//! Database used for testing `hir`.

use std::{
    panic,
    sync::{Arc, Mutex},
};

use hir_def::{db::DefDatabase, AssocItemId, ModuleDefId, ModuleId};
use hir_expand::diagnostics::DiagnosticSink;
use ra_db::{salsa, CrateId, FileId, FileLoader, FileLoaderDelegate, RelativePath, SourceDatabase};

use crate::{db::HirDatabase, expr::ExprValidator};

#[salsa::database(
    ra_db::SourceDatabaseExtStorage,
    ra_db::SourceDatabaseStorage,
    hir_expand::db::AstDatabaseStorage,
    hir_def::db::InternDatabaseStorage,
    hir_def::db::DefDatabaseStorage,
    crate::db::HirDatabaseStorage
)]
#[derive(Debug, Default)]
pub struct TestDB {
    events: Mutex<Option<Vec<salsa::Event<TestDB>>>>,
    runtime: salsa::Runtime<TestDB>,
}

impl salsa::Database for TestDB {
    fn salsa_runtime(&self) -> &salsa::Runtime<TestDB> {
        &self.runtime
    }

    fn salsa_runtime_mut(&mut self) -> &mut salsa::Runtime<Self> {
        &mut self.runtime
    }

    fn salsa_event(&self, event: impl Fn() -> salsa::Event<TestDB>) {
        let mut events = self.events.lock().unwrap();
        if let Some(events) = &mut *events {
            events.push(event());
        }
    }
}

impl salsa::ParallelDatabase for TestDB {
    fn snapshot(&self) -> salsa::Snapshot<TestDB> {
        salsa::Snapshot::new(TestDB {
            events: Default::default(),
            runtime: self.runtime.snapshot(self),
        })
    }
}

impl panic::RefUnwindSafe for TestDB {}

impl FileLoader for TestDB {
    fn file_text(&self, file_id: FileId) -> Arc<String> {
        FileLoaderDelegate(self).file_text(file_id)
    }
    fn resolve_relative_path(
        &self,
        anchor: FileId,
        relative_path: &RelativePath,
    ) -> Option<FileId> {
        FileLoaderDelegate(self).resolve_relative_path(anchor, relative_path)
    }
    fn relevant_crates(&self, file_id: FileId) -> Arc<Vec<CrateId>> {
        FileLoaderDelegate(self).relevant_crates(file_id)
    }
}

impl TestDB {
    pub fn module_for_file(&self, file_id: FileId) -> ModuleId {
        for &krate in self.relevant_crates(file_id).iter() {
            let crate_def_map = self.crate_def_map(krate);
            for (module_id, data) in crate_def_map.modules.iter() {
                if data.definition == Some(file_id) {
                    return ModuleId { krate, module_id };
                }
            }
        }
        panic!("Can't find module for file")
    }

    // FIXME: don't duplicate this
    pub fn diagnostics(&self) -> String {
        let mut buf = String::new();
        let crate_graph = self.crate_graph();
        for krate in crate_graph.iter().next() {
            let crate_def_map = self.crate_def_map(krate);

            let mut fns = Vec::new();
            for (module_id, _) in crate_def_map.modules.iter() {
                for decl in crate_def_map[module_id].scope.declarations() {
                    match decl {
                        ModuleDefId::FunctionId(f) => fns.push(f),
                        _ => (),
                    }
                }

                for &impl_id in crate_def_map[module_id].impls.iter() {
                    let impl_data = self.impl_data(impl_id);
                    for item in impl_data.items.iter() {
                        if let AssocItemId::FunctionId(f) = item {
                            fns.push(*f)
                        }
                    }
                }
            }

            for f in fns {
                let infer = self.infer(f.into());
                let mut sink = DiagnosticSink::new(|d| {
                    buf += &format!("{:?}: {}\n", d.syntax_node(self).text(), d.message());
                });
                infer.add_diagnostics(self, f, &mut sink);
                let mut validator = ExprValidator::new(f, infer, &mut sink);
                validator.validate_body(self);
            }
        }
        buf
    }
}

impl TestDB {
    pub fn log(&self, f: impl FnOnce()) -> Vec<salsa::Event<TestDB>> {
        *self.events.lock().unwrap() = Some(Vec::new());
        f();
        self.events.lock().unwrap().take().unwrap()
    }

    pub fn log_executed(&self, f: impl FnOnce()) -> Vec<String> {
        let events = self.log(f);
        events
            .into_iter()
            .filter_map(|e| match e.kind {
                // This pretty horrible, but `Debug` is the only way to inspect
                // QueryDescriptor at the moment.
                salsa::EventKind::WillExecute { database_key } => {
                    Some(format!("{:?}", database_key))
                }
                _ => None,
            })
            .collect()
    }
}