# Places operator-selected skills into each enabled agent's global skills
# directory, one per skill, for every project.
{
  config,
  lib,
  ...
}:
let
  cfg = config.programs.agents;
  claudeCode = config.programs.claude-code;
  pi = config.programs.pi-coding-agent;

  skillFiles = configDir:
    lib.listToAttrs (
      map (skill: {
        name = "${configDir}/skills/${skill.skillName}";
        value = {
          source = skill;
          recursive = true;
        };
      }) cfg.skills
    );
in
{
  options.programs.agents.skills = lib.mkOption {
    type = lib.types.listOf lib.types.package;
    default = [ ];
    example = lib.literalExpression "[ inputs.skills.packages.\${system}.some-skill ]";
    description = ''
      Skills to install globally into every enabled agent harness that supports
      Agent Skills.

      Selection is by derivation: pass skill derivations from the skills flake's
      `packages.<system>`, each of which carries its placement name as an
      eval-time attribute. An empty list installs nothing.

      Every skill is written as its own recursive {option}`home.file`, so this
      option composes with an operator's own harness-specific skills and with
      other modules placing skills under the same directory rather than claiming
      the tree. Placement is gated on each harness' enable option.
    '';
  };

  # `agents` is an umbrella namespace with no shared enable, so the skills
  # feature self-gates.
  # An empty list writes nothing, and files land only when a compatible harness
  # is enabled.
  # Reading each skill's source realises its derivation, so gating on harness
  # enablement also keeps that realisation off a host that installs nothing.
  config = lib.mkMerge [
    (lib.mkIf claudeCode.enable {
      # Each name is the derivation's eval-time `skillName`, so placement reads
      # no `$out` and needs no import-from-derivation.
      # `recursive = true` materialises `skills/<name>/` as a directory of
      # per-file symlinks, which lets this module, the operator's own skills,
      # and self-placing tool modules share one `skills/` tree.
      #
      # This deliberately does not feed the single-valued
      # `programs.claude-code.skills`, which would collide with an operator
      # already setting it.
      home.file = skillFiles claudeCode.configDir;
    })

    (lib.mkIf pi.enable {
      home.file = skillFiles pi.configDir;
    })
  ];
}