Function build_batch_install 

pub fn build_batch_install<S: BuildHasher>(
    targets: &[PackageRef],
    helper: Option<AurHelper>,
    privilege: Option<PrivilegeTool>,
    options: &InstallOptions,
    installed: Option<&HashSet<String, S>>,
) -> Result<InstallPlan>

What: Plan a batch installation by splitting targets between pacman and an AUR helper.

Inputs:

• targets: Packages to install; the source field routes each to pacman or the helper.
• helper: AUR helper to use for AUR targets. Required when any target is from the AUR.
• privilege: When Some, the pacman command is wrapped (e.g., sudo pacman ...). AUR helper commands are never wrapped (helpers escalate internally).
• options: Flag options; options.needed is refined per group when installed is given.
• installed: Optional set of installed package names. When any name in a group is already installed, --needed is dropped for that group so reinstalls proceed — mirroring Pacsea’s batch reinstall detection. Pass None to use options.needed as-is.

Output:

• Ok(InstallPlan) with grouped commands and routed names.

Details:

• Official packages are grouped into a single pacman invocation, AUR packages into a single helper invocation (from Pacsea’s build_batch_install_command).
• Both grouped commands inherit strict name validation and the -- operand terminator from the underlying direct builders.
• Empty targets produces an empty plan (no error), so callers can pass through selection results unchecked.
• arch-toolkit never executes the plan; run the commands with spec.to_command() or display them with spec.to_shell_string() (dry run).

Errors

• ArchToolkitError::InvalidInput when AUR targets are present but helper is None.
• ArchToolkitError::InvalidPackageName when a target name fails validation.

Example

use arch_toolkit::install::build_batch_install;
use arch_toolkit::types::install::{AurHelper, InstallOptions, PrivilegeTool};
use arch_toolkit::{PackageRef, PackageSource};

let targets = vec![
    PackageRef::official("ripgrep", "14.0.0", "extra", "x86_64"),
    PackageRef::aur("yay-bin", "12.0.0"),
];
let plan = build_batch_install(
    &targets,
    Some(AurHelper::Paru),
    Some(PrivilegeTool::Sudo),
    &InstallOptions::default(),
    None::<&std::collections::HashSet<String>>,
)?;
assert_eq!(plan.commands.len(), 2);
assert_eq!(
    plan.commands[0].to_shell_string(),
    "sudo pacman -S --needed --noconfirm -- ripgrep"
);
assert_eq!(
    plan.commands[1].to_shell_string(),
    "paru -S --aur --needed --noconfirm -- yay-bin"
);