#!/usr/bin/env python3
"""
Outline API Import Script
Imports markdown files back into Outline wiki with hierarchy preservation.
Companion script to outline_export_fixed.py.

Usage:
    python3 outline_import.py [OPTIONS]

Options:
    -s, --single        Import all into single timestamped collection
    -n, --dry-run       Preview operations without making changes
    -d, --source DIR    Source directory (default: outline_export)
    -v, --verbose       Increase verbosity (-vv for debug)
    -f, --force         Overwrite existing collections
    --settings FILE     Path to settings file (default: settings.json)
    -h, --help          Show help message
"""

import os
import sys
import json
import logging
import time
import argparse
from datetime import datetime
from pathlib import Path
from typing import Dict, List, Optional, Tuple

import requests
from requests.adapters import HTTPAdapter
from urllib3.util.retry import Retry

# Configure logging
logging.basicConfig(
    level=logging.INFO,
    format='%(asctime)s | %(levelname)-8s | %(message)s',
    datefmt='%H:%M:%S'
)
logger = logging.getLogger('outline_import')


class OutlineImporter:
    """Import documents into Outline with hierarchy preservation."""

    def __init__(
        self,
        base_url: str,
        api_token: str,
        source_dir: str = "outline_export",
        dry_run: bool = False,
        single_mode: bool = False,
        force: bool = False,
        on_collection_exists: str = "skip",
        on_document_exists: str = "skip",
        default_permission: str = "read_write",
        request_timeout: int = 30,
        retry_attempts: int = 3,
        retry_delay: float = 1.0,
        rate_limit_delay: float = 0.1
    ):
        self.base_url = base_url.rstrip('/')
        self.api_token = api_token
        self.source_dir = Path(source_dir)
        self.dry_run = dry_run
        self.single_mode = single_mode
        self.force = force
        self.on_collection_exists = on_collection_exists
        self.on_document_exists = on_document_exists
        self.default_permission = default_permission
        self.request_timeout = request_timeout
        self.retry_attempts = retry_attempts
        self.retry_delay = retry_delay
        self.rate_limit_delay = rate_limit_delay

        # Setup session with retry logic
        self.session = requests.Session()
        retry_strategy = Retry(
            total=3,
            backoff_factor=1,
            status_forcelist=[429, 500, 502, 503, 504],
        )
        adapter = HTTPAdapter(max_retries=retry_strategy)
        self.session.mount("http://", adapter)
        self.session.mount("https://", adapter)

        self.headers = {
            "Authorization": f"Bearer {self.api_token}",
            "Content-Type": "application/json"
        }

        # ID mapping: old_id -> new_id
        self.id_map: Dict[str, str] = {}

        # Track existing collections
        self.existing_collections: Dict[str, str] = {}  # name -> id

        # Statistics
        self.stats = {
            "collections_created": 0,
            "collections_skipped": 0,
            "collections_errors": 0,
            "documents_created": 0,
            "documents_skipped": 0,
            "documents_errors": 0,
        }

        # Error tracking
        self.errors: List[Dict] = []

    def _api_request(
        self,
        endpoint: str,
        data: Optional[Dict] = None,
        method: str = "POST"
    ) -> Optional[Dict]:
        """
        Make API request with error handling and retry logic.

        Args:
            endpoint: API endpoint path (e.g., '/api/collections.list')
            data: Request body data
            method: HTTP method (POST or GET)

        Returns:
            Response data dict or None on failure
        """
        url = f"{self.base_url}{endpoint}"

        for attempt in range(self.retry_attempts):
            try:
                if method == "POST":
                    response = self.session.post(
                        url,
                        headers=self.headers,
                        json=data or {},
                        timeout=self.request_timeout
                    )
                else:
                    response = self.session.get(
                        url,
                        headers=self.headers,
                        timeout=self.request_timeout
                    )

                if response.status_code == 200:
                    return response.json()
                elif response.status_code in [429, 500, 502, 503, 504]:
                    if attempt < self.retry_attempts - 1:
                        wait_time = self.retry_delay * (2 ** attempt)
                        logger.warning(
                            f"API error {response.status_code} on {endpoint}, "
                            f"retrying in {wait_time:.1f}s (attempt {attempt + 1}/{self.retry_attempts})"
                        )
                        time.sleep(wait_time)
                        continue

                # Non-retryable error or final attempt
                logger.error(f"API error on {endpoint}: HTTP {response.status_code}")
                logger.debug(f"Response: {response.text[:200]}")
                return None

            except requests.RequestException as e:
                if attempt < self.retry_attempts - 1:
                    wait_time = self.retry_delay * (2 ** attempt)
                    logger.warning(
                        f"Request failed on {endpoint}: {e}, "
                        f"retrying in {wait_time:.1f}s"
                    )
                    time.sleep(wait_time)
                else:
                    logger.error(f"All {self.retry_attempts} attempts failed on {endpoint}: {e}")
                    return None

        return None

    def health_check(self) -> bool:
        """
        Verify API connectivity and authentication.

        Returns:
            True if API is accessible and authenticated
        """
        logger.info("Checking API connectivity...")
        result = self._api_request("/api/auth.info")
        if result and "data" in result:
            user = result["data"].get("user", {})
            team = result["data"].get("team", {})
            logger.info(f"Authenticated as: {user.get('name', 'Unknown')} ({user.get('email', 'N/A')})")
            logger.info(f"Team: {team.get('name', 'Unknown')}")
            return True
        logger.error("Health check failed: Unable to verify authentication")
        return False

    def _get_collections(self) -> List[Dict]:
        """Fetch all existing collections from Outline."""
        result = self._api_request("/api/collections.list")
        if result and "data" in result:
            collections = result["data"]
            # Cache name -> id mapping
            self.existing_collections = {c["name"]: c["id"] for c in collections}
            return collections
        return []

    def _create_collection(self, name: str, permission: str = None) -> Optional[str]:
        """
        Create a new collection.

        Args:
            name: Collection name
            permission: Permission level ('read' or 'read_write')

        Returns:
            Collection ID if created, None on failure
        """
        if permission is None:
            permission = self.default_permission

        if self.dry_run:
            logger.info(f"  [DRY RUN] Would create collection \"{name}\"")
            return "dry-run-collection-id"

        result = self._api_request("/api/collections.create", {
            "name": name,
            "permission": permission
        })

        if result and "data" in result:
            collection_id = result["data"]["id"]
            logger.debug(f"Created collection: {name} (id: {collection_id})")
            self.existing_collections[name] = collection_id
            return collection_id

        logger.error(f"Failed to create collection: {name}")
        return None

    def _delete_collection(self, collection_id: str) -> bool:
        """
        Delete a collection.

        Args:
            collection_id: Collection ID to delete

        Returns:
            True if deleted successfully
        """
        if self.dry_run:
            logger.info(f"  [DRY RUN] Would delete collection {collection_id}")
            return True

        result = self._api_request("/api/collections.delete", {"id": collection_id})
        return result is not None

    def _create_document(
        self,
        collection_id: str,
        title: str,
        text: str,
        parent_document_id: Optional[str] = None,
        publish: bool = True
    ) -> Optional[str]:
        """
        Create a new document in a collection.

        Args:
            collection_id: Parent collection ID
            title: Document title
            text: Markdown content
            parent_document_id: Optional parent document ID for nesting
            publish: Whether to publish immediately

        Returns:
            Document ID if created, None on failure
        """
        if self.dry_run:
            return "dry-run-document-id"

        data = {
            "collectionId": collection_id,
            "title": title,
            "text": text,
            "publish": publish
        }
        if parent_document_id:
            data["parentDocumentId"] = parent_document_id

        # Rate limiting
        if self.rate_limit_delay > 0:
            time.sleep(self.rate_limit_delay)

        result = self._api_request("/api/documents.create", data)

        if result and "data" in result:
            return result["data"]["id"]

        logger.error(f"Failed to create document: {title}")
        return None

    def _get_documents_in_collection(self, collection_id: str) -> List[Dict]:
        """Fetch all documents in a collection."""
        result = self._api_request("/api/documents.list", {"collectionId": collection_id})
        if result and "data" in result:
            return result["data"]
        return []

    def load_collection_metadata(self, collection_dir: Path) -> Optional[Dict]:
        """
        Load _collection_metadata.json from a collection directory.

        Args:
            collection_dir: Path to collection directory

        Returns:
            Metadata dict or None if not found/invalid
        """
        metadata_path = collection_dir / "_collection_metadata.json"
        if not metadata_path.exists():
            logger.warning(f"No metadata file found in {collection_dir}")
            return None

        try:
            with open(metadata_path, 'r', encoding='utf-8') as f:
                return json.load(f)
        except json.JSONDecodeError as e:
            logger.error(f"Invalid JSON in {metadata_path}: {e}")
            return None
        except Exception as e:
            logger.error(f"Error reading {metadata_path}: {e}")
            return None

    def get_source_collections(self) -> List[Path]:
        """
        Get list of collection directories from source.

        Returns:
            List of collection directory paths
        """
        if not self.source_dir.exists():
            logger.error(f"Source directory not found: {self.source_dir}")
            return []

        collections = []
        for item in sorted(self.source_dir.iterdir()):
            if item.is_dir() and not item.name.startswith('.'):
                # Check for metadata file
                if (item / "_collection_metadata.json").exists():
                    collections.append(item)
                else:
                    logger.warning(f"Skipping {item.name}: no metadata file")

        return collections

    def build_document_tree(self, documents: List[Dict]) -> List[Dict]:
        """
        Build ordered document tree from flat metadata list.
        Uses topological sort to ensure parents are created before children.

        Args:
            documents: List of document metadata dicts from _collection_metadata.json

        Returns:
            List of root documents with nested children
        """
        # Build lookup by ID
        doc_by_id: Dict[str, Dict] = {}
        for doc in documents:
            doc_by_id[doc["id"]] = doc.copy()
            doc_by_id[doc["id"]]["_children"] = []

        # Build parent-child relationships
        roots = []
        for doc in documents:
            parent_id = doc.get("parent_id")
            if parent_id and parent_id in doc_by_id:
                doc_by_id[parent_id]["_children"].append(doc_by_id[doc["id"]])
            else:
                roots.append(doc_by_id[doc["id"]])

        return roots

    def flatten_for_import(self, doc_tree: List[Dict], result: List[Dict] = None) -> List[Dict]:
        """
        Flatten document tree in topological order (parents before children).

        Args:
            doc_tree: Nested document tree
            result: Accumulator list (used internally)

        Returns:
            Flat list of documents in import order
        """
        if result is None:
            result = []

        for doc in doc_tree:
            # Add this document
            result.append({
                "id": doc["id"],
                "title": doc["title"],
                "filename": doc["filename"],
                "parent_id": doc.get("parent_id"),
            })
            # Then add children recursively
            children = doc.get("_children", []) or doc.get("children", [])
            if children:
                self.flatten_for_import(children, result)

        return result

    def read_document_content(self, collection_dir: Path, filename: str) -> Optional[str]:
        """
        Read markdown content from file.

        Args:
            collection_dir: Path to collection directory
            filename: Document filename

        Returns:
            Markdown content or None if not found
        """
        filepath = collection_dir / filename
        if not filepath.exists():
            logger.warning(f"File not found: {filepath}")
            return None

        try:
            with open(filepath, 'r', encoding='utf-8') as f:
                content = f.read()

            # Strip the header metadata added by export
            # Format: # Title\n\n<!-- metadata -->\n\n---\n\nActual content
            lines = content.split('\n')
            content_start = 0

            for i, line in enumerate(lines):
                if line.strip() == '---':
                    content_start = i + 1
                    break

            if content_start > 0 and content_start < len(lines):
                return '\n'.join(lines[content_start:]).strip()

            return content

        except Exception as e:
            logger.error(f"Error reading {filepath}: {e}")
            return None

    def import_collection(
        self,
        collection_dir: Path,
        target_collection_id: Optional[str] = None,
        parent_document_id: Optional[str] = None
    ) -> Tuple[int, int, int]:
        """
        Import a single collection.

        Args:
            collection_dir: Path to collection directory
            target_collection_id: Override target collection (for single mode)
            parent_document_id: Parent document ID (for single mode)

        Returns:
            Tuple of (created, skipped, errors)
        """
        metadata = self.load_collection_metadata(collection_dir)
        if not metadata:
            self.stats["collections_errors"] += 1
            self.errors.append({
                "type": "collection",
                "name": collection_dir.name,
                "error": "Invalid or missing metadata"
            })
            return (0, 0, 1)

        collection_name = metadata.get("name", collection_dir.name)
        documents = metadata.get("documents", [])

        # Count documents recursively
        def count_docs(docs):
            count = 0
            for doc in docs:
                count += 1
                count += count_docs(doc.get("children", []))
            return count

        doc_count = count_docs(documents)

        # Determine collection ID
        collection_id = target_collection_id
        if not collection_id:
            # Check if collection exists
            if collection_name in self.existing_collections:
                if self.force:
                    logger.info(f"  Deleting existing collection \"{collection_name}\"...")
                    if not self.dry_run:
                        self._delete_collection(self.existing_collections[collection_name])
                        del self.existing_collections[collection_name]
                else:
                    logger.info(f"  Collection exists, skipping...")
                    self.stats["collections_skipped"] += 1
                    return (0, doc_count, 0)

            # Create collection
            logger.info(f"  Creating collection...")
            collection_id = self._create_collection(collection_name)
            if not collection_id:
                self.stats["collections_errors"] += 1
                self.errors.append({
                    "type": "collection",
                    "name": collection_name,
                    "error": "Failed to create collection"
                })
                return (0, 0, 1)

            if not self.dry_run:
                logger.info(f"  ✓ (id: {collection_id[:8]}...)")
            self.stats["collections_created"] += 1

        # Build document tree and flatten for import
        doc_tree = self.build_document_tree(documents)
        import_order = self.flatten_for_import(doc_tree)

        # Import documents
        created = 0
        skipped = 0
        errors = 0

        for doc_meta in import_order:
            old_id = doc_meta["id"]
            title = doc_meta["title"]
            filename = doc_meta["filename"]
            old_parent_id = doc_meta.get("parent_id")

            # Resolve parent ID
            new_parent_id = parent_document_id  # Default for single mode
            if old_parent_id:
                new_parent_id = self.id_map.get(old_parent_id)
                if not new_parent_id and not self.dry_run:
                    logger.warning(f"Parent not found for {title}, creating as root-level")

            # Read content
            content = self.read_document_content(collection_dir, filename)
            if content is None:
                self._print_doc_status(title, "error", "file not found")
                errors += 1
                self.stats["documents_errors"] += 1
                self.errors.append({
                    "type": "document",
                    "title": title,
                    "collection": collection_name,
                    "error": "File not found"
                })
                continue

            # Create document
            new_id = self._create_document(
                collection_id,
                title,
                content,
                parent_document_id=new_parent_id
            )

            if new_id:
                self.id_map[old_id] = new_id
                self._print_doc_status(title, "created")
                created += 1
                self.stats["documents_created"] += 1
            else:
                self._print_doc_status(title, "error", "API error")
                errors += 1
                self.stats["documents_errors"] += 1
                self.errors.append({
                    "type": "document",
                    "title": title,
                    "collection": collection_name,
                    "error": "API error during creation"
                })

        return (created, skipped, errors)

    def _print_doc_status(self, title: str, status: str, message: str = None):
        """Print document import status."""
        if status == "created":
            symbol = "✓"
            label = "created"
        elif status == "skipped":
            symbol = "○"
            label = "skipped"
        else:
            symbol = "✗"
            label = message or "error"

        # This will be enhanced in Phase 6 with tree formatting
        logger.info(f"    {symbol} {title[:50]:<50} {label}")

    def import_all(self) -> None:
        """Import all collections from source directory."""
        start_time = time.time()

        # Print header
        mode_str = "Single collection" if self.single_mode else "Collection per folder"
        dry_run_str = " (DRY RUN)" if self.dry_run else ""

        print("=" * 60)
        print(f"  OUTLINE IMPORT{dry_run_str}")
        print("=" * 60)
        print()
        print(f"Source:  {self.source_dir}/")
        print(f"Target:  {self.base_url}")
        print(f"Mode:    {mode_str}")
        print()

        if self.dry_run:
            print("[DRY RUN] No changes will be made")
            print()

        # Health check
        if not self.health_check():
            logger.error("Import aborted due to failed health check")
            return

        print()

        # Get existing collections
        self._get_collections()

        # Get source collections
        source_collections = self.get_source_collections()
        if not source_collections:
            logger.error("No collections found in source directory")
            return

        if self.single_mode:
            # Single collection mode
            timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
            single_collection_name = f"import_{timestamp}"

            logger.info(f"Creating single collection: {single_collection_name}")
            collection_id = self._create_collection(single_collection_name)
            if not collection_id and not self.dry_run:
                logger.error("Failed to create import collection")
                return

            self.stats["collections_created"] += 1

            for collection_dir in source_collections:
                metadata = self.load_collection_metadata(collection_dir)
                if not metadata:
                    continue

                collection_name = metadata.get("name", collection_dir.name)
                doc_count = metadata.get("expected_count", 0)

                print(f"\n{collection_name}/ ({doc_count} documents)")

                # Create parent document for this "collection"
                parent_doc_id = self._create_document(
                    collection_id,
                    collection_name,
                    f"# {collection_name}\n\nImported collection.",
                    parent_document_id=None
                )

                if parent_doc_id:
                    self.stats["documents_created"] += 1

                # Import documents under this parent
                self.import_collection(
                    collection_dir,
                    target_collection_id=collection_id,
                    parent_document_id=parent_doc_id
                )
        else:
            # Standard mode: one collection per folder
            for collection_dir in source_collections:
                metadata = self.load_collection_metadata(collection_dir)
                if not metadata:
                    continue

                collection_name = metadata.get("name", collection_dir.name)
                doc_count = metadata.get("expected_count", 0)

                print(f"\n{collection_name}/ ({doc_count} documents)")
                self.import_collection(collection_dir)

        # Print summary
        duration = time.time() - start_time
        print()
        print("=" * 60)
        print("SUMMARY")
        print("=" * 60)
        print(f"  Collections:  {self.stats['collections_created']} created, "
              f"{self.stats['collections_skipped']} skipped, "
              f"{self.stats['collections_errors']} errors")
        print(f"  Documents:   {self.stats['documents_created']} created, "
              f"{self.stats['documents_skipped']} skipped, "
              f"{self.stats['documents_errors']} errors")
        print(f"  Duration:     {duration:.1f} seconds")
        print("=" * 60)

        if self.errors:
            print()
            logger.warning(f"Encountered {len(self.errors)} errors during import")


def load_settings(settings_file: str = "settings.json") -> Dict:
    """Load settings from JSON file."""
    try:
        with open(settings_file, 'r') as f:
            return json.load(f)
    except FileNotFoundError:
        logger.error(f"Settings file not found: {settings_file}")
        logger.error("Create a settings.json file with your configuration")
        sys.exit(1)
    except json.JSONDecodeError as e:
        logger.error(f"Invalid JSON in settings file: {e}")
        sys.exit(1)


def parse_args() -> argparse.Namespace:
    """Parse command line arguments."""
    parser = argparse.ArgumentParser(
        description="Import markdown files into Outline wiki",
        formatter_class=argparse.RawDescriptionHelpFormatter,
        epilog="""
Examples:
  %(prog)s                      Import all collections from outline_export/
  %(prog)s --dry-run            Preview what would be imported
  %(prog)s --single             Import all into a single timestamped collection
  %(prog)s -d backup/           Import from custom directory
  %(prog)s --force              Overwrite existing collections
        """
    )
    parser.add_argument(
        '-s', '--single',
        action='store_true',
        help='Import all into single timestamped collection'
    )
    parser.add_argument(
        '-n', '--dry-run',
        action='store_true',
        help='Preview operations without making changes'
    )
    parser.add_argument(
        '-d', '--source',
        default=None,
        help='Source directory (default: outline_export)'
    )
    parser.add_argument(
        '-v', '--verbose',
        action='count',
        default=0,
        help='Increase verbosity (use -vv for debug)'
    )
    parser.add_argument(
        '-f', '--force',
        action='store_true',
        help='Overwrite existing collections (instead of skip)'
    )
    parser.add_argument(
        '--settings',
        default='settings.json',
        help='Path to settings file (default: settings.json)'
    )
    return parser.parse_args()


def main() -> None:
    """Main entry point."""
    args = parse_args()

    # Set log level based on verbosity
    if args.verbose >= 2:
        logger.setLevel(logging.DEBUG)
    elif args.verbose == 1:
        logger.setLevel(logging.INFO)

    # Load settings
    settings = load_settings(args.settings)

    source = settings.get("source", {})
    import_config = settings.get("import", {})
    advanced = settings.get("advanced", {})

    # Validate required settings
    if not source.get("url") or not source.get("token"):
        logger.error("Missing required settings: source.url and source.token")
        sys.exit(1)

    # Determine source directory
    source_dir = args.source or import_config.get("source_directory", "outline_export")

    # Create importer
    importer = OutlineImporter(
        base_url=source["url"],
        api_token=source["token"],
        source_dir=source_dir,
        dry_run=args.dry_run,
        single_mode=args.single,
        force=args.force,
        on_collection_exists=import_config.get("on_collection_exists", "skip"),
        on_document_exists=import_config.get("on_document_exists", "skip"),
        default_permission=import_config.get("default_permission", "read_write"),
        request_timeout=advanced.get("request_timeout", 30),
        retry_attempts=advanced.get("retry_attempts", 3),
        retry_delay=advanced.get("retry_delay", 1.0),
        rate_limit_delay=advanced.get("rate_limit_delay", 0.1)
    )

    # Run import
    try:
        importer.import_all()
    except KeyboardInterrupt:
        logger.warning("Import cancelled by user")
        sys.exit(1)
    except Exception as e:
        logger.exception(f"Import failed: {e}")
        sys.exit(1)


if __name__ == "__main__":
    main()