#!/usr/bin/env bash
# Holt alle Zammad-Articles der letzten X Tage, gefiltert nach type_id und created_by_id.
#
# Aufruf:  ZAMMAD_TOKEN=xxx ./zammad_articles.sh [TAGE] [CREATED_BY_ID] [TYPE_ID]
# Beispiel: ZAMMAD_TOKEN=xxx ./zammad_articles.sh 2 1764 1 > mails.json
#
# Voraussetzungen: curl, jq, API-Token mit Admin-Rechten (für /ticket_articles)

set -euo pipefail

BASE_URL="${ZAMMAD_URL:-https://aikava.zammad.com}"
TOKEN="${ZAMMAD_TOKEN:?Bitte ZAMMAD_TOKEN setzen}"
DAYS="${1:-2}"
CREATED_BY="${2:-1764}"
TYPE_ID="${3:-1}"
PER_PAGE=1000
MAX_PAGE=1000000   # Schutz gegen Endlosschleifen

# Call-Zähler über eine Temp-Datei, da fetch_page oft in $(...) läuft
CALLS_FILE=$(mktemp)
trap 'rm -f "$CALLS_FILE"' EXIT
calls() { wc -l < "$CALLS_FILE" | tr -d ' '; }

# Stichtag in UTC (GNU date oder BSD/macOS date)
# CALENDAR=1: ab lokaler Mitternacht vor (TAGE-1) Tagen, also TAGE=2 -> gestern 00:00 bis jetzt
# sonst:      rollierend, jetzt minus TAGE*24h
if date -u -d "now" >/dev/null 2>&1; then
  if [ "${CALENDAR:-0}" = "1" ]; then
    TS=$(date -d "$((DAYS - 1)) days ago 00:00" +%s)
  else
    TS=$(date -d "${DAYS} days ago" +%s)
  fi
  CUTOFF=$(date -u -d "@${TS}" +%Y-%m-%dT%H:%M:%S)
else
  if [ "${CALENDAR:-0}" = "1" ]; then
    TS=$(date -v-"$((DAYS - 1))"d -v0H -v0M -v0S +%s)
  else
    TS=$(date -v-"${DAYS}"d +%s)
  fi
  CUTOFF=$(date -u -r "${TS}" +%Y-%m-%dT%H:%M:%S)
fi

log() { echo "$*" >&2; }

fetch_page() {
  echo "$1" >> "$CALLS_FILE"
  curl -sf -H "Authorization: Token token=${TOKEN}" \
    "${BASE_URL}/api/v1/ticket_articles?page=$1&per_page=${PER_PAGE}"
}

page_len() { fetch_page "$1" | jq 'length'; }

log "Stichtag: ${CUTOFF}Z | created_by_id=${CREATED_BY} | type_id=${TYPE_ID}"

# 1) Letzte nicht-leere Seite per Binärsuche finden
if [ "$(page_len 1)" -eq 0 ]; then
  log "Keine Articles gefunden. (API-Calls: $(calls))"
  echo "[]"
  exit 0
fi

lo=1; hi=2
while [ "$hi" -le "$MAX_PAGE" ] && [ "$(page_len "$hi")" -gt 0 ]; do
  lo=$hi; hi=$((hi * 2))
done
while [ $((hi - lo)) -gt 1 ]; do
  mid=$(( (lo + hi) / 2 ))
  if [ "$(page_len "$mid")" -gt 0 ]; then lo=$mid; else hi=$mid; fi
done
SEARCH_CALLS=$(calls)
log "Letzte Seite: ${lo} (Binärsuche: ${SEARCH_CALLS} Calls)"

# 2) Rückwärts lesen bis zum Stichtag und filtern
results="[]"
p=$lo
while [ "$p" -ge 1 ]; do
  batch=$(fetch_page "$p")
  matches=$(jq --arg c "$CUTOFF" --argjson u "$CREATED_BY" --argjson t "$TYPE_ID" \
    '[.[] | select(.created_at >= $c and .type_id == $t and .created_by_id == $u)]' <<<"$batch")
  results=$(jq -s 'add' <(echo "$results") <(echo "$matches"))

  oldest=$(jq -r '.[0].created_at // empty' <<<"$batch")
  log "Seite ${p}: $(jq 'length' <<<"$matches") Treffer (ältester Article: ${oldest})"
  [[ -z "$oldest" || "$oldest" < "$CUTOFF" ]] && break
  p=$((p - 1))
done

TOTAL_CALLS=$(calls)
log "Gesamt: $(jq 'length' <<<"$results") Articles"
log "API-Calls: ${TOTAL_CALLS} (Binärsuche: ${SEARCH_CALLS}, Rückwärts lesen: $((TOTAL_CALLS - SEARCH_CALLS)))"
jq 'sort_by(.id)' <<<"$results"