zen-engine 2.0.1

use crate::support::{create_fs_loader, load_raw_test_data, load_test_data, test_data_root};
use serde::Deserialize;
use serde_json::json;
use std::fs;
use std::io::Read;
use std::ops::Deref;
use std::path::Path;
use std::sync::Arc;
use tokio::runtime::Builder;
use zen_engine::loader::{LoaderError, MemoryLoader};
use zen_engine::model::{DecisionNode, DecisionNodeKind, FunctionNodeContent, GraphContent};
use zen_engine::Variable;
use zen_engine::{DecisionEngine, EvaluationError, EvaluationOptions};

mod support;

#[tokio::test]
#[cfg_attr(miri, ignore)]
async fn engine_memory_loader() {
    let memory_loader = Arc::new(MemoryLoader::default());
    memory_loader.add("table", load_test_data("table.json"));
    memory_loader.add("function", load_test_data("function.json"));

    let engine = DecisionEngine::default().with_loader(memory_loader.clone());
    let table = engine
        .evaluate("table", json!({ "input": 12 }).into())
        .await;
    let function = engine
        .evaluate("function", json!({ "input": 12 }).into())
        .await;

    memory_loader.remove("function");
    let not_found = engine.evaluate("function", json!({}).into()).await;

    assert_eq!(table.unwrap().result, json!({"output": 10}).into());
    assert_eq!(function.unwrap().result, json!({"output": 24}).into());
    assert_eq!(not_found.unwrap_err().to_string(), "Loader error");
}

#[tokio::test]
#[cfg_attr(miri, ignore)]
async fn engine_precompiles_graphs() {
    let memory_loader = Arc::new(MemoryLoader::default());
    memory_loader.add("table", load_test_data("table.json"));

    let engine = DecisionEngine::default().with_loader(memory_loader.clone());
    let failures = engine.compile();
    assert!(failures.is_empty());

    memory_loader.remove("table");
    let table = engine
        .evaluate("table", json!({ "input": 12 }).into())
        .await;

    assert_eq!(table.unwrap().result, json!({"output": 10}).into());
}

#[tokio::test]
#[cfg_attr(miri, ignore)]
async fn engine_filesystem_loader() {
    let engine = DecisionEngine::default().with_loader(Arc::new(create_fs_loader()));
    let table = engine
        .evaluate("table.json", json!({ "input": 12 }).into())
        .await;
    let function = engine
        .evaluate("function.json", json!({ "input": 12 }).into())
        .await;
    let not_found = engine.evaluate("invalid_file", json!({}).into()).await;

    assert_eq!(table.unwrap().result, json!({"output": 10}).into());
    assert_eq!(function.unwrap().result, json!({"output": 24}).into());
    assert_eq!(not_found.unwrap_err().to_string(), "Loader error");
}

#[tokio::test]
#[cfg_attr(miri, ignore)]
async fn engine_closure_loader() {
    let engine = DecisionEngine::default().with_closure_loader(|key| async {
        match key.as_str() {
            "function" => Ok(Arc::new(load_test_data("function.json").into())),
            "table" => Ok(Arc::new(load_test_data("table.json").into())),
            _ => Err(LoaderError::NotFound(key).into()),
        }
    });

    let table = engine
        .evaluate("table", json!({ "input": 12 }).into())
        .await;
    let function = engine
        .evaluate("function", json!({ "input": 12 }).into())
        .await;
    let not_found = engine.evaluate("invalid_file", json!({}).into()).await;

    assert_eq!(table.unwrap().result, json!({"output": 10}).into());
    assert_eq!(function.unwrap().result, json!({"output": 24}).into());
    assert_eq!(not_found.unwrap_err().to_string(), "Loader error");
}

#[test]
fn engine_noop_loader() {
    let rt = Builder::new_current_thread().build().unwrap();
    // Default engine is noop
    let engine = DecisionEngine::default();
    let result = rt.block_on(engine.evaluate("any.json", json!({}).into()));

    assert_eq!(result.unwrap_err().to_string(), "Loader error");
}

#[test]
fn engine_get_decision() {
    let rt = Builder::new_current_thread().build().unwrap();
    let engine = DecisionEngine::default().with_loader(Arc::new(create_fs_loader()));

    assert!(rt
        .block_on(engine.get_decision("table.json"))
        .is_ok_and(|inner| inner.is_ok()));
    assert!(rt.block_on(engine.get_decision("any.json")).is_err());
}

#[test]
fn engine_create_decision() {
    let engine = DecisionEngine::default();
    let _ = engine
        .create_decision(Arc::new(load_test_data("table.json").into()))
        .unwrap();
}

#[tokio::test]
#[cfg_attr(miri, ignore)]
async fn engine_errors() {
    let engine = DecisionEngine::default().with_loader(Arc::new(create_fs_loader()));

    let infinite_fn = engine
        .evaluate("infinite-function.json", json!({}).into())
        .await;
    match infinite_fn.unwrap_err().deref() {
        EvaluationError::NodeError {
            node_id, source, ..
        } => {
            assert_eq!(node_id.deref(), "e0fd96d0-44dc-4f0e-b825-06e56b442d78");
            assert!(source.to_string().contains("interrupted"));
        }
        _ => assert!(false, "Wrong error type"),
    }

    let recursive = engine
        .evaluate("recursive-table1.json", json!({}).into())
        .await;
    match recursive.unwrap_err().deref() {
        EvaluationError::NodeError { source, .. } => {
            println!("{:?}", source);
            assert_eq!(source.to_string(), "Depth limit exceeded")
        }
        _ => assert!(false, "Depth limit not exceeded"),
    }
}

#[test]
fn engine_with_trace() {
    let rt = Builder::new_current_thread().build().unwrap();
    let engine = DecisionEngine::default().with_loader(Arc::new(create_fs_loader()));

    let table_r = rt.block_on(engine.evaluate("table.json", json!({ "input": 12 }).into()));
    let table_opt_r = rt.block_on(engine.evaluate_with_opts(
        "table.json",
        json!({ "input": 12 }).into(),
        EvaluationOptions {
            trace: true,
            ..Default::default()
        },
    ));

    let table = table_r.unwrap();
    let table_opt = table_opt_r.unwrap();

    assert!(table.trace.is_none());
    assert!(table_opt.trace.is_some());

    let trace = table_opt.trace.unwrap().into_graph().unwrap();
    assert_eq!(trace.len(), 3); // trace for each node
}

#[tokio::test]
#[cfg_attr(miri, ignore)]
async fn engine_function_imports() {
    let function_content = load_test_data("function.json");

    let imports_js_path = Path::new("js").join("imports.js");
    let mut replace_buffer = load_raw_test_data(imports_js_path.to_str().unwrap());
    let mut replace_data = String::new();
    replace_buffer.read_to_string(&mut replace_data).unwrap();

    let new_nodes = function_content
        .nodes
        .into_iter()
        .map(|node| match &node.kind {
            DecisionNodeKind::FunctionNode { .. } => {
                let new_kind = DecisionNodeKind::FunctionNode {
                    content: FunctionNodeContent::Version1(Arc::from(replace_data.as_str())),
                };

                Arc::new(DecisionNode {
                    id: node.id.clone(),
                    name: node.name.clone(),
                    kind: new_kind,
                })
            }
            _ => node,
        })
        .collect::<Vec<_>>();

    let function_content = {
        let mut content = GraphContent::default();
        content.edges = function_content.edges;
        content.nodes = new_nodes;
        content
    };
    let decision = DecisionEngine::default()
        .create_decision(Arc::new(function_content.into()))
        .unwrap();
    let response = decision.evaluate(json!({}).into()).await.unwrap();

    #[derive(Deserialize, Debug)]
    #[serde(rename_all = "camelCase")]
    struct GraphResult {
        bigjs_tests: Vec<bool>,
        bigjs_valid: bool,
        dayjs_valid: bool,
        moment_valid: bool,
    }

    let result = serde_json::from_value::<GraphResult>(response.result.to_value()).unwrap();

    assert!(result.bigjs_tests.iter().all(|v| *v));
    assert!(result.bigjs_valid);
    assert!(result.dayjs_valid);
    assert!(result.moment_valid);
}

#[tokio::test]
async fn engine_switch_node() {
    let engine = DecisionEngine::default().with_loader(Arc::new(create_fs_loader()));

    let switch_node_r = engine
        .evaluate("switch-node.json", json!({ "color": "yellow" }).into())
        .await;

    let table = switch_node_r.unwrap();
    println!("{table:?}");
}

#[tokio::test]
#[cfg_attr(miri, ignore)]
async fn engine_graph_tests() {
    mock_datetime();

    #[derive(Deserialize)]
    #[serde(rename_all = "camelCase")]
    struct TestCase {
        input: Variable,
        output: Variable,
    }

    #[derive(Deserialize)]
    #[serde(rename_all = "camelCase")]
    struct TestData {
        tests: Vec<TestCase>,
        #[serde(flatten)]
        decision_content: GraphContent,
    }

    let engine = DecisionEngine::default();

    let graphs_path = Path::new(test_data_root().as_str()).join("graphs");
    let file_list = fs::read_dir(graphs_path).unwrap();
    for maybe_file in file_list {
        let Ok(file) = maybe_file else {
            panic!("Failed to read DirEntry {maybe_file:?}");
        };

        let file_name = file.file_name().to_str().map(|s| s.to_string()).unwrap();
        let file_contents = fs::read_to_string(file.path()).expect("valid file data");
        let test_data: TestData = serde_json::from_str(&file_contents).expect("Valid JSON");

        let decision = engine
            .create_decision(Arc::new(test_data.decision_content.clone().into()))
            .unwrap();

        let mut decision_compiled = engine
            .create_decision(Arc::new(test_data.decision_content.into()))
            .unwrap();
        decision_compiled.compile();

        for test_case in test_data.tests {
            let input = test_case.input.clone();
            let result = decision.evaluate(input.clone()).await.unwrap().result;
            let result_compiled = decision_compiled
                .evaluate(input.clone())
                .await
                .unwrap()
                .result;

            assert_eq!(
                test_case.output, result,
                "Decision file: {file_name}.\nInput:\n {input:#?}"
            );

            assert_eq!(
                test_case.output, result_compiled,
                "Compiled decision file: {file_name}.\nInput:\n {input:#?}"
            );
        }
    }
}

fn mock_datetime() {
    std::env::set_var("__ZEN_MOCK_UTC_TIME", "2025-08-19T16:55:02.078Z");
}

#[tokio::test]
#[cfg_attr(miri, ignore)]
async fn engine_snapshot_tests() {
    mock_datetime();

    #[derive(Deserialize)]
    #[serde(rename_all = "camelCase")]
    struct TestCase {
        input: Variable,
        _output: Variable,
    }

    #[derive(Deserialize)]
    #[serde(rename_all = "camelCase")]
    struct TestData {
        tests: Vec<TestCase>,
        #[serde(flatten)]
        decision_content: GraphContent,
    }

    let engine = DecisionEngine::default();

    let graphs_path = Path::new(test_data_root().as_str()).join("graphs");
    let file_list = fs::read_dir(graphs_path).unwrap();
    for maybe_file in file_list {
        let Ok(file) = maybe_file else {
            panic!("Failed to read DirEntry {maybe_file:?}");
        };

        let file_name = file.file_name().to_str().map(|s| s.to_string()).unwrap();
        let file_name = if let Some(pos) = file_name.rfind('.') {
            file_name[..pos].to_string()
        } else {
            file_name
        };
        let file_contents = fs::read_to_string(file.path()).expect("valid file data");
        let test_data: TestData = serde_json::from_str(&file_contents).expect("Valid JSON");

        let decision = engine
            .create_decision(Arc::new(test_data.decision_content.clone().into()))
            .unwrap();

        let mut decision_compiled = engine
            .create_decision(Arc::new(test_data.decision_content.into()))
            .unwrap();
        decision_compiled.compile();

        for (index, test_case) in test_data.tests.iter().enumerate() {
            let input = test_case.input.clone();
            let result = decision
                .evaluate_with_opts(
                    input.clone(),
                    EvaluationOptions {
                        trace: true,
                        ..Default::default()
                    },
                )
                .await
                .unwrap();
            let result_compiled = decision_compiled
                .evaluate_with_opts(
                    input.clone(),
                    EvaluationOptions {
                        trace: true,
                        ..Default::default()
                    },
                )
                .await
                .unwrap();
            let serialized_result = serde_json::to_value(&result_compiled).unwrap();
            let serialized_result_compiled = serde_json::to_value(&result).unwrap();
            insta::assert_yaml_snapshot!(format!("{}_{}", file_name, index), serialized_result, {
                ".performance" => "[perf]",
                ".trace.*.performance" => "[perf]"
            });
            insta::assert_yaml_snapshot!(format!("{}_{}", file_name, index), serialized_result_compiled, {
                ".performance" => "[perf]",
                ".trace.*.performance" => "[perf]"
            });
        }
    }
}

#[tokio::test]
#[cfg_attr(miri, ignore)]
async fn engine_function_v2() {
    let engine = DecisionEngine::default().with_loader(Arc::new(create_fs_loader()));

    for _ in 0..1_000 {
        let function_opt_r = engine
            .evaluate_with_opts(
                "function-v2.json",
                json!({ "input": 12 }).into(),
                EvaluationOptions {
                    trace: true,
                    ..Default::default()
                },
            )
            .await;

        assert!(function_opt_r.is_ok(), "function v2 has errored");

        let function_opt = function_opt_r.unwrap();
        let trace = function_opt.trace.unwrap().into_graph().unwrap();
        assert_eq!(trace.len(), 3); // trace for each node

        assert_eq!(
            function_opt.result,
            json!({ "hello": "world", "multiplied": 24 }).into()
        )
    }
}

#[tokio::test]
async fn test_validation() {
    let engine = DecisionEngine::default().with_loader(Arc::new(create_fs_loader()));

    let context_valid = json!({
        "color": "red",
        "customer": {
            "firstName": "John",
            "lastName": "Doe",
            "email": "john@doe.com",
            "age": 20
        }
    });

    let context_invalid = json!({
         "color": "redd",
        "customer": {
            "firstName": "John",
            "lastName": "Doe",
            "email": "john@doe.com",
            "age": 20
        }
    });

    assert!(engine
        .evaluate("customer-input-schema.json", context_valid.clone().into())
        .await
        .is_ok());
    assert!(engine
        .evaluate("customer-input-schema.json", context_invalid.clone().into())
        .await
        .is_err());

    assert!(engine
        .evaluate("customer-output-schema.json", context_valid.clone().into())
        .await
        .is_ok());
    assert!(engine
        .evaluate(
            "customer-output-schema.json",
            context_invalid.clone().into()
        )
        .await
        .is_err());
}

#[tokio::test]
#[cfg_attr(miri, ignore)]
async fn test_nodes_reference() {
    let engine = DecisionEngine::default().with_loader(Arc::new(create_fs_loader()));

    let evaluation = engine
        .evaluate("$nodes-parent.json", json!({ "hello": "world" }).into())
        .await;

    assert!(evaluation.is_ok());
    assert_eq!(
        evaluation.unwrap().result.to_value(),
        json!({
            "expressionParentNodes": { "request": { "hello": "world" } },
            "expressionRequest": { "hello": "world" },
            "functionParentNodes": { "request": { "hello": "world" } },
            "functionRequest": { "hello": "world" },
        })
    );
}

#[tokio::test]
async fn decision_table_index_matches_linear_semantics() {
    let table_node = json!({
        "id": "dt-node",
        "type": "decisionTableNode",
        "name": "dt",
        "content": {
            "hitPolicy": "first",
            "inputs": [
                {"id": "c1", "name": "Tier", "field": "tier"},
                {"id": "c2", "name": "Amount", "field": "amount"},
                {"id": "c3", "name": "Active", "field": "active"}
            ],
            "outputs": [{"id": "o1", "name": "Rate", "field": "rate"}],
            "rules": [
                {"_id": "r1", "c1": "'gold'", "c2": "100", "c3": "true", "o1": "1"},
                {"_id": "r2", "c1": "'gold'", "c2": "> 500", "c3": "", "o1": "2"},
                {"_id": "r3", "c1": "'silver'", "c2": "[100..200]", "c3": "", "o1": "3"},
                {"_id": "r4", "c1": "'silver', 'bronze'", "c2": "", "c3": "false", "o1": "4"},
                {"_id": "r5", "c1": "", "c2": "42", "c3": "", "o1": "5"},
                {"_id": "r6", "c1": "'gold'", "c2": "", "c3": "", "o1": "6"},
                {"_id": "r7", "c1": "'bronze'", "c2": "7, 8, 9", "c3": "true", "o1": "7"},
                {"_id": "r8", "c1": "", "c2": "", "c3": "", "o1": "8"},
                {"_id": "r9", "c1": "'platinum'", "c2": "1000", "c3": "true", "o1": "9"}
            ]
        }
    });
    let graph = json!({
        "nodes": [
            {"id": "in", "type": "inputNode", "name": "request"},
            table_node,
            {"id": "out", "type": "outputNode", "name": "response"}
        ],
        "edges": [
            {"id": "e1", "sourceId": "in", "targetId": "dt-node"},
            {"id": "e2", "sourceId": "dt-node", "targetId": "out"}
        ]
    });

    let probes = [
        json!({"tier": "gold", "amount": 100, "active": true}),
        json!({"tier": "gold", "amount": 600, "active": false}),
        json!({"tier": "silver", "amount": 150, "active": true}),
        json!({"tier": "silver", "amount": 50, "active": false}),
        json!({"tier": "bronze", "amount": 8, "active": true}),
        json!({"tier": "unknown", "amount": 42, "active": false}),
        json!({"tier": "unknown", "amount": 0, "active": false}),
        json!({"tier": "platinum", "amount": 1000, "active": true}),
        json!({"tier": 5, "amount": "x", "active": null}),
    ];

    for hit_policy in ["first", "collect"] {
        let mut graph = graph.clone();
        graph["nodes"][1]["content"]["hitPolicy"] = json!(hit_policy);
        let mut content: GraphContent = serde_json::from_value(graph).unwrap();
        content.compile();
        let decision = DecisionEngine::default()
            .create_decision(Arc::new(content.into()))
            .unwrap();

        for probe in &probes {
            let indexed = decision
                .evaluate(Variable::from(probe))
                .await
                .unwrap()
                .result;
            let linear = decision
                .evaluate_with_opts(
                    Variable::from(probe),
                    EvaluationOptions {
                        trace: true,
                        max_depth: 5,
                    },
                )
                .await
                .unwrap()
                .result;
            assert_eq!(
                serde_json::to_value(&indexed).unwrap(),
                serde_json::to_value(&linear).unwrap(),
                "hit_policy={hit_policy} probe={probe}"
            );
        }
    }
}