use brick::Building;
use brick::mcp::Catalog;
use brick::scan;
use serde_json::{Value, json};
use std::collections::BTreeMap;
use std::fs;

fn scan_files(files: &[(&str, &str)]) -> Building {
    let root = tempfile::tempdir().unwrap();
    for (path, content) in files {
        let file = root.path().join(path);
        fs::create_dir_all(file.parent().unwrap()).unwrap();
        fs::write(file, content).unwrap();
    }
    scan::scan(root.path()).unwrap()
}

/// function name -> (status, reason kinds) for every function in the model.
fn statuses(model: Building, closed_world: bool) -> BTreeMap<String, (String, Vec<String>)> {
    let catalog = Catalog::new(model).unwrap();
    let result = catalog
        .call(
            "brick_uncalled",
            json!({"assume_closed_world": closed_world, "include_unknown": true, "limit": 1000}),
        )
        .unwrap();
    let mut found = BTreeMap::new();
    for (status, list) in [("unreferenced", "unreferenced"), ("unknown", "unknown")] {
        for report in result[list].as_array().unwrap() {
            let reasons = report["reasons"]
                .as_array()
                .unwrap()
                .iter()
                .map(|r| r["kind"].as_str().unwrap().to_owned())
                .collect();
            found.insert(
                report["node"]["name"].as_str().unwrap().to_owned(),
                (status.to_owned(), reasons),
            );
        }
    }
    found
}

fn cpp_model() -> Building {
    scan_files(&[
        (
            "src/app.h",
            "#include <string>\nstruct Base { virtual void hook(); };\nstruct Widget : Base {\n  void hook() override;\n  int size() const;\n  Widget();\n};\nint shared();\n",
        ),
        (
            "src/app.cpp",
            "#include \"app.h\"\n#include <mutex>\nWidget::Widget() {}\nvoid Base::hook() {}\nvoid Widget::hook() {}\nint Widget::size() const { return 0; }\nstatic std::mutex& lockObject() { static std::mutex m; return m; }\nstatic int unusedHelper() { return 1; }\nstatic int callback(int x) { return x; }\nint shared() { return 2; }\nWidget make();\nint main() {\n  std::lock_guard<std::mutex> guard(lockObject());\n  std::string text;\n  text.size();\n  make().size();\n  int (*fp)(int) = callback;\n  return fp(1) + shared();\n}\n",
        ),
    ])
}

#[test]
fn cpp_statuses_separate_dead_code_from_unresolvable_uses() {
    let found = statuses(cpp_model(), false);
    // Only resolved callers are omitted: shared() and lockObject() (via the vexing parse).
    assert!(!found.contains_key("shared"));
    assert!(!found.contains_key("lockObject"));
    assert_eq!(found["unusedHelper"], ("unreferenced".into(), vec![]));
    let reasons = |name: &str| found[name].1.clone();
    assert_eq!(found["size"].0, "unknown");
    // make().size() may reach Widget::size; std::string::size cannot.
    assert!(reasons("size").contains(&"unresolved-call-sites".to_owned()));
    assert!(reasons("callback").contains(&"referenced-by-name".to_owned()));
    assert!(reasons("hook").contains(&"virtual".to_owned()));
    assert!(reasons("Widget").contains(&"implicit-invocation".to_owned()));
    assert!(reasons("main").contains(&"entry-point".to_owned()));
}

#[test]
fn closed_world_drops_linkage_but_keeps_evidence_of_indirect_use() {
    let open = statuses(cpp_model(), false);
    let closed = statuses(cpp_model(), true);
    assert!(open["size"].1.contains(&"external-linkage".to_owned()));
    assert!(!closed["size"].1.contains(&"external-linkage".to_owned()));
    assert_eq!(closed["size"].0, "unknown");
    assert_eq!(closed["unusedHelper"].0, "unreferenced");
}

#[test]
fn rust_attributes_attribute_strings_and_trait_impls_are_uses() {
    let model = scan_files(&[(
        "src/lib.rs",
        "use std::fmt;\nstruct Point;\nimpl fmt::Display for Point {\n    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { Ok(()) }\n}\n#[derive(serde::Deserialize)]\nstruct Config {\n    #[serde(deserialize_with = \"crate::parse_flag\")]\n    flag: bool,\n}\nfn parse_flag() {}\nfn orphan() {}\n#[test]\nfn checks() {}\n#[cfg(test)]\nmod tests {\n    fn helper() {}\n}\n",
    )]);
    let found = statuses(model, true);
    assert_eq!(found["orphan"], ("unreferenced".into(), vec![]));
    assert!(found["fmt"].1.contains(&"trait-impl".to_owned()));
    assert!(
        found["parse_flag"]
            .1
            .contains(&"referenced-by-name".to_owned())
    );
    assert!(
        found["checks"]
            .1
            .contains(&"framework-attribute".to_owned())
    );
    assert!(found["helper"].1.contains(&"test-code".to_owned()));
}

#[test]
fn callers_query_reports_resolved_callers_basis_and_rejects_non_functions() {
    let model = cpp_model();
    let shared = model
        .nodes
        .iter()
        .find(|n| n.name == "shared" && n.path.as_deref() == Some("src/app.cpp"))
        .unwrap()
        .id
        .clone();
    let file = model
        .nodes
        .iter()
        .find(|n| {
            n.path.as_deref() == Some("src/app.cpp") && n.kind == brick::model::NodeKind::File
        })
        .unwrap()
        .id
        .clone();
    let catalog = Catalog::new(model).unwrap();
    let result = catalog
        .call("brick_callers", json!({"node_id": shared}))
        .unwrap();
    let report = &result["report"];
    assert_eq!(report["status"], "resolved");
    assert_eq!(report["basis"], "heuristic");
    assert_eq!(report["callers"].as_array().unwrap().len(), 1);
    assert!(
        result["coverage"]["cpp"]["call_site_count"]
            .as_u64()
            .unwrap()
            > 0
    );
    assert!(result["caveat"].as_str().unwrap().contains("not proof"));
    assert!(
        catalog
            .call("brick_callers", json!({"node_id": file}))
            .is_err()
    );
    assert!(
        catalog
            .call(
                "brick_callers",
                json!({"node_id": shared, "extra": Value::Null})
            )
            .is_err()
    );
}

#[test]
fn macro_bodies_and_syntax_errors_make_functions_unknown_not_dead() {
    let model = scan_files(&[
        (
            "src/plugin.cpp",
            "static void* open_impl(const char* name) { return nullptr; }\n#define open_library open_impl\nstatic void* unused_impl() { return nullptr; }\nvoid* load() { return open_library(\"x\"); }\n",
        ),
        (
            "src/broken.cpp",
            "namespace {\n#if defined(A)\n}\n#endif\nstatic int lost() { return 1; }\n",
        ),
    ]);
    let found = statuses(model, true);
    assert!(
        found["open_impl"]
            .1
            .contains(&"referenced-by-name".to_owned())
    );
    assert_eq!(found["unused_impl"], ("unreferenced".into(), vec![]));
    assert!(
        found["lost"].1.contains(&"parse-incomplete".to_owned()),
        "{found:?}"
    );
}

#[test]
fn template_parameters_aliases_and_protocol_methods_are_not_dead() {
    let model = scan_files(&[
        (
            "src/repair.h",
            "#include <memory>\nnamespace app {\nstruct Repair { void enqueue(); void drain(); void unused(); };\nusing RepairPtr = std::shared_ptr<Repair>;\nstruct Awaiter { bool await_ready() const noexcept; };\ntemplate <class T> struct Box { Box(); };\ntemplate <> struct Box<void> { Box() {} };\n}\n",
        ),
        (
            "src/repair.cpp",
            "#include \"repair.h\"\n#include <lib/fsm.h>\nnamespace app {\nvoid Repair::enqueue() {}\nvoid Repair::drain() {}\nvoid Repair::unused() {}\nbool Awaiter::await_ready() const noexcept { return true; }\n}\ntemplate <> void lib::Fsm<int>::start() {}\n",
        ),
        (
            "src/use.cpp",
            "#include \"repair.h\"\nnamespace app {\ntemplate <typename Ptr>\nvoid poke(Ptr service) { service->enqueue(); }\nvoid run(RepairPtr repair) { repair->drain(); }\n}\n",
        ),
    ]);
    let found = statuses(model, true);
    // Alias through shared_ptr resolves; the templated receiver keeps enqueue possible.
    assert!(!found.contains_key("drain"), "{found:?}");
    assert_eq!(found["enqueue"].0, "unknown");
    assert!(
        found["enqueue"]
            .1
            .contains(&"unresolved-call-sites".to_owned())
    );
    assert!(
        found["await_ready"]
            .1
            .contains(&"implicit-invocation".to_owned())
    );
    assert!(
        found["start"]
            .1
            .contains(&"outside-class-member".to_owned())
    );
    assert!(found["Box"].1.contains(&"implicit-invocation".to_owned()));
    // Clean negative: nothing can reach unused().
    assert_eq!(found["unused"], ("unreferenced".into(), vec![]));
}