"""Plugin manager - main entry point for plugin system."""

from pathlib import Path
from typing import Dict, List, Optional
from flask import Flask
import logging

from .base import BasePlugin, PluginMeta
from .registry import PluginRegistry, PluginState
from .loader import PluginLoader
from .migrations import PluginMigrationManager

logger = logging.getLogger(__name__)

__all__ = [
    'PluginManager',
    'BasePlugin',
    'PluginMeta',
    'PluginRegistry',
    'PluginState',
    'plugin_manager'
]


class PluginManager:
    """
    Central manager for all plugin operations.

    Usage:
        plugin_manager = PluginManager()
        plugin_manager.init_app(app, db)

        # In CLI:
        plugin_manager.install_plugin('printers')
    """

    def __init__(self):
        self.registry: Optional[PluginRegistry] = None
        self.loader: Optional[PluginLoader] = None
        self.migration_manager: Optional[PluginMigrationManager] = None
        self._app: Optional[Flask] = None
        self._db = None

    def init_app(self, app: Flask, db) -> None:
        """Initialize plugin manager with Flask app."""
        self._app = app
        self._db = db

        # Setup paths
        instance_path = Path(app.instance_path)
        plugins_dir = Path(app.root_path).parent / 'plugins'

        # Initialize components
        self.registry = PluginRegistry(instance_path / 'plugins.json')
        self.loader = PluginLoader(plugins_dir, self.registry)
        self.migration_manager = PluginMigrationManager(
            plugins_dir,
            app.config.get('SQLALCHEMY_DATABASE_URI')
        )

        # Load enabled plugins
        self._load_enabled_plugins()

        # Store on app for access
        app.extensions['plugin_manager'] = self

    def _load_enabled_plugins(self) -> None:
        """Load and register all enabled plugins."""
        plugins = self.loader.load_enabled_plugins(self._app, self._db)

        for name, plugin in plugins.items():
            self._register_plugin_components(plugin)

    def upgrade_all_plugins(self) -> Dict[str, str]:
        """Run pending Alembic migrations for every loaded plugin.

        Returns {plugin_name: 'ok'|'no-migrations'|<error str>}. Skips
        plugins with no migrations/ directory. Use from the CLI
        (`flask plugin upgrade-all`) on a fresh deploy after the core
        schema is in place; existing deploys that still use db.create_all
        can ignore this and continue to do so.
        """
        results: Dict[str, str] = {}
        if not self.migration_manager:
            return results
        plugin_names = list(self.registry.list_installed().keys()) \
            if hasattr(self.registry, 'list_installed') else []
        if not plugin_names:
            # Fall back to whatever the loader found on disk.
            plugin_names = self.loader.discover_plugins()
        for name in plugin_names:
            if not self.migration_manager.has_pending_migrations(name):
                results[name] = 'no-migrations'
                continue
            try:
                ok = self.migration_manager.run_plugin_migrations(name)
                results[name] = 'ok' if ok else 'failed'
            except Exception as ex:
                results[name] = f'error: {ex}'
        return results

    def _register_plugin_components(self, plugin: BasePlugin) -> None:
        """Register plugin's blueprint, models, CLI commands, etc."""
        # Register blueprint
        blueprint = plugin.get_blueprint()
        if blueprint:
            self._app.register_blueprint(
                blueprint,
                url_prefix=plugin.meta.api_prefix
            )
            logger.debug(f"Registered blueprint: {plugin.meta.api_prefix}")

        # Register CLI commands
        for cmd in plugin.get_cli_commands():
            self._app.cli.add_command(cmd)

    def discover_available(self) -> List[Dict]:
        """
        Get list of all available plugins (installed or not).
        Returns list of plugin info dicts.
        """
        available = []

        for name in self.loader.discover_plugins():
            plugin_class = self.loader.load_plugin_class(name)
            if plugin_class:
                try:
                    temp = plugin_class()
                    meta = temp.meta
                    state = self.registry.get(name)

                    available.append({
                        'name': meta.name,
                        'version': meta.version,
                        'description': meta.description,
                        'author': meta.author,
                        'dependencies': meta.dependencies,
                        'installed': state is not None,
                        'enabled': state.enabled if state else False,
                        'installedat': state.installed_at if state else None
                    })
                except Exception as e:
                    logger.warning(f"Error inspecting plugin {name}: {e}")

        return available

    def install_plugin(self, name: str, run_migrations: bool = True) -> bool:
        """
        Install a plugin.

        Steps:
        1. Verify plugin exists
        2. Check dependencies
        3. Run database migrations
        4. Register in registry
        5. Call plugin's on_install hook
        """
        # Check if already installed
        if self.registry.is_installed(name):
            logger.warning(f"Plugin {name} is already installed")
            return False

        # Load plugin class
        plugin_class = self.loader.load_plugin_class(name)
        if not plugin_class:
            logger.error(f"Plugin {name} not found")
            return False

        temp_plugin = plugin_class()
        meta = temp_plugin.meta

        # Check dependencies
        for dep in meta.dependencies:
            if not self.registry.is_installed(dep):
                logger.error(
                    f"Plugin {name} requires {dep} to be installed first"
                )
                return False

        # Run migrations
        if run_migrations:
            success = self.migration_manager.run_plugin_migrations(name)
            if not success:
                logger.error(f"Failed to run migrations for {name}")
                return False

        # Register plugin
        self.registry.register(name, meta.version)

        # Load the plugin
        plugin = self.loader.load_plugin(name, self._app, self._db)
        if plugin:
            self._register_plugin_components(plugin)
            plugin.on_install(self._app)

        logger.info(f"Installed plugin: {name} v{meta.version}")
        return True

    def uninstall_plugin(self, name: str, remove_data: bool = False) -> bool:
        """
        Uninstall a plugin.

        Args:
            name: Plugin name
            remove_data: If True, run downgrade migrations to remove tables
        """
        if not self.registry.is_installed(name):
            logger.warning(f"Plugin {name} is not installed")
            return False

        # Check if other plugins depend on this one
        for other_name in self.registry.get_enabled_plugins():
            if other_name == name:
                continue
            other_plugin = self.loader.get_loaded_plugin(other_name)
            if other_plugin and name in other_plugin.meta.dependencies:
                logger.error(
                    f"Cannot uninstall {name}: {other_name} depends on it"
                )
                return False

        # Get plugin instance
        plugin = self.loader.get_loaded_plugin(name)

        # Call on_uninstall hook
        if plugin:
            plugin.on_uninstall(self._app)

        # Optionally remove data
        if remove_data:
            self.migration_manager.downgrade_plugin(name)

        # Unregister
        self.registry.unregister(name)

        logger.info(f"Uninstalled plugin: {name}")
        return True

    def enable_plugin(self, name: str) -> bool:
        """Enable a disabled plugin."""
        if not self.registry.is_installed(name):
            logger.error(f"Plugin {name} is not installed")
            return False

        if self.registry.is_enabled(name):
            logger.info(f"Plugin {name} is already enabled")
            return True

        # Check dependencies are enabled
        plugin_class = self.loader.load_plugin_class(name)
        if plugin_class:
            temp = plugin_class()
            for dep in temp.meta.dependencies:
                if not self.registry.is_enabled(dep):
                    logger.error(f"Cannot enable {name}: {dep} is not enabled")
                    return False

        self.registry.enable(name)

        # Load the plugin
        plugin = self.loader.load_plugin(name, self._app, self._db)
        if plugin:
            self._register_plugin_components(plugin)
            plugin.on_enable(self._app)

        logger.info(f"Enabled plugin: {name}")
        return True

    def disable_plugin(self, name: str) -> bool:
        """Disable an enabled plugin."""
        if not self.registry.is_enabled(name):
            logger.info(f"Plugin {name} is already disabled")
            return True

        # Check if other plugins depend on this one
        for other_name in self.registry.get_enabled_plugins():
            if other_name == name:
                continue
            other_plugin = self.loader.get_loaded_plugin(other_name)
            if other_plugin and name in other_plugin.meta.dependencies:
                logger.error(
                    f"Cannot disable {name}: {other_name} depends on it"
                )
                return False

        plugin = self.loader.get_loaded_plugin(name)
        if plugin:
            plugin.on_disable(self._app)

        self.registry.disable(name)
        logger.info(f"Disabled plugin: {name}")
        return True

    def get_plugin(self, name: str) -> Optional[BasePlugin]:
        """Get a loaded plugin instance."""
        return self.loader.get_loaded_plugin(name)

    def get_all_plugins(self) -> Dict[str, BasePlugin]:
        """Get all loaded plugins."""
        return self.loader.get_all_loaded()


# Global plugin manager instance
plugin_manager = PluginManager()
