import json
import uuid
from typing import Dict, List, Any, Optional, Callable, Union
from datetime import datetime
import re

from utils.logging import setup_logger
from utils.error_handling import handle_exceptions, AutomationError
from utils.storage import load_data, save_data

# Initialize logger
logger = setup_logger(__name__)

class Template:
    """Template for auto-applying patterns"""
    
    def __init__(self, name: str, template_type: str, content: Dict[str, Any], 
                 description: Optional[str] = None):
        """Initialize a template
        
        Args:
            name: Template name
            template_type: Type of template (task, note, goal, project, etc.)
            content: Template content
            description: Template description (optional)
        """
        self.id = str(uuid.uuid4())
        self.name = name
        self.description = description or ""
        self.template_type = template_type
        self.content = content
        self.created_at = datetime.now().isoformat()
        self.updated_at = self.created_at
        self.usage_count = 0
        self.last_used = None
        self.is_default = False
        self.tags = []
        self.variables = self._extract_variables()
    
    def _extract_variables(self) -> List[str]:
        """Extract variables from template content
        
        Returns:
            List of variable names
        """
        variables = []
        
        # Convert content to string for searching
        content_str = json.dumps(self.content)
        
        # Find all {{variable}} patterns
        pattern = r'\{\{([^\}]+)\}\}'
        matches = re.findall(pattern, content_str)
        
        # Add unique variables
        for match in matches:
            var_name = match.strip()
            if var_name and var_name not in variables:
                variables.append(var_name)
        
        return variables
    
    @handle_exceptions
    def apply(self, variables: Dict[str, Any] = None) -> Dict[str, Any]:
        """Apply template with variables
        
        Args:
            variables: Dictionary of variable values (optional)
            
        Returns:
            Applied template content
        """
        variables = variables or {}
        result = self._replace_variables(self.content, variables)
        
        # Update usage stats
        self.usage_count += 1
        self.last_used = datetime.now().isoformat()
        self.updated_at = self.last_used
        
        return result
    
    def _replace_variables(self, content: Any, variables: Dict[str, Any]) -> Any:
        """Replace variables in content recursively
        
        Args:
            content: Content to process
            variables: Dictionary of variable values
            
        Returns:
            Processed content
        """
        if isinstance(content, str):
            # Replace variables in string
            result = content
            for var_name, var_value in variables.items():
               pattern = r"\{\{\s*" + var_name + r"\s*\}\}"
                result = re.sub(pattern, str(var_value), result)
            return result
        
        elif isinstance(content, dict):
            # Process dictionary recursively
            result = {}
            for key, value in content.items():
                # Process both key and value
                new_key = self._replace_variables(key, variables)
                new_value = self._replace_variables(value, variables)
                result[new_key] = new_value
            return result
        
        elif isinstance(content, list):
            # Process list recursively
            result = []
            for item in content:
                result.append(self._replace_variables(item, variables))
            return result
        
        else:
            # Return other types unchanged
            return content
    
    @handle_exceptions
    def set_as_default(self, is_default: bool = True) -> None:
        """Set template as default
        
        Args:
            is_default: Whether template is default
        """
        self.is_default = is_default
        self.updated_at = datetime.now().isoformat()
    
    @handle_exceptions
    def add_tag(self, tag: str) -> None:
        """Add tag to template
        
        Args:
            tag: Tag to add
        """
        if tag not in self.tags:
            self.tags.append(tag)
            self.updated_at = datetime.now().isoformat()
    
    @handle_exceptions
    def remove_tag(self, tag: str) -> None:
        """Remove tag from template
        
        Args:
            tag: Tag to remove
        """
        if tag in self.tags:
            self.tags.remove(tag)
            self.updated_at = datetime.now().isoformat()
    
    @handle_exceptions
    def to_dict(self) -> Dict[str, Any]:
        """Convert template to dictionary
        
        Returns:
            Template as dictionary
        """
        return {
            "id": self.id,
            "name": self.name,
            "description": self.description,
            "template_type": self.template_type,
            "content": self.content,
            "created_at": self.created_at,
            "updated_at": self.updated_at,
            "usage_count": self.usage_count,
            "last_used": self.last_used,
            "is_default": self.is_default,
            "tags": self.tags,
            "variables": self.variables
        }
    
    @classmethod
    def from_dict(cls, data: Dict[str, Any]) -> 'Template':
        """Create template from dictionary
        
        Args:
            data: Template data
            
        Returns:
            Template instance
        """
        template = cls(
            data["name"], 
            data["template_type"], 
            data["content"], 
            data.get("description", "")
        )
        template.id = data["id"]
        template.created_at = data["created_at"]
        template.updated_at = data["updated_at"]
        template.usage_count = data.get("usage_count", 0)
        template.last_used = data.get("last_used")
        template.is_default = data.get("is_default", False)
        template.tags = data.get("tags", [])
        template.variables = data.get("variables", [])
        return template


class TemplateManager:
    """Manager for templates"""
    
    def __init__(self):
        """Initialize template manager"""
        self.templates = {}
        self.load_templates()
        self._ensure_default_templates()
    
    @handle_exceptions
    def load_templates(self) -> None:
        """Load templates from storage"""
        try:
            templates_data = load_data("templates", default=[])
            for template_data in templates_data:
                template = Template.from_dict(template_data)
                self.templates[template.id] = template
            logger.info(f"Loaded {len(self.templates)} templates")
        except Exception as e:
            logger.error(f"Failed to load templates: {str(e)}")
    
    @handle_exceptions
    def save_templates(self) -> None:
        """Save templates to storage"""
        try:
            templates_data = [template.to_dict() for template in self.templates.values()]
            save_data("templates", templates_data)
            logger.info(f"Saved {len(self.templates)} templates")
        except Exception as e:
            logger.error(f"Failed to save templates: {str(e)}")
    
    def _ensure_default_templates(self) -> None:
        """Ensure default templates exist"""
        # Check if we need to create default templates
        if not self.get_templates_by_type("task"):
            self._create_default_task_template()
        
        if not self.get_templates_by_type("note"):
            self._create_default_note_template()
        
        if not self.get_templates_by_type("goal"):
            self._create_default_goal_template()
        
        if not self.get_templates_by_type("project"):
            self._create_default_project_template()
    
    def _create_default_task_template(self) -> None:
        """Create default task template"""
        content = {
            "title": "{{title}}",
            "description": "{{description}}",
            "status": "pending",
            "priority": "{{priority|normal}}",
            "due_date": "{{due_date}}",
            "tags": ["{{tag}}"],
            "category": "{{category|general}}"
        }
        
        template = Template("Default Task", "task", content, "Default template for tasks")
        template.set_as_default(True)
        template.add_tag("default")
        
        self.templates[template.id] = template
        self.save_templates()
    
    def _create_default_note_template(self) -> None:
        """Create default note template"""
        content = {
            "title": "{{title}}",
            "content": "{{content}}",
            "tags": ["{{tag}}"],
            "category": "{{category|general}}"
        }
        
        template = Template("Default Note", "note", content, "Default template for notes")
        template.set_as_default(True)
        template.add_tag("default")
        
        self.templates[template.id] = template
        self.save_templates()
    
    def _create_default_goal_template(self) -> None:
        """Create default goal template"""
        content = {
            "title": "{{title}}",
            "description": "{{description}}",
            "target_date": "{{target_date}}",
            "status": "in_progress",
            "progress": 0,
            "tags": ["{{tag}}"],
            "category": "{{category|personal}}"
        }
        
        template = Template("Default Goal", "goal", content, "Default template for goals")
        template.set_as_default(True)
        template.add_tag("default")
        
        self.templates[template.id] = template
        self.save_templates()
    
    def _create_default_project_template(self) -> None:
        """Create default project template"""
        content = {
            "title": "{{title}}",
            "description": "{{description}}",
            "start_date": "{{start_date}}",
            "end_date": "{{end_date}}",
            "status": "planning",
            "progress": 0,
            "tags": ["{{tag}}"],
            "category": "{{category|work}}",
            "tasks": []
        }
        
        template = Template("Default Project", "project", content, "Default template for projects")
        template.set_as_default(True)
        template.add_tag("default")
        
        self.templates[template.id] = template
        self.save_templates()
    
    @handle_exceptions
    def create_template(self, name: str, template_type: str, content: Dict[str, Any], 
                       description: Optional[str] = None) -> Template:
        """Create a new template
        
        Args:
            name: Template name
            template_type: Type of template
            content: Template content
            description: Template description (optional)
            
        Returns:
            Created template
        """
        template = Template(name, template_type, content, description)
        self.templates[template.id] = template
        self.save_templates()
        return template
    
    @handle_exceptions
    def get_template(self, template_id: str) -> Optional[Template]:
        """Get template by ID
        
        Args:
            template_id: Template ID
            
        Returns:
            Template if found, None otherwise
        """
        return self.templates.get(template_id)
    
    @handle_exceptions
    def update_template(self, template: Template) -> None:
        """Update template
        
        Args:
            template: Template to update
        """
        if template.id in self.templates:
            template.updated_at = datetime.now().isoformat()
            self.templates[template.id] = template
            self.save_templates()
        else:
            raise AutomationError(f"Template not found: {template.id}")
    
    @handle_exceptions
    def delete_template(self, template_id: str) -> None:
        """Delete template
        
        Args:
            template_id: Template ID
        """
        if template_id in self.templates:
            del self.templates[template_id]
            self.save_templates()
        else:
            raise AutomationError(f"Template not found: {template_id}")
    
    @handle_exceptions
    def get_all_templates(self) -> List[Template]:
        """Get all templates
        
        Returns:
            List of all templates
        """
        return list(self.templates.values())
    
    @handle_exceptions
    def get_templates_by_type(self, template_type: str) -> List[Template]:
        """Get templates by type
        
        Args:
            template_type: Template type
            
        Returns:
            List of templates of the specified type
        """
        return [
            template for template in self.templates.values()
            if template.template_type == template_type
        ]
    
    @handle_exceptions
    def get_templates_by_tag(self, tag: str) -> List[Template]:
        """Get templates by tag
        
        Args:
            tag: Tag to filter by
            
        Returns:
            List of templates with the specified tag
        """
        return [
            template for template in self.templates.values()
            if tag in template.tags
        ]
    
    @handle_exceptions
    def get_default_template(self, template_type: str) -> Optional[Template]:
        """Get default template for a type
        
        Args:
            template_type: Template type
            
        Returns:
            Default template if found, None otherwise
        """
        templates = self.get_templates_by_type(template_type)
        for template in templates:
            if template.is_default:
                return template
        
        # If no default template found, return the first one
        return templates[0] if templates else None
    
    @handle_exceptions
    def set_default_template(self, template_id: str) -> None:
        """Set a template as default for its type
        
        Args:
            template_id: Template ID
        """
        template = self.get_template(template_id)
        if not template:
            raise AutomationError(f"Template not found: {template_id}")
        
        # Clear default flag for all templates of this type
        for t in self.get_templates_by_type(template.template_type):
            if t.is_default:
                t.set_as_default(False)
                self.update_template(t)
        
        # Set this template as default
        template.set_as_default(True)
        self.update_template(template)
    
    @handle_exceptions
    def apply_template(self, template_id: str, variables: Dict[str, Any] = None) -> Dict[str, Any]:
        """Apply a template with variables
        
        Args:
            template_id: Template ID
            variables: Dictionary of variable values (optional)
            
        Returns:
            Applied template content
        """
        template = self.get_template(template_id)
        if not template:
            raise AutomationError(f"Template not found: {template_id}")
        
        result = template.apply(variables)
        self.update_template(template)  # Update usage stats
        return result
    
    @handle_exceptions
    def apply_default_template(self, template_type: str, variables: Dict[str, Any] = None) -> Dict[str, Any]:
        """Apply the default template for a type
        
        Args:
            template_type: Template type
            variables: Dictionary of variable values (optional)
            
        Returns:
            Applied template content
        """
        template = self.get_default_template(template_type)
        if not template:
            raise AutomationError(f"No template found for type: {template_type}")
        
        return self.apply_template(template.id, variables)
    
    @handle_exceptions
    def duplicate_template(self, template_id: str, new_name: Optional[str] = None) -> Template:
        """Duplicate a template
        
        Args:
            template_id: Template ID
            new_name: New template name (optional)
            
        Returns:
            Duplicated template
        """
        template = self.get_template(template_id)
        if not template:
            raise AutomationError(f"Template not found: {template_id}")
        
        # Create new name if not provided
        if not new_name:
            new_name = f"Copy of {template.name}"
        
        # Create new template
        new_template = Template(
            new_name,
            template.template_type,
            template.content.copy(),
            template.description
        )
        
        # Copy tags
        for tag in template.tags:
            new_template.add_tag(tag)
        
        # Add to templates
        self.templates[new_template.id] = new_template
        self.save_templates()
        
        return new_template
    
    @handle_exceptions
    def import_templates(self, templates_data: List[Dict[str, Any]], 
                        overwrite_existing: bool = False) -> int:
        """Import templates from data
        
        Args:
            templates_data: List of template data
            overwrite_existing: Whether to overwrite existing templates
            
        Returns:
            Number of templates imported
        """
        imported_count = 0
        
        for template_data in templates_data:
            try:
                template = Template.from_dict(template_data)
                
                # Check if template with same ID exists
                if template.id in self.templates:
                    if overwrite_existing:
                        self.templates[template.id] = template
                        imported_count += 1
                else:
                    self.templates[template.id] = template
                    imported_count += 1
            except Exception as e:
                logger.error(f"Failed to import template: {str(e)}")
        
        if imported_count > 0:
            self.save_templates()
        
        return imported_count
    
    @handle_exceptions
    def export_templates(self, template_ids: Optional[List[str]] = None) -> List[Dict[str, Any]]:
        """Export templates to data
        
        Args:
            template_ids: List of template IDs to export (optional, exports all if None)
            
        Returns:
            List of template data
        """
        if template_ids:
            # Export specific templates
            templates = []
            for template_id in template_ids:
                template = self.get_template(template_id)
                if template:
                    templates.append(template)
        else:
            # Export all templates
            templates = self.get_all_templates()
        
        return [template.to_dict() for template in templates]


# Create a global instance of the template manager
template_manager = TemplateManager()