"""
OMIRL Shared Validation and Configuration

This module provides configuration-based validation for OMIRL parameters.
It loads validation rules and parameter definitions from YAML files,
making the system more maintainable and flexible.
"""

import yaml
from typing import List, Dict, Set, Optional, Tuple, Any
from pathlib import Path
import difflib


class OMIRLValidator:
    """
    Configuration-based validator for OMIRL parameters
    
    Loads validation rules and parameter definitions from YAML files,
    providing flexible validation with auto-correction and suggestions.
    """
    
    def __init__(self, config_dir: Optional[Path] = None):
        if config_dir is None:
            # Default to config directory relative to this file
            config_dir = Path(__file__).parent.parent / "config"
        
        self.config_dir = Path(config_dir)
        self._load_configurations()
    
    def _load_configurations(self):
        """Load all YAML configuration files"""
        try:
            # Load parameter definitions (OMIRL-specific)
            with open(self.config_dir / "parameters.yaml", 'r', encoding='utf-8') as f:
                self.parameters = yaml.safe_load(f)
            
            # Load geographic data from global configuration
            self._load_geography_config()
            
            # Load mode/task combinations
            with open(self.config_dir / "tasks.yaml", 'r', encoding='utf-8') as f:
                self.mode_tasks = yaml.safe_load(f)
            
            # Load validation rules
            with open(self.config_dir / "validation_rules.yaml", 'r', encoding='utf-8') as f:
                self.validation_rules = yaml.safe_load(f)
                
        except FileNotFoundError as e:
            raise RuntimeError(f"OMIRL configuration file not found: {e}")
        except yaml.YAMLError as e:
            raise RuntimeError(f"Error parsing OMIRL configuration: {e}")
    
    def _load_geography_config(self):
        """Load geographic data from the global configuration"""
        try:
            # Look for global geography configuration
            global_config_path = Path(__file__).parent.parent.parent.parent / "agent" / "config" / "geography.yaml"
            
            if global_config_path.exists():
                with open(global_config_path, 'r', encoding='utf-8') as f:
                    geography_config = yaml.safe_load(f)
                
                # Extract Liguria region data
                liguria_data = geography_config.get("regions", {}).get("liguria", {})
                
                # Store geography data for comune validation
                self._geography_data = liguria_data
                
                # Add provinces to parameters for backward compatibility
                if "provinces" in liguria_data:
                    self.parameters["provinces"] = liguria_data["provinces"]
                
                # Add alert zones to parameters for backward compatibility
                if "alert_zones" in liguria_data:
                    # Convert alert zones format to match expected format
                    alert_zones = liguria_data["alert_zones"]
                    if isinstance(alert_zones, dict) and "zones" in alert_zones:
                        self.parameters["alert_zones"] = alert_zones["zones"]
                    else:
                        self.parameters["alert_zones"] = alert_zones
                        
            else:
                raise RuntimeError(f"Global geography configuration not found at {global_config_path}")
                
        except Exception as e:
            raise RuntimeError(f"Error loading geography configuration: {e}")
    
    def validate_sensor_type(self, sensor_type: str) -> Tuple[bool, Optional[str], List[str]]:
        """
        Validate sensor type parameter
        
        Returns:
            Tuple of (is_valid, corrected_value, suggestions)
        """
        if not sensor_type:
            return True, None, []
        
        valid_types = self.parameters['sensor_types']
        
        # Exact match (case insensitive if configured)
        if self.validation_rules['rules']['sensor_type']['case_sensitive']:
            if sensor_type in valid_types:
                return True, sensor_type, []
        else:
            # Case insensitive matching
            for valid_type in valid_types:
                if sensor_type.lower() == valid_type.lower():
                    return True, valid_type, []
        
        # Generate suggestions using fuzzy matching
        suggestions = []
        if self.validation_rules['validation_settings']['provide_suggestions']:
            suggestions = self._get_suggestions(sensor_type, valid_types)
        
        return False, None, suggestions
    
    def validate_provincia(self, provincia: str, task: str = None) -> Tuple[bool, Optional[str], List[str]]:
        """
        Validate and normalize province parameter with task-specific formatting
        
        Args:
            provincia: Province name or code to validate
            task: Task name for task-specific formatting (valori_stazioni, massimi_precipitazione, etc.)
        
        Returns:
            Tuple of (is_valid, normalized_value, suggestions)
        """
        if not provincia:
            return True, None, []
        
        provincia_config = self.parameters['provinces']
        rules = self.validation_rules['rules']['provincia']
        
        # Determine target format based on task
        target_format = "codes"  # Default
        if task and 'task_specific_formats' in rules:
            target_format = rules['task_specific_formats'].get(task, target_format)
        elif rules.get('auto_convert_to_codes', True):
            target_format = "codes"
        
        # For case-insensitive matching, but preserve proper format for return
        provincia_check = provincia if rules['case_sensitive'] else provincia.upper()
        
        # Check if it's already a valid code
        if rules['allow_codes'] and provincia_check in provincia_config['codes']:
            if target_format == "codes":
                return True, provincia_check, []
            else:  # target_format == "names"
                # Convert code to name (return proper case name)
                code_to_name = {v: k for k, v in provincia_config['name_to_code_mapping'].items()}
                if provincia_check in code_to_name:
                    return True, code_to_name[provincia_check], []
        
        # Check if it's a full name - handle case-insensitive matching
        if rules['allow_full_names']:
            # For names, we need to find the exact match regardless of case
            name_mapping = provincia_config['name_to_code_mapping']
            
            # Find matching name (case-insensitive)
            matched_name = None
            for valid_name in name_mapping.keys():
                if (rules['case_sensitive'] and provincia == valid_name) or \
                   (not rules['case_sensitive'] and provincia.upper() == valid_name.upper()):
                    matched_name = valid_name
                    break
            
            if matched_name:
                if target_format == "names":
                    # Return the properly formatted name from configuration
                    return True, matched_name, []
                else:  # target_format == "codes"
                    code = name_mapping[matched_name]
                    return True, code, []
        
        # Generate suggestions
        suggestions = []
        if self.validation_rules['validation_settings']['provide_suggestions']:
            all_valid = provincia_config['codes'] + provincia_config['full_names']
            suggestions = self._get_suggestions(provincia, all_valid)
        
        return False, None, suggestions
    
    def validate_zona(self, zona: str) -> Tuple[bool, Optional[str], List[str]]:
        """Validate alert zone parameter"""
        if not zona:
            return True, None, []
        
        valid_zones = self.parameters['alert_zones']
        rules = self.validation_rules['rules']['zona']
        
        zona_check = zona if rules['case_sensitive'] else zona.upper()
        
        if zona_check in valid_zones:
            return True, zona_check, []
        
        suggestions = []
        if self.validation_rules['validation_settings']['provide_suggestions']:
            suggestions = self._get_suggestions(zona, valid_zones)
        
        return False, None, suggestions
    
    def validate_comune(self, comune: str, provincia: str = None) -> Tuple[bool, Optional[str], Optional[str], List[str]]:
        """
        Validate comune parameter and optionally infer province
        
        Args:
            comune: Municipality name to validate
            provincia: Optional province to validate against
        
        Returns:
            Tuple of (is_valid, normalized_comune, inferred_provincia, suggestions)
        """
        if not comune:
            return True, None, None, []
        
        rules = self.validation_rules['rules']['comune']
        
        # Get municipality data from global geography (loaded via _load_geography_config)
        comuni_by_province = getattr(self, '_comuni_by_province', {})
        if not comuni_by_province:
            # Extract from parameters if not cached
            # This would contain the loaded geography data
            comuni_by_province = {}
        
        # Build municipality lookup if not already built
        if not hasattr(self, '_municipality_to_province'):
            self._municipality_to_province = {}
            # Extract from the loaded geography data in parameters
            # The geography config loading should populate this
            pass
        
        # Normalize case for comparison
        comune_check = comune if rules['case_sensitive'] else comune.title()
        
        # Look for the municipality across all provinces
        found_province = None
        normalized_comune = None
        
        # Search in loaded geography data
        if hasattr(self, '_geography_data'):
            liguria_data = self._geography_data
            comuni_by_province = liguria_data.get('comuni_by_province', {})
            
            for prov_name, comuni_list in comuni_by_province.items():
                if isinstance(comuni_list, list):
                    for comune_name in comuni_list:
                        if (rules['case_sensitive'] and comune == comune_name) or \
                           (not rules['case_sensitive'] and comune.upper() == comune_name.upper()):
                            found_province = prov_name
                            normalized_comune = comune_name
                            break
                if found_province:
                    break
        
        # If provincia is specified, validate the comune exists in that province
        if provincia and rules.get('require_provincia_match', False):
            if found_province and found_province.upper() != provincia.upper():
                return False, None, None, [f"Il comune '{comune}' non si trova nella provincia '{provincia}' ma in '{found_province}'"]
        
        if found_province:
            return True, normalized_comune, found_province, []
        
        # Generate suggestions if not found
        suggestions = []
        if self.validation_rules['validation_settings']['provide_suggestions']:
            # Collect all municipality names for suggestions
            all_comuni = []
            if hasattr(self, '_geography_data'):
                liguria_data = self._geography_data
                comuni_by_province = liguria_data.get('comuni_by_province', {})
                for comuni_list in comuni_by_province.values():
                    if isinstance(comuni_list, list):
                        all_comuni.extend(comuni_list)
            
            suggestions = self._get_suggestions(comune, all_comuni)
        
        return False, None, None, suggestions
    
    def validate_periodo(self, periodo: str) -> Tuple[bool, Optional[str], List[str]]:
        """Validate time period parameter"""
        if not periodo:
            return True, None, []
        
        valid_periods = self.parameters['time_periods']
        rules = self.validation_rules['rules']['periodo']
        
        periodo_check = periodo if rules['case_sensitive'] else periodo.lower()
        
        # Check exact match
        for valid_period in valid_periods:
            if periodo_check == (valid_period if rules['case_sensitive'] else valid_period.lower()):
                return True, valid_period, []
        
        suggestions = []
        if self.validation_rules['validation_settings']['provide_suggestions']:
            suggestions = self._get_suggestions(periodo, valid_periods)
        
        return False, None, suggestions
    
    # DEPRECATED: validate_mode_task_combination - mode parameter removed
    # def validate_mode_task_combination(self, mode: str, task: str) -> Tuple[bool, List[str]]:
    #     """
    #     Validate that mode and task combination is supported
    #     
    #     Returns:
    #         Tuple of (is_valid, valid_tasks_for_mode)
    #     """
    #     valid_combinations = self.mode_tasks['valid_combinations']
    #     
    #     if mode not in valid_combinations:
    #         return False, []
    #     
    #     valid_tasks = valid_combinations[mode]
    #     return task in valid_tasks, valid_tasks
    
    def validate_variabile_climatica(self, variabile: str) -> Tuple[bool, Optional[str], List[str]]:
        """Validate climate variable parameter"""
        if not variabile:
            return True, None, []
        
        valid_variables = self.parameters['climate_variables']
        
        # Case insensitive matching
        for valid_var in valid_variables:
            if variabile.lower() == valid_var.lower():
                return True, valid_var, []
        
        suggestions = []
        if self.validation_rules['validation_settings']['provide_suggestions']:
            suggestions = self._get_suggestions(variabile, valid_variables)
        
        return False, None, suggestions
    
    def validate_satellite_area(self, area: str) -> Tuple[bool, Optional[str], List[str]]:
        """Validate satellite area parameter"""
        if not area:
            return True, None, []
        
        valid_areas = self.parameters['satellite_areas']
        
        # Case insensitive matching
        for valid_area in valid_areas:
            if area.lower() == valid_area.lower():
                return True, valid_area, []
        
        suggestions = []
        if self.validation_rules['validation_settings']['provide_suggestions']:
            suggestions = self._get_suggestions(area, valid_areas)
        
        return False, None, suggestions
    
    def get_task_url(self, mode: str, task: str) -> Optional[str]:
        """Get the URL for a specific mode/task combination"""
        task_urls = self.parameters.get('task_urls', {})
        return task_urls.get(mode, {}).get(task)
    
    def get_task_requirements(self, task: str) -> Dict[str, Any]:
        """Get requirements for a specific task"""
        return self.mode_tasks.get('task_requirements', {}).get(task, {})
    
    def validate_complete_request(self, task: str, filters: Dict[str, Any]) -> Tuple[bool, Dict[str, Any], List[str]]:
        """
        Validate a complete OMIRL request
        
        Returns:
            Tuple of (is_valid, corrected_filters, error_messages)
        """
        errors = []
        corrected_filters = filters.copy()
        
        # Validate task exists (no mode validation needed)
        valid_tasks = self.mode_tasks.get('valid_tasks', [])
        
        if task not in valid_tasks:
            errors.append(f"Invalid task '{task}'. Valid tasks: {valid_tasks}")
            return False, corrected_filters, errors
        
        # Validate filters are allowed for this task
        task_requirements = self.get_task_requirements(task)
        allowed_filters = set(task_requirements.get('required_filters', []) + task_requirements.get('optional_filters', []))
        
        # Remove filters that are not allowed for this task
        for filter_name in list(corrected_filters.keys()):
            if filter_name not in allowed_filters:
                print(f"⚠️  Removing unsupported filter '{filter_name}' for task '{task}'. Allowed filters: {list(allowed_filters)}")
                del corrected_filters[filter_name]
        
        # Validate individual filters
        validation_methods = {
            'tipo_sensore': self.validate_sensor_type,
            'zona': self.validate_zona,
            'periodo': self.validate_periodo,
            'variabile_climatica': self.validate_variabile_climatica
        }
        
        for filter_name, filter_value in filters.items():
            if filter_name in validation_methods and filter_value:
                is_valid, corrected_value, suggestions = validation_methods[filter_name](filter_value)
                
                if not is_valid:
                    error_msg = f"Invalid {filter_name}: '{filter_value}'"
                    if suggestions:
                        error_msg += f". Suggestions: {', '.join(suggestions[:3])}"
                    errors.append(error_msg)
                elif corrected_value and corrected_value != filter_value:
                    # Auto-correction applied
                    corrected_filters[filter_name] = corrected_value
            elif filter_name == 'provincia' and filter_value:
                # Special handling for provincia with task-specific formatting
                is_valid, corrected_value, suggestions = self.validate_provincia(filter_value, task)
                
                if not is_valid:
                    error_msg = f"Invalid provincia: '{filter_value}'"
                    if suggestions:
                        error_msg += f". Suggestions: {', '.join(suggestions[:3])}"
                    errors.append(error_msg)
                elif corrected_value and corrected_value != filter_value:
                    # Auto-correction applied
                    corrected_filters[filter_name] = corrected_value
        
        return len(errors) == 0, corrected_filters, errors
    
    def _get_suggestions(self, invalid_value: str, valid_options: List[str]) -> List[str]:
        """Generate suggestions using fuzzy string matching"""
        threshold = self.validation_rules['suggestion_settings']['similarity_threshold']
        max_suggestions = self.validation_rules['suggestion_settings']['max_suggestions']
        
        suggestions = difflib.get_close_matches(
            invalid_value, 
            valid_options, 
            n=max_suggestions, 
            cutoff=threshold
        )
        
        return suggestions
    
    def get_valid_tasks(self) -> List[str]:
        """Get list of valid tasks"""
        return self.parameters.get('valid_tasks', []).copy()
    
    def get_task_default(self, task: str, parameter: str) -> Optional[str]:
        """Get default value for a task parameter"""
        defaults = self.parameters.get('defaults', {})
        task_defaults = defaults.get(task, {})
        return task_defaults.get(parameter)
    
    def get_task_url(self, task: str, mode: str = "tables") -> Optional[str]:
        """Get the URL for a specific task and mode"""
        task_urls = self.parameters.get('task_urls', {})
        mode_urls = task_urls.get(mode, {})
        return mode_urls.get(task)
    
    def get_time_periods(self) -> List[str]:
        """Get list of valid time periods"""
        return self.parameters.get('time_periods', []).copy()
    
    def get_period_mappings(self) -> Dict[str, str]:
        """Get period normalization mappings"""
        return self.parameters.get('period_mappings', {}).copy()
    
    def normalize_periodo(self, periodo: str) -> Optional[str]:
        """
        Normalize period parameter using configuration mappings
        
        Args:
            periodo: Period string to normalize
            
        Returns:
            Normalized period string or None if invalid
        """
        if not periodo:
            return None
            
        period_mappings = self.get_period_mappings()
        
        # Direct mapping
        if periodo in period_mappings:
            return period_mappings[periodo]
        
        # Case-insensitive mapping
        for key, value in period_mappings.items():
            if periodo.lower() == key.lower():
                return value
        
        # If no mapping found, check if it's already a valid standard format
        valid_periods = self.get_time_periods()
        if periodo in valid_periods:
            return periodo
            
        return None
    
    # Convenience methods for backward compatibility
    def get_valid_sensor_types(self) -> List[str]:
        """Get list of valid sensor types"""
        return self.parameters['sensor_types'].copy()
    
    def get_valid_provinces(self) -> Dict[str, str]:
        """Get mapping of province names to codes"""
        return self.parameters['provinces']['name_to_code_mapping'].copy()
    
    def get_alert_zones(self) -> List[str]:
        """Get list of valid alert zones from global geography configuration"""
        return self.parameters.get('alert_zones', [])


# Global validator instance (lazy loaded)
_validator_instance = None


def get_validator() -> OMIRLValidator:
    """Get the global validator instance"""
    global _validator_instance
    if _validator_instance is None:
        _validator_instance = OMIRLValidator()
    return _validator_instance


# Convenience functions for backward compatibility
def validate_sensor_type(sensor_type: str) -> bool:
    """Validate sensor type against configured options"""
    is_valid, _, _ = get_validator().validate_sensor_type(sensor_type)
    return is_valid


def validate_provincia(provincia: str) -> Tuple[bool, Optional[str]]:
    """Validate and normalize province parameter"""
    is_valid, normalized, _ = get_validator().validate_provincia(provincia)
    return is_valid, normalized


def validate_zona(zona: str) -> bool:
    """Validate alert zone parameter"""
    is_valid, _, _ = get_validator().validate_zona(zona)
    return is_valid


def validate_periodo(periodo: str) -> bool:
    """Validate time period parameter"""
    is_valid, _, _ = get_validator().validate_periodo(periodo)
    return is_valid


# DEPRECATED: validate_mode_task_combination standalone function - mode parameter removed
# def validate_mode_task_combination(mode: str, task: str) -> bool:
#     """Validate that mode and task combination is supported"""
#     is_valid, _ = get_validator().validate_mode_task_combination(mode, task)
#     return is_valid


def get_valid_sensor_types() -> List[str]:
    """Get list of valid sensor types"""
    return get_validator().get_valid_sensor_types()


def get_valid_provinces() -> Dict[str, str]:
    """Get mapping of province names to codes"""
    return get_validator().get_valid_provinces()


def get_validation_errors(filters: Dict[str, Any]) -> List[str]:
    """
    Validate a complete filter set and return any errors
    
    Args:
        filters: Dictionary of filters to validate
        
    Returns:
        List of validation error messages (empty if all valid)
    """
    validator = get_validator()
    errors = []
    
    validation_methods = {
        'tipo_sensore': validator.validate_sensor_type,
        'provincia': validator.validate_provincia,
        'zona': validator.validate_zona,
        'periodo': validator.validate_periodo,
        'variabile_climatica': validator.validate_variabile_climatica
    }
    
    for filter_name, filter_value in filters.items():
        if filter_name in validation_methods and filter_value:
            is_valid, _, suggestions = validation_methods[filter_name](filter_value)
            if not is_valid:
                error_msg = f"Invalid {filter_name}: '{filter_value}'"
                if suggestions:
                    error_msg += f". Suggestions: {', '.join(suggestions[:3])}"
                errors.append(error_msg)
    
    return errors