use super::{InstalledCache, PackageError, PackageManager};
use std::collections::HashSet;
use std::io::Write;
use std::process::{Command, Stdio};

/// APT package manager (Debian/Ubuntu).
pub struct Apt {
    dry_run: bool,
    use_sudo: bool,
    installed_cache: InstalledCache,
}

impl Apt {
    pub fn new() -> Self {
        Self {
            dry_run: false,
            use_sudo: true,
            installed_cache: InstalledCache::default(),
        }
    }

    /// Loads all installed package names in one `dpkg-query` call.
    fn load_installed() -> Result<HashSet<String>, PackageError> {
        let output = Command::new("dpkg-query")
            .args(["-W", "-f", "${Package}\n"])
            .output()?;
        let mut set = HashSet::new();
        if output.status.success() {
            for line in String::from_utf8_lossy(&output.stdout).lines() {
                let name = line.trim();
                if !name.is_empty() {
                    set.insert(name.to_lowercase());
                }
            }
        }
        Ok(set)
    }

    pub fn dry_run(mut self, dry_run: bool) -> Self {
        self.dry_run = dry_run;
        self
    }

    pub fn use_sudo(mut self, use_sudo: bool) -> Self {
        self.use_sudo = use_sudo;
        self
    }

    #[tracing::instrument(skip(self))]
    fn run_apt(&self, args: &[&str]) -> Result<(), PackageError> {
        if self.dry_run {
            let prefix = if self.use_sudo { "sudo " } else { "" };
            println!("[dry-run] {}apt {}", prefix, args.join(" "));
            return Ok(());
        }

        let output = if self.use_sudo {
            Command::new("sudo").arg("apt").args(args).output()?
        } else {
            Command::new("apt").args(args).output()?
        };

        if !output.status.success() {
            return Err(PackageError::InstallFailed {
                package: args.join(" "),
                message: String::from_utf8_lossy(&output.stderr).to_string(),
            });
        }

        Ok(())
    }

    #[tracing::instrument(skip(self, password))]
    fn run_apt_with_password(&self, args: &[&str], password: &str) -> Result<(), PackageError> {
        if self.dry_run {
            println!("[dry-run] sudo apt {}", args.join(" "));
            return Ok(());
        }

        let mut child = Command::new("sudo")
            .arg("-S")
            .arg("apt")
            .args(args)
            .stdin(Stdio::piped())
            .stdout(Stdio::piped())
            .stderr(Stdio::piped())
            .spawn()?;

        if let Some(mut stdin) = child.stdin.take() {
            writeln!(stdin, "{}", password).ok();
        }

        let output = child.wait_with_output()?;

        if !output.status.success() {
            return Err(PackageError::InstallFailed {
                package: args.join(" "),
                message: String::from_utf8_lossy(&output.stderr).to_string(),
            });
        }

        Ok(())
    }
}

impl PackageManager for Apt {
    fn name(&self) -> &'static str {
        "apt"
    }

    fn is_available(&self) -> bool {
        std::path::Path::new("/usr/bin/apt").exists()
    }

    fn needs_sudo(&self) -> bool {
        self.use_sudo
    }

    fn install(&self, packages: &[String]) -> Result<(), PackageError> {
        if packages.is_empty() {
            return Ok(());
        }

        let mut args = vec!["install", "-y"];
        for pkg in packages {
            args.push(pkg);
        }

        let result = self.run_apt(&args);
        self.installed_cache.invalidate();
        result
    }

    fn install_with_sudo(&self, packages: &[String], password: &str) -> Result<(), PackageError> {
        if packages.is_empty() {
            return Ok(());
        }

        let mut args = vec!["install", "-y"];
        for pkg in packages {
            args.push(pkg);
        }

        let result = self.run_apt_with_password(&args, password);
        self.installed_cache.invalidate();
        result
    }

    fn uninstall(&self, packages: &[String]) -> Result<(), PackageError> {
        if packages.is_empty() {
            return Ok(());
        }

        let mut args = vec!["remove", "-y"];
        for pkg in packages {
            args.push(pkg);
        }

        let result = self.run_apt(&args);
        self.installed_cache.invalidate();
        result
    }

    fn is_installed(&self, package: &str) -> Result<bool, PackageError> {
        self.installed_cache.contains(package, Self::load_installed)
    }

    fn update(&self) -> Result<(), PackageError> {
        self.run_apt(&["update"])
    }

    fn upgrade(&self) -> Result<(), PackageError> {
        self.run_apt(&["upgrade", "-y"])
    }
}

impl Default for Apt {
    fn default() -> Self {
        Self::new()
    }
}