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

use futures::future::BoxFuture;
use futures::future::FutureExt;
use organic::compare::silent_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<ExitCode, Box<dyn std::error::Error>> {
    let rt = tokio::runtime::Runtime::new()?;
    rt.block_on(async {
        let main_body_result = main_body().await;
        main_body_result
    })
}

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

#[cfg_attr(feature = "tracing", tracing::instrument(ret, level = "debug"))]
async fn main_body() -> Result<ExitCode, 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 layer = layer.chain(compare_group("worg", || {
        compare_all_org_document("/foreign_documents/worg")
    }));
    let layer = layer.chain(compare_group("howard_abrams", compare_howard_abrams));
    let layer = layer.chain(compare_group("doomemacs", || {
        compare_all_org_document("/foreign_documents/doomemacs")
    }));
    let layer = layer.chain(compare_group("literate_build_emacs", || {
        compare_all_org_document("/foreign_documents/literate_build_emacs")
    }));

    let running_tests: Vec<_> = layer.map(|c| tokio::spawn(c.run_test())).collect();
    let mut any_failed = false;
    for test in running_tests.into_iter() {
        let test_result = test.await??;
        if test_result.is_immediately_bad() || test_result.has_bad_children() {
            any_failed = true;
        }
        test_result.print();
    }

    if any_failed {
        println!(
            "{color}Some tests failed.{reset}",
            color = TestResult::foreground_color(255, 0, 0),
            reset = TestResult::reset_color(),
        );
        Ok(ExitCode::FAILURE)
    } else {
        println!(
            "{color}All tests passed.{reset}",
            color = TestResult::foreground_color(0, 255, 0),
            reset = TestResult::reset_color(),
        );
        Ok(ExitCode::SUCCESS)
    }
}

fn compare_howard_abrams() -> impl Iterator<Item = TestConfig> {
    let layer = compare_group("dot-files", || {
        compare_all_org_document("/foreign_documents/howardabrams/dot-files")
    });
    let layer = layer.chain(compare_group("hamacs", || {
        compare_all_org_document("/foreign_documents/howardabrams/hamacs")
    }));
    let layer = layer.chain(compare_group("demo-it", || {
        compare_all_org_document("/foreign_documents/howardabrams/demo-it")
    }));
    let layer = layer.chain(compare_group("magit-demo", || {
        compare_all_org_document("/foreign_documents/howardabrams/magit-demo")
    }));
    let layer = layer.chain(compare_group("pdx-emacs-hackers", || {
        compare_all_org_document("/foreign_documents/howardabrams/pdx-emacs-hackers")
    }));
    let layer = layer.chain(compare_group("flora-simulator", || {
        compare_all_org_document("/foreign_documents/howardabrams/flora-simulator")
    }));
    let layer = layer.chain(compare_group("literate-devops-demo", || {
        compare_all_org_document("/foreign_documents/howardabrams/literate-devops-demo")
    }));
    let layer = layer.chain(compare_group("clojure-yesql-xp", || {
        compare_all_org_document("/foreign_documents/howardabrams/clojure-yesql-xp")
    }));
    layer.chain(compare_group("veep", || {
        compare_all_org_document("/foreign_documents/howardabrams/veep")
    }))
}

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 mut 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();
    test_files.sort_by_cached_key(|test_file| PathBuf::from(test_file.path()));
    let test_configs: Vec<_> = test_files
        .into_iter()
        .map(|test_file| {
            let name = test_file
                .path()
                .strip_prefix(root_dir)
                .expect("Result is from walkdir so it must be below the root directory.")
                .as_os_str()
                .to_string_lossy()
                .into_owned();
            TestConfig::SingleFile(SingleFile {
                name,
                file_path: test_file.into_path(),
            })
        })
        .collect();
    test_configs.into_iter()
}

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,
    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 = silent_compare_on_file(&self.file_path).await;
        Ok(SingleFileResult {
            name: self.name,
            status: if let Ok(true) = result {
                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,
        })
    }
}

impl TestResult {
    pub fn print(&self) {
        self.print_indented(0);
    }

    fn print_indented(&self, indentation: usize) {
        match self {
            TestResult::ResultLayer(result) => result.print_indented(indentation),
            TestResult::SingleFileResult(result) => result.print_indented(indentation),
        }
    }

    fn has_bad_children(&self) -> bool {
        match self {
            TestResult::ResultLayer(result) => result.has_bad_children(),
            TestResult::SingleFileResult(result) => result.has_bad_children(),
        }
    }

    fn is_immediately_bad(&self) -> bool {
        match self {
            TestResult::ResultLayer(result) => result.is_immediately_bad(),
            TestResult::SingleFileResult(result) => result.is_immediately_bad(),
        }
    }

    pub(crate) fn foreground_color(red: u8, green: u8, blue: u8) -> String {
        if TestResult::should_use_color() {
            format!(
                "\x1b[38;2;{red};{green};{blue}m",
                red = red,
                green = green,
                blue = blue
            )
        } else {
            String::new()
        }
    }

    #[allow(dead_code)]
    pub(crate) fn background_color(red: u8, green: u8, blue: u8) -> String {
        if TestResult::should_use_color() {
            format!(
                "\x1b[48;2;{red};{green};{blue}m",
                red = red,
                green = green,
                blue = blue
            )
        } else {
            String::new()
        }
    }

    pub(crate) fn reset_color() -> &'static str {
        if TestResult::should_use_color() {
            "\x1b[0m"
        } else {
            ""
        }
    }

    fn should_use_color() -> bool {
        !std::env::var("NO_COLOR").is_ok_and(|val| !val.is_empty())
    }
}

impl SingleFileResult {
    fn print_indented(&self, indentation: usize) {
        match self.status {
            TestStatus::Pass => {
                println!(
                    "{indentation}{color}PASS{reset} {name}",
                    indentation = "  ".repeat(indentation),
                    color = TestResult::foreground_color(0, 255, 0),
                    reset = TestResult::reset_color(),
                    name = self.name
                );
            }
            TestStatus::Fail => {
                println!(
                    "{indentation}{color}FAIL{reset} {name}",
                    indentation = "  ".repeat(indentation),
                    color = TestResult::foreground_color(255, 0, 0),
                    reset = TestResult::reset_color(),
                    name = self.name
                );
            }
        }
    }

    fn has_bad_children(&self) -> bool {
        false
    }

    fn is_immediately_bad(&self) -> bool {
        match self.status {
            TestStatus::Pass => false,
            TestStatus::Fail => true,
        }
    }
}

impl ResultLayer {
    fn print_indented(&self, indentation: usize) {
        if self.is_immediately_bad() {
            println!(
                "{indentation}{color}FAIL{reset} {name}",
                indentation = "  ".repeat(indentation),
                color = TestResult::foreground_color(255, 0, 0),
                reset = TestResult::reset_color(),
                name = self.name
            );
        } else if self.has_bad_children() {
            println!(
                "{indentation}{color}BADCHILD{reset} {name}",
                indentation = "  ".repeat(indentation),
                color = TestResult::foreground_color(255, 255, 0),
                reset = TestResult::reset_color(),
                name = self.name
            );
        } else {
            println!(
                "{indentation}{color}PASS{reset} {name}",
                indentation = "  ".repeat(indentation),
                color = TestResult::foreground_color(0, 255, 0),
                reset = TestResult::reset_color(),
                name = self.name
            );
        }
        self.children
            .iter()
            .for_each(|result| result.print_indented(indentation + 1));
    }

    fn has_bad_children(&self) -> bool {
        self.children
            .iter()
            .any(|result| result.is_immediately_bad() || result.has_bad_children())
    }

    fn is_immediately_bad(&self) -> bool {
        false
    }
}