#![feature(round_char_boundary)]
#![feature(exact_size_is_empty)]
use std::io::Read;
use std::path::Path;
use std::path::PathBuf;

use futures::future::BoxFuture;
use futures::future::FutureExt;
use organic::compare::run_anonymous_compare;
use organic::compare::run_compare_on_file;
use tokio::sync::Semaphore;
use tokio::task::JoinError;
use walkdir::WalkDir;

#[cfg(feature = "tracing")]
use crate::init_tracing::init_telemetry;
#[cfg(feature = "tracing")]
use crate::init_tracing::shutdown_telemetry;
#[cfg(feature = "tracing")]
mod init_tracing;

#[cfg(not(feature = "tracing"))]
fn main() -> Result<(), Box<dyn std::error::Error>> {
    let rt = tokio::runtime::Runtime::new()?;
    let result = rt.block_on(async {
        let main_body_result = main_body().await;
        main_body_result
    });
    result
}

#[cfg(feature = "tracing")]
fn main() -> Result<(), Box<dyn std::error::Error>> {
    let rt = tokio::runtime::Runtime::new()?;
    let result = rt.block_on(async {
        init_telemetry()?;
        let main_body_result = main_body().await;
        shutdown_telemetry()?;
        main_body_result
    });
    result
}

#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
async fn main_body() -> Result<(), Box<dyn std::error::Error>> {
    let layer = compare_group("org-mode", || {
        compare_all_org_document("/foreign_documents/org-mode")
    });
    let layer = layer.chain(compare_group("emacs", || {
        compare_all_org_document("/foreign_documents/emacs")
    }));

    let running_tests: Vec<_> = layer.map(|c| tokio::spawn(c.run_test())).collect();
    for test in running_tests.into_iter() {
        let test_result = test.await??;
        println!("{:?}", test_result);
    }

    Ok(())
}

fn compare_group<N: Into<String>, F: Fn() -> I, I: Iterator<Item = TestConfig>>(
    name: N,
    inner: F,
) -> impl Iterator<Item = TestConfig> {
    std::iter::once(TestConfig::TestLayer(TestLayer {
        name: name.into(),
        children: inner().collect(),
    }))
}

fn compare_all_org_document<P: AsRef<Path>>(root_dir: P) -> impl Iterator<Item = TestConfig> {
    let root_dir = root_dir.as_ref();
    let test_files = WalkDir::new(root_dir)
        .into_iter()
        .filter(|e| match e {
            Ok(dir_entry) => {
                dir_entry.file_type().is_file()
                    && Path::new(dir_entry.file_name())
                        .extension()
                        .map(|ext| ext.to_ascii_lowercase() == "org")
                        .unwrap_or(false)
            }
            Err(_) => true,
        })
        .collect::<Result<Vec<_>, _>>()
        .unwrap();
    let test_configs = test_files.into_iter().map(|test_file| {
        let name = test_file.path().as_os_str().to_string_lossy().into_owned();
        TestConfig::SingleFile(SingleFile {
            name,
            file_path: test_file.into_path(),
        })
    });
    test_configs
}

static TEST_PERMITS: Semaphore = Semaphore::const_new(8);

#[derive(Debug)]
enum TestConfig {
    TestLayer(TestLayer),
    SingleFile(SingleFile),
}

#[derive(Debug)]
struct TestLayer {
    name: String,
    children: Vec<TestConfig>,
}

#[derive(Debug)]
struct SingleFile {
    name: String,
    file_path: PathBuf,
}

#[derive(Debug)]
enum TestResult {
    ResultLayer(ResultLayer),
    SingleFileResult(SingleFileResult),
}

#[derive(Debug)]
struct ResultLayer {
    name: String,
    children: Vec<TestResult>,
}

#[derive(Debug)]
struct SingleFileResult {
    name: String,
    file_path: PathBuf,
    status: TestStatus,
}

#[derive(Debug)]
pub(crate) enum TestStatus {
    Pass,
    Fail,
}

impl TestConfig {
    fn run_test(self) -> BoxFuture<'static, Result<TestResult, JoinError>> {
        async move {
            match self {
                TestConfig::TestLayer(test) => Ok(TestResult::ResultLayer(test.run_test().await?)),
                TestConfig::SingleFile(test) => {
                    Ok(TestResult::SingleFileResult(test.run_test().await?))
                }
            }
        }
        .boxed()
    }
}

impl SingleFile {
    async fn run_test(self) -> Result<SingleFileResult, JoinError> {
        let _permit = TEST_PERMITS.acquire().await.unwrap();
        let result = run_compare_on_file(&self.file_path);
        Ok(SingleFileResult {
            name: self.name,
            file_path: self.file_path,
            status: if result.is_ok() {
                TestStatus::Pass
            } else {
                TestStatus::Fail
            },
        })
    }
}

impl TestLayer {
    async fn run_test(self) -> Result<ResultLayer, JoinError> {
        let running_children: Vec<_> = self
            .children
            .into_iter()
            .map(|c| tokio::spawn(c.run_test()))
            .collect();
        let mut children = Vec::with_capacity(running_children.len());
        for c in running_children {
            children.push(c.await??);
        }
        Ok(ResultLayer {
            name: self.name,
            children,
        })
    }
}