//! A couple of functions to enable and disable coloring.

use std::default::Default;
use std::env;
use std::sync::atomic::{AtomicBool, Ordering};
#[cfg(windows)]
use winconsole::{console, errors::WinResult};

/// Sets a flag to the console to use a virtual terminal environment.
/// This is primarily used for Windows 10 environments which will not correctly colorize the outputs based on ansi escape codes.
///
/// # Notes
/// > Only available to `Windows` build targets.
///
/// # Example
/// ```rust
/// use colored::*;
/// control::set_virtual_terminal(false);
/// println!("{}", "bright cyan".bright_cyan());	// will print 'bright cyan' on windows 10
///
/// control::set_virtual_terminal(true);
/// println!("{}", "bright cyan".bright_cyan());	// will print correctly
/// ```
#[cfg(windows)]
pub fn set_virtual_terminal(use_virtual: bool) -> WinResult<()> {
	let mut mode = console::get_output_mode()?;
	mode.VirtualTerminalProcessing = use_virtual;
	console::set_output_mode(mode)?;
	Ok(())
}

pub struct ShouldColorize {
    clicolor: Option<bool>,
    clicolor_force: Option<bool>,
    // XXX we can't use Option<Atomic> because we can't use &mut references to ShouldColorize
    has_manual_override: AtomicBool,
    manual_override: AtomicBool,
}

/// Use this to force colored to ignore the environment and always/never colorize
/// See example/control.rs
pub fn set_override(override_colorize: bool) {
    SHOULD_COLORIZE.set_override(override_colorize)
}

/// Remove the manual override and let the environment decide if it's ok to colorize
/// See example/control.rs
pub fn unset_override() {
    SHOULD_COLORIZE.unset_override()
}

lazy_static! {
    pub static ref SHOULD_COLORIZE: ShouldColorize = ShouldColorize::from_env();
}

impl Default for ShouldColorize {
    fn default() -> ShouldColorize {
        ShouldColorize {
            clicolor: None,
            clicolor_force: None,
            has_manual_override: AtomicBool::new(false),
            manual_override: AtomicBool::new(false),
        }
    }
}

impl ShouldColorize {
    /// Reads environment variables to determine whether colorization should
    /// be used or not. `CLICOLOR_FORCE` takes highest priority, followed by
    /// `NO_COLOR`, followed by `CLICOLOR`. In the absence of manual overrides,
    /// which take precedence over all environment variables, the priority
    /// of these variables can be expressed as follows.
    ///
    /// `NO_COLOR`  | `CLICOLOR`          | `CLICOLOR_FORCE`   | colorize?
    /// :---------  | :---------          | :---------------   | :--------
    /// unset       | unset               | unset              | true (default)
    /// unset       | `!= 0`              | unset              | true
    /// unset       | `== 0`              | unset              | false
    /// set         | unset/`== 0`/`!= 0` | unset              | false
    /// set/unset   | unset/`== 0`/`!= 0` | `== 0`             | false
    /// set/unset   | unset/`== 0`/`!= 0` | `!= 0`             | true
    pub fn from_env() -> Self {
        use std::io;

        ShouldColorize {
            clicolor: ShouldColorize::normalize_env(env::var("CLICOLOR")),
            clicolor_force: ShouldColorize::resolve_clicolor_force(
                env::var("NO_COLOR"),
                env::var("CLICOLOR_FORCE"),
            ),
            ..ShouldColorize::default()
        }
    }

    pub fn should_colorize(&self) -> bool {
        if self.has_manual_override.load(Ordering::Relaxed) {
            return self.manual_override.load(Ordering::Relaxed);
        }

        if let Some(forced_value) = self.clicolor_force {
            return forced_value;
        }

        if let Some(value) = self.clicolor {
            return value;
        }

        true
    }

    pub fn set_override(&self, override_colorize: bool) {
        self.has_manual_override.store(true, Ordering::Relaxed);
        self.manual_override
            .store(override_colorize, Ordering::Relaxed);
    }

    pub fn unset_override(&self) {
        self.has_manual_override.store(false, Ordering::Relaxed);
    }

    /* private */

    fn normalize_env(env_res: Result<String, env::VarError>) -> Option<bool> {
        match env_res {
            Ok(string) => Some(string != "0"),
            Err(_) => None,
        }
    }

    fn resolve_clicolor_force(
        no_color: Result<String, env::VarError>,
        clicolor_force: Result<String, env::VarError>,
    ) -> Option<bool> {
        match (
            ShouldColorize::normalize_env(no_color),
            ShouldColorize::normalize_env(clicolor_force),
        ) {
            (_, Some(b)) => Some(b),
            (Some(_), None) => Some(false),
            (None, None) => None,
        }
    }
}

#[cfg(test)]
mod specs {
    use super::*;
    use rspec;
    use rspec::context::*;
    use std::env;

    #[test]
    fn clicolor_behavior() {
        use std::io;

        let stdout = &mut io::stdout();
        let mut formatter = rspec::formatter::Simple::new(stdout);
        let mut runner = describe("ShouldColorize", |ctx| {
            ctx.describe("::normalize_env", |ctx| {
                ctx.it("should return None if error", || {
                    assert_eq!(
                        None,
                        ShouldColorize::normalize_env(Err(env::VarError::NotPresent))
                    );
                    assert_eq!(
                        None,
                        ShouldColorize::normalize_env(Err(env::VarError::NotUnicode("".into())))
                    )
                });

                ctx.it("should return Some(true) if != 0", || {
                    Some(true) == ShouldColorize::normalize_env(Ok(String::from("1")))
                });

                ctx.it("should return Some(false) if == 0", || {
                    Some(false) == ShouldColorize::normalize_env(Ok(String::from("0")))
                });
            });

            ctx.describe("::resolve_clicolor_force", |ctx| {
                ctx.it(
                    "should return None if neither NO_COLOR nor CLICOLOR_FORCE are set",
                    || {
                        assert_eq!(
                            None,
                            ShouldColorize::resolve_clicolor_force(
                                Err(env::VarError::NotPresent),
                                Err(env::VarError::NotPresent)
                            )
                        );
                    },
                );

                ctx.it(
                    "should return Some(false) if NO_COLOR is set and CLICOLOR_FORCE is unset",
                    || {
                        assert_eq!(
                            Some(false),
                            ShouldColorize::resolve_clicolor_force(
                                Ok(String::from("0")),
                                Err(env::VarError::NotPresent)
                            )
                        );
                        assert_eq!(
                            Some(false),
                            ShouldColorize::resolve_clicolor_force(
                                Ok(String::from("1")),
                                Err(env::VarError::NotPresent)
                            )
                        );
                    },
                );

                ctx.it(
                    "should ignore NO_COLOR and return Some(forced_value) if CLICOLOR_FORCE is set to forced_value",
                    || {
                        assert_eq!(
                            Some(true),
                            ShouldColorize::resolve_clicolor_force(
                                Ok(String::from("1")),
                                Ok(String::from("1")),
                            )
                        );
                        assert_eq!(
                            Some(false),
                            ShouldColorize::resolve_clicolor_force(
                                Ok(String::from("1")),
                                Ok(String::from("0")),
                            )
                        );
                        assert_eq!(
                            Some(false),
                            ShouldColorize::resolve_clicolor_force(
                                Err(env::VarError::NotPresent),
                                Ok(String::from("0")),
                            )
                        );
                        assert_eq!(
                            Some(true),
                            ShouldColorize::resolve_clicolor_force(
                                Err(env::VarError::NotPresent),
                                Ok(String::from("1")),
                            )
                        );
                    },
                );
            });

            ctx.describe("constructors", |ctx| {
                ctx.it("should have a default constructor", || {
                    ShouldColorize::default();
                });

                ctx.it("should have an environment constructor", || {
                    ShouldColorize::from_env();
                });
            });

            ctx.describe("when only changing clicolors", |ctx| {
                ctx.it("clicolor == false means no colors", || {
                    let colorize_control = ShouldColorize {
                        clicolor: Some(false),
                        ..ShouldColorize::default()
                    };
                    false == colorize_control.should_colorize()
                });

                ctx.it("clicolor == true means colors !", || {
                    let colorize_control = ShouldColorize {
                        clicolor: Some(true),
                        ..ShouldColorize::default()
                    };
                    true == colorize_control.should_colorize()
                });

                ctx.it("unset clicolors implies true", || {
                    true == ShouldColorize::default().should_colorize()
                });
            });

            ctx.describe("when using clicolor_force", |ctx| {
                ctx.it(
                    "clicolor_force should force to true no matter clicolor",
                    || {
                        let colorize_control = ShouldColorize {
                            clicolor: Some(false),
                            clicolor_force: Some(true),
                            ..ShouldColorize::default()
                        };

                        true == colorize_control.should_colorize()
                    },
                );

                ctx.it(
                    "clicolor_force should force to false no matter clicolor",
                    || {
                        let colorize_control = ShouldColorize {
                            clicolor: Some(true),
                            clicolor_force: Some(false),
                            ..ShouldColorize::default()
                        };

                        false == colorize_control.should_colorize()
                    },
                );
            });

            ctx.describe("using a manual override", |ctx| {
                ctx.it("shoud colorize if manual_override is true, but clicolor is false and clicolor_force also false", || {
                    let colorize_control = ShouldColorize {
                        clicolor: Some(false),
                        clicolor_force: None,
                        has_manual_override: AtomicBool::new(true),
                        manual_override: AtomicBool::new(true),
                        .. ShouldColorize::default()
                    };

                    true == colorize_control.should_colorize()
                });

                ctx.it("should not colorize if manual_override is false, but clicolor is true or clicolor_force is true", || {
                    let colorize_control = ShouldColorize {
                        clicolor: Some(true),
                        clicolor_force: Some(true),
                        has_manual_override: AtomicBool::new(true),
                        manual_override: AtomicBool::new(false),
                        .. ShouldColorize::default()
                    };

                    false == colorize_control.should_colorize()
                })
            });

            ctx.describe("::set_override", |ctx| {
                ctx.it("should exists", || {
                    let colorize_control = ShouldColorize::default();
                    colorize_control.set_override(true);
                });

                ctx.it("set the manual_override property", || {
                    let colorize_control = ShouldColorize::default();
                    colorize_control.set_override(true);
                    {
                        assert_eq!(
                            true,
                            colorize_control.has_manual_override.load(Ordering::Relaxed)
                        );
                        let val = colorize_control.manual_override.load(Ordering::Relaxed);
                        assert_eq!(true, val);
                    }
                    colorize_control.set_override(false);
                    {
                        assert_eq!(
                            true,
                            colorize_control.has_manual_override.load(Ordering::Relaxed)
                        );
                        let val = colorize_control.manual_override.load(Ordering::Relaxed);
                        assert_eq!(false, val);
                    }
                });
            });

            ctx.describe("::unset_override", |ctx| {
                ctx.it("should exists", || {
                    let colorize_control = ShouldColorize::default();
                    colorize_control.unset_override();
                });

                ctx.it("unset the manual_override property", || {
                    let colorize_control = ShouldColorize::default();
                    colorize_control.set_override(true);
                    colorize_control.unset_override();
                    assert_eq!(
                        false,
                        colorize_control.has_manual_override.load(Ordering::Relaxed)
                    );
                });
            });
        });
        runner.add_event_handler(&mut formatter);
        runner.run().unwrap();
    }
}