#[cfg(windows)]
use std::os::windows::process::CommandExt;
use std::process::ExitStatus;

use crate::benchmark::measurement::Measurement;
use crate::benchmark::measurement::Measurements;
use crate::command::Command;
use crate::options::{
    CmdFailureAction, CommandInputPolicy, CommandOutputPolicy, Options, OutputStyleOption, Shell,
};
use crate::output::progress_bar::get_progress_bar;
use crate::quantity::{second, Information, Time, Zero};
use crate::timer::execute_and_measure;
use crate::util::randomized_environment_offset;

use anyhow::{bail, Context, Result};

#[derive(Clone, Copy)]
pub enum BenchmarkIteration {
    NonBenchmarkRun,
    Warmup(u64),
    Benchmark(u64),
}

impl BenchmarkIteration {
    pub fn to_env_var_value(&self) -> Option<String> {
        match self {
            BenchmarkIteration::NonBenchmarkRun => None,
            BenchmarkIteration::Warmup(i) => Some(format!("warmup-{}", i)),
            BenchmarkIteration::Benchmark(i) => Some(format!("{}", i)),
        }
    }
}

pub trait Executor {
    /// Run the given command and measure the execution time
    fn run_command_and_measure(
        &self,
        command: &Command<'_>,
        iteration: BenchmarkIteration,
        command_failure_action: Option<CmdFailureAction>,
        output_policy: &CommandOutputPolicy,
    ) -> Result<Measurement>;

    /// Perform a calibration of this executor. For example,
    /// when running commands through a shell, we need to
    /// measure the shell spawning time separately in order
    /// to subtract it from the full runtime later.
    fn calibrate(&mut self) -> Result<()>;

    /// Return the time overhead for this executor when
    /// performing a measurement. This should return the time
    /// that is being used in addition to the actual runtime
    /// of the command.
    fn time_overhead(&self) -> Time;
}

fn run_command_and_measure_common(
    mut command: std::process::Command,
    iteration: BenchmarkIteration,
    command_failure_action: CmdFailureAction,
    command_input_policy: &CommandInputPolicy,
    command_output_policy: &CommandOutputPolicy,
    command_name: &str,
    collect_hardware_counters: bool,
) -> Result<Measurement> {
    let stdin = command_input_policy.get_stdin()?;
    let (stdout, stderr) = command_output_policy.get_stdout_stderr()?;
    command.stdin(stdin).stdout(stdout).stderr(stderr);

    command.env(
        "HYPERFINE_RANDOMIZED_ENVIRONMENT_OFFSET",
        randomized_environment_offset::value(),
    );

    if let Some(value) = iteration.to_env_var_value() {
        command.env("HYPERFINE_ITERATION", value);
    }

    let measurement = execute_and_measure(command, collect_hardware_counters)
        .with_context(|| format!("Failed to run command '{command_name}'"))?;

    if !measurement.exit_status.success() {
        use crate::util::exit_code::extract_exit_code;

        let should_fail = match command_failure_action {
            CmdFailureAction::RaiseError => true,
            CmdFailureAction::IgnoreAllFailures => false,
            CmdFailureAction::IgnoreSpecificFailures(ref codes) => {
                // Only fail if the exit code is not in the list of codes to ignore
                if let Some(exit_code) = extract_exit_code(measurement.exit_status) {
                    !codes.contains(&exit_code)
                } else {
                    // If we can't extract an exit code, treat it as a failure
                    true
                }
            }
        };

        if should_fail {
            let when = match iteration {
                BenchmarkIteration::NonBenchmarkRun => "a non-benchmark run".to_string(),
                BenchmarkIteration::Warmup(0) => "the first warmup run".to_string(),
                BenchmarkIteration::Warmup(i) => format!("warmup iteration {i}"),
                BenchmarkIteration::Benchmark(0) => "the first benchmark run".to_string(),
                BenchmarkIteration::Benchmark(i) => format!("benchmark iteration {i}"),
            };
            bail!(
                "{cause} in {when}. Use the '-i'/'--ignore-failure' option if you want to ignore this. \
                Alternatively, use the '--show-output' option to debug what went wrong.",
                cause=measurement.exit_status.code().map_or(
                    "The process has been terminated by a signal".into(),
                    |c| format!("Command terminated with non-zero exit code {c}")

                ),
            );
        }
    }

    Ok(measurement)
}

pub struct RawExecutor<'a> {
    options: &'a Options,
}

impl<'a> RawExecutor<'a> {
    pub fn new(options: &'a Options) -> Self {
        RawExecutor { options }
    }
}

impl Executor for RawExecutor<'_> {
    fn run_command_and_measure(
        &self,
        command: &Command<'_>,
        iteration: BenchmarkIteration,
        command_failure_action: Option<CmdFailureAction>,
        output_policy: &CommandOutputPolicy,
    ) -> Result<Measurement> {
        run_command_and_measure_common(
            command.get_command()?,
            iteration,
            command_failure_action.unwrap_or_else(|| self.options.command_failure_action.clone()),
            &self.options.command_input_policy,
            output_policy,
            &command.get_command_line(),
            matches!(iteration, BenchmarkIteration::Benchmark(_)),
        )
    }

    fn calibrate(&mut self) -> Result<()> {
        Ok(())
    }

    fn time_overhead(&self) -> Time {
        Time::zero()
    }
}

pub struct ShellExecutor<'a> {
    options: &'a Options,
    shell: &'a Shell,
    shell_spawning_time: Option<Measurement>,
}

impl<'a> ShellExecutor<'a> {
    pub fn new(shell: &'a Shell, options: &'a Options) -> Self {
        ShellExecutor {
            shell,
            options,
            shell_spawning_time: None,
        }
    }
}

impl Executor for ShellExecutor<'_> {
    fn run_command_and_measure(
        &self,
        command: &Command<'_>,
        iteration: BenchmarkIteration,
        command_failure_action: Option<CmdFailureAction>,
        output_policy: &CommandOutputPolicy,
    ) -> Result<Measurement> {
        let on_windows_cmd = cfg!(windows) && *self.shell == Shell::Default("cmd.exe");
        let mut command_builder = self.shell.command();
        command_builder.arg(if on_windows_cmd { "/C" } else { "-c" });

        // Windows needs special treatment for its behavior on parsing cmd arguments
        if on_windows_cmd {
            #[cfg(windows)]
            command_builder.raw_arg(command.get_command_line());
        } else {
            command_builder.arg(command.get_command_line());
        }

        let mut measurement = run_command_and_measure_common(
            command_builder,
            iteration,
            command_failure_action.unwrap_or_else(|| self.options.command_failure_action.clone()),
            &self.options.command_input_policy,
            output_policy,
            &command.get_command_line(),
            false,
        )?;

        // Subtract shell spawning time
        fn ensure_non_negative(time: Time) -> Time {
            if time < Time::zero() {
                Time::zero()
            } else {
                time
            }
        }

        if let Some(ref spawning_time) = self.shell_spawning_time {
            measurement.time_wall_clock =
                ensure_non_negative(measurement.time_wall_clock - spawning_time.time_wall_clock);
            measurement.time_user =
                ensure_non_negative(measurement.time_user - spawning_time.time_user);
            measurement.time_system =
                ensure_non_negative(measurement.time_system - spawning_time.time_system);
            measurement.time_cpu = measurement.time_user + measurement.time_system;
        }

        Ok(measurement)
    }

    /// Measure the average shell spawning time
    fn calibrate(&mut self) -> Result<()> {
        const COUNT: u64 = 50;
        let progress_bar = if self.options.output_style != OutputStyleOption::Disabled {
            Some(get_progress_bar(
                COUNT,
                "Measuring shell spawning time",
                self.options.output_style,
            ))
        } else {
            None
        };

        let mut measurements = Measurements::default();

        for _ in 0..COUNT {
            // Just run the shell without any command
            let measurement = self.run_command_and_measure(
                &Command::new(None, ""),
                BenchmarkIteration::NonBenchmarkRun,
                None,
                &CommandOutputPolicy::Null,
            );

            match measurement {
                Err(_) => {
                    let shell_cmd = if cfg!(windows) {
                        format!("{} /C \"\"", self.shell)
                    } else {
                        format!("{} -c \"\"", self.shell)
                    };

                    bail!(
                        "Could not measure shell execution time. Make sure you can run '{}'.",
                        shell_cmd
                    );
                }
                Ok(result) => {
                    measurements.push(result);
                }
            }

            if let Some(bar) = progress_bar.as_ref() {
                bar.inc(1)
            }
        }

        if let Some(bar) = progress_bar.as_ref() {
            bar.finish_and_clear()
        }

        self.shell_spawning_time = Some(Measurement {
            time_wall_clock: measurements.time_wall_clock_mean(),
            time_cpu: measurements.time_user_mean() + measurements.time_system_mean(),
            time_user: measurements.time_user_mean(),
            time_system: measurements.time_system_mean(),
            memory_peak_resident: None,
            hardware_counters: Default::default(),
            exit_status: ExitStatus::default(),
        });

        Ok(())
    }

    fn time_overhead(&self) -> Time {
        self.shell_spawning_time.as_ref().unwrap().time_wall_clock
    }
}

#[derive(Clone)]
pub struct MockExecutor {
    shell: Option<String>,
}

impl MockExecutor {
    pub fn new(shell: Option<String>) -> Self {
        MockExecutor { shell }
    }

    fn extract_time<S: AsRef<str>>(sleep_command: S) -> Time {
        assert!(sleep_command.as_ref().starts_with("sleep "));
        Time::new::<second>(
            sleep_command
                .as_ref()
                .trim_start_matches("sleep ")
                .parse::<f64>()
                .unwrap(),
        )
    }
}

impl Executor for MockExecutor {
    fn run_command_and_measure(
        &self,
        command: &Command<'_>,
        _iteration: BenchmarkIteration,
        _command_failure_action: Option<CmdFailureAction>,
        _output_policy: &CommandOutputPolicy,
    ) -> Result<Measurement> {
        #[cfg(unix)]
        let exit_status = {
            use std::os::unix::process::ExitStatusExt;
            ExitStatus::from_raw(0)
        };

        #[cfg(windows)]
        let exit_status = {
            use std::os::windows::process::ExitStatusExt;
            ExitStatus::from_raw(0)
        };

        Ok(Measurement {
            time_wall_clock: Self::extract_time(command.get_command_line()),
            time_cpu: Time::zero(),
            time_user: Time::zero(),
            time_system: Time::zero(),
            memory_peak_resident: Some(Information::zero()),
            hardware_counters: Default::default(),
            exit_status,
        })
    }

    fn calibrate(&mut self) -> Result<()> {
        Ok(())
    }

    fn time_overhead(&self) -> Time {
        match &self.shell {
            None => Time::zero(),
            Some(shell) => Self::extract_time(shell),
        }
    }
}

#[test]
fn test_mock_executor_extract_time() {
    assert_eq!(
        MockExecutor::extract_time("sleep 0.1"),
        Time::new::<second>(0.1)
    );
}