#!/usr/bin/env bash
# red-gradle — built-in pre_worktree library hook for Gradle projects.
#
# Contract (ADR 0026, PRD #207, issue #211):
#   stdin   — JSON object: pre_worktree context (issue, target, branch, env).
#   applicability — decided by the Node resolver before this leaf runs.
#   stdout  — empty (context unchanged) when RED_AFK_GRADLE_USER_HOME_BASE is
#             unset (opt-in by env var — we do not claim a path on the user's
#             filesystem without their consent). Otherwise a JSON object
#             that merges {env: {GRADLE_USER_HOME: <slot dir>}} into ctx.
#   exit    — 0 on either branch. Never aborts the chain.
#
# Side effect: mkdir -p the slot Gradle home so daemons / caches are isolated
# between worker slots.
#
# Env contract (RED_AFK_* exported by the orchestrator):
#   RED_AFK_SLOT                   — worker slot number (0-based); defaults to 0.
#   RED_AFK_GRADLE_USER_HOME_BASE  — base dir for per-slot Gradle homes;
#                                    UNSET by default (opt-in). Set in
#                                    .red/config.yaml or by environment to
#                                    activate per-slot Gradle isolation.
#
# Shadowing: place a same-named file in .red/hooks/red-gradle to replace this
# default with a project-local variant. An empty (exit-0) file disables it.

set -u

ctx="$(timeout "${RED_SKILLS_HOOK_STDIN_TIMEOUT_S:-5s}" cat 2>/dev/null || true)"
[ -n "$ctx" ] || ctx='{}'

if [ -z "${RED_AFK_GRADLE_USER_HOME_BASE:-}" ]; then
  exit 0
fi

slot="${RED_AFK_SLOT:-0}"
home_dir="${RED_AFK_GRADLE_USER_HOME_BASE}/slot-${slot}"

mkdir -p "$home_dir" 2>/dev/null || true

printf '%s' "$ctx" | jq -c \
  --arg h "$home_dir" \
  '. + {env: ((.env // {}) + {GRADLE_USER_HOME: $h})}'