extern crate backtrace;

use backtrace::Frame;
use std::thread;

static LIBUNWIND: bool = cfg!(all(unix, feature = "libunwind"));
static UNIX_BACKTRACE: bool = cfg!(all(unix, feature = "unix-backtrace"));
static LIBBACKTRACE: bool = cfg!(feature = "libbacktrace")
    && !cfg!(target_os = "fuchsia");
static CORESYMBOLICATION: bool = cfg!(all(
    any(target_os = "macos", target_os = "ios"),
    feature = "coresymbolication"
));
static DLADDR: bool = cfg!(all(unix, feature = "dladdr")) && !cfg!(target_os = "fuchsia");
static DBGHELP: bool = cfg!(all(windows, feature = "dbghelp"));
static MSVC: bool = cfg!(target_env = "msvc");
static GIMLI_SYMBOLIZE: bool = cfg!(all(feature = "gimli-symbolize", unix, target_os = "linux"));

#[test]
// FIXME: shouldn't ignore this test on i686-msvc, unsure why it's failing
#[cfg_attr(all(target_arch = "x86", target_env = "msvc"), ignore)]
#[rustfmt::skip] // we care about line numbers here
fn smoke_test_frames() {
    frame_1(line!());
    #[inline(never)] fn frame_1(start_line: u32) { frame_2(start_line) }
    #[inline(never)] fn frame_2(start_line: u32) { frame_3(start_line) }
    #[inline(never)] fn frame_3(start_line: u32) { frame_4(start_line) }
    #[inline(never)] fn frame_4(start_line: u32) {
        let mut v = Vec::new();
        backtrace::trace(|cx| {
            v.push(cx.clone());
            true
        });

        if v.len() < 5 {
            assert!(!LIBUNWIND);
            assert!(!UNIX_BACKTRACE);
            assert!(!DBGHELP);
            return;
        }

        // Various platforms have various bits of weirdness about their
        // backtraces. To find a good starting spot let's search through the
        // frames
        let target = frame_4 as usize;
        let offset = v
            .iter()
            .map(|frame| frame.symbol_address() as usize)
            .enumerate()
            .filter_map(|(i, sym)| {
                if sym >= target {
                    Some((sym, i))
                } else {
                    None
                }
            })
            .min()
            .unwrap()
            .1;
        let mut frames = v[offset..].iter();

        assert_frame(
            frames.next().unwrap(),
            frame_4 as usize,
            "frame_4",
            "tests/smoke.rs",
            start_line + 6,
        );
        assert_frame(
            frames.next().unwrap(),
            frame_3 as usize,
            "frame_3",
            "tests/smoke.rs",
            start_line + 3,
        );
        assert_frame(
            frames.next().unwrap(),
            frame_2 as usize,
            "frame_2",
            "tests/smoke.rs",
            start_line + 2,
        );
        assert_frame(
            frames.next().unwrap(),
            frame_1 as usize,
            "frame_1",
            "tests/smoke.rs",
            start_line + 1,
        );
        assert_frame(
            frames.next().unwrap(),
            smoke_test_frames as usize,
            "smoke_test_frames",
            "",
            0,
        );
    }

    fn assert_frame(
        frame: &Frame,
        actual_fn_pointer: usize,
        expected_name: &str,
        expected_file: &str,
        expected_line: u32,
    ) {
        let ip = frame.ip() as usize;
        let sym = frame.symbol_address() as usize;
        assert!(ip >= sym);
        assert!(sym >= actual_fn_pointer);

        // windows dbghelp is *quite* liberal (and wrong) in many of its reports
        // right now...
        //
        // This assertion can also fail for release builds, so skip it there
        if !DBGHELP && cfg!(debug_assertions) {
            assert!(sym - actual_fn_pointer < 1024);
        }

        let mut resolved = 0;
        let can_resolve = DLADDR || LIBBACKTRACE || CORESYMBOLICATION || DBGHELP || GIMLI_SYMBOLIZE;

        let mut name = None;
        let mut addr = None;
        let mut line = None;
        let mut file = None;
        backtrace::resolve_frame(frame, |sym| {
            resolved += 1;
            name = sym.name().map(|v| v.to_string());
            addr = sym.addr();
            line = sym.lineno();
            file = sym.filename().map(|v| v.to_path_buf());
            println!("  sym: {:?}", name);
        });

        // dbghelp doesn't always resolve symbols right now
        match resolved {
            0 => return assert!(!can_resolve || DBGHELP),
            _ => {}
        }

        // * linux dladdr doesn't work (only consults local symbol table)
        // * windows dbghelp isn't great for GNU
        if can_resolve && !(cfg!(target_os = "linux") && DLADDR) && !(DBGHELP && !MSVC) {
            let name = name.expect("didn't find a name");

            // in release mode names get weird as functions can get merged
            // together with `mergefunc`, so only assert this in debug mode
            if cfg!(debug_assertions) {
                assert!(
                    name.contains(expected_name),
                    "didn't find `{}` in `{}`",
                    expected_name,
                    name
                );
            }
        }

        if can_resolve {
            addr.expect("didn't find a symbol");
        }

        if (LIBBACKTRACE || CORESYMBOLICATION || (DBGHELP && MSVC)) && cfg!(debug_assertions) {
            let line = line.expect("didn't find a line number");
            let file = file.expect("didn't find a line number");
            if !expected_file.is_empty() {
                assert!(
                    file.ends_with(expected_file),
                    "{:?} didn't end with {:?}",
                    file,
                    expected_file
                );
            }
            if expected_line != 0 {
                assert!(
                    line == expected_line,
                    "bad line number on frame for `{}`: {} != {}",
                    expected_name,
                    line,
                    expected_line
                );
            }
        }
    }
}

#[test]
fn many_threads() {
    let threads = (0..16)
        .map(|_| {
            thread::spawn(|| {
                for _ in 0..16 {
                    backtrace::trace(|frame| {
                        backtrace::resolve(frame.ip(), |symbol| {
                            let _s = symbol.name().map(|s| s.to_string());
                        });
                        true
                    });
                }
            })
        })
        .collect::<Vec<_>>();

    for t in threads {
        t.join().unwrap()
    }
}

#[test]
#[cfg(feature = "rustc-serialize")]
fn is_rustc_serialize() {
    extern crate rustc_serialize;

    fn is_encode<T: rustc_serialize::Encodable>() {}
    fn is_decode<T: rustc_serialize::Decodable>() {}

    is_encode::<backtrace::Backtrace>();
    is_decode::<backtrace::Backtrace>();
}

#[test]
#[cfg(feature = "serde")]
fn is_serde() {
    extern crate serde;

    fn is_serialize<T: serde::ser::Serialize>() {}
    fn is_deserialize<T: serde::de::DeserializeOwned>() {}

    is_serialize::<backtrace::Backtrace>();
    is_deserialize::<backtrace::Backtrace>();
}
