#!/usr/bin/env bash
# gstack-gbrain-source-wireup — register the gstack brain repo as a gbrain
# federated source via `git worktree`, run an initial sync, hook into
# subsequent skill-end syncs.
#
# Replaces the v1.12.2.0 dead `consumers.json + ingest_url + /ingest-repo`
# wireup which depended on a gbrain HTTP endpoint that never shipped.
#
# Usage:
#   gstack-gbrain-source-wireup [--strict] [--source-id <id>] [--no-pull]
#   gstack-gbrain-source-wireup --uninstall [--source-id <id>]
#   gstack-gbrain-source-wireup --probe
#   gstack-gbrain-source-wireup --help
#
# Exit codes:
#   0 — success, OR benign skip without --strict
#   1 — hard failure (gbrain or git op errored on a real call)
#   2 — missing prereqs (no gbrain >= 0.18.0, no .git or remote-file)
#   3 — source-id derivation failed in --uninstall, no fallback worked
#
# Env:
#   GSTACK_HOME — override ~/.gstack (test harness)
#   GSTACK_BRAIN_WORKTREE — override worktree path (default ~/.gstack-brain-worktree)
#   GSTACK_BRAIN_SOURCE_ID — id override; --source-id flag takes precedence
#   GSTACK_BRAIN_NO_SYNC — skip the gbrain sync step (tests; helper still
#                          ensures source registration)
#
# Depends on: jq (transitive via gstack-gbrain-detect).

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
CONFIG_BIN="$SCRIPT_DIR/gstack-config"

GSTACK_HOME="${GSTACK_HOME:-$HOME/.gstack}"
WORKTREE="${GSTACK_BRAIN_WORKTREE:-$HOME/.gstack-brain-worktree}"
REMOTE_FILE="$HOME/.gstack-brain-remote.txt"
PLIST_PATH="$HOME/Library/LaunchAgents/com.gstack.brain-sync.plist"

# ---- arg parse ----
MODE="wireup"
STRICT=0
NO_PULL=0
SOURCE_ID=""

while [ $# -gt 0 ]; do
  case "$1" in
    --uninstall)   MODE="uninstall"; shift ;;
    --probe)       MODE="probe"; shift ;;
    --strict)      STRICT=1; shift ;;
    --no-pull)     NO_PULL=1; shift ;;
    --source-id)   SOURCE_ID="$2"; shift 2 ;;
    --help|-h)     sed -n '2,28p' "$0" | sed 's/^# \{0,1\}//'; exit 0 ;;
    *)             echo "Unknown flag: $1" >&2; exit 1 ;;
  esac
done

prefix() { sed 's/^/gstack-gbrain-source-wireup: /' >&2; }
warn()   { echo "$*" | prefix; }
die()    { warn "$*"; exit "${2:-1}"; }

# ---- source-id derivation (D6 multi-fallback) ----
derive_source_id() {
  if [ -n "$SOURCE_ID" ]; then
    echo "$SOURCE_ID"; return 0
  fi
  if [ -n "${GSTACK_BRAIN_SOURCE_ID:-}" ]; then
    echo "$GSTACK_BRAIN_SOURCE_ID"; return 0
  fi
  local remote_url=""
  remote_url=$(git -C "$GSTACK_HOME" remote get-url origin 2>/dev/null) || true
  if [ -z "$remote_url" ] && [ -f "$REMOTE_FILE" ]; then
    remote_url=$(head -1 "$REMOTE_FILE" 2>/dev/null | tr -d '[:space:]')
  fi
  [ -z "$remote_url" ] && return 3
  basename "$remote_url" .git \
    | tr '[:upper:]' '[:lower:]' \
    | tr -c 'a-z0-9-' '-' \
    | sed 's/--*/-/g; s/^-//; s/-$//' \
    | cut -c1-32
}

# ---- gbrain version gate ----
gbrain_version_ok() {
  if ! command -v gbrain >/dev/null 2>&1; then
    return 1
  fi
  local v
  v=$(gbrain --version 2>/dev/null | awk '{print $2}')
  [ -z "$v" ] && return 1
  # 0.18.0 minimum (gbrain sources shipped here)
  [ "$(printf '%s\n0.18.0\n' "$v" | sort -V | head -1)" = "0.18.0" ]
}

# ---- worktree management ----
# A worktree is always created `--detach`ed at $GSTACK_HOME's HEAD. Detached
# because a branch (main) can only be checked out in ONE worktree, and the
# parent at $GSTACK_HOME already has it. To advance, we re-checkout the
# parent's current HEAD into the detached worktree.
_worktree_add_detached() {
  local sha
  sha=$(git -C "$GSTACK_HOME" rev-parse HEAD 2>/dev/null) || return 1
  git -C "$GSTACK_HOME" worktree prune 2>/dev/null || true
  git -C "$GSTACK_HOME" worktree add --detach "$WORKTREE" "$sha" 2>/dev/null
}

ensure_worktree() {
  if [ ! -d "$GSTACK_HOME/.git" ]; then
    return 2
  fi
  if [ -d "$WORKTREE/.git" ] || [ -f "$WORKTREE/.git" ]; then
    # already exists; advance the detached HEAD to parent's current HEAD
    if [ "$NO_PULL" = "0" ]; then
      local sha
      sha=$(git -C "$GSTACK_HOME" rev-parse HEAD 2>/dev/null) || return 1
      ( cd "$WORKTREE" && git checkout --detach "$sha" 2>/dev/null ) || {
        warn "worktree at $WORKTREE could not advance to $sha; resetting via remove + re-add"
        git -C "$GSTACK_HOME" worktree remove --force "$WORKTREE" 2>/dev/null || rm -rf "$WORKTREE"
        _worktree_add_detached || return 1
      }
    fi
    return 0
  fi
  # Stray non-git dir? Remove first.
  [ -e "$WORKTREE" ] && rm -rf "$WORKTREE"
  _worktree_add_detached || return 1
}

# ---- gbrain sources operations ----
# Returns 0 if source with id exists at expected path. 1 if exists but path differs. 2 if absent.
check_source_state() {
  local id="$1"
  local existing_path
  existing_path=$(gbrain sources list --json 2>/dev/null \
    | jq -r --arg id "$id" '.sources[] | select(.id==$id) | .local_path' 2>/dev/null) || existing_path=""
  if [ -z "$existing_path" ]; then
    return 2
  fi
  if [ "$existing_path" = "$WORKTREE" ]; then
    return 0
  fi
  return 1
}

# ---- modes ----
do_probe() {
  local id worktree_status="absent" gbrain_status="missing" source_status="absent"
  id=$(derive_source_id 2>/dev/null) || id="(unknown)"
  [ -d "$WORKTREE/.git" ] || [ -f "$WORKTREE/.git" ] && worktree_status="present"
  if gbrain_version_ok; then
    gbrain_status="ok ($(gbrain --version 2>/dev/null | awk '{print $2}'))"
    if check_source_state "$id"; then
      source_status="registered ($WORKTREE)"
    elif [ $? = 1 ]; then
      source_status="registered (different path)"
    fi
  fi
  echo "source_id=$id"
  echo "worktree=$WORKTREE"
  echo "worktree_status=$worktree_status"
  echo "gbrain=$gbrain_status"
  echo "source_status=$source_status"
}

do_wireup() {
  local id
  id=$(derive_source_id) || die "cannot derive source id (no .git, no remote-file, no --source-id)" 2

  if ! gbrain_version_ok; then
    if [ "$STRICT" = "1" ]; then
      die "gbrain not installed or < 0.18.0; install/upgrade gbrain and re-run" 2
    fi
    warn "gbrain not installed or < 0.18.0; skipping wireup (benign skip)"
    exit 0
  fi

  ensure_worktree || {
    if [ $? = 2 ]; then
      [ "$STRICT" = "1" ] && die "no $GSTACK_HOME/.git; run /setup-gbrain Step 7 (gstack-brain-init) first" 2
      warn "no $GSTACK_HOME/.git; skipping (benign skip)"
      exit 0
    fi
    die "git worktree creation failed at $WORKTREE" 1
  }

  # Source registration: probe state, then act.
  set +e
  check_source_state "$id"
  local sstate=$?
  set -e
  case "$sstate" in
    0) : ;;  # already correctly registered
    1)
      warn "source $id registered with different path; recreating (gbrain has no 'sources update')"
      gbrain sources remove "$id" --yes 2>&1 | prefix || die "gbrain sources remove failed" 1
      gbrain sources add "$id" --path "$WORKTREE" --federated 2>&1 | prefix \
        || die "gbrain sources add failed" 1
      ;;
    2)
      gbrain sources add "$id" --path "$WORKTREE" --federated 2>&1 | prefix \
        || die "gbrain sources add failed" 1
      ;;
  esac

  if [ "${GSTACK_BRAIN_NO_SYNC:-0}" = "1" ]; then
    echo "source_id=$id"
    echo "worktree=$WORKTREE"
    echo "pages_synced=skipped"
    exit 0
  fi

  local sync_out
  sync_out=$(gbrain sync --repo "$WORKTREE" 2>&1) || die "gbrain sync failed: $sync_out" 1
  echo "$sync_out" | tail -3 | prefix

  echo "source_id=$id"
  echo "worktree=$WORKTREE"
  echo "pages_synced=$(echo "$sync_out" | grep -oE '[0-9]+ pages? imported' | head -1 || echo 'incremental')"
}

do_uninstall() {
  local id
  id=$(derive_source_id) || die "cannot derive source id; pass --source-id <id> explicitly" 3

  if command -v gbrain >/dev/null 2>&1; then
    gbrain sources remove "$id" --yes 2>&1 | prefix || warn "gbrain sources remove failed (continuing)"
  fi

  if [ -d "$WORKTREE/.git" ] || [ -f "$WORKTREE/.git" ]; then
    git -C "$GSTACK_HOME" worktree remove --force "$WORKTREE" 2>/dev/null \
      || rm -rf "$WORKTREE"
  fi

  # Cron-stub: future launchd plist (not created today; safety net for D9 future).
  rm -f "$PLIST_PATH" 2>/dev/null || true

  echo "uninstalled source=$id worktree=$WORKTREE"
}

case "$MODE" in
  probe)     do_probe ;;
  wireup)    do_wireup ;;
  uninstall) do_uninstall ;;
esac