// error-pattern:yummy
#![feature(box_syntax)]
#![feature(rustc_private)]
#![allow(unknown_lints, missing_docs_in_private_items)]

extern crate clippy_lints;
extern crate getopts;
extern crate rustc;
extern crate rustc_driver;
extern crate rustc_errors;
extern crate rustc_plugin;
extern crate rustc_trans_utils;
extern crate syntax;

use rustc_driver::{driver, Compilation, CompilerCalls, RustcDefaultCalls};
use rustc_trans_utils::trans_crate::TransCrate;
use rustc::session::{config, Session};
use rustc::session::config::{ErrorOutputType, Input};
use std::path::PathBuf;
use std::process::Command;
use syntax::ast;

struct ClippyCompilerCalls {
    default: RustcDefaultCalls,
    run_lints: bool,
}

impl ClippyCompilerCalls {
    fn new(run_lints: bool) -> Self {
        Self {
            default: RustcDefaultCalls,
            run_lints: run_lints,
        }
    }
}

impl<'a> CompilerCalls<'a> for ClippyCompilerCalls {
    fn early_callback(
        &mut self,
        matches: &getopts::Matches,
        sopts: &config::Options,
        cfg: &ast::CrateConfig,
        descriptions: &rustc_errors::registry::Registry,
        output: ErrorOutputType,
    ) -> Compilation {
        self.default
            .early_callback(matches, sopts, cfg, descriptions, output)
    }
    fn no_input(
        &mut self,
        matches: &getopts::Matches,
        sopts: &config::Options,
        cfg: &ast::CrateConfig,
        odir: &Option<PathBuf>,
        ofile: &Option<PathBuf>,
        descriptions: &rustc_errors::registry::Registry,
    ) -> Option<(Input, Option<PathBuf>)> {
        self.default
            .no_input(matches, sopts, cfg, odir, ofile, descriptions)
    }
    fn late_callback(
        &mut self,
        trans_crate: &TransCrate,
        matches: &getopts::Matches,
        sess: &Session,
        crate_stores: &rustc::middle::cstore::CrateStore,
        input: &Input,
        odir: &Option<PathBuf>,
        ofile: &Option<PathBuf>,
    ) -> Compilation {
        self.default
            .late_callback(trans_crate, matches, sess, crate_stores, input, odir, ofile)
    }
    fn build_controller(&mut self, sess: &Session, matches: &getopts::Matches) -> driver::CompileController<'a> {
        let mut control = self.default.build_controller(sess, matches);

        if self.run_lints {
            let old = std::mem::replace(&mut control.after_parse.callback, box |_| {});
            control.after_parse.callback = Box::new(move |state| {
                {
                    let mut registry = rustc_plugin::registry::Registry::new(
                        state.session,
                        state
                            .krate
                            .as_ref()
                            .expect(
                                "at this compilation stage \
                                 the crate must be parsed",
                            )
                            .span,
                    );
                    registry.args_hidden = Some(Vec::new());
                    clippy_lints::register_plugins(&mut registry);

                    let rustc_plugin::registry::Registry {
                        early_lint_passes,
                        late_lint_passes,
                        lint_groups,
                        llvm_passes,
                        attributes,
                        ..
                    } = registry;
                    let sess = &state.session;
                    let mut ls = sess.lint_store.borrow_mut();
                    for pass in early_lint_passes {
                        ls.register_early_pass(Some(sess), true, pass);
                    }
                    for pass in late_lint_passes {
                        ls.register_late_pass(Some(sess), true, pass);
                    }

                    for (name, to) in lint_groups {
                        ls.register_group(Some(sess), true, name, to);
                    }

                    sess.plugin_llvm_passes.borrow_mut().extend(llvm_passes);
                    sess.plugin_attributes.borrow_mut().extend(attributes);
                }
                old(state);
            });
        }

        control
    }
}

#[allow(print_stdout)]
fn show_version() {
    println!("{}", env!("CARGO_PKG_VERSION"));
}

pub fn main() {
    use std::env;

    if std::env::args().any(|a| a == "--version" || a == "-V") {
        show_version();
        return;
    }

    let sys_root = option_env!("SYSROOT")
        .map(String::from)
        .or_else(|| std::env::var("SYSROOT").ok())
        .or_else(|| {
            let home = option_env!("RUSTUP_HOME").or(option_env!("MULTIRUST_HOME"));
            let toolchain = option_env!("RUSTUP_TOOLCHAIN").or(option_env!("MULTIRUST_TOOLCHAIN"));
            home.and_then(|home| toolchain.map(|toolchain| format!("{}/toolchains/{}", home, toolchain)))
        })
        .or_else(|| {
            Command::new("rustc")
                .arg("--print")
                .arg("sysroot")
                .output()
                .ok()
                .and_then(|out| String::from_utf8(out.stdout).ok())
                .map(|s| s.trim().to_owned())
        })
        .expect("need to specify SYSROOT env var during clippy compilation, or use rustup or multirust");

    // Setting RUSTC_WRAPPER causes Cargo to pass 'rustc' as the first argument.
    // We're invoking the compiler programmatically, so we ignore this/
    let mut orig_args: Vec<String> = env::args().collect();
    if orig_args.len() <= 1 {
        std::process::exit(1);
    }
    if orig_args[1] == "rustc" {
        // we still want to be able to invoke it normally though
        orig_args.remove(1);
    }
    // this conditional check for the --sysroot flag is there so users can call
    // `clippy_driver` directly
    // without having to pass --sysroot or anything
    let mut args: Vec<String> = if orig_args.iter().any(|s| s == "--sysroot") {
        orig_args.clone()
    } else {
        orig_args
            .clone()
            .into_iter()
            .chain(Some("--sysroot".to_owned()))
            .chain(Some(sys_root))
            .collect()
    };

    // this check ensures that dependencies are built but not linted and the final
    // crate is
    // linted but not built
    let clippy_enabled = env::var("CLIPPY_TESTS")
        .ok()
        .map_or(false, |val| val == "true")
        || orig_args.iter().any(|s| s == "--emit=metadata");

    if clippy_enabled {
        args.extend_from_slice(&["--cfg".to_owned(), r#"feature="cargo-clippy""#.to_owned()]);
    }

    let mut ccc = ClippyCompilerCalls::new(clippy_enabled);
    rustc_driver::run(move || {
        rustc_driver::run_compiler(&args, &mut ccc, None, None)
    });
}