use std::{path::Path, sync::LazyLock};

fn build_from_executable(executable: &Path) -> Option<String> {
    let macos = executable.parent()?;
    let contents = macos.parent()?;
    if macos.file_name()? != "MacOS" || contents.file_name()? != "Contents" {
        return None;
    }
    let output = std::process::Command::new("/usr/bin/plutil")
        .args(["-extract", "CFBundleVersion", "raw", "-o", "-"])
        .arg(contents.join("Info.plist"))
        .output()
        .ok()?;
    if !output.status.success() {
        return Some("unknown".into());
    }
    let build = String::from_utf8(output.stdout).ok()?;
    Some(build.trim().to_owned())
}

pub fn build_number() -> &'static str {
    static BUILD: LazyLock<String> = LazyLock::new(|| {
        std::env::current_exe()
            .ok()
            .and_then(|executable| build_from_executable(&executable))
            .unwrap_or_else(|| {
                // Tauri omits macOS bundle settings from its generated runtime config.
                let config: serde_json::Value =
                    serde_json::from_str(include_str!("../tauri.conf.json")).unwrap();
                config["bundle"]["macOS"]["bundleVersion"]
                    .as_str()
                    .unwrap_or("unknown")
                    .to_owned()
            })
    });
    &BUILD
}

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

    #[test]
    fn installed_build_comes_from_the_app_plist_instead_of_the_app_version() {
        let root = std::env::temp_dir().join(format!("kanbangit-build-{}", std::process::id()));
        let contents = root.join("KanbanGit.app/Contents");
        std::fs::create_dir_all(contents.join("MacOS")).unwrap();
        let executable = contents.join("MacOS/kanbangit-native");
        std::fs::write(contents.join("Info.plist"), r#"<?xml version="1.0" encoding="UTF-8"?><plist version="1.0"><dict><key>CFBundleShortVersionString</key><string>0.1.3</string><key>CFBundleVersion</key><string>42</string></dict></plist>"#).unwrap();
        assert_eq!(build_from_executable(&executable).as_deref(), Some("42"));
        std::fs::remove_file(contents.join("Info.plist")).unwrap();
        assert_eq!(
            build_from_executable(&executable).as_deref(),
            Some("unknown")
        );
        std::fs::remove_dir_all(root).unwrap();
    }

    #[test]
    fn unbundled_execution_uses_the_configured_build() {
        assert!(build_from_executable(Path::new("/tmp/target/debug/kanbangit-native")).is_none());
        let config: serde_json::Value =
            serde_json::from_str(include_str!("../tauri.conf.json")).unwrap();
        assert_eq!(
            build_number(),
            config["bundle"]["macOS"]["bundleVersion"].as_str().unwrap()
        );
    }
}