#!/usr/bin/env bash
#
# tea-guard — PreToolUse hook for Bash commands.
#
# Enforces, deterministically, the one rule the prose in /tea:use cannot:
# every `tea` invocation that touches Gitea MUST carry --login "$GITEA_LOGIN",
# and $GITEA_LOGIN must be set. Without this, `tea` silently falls back to the
# machine's default login (often the user's personal account) and writes under
# the wrong identity.
#
# Exit codes: 0 = allow, 2 = block (stderr is fed back to Claude as the reason).
#
set -uo pipefail

input="$(cat)"

# Extract tool_input.command from the hook payload (jq if present, else python3).
if command -v jq >/dev/null 2>&1; then
  cmd="$(printf '%s' "$input" | jq -r '.tool_input.command // ""' 2>/dev/null || true)"
else
  cmd="$(printf '%s' "$input" | /usr/bin/python3 -c 'import sys,json; print(json.load(sys.stdin).get("tool_input",{}).get("command","") or "")' 2>/dev/null || true)"
fi

# Not a `tea` command → not our concern.
if ! printf '%s' "$cmd" | grep -Eq '(^|[;&|(]|[[:space:]])tea([[:space:]]|$)'; then
  exit 0
fi

# Whitelist: login enumeration + meta. These do not act under any identity and
# are needed by /tea:login itself (which runs while $GITEA_LOGIN may be unset).
if printf '%s' "$cmd" | grep -Eq 'tea[[:space:]]+(logins[[:space:]]+(list|ls)|--version|-v|--help|help)([[:space:]]|$)'; then
  exit 0
fi

# Require an explicit --login / -l on the invocation.
if ! printf '%s' "$cmd" | grep -Eq '(--login|[[:space:]]-l)([[:space:]=])'; then
  echo "tea-guard: BLOCKED — every 'tea' command must include --login \"\$GITEA_LOGIN\" (or -l). Run /tea:login to pin the project login, then retry. Only 'tea logins list' and 'tea --version/--help' are exempt." >&2
  exit 2
fi

# Require $GITEA_LOGIN to be set in the environment.
if [ -z "${GITEA_LOGIN:-}" ]; then
  echo "tea-guard: BLOCKED — \$GITEA_LOGIN is empty/unset, so --login \"\$GITEA_LOGIN\" would expand to nothing and tea would fall back to the default login. Run /tea:login to pin a login (writes .claude/settings.local.json), then restart the session so it is exported." >&2
  exit 2
fi

exit 0