use std::process::Command;
use std::process::Output;

use ansi_term::Color;

use super::{Context, Module};

use crate::modules::utils::java_version_parser;

/// Creates a module with the current Java version
///
/// Will display the Java version if any of the following criteria are met:
///     - Current directory contains a file with a `.java`, `.class` or `.jar` extension
///     - Current directory contains a `pom.xml`, `build.gradle` or `build.sbt` file
pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
    let is_java_project = context
        .try_begin_scan()?
        .set_files(&["pom.xml", "build.gradle", "build.sbt"])
        .set_extensions(&["java", "class", "jar"])
        .is_match();

    if !is_java_project {
        return None;
    }

    match get_java_version() {
        Some(java_version) => {
            const JAVA_CHAR: &str = "☕ ";

            let mut module = context.new_module("java");
            let module_style = module
                .config_value_style("style")
                .unwrap_or_else(|| Color::Red.dimmed());
            module.set_style(module_style);

            let formatted_version = format_java_version(java_version)?;
            module.new_segment("symbol", JAVA_CHAR);
            module.new_segment("version", &formatted_version);

            Some(module)
        }
        None => None,
    }
}

fn get_java_version() -> Option<String> {
    let java_command = match std::env::var("JAVA_HOME") {
        Ok(java_home) => format!("{}/bin/java", java_home),
        Err(_) => String::from("java"),
    };

    match Command::new(java_command).arg("-Xinternalversion").output() {
        Ok(output) => Some(combine_outputs(output)),
        Err(_) => None,
    }
}

/// Combines the standard and error outputs.
///
/// This is due some Java vendors using `STDERR` as the output.
fn combine_outputs(output: Output) -> String {
    let std_out = String::from_utf8(output.stdout).unwrap();
    let std_err = String::from_utf8(output.stderr).unwrap();

    format!("{}{}", std_out, std_err)
}

/// Extract the java version from `java_out`.
fn format_java_version(java_out: String) -> Option<String> {
    java_version_parser::parse_jre_version(&java_out).map(|result| format!("v{}", result))
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_format_java_version_openjdk() {
        let java_8 = String::from("OpenJDK 64-Bit Server VM (25.222-b10) for linux-amd64 JRE (1.8.0_222-b10), built on Jul 11 2019 10:18:43 by \"openjdk\" with gcc 4.4.7 20120313 (Red Hat 4.4.7-23)");
        let java_11 = String::from("OpenJDK 64-Bit Server VM (11.0.4+11-post-Ubuntu-1ubuntu219.04) for linux-amd64 JRE (11.0.4+11-post-Ubuntu-1ubuntu219.04), built on Jul 18 2019 18:21:46 by \"build\" with gcc 8.3.0");
        assert_eq!(format_java_version(java_11), Some(String::from("v11.0.4")));
        assert_eq!(format_java_version(java_8), Some(String::from("v1.8.0")));
    }

    #[test]
    fn test_format_java_version_oracle() {
        let java_8 = String::from("Java HotSpot(TM) Client VM (25.65-b01) for linux-arm-vfp-hflt JRE (1.8.0_65-b17), built on Oct  6 2015 16:19:04 by \"java_re\" with gcc 4.7.2 20120910 (prerelease)");
        assert_eq!(format_java_version(java_8), Some(String::from("v1.8.0")));
    }

    #[test]
    fn test_format_java_version_redhat() {
        let java_8 = String::from("OpenJDK 64-Bit Server VM (25.222-b10) for linux-amd64 JRE (1.8.0_222-b10), built on Jul 11 2019 20:48:53 by \"root\" with gcc 7.3.1 20180303 (Red Hat 7.3.1-5)");
        let java_12 = String::from("OpenJDK 64-Bit Server VM (12.0.2+10) for linux-amd64 JRE (12.0.2+10), built on Jul 18 2019 14:41:47 by \"jenkins\" with gcc 7.3.1 20180303 (Red Hat 7.3.1-5)");
        assert_eq!(format_java_version(java_8), Some(String::from("v1.8.0")));
        assert_eq!(format_java_version(java_12), Some(String::from("v12.0.2")));
    }

    #[test]
    fn test_format_java_version_zulu() {
        let java_8 = String::from("OpenJDK 64-Bit Server VM (25.222-b10) for linux-amd64 JRE (Zulu 8.40.0.25-CA-linux64) (1.8.0_222-b10), built on Jul 11 2019 11:36:39 by \"zulu_re\" with gcc 4.4.7 20120313 (Red Hat 4.4.7-3)");
        let java_11 = String::from("OpenJDK 64-Bit Server VM (11.0.4+11-LTS) for linux-amd64 JRE (Zulu11.33+15-CA) (11.0.4+11-LTS), built on Jul 11 2019 21:37:17 by \"zulu_re\" with gcc 4.9.2 20150212 (Red Hat 4.9.2-6)");
        assert_eq!(format_java_version(java_8), Some(String::from("v1.8.0")));
        assert_eq!(format_java_version(java_11), Some(String::from("v11.0.4")));
    }

    #[test]
    fn test_format_java_version_eclipse_openj9() {
        let java_8 = String::from("Eclipse OpenJ9 OpenJDK 64-bit Server VM (1.8.0_222-b10) from linux-amd64 JRE with Extensions for OpenJDK for Eclipse OpenJ9 8.0.222.0, built on Jul 17 2019 21:29:18 by jenkins with g++ (GCC) 7.3.1 20180303 (Red Hat 7.3.1-5)");
        let java_11 = String::from("Eclipse OpenJ9 OpenJDK 64-bit Server VM (11.0.4+11) from linux-amd64 JRE with Extensions for OpenJDK for Eclipse OpenJ9 11.0.4.0, built on Jul 17 2019 21:51:37 by jenkins with g++ (GCC) 7.3.1 20180303 (Red Hat 7.3.1-5)");
        assert_eq!(format_java_version(java_8), Some(String::from("v1.8.0")));
        assert_eq!(format_java_version(java_11), Some(String::from("v11.0.4")));
    }

    #[test]
    fn test_format_java_version_graalvm() {
        let java_8 = String::from("OpenJDK 64-Bit GraalVM CE 19.2.0.1 (25.222-b08-jvmci-19.2-b02) for linux-amd64 JRE (8u222), built on Jul 19 2019 17:37:13 by \"buildslave\" with gcc 7.3.0");
        assert_eq!(format_java_version(java_8), Some(String::from("v8")));
    }

    #[test]
    fn test_format_java_version_amazon_corretto() {
        let java_8 = String::from("OpenJDK 64-Bit Server VM (25.222-b10) for linux-amd64 JRE (1.8.0_222-b10), built on Jul 11 2019 20:48:53 by \"root\" with gcc 7.3.1 20180303 (Red Hat 7.3.1-5)");
        let java_11 = String::from("OpenJDK 64-Bit Server VM (11.0.4+11-LTS) for linux-amd64 JRE (11.0.4+11-LTS), built on Jul 11 2019 20:06:11 by \"\" with gcc 7.3.1 20180303 (Red Hat 7.3.1-5)");
        assert_eq!(format_java_version(java_8), Some(String::from("v1.8.0")));
        assert_eq!(format_java_version(java_11), Some(String::from("v11.0.4")));
    }

    #[test]
    fn test_format_java_version_sapmachine() {
        let java_11 = String::from("OpenJDK 64-Bit Server VM (11.0.4+11-LTS-sapmachine) for linux-amd64 JRE (11.0.4+11-LTS-sapmachine), built on Jul 17 2019 08:58:43 by \"\" with gcc 7.3.0");
        assert_eq!(format_java_version(java_11), Some(String::from("v11.0.4")));
    }

    #[test]
    fn test_format_java_version_unknown() {
        let unknown_jre = String::from("Unknown JRE");
        assert_eq!(format_java_version(unknown_jre), None);
    }
}