torsh-fx 0.1.2

//! Module tracing

use crate::{Edge, FxGraph, Node, TorshResult};
use petgraph::graph::NodeIndex;
use std::collections::HashMap;

/// Tracer for recording module operations
pub struct ModuleTracer {
    graph: FxGraph,
    node_map: HashMap<String, NodeIndex>,
    next_node_id: usize,
}

impl ModuleTracer {
    /// Create a new tracer
    pub fn new() -> Self {
        Self {
            graph: FxGraph::new(),
            node_map: HashMap::new(),
            next_node_id: 0,
        }
    }

    /// Generate a unique node name
    fn next_node_name(&mut self) -> String {
        let node_id = self.next_node_id;
        let name = format!("node_{node_id}");
        self.next_node_id += 1;
        name
    }

    /// Add an input node
    pub fn add_input(&mut self, name: &str) -> NodeIndex {
        let node_idx = self.graph.graph.add_node(Node::Input(name.to_string()));
        self.graph.inputs.push(node_idx);
        self.node_map.insert(name.to_string(), node_idx);
        node_idx
    }

    /// Add a call node
    pub fn add_call(&mut self, op_name: &str, args: Vec<String>) -> NodeIndex {
        let node_name = self.next_node_name();
        let node_idx = self
            .graph
            .graph
            .add_node(Node::Call(op_name.to_string(), args.clone()));

        // Add edges from argument nodes
        for arg in &args {
            if let Some(&arg_idx) = self.node_map.get(arg) {
                self.graph
                    .graph
                    .add_edge(arg_idx, node_idx, Edge { name: arg.clone() });
            }
        }

        self.node_map.insert(node_name.clone(), node_idx);
        node_idx
    }

    /// Add an output node
    pub fn add_output(&mut self, input_name: &str) -> NodeIndex {
        let node_idx = self.graph.graph.add_node(Node::Output);

        if let Some(&input_idx) = self.node_map.get(input_name) {
            self.graph.graph.add_edge(
                input_idx,
                node_idx,
                Edge {
                    name: input_name.to_string(),
                },
            );
        }

        self.graph.outputs.push(node_idx);
        node_idx
    }

    /// Add a conditional node (if/else)
    pub fn add_conditional(
        &mut self,
        condition: &str,
        then_branch: Vec<String>,
        else_branch: Vec<String>,
    ) -> NodeIndex {
        let node_name = self.next_node_name();
        let node_idx = self.graph.graph.add_node(Node::Conditional {
            condition: condition.to_string(),
            then_branch: then_branch.clone(),
            else_branch: else_branch.clone(),
        });

        // Add edge from condition node
        if let Some(&cond_idx) = self.node_map.get(condition) {
            self.graph.graph.add_edge(
                cond_idx,
                node_idx,
                Edge {
                    name: condition.to_string(),
                },
            );
        }

        // Add edges from branch inputs
        for input in then_branch.iter().chain(else_branch.iter()) {
            if let Some(&input_idx) = self.node_map.get(input) {
                self.graph.graph.add_edge(
                    input_idx,
                    node_idx,
                    Edge {
                        name: input.clone(),
                    },
                );
            }
        }

        self.node_map.insert(node_name, node_idx);
        node_idx
    }

    /// Add a loop node
    pub fn add_loop(
        &mut self,
        condition: &str,
        body: Vec<String>,
        loop_vars: Vec<String>,
    ) -> NodeIndex {
        let node_name = self.next_node_name();
        let node_idx = self.graph.graph.add_node(Node::Loop {
            condition: condition.to_string(),
            body: body.clone(),
            loop_vars: loop_vars.clone(),
        });

        // Add edge from condition node
        if let Some(&cond_idx) = self.node_map.get(condition) {
            self.graph.graph.add_edge(
                cond_idx,
                node_idx,
                Edge {
                    name: condition.to_string(),
                },
            );
        }

        // Add edges from loop variables and body inputs
        for input in body.iter().chain(loop_vars.iter()) {
            if let Some(&input_idx) = self.node_map.get(input) {
                self.graph.graph.add_edge(
                    input_idx,
                    node_idx,
                    Edge {
                        name: input.clone(),
                    },
                );
            }
        }

        self.node_map.insert(node_name, node_idx);
        node_idx
    }

    /// Add a merge node for control flow convergence
    pub fn add_merge(&mut self, inputs: Vec<String>) -> NodeIndex {
        let node_name = self.next_node_name();
        let node_idx = self.graph.graph.add_node(Node::Merge {
            inputs: inputs.clone(),
        });

        // Add edges from all inputs
        for input in &inputs {
            if let Some(&input_idx) = self.node_map.get(input) {
                self.graph.graph.add_edge(
                    input_idx,
                    node_idx,
                    Edge {
                        name: input.clone(),
                    },
                );
            }
        }

        self.node_map.insert(node_name, node_idx);
        node_idx
    }

    /// Add a GetAttr node for attribute access
    pub fn add_get_attr(&mut self, target: &str, attr: &str) -> NodeIndex {
        let node_name = self.next_node_name();
        let node_idx = self.graph.graph.add_node(Node::GetAttr {
            target: target.to_string(),
            attr: attr.to_string(),
        });

        // Add edge from target node
        if let Some(&target_idx) = self.node_map.get(target) {
            self.graph.graph.add_edge(
                target_idx,
                node_idx,
                Edge {
                    name: target.to_string(),
                },
            );
        }

        self.node_map.insert(node_name, node_idx);
        node_idx
    }

    /// Get the final graph
    pub fn finalize(self) -> FxGraph {
        self.graph
    }
}

/// Module trait placeholder for tracing
pub trait Module {
    /// Forward pass method (placeholder)
    fn forward(&self, inputs: &[String]) -> TorshResult<Vec<String>>;
}

/// Basic module tracing implementation
pub fn trace(_module: &dyn Module) -> TorshResult<FxGraph> {
    let mut tracer = ModuleTracer::new();

    // Add a placeholder input
    let _input_node = tracer.add_input("input");

    // For now, create a simple linear graph representing a basic forward pass
    // In a full implementation, this would actually trace through the module's forward method
    let _linear_node = tracer.add_call("linear", vec!["input".to_string()]);
    let _output_node = tracer.add_output("node_0");

    Ok(tracer.finalize())
}

/// Symbolic execution context for tracing
pub struct SymbolicTensor {
    pub name: String,
    pub shape: Vec<usize>,
    pub node: NodeIndex,
}

impl SymbolicTensor {
    pub fn new(name: String, shape: Vec<usize>, node: NodeIndex) -> Self {
        Self { name, shape, node }
    }
}

/// Proxy for modules during tracing
pub trait TracingProxy {
    /// Execute the module in tracing mode
    fn trace_forward(
        &self,
        tracer: &mut ModuleTracer,
        inputs: &[SymbolicTensor],
    ) -> TorshResult<Vec<SymbolicTensor>>;
}

/// Default implementation for basic modules
impl<T: Module> TracingProxy for T {
    fn trace_forward(
        &self,
        tracer: &mut ModuleTracer,
        inputs: &[SymbolicTensor],
    ) -> TorshResult<Vec<SymbolicTensor>> {
        // Default implementation: create a generic call node
        let input_names: Vec<String> = inputs.iter().map(|t| t.name.clone()).collect();
        let output_node = tracer.add_call("module_call", input_names);
        let node_index = output_node.index();
        let output_name = format!("node_{node_index}");

        // Assume output shape is same as first input for simplicity
        let output_shape = inputs.first().map(|t| t.shape.clone()).unwrap_or_default();

        Ok(vec![SymbolicTensor::new(
            output_name,
            output_shape,
            output_node,
        )])
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_tracer_basic() {
        let mut tracer = ModuleTracer::new();

        let _input = tracer.add_input("x");
        let _relu = tracer.add_call("relu", vec!["x".to_string()]);
        let _output = tracer.add_output("node_0");

        let graph = tracer.finalize();
        assert_eq!(graph.inputs.len(), 1);
        assert_eq!(graph.outputs.len(), 1);
    }

    #[test]
    fn test_symbolic_tensor() {
        let tensor = SymbolicTensor::new("test".to_string(), vec![2, 3], NodeIndex::new(0));
        assert_eq!(tensor.name, "test");
        assert_eq!(tensor.shape, vec![2, 3]);
    }

    #[test]
    fn test_conditional_node() {
        let mut tracer = ModuleTracer::new();

        let _input = tracer.add_input("x");
        let _condition = tracer.add_call("gt", vec!["x".to_string()]);
        let _then_result = tracer.add_call("relu", vec!["x".to_string()]);
        let _else_result = tracer.add_call("sigmoid", vec!["x".to_string()]);

        let _conditional = tracer.add_conditional(
            "node_0",
            vec!["node_1".to_string()],
            vec!["node_2".to_string()],
        );

        let _output = tracer.add_output("node_3");

        let graph = tracer.finalize();
        assert_eq!(graph.inputs.len(), 1);
        assert_eq!(graph.outputs.len(), 1);
        assert!(graph.node_count() >= 5); // input, condition, then, else, conditional, output
    }

    #[test]
    fn test_loop_node() {
        let mut tracer = ModuleTracer::new();

        let _input = tracer.add_input("x");
        let _condition = tracer.add_call("lt", vec!["x".to_string()]);
        let _body_op = tracer.add_call("add", vec!["x".to_string()]);

        let _loop_node =
            tracer.add_loop("node_0", vec!["node_1".to_string()], vec!["x".to_string()]);

        let _output = tracer.add_output("node_2");

        let graph = tracer.finalize();
        assert_eq!(graph.inputs.len(), 1);
        assert_eq!(graph.outputs.len(), 1);
    }

    #[test]
    fn test_merge_node() {
        let mut tracer = ModuleTracer::new();

        let _input1 = tracer.add_input("x");
        let _input2 = tracer.add_input("y");
        let _op1 = tracer.add_call("relu", vec!["x".to_string()]);
        let _op2 = tracer.add_call("sigmoid", vec!["y".to_string()]);

        let _merge = tracer.add_merge(vec!["node_0".to_string(), "node_1".to_string()]);
        let _output = tracer.add_output("node_2");

        let graph = tracer.finalize();
        assert_eq!(graph.inputs.len(), 2);
        assert_eq!(graph.outputs.len(), 1);
    }

    #[test]
    fn test_get_attr_node() {
        let mut tracer = ModuleTracer::new();

        let _input = tracer.add_input("module");
        let _attr = tracer.add_get_attr("module", "weight");
        let _output = tracer.add_output("node_0");

        let graph = tracer.finalize();
        assert_eq!(graph.inputs.len(), 1);
        assert_eq!(graph.outputs.len(), 1);
    }
}