#!/bin/bash
# Discourse SSO first-login via Cloudron OIDC (openid_connect).
# usage: discourse-sso-login.sh <cloudron-username> [vault-item]
# Verifies a logged-in session at /my/summary.
set -uo pipefail
U="${1:?usage: discourse-sso-login.sh <cloudron-username> [vault-item]}"
ITEM="${2:-$U Cloudron}"
BASE="https://community.turnsys.com"
IDP="https://my.knownelement.com"
JAR="/tmp/discourse-jar-$U.txt"; rm -f "$JAR"
SM() { if [ "$(id -un)" = "TSGCOO" ]; then /data2/TSGCOO/.local/bin/sm "$@" </dev/null; else sudo -u TSGCOO /data2/TSGCOO/.local/bin/sm "$@" </dev/null; fi; }
PW=$(SM get "$ITEM" --field password)
[ -n "$PW" ] || { echo "FAIL: no password in vault item $ITEM" >&2; exit 1; }
SEED=$(SM get "$ITEM" --field totp_seed 2>/dev/null || true)

# Discourse gates omniauth behind CSRF + a confirm page
CSRF=$(curl -sk -b "$JAR" -c "$JAR" -H 'X-Requested-With: XMLHttpRequest' "$BASE/session/csrf" | sed -n 's/.*"csrf":"\([^"]*\)".*/\1/p')
[ -n "$CSRF" ] || { echo "FAIL: no csrf token" >&2; exit 2; }
CONFIRM_HTML=$(curl -sk -b "$JAR" -c "$JAR" -H "X-CSRF-Token: $CSRF" -H 'X-Requested-With: XMLHttpRequest' "$BASE/auth/oidc")
FORMTOKEN=$(printf '%s' "$CONFIRM_HTML" | grep -o 'name="authenticity_token"[^>]*value="[^"]*"' | head -1 | sed 's/.*value="//; s/"$//')
[ -n "$FORMTOKEN" ] || { echo "FAIL: no confirm form token" >&2; exit 2; }
INT=$(curl -sk -b "$JAR" -c "$JAR" -X POST "$BASE/auth/oidc" \
  --data-urlencode "authenticity_token=$FORMTOKEN" --data-urlencode "button=continue" \
  -o /dev/null -w '%{redirect_url}')
[ -n "$INT" ] || { echo "FAIL: no oidc redirect" >&2; exit 2; }
# follow the provider auth URL down to the interaction
INT=$(curl -sk -b "$JAR" -c "$JAR" -o /dev/null -w '%{url_effective}' -L --max-redirs 8 "$INT")
case "$INT" in
  */openid/interaction/*) : ;;
  *) echo "FAIL: no interaction reached: $INT" >&2; exit 3 ;;
esac
UIDPATH=$(printf '%s' "$INT" | grep -o '/openid/interaction/[^?]*')

BODY="{\"username\":\"$U\",\"password\":\"$PW\""
if [ -n "$SEED" ]; then
  TCODE=$(bash "$(dirname "$0")/totp.sh" "$SEED")
  BODY="$BODY,\"totpToken\":\"$TCODE\""
fi
BODY="$BODY}"
LOGIN_RESP=$(curl -sk -b "$JAR" -c "$JAR" -X POST "$IDP$UIDPATH/login" -H 'Content-Type: application/json' -d "$BODY")
unset BODY
case "$LOGIN_RESP" in
  *redirectTo*) : ;;
  *) echo "FAIL: login rejected: $LOGIN_RESP" >&2; exit 5 ;;
esac
RED=$(printf '%s' "$LOGIN_RESP" | sed -n 's/.*"redirectTo":"\([^"]*\)".*/\1/p')

FINAL=$(curl -sk -b "$JAR" -c "$JAR" -o /dev/null -w '%{url_effective}' -L --max-redirs 8 "$RED")
case "$FINAL" in
  */openid/interaction/*)
    CUIDPATH=$(printf '%s' "$FINAL" | grep -o '/openid/interaction/[^?]*')
    CLOC=$(curl -sk -b "$JAR" -c "$JAR" -D - -o /dev/null -X POST "$IDP$CUIDPATH/confirm" -d '' | grep -i '^location:' | head -1 | tr -d '\r' | sed 's/^[Ll]ocation: //')
    [ -n "$CLOC" ] || { echo "FAIL: consent confirm produced no redirect" >&2; exit 6; }
    CLOC=$(printf '%s' "$CLOC" | sed 's|^https//|https://|; s|^http//|http://|')
    case "$CLOC" in http://*|https://*) : ;; /*) CLOC="$IDP$CLOC" ;; *) CLOC="$IDP/$CLOC" ;; esac
    FINAL=$(curl -sk -b "$JAR" -c "$JAR" -o /dev/null -w '%{url_effective}' -L --max-redirs 8 "$CLOC")
    ;;
esac

WHO=$(curl -sk -b "$JAR" "$BASE/session/current.json" | sed -n 's/.*"username":"\([^"]*\)".*/\1/p' | head -1)
if [ -n "$WHO" ]; then
  echo "OK: $WHO logged into discourse (session verified)"
  exit 0
fi
echo "FAIL: no discourse session, landed: $FINAL" >&2
exit 7