#![allow(unknown_lints)]

use std::fmt;
use std::path::PathBuf;
use std::process::{ExitStatus, Output};
use std::str;

use clap;
use failure::{Context, Error, Fail};
use log::trace;

use crate::core::{TargetKind, Workspace};
use crate::ops::CompileOptions;

pub type CargoResult<T> = failure::Fallible<T>; // Alex's body isn't quite ready to give up "Result"

pub trait CargoResultExt<T, E> {
    fn chain_err<F, D>(self, f: F) -> Result<T, Context<D>>
    where
        F: FnOnce() -> D,
        D: fmt::Display + Send + Sync + 'static;
}

impl<T, E> CargoResultExt<T, E> for Result<T, E>
where
    E: Into<Error>,
{
    fn chain_err<F, D>(self, f: F) -> Result<T, Context<D>>
    where
        F: FnOnce() -> D,
        D: fmt::Display + Send + Sync + 'static,
    {
        self.map_err(|failure| {
            let err = failure.into();
            let context = f();
            trace!("error: {}", err);
            trace!("\tcontext: {}", context);
            err.context(context)
        })
    }
}

#[derive(Debug, Fail)]
#[fail(display = "failed to get 200 response from `{}`, got {}", url, code)]
pub struct HttpNot200 {
    pub code: u32,
    pub url: String,
}

pub struct Internal {
    inner: Error,
}

impl Internal {
    pub fn new(inner: Error) -> Internal {
        Internal { inner }
    }
}

impl Fail for Internal {
    fn cause(&self) -> Option<&dyn Fail> {
        self.inner.as_fail().cause()
    }
}

impl fmt::Debug for Internal {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        self.inner.fmt(f)
    }
}

impl fmt::Display for Internal {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        self.inner.fmt(f)
    }
}

/// Error wrapper related to a particular manifest and providing it's path.
///
/// This error adds no displayable info of it's own.
pub struct ManifestError {
    cause: Error,
    manifest: PathBuf,
}

impl ManifestError {
    pub fn new<E: Into<Error>>(cause: E, manifest: PathBuf) -> Self {
        Self {
            cause: cause.into(),
            manifest,
        }
    }

    pub fn manifest_path(&self) -> &PathBuf {
        &self.manifest
    }

    /// Returns an iterator over the `ManifestError` chain of causes.
    ///
    /// So if this error was not caused by another `ManifestError` this will be empty.
    pub fn manifest_causes(&self) -> ManifestCauses<'_> {
        ManifestCauses { current: self }
    }
}

impl Fail for ManifestError {
    fn cause(&self) -> Option<&dyn Fail> {
        self.cause.as_fail().cause()
    }
}

impl fmt::Debug for ManifestError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        self.cause.fmt(f)
    }
}

impl fmt::Display for ManifestError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        self.cause.fmt(f)
    }
}

/// An iterator over the `ManifestError` chain of causes.
pub struct ManifestCauses<'a> {
    current: &'a ManifestError,
}

impl<'a> Iterator for ManifestCauses<'a> {
    type Item = &'a ManifestError;

    fn next(&mut self) -> Option<Self::Item> {
        self.current = self.current.cause.downcast_ref()?;
        Some(self.current)
    }
}

impl<'a> ::std::iter::FusedIterator for ManifestCauses<'a> {}

// =============================================================================
// Process errors
#[derive(Debug, Fail)]
#[fail(display = "{}", desc)]
pub struct ProcessError {
    pub desc: String,
    pub exit: Option<ExitStatus>,
    pub output: Option<Output>,
}

// =============================================================================
// Cargo test errors.

/// Error when testcases fail
#[derive(Debug, Fail)]
#[fail(display = "{}", desc)]
pub struct CargoTestError {
    pub test: Test,
    pub desc: String,
    pub exit: Option<ExitStatus>,
    pub causes: Vec<ProcessError>,
}

#[derive(Debug)]
pub enum Test {
    Multiple,
    Doc,
    UnitTest {
        kind: TargetKind,
        name: String,
        pkg_name: String,
    },
}

impl CargoTestError {
    pub fn new(test: Test, errors: Vec<ProcessError>) -> Self {
        if errors.is_empty() {
            panic!("Cannot create CargoTestError from empty Vec")
        }
        let desc = errors
            .iter()
            .map(|error| error.desc.clone())
            .collect::<Vec<String>>()
            .join("\n");
        CargoTestError {
            test,
            desc,
            exit: errors[0].exit,
            causes: errors,
        }
    }

    pub fn hint(&self, ws: &Workspace<'_>, opts: &CompileOptions<'_>) -> String {
        match self.test {
            Test::UnitTest {
                ref kind,
                ref name,
                ref pkg_name,
            } => {
                let pkg_info = if opts.spec.needs_spec_flag(ws) {
                    format!("-p {} ", pkg_name)
                } else {
                    String::new()
                };

                match *kind {
                    TargetKind::Bench => {
                        format!("test failed, to rerun pass '{}--bench {}'", pkg_info, name)
                    }
                    TargetKind::Bin => {
                        format!("test failed, to rerun pass '{}--bin {}'", pkg_info, name)
                    }
                    TargetKind::Lib(_) => format!("test failed, to rerun pass '{}--lib'", pkg_info),
                    TargetKind::Test => {
                        format!("test failed, to rerun pass '{}--test {}'", pkg_info, name)
                    }
                    TargetKind::ExampleBin | TargetKind::ExampleLib(_) => {
                        format!("test failed, to rerun pass '{}--example {}", pkg_info, name)
                    }
                    _ => "test failed.".into(),
                }
            }
            Test::Doc => "test failed, to rerun pass '--doc'".into(),
            _ => "test failed.".into(),
        }
    }
}

// =============================================================================
// CLI errors

pub type CliResult = Result<(), CliError>;

#[derive(Debug)]
pub struct CliError {
    pub error: Option<failure::Error>,
    pub unknown: bool,
    pub exit_code: i32,
}

impl CliError {
    pub fn new(error: failure::Error, code: i32) -> CliError {
        let unknown = error.downcast_ref::<Internal>().is_some();
        CliError {
            error: Some(error),
            exit_code: code,
            unknown,
        }
    }

    pub fn code(code: i32) -> CliError {
        CliError {
            error: None,
            exit_code: code,
            unknown: false,
        }
    }
}

impl From<failure::Error> for CliError {
    fn from(err: failure::Error) -> CliError {
        CliError::new(err, 101)
    }
}

impl From<clap::Error> for CliError {
    fn from(err: clap::Error) -> CliError {
        let code = if err.use_stderr() { 1 } else { 0 };
        CliError::new(err.into(), code)
    }
}

// =============================================================================
// Construction helpers

pub fn process_error(
    msg: &str,
    status: Option<ExitStatus>,
    output: Option<&Output>,
) -> ProcessError {
    let exit = match status {
        Some(s) => status_to_string(s),
        None => "never executed".to_string(),
    };
    let mut desc = format!("{} ({})", &msg, exit);

    if let Some(out) = output {
        match str::from_utf8(&out.stdout) {
            Ok(s) if !s.trim().is_empty() => {
                desc.push_str("\n--- stdout\n");
                desc.push_str(s);
            }
            Ok(..) | Err(..) => {}
        }
        match str::from_utf8(&out.stderr) {
            Ok(s) if !s.trim().is_empty() => {
                desc.push_str("\n--- stderr\n");
                desc.push_str(s);
            }
            Ok(..) | Err(..) => {}
        }
    }

    return ProcessError {
        desc,
        exit: status,
        output: output.cloned(),
    };

    #[cfg(unix)]
    fn status_to_string(status: ExitStatus) -> String {
        use std::os::unix::process::*;

        if let Some(signal) = status.signal() {
            let name = match signal as libc::c_int {
                libc::SIGABRT => ", SIGABRT: process abort signal",
                libc::SIGALRM => ", SIGALRM: alarm clock",
                libc::SIGFPE => ", SIGFPE: erroneous arithmetic operation",
                libc::SIGHUP => ", SIGHUP: hangup",
                libc::SIGILL => ", SIGILL: illegal instruction",
                libc::SIGINT => ", SIGINT: terminal interrupt signal",
                libc::SIGKILL => ", SIGKILL: kill",
                libc::SIGPIPE => ", SIGPIPE: write on a pipe with no one to read",
                libc::SIGQUIT => ", SIGQUIT: terminal quite signal",
                libc::SIGSEGV => ", SIGSEGV: invalid memory reference",
                libc::SIGTERM => ", SIGTERM: termination signal",
                libc::SIGBUS => ", SIGBUS: access to undefined memory",
                #[cfg(not(target_os = "haiku"))]
                libc::SIGSYS => ", SIGSYS: bad system call",
                libc::SIGTRAP => ", SIGTRAP: trace/breakpoint trap",
                _ => "",
            };
            format!("signal: {}{}", signal, name)
        } else {
            status.to_string()
        }
    }

    #[cfg(windows)]
    fn status_to_string(status: ExitStatus) -> String {
        use winapi::shared::minwindef::DWORD;
        use winapi::um::winnt::*;

        let mut base = status.to_string();
        let extra = match status.code().unwrap() as DWORD {
            STATUS_ACCESS_VIOLATION => "STATUS_ACCESS_VIOLATION",
            STATUS_IN_PAGE_ERROR => "STATUS_IN_PAGE_ERROR",
            STATUS_INVALID_HANDLE => "STATUS_INVALID_HANDLE",
            STATUS_INVALID_PARAMETER => "STATUS_INVALID_PARAMETER",
            STATUS_NO_MEMORY => "STATUS_NO_MEMORY",
            STATUS_ILLEGAL_INSTRUCTION => "STATUS_ILLEGAL_INSTRUCTION",
            STATUS_NONCONTINUABLE_EXCEPTION => "STATUS_NONCONTINUABLE_EXCEPTION",
            STATUS_INVALID_DISPOSITION => "STATUS_INVALID_DISPOSITION",
            STATUS_ARRAY_BOUNDS_EXCEEDED => "STATUS_ARRAY_BOUNDS_EXCEEDED",
            STATUS_FLOAT_DENORMAL_OPERAND => "STATUS_FLOAT_DENORMAL_OPERAND",
            STATUS_FLOAT_DIVIDE_BY_ZERO => "STATUS_FLOAT_DIVIDE_BY_ZERO",
            STATUS_FLOAT_INEXACT_RESULT => "STATUS_FLOAT_INEXACT_RESULT",
            STATUS_FLOAT_INVALID_OPERATION => "STATUS_FLOAT_INVALID_OPERATION",
            STATUS_FLOAT_OVERFLOW => "STATUS_FLOAT_OVERFLOW",
            STATUS_FLOAT_STACK_CHECK => "STATUS_FLOAT_STACK_CHECK",
            STATUS_FLOAT_UNDERFLOW => "STATUS_FLOAT_UNDERFLOW",
            STATUS_INTEGER_DIVIDE_BY_ZERO => "STATUS_INTEGER_DIVIDE_BY_ZERO",
            STATUS_INTEGER_OVERFLOW => "STATUS_INTEGER_OVERFLOW",
            STATUS_PRIVILEGED_INSTRUCTION => "STATUS_PRIVILEGED_INSTRUCTION",
            STATUS_STACK_OVERFLOW => "STATUS_STACK_OVERFLOW",
            STATUS_DLL_NOT_FOUND => "STATUS_DLL_NOT_FOUND",
            STATUS_ORDINAL_NOT_FOUND => "STATUS_ORDINAL_NOT_FOUND",
            STATUS_ENTRYPOINT_NOT_FOUND => "STATUS_ENTRYPOINT_NOT_FOUND",
            STATUS_CONTROL_C_EXIT => "STATUS_CONTROL_C_EXIT",
            STATUS_DLL_INIT_FAILED => "STATUS_DLL_INIT_FAILED",
            STATUS_FLOAT_MULTIPLE_FAULTS => "STATUS_FLOAT_MULTIPLE_FAULTS",
            STATUS_FLOAT_MULTIPLE_TRAPS => "STATUS_FLOAT_MULTIPLE_TRAPS",
            STATUS_REG_NAT_CONSUMPTION => "STATUS_REG_NAT_CONSUMPTION",
            STATUS_HEAP_CORRUPTION => "STATUS_HEAP_CORRUPTION",
            STATUS_STACK_BUFFER_OVERRUN => "STATUS_STACK_BUFFER_OVERRUN",
            STATUS_ASSERTION_FAILURE => "STATUS_ASSERTION_FAILURE",
            _ => return base,
        };
        base.push_str(", ");
        base.push_str(extra);
        base
    }
}

pub fn is_simple_exit_code(code: i32) -> bool {
    // Typical unix exit codes are 0 to 127.
    // Windows doesn't have anything "typical", and is a
    // 32-bit number (which appears signed here, but is really
    // unsigned). However, most of the interesting NTSTATUS
    // codes are very large. This is just a rough
    // approximation of which codes are "normal" and which
    // ones are abnormal termination.
    code >= 0 && code <= 127
}

pub fn internal<S: fmt::Display>(error: S) -> failure::Error {
    _internal(&error)
}

fn _internal(error: &dyn fmt::Display) -> failure::Error {
    Internal::new(failure::format_err!("{}", error)).into()
}

pub fn display_causes(error: &Error) -> String {
    error
        .iter_chain()
        .map(|e| e.to_string())
        .collect::<Vec<_>>()
        .join("\n\nCaused by:\n  ")
}