#!/usr/bin/env bash
# gstack-brain-init — set up ~/.gstack/ as a git repo that syncs to GBrain.
#
# Usage:
#   gstack-brain-init [--remote <url>]
#
# Interactive by default. Pass --remote to skip the remote prompt.
#
# Idempotent: safe to re-run. If ~/.gstack/.git already exists AND points at
# the same remote, reconfigures drivers/hooks/attributes without clobbering
# history. If it points at a DIFFERENT remote, refuses and suggests
# `gstack-brain-uninstall` first.
#
# What it does:
#   1. git init ~/.gstack/  (or verify existing repo points at the right remote)
#   2. Write .gitignore = "*"  (ignore everything; allowlist is explicit)
#   3. Write .brain-allowlist  (canonical paths to sync)
#   4. Write .brain-privacy-map.json  (paths → privacy class)
#   5. Write .gitattributes  (register JSONL + union merge drivers)
#   6. git config  merge.jsonl-append.driver + merge.union.driver
#   7. Install .git/hooks/pre-commit  (defense-in-depth secret scan)
#   8. Prompt for remote (default: gh repo create --private gstack-brain-$USER)
#   9. Initial commit + push
#   10. Write ~/.gstack-brain-remote.txt  (URL-only, safe to share)
#
# Env:
#   GSTACK_HOME — override ~/.gstack

set -euo pipefail

GSTACK_HOME="${GSTACK_HOME:-$HOME/.gstack}"
SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
CONFIG_BIN="$SCRIPT_DIR/gstack-config"
REMOTE_FILE="$HOME/.gstack-brain-remote.txt"

REMOTE_URL=""
while [ $# -gt 0 ]; do
  case "$1" in
    --remote) REMOTE_URL="$2"; shift 2 ;;
    --help|-h) sed -n '2,32p' "$0" | sed 's/^# \{0,1\}//'; exit 0 ;;
    *) echo "Unknown flag: $1" >&2; exit 1 ;;
  esac
done

# ---- preconditions ----
mkdir -p "$GSTACK_HOME"

EXISTING_REMOTE=""
if [ -d "$GSTACK_HOME/.git" ]; then
  EXISTING_REMOTE=$(git -C "$GSTACK_HOME" remote get-url origin 2>/dev/null || echo "")
  if [ -n "$EXISTING_REMOTE" ] && [ -n "$REMOTE_URL" ] && [ "$EXISTING_REMOTE" != "$REMOTE_URL" ]; then
    cat >&2 <<EOF
gstack-brain-init: ~/.gstack/ is already a git repo pointing at:
  $EXISTING_REMOTE

You asked to init with:
  $REMOTE_URL

Refusing to overwrite. To switch remotes, first run:
  gstack-brain-uninstall

(or edit the remote manually with: git -C ~/.gstack remote set-url origin <url>)
EOF
    exit 1
  fi
fi

# ---- choose the remote ----
if [ -z "$REMOTE_URL" ] && [ -n "$EXISTING_REMOTE" ]; then
  REMOTE_URL="$EXISTING_REMOTE"
  echo "Using existing remote: $REMOTE_URL"
fi

if [ -z "$REMOTE_URL" ]; then
  # Interactive prompt. Default: gh repo create (if available).
  echo "gstack-brain-init will create a private git repo that holds your"
  echo "gstack session memory across machines and lets GBrain index it."
  echo
  if command -v gh >/dev/null 2>&1 && gh auth status >/dev/null 2>&1; then
    DEFAULT_NAME="gstack-brain-${USER:-$(whoami)}"
    echo "Default: gh will create a private repo named '$DEFAULT_NAME' under your account."
    printf "Press Enter to accept, or paste a custom git URL: "
    read -r REPLY || REPLY=""
    if [ -z "$REPLY" ]; then
      echo "Creating GitHub repo: $DEFAULT_NAME ..."
      # Note: --source omitted intentionally. gh requires --source to point at
      # an existing git repo, but we don't init $GSTACK_HOME until after the
      # remote is chosen. Create bare, then fetch URL.
      if ! gh repo create "$DEFAULT_NAME" --private --description "gstack session memory" 2>/dev/null; then
        # Maybe the repo already exists; try to fetch its URL.
        REMOTE_URL=$(gh repo view "$DEFAULT_NAME" --json sshUrl -q .sshUrl 2>/dev/null || echo "")
        if [ -z "$REMOTE_URL" ]; then
          echo "Failed to create or find '$DEFAULT_NAME'. Try --remote <url>." >&2
          exit 1
        fi
        echo "Repo already exists; using $REMOTE_URL"
      else
        REMOTE_URL=$(gh repo view "$DEFAULT_NAME" --json sshUrl -q .sshUrl 2>/dev/null || echo "")
      fi
    else
      REMOTE_URL="$REPLY"
    fi
  else
    echo "(gh CLI not found or not authenticated; provide a git URL directly)"
    printf "Paste a private git URL (e.g. git@github.com:you/gstack-brain.git): "
    read -r REMOTE_URL || REMOTE_URL=""
    if [ -z "$REMOTE_URL" ]; then
      echo "No URL provided. Aborting." >&2
      exit 1
    fi
  fi
fi

# ---- verify remote reachable ----
echo "Verifying remote connectivity: $REMOTE_URL"
if ! git ls-remote "$REMOTE_URL" >/dev/null 2>&1; then
  cat >&2 <<EOF
Remote not reachable: $REMOTE_URL
This could mean:
  - Wrong URL
  - Not authenticated (GitHub: gh auth status; GitLab: glab auth status)
  - Network issue
Fix and re-run gstack-brain-init.
EOF
  exit 1
fi

# ---- git init ----
if [ ! -d "$GSTACK_HOME/.git" ]; then
  git -C "$GSTACK_HOME" init -q -b main 2>/dev/null || git -C "$GSTACK_HOME" init -q
  # If -b main wasn't supported, rename.
  git -C "$GSTACK_HOME" branch -M main 2>/dev/null || true
fi

if [ -z "$(git -C "$GSTACK_HOME" remote 2>/dev/null)" ]; then
  git -C "$GSTACK_HOME" remote add origin "$REMOTE_URL"
else
  git -C "$GSTACK_HOME" remote set-url origin "$REMOTE_URL"
fi

# ---- write canonical files (idempotent) ----
cat > "$GSTACK_HOME/.gitignore" <<'EOF'
# gstack-brain sync: ignore-everything base. Paths are included explicitly via
# .brain-allowlist and `git add -f` from gstack-brain-sync. Do not edit.
*
EOF

cat > "$GSTACK_HOME/.brain-allowlist" <<'EOF'
# Canonical allowlist of paths that gstack-brain-sync will publish.
# One glob per line. Anything not matching stays local.
# Do not edit directly; managed by gstack-brain-init. User additions go below
# the marker and survive re-init.
projects/*/learnings.jsonl
projects/*/*-reviews.jsonl
projects/*/ceo-plans/*.md
projects/*/ceo-plans/*/*.md
projects/*/designs/*.md
projects/*/designs/*/*.md
projects/*/timeline.jsonl
retros/*.md
developer-profile.json
builder-journey.md
builder-profile.jsonl
# NOT synced (per Codex v2 review — machine-local UX state):
#   projects/*/question-preferences.json (per-machine UX preferences)
#   projects/*/question-log.jsonl (audit/derivation log stays with preferences)
#   projects/*/question-events.jsonl (same)
# ---- USER ADDITIONS BELOW ---- (survives re-init; above is managed)
EOF

cat > "$GSTACK_HOME/.brain-privacy-map.json" <<'EOF'
[
  {"pattern": "projects/*/learnings.jsonl", "class": "artifact"},
  {"pattern": "projects/*/*-reviews.jsonl", "class": "artifact"},
  {"pattern": "projects/*/ceo-plans/*.md", "class": "artifact"},
  {"pattern": "projects/*/ceo-plans/*/*.md", "class": "artifact"},
  {"pattern": "projects/*/designs/*.md", "class": "artifact"},
  {"pattern": "projects/*/designs/*/*.md", "class": "artifact"},
  {"pattern": "retros/*.md", "class": "artifact"},
  {"pattern": "builder-journey.md", "class": "artifact"},
  {"pattern": "projects/*/timeline.jsonl", "class": "behavioral"},
  {"pattern": "developer-profile.json", "class": "behavioral"},
  {"pattern": "builder-profile.jsonl", "class": "behavioral"}
]
EOF

cat > "$GSTACK_HOME/.gitattributes" <<'EOF'
# gstack-brain: merge drivers for cross-machine sync conflicts.
# Matching driver must be registered in local git config; gstack-brain-init
# and gstack-brain-restore run `git config merge.<name>.driver ...` after init.
*.jsonl merge=jsonl-append
retros/*.md merge=union
projects/*/designs/**/*.md merge=union
projects/*/ceo-plans/**/*.md merge=union
EOF

# ---- register merge drivers in local git config ----
git -C "$GSTACK_HOME" config merge.jsonl-append.driver "$SCRIPT_DIR/gstack-jsonl-merge %O %A %B"
git -C "$GSTACK_HOME" config merge.jsonl-append.name "gstack JSONL append-only merger"
git -C "$GSTACK_HOME" config merge.union.driver "cat %A %B > %A.merged && mv %A.merged %A"
git -C "$GSTACK_HOME" config merge.union.name "union concat"

# ---- install pre-commit hook (defense-in-depth) ----
HOOK="$GSTACK_HOME/.git/hooks/pre-commit"
mkdir -p "$(dirname "$HOOK")"
cat > "$HOOK" <<'HOOK_EOF'
#!/usr/bin/env bash
# gstack-brain pre-commit hook — secret-scan defense-in-depth.
# The primary scanner runs inside gstack-brain-sync BEFORE staging. This hook
# catches any manual `git commit` a user might accidentally run against the
# brain repo.
set -uo pipefail

python3 -c "
import sys, re, subprocess
try:
    out = subprocess.check_output(['git', 'diff', '--cached'], stderr=subprocess.DEVNULL).decode('utf-8', 'replace')
except Exception:
    sys.exit(0)

patterns = [
    ('aws-access-key', re.compile(r'AKIA[0-9A-Z]{16}')),
    ('github-token', re.compile(r'\b(gh[pousr]_[A-Za-z0-9]{20,}|github_pat_[A-Za-z0-9_]{20,})')),
    ('openai-key', re.compile(r'\bsk-[A-Za-z0-9_-]{20,}')),
    ('pem-block', re.compile(r'-----BEGIN [A-Z ]{3,}-----')),
    ('jwt', re.compile(r'\beyJ[A-Za-z0-9_-]{10,}\.[A-Za-z0-9_-]{10,}\.[A-Za-z0-9_-]{10,}\b')),
    ('bearer-token-json',
     re.compile(r'\"(authorization|api[_-]?key|apikey|token|secret|password)\"\s*:\s*\"[A-Za-z0-9_./+=-]{16,}\"',
                re.IGNORECASE)),
]
for name, rx in patterns:
    if rx.search(out):
        sys.stderr.write(f'gstack-brain pre-commit: refusing commit — {name} detected in staged diff.\n')
        sys.stderr.write('Either edit the offending file, or if intentional, run:\n')
        sys.stderr.write('  gstack-brain-sync --skip-file <path>  (to permanently exclude)\n')
        sys.exit(1)
sys.exit(0)
"
HOOK_EOF
chmod +x "$HOOK"

# ---- initial commit (idempotent; skips if already committed) ----
cd "$GSTACK_HOME"
git add -f .gitignore .brain-allowlist .brain-privacy-map.json .gitattributes
# Only commit if the index has changes from HEAD (if there is a HEAD).
if git rev-parse HEAD >/dev/null 2>&1; then
  if ! git diff --cached --quiet 2>/dev/null; then
    git -c user.email="gstack@localhost" -c user.name="gstack-brain-init" \
        commit -q -m "chore: gstack-brain-init (refresh sync config)"
  fi
else
  # First commit ever.
  git -c user.email="gstack@localhost" -c user.name="gstack-brain-init" \
      commit -q -m "chore: gstack-brain-init"
fi

# ---- initial push ----
if ! git push -q -u origin main 2>/dev/null; then
  # Maybe the default branch is master, or the remote has existing content.
  # Try to resolve: fetch + fast-forward merge + push.
  CURRENT_BRANCH=$(git rev-parse --abbrev-ref HEAD)
  if git fetch origin 2>/dev/null && git pull --ff-only origin "$CURRENT_BRANCH" 2>/dev/null; then
    git push -q -u origin "$CURRENT_BRANCH" || {
      echo "Push to $REMOTE_URL failed. The remote may have divergent content." >&2
      echo "Try: cd ~/.gstack && git pull --rebase origin $CURRENT_BRANCH && git push origin $CURRENT_BRANCH" >&2
      exit 1
    }
  else
    # Couldn't fetch/merge; print what to do.
    echo "Push to $REMOTE_URL failed and fetch/merge didn't help." >&2
    echo "Manual recovery: cd ~/.gstack && git status, then push once conflicts are resolved." >&2
    exit 1
  fi
fi

# ---- write the remote-url helper file (outside ~/.gstack/, survives restore) ----
echo "$REMOTE_URL" > "$REMOTE_FILE"
chmod 600 "$REMOTE_FILE"

# ---- done ----
cat <<EOF

gstack-brain-init complete.
Repo:    $GSTACK_HOME (git)
Remote:  $REMOTE_URL
Remote URL also saved at: $REMOTE_FILE

Sync to GitHub happens automatically at the start and end of each skill
(no daemon). Check status anytime with:
  gstack-brain-sync --status

The next skill run will ask you one question about privacy mode (full /
artifacts-only / off). After that, /setup-gbrain Step 7 (or the
gstack-gbrain-source-wireup helper) registers this repo as a federated
source on gbrain so its content is searchable via 'gbrain search'.

New machine? On the other laptop, put a copy of:
  $REMOTE_FILE
in that machine's home directory, then run: gstack-brain-restore
EOF