from __future__ import annotations

import logging
from pathlib import Path

import yaml

from .config import ConfigManager
from .exceptions import DuplicateTemplateError, LibraryError, TemplateDraftError, TemplateNotFoundError

logger = logging.getLogger(__name__)

# Qualified ID format: "template_id.library_name"
QUALIFIED_ID_PARTS = 2


class Library:
    """Represents a single library with a specific path."""

    def __init__(self, name: str, path: Path, priority: int = 0, library_type: str = "git") -> None:
        """Initialize a library instance.

        Args:
          name: Display name for the library
          path: Path to the library directory
          priority: Priority for library lookup (higher = checked first)
          library_type: Type of library ("git" or "static")
        """
        if library_type not in ("git", "static"):
            raise ValueError(f"Invalid library type: {library_type}. Must be 'git' or 'static'.")

        self.name = name
        self.path = path
        self.priority = priority  # Higher priority = checked first
        self.library_type = library_type

    def _is_template_draft(self, template_path: Path) -> bool:
        """Check if a template is marked as draft."""
        # Find the template file
        for filename in ("template.yaml", "template.yml"):
            template_file = template_path / filename
            if template_file.exists():
                break
        else:
            return False

        try:
            with template_file.open(encoding="utf-8") as f:
                docs = [doc for doc in yaml.safe_load_all(f) if doc]
                return docs[0].get("metadata", {}).get("draft", False) if docs else False
        except (yaml.YAMLError, OSError) as e:
            logger.warning(f"Error checking draft status for {template_path}: {e}")
            return False

    def find_by_id(self, module_name: str, template_id: str) -> tuple[Path, str]:
        """Find a template by its ID in this library for generation/show operations.

        Note: Draft templates are intentionally excluded from this method.
        They are visible in list/search commands (via find()) but cannot be
        used for generation as they are work-in-progress.

        Args:
            module_name: The module name (e.g., 'compose', 'terraform')
            template_id: The template ID to find

        Returns:
            Path to the template directory if found and not draft

        Raises:
            TemplateDraftError: If the template exists but is marked as draft
            TemplateNotFoundError: If the template ID is not found in this library
        """
        logger.debug(f"Looking for template '{template_id}' in module '{module_name}' in library '{self.name}'")

        # Build the path to the specific template directory
        template_path = self.path / module_name / template_id

        # Check if template directory exists with a template file
        has_template = template_path.is_dir() and any(
            (template_path / f).exists() for f in ("template.yaml", "template.yml")
        )

        # Template not found at all
        if not has_template:
            raise TemplateNotFoundError(template_id, module_name)

        # Template exists but is in draft mode
        if self._is_template_draft(template_path):
            raise TemplateDraftError(template_id, module_name)

        logger.debug(f"Found template '{template_id}' at: {template_path}")
        return template_path, self.name

    def find(self, module_name: str, sort_results: bool = False) -> list[tuple[Path, str]]:
        """Find templates in this library for a specific module.

        Includes all templates (both published and draft).

        Args:
            module_name: The module name (e.g., 'compose', 'terraform')
            sort_results: Whether to return results sorted alphabetically

        Returns:
            List of Path objects representing template directories (including drafts)

        Raises:
            FileNotFoundError: If the module directory is not found in this library
        """
        logger.debug(f"Looking for templates in module '{module_name}' in library '{self.name}'")

        # Build the path to the module directory
        module_path = self.path / module_name

        # Check if the module directory exists
        if not module_path.is_dir():
            raise LibraryError(f"Module '{module_name}' not found in library '{self.name}'")

        # Track seen IDs to detect duplicates within this library
        seen_ids = {}
        template_dirs = []
        try:
            for item in module_path.iterdir():
                has_template = item.is_dir() and any((item / f).exists() for f in ("template.yaml", "template.yml"))
                if has_template:
                    template_id = item.name

                    # Check for duplicate within same library
                    if template_id in seen_ids:
                        raise DuplicateTemplateError(template_id, self.name)

                    seen_ids[template_id] = True
                    template_dirs.append((item, self.name))
        except PermissionError as e:
            raise LibraryError(
                f"Permission denied accessing module '{module_name}' in library '{self.name}': {e}"
            ) from e

        # Sort if requested
        if sort_results:
            template_dirs.sort(key=lambda x: x[0].name.lower())

        logger.debug(f"Found {len(template_dirs)} templates in module '{module_name}'")
        return template_dirs


class LibraryManager:
    """Manages multiple libraries and provides methods to find templates."""

    def __init__(self) -> None:
        """Initialize LibraryManager with git-based libraries from config."""
        self.config = ConfigManager()
        self.libraries = self._load_libraries_from_config()

    def _resolve_git_library_path(self, name: str, lib_config: dict, libraries_path: Path) -> Path:
        """Resolve path for a git-based library."""
        directory = lib_config.get("directory", ".")
        library_base = libraries_path / name
        if directory and directory != ".":
            return library_base / directory
        return library_base

    def _resolve_static_library_path(self, name: str, lib_config: dict) -> Path | None:
        """Resolve path for a static library."""
        path_str = lib_config.get("path")
        if not path_str:
            logger.warning(f"Static library '{name}' has no path configured")
            return None

        library_path = Path(path_str).expanduser()
        if not library_path.is_absolute():
            library_path = (self.config.config_path.parent / library_path).resolve()
        return library_path

    def _warn_missing_library(self, name: str, library_path: Path, lib_type: str) -> None:
        """Log warning about missing library."""
        if lib_type == "git":
            logger.warning(
                f"Library '{name}' not found at {library_path}. Run 'boilerplates repo update' to sync libraries."
            )
        else:
            logger.warning(f"Static library '{name}' not found at {library_path}")

    def _load_libraries_from_config(self) -> list[Library]:
        """Load libraries from configuration.

        Returns:
            List of Library instances
        """
        libraries = []
        libraries_path = self.config.get_libraries_path()
        library_configs = self.config.get_libraries()

        for i, lib_config in enumerate(library_configs):
            # Skip disabled libraries
            if not lib_config.get("enabled", True):
                logger.debug(f"Skipping disabled library: {lib_config.get('name')}")
                continue

            name = lib_config.get("name")
            lib_type = lib_config.get("type", "git")

            # Resolve library path based on type
            if lib_type == "git":
                library_path = self._resolve_git_library_path(name, lib_config, libraries_path)
            elif lib_type == "static":
                library_path = self._resolve_static_library_path(name, lib_config)
                if not library_path:
                    continue
            else:
                logger.warning(f"Unknown library type '{lib_type}' for library '{name}'")
                continue

            # Check if library path exists
            if not library_path.exists():
                self._warn_missing_library(name, library_path, lib_type)
                continue

            # Create Library instance with priority based on order
            priority = len(library_configs) - i
            libraries.append(
                Library(
                    name=name,
                    path=library_path,
                    priority=priority,
                    library_type=lib_type,
                )
            )
            logger.debug(f"Loaded {lib_type} library '{name}' from {library_path} with priority {priority}")

        if not libraries:
            logger.warning("No libraries loaded. Run 'boilerplates repo update' to sync libraries.")

        return libraries

    def find_by_id(self, module_name: str, template_id: str) -> tuple[Path, str] | None:
        """Find a template by its ID across all libraries.

        Supports both simple IDs and qualified IDs (template.library format).

        Args:
            module_name: The module name (e.g., 'compose', 'terraform')
            template_id: The template ID to find (simple or qualified)

        Returns:
            Tuple of (template_path, library_name) if found, None otherwise
        """
        logger.debug(f"Searching for template '{template_id}' in module '{module_name}' across all libraries")

        # Check if this is a qualified ID (contains '.')
        if "." in template_id:
            parts = template_id.rsplit(".", 1)
            if len(parts) == QUALIFIED_ID_PARTS:
                base_id, requested_lib = parts
                logger.debug(f"Parsing qualified ID: base='{base_id}', library='{requested_lib}'")

                # Try to find in the specific library
                for library in self.libraries:
                    if library.name == requested_lib:
                        try:
                            template_path, lib_name = library.find_by_id(module_name, base_id)
                            logger.debug(f"Found template '{base_id}' in library '{requested_lib}'")
                            return template_path, lib_name
                        except (TemplateNotFoundError, TemplateDraftError):
                            logger.debug(f"Template '{base_id}' not found in library '{requested_lib}'")
                            return None

                logger.debug(f"Library '{requested_lib}' not found")
                return None

        # Simple ID - search by priority
        for library in sorted(self.libraries, key=lambda x: x.priority, reverse=True):
            try:
                template_path, lib_name = library.find_by_id(module_name, template_id)
                logger.debug(f"Found template '{template_id}' in library '{library.name}'")
                return template_path, lib_name
            except TemplateNotFoundError:
                # Continue searching in next library
                continue
            except TemplateDraftError:
                # Draft error should propagate immediately (don't search other libraries)
                raise

        logger.debug(f"Template '{template_id}' not found in any library")
        return None

    def find(self, module_name: str, sort_results: bool = False) -> list[tuple[Path, str, bool]]:
        """Find templates across all libraries for a specific module.

        Handles duplicates by qualifying IDs with library names when needed.

        Args:
            module_name: The module name (e.g., 'compose', 'terraform')
            sort_results: Whether to return results sorted alphabetically

        Returns:
            List of tuples (template_path, library_name, needs_qualification)
            where needs_qualification is True if the template ID appears in multiple libraries
        """
        logger.debug(f"Searching for templates in module '{module_name}' across all libraries")

        all_templates = []

        # Collect templates from all libraries
        for library in sorted(self.libraries, key=lambda x: x.priority, reverse=True):
            try:
                templates = library.find(module_name, sort_results=False)
                all_templates.extend(templates)
                logger.debug(f"Found {len(templates)} templates in library '{library.name}'")
            except (LibraryError, DuplicateTemplateError) as e:
                # DuplicateTemplateError from library.find() should propagate up
                if isinstance(e, DuplicateTemplateError):
                    raise
                logger.debug(f"Module '{module_name}' not found in library '{library.name}'")
                continue

        # Track template IDs and their libraries to detect cross-library duplicates
        id_to_occurrences = {}
        for template_path, library_name in all_templates:
            template_id = template_path.name
            if template_id not in id_to_occurrences:
                id_to_occurrences[template_id] = []
            id_to_occurrences[template_id].append((template_path, library_name))

        # Build result with qualification markers for duplicates
        result = []
        for template_id, occurrences in id_to_occurrences.items():
            if len(occurrences) > 1:
                # Duplicate across libraries - mark for qualified IDs
                lib_names = ", ".join(lib for _, lib in occurrences)
                logger.info(f"Template '{template_id}' found in multiple libraries: {lib_names}. Using qualified IDs.")
                for template_path, library_name in occurrences:
                    # Mark that this ID needs qualification
                    result.append((template_path, library_name, True))
            else:
                # Unique template - no qualification needed
                template_path, library_name = occurrences[0]
                result.append((template_path, library_name, False))

        # Sort if requested
        if sort_results:
            result.sort(key=lambda x: x[0].name.lower())

        logger.debug(f"Found {len(result)} templates total")
        return result