#!/usr/bin/env bash
#
# light.sh
#
# Requires:
#   - curl
#   - jq
#   - GNU date (coreutils)
#   - netcat / nc
#
# Run:
#   ./light.sh
#
# Print only sunset Unix timestamp:
#   ./light.sh --print-sunset
#

set -euo pipefail

# --------------------------------------------
# Config
# --------------------------------------------

LAT="37.619024"
LNG="55.751999"

# Use the timezone for both API and 23:00 cutoff
TIMEZONE="Europe/Moscow"

# Configurable IP addresses.
# Add as many as you need.
IP_ADDR=(
    "192.168.1.185"
    # "192.168.1.186"
    # "192.168.1.187"
)

LIGHT_PORT=38899
LIGHT_ID=1

# --------------------------------------------
# Dependency check
# --------------------------------------------

for cmd in curl jq nc date; do
    if ! command -v "$cmd" >/dev/null 2>&1; then
        printf 'Missing dependency: %s\n' "$cmd" >&2
        exit 1
    fi
done

# --------------------------------------------
# Send UDP command to all configured IPs
# --------------------------------------------

send_state() {
    local state="$1"   # true or false

    local json_state
    if [[ "$state" == "true" ]]; then
        json_state="true"
    else
        json_state="false"
    fi

    for ip in "${IP_ADDR[@]}"; do
        printf '{"id":%s,"method":"setState","params":{"state":%s}}\n' \
            "$LIGHT_ID" "$json_state" |
            nc -u -w 1 "$ip" "$LIGHT_PORT" || true
    done
}

# --------------------------------------------
# Get sunset as Unix epoch seconds
# --------------------------------------------

get_sunset_epoch() {
    # Explicit local date for the API request.
    # This avoids issues if the API interprets "today" differently.
    local date_str
    date_str=$(TZ="$TIMEZONE" date +%Y-%m-%d)

    local url
    url="https://api.sunrise-sunset.org/json?lat=${LAT}&lng=${LNG}&date=${date_str}&tzid=${TIMEZONE}&formatted=0"

    local response
    response=$(curl -sL --max-time 10 "$url") || return 1

    if ! jq -e '.status == "OK"' <<< "$response" >/dev/null; then
        return 1
    fi

    local sunset_iso
    sunset_iso=$(jq -r '.results.sunset // ""' <<< "$response")

    if [[ -z "$sunset_iso" ]]; then
        return 1
    fi

    # If the API returns only a time like "18:00:00+03:00",
    # add the local date before conversion.
    if [[ ! "$sunset_iso" =~ ^[0-9]{4} ]]; then
        sunset_iso="${date_str} ${sunset_iso}"
    fi

    # GNU date supports --date / -d
    date -d "$sunset_iso" +%s
}

# --------------------------------------------
# Optional: print only sunset Unix timestamp
# --------------------------------------------

if [[ "${1:-}" == "--print-sunset" ]]; then
    printf '%d\n' "$(get_sunset_epoch)"
    exit 0
fi

# --------------------------------------------
# Main logic
# --------------------------------------------

current_epoch=$(date +%s)

local_date=$(TZ="$TIMEZONE" date +%Y-%m-%d)
cutoff_epoch=$(TZ="$TIMEZONE" date -d "${local_date} 23:00:00" +%s)

if ! sunset_epoch=$(get_sunset_epoch); then
    printf 'ERROR: failed to get sunset from API\n' >&2
    exit 1
fi

printf 'current_epoch=%d\n' "$current_epoch"
printf 'sunset_epoch=%d\n' "$sunset_epoch"
printf 'cutoff_23_00=%d\n' "$cutoff_epoch"

# Turn ON only if:
#   current time is AFTER sunset
#   AND current time is BEFORE 23:00 local time
#
# Otherwise, turn OFF.
if (( current_epoch > sunset_epoch && current_epoch < cutoff_epoch )); then
    send_state true
    printf 'light_state=on reason=after_sunset_and_before_23:00\n'
else
    send_state false
    printf 'light_state=off reason=before_sunset_or_after_23:00\n'
fi