init.sh

#!/usr/bin/env bash
# knowledge-layer — scaffold the mechanical structure into a target repo.
# Idempotent and merge-aware: safe to re-run; never clobbles an existing
# knowledge/ or overwrites an existing .claude/settings.json (merges the hook).
#
# Usage: init.sh [repo-path]   (defaults to the git repo root, else $PWD)

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
ASSETS="$(dirname "$SCRIPT_DIR")/assets"

# --- locate the target repo ---------------------------------------------------
target="${1:-}"
if [ -z "$target" ]; then
  target="$(git rev-parse --show-toplevel 2>/dev/null || pwd)"
fi
cd "$target" || { echo "✗ cannot cd into $target" >&2; exit 1; }
echo "→ scaffolding knowledge layer into: $target"

# --- directories --------------------------------------------------------------
mkdir -p knowledge/wiki knowledge/journal knowledge/decisions .claude/hooks
echo "✓ knowledge/{wiki,journal,decisions} + .claude/hooks"

# --- breadcrumb hook ----------------------------------------------------------
cp "$ASSETS/journal-breadcrumb.sh" .claude/hooks/journal-breadcrumb.sh
chmod +x .claude/hooks/journal-breadcrumb.sh
echo "✓ .claude/hooks/journal-breadcrumb.sh"

# --- codemap refresh hook -----------------------------------------------------
cp "$ASSETS/codemap-refresh.sh" .claude/hooks/codemap-refresh.sh
chmod +x .claude/hooks/codemap-refresh.sh
echo "✓ .claude/hooks/codemap-refresh.sh"

# --- settings.json (merge both PostToolUse hooks, don't clobber) --------------
# Breadcrumb hook — emits the nudge agent note
CRUMB_BLOCK='{"matcher":"Bash","hooks":[{"type":"command","if":"Bash(git commit*)","command":"\"$CLAUDE_PROJECT_DIR/.claude/hooks/journal-breadcrumb.sh\"","timeout":15,"statusMessage":"Journaling commit…"}]}'
# Codemap refresh hook — regenerates the structural map in the background (no agent note)
CODEMAP_BLOCK='{"matcher":"Bash","hooks":[{"type":"command","if":"Bash(git commit*)","command":"\"$CLAUDE_PROJECT_DIR/.claude/hooks/codemap-refresh.sh\"","timeout":35,"statusMessage":"Refreshing code map…"}]}'
settings=".claude/settings.json"

merge_hook() {
  local settings="$1" block="$2"
  if [ -f "$settings" ]; then
    local tmp
    tmp="$(mktemp)"
    jq --argjson h "$block" '
      .hooks //= {} |
      .hooks.PostToolUse //= [] |
      if any(.hooks.PostToolUse[]?; (.hooks // [])[]?.command == ($h.hooks[0].command))
      then .
      else .hooks.PostToolUse += [$h] end
    ' "$settings" > "$tmp" && mv "$tmp" "$settings"
  else
    jq -n --argjson h "$block" \
      '{"$schema":"https://json.schemastore.org/claude-code-settings.json","hooks":{"PostToolUse":[$h]}}' \
      > "$settings"
  fi
}

merge_hook "$settings" "$CRUMB_BLOCK"
merge_hook "$settings" "$CODEMAP_BLOCK"
echo "✓ merged hooks into $settings"

# --- gitignore the hook's local state ----------------------------------------
ignore=".gitignore"
if ! { [ -f "$ignore" ] && grep -q 'knowledge/journal/.last-breadcrumb' "$ignore"; }; then
  printf '\n# knowledge-layer breadcrumb hook state\nknowledge/journal/.last-breadcrumb\n' >> "$ignore"
  echo "✓ gitignored knowledge/journal/.last-breadcrumb"
fi

# --- union merge-driver for generated codemap files --------------------------
# Generated files must never throw merge conflicts — git's built-in union driver
# lets each branch's lines union, and the next commit's hook regenerates a clean file.
git config merge.union.name "union merge driver" 2>/dev/null || true
git config merge.union.driver "true" 2>/dev/null || true

attrs=".gitattributes"
if ! { [ -f "$attrs" ] && grep -q 'knowledge/wiki/_codemap.md' "$attrs"; }; then
  {
    printf '\n# knowledge-layer generated files — union merge to avoid conflicts\n'
    printf 'knowledge/wiki/_codemap.md merge=union\n'
    printf 'knowledge/_codemap.json merge=union\n'
  } >> "$attrs"
  echo "✓ .gitattributes union merge-driver for _codemap.md + _codemap.json"
fi

# --- gitignore the generated codemap files -----------------------------------
# They are always regeneratable so we commit them if the project wants, but
# the project may opt out; ensure at minimum the .last-codemap state is ignored.
# (Projects may commit the codemap itself — it diffs cleanly; up to the project.)
if ! { [ -f "$ignore" ] && grep -q 'knowledge/journal/.last-codemap' "$ignore"; }; then
  printf '# knowledge-layer codemap hook state\nknowledge/journal/.last-codemap\n' >> "$ignore"
  echo "✓ gitignored knowledge/journal/.last-codemap"
fi

# --- template knowledge/CLAUDE.md (only if absent) ---------------------------
if [ -f knowledge/CLAUDE.md ]; then
  echo "• knowledge/CLAUDE.md already exists — left untouched"
else
  cp "$ASSETS/knowledge-CLAUDE.md.tmpl" knowledge/CLAUDE.md
  echo "✓ knowledge/CLAUDE.md (TEMPLATE — fill in the {{PLACEHOLDERS}})"
fi

cat <<'EOF'

Mechanical scaffold complete. Next (the agent does these):
  1. Fill the {{PLACEHOLDERS}} in knowledge/CLAUDE.md with real project context.
  2. Seed decisions/ + a backfill journal entry from the project's current state.
  3. Point the repo-root CLAUDE.md / README at knowledge/CLAUDE.md.
  4. Run the code-map generator to build the initial structural index:
       uv run --with tree-sitter --with tree-sitter-language-pack \
           python3 ~/.claude/skills/knowledge-layer/scripts/codemap.py [repo-root]
  5. Activate the hooks: open /hooks once, or restart the session.
EOF