#!/usr/bin/env bash
# Simulate RTSP cameras by looping mp4 files through MediaMTX + ffmpeg.
#
# Usage: ./scripts/sim_cameras.sh
#
# Reads camera ids from config/vigilar.toml, expects videos/<id>.mp4 for each,
# starts MediaMTX on 127.0.0.1:8554, spawns one ffmpeg per camera, and writes
# config/vigilar.sim.toml with rtsp_urls rewritten to the local endpoints.
# Ctrl-C tears everything down.
set -euo pipefail

REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
REAL_CONFIG="${REPO_ROOT}/config/vigilar.toml"
SIM_CONFIG="${REPO_ROOT}/config/vigilar.sim.toml"
VIDEOS_DIR="${REPO_ROOT}/videos"
SIM_DIR="${REPO_ROOT}/.sim"
LOG_DIR="${SIM_DIR}/logs"
MEDIAMTX_BIN="${SIM_DIR}/mediamtx"
RTSP_HOST="127.0.0.1"
RTSP_PORT="8554"

MEDIAMTX_PID=""
FFMPEG_PIDS=()

cleanup() {
  local pid
  for pid in "${FFMPEG_PIDS[@]}"; do
    if [[ -n "${pid}" ]] && kill -0 "${pid}" 2>/dev/null; then
      kill "${pid}" 2>/dev/null || true
    fi
  done
  if [[ -n "${MEDIAMTX_PID}" ]] && kill -0 "${MEDIAMTX_PID}" 2>/dev/null; then
    kill "${MEDIAMTX_PID}" 2>/dev/null || true
  fi
  sleep 0.3
  for pid in "${FFMPEG_PIDS[@]}" "${MEDIAMTX_PID}"; do
    if [[ -n "${pid}" ]] && kill -0 "${pid}" 2>/dev/null; then
      kill -9 "${pid}" 2>/dev/null || true
    fi
  done
  rm -rf "${SIM_DIR:?}/logs"
}
trap cleanup EXIT INT TERM

die() { echo "error: $*" >&2; exit 1; }

# --- prereq checks ---------------------------------------------------------

command -v ffmpeg >/dev/null 2>&1 || die "ffmpeg not found on PATH. Install it and retry."
[[ -x "${MEDIAMTX_BIN}" ]] || die "MediaMTX binary not found at ${MEDIAMTX_BIN}. Run: scripts/download_mediamtx.sh"
[[ -f "${REAL_CONFIG}" ]] || die "config file not found: ${REAL_CONFIG}"
[[ -d "${VIDEOS_DIR}" ]] || die "videos directory not found: ${VIDEOS_DIR} (create it and drop <camera_id>.mp4 files inside)"

# --- parse camera ids from vigilar.toml ------------------------------------
# Grab every `id = "..."` line that sits inside a [[cameras]] block.

mapfile -t CAMERA_IDS < <(awk '
  /^\[\[cameras\]\]/ { in_cams = 1; next }
  /^\[/ && !/^\[\[cameras\]\]/ { in_cams = 0 }
  in_cams && /^[[:space:]]*id[[:space:]]*=/ {
    match($0, /"([^"]+)"/, m)
    if (m[1] != "") print m[1]
  }
' "${REAL_CONFIG}")

[[ ${#CAMERA_IDS[@]} -gt 0 ]] || die "no [[cameras]] blocks with an id field found in ${REAL_CONFIG}"

# --- verify every camera has a matching video -----------------------------

MISSING=()
for id in "${CAMERA_IDS[@]}"; do
  [[ -f "${VIDEOS_DIR}/${id}.mp4" ]] || MISSING+=("${VIDEOS_DIR}/${id}.mp4")
done
if [[ ${#MISSING[@]} -gt 0 ]]; then
  echo "error: missing video files for cameras:" >&2
  for f in "${MISSING[@]}"; do echo "  - ${f}" >&2; done
  exit 1
fi

# --- start MediaMTX --------------------------------------------------------

mkdir -p "${LOG_DIR}"
echo "Starting MediaMTX on ${RTSP_HOST}:${RTSP_PORT}..."
"${MEDIAMTX_BIN}" >"${LOG_DIR}/mediamtx.log" 2>&1 &
MEDIAMTX_PID=$!

for _ in $(seq 1 30); do
  if (exec 3<>"/dev/tcp/${RTSP_HOST}/${RTSP_PORT}") 2>/dev/null; then
    exec 3<&- 3>&-
    break
  fi
  sleep 0.1
done
if ! (exec 3<>"/dev/tcp/${RTSP_HOST}/${RTSP_PORT}") 2>/dev/null; then
  echo "MediaMTX failed to bind ${RTSP_HOST}:${RTSP_PORT}. Log tail:" >&2
  tail -n 20 "${LOG_DIR}/mediamtx.log" >&2 || true
  exit 1
fi
exec 3<&- 3>&- 2>/dev/null || true

# --- spawn one ffmpeg per camera -------------------------------------------

for id in "${CAMERA_IDS[@]}"; do
  video="${VIDEOS_DIR}/${id}.mp4"
  url="rtsp://${RTSP_HOST}:${RTSP_PORT}/${id}"
  echo "Publishing ${video} -> ${url}"
  ffmpeg -nostdin -loglevel warning \
    -stream_loop -1 -re -i "${video}" \
    -c copy -f rtsp "${url}" \
    >"${LOG_DIR}/${id}.log" 2>&1 &
  FFMPEG_PIDS+=($!)
done

# --- write the sim config --------------------------------------------------
# Copy vigilar.toml, rewrite each `rtsp_url = "..."` line inside a
# [[cameras]] block to point at the local MediaMTX endpoint for that camera.
# Relies on `id` preceding `rtsp_url` within each block (the standing
# convention in config/vigilar.toml).

awk -v host="${RTSP_HOST}" -v port="${RTSP_PORT}" '
  /^\[\[cameras\]\]/ { in_cams = 1; current_id = ""; print; next }
  /^\[/ && !/^\[\[cameras\]\]/ { in_cams = 0; print; next }
  in_cams && /^[[:space:]]*id[[:space:]]*=/ {
    match($0, /"([^"]+)"/, m)
    current_id = m[1]
    print
    next
  }
  in_cams && /^[[:space:]]*rtsp_url[[:space:]]*=/ && current_id != "" {
    printf "rtsp_url = \"rtsp://%s:%s/%s\"\n", host, port, current_id
    next
  }
  { print }
' "${REAL_CONFIG}" > "${SIM_CONFIG}"

# --- summary ---------------------------------------------------------------

echo
echo "Simulator running. ${#CAMERA_IDS[@]} stream(s):"
for id in "${CAMERA_IDS[@]}"; do
  echo "  rtsp://${RTSP_HOST}:${RTSP_PORT}/${id}"
done
echo
echo "Sim config written to: ${SIM_CONFIG}"
echo "Start Vigilar in another terminal:"
echo "  vigilar start --config ${SIM_CONFIG#"${REPO_ROOT}"/}"
echo
echo "Press Ctrl-C to stop."

wait