// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.

use crate::{
    Encoding, LanguageService, UpdateWorker,
    protocol::{DiagnosticUpdate, ErrorKind, TestCallables},
};
use expect_test::{Expect, expect};
use qsc::{compile, line_column::Position, project};
use std::{cell::RefCell, rc::Rc};
use test_fs::{FsNode, TestProjectHost, dir, file};

pub(crate) mod test_fs;

#[tokio::test]
async fn single_document() {
    let received_errors = RefCell::new(Vec::new());
    let test_cases = RefCell::new(Vec::new());
    let mut ls = LanguageService::new(Encoding::Utf8);
    let mut worker = create_update_worker(&mut ls, &received_errors, &test_cases);

    ls.update_document("foo.qs", 1, "namespace Foo { }", "qsharp");

    worker.apply_pending().await;

    check_errors_and_compilation(
        &ls,
        &mut received_errors.borrow_mut(),
        "foo.qs",
        &(expect![[r#"
            []
        "#]]),
        &(expect![[r#"
            SourceMap {
                sources: [
                    Source {
                        name: "foo.qs",
                        contents: "namespace Foo { }",
                        offset: 0,
                    },
                ],
                common_prefix: None,
                entry: None,
            }
        "#]]),
    );
}

#[tokio::test]
#[allow(clippy::too_many_lines)]
async fn single_document_update() {
    let received_errors = RefCell::new(Vec::new());
    let test_cases = RefCell::new(Vec::new());
    let mut ls = LanguageService::new(Encoding::Utf8);
    let mut worker = create_update_worker(&mut ls, &received_errors, &test_cases);

    ls.update_document("foo.qs", 1, "namespace Foo { }", "qsharp");

    worker.apply_pending().await;

    check_errors_and_compilation(
        &ls,
        &mut received_errors.borrow_mut(),
        "foo.qs",
        &(expect![[r#"
            []
        "#]]),
        &(expect![[r#"
            SourceMap {
                sources: [
                    Source {
                        name: "foo.qs",
                        contents: "namespace Foo { }",
                        offset: 0,
                    },
                ],
                common_prefix: None,
                entry: None,
            }
        "#]]),
    );

    // UPDATE 2
    ls.update_document(
        "foo.qs",
        1,
        "namespace Foo { @EntryPoint() operation Bar() : Unit {} }",
        "qsharp",
    );

    worker.apply_pending().await;

    check_errors_and_compilation(
        &ls,
        &mut received_errors.borrow_mut(),
        "foo.qs",
        &(expect![[r#"
            []
        "#]]),
        &(expect![[r#"
            SourceMap {
                sources: [
                    Source {
                        name: "foo.qs",
                        contents: "namespace Foo { @EntryPoint() operation Bar() : Unit {} }",
                        offset: 0,
                    },
                ],
                common_prefix: None,
                entry: None,
            }
        "#]]),
    );
}

#[tokio::test]
#[allow(clippy::too_many_lines)]
async fn document_in_project() {
    let received_errors = RefCell::new(Vec::new());
    let test_cases = RefCell::new(Vec::new());
    let mut ls = LanguageService::new(Encoding::Utf8);
    let mut worker = create_update_worker(&mut ls, &received_errors, &test_cases);

    ls.update_document("project/src/this_file.qs", 1, "namespace Foo { }", "qsharp");

    check_errors_and_no_compilation(
        &ls,
        &mut received_errors.borrow_mut(),
        "project/src/this_file.qs",
        &(expect![[r#"
            []
        "#]]),
    );

    // now process background work
    worker.apply_pending().await;

    check_errors_and_compilation(
        &ls,
        &mut received_errors.borrow_mut(),
        "project/src/this_file.qs",
        &expect![[r#"
            []
        "#]],
        &expect![[r#"
            SourceMap {
                sources: [
                    Source {
                        name: "project/src/other_file.qs",
                        contents: "namespace OtherFile { operation Other() : Unit {} }",
                        offset: 0,
                    },
                    Source {
                        name: "project/src/this_file.qs",
                        contents: "namespace Foo { }",
                        offset: 52,
                    },
                ],
                common_prefix: Some(
                    "project/src/",
                ),
                entry: None,
            }
        "#]],
    );
}

// the below tests test the asynchronous behavior of the language service.
// we use `get_completions` as a rough analog for all document operations, as
// they all go through the same `document_op` infrastructure.
#[tokio::test]
async fn completions_requested_before_document_load() {
    let errors = RefCell::new(Vec::new());
    let test_cases = RefCell::new(Vec::new());
    let mut ls = LanguageService::new(Encoding::Utf8);
    let _worker = create_update_worker(&mut ls, &errors, &test_cases);

    ls.update_document(
        "foo.qs",
        1,
        "namespace Foo { open Microsoft.Quantum.Diagnostics; @EntryPoint() operation Main() : Unit { DumpMachine() } }",
        "qsharp"
    );

    // we intentionally don't await work to test how LSP features function when
    // a document hasn't fully loaded

    // this should be empty, because the doc hasn't loaded
    assert!(
        ls.get_completions(
            "foo.qs",
            Position {
                line: 0,
                column: 76
            }
        )
        .items
        .is_empty()
    );
}

#[tokio::test]
async fn completions_requested_after_document_load() {
    let errors = RefCell::new(Vec::new());
    let test_cases = RefCell::new(Vec::new());
    let mut ls = LanguageService::new(Encoding::Utf8);
    let mut worker = create_update_worker(&mut ls, &errors, &test_cases);

    // this test is a contrast to `completions_requested_before_document_load`
    // we want to ensure that completions load when the update_document call has been awaited
    ls.update_document(
        "foo.qs",
        1,
        "namespace Foo { open Microsoft.Quantum.Diagnostics; @EntryPoint() operation Main() : Unit { DumpMachine() } }",
        "qsharp"
    );

    worker.apply_pending().await;

    assert!(
        &ls.get_completions(
            "foo.qs",
            Position {
                line: 0,
                column: 92,
            },
        )
        .items
        .iter()
        .any(|item| item.label == "DumpMachine")
    );
}

fn check_errors_and_compilation(
    ls: &LanguageService,
    received_errors: &mut Vec<ErrorInfo>,
    uri: &str,
    expected_errors: &Expect,
    expected_compilation: &Expect,
) {
    expected_errors.assert_debug_eq(received_errors);
    assert_compilation(ls, uri, expected_compilation);
    received_errors.clear();
}

fn check_errors_and_no_compilation(
    ls: &LanguageService,
    received_errors: &mut Vec<ErrorInfo>,
    uri: &str,
    expected_errors: &Expect,
) {
    expected_errors.assert_debug_eq(received_errors);
    received_errors.clear();

    let state = ls.state.try_borrow().expect("borrow should succeed");
    assert!(state.get_compilation(uri).is_none());
}

fn assert_compilation(ls: &LanguageService, uri: &str, expected: &Expect) {
    let state = ls.state.try_borrow().expect("borrow should succeed");
    let compilation = state
        .get_compilation(uri)
        .expect("compilation should exist");
    expected.assert_debug_eq(&compilation.user_unit().sources);
}

type ErrorInfo = (
    String,
    Option<u32>,
    Vec<compile::ErrorKind>,
    Vec<project::Error>,
);

fn create_update_worker<'a>(
    ls: &mut LanguageService,
    received_errors: &'a RefCell<Vec<ErrorInfo>>,
    received_test_cases: &'a RefCell<Vec<TestCallables>>,
) -> UpdateWorker<'a> {
    ls.create_update_worker(
        |update: DiagnosticUpdate| {
            let project_errors = update.errors.iter().filter_map(|error| match error {
                ErrorKind::Project(error) => Some(error.clone()),
                ErrorKind::Compile(_)
                | ErrorKind::DocumentStatus { .. }
                | ErrorKind::Unnecessary(_) => None,
            });
            let compile_errors = update.errors.iter().filter_map(|error| match error {
                ErrorKind::Compile(error) => Some(error.error().clone()),
                ErrorKind::Project(_)
                | ErrorKind::DocumentStatus { .. }
                | ErrorKind::Unnecessary(_) => None,
            });

            let mut v = received_errors.borrow_mut();

            v.push((
                update.uri,
                update.version,
                compile_errors.collect(),
                project_errors.collect(),
            ));
        },
        move |update: TestCallables| {
            let mut v = received_test_cases.borrow_mut();
            v.push(update);
        },
        TestProjectHost {
            fs: TEST_FS.with(Clone::clone),
        },
    )
}

thread_local! { static TEST_FS: Rc<RefCell<FsNode>> = Rc::new(RefCell::new(test_fs())) }

fn test_fs() -> FsNode {
    FsNode::Dir(
        [dir(
            "project",
            [
                file("qsharp.json", "{}"),
                dir(
                    "src",
                    [
                        file(
                            "other_file.qs",
                            "namespace OtherFile { operation Other() : Unit {} }",
                        ),
                        file("this_file.qs", "namespace Foo { }"),
                    ],
                ),
            ],
        )]
        .into_iter()
        .collect(),
    )
}
