use brick::model::{Building, EdgeKind, Node, NodeKind};
use brick::scan;
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()
}

fn function<'a>(model: &'a Building, path: &str, name: &str) -> &'a Node {
    model
        .nodes
        .iter()
        .find(|n| n.kind == NodeKind::Function && n.path.as_deref() == Some(path) && n.name == name)
        .unwrap_or_else(|| panic!("missing {path}::{name}"))
}

/// (target parent name, target name, attribute value) for calls leaving `source`.
fn calls(model: &Building, source: &Node, attribute: &str) -> Vec<(String, String, String)> {
    let mut found: Vec<_> = model
        .edges
        .iter()
        .filter(|e| e.kind == EdgeKind::Calls && e.source == source.id)
        .map(|e| {
            let target = model.nodes.iter().find(|n| n.id == e.target).unwrap();
            let parent = target
                .parent
                .as_ref()
                .and_then(|id| model.nodes.iter().find(|n| &n.id == id))
                .map(|n| n.name.clone())
                .unwrap_or_default();
            let value = e
                .attributes
                .get(attribute)
                .and_then(|v| v.as_str())
                .unwrap_or("")
                .to_owned();
            (parent, target.name.clone(), value)
        })
        .collect();
    found.sort();
    found
}

#[test]
fn expression_macro_bodies_yield_calls_and_other_macros_stay_opaque() {
    let model = scan_files(&[(
        "src/lib.rs",
        "fn check() -> bool { true }\nfn name() -> u8 { 0 }\nfn hidden() {}\nmacro_rules! custom { ($e:expr) => { $e } }\nfn run() {\n    assert!(check(), \"{}\", format!(\"{}\", name()));\n    custom!(hidden());\n}\n",
    )]);
    let run = function(&model, "src/lib.rs", "run");
    assert_eq!(
        calls(&model, run, "source.extraction"),
        [
            ("lib.rs".into(), "check".into(), "macro-reparse".into()),
            ("lib.rs".into(), "name".into(), "macro-reparse".into()),
        ]
    );
    let hidden = function(&model, "src/lib.rs", "hidden");
    assert!(
        !model
            .edges
            .iter()
            .any(|e| e.target == hidden.id && e.kind == EdgeKind::Calls)
    );
}

#[test]
fn receivers_resolve_through_self_fields_constructors_and_dyn_traits() {
    let model = scan_files(&[(
        "src/lib.rs",
        "use std::sync::Arc;\npub struct Engine;\nimpl Engine { pub fn commit(&self) {} }\npub trait Named { fn label(&self) -> String; }\npub struct Store { inner: Arc<Engine> }\nimpl Store {\n    pub fn open() -> Result<Self, ()> { Ok(Self::build()) }\n    fn build() -> Self { Store { inner: Arc::new(Engine) } }\n    fn flush(&self) {\n        self.inner.commit();\n        self.log();\n    }\n    fn log(&self) {}\n}\nfn run(item: &dyn Named) -> Result<(), ()> {\n    let store = Store::open()?;\n    store.flush();\n    item.label();\n    Ok(())\n}\n",
    )]);
    let resolved = |source: &Node| {
        calls(&model, source, "source.resolution")
            .into_iter()
            .filter(|(parent, _, _)| !parent.is_empty())
            .collect::<Vec<_>>()
    };
    assert_eq!(
        resolved(function(&model, "src/lib.rs", "flush")),
        [
            (
                "Engine".into(),
                "commit".into(),
                "declared-receiver-type".into()
            ),
            ("Store".into(), "log".into(), "self-receiver".into()),
        ]
    );
    assert_eq!(
        resolved(function(&model, "src/lib.rs", "open")),
        [("Store".into(), "build".into(), "impl-type".into())]
    );
    assert_eq!(
        resolved(function(&model, "src/lib.rs", "run")),
        [
            (
                "Named".into(),
                "label".into(),
                "declared-receiver-type".into()
            ),
            (
                "Store".into(),
                "flush".into(),
                "declared-receiver-type".into()
            ),
            // Same-file `Type::f` already resolves by qualified lookup, unlabeled.
            ("Store".into(), "open".into(), "".into()),
        ]
    );
}

#[test]
fn foreign_imports_generics_and_competing_trait_impls_never_guess() {
    let model = scan_files(&[
        (
            "src/lib.rs",
            "mod local;\nuse std::fs::File;\npub trait Named { fn label(&self) -> String; }\nstruct A;\nstruct B;\nstruct C;\nimpl Named for A { fn label(&self) -> String { String::new() } }\nimpl Named for C { fn label(&self) -> String { String::new() } }\ntrait Other { fn label(&self) -> String; }\nimpl Other for A { fn label(&self) -> String { String::new() } }\nfn run<T: Named>(generic: &T, a: A) {\n    let file = File::open(\"x\").unwrap();\n    file.sync_all();\n    generic.label();\n    a.label();\n}\n",
        ),
        (
            "src/local.rs",
            "pub struct File;\nimpl File {\n    pub fn open(_p: &str) -> Self { File }\n    pub fn sync_all(&self) {}\n}\n",
        ),
    ]);
    let run = function(&model, "src/lib.rs", "run");
    let reasons: Vec<_> = calls(&model, run, "source.unresolved-reason")
        .into_iter()
        .map(|(_, name, reason)| (name, reason))
        .collect();
    assert_eq!(
        reasons,
        [
            ("File::open".into(), "qualifier-unknown".into()),
            ("label".into(), "ambiguous".into()),
            ("label".into(), "receiver-type-unknown".into()),
            ("sync_all".into(), "receiver-type-unknown".into()),
            ("unwrap".into(), "receiver-type-unknown".into()),
        ]
    );
    for name in ["open", "sync_all"] {
        let local = function(&model, "src/local.rs", name);
        assert!(
            !model
                .edges
                .iter()
                .any(|e| e.target == local.id && e.kind == EdgeKind::Calls)
        );
    }
}

#[test]
fn same_named_types_in_different_modules_resolve_through_use_bindings() {
    // Types were keyed by leaf name, so `b::Config` (method from a trait impl) and
    // `a::Config` (inherent method) shared one key and the inherent one won: a call on
    // `b::Config` was attributed to `a::Config::load`.
    let model = scan_files(&[
        ("src/lib.rs", "pub mod a;\npub mod b;\npub mod user;\n"),
        (
            "src/a.rs",
            "pub struct Config;\nimpl Config {\n    pub fn load(&self) -> u32 { 1 }\n}\n",
        ),
        (
            "src/b.rs",
            "pub struct Config;\npub trait Loader { fn load(&self) -> u32; }\nimpl Loader for Config {\n    fn load(&self) -> u32 { 2 }\n}\n",
        ),
        (
            "src/user.rs",
            "use crate::b::Config;\nuse crate::b::Loader;\npub fn run(c: &Config) -> u32 { c.load() }\n",
        ),
        (
            "src/other.rs",
            "pub fn guess(c: &Config) -> u32 { c.load() }\n",
        ),
    ]);
    let targets = |source: &Node| {
        model
            .edges
            .iter()
            .filter(|e| e.kind == EdgeKind::Calls && e.source == source.id)
            .map(|e| {
                let target = model.nodes.iter().find(|n| n.id == e.target).unwrap();
                (
                    target.path.clone().unwrap_or_default(),
                    e.attributes
                        .get("source.unresolved-reason")
                        .and_then(|v| v.as_str())
                        .unwrap_or("")
                        .to_owned(),
                )
            })
            .collect::<Vec<_>>()
    };
    let run = function(&model, "src/user.rs", "run");
    assert_eq!(targets(run), [("src/b.rs".to_owned(), String::new())]);
    // Without a binding, two same-named types leave the call ambiguous, not guessed.
    let guess = function(&model, "src/other.rs", "guess");
    assert_eq!(targets(guess), [(String::new(), "ambiguous".to_owned())]);
}

#[test]
fn an_impl_on_a_qualified_path_in_another_file_keeps_its_methods() {
    // With several files declaring `Foo`, an impl was kept only if its own file
    // resolved `Foo`; `impl crate::a::Foo` in a third file resolved nothing and its
    // methods were dropped, so the call read "member-not-found".
    let model = scan_files(&[
        (
            "src/lib.rs",
            "pub mod a;\npub mod c;\npub mod ext;\npub mod main_use;\n",
        ),
        ("src/a.rs", "pub struct Foo;\n"),
        ("src/c.rs", "pub struct Foo;\n"),
        (
            "src/ext.rs",
            "impl crate::a::Foo {\n    pub fn run(&self) {}\n}\n",
        ),
        (
            "src/main_use.rs",
            "use crate::a::Foo;\npub fn f(x: Foo) {\n    x.run();\n}\n",
        ),
    ]);
    let caller = function(&model, "src/main_use.rs", "f");
    let targets = calls(&model, caller, "source.resolution");
    assert!(
        targets.iter().any(|(_, name, _)| name == "run"),
        "{targets:?}"
    );
    let run = function(&model, "src/ext.rs", "run");
    assert!(
        model
            .edges
            .iter()
            .any(|e| e.kind == EdgeKind::Calls && e.source == caller.id && e.target == run.id)
    );
}