#!/usr/bin/env bash
set -euo pipefail
#
# ops/install-hook.sh — idempotently register the toknmtr capture hook
# (agent/hooks/toknmtr-capture.sh) in ~/.claude/settings.json under the Claude Code 'Stop'
# hook event.
#
# WHY 'Stop' AND NOT 'SessionEnd':
#   Stop fires at the end of EVERY assistant turn (each time Claude finishes responding and
#   yields back to the user) — not just once when the whole CLI process exits. That makes
#   capture close to live: a dashboard refresh a few seconds after a turn already reflects
#   it. The cost is the hook running more often, but agent/hooks/toknmtr-capture.sh is
#   designed to be near-zero-cost on the foreground session (it backgrounds the real work
#   and returns in milliseconds — see that script's header), so the extra frequency is
#   nearly free.
#   SessionEnd only fires once, when the CLI process actually exits — on a long interactive
#   session that can be hours after the data was generated, and Claude Code does not
#   guarantee SessionEnd fires on every exit path (e.g. a killed/crashed terminal can skip
#   it entirely), so relying on it alone risks losing the tail of a session permanently
#   until the next cron sweep (ops/install-cron.sh) catches it.
#   Net: Stop is the better default given the hook is cheap. The cron sweep is an
#   independent safety net either way (server-down resilience, missed hook fires, etc.) —
#   it doesn't change this tradeoff, it just makes the choice lower-stakes. Revisit by
#   swapping HOOK_EVENT below to "SessionEnd" if Stop's per-turn frequency ever proves to be
#   a real problem in practice (e.g. very chatty multi-turn sessions on a slow machine).
#
# What this script does:
#   - Merges (via jq) a Stop-hook entry pointing at agent/hooks/toknmtr-capture.sh into
#     ~/.claude/settings.json, WITHOUT touching any other keys/hooks already in that file.
#   - Idempotent: matches on the exact command string, so re-running is a safe no-op.
#   - Writes a timestamped backup of settings.json before every modification.
#   - Reversible: `ops/install-hook.sh --remove` undoes just this hook's entry (or restore
#     a backup manually — see the "to remove later" line this script prints on install).
#
# Usage:
#   ops/install-hook.sh            # install/update the hook
#   ops/install-hook.sh --remove   # remove this hook's entry from settings.json
#
# Override knobs (env, all optional):
#   TOKNMTR_PROJECT_DIR    path to the toknmtr repo checkout (default: ~/claude/projects/toknmtr)
#   CLAUDE_SETTINGS_FILE   path to settings.json             (default: ~/.claude/settings.json)

PROJECT_DIR="${TOKNMTR_PROJECT_DIR:-$HOME/claude/projects/toknmtr}"
SETTINGS_FILE="${CLAUDE_SETTINGS_FILE:-$HOME/.claude/settings.json}"
HOOK_SCRIPT="$PROJECT_DIR/agent/hooks/toknmtr-capture.sh"
HOOK_EVENT="Stop"
HOOK_CMD="bash \"$HOOK_SCRIPT\""
HOOK_TIMEOUT_S=10

command -v jq >/dev/null 2>&1 || {
	echo "error: jq is required (sudo apt install jq / brew install jq)" >&2
	exit 1
}

backup_settings() {
	[ -f "$SETTINGS_FILE" ] || return 0
	local stamp
	stamp="$(date +%Y%m%dT%H%M%S)"
	cp "$SETTINGS_FILE" "$SETTINGS_FILE.bak.$stamp"
	echo "backed up $SETTINGS_FILE -> $SETTINGS_FILE.bak.$stamp"
}

if [ "${1:-}" = "--remove" ]; then
	if [ ! -f "$SETTINGS_FILE" ]; then
		echo "no settings file at $SETTINGS_FILE, nothing to remove"
		exit 0
	fi
	backup_settings
	tmp="$(mktemp)"
	jq --arg cmd "$HOOK_CMD" --arg event "$HOOK_EVENT" '
    if (.hooks // {} | has($event)) then
      .hooks[$event] = [
        .hooks[$event][] |
        .hooks = [(.hooks // [])[] | select(.command != $cmd)] |
        select((.hooks | length) > 0)
      ]
    else . end
  ' "$SETTINGS_FILE" >"$tmp" && mv "$tmp" "$SETTINGS_FILE"
	echo "removed toknmtr capture hook from $SETTINGS_FILE.$HOOK_EVENT (backup written above; other $HOOK_EVENT hooks, if any, were left untouched)"
	exit 0
fi

if [ ! -f "$HOOK_SCRIPT" ]; then
	echo "error: $HOOK_SCRIPT not found (is TOKNMTR_PROJECT_DIR=$PROJECT_DIR correct?)" >&2
	exit 1
fi
chmod +x "$HOOK_SCRIPT" 2>/dev/null || true

mkdir -p "$(dirname "$SETTINGS_FILE")"
[ -f "$SETTINGS_FILE" ] || echo '{}' >"$SETTINGS_FILE"
jq empty "$SETTINGS_FILE" || {
	echo "error: $SETTINGS_FILE is not valid JSON — fix it manually before running this script" >&2
	exit 1
}

backup_settings

tmp="$(mktemp)"
jq --arg cmd "$HOOK_CMD" --arg event "$HOOK_EVENT" --argjson timeout "$HOOK_TIMEOUT_S" '
  .hooks //= {} |
  .hooks[$event] //= [] |
  ([.hooks[$event][]? | (.hooks // [])[]? | .command] | index($cmd)) as $already |
  if $already == null then
    .hooks[$event] += [{"hooks": [{"type": "command", "command": $cmd, "timeout": $timeout}]}]
  else . end
' "$SETTINGS_FILE" >"$tmp" && mv "$tmp" "$SETTINGS_FILE"

echo "installed toknmtr capture hook into $SETTINGS_FILE under hooks.$HOOK_EVENT"
echo "  command: $HOOK_CMD"
echo ""
echo "to remove later:"
echo "  ops/install-hook.sh --remove"
echo "  (or restore a $SETTINGS_FILE.bak.<timestamp> file written next to it)"