#!/bin/sh

# Low-confidence snapshot helper for yolov5 inference.
# Expected arguments:
#   1 source      RTSP URL or local video file path from yolov5 -s
#   2 camera_id   Camera id from yolov5 -c
#   3 timestamp   Unix timestamp of the detection event
#   4 class_name  Detected class name
#   5 confidence  Detection confidence
#   6 left        Box left
#   7 top         Box top
#   8 right       Box right
#   9 bottom      Box bottom
#
# The script prints status lines to stdout/stderr. The inference program should
# capture those lines and write them into its own detect log.

SOURCE="$1"
CAMERA_ID="$2"
TS="$3"
CLASS_NAME="$4"
CONF="$5"
LEFT="$6"
TOP="$7"
RIGHT="$8"
BOTTOM="$9"

SCRIPT_DIR="$(CDPATH= cd -- "$(dirname -- "$0")" && pwd)"
SNAPSHOT_TIMEOUT="${SNAPSHOT_TIMEOUT:-15}"
LOG_ROOT="${LOG_ROOT:-${SCRIPT_DIR}/.log}"
SNAPSHOT_DAY="$(date -d "@${TS}" "+%Y-%m-%d" 2>/dev/null || date "+%Y-%m-%d")"
SNAPSHOT_ROOT="${SNAPSHOT_ROOT:-${LOG_ROOT}/snapshots/${SNAPSHOT_DAY}}"

now_text() {
    date "+%Y-%m-%d %H:%M:%S"
}

log_info() {
    echo "$(now_text) low_conf_snapshot INFO $*"
}

log_error() {
    echo "$(now_text) low_conf_snapshot ERROR $*" >&2
}

sanitize() {
    echo "$1" | tr -c 'A-Za-z0-9_.-' '_'
}

if [ "$#" -lt 9 ]; then
    log_error "invalid arguments: expected 9, got $#"
    log_error "usage: $0 <source> <camera_id> <timestamp> <class_name> <confidence> <left> <top> <right> <bottom>"
    exit 2
fi

if ! command -v ffmpeg >/dev/null 2>&1; then
    log_error "ffmpeg not found"
    exit 127
fi

CLASS_SAFE="$(sanitize "$CLASS_NAME")"
CONF_SAFE="$(sanitize "$CONF")"
BOX_SAFE="$(sanitize "${LEFT}_${TOP}_${RIGHT}_${BOTTOM}")"
OUT_DIR="${SNAPSHOT_ROOT}"
OUT_FILE="${OUT_DIR}/${TS}_${CAMERA_ID}_${CLASS_SAFE}_${CONF_SAFE}_${BOX_SAFE}.jpg"

if ! mkdir -p "$OUT_DIR"; then
    log_error "failed to create output dir: $OUT_DIR"
    exit 1
fi

log_info "start source=\"$SOURCE\" camera_id=\"$CAMERA_ID\" ts=\"$TS\" class=\"$CLASS_NAME\" conf=\"$CONF\" box=($LEFT $TOP $RIGHT $BOTTOM)"

if command -v timeout >/dev/null 2>&1; then
    TIMEOUT_CMD="timeout ${SNAPSHOT_TIMEOUT}"
else
    TIMEOUT_CMD=""
fi

case "$SOURCE" in
    rtsp://*|RTSP://*)
        # For RTSP streams, capture one live frame from the camera.
        # shellcheck disable=SC2086
        $TIMEOUT_CMD ffmpeg -y -rtsp_transport tcp -i "$SOURCE" -frames:v 1 -q:v 2 "$OUT_FILE" >/tmp/low_conf_snapshot_ffmpeg.log 2>&1
        RET=$?
        ;;
    *)
        # For local mp4/h264 test files, capture the first decodable frame.
        # shellcheck disable=SC2086
        $TIMEOUT_CMD ffmpeg -y -i "$SOURCE" -frames:v 1 -q:v 2 "$OUT_FILE" >/tmp/low_conf_snapshot_ffmpeg.log 2>&1
        RET=$?
        ;;
esac

if [ "$RET" -ne 0 ]; then
    log_error "ffmpeg failed ret=$RET output=\"$OUT_FILE\""
    if [ -f /tmp/low_conf_snapshot_ffmpeg.log ]; then
        sed 's/^/ffmpeg: /' /tmp/low_conf_snapshot_ffmpeg.log >&2
    fi
    rm -f "$OUT_FILE"
    exit "$RET"
fi

if [ ! -s "$OUT_FILE" ]; then
    log_error "snapshot file is empty or missing: $OUT_FILE"
    exit 1
fi

log_info "saved output=\"$OUT_FILE\""
exit 0