rhaj/rhai_engine/src/terra_integration/terra_renderer.rs

use crate::terra_integration::script_manager::ScriptManager;
use std::collections::HashMap;
use std::path::Path;
use std::fs;
use std::sync::{Arc, RwLock};

/// A mock Terra Value type for demonstration purposes
/// In a real implementation, this would be the actual Terra Value type
#[derive(Debug, Clone)]
pub enum Value {
    String(String),
    Number(f64),
    Boolean(bool),
    Array(Vec<Value>),
    Object(HashMap<String, Value>),
    Null,
}

impl Value {
    pub fn from_string(s: impl Into<String>) -> Self {
        Value::String(s.into())
    }
    
    pub fn from_number(n: f64) -> Self {
        Value::Number(n)
    }
    
    pub fn from_bool(b: bool) -> Self {
        Value::Boolean(b)
    }
    
    pub fn as_string(&self) -> Option<&String> {
        if let Value::String(s) = self {
            Some(s)
        } else {
            None
        }
    }
    
    pub fn as_number(&self) -> Option<f64> {
        if let Value::Number(n) = self {
            Some(*n)
        } else {
            None
        }
    }
}

/// A mock Terra Context type for demonstration purposes
pub type Context = HashMap<String, Value>;

/// A mock Terra Template type for demonstration purposes
#[derive(Debug, Clone)]
pub struct Template {
    content: String,
}

/// A mock Terra TemplateEngine type for demonstration purposes 
pub struct TemplateEngine {
    // Using a simple closure that doesn't need Send + Sync
    filters: HashMap<String, Box<dyn Fn(Vec<Value>) -> Value>>,
}

impl TemplateEngine { 
    pub fn new() -> Self {
        Self {
            filters: HashMap::new(),
        }
    }
    
    pub fn register_filter<F>(&mut self, name: &str, filter: F)
    where
        F: Fn(Vec<Value>) -> Value + 'static, // No Send + Sync
    {
        self.filters.insert(name.to_string(), Box::new(filter));
    }
    
    pub fn compile(&self, template_content: &str) -> Result<Template, String> {
        // In a real implementation, this would compile the template
        // For this example, we just store the content
        Ok(Template {
            content: template_content.to_string(),
        })
    }

    pub fn render(&self, _template: &Template, context: &Context) -> Result<String, String> {
        // In a real implementation, this would render the template with the context
        // For this example, we just return a placeholder
        Ok(format!("Rendered template with {} filters and {} context variables",
                  self.filters.len(),
                  context.len()))
    }
}

/// TerraRenderer integrates Rhai scripts with Terra templates
pub struct TerraRenderer {
    script_manager: Arc<RwLock<ScriptManager>>,
    template_engine: TemplateEngine,
    templates: HashMap<String, Template>,
}

impl TerraRenderer {
    pub fn new(script_manager: Arc<RwLock<ScriptManager>>) -> Self {
        let mut template_engine = TemplateEngine::new();
        
        // Register all Rhai filters with Terra
        // Create a new local scope to limit the lifetime of the lock
        let filters = {
            // Get a read lock on the script manager
            let manager = script_manager.read().unwrap();
            // Get all the filters (returns a reference)
            let filters_ref = manager.get_all_filters();
            // Create a copy of the filter names for use outside the lock
            filters_ref.keys().cloned().collect::<Vec<String>>()
        };
                
        // Register each filter
        for name in filters {
            let script_manager_clone = script_manager.clone();
            let name_clone = name.clone();
            
            template_engine.register_filter(&name, move |args: Vec<Value>| {
                // Convert Terra Values to Rhai Dynamic values
                let rhai_args = args.into_iter()
                    .map(|v| Self::terra_value_to_rhai_dynamic(v))
                    .collect::<Vec<_>>();
                
                // Call the filter by name from the script manager
                match script_manager_clone.read().unwrap().call_filter(&name_clone, rhai_args) {
                    Ok(result) => Self::rhai_dynamic_to_terra_value(result),
                    Err(e) => Value::String(format!("Error: {}", e)),
                }
            });
        }
        
        Self {
            script_manager,
            template_engine,
            templates: HashMap::new(),
        }
    }
    
    /// Load a template from a file
    pub fn load_template(&mut self, name: &str, path: impl AsRef<Path>) -> Result<(), String> {
        let path = path.as_ref();
        
        // Read the template file
        let template_content = fs::read_to_string(path)
            .map_err(|e| format!("Failed to read template file {}: {}", path.display(), e))?;
        
        // Compile the template
        let template = self.template_engine.compile(&template_content)?;
        
        // Store the compiled template
        self.templates.insert(name.to_string(), template);
        
        Ok(())
    }
    
    /// Render a template with the given context
    pub fn render(&self, template_name: &str, context: Context) -> Result<String, String> {
        let template = self.templates.get(template_name)
            .ok_or_else(|| format!("Template not found: {}", template_name))?;
        
        // Render the template
        self.template_engine.render(template, &context)
    }
    
    /// Convert a Terra Value to a Rhai Dynamic
    fn terra_value_to_rhai_dynamic(value: Value) -> rhai::Dynamic {
        use rhai::Dynamic;
        
        match value {
            Value::String(s) => Dynamic::from(s),
            Value::Number(n) => Dynamic::from(n),
            Value::Boolean(b) => Dynamic::from(b),
            Value::Array(arr) => {
                let rhai_arr = arr.into_iter()
                    .map(Self::terra_value_to_rhai_dynamic)
                    .collect::<Vec<_>>();
                Dynamic::from(rhai_arr)
            },
            Value::Object(obj) => {
                let mut rhai_map = rhai::Map::new();
                for (k, v) in obj {
                    rhai_map.insert(k.into(), Self::terra_value_to_rhai_dynamic(v));
                }
                Dynamic::from(rhai_map)
            },
            Value::Null => Dynamic::UNIT,
        }
    }
    
    /// Convert a Rhai Dynamic to a Terra Value
    fn rhai_dynamic_to_terra_value(value: rhai::Dynamic) -> Value {
        if value.is::<String>() {
            Value::String(value.into_string().unwrap())
        } else if value.is::<i64>() {
            Value::Number(value.as_int().unwrap() as f64)
        } else if value.is::<f64>() {
            Value::Number(value.as_float().unwrap())
        } else if value.is::<bool>() {
            Value::Boolean(value.as_bool().unwrap())
        } else if value.is_array() {
            let arr = value.into_array().unwrap();
            let terra_arr = arr.into_iter()
                .map(Self::rhai_dynamic_to_terra_value)
                .collect();
            Value::Array(terra_arr)
        } else if value.is::<rhai::Map>() {
            // Use a different approach to handle maps
            // Create a new HashMap for Terra
            let mut terra_map = HashMap::new();
            
            // Get the Map as a reference and convert each key-value pair
            if let Some(map) = value.try_cast::<rhai::Map>() {
                for (k, v) in map.iter() {
                    terra_map.insert(k.to_string(), Self::rhai_dynamic_to_terra_value(v.clone()));
                }
            }
            Value::Object(terra_map)
        } else {
            Value::Null
        }
    }
}