean, list_of_human_readable_messages)
    """
    file_operation_messages = []
    if VERBOSE:
        file_operation_messages.append(f"Starting processing: {md_file_path}")

    try:
        relative_path = md_file_path.relative_to(Path.cwd())
        output_file_path = output_base_dir / relative_path
        output_file_path.parent.mkdir(parents=True, exist_ok=True)

        with open(md_file_path, "r", encoding="utf-8") as f:
            content = f.read()

        image_pattern = re.compile(r"!\[(.*?)\]\((.*?)(?: \"(.*?)\")?\)")
        
        processed_image_links_count = 0
        successfully_embedded_count = 0

        def replacer(match):
            nonlocal processed_image_links_count, successfully_embedded_count # Allow modification
            alt_text = match.group(1)
            original_src = match.group(2)
            title_text = match.group(3) if match.group(3) else ""

            if original_src.startswith("data:"): # Already embedded
                return match.group(0)

            processed_image_links_count += 1
            if VERBOSE:
                file_operation_messages.append(f"    Found image link: {original_src[:70]}... in {md_file_path.name}")
            
            base64_uri, image_status_msg = image_to_base64(original_src, md_file_path)
            
            if image_status_msg: # Add any messages from image_to_base64
                # Only add detailed image status if VERBOSE, or if it's an error/warning
                if VERBOSE or "ERROR" in image_status_msg.upper() or "WARNING" in image_status_msg.upper():
                     file_operation_messages.append(image_status_msg)

            if base64_uri:
                successfully_embedded_count += 1
                new_tag = f"![{alt_text}]({base64_uri}"
                if title_text:
                    new_tag += f' "{title_text}"'
                new_tag += ")"
                if VERBOSE:
                    file_operation_messages.append(f"      Embedded: {original_src[:50]}...")
                return new_tag
            else:
                # If embedding failed and no specific error was added from image_to_base64, add a generic one
                if not any(msg for msg in file_operation_messages if original_src in msg and ("ERROR" in msg.upper() or "WARNING" in msg.upper())):
                    file_operation_messages.append(f"      WARNING: Failed to embed {original_src[:70]}... (in {md_file_path.name}). Kept original.")
                return match.group(0) # Return original match if embedding fails

        modified_content = image_pattern.sub(replacer, content)

        with open(output_file_path, "w", encoding="utf-8") as f:
            f.write(modified_content)
        
        # Summary for this file
        summary_msg = f"Finished: {md_file_path.name}."
        if processed_image_links_count > 0:
            summary_msg += f" (Found: {processed_image_links_count}, Embedded: {successfully_embedded_count}"
            failures = processed_image_links_count - successfully_embedded_count
            if failures > 0:
                summary_msg += f", Failed/Skipped: {failures}"
            summary_msg += ")"
        elif VERBOSE: # Only if verbose and no images were found
            summary_msg += " (No image links applicable for embedding)."
        file_operation_messages.append(summary_msg)
        
        return True, file_operation_messages

    except Exception as e:
        err_msg = f"  Major ERROR processing file {md_file_path.name}: {e}"
        if VERBOSE:
            import traceback
            err_msg += "\n" + traceback.format_exc()
        file_operation_messages.append(err_msg)
        return False, file_operation_messages


def main():
    """
    Main function to find Markdown files and process them.
    """
    OUTPUT_DIR.mkdir(parents=True, exist_ok=True)
    
    current_dir = Path.cwd()
    md_files = [
        p for p in current_dir.rglob("*.md") 
        if not str(p.resolve()).startswith(str(OUTPUT_DIR.resolve()))
    ]

    if not md_files:
        print("No Markdown files found in the current directory (excluding 'output' directory).")
        return

    print(f"Found {len(md_files)} Markdown files to process. VERBOSE output is {'ON' if VERBOSE else 'OFF'}.")

    successful_count = 0
    failed_count = 0

    with concurrent.futures.ThreadPoolExecutor(max_workers=MAX_WORKERS) as executor:
        future_to_file = {
            executor.submit(process_markdown_file, md_file, OUTPUT_DIR): md_file 
            for md_file in md_files
        }
        
        for future in tqdm(concurrent.futures.as_completed(future_to_file), total=len(md_files), desc="Embedding Images"):
            md_file = future_to_file[future]
            try:
                success, messages = future.result()
                if messages:
                    for msg in messages:
                        # Use tqdm.write to print messages without breaking the progress bar
                        # Add a file context to messages if not already clear
                        if md_file.name not in msg and VERBOSE: # Check helps avoid redundant file name prints
                             tqdm.write(f"[{md_file.name}] {msg}")
                        else:
                             tqdm.write(msg)
                
                if success:
                    successful_count +=1
                else:
                    failed_count += 1
                    # The error message should already be in 'messages' and printed by tqdm.write
            except Exception as exc: # Catches exceptions from the worker task logic itself, if not handled by process_markdown_file
                tqdm.write(f"  Critical unhandled exception for {md_file.name}: {exc}")
                failed_count += 1
                if VERBOSE:
                    import traceback
                    tqdm.write(traceback.format_exc())

    print("\n--- Summary ---")
    print(f"Successfully processed files: {successful_count}")
    print(f"Files with errors/failures: {failed_count}")
    print(f"Output files are in: {OUTPUT_DIR.resolve()}")

if __name__ == "__main__":
    main()