# Runs the dev-shell helper's hook against a fixture project and asserts the
# placement, stateless stale-removal, and hand-authored-skill safety it promises.
{
  pkgs,
  mkSkill,
  mkSkillsShellHook,
}:
let
  # Sample skills built through the flake's own `mkSkill`, so they carry the
  # `skillName` passthru the hook reads and land at real store paths the hook
  # can link to.
  mkSampleSkill =
    name:
    mkSkill {
      inherit pkgs name;
      src = pkgs.runCommandLocal "${name}-src" { } ''
        mkdir -p "$out"
        printf '%s\n' "sample skill ${name}" > "$out/SKILL.md"
      '';
    };

  skillAlpha = mkSampleSkill "sample-alpha";
  skillBeta = mkSampleSkill "sample-beta";
  # Selected, but a hand-authored real directory of the same name already exists
  # in the fixture, so the hook must skip it.
  skillGamma = mkSampleSkill "sample-gamma";

  # Two hooks for two successive selections: the second drops sample-beta, so
  # sourcing it after the first proves a deselected skill's symlink is removed.
  hookBoth = mkSkillsShellHook [
    skillAlpha
    skillBeta
    skillGamma
  ];
  hookAlpha = mkSkillsShellHook [ skillAlpha ];
in
pkgs.runCommandLocal "skills-shell-hook-check"
  {
    inherit hookBoth hookAlpha;
    alphaPath = "${skillAlpha}";
    betaPath = "${skillBeta}";
  }
  ''
    fail() { echo "FAIL: $1" >&2; exit 1; }

    echo "the hook is a non-empty string referencing each skill's store path and name"
    [ -n "$hookBoth" ] || fail "the produced hook is empty"
    for token in "$alphaPath" "$betaPath" sample-alpha sample-beta; do
      printf '%s' "$hookBoth" | grep -qF "$token" \
        || fail "the hook does not reference $token"
    done

    # The fixture project carries three things the hook must not disturb: a
    # hand-authored skill under its own name, a hand-authored skill whose name
    # collides with a selected one, and a symlink pointing outside the store.
    mkdir -p proj/.agents/skills/handmade
    printf '%s\n' "a hand-authored skill" > proj/.agents/skills/handmade/SKILL.md
    printf '%s\n' "# fixture ignore" "result" > proj/.gitignore
    mkdir -p proj/.agents/skills/sample-gamma
    printf '%s\n' "a hand-authored gamma" > proj/.agents/skills/sample-gamma/SKILL.md
    ln -s /nonexistent/external-target proj/.agents/skills/external
    cd proj

    echo "first entry: the two free skills link as store symlinks that resolve"
    printf '%s\n' "$hookBoth" > ../hook-both.sh
    . ../hook-both.sh
    for name in sample-alpha sample-beta; do
      [ -L ".agents/skills/$name" ] || fail "$name was not linked as a symlink"
      case "$(readlink ".agents/skills/$name")" in
        ${builtins.storeDir}/*) : ;;
        *) fail "$name's symlink does not point into the store" ;;
      esac
      test -f ".agents/skills/$name/SKILL.md" \
        || fail "$name's link does not resolve to its SKILL.md"
    done

    echo "a selected skill colliding with a hand-authored one leaves the real directory"
    { [ -d .agents/skills/sample-gamma ] && [ ! -L .agents/skills/sample-gamma ]; } \
      || fail "the colliding hand-authored skill was replaced by a symlink"
    grep -qx "a hand-authored gamma" .agents/skills/sample-gamma/SKILL.md \
      || fail "the colliding hand-authored skill's content was overwritten"

    echo "the non-colliding hand-authored skill is an untouched real directory"
    { [ -d .agents/skills/handmade ] && [ ! -L .agents/skills/handmade ]; } \
      || fail "the hand-authored skill was replaced or removed"
    test -f .agents/skills/handmade/SKILL.md || fail "the hand-authored skill lost its content"

    echo "a symlink pointing outside the store is not ours, so it is left alone"
    [ -L .agents/skills/external ] || fail "the non-store symlink was removed"

    echo "Claude Code compatibility points at the canonical skill directory"
    [ -L .claude/skills ] || fail ".claude/skills is not a compatibility symlink"
    [ "$(readlink .claude/skills)" = "../.agents/skills" ] \
      || fail ".claude/skills points somewhere other than ../.agents/skills"
    test -f .claude/skills/sample-alpha/SKILL.md \
      || fail "Claude Code compatibility link does not resolve selected skills"

    echo "the project .gitignore lists only generated links and keeps skill scanners clear"
    test ! -e .agents/skills/.gitignore || fail "the hook wrote an ignore file where skill scanners read it"
    grep -qx '# fixture ignore' .gitignore || fail "the existing .gitignore content was lost"
    grep -qx 'result' .gitignore || fail "the existing .gitignore pattern was lost"
    grep -qx '# BEGIN mkSkillsShellHook' .gitignore || fail ".gitignore lacks the managed block start"
    grep -qx '# END mkSkillsShellHook' .gitignore || fail ".gitignore lacks the managed block end"
    grep -qx '.claude/skills' .gitignore || fail ".gitignore omits the compatibility symlink"
    grep -qx '.agents/skills/sample-alpha' .gitignore || fail ".gitignore omits sample-alpha"
    grep -qx '.agents/skills/sample-beta' .gitignore || fail ".gitignore omits sample-beta"
    for tracked in .agents/skills/handmade .agents/skills/sample-gamma .agents/skills/external; do
      grep -qx "$tracked" .gitignore \
        && fail ".gitignore lists $tracked, which would untrack a real path"
    done

    echo "no manifest or state file is written: only the fixtures and links exist"
    entries=$(ls -A .agents/skills | sort | tr '\n' ' ')
    [ "$entries" = "external handmade sample-alpha sample-beta sample-gamma " ] \
      || fail "unexpected entries under .agents/skills: [$entries]"

    echo "second entry with sample-beta deselected: its symlink is removed, the rest stay"
    printf '%s\n' "$hookAlpha" > ../hook-alpha.sh
    . ../hook-alpha.sh
    test ! -e .agents/skills/sample-beta || fail "the deselected skill's symlink was not removed"
    [ -L .agents/skills/sample-alpha ] || fail "the still-selected skill was dropped"
    { [ -d .agents/skills/handmade ] && [ ! -L .agents/skills/handmade ]; } \
      || fail "the hand-authored skill was disturbed on re-entry"
    { [ -d .agents/skills/sample-gamma ] && [ ! -L .agents/skills/sample-gamma ]; } \
      || fail "the colliding hand-authored skill was disturbed on re-entry"
    [ -L .agents/skills/external ] || fail "the non-store symlink was disturbed on re-entry"

    echo "the .gitignore tracks the new selection without duplicating the managed block"
    grep -qx '.agents/skills/sample-alpha' .gitignore || fail ".gitignore lost sample-alpha"
    grep -qx '.agents/skills/sample-beta' .gitignore \
      && fail ".gitignore still lists the deselected sample-beta"
    [ "$(grep -xc '# BEGIN mkSkillsShellHook' .gitignore)" = 1 ] \
      || fail ".gitignore has duplicate managed blocks"

    touch "$out"
  ''