//! Low level terminal capability lookups

#![cfg_attr(docsrs, feature(doc_cfg))]

#![warn(missing_docs)]

#![warn(clippy::print_stderr)]

#![warn(clippy::print_stdout)]

pub mod windows;

/// Check [CLICOLOR] status

///

/// - When `true`, ANSI colors are supported and should be used when the program isn't piped,

///   similar to [`term_supports_color`]

/// - When `false`, don’t output ANSI color escape codes, similar to [`no_color`]

///

/// See also:

/// - [terminfo](https://crates.io/crates/terminfo) or [term](https://crates.io/crates/term) for

///   checking termcaps

/// - [termbg](https://crates.io/crates/termbg) for detecting background color

///

/// [CLICOLOR]: https://bixense.com/clicolors/

#[inline]

pub fn clicolor() -> Option<bool> {

    let value = std::env::var_os("CLICOLOR")?;

    Some(value != "0")

}

/// Check [CLICOLOR_FORCE] status

///

/// ANSI colors should be enabled no matter what.

///

/// [CLICOLOR_FORCE]: https://bixense.com/clicolors/

#[inline]

pub fn clicolor_force() -> bool {

    non_empty(std::env::var_os("CLICOLOR_FORCE").as_deref())

}

/// Check [NO_COLOR] status

///

/// When `true`, should prevent the addition of ANSI color.

///

/// User-level configuration files and per-instance command-line arguments should override

/// [NO_COLOR]. A user should be able to export `$NO_COLOR` in their shell configuration file as a

/// default, but configure a specific program in its configuration file to specifically enable

/// color.

///

/// [NO_COLOR]: https://no-color.org/

#[inline]

pub fn no_color() -> bool {

    non_empty(std::env::var_os("NO_COLOR").as_deref())

}

/// Check `TERM` for color support

#[inline]

pub fn term_supports_color() -> bool {

    #[cfg(not(windows))]

    {

        match std::env::var_os("TERM") {

            // If TERM isn't set, then we are in a weird environment that

            // probably doesn't support colors.

            None => return false,

            Some(k) => {

                if k == "dumb" {

                    return false;

                }

            }

        }

        true

    }

    #[cfg(windows)]

    {

        // On Windows, if TERM isn't set, then we shouldn't automatically

        // assume that colors aren't allowed. This is unlike Unix environments

        // where TERM is more rigorously set.

        if let Some(k) = std::env::var_os("TERM") {

            if k == "dumb" {

                return false;

            }

        }

        true

    }

}

/// Check `TERM` for ANSI color support

///

/// On Windows, you might need to also check [`windows::enable_ansi_colors`] as ANSI color support

/// is opt-in, rather than assumed.

#[inline]

pub fn term_supports_ansi_color() -> bool {

    #[cfg(not(windows))]

    {

        term_supports_color()

    }

    #[cfg(windows)]

    {

        match std::env::var_os("TERM") {

            None => return false,

            Some(k) => {

                // cygwin doesn't seem to support ANSI escape sequences

                // and instead has its own variety. However, the Windows

                // console API may be available.

                if k == "dumb" || k == "cygwin" {

                    return false;

                }

            }

        }

        true

    }

}

/// Check [COLORTERM] for truecolor support

///

/// [COLORTERM]: https://github.com/termstandard/colors

#[inline]

pub fn truecolor() -> bool {

    let value = std::env::var_os("COLORTERM");

    let value = value.as_deref().unwrap_or_default();

    value == "truecolor" || value == "24bit"

}

/// Report whether this is running in CI

///

/// CI is a common environment where, despite being piped, ansi color codes are supported

///

/// This is not as exhaustive as you'd find in a crate like `is_ci` but it should work in enough

/// cases.

#[inline]

pub fn is_ci() -> bool {

    // Assuming its CI based on presence because who would be setting `CI=false`?

    //

    // This makes it easier to all of the potential values when considering our known values:

    // - Gitlab and Github set it to `true`

    // - Woodpecker sets it to `woodpecker`

    std::env::var_os("CI").is_some()

}

fn non_empty(var: Option<&std::ffi::OsStr>) -> bool {

    !var.unwrap_or_default().is_empty()

}

#[cfg(test)]

mod test {

    use super::*;

    #[test]

    fn non_empty_not_present() {

        assert!(!non_empty(None));

    }

    #[test]

    fn non_empty_empty() {

        assert!(!non_empty(Some(std::ffi::OsStr::new(""))));

    }

    #[test]

    fn non_empty_texty() {

        assert!(non_empty(Some(std::ffi::OsStr::new("hello"))));

    }

}

#[doc = include_str!("../README.md")]

#[cfg(doctest)]

pub struct ReadmeDoctests;