import email
import os
from pathlib import Path
from typing import Any

from llama_index.core import Document
from llama_index.core.readers.base import BaseReader


def find_all_messages_directories(root: str | None = None) -> list[Path]:
    """
    Recursively find all 'Messages' directories under the given root.
    Returns a list of Path objects.
    """
    if root is None:
        # Auto-detect user's mail path
        home_dir = os.path.expanduser("~")
        root = os.path.join(home_dir, "Library", "Mail")

    messages_dirs = []
    for dirpath, _dirnames, _filenames in os.walk(root):
        if os.path.basename(dirpath) == "Messages":
            messages_dirs.append(Path(dirpath))
    return messages_dirs


class EmlxReader(BaseReader):
    """
    Apple Mail .emlx file reader with embedded metadata.

    Reads individual .emlx files from Apple Mail's storage format.
    """

    def __init__(self, include_html: bool = False) -> None:
        """
        Initialize.

        Args:
            include_html: Whether to include HTML content in the email body (default: False)
        """
        self.include_html = include_html

    def load_data(self, input_dir: str, **load_kwargs: Any) -> list[Document]:
        """
        Load data from the input directory containing .emlx files.

        Args:
            input_dir: Directory containing .emlx files
            **load_kwargs:
                max_count (int): Maximum amount of messages to read.
        """
        docs: list[Document] = []
        max_count = load_kwargs.get("max_count", 1000)
        count = 0
        total_files = 0
        successful_files = 0
        failed_files = 0

        print(f"Starting to process directory: {input_dir}")

        # Walk through the directory recursively
        for dirpath, dirnames, filenames in os.walk(input_dir):
            # Skip hidden directories
            dirnames[:] = [d for d in dirnames if not d.startswith(".")]

            for filename in filenames:
                # Check if we've reached the max count (skip if max_count == -1)
                if max_count > 0 and count >= max_count:
                    break

                if filename.endswith(".emlx"):
                    total_files += 1
                    filepath = os.path.join(dirpath, filename)
                    try:
                        # Read the .emlx file
                        with open(filepath, encoding="utf-8", errors="ignore") as f:
                            content = f.read()

                        # .emlx files have a length prefix followed by the email content
                        # The first line contains the length, followed by the email
                        lines = content.split("\n", 1)
                        if len(lines) >= 2:
                            email_content = lines[1]

                            # Parse the email using Python's email module
                            try:
                                msg = email.message_from_string(email_content)

                                # Extract email metadata
                                subject = msg.get("Subject", "No Subject")
                                from_addr = msg.get("From", "Unknown")
                                to_addr = msg.get("To", "Unknown")
                                date = msg.get("Date", "Unknown")

                                # Extract email body
                                body = ""
                                if msg.is_multipart():
                                    for part in msg.walk():
                                        if (
                                            part.get_content_type() == "text/plain"
                                            or part.get_content_type() == "text/html"
                                        ):
                                            if (
                                                part.get_content_type() == "text/html"
                                                and not self.include_html
                                            ):
                                                continue
                                            try:
                                                payload = part.get_payload(decode=True)
                                                if payload:
                                                    body += payload.decode("utf-8", errors="ignore")
                                            except Exception as e:
                                                print(f"Error decoding payload: {e}")
                                                continue
                                else:
                                    try:
                                        payload = msg.get_payload(decode=True)
                                        if payload:
                                            body = payload.decode("utf-8", errors="ignore")
                                    except Exception as e:
                                        print(f"Error decoding single part payload: {e}")
                                        body = ""

                                # Only create document if we have some content
                                if body.strip() or subject != "No Subject":
                                    # Create document content with metadata embedded in text
                                    doc_content = f"""
[File]: {filename}
[From]: {from_addr}
[To]: {to_addr}
[Subject]: {subject}
[Date]: {date}
[EMAIL BODY Start]:
{body}
"""

                                    # No separate metadata - everything is in the text
                                    doc = Document(text=doc_content, metadata={})
                                    docs.append(doc)
                                    count += 1
                                    successful_files += 1

                                    # Print first few successful files for debugging
                                    if successful_files <= 3:
                                        print(
                                            f"Successfully loaded: {filename} - Subject: {subject[:50]}..."
                                        )

                            except Exception as e:
                                failed_files += 1
                                if failed_files <= 5:  # Only print first few errors
                                    print(f"Error parsing email from {filepath}: {e}")
                                continue

                    except Exception as e:
                        failed_files += 1
                        if failed_files <= 5:  # Only print first few errors
                            print(f"Error reading file {filepath}: {e}")
                        continue

        print("Processing summary:")
        print(f"  Total .emlx files found: {total_files}")
        print(f"  Successfully loaded: {successful_files}")
        print(f"  Failed to load: {failed_files}")
        print(f"  Final documents: {len(docs)}")

        return docs