#!/bin/bash

# Variables
BAT_CHRG_HOSTNAME="obkbat"
BAT_CHRG_READ="http://obkbat.local/index"

INV_PWR_HOSTNAME="obkinv"
INV_PWR_READ="http://obkinv.local/index"

BMS_BAT_HOSTNAME="hackberrypi"
BMS_BAT_READ="http://hackberrypi.local:8000/status"

retry() {
    local max_attempts="$1" delay="$2"
    shift 2
    local attempt=1

    until "$@"; do
        if (( attempt >= max_attempts )); then
            date +"%d.%m.%Y %H:%M:%S Error: '$*' finally failed"
            return 1
        fi
        sleep "$delay"
        ((attempt++))
    done
}

get_data() {
    # Get Data
    BAT_CHRG_DATA=$(retry 3 15 curl -sf --max-time 5 "$BAT_CHRG_READ")
    INV_PWR_DATA=$(retry 3 15 curl -sf --max-time 5 "$INV_PWR_READ")
    BMS_BAT_DATA=$(retry 3 15 curl -sf --max-time 30 "$BMS_BAT_READ")
    
    # Error Handling
    if [[ -z "$BAT_CHRG_DATA" || -z "$INV_PWR_DATA" ]]; then
        date +"%d.%m.%Y %H:%M:%S Error [get_data]: No connection to OBK"
        bms_switch "off" "$BMS_BAT_HOSTNAME"
        exit 1
    fi
    
    if [[ -z "$BMS_BAT_DATA" ]]; then
        date +"%d.%m.%Y %H:%M:%S Error [get_data]: No connection to Battery"
        obk_switch "off" "$INV_PWR_HOSTNAME"
        obk_switch "off" "$BAT_CHRG_HOSTNAME"
        exit 1
    fi
}

get_state() {
    # Get current OpenBK states
    BAT_CHRG_SWITCH_STATE=$(echo "$BAT_CHRG_DATA" | grep -Po "<td class='(off|on)'>\K[^<]+")
    INV_PWR_SWITCH_STATE=$(echo "$INV_PWR_DATA" | grep -Po "<td class='(off|on)'>\K[^<]+")
    
    # Get BMS states
    BMS_DISCHARGE=$(echo "$BMS_BAT_DATA" | jq -r '.dischrg_mosfet')
    BMS_CHARGE=$(echo "$BMS_BAT_DATA" | jq -r '.chrg_mosfet')

    if [[ "$BMS_DISCHARGE" == "true" || "$BMS_CHARGE" == "true" ]]; then
        BMS_OUTPUT_STATE="on"
    else 
        BMS_OUTPUT_STATE="off"
    fi

    # Error Handling
    if [[ "$BAT_CHRG_SWITCH_STATE" != @(ON|OFF) || \
          "$INV_PWR_SWITCH_STATE" != @(ON|OFF) || \
          "$BMS_DISCHARGE" != @(true|false) || \
          "$BMS_CHARGE" != @(true|false) ]]; then

        echo "$BMS_BAT_DATA"
        date +"%d.%m.%Y %H:%M:%S Error [get_state]: Failed to parse one or more switch states." >&2
        obk_switch "off" "$INV_PWR_HOSTNAME"
        obk_switch "off" "$BAT_CHRG_HOSTNAME"
        bms_switch "off" "$BMS_BAT_HOSTNAME"
        exit 1
    fi

    # Logic - Get current State
    COMBINATION="${BAT_CHRG_SWITCH_STATE,,},${INV_PWR_SWITCH_STATE,,},${BMS_OUTPUT_STATE}"
    
    case "$COMBINATION" in
        "off,off,off") SYSTEM_STATE="OFF" ;;
        "off,off,on")  SYSTEM_STATE="POWER" ;;
        "on,off,on")   SYSTEM_STATE="CHARGING" ;;
        "off,on,on")   SYSTEM_STATE="DISCHARGING" ;;
        *)             SYSTEM_STATE="UNKNOWN" ;;
    esac    

    date +"%d.%m.%Y %H:%M:%S $SYSTEM_STATE"
}

obk_switch() {
    local SWITCH="$1"
    local HOSTNAME="$2"

    if [[ "$SWITCH" != @(on|off) ]]; then
        date +"%d.%m.%Y %H:%M:%S Error [bms]: Unsupported value"
        return 1
    elif [[ "$SWITCH" == "on" ]]; then
        response=$(retry 3 15 curl -sf "http://${HOSTNAME}.local/cm?cmnd=POWER%20ON" --max-time 5 | jq -r '.POWER')
    else
        response=$(retry 3 15 curl -sf "http://${HOSTNAME}.local/cm?cmnd=POWER%20OFF" --max-time 5 | jq -r '.POWER')
    fi

    if [[ "$response" != @(ON|OFF) ]]; then
        date +"%d.%m.%Y %H:%M:%S Error [obk]: Switch not successful"
        bms_switch "off" "$BMS_BAT_HOSTNAME"
        return 1
    fi 
}

bms_switch() {
    local SWITCH="$1"
    local HOSTNAME="$2"

    if [[ "$SWITCH" != @(on|off) ]]; then
        date +"%d.%m.%Y %H:%M:%S Error [bms]: Unsupported value"
        return 1
    elif [[ "$SWITCH" == "on" ]]; then
        response=$(retry 3 15 curl -sf -X 'POST' \
                      "http://${HOSTNAME}.local:8000/discharge_a_charge?on=true" \
                      -H 'accept: application/json' \
                      -d '' --max-time 20 | jq -r '.discharging')
    else
        response=$(retry 3 15 curl -sf -X 'POST' \
                      "http://${HOSTNAME}.local:8000/discharge_a_charge?on=false" \
                      -H 'accept: application/json' \
                      -d '' --max-time 20 | jq -r '.discharging')
    fi

    if [[ "$response" != @(true|false) ]]; then
        date +"%d.%m.%Y %H:%M:%S Error [bms]: Switch not successful"
        obk_switch "off" "$INV_PWR_HOSTNAME"
        obk_switch "off" "$BAT_CHRG_HOSTNAME"
        return 1
    fi 

}

set_state() {
    local TARGET_STATE="$1"

    # Check if the state would change
    if [[ "$TARGET_STATE" == "$SYSTEM_STATE" ]]; then
        return 0
    fi

    # Set inital state
    if [[ "$SYSTEM_STATE" != "OFF" ]]; then
         bms_switch "off" "$BMS_BAT_HOSTNAME" || return 1
         obk_switch "off" "$INV_PWR_HOSTNAME" || return 1
         obk_switch "off" "$BAT_CHRG_HOSTNAME" || return 1
    fi

    # Logic - Set target State
    case "$TARGET_STATE" in
        "OFF")
            ;;
        "POWER")
            bms_switch "on" "$BMS_BAT_HOSTNAME" || return 1
            ;;
        "CHARGING")
            obk_switch "on" "$BAT_CHRG_HOSTNAME" || return 1
            bms_switch "on" "$BMS_BAT_HOSTNAME" || return 1
            ;;
        "DISCHARGING")
            obk_switch "on" "$INV_PWR_HOSTNAME" || return 1
            bms_switch "on" "$BMS_BAT_HOSTNAME" || return 1
            ;;
        *)
            date +"%d.%m.%Y %H:%M:%S Error [set_state]: Unknown state '$TARGET_STATE'" 
            return 1
            ;;
     esac

     # Update the Batterie state for the db
     get_data

     date +"%d.%m.%Y %H:%M:%S $TARGET_STATE"
}

main() {
    # Threshoulds
    BATTERY_LOW="20"
    SWITCH_TO_DISCHARGING="100"
    SWITCH_TO_ABSOLUTE="4800"
    CHARGE_ON_ABSOLUTE="2000"
    CHARGE_OFF_ABSOLUTE="1500"
    
    # Data
    FORECAST_POWER=$(cat /var/www/html/control)
    BATTERY_LEVEL=$(echo "$BMS_BAT_DATA" | jq -r '.battery_level')
    BATTERY_POWER=$(echo "$BMS_BAT_DATA" | jq -r '.power | round')
    BATTERY_CHARGING=$(echo "$BMS_BAT_DATA" | jq -r '.battery_charging')
    SOLAR_POWER=$(mariadb photovoltaik --password=XXX -N -e "
      SELECT ROUND(
        IFNULL((SELECT AVG(power) FROM inverter1 WHERE timestamp >= NOW() - INTERVAL 15 MINUTE), 0) +
        IFNULL((SELECT AVG(power) FROM inverter2 WHERE timestamp >= NOW() - INTERVAL 15 MINUTE), 0) +
        IFNULL((SELECT AVG(power) FROM inverter3 WHERE timestamp >= NOW() - INTERVAL 15 MINUTE), 0) +
        IFNULL((SELECT AVG(power) FROM inverter4 WHERE timestamp >= NOW() - INTERVAL 15 MINUTE), 0) +
        IFNULL((SELECT AVG(power) FROM inverter5 WHERE timestamp >= NOW() - INTERVAL 15 MINUTE), 0)
      , 0);
    ")

    
    # Error Handling
    if [[ ! "$SOLAR_POWER" =~ ^[0-9]+$ ]]; then
        date +"%d.%m.%Y %H:%M:%S Error [power_avg]: not a valid integer"
        set_state "OFF"
        return 1
    fi
    if [[ ! "$FORECAST_POWER" =~ ^[0-9]+$ ]]; then
        date +"%d.%m.%Y %H:%M:%S Error [forecast_power]: not a valid integer"
        set_state "OFF"
        return 1
    fi
    if [[ ! "$BATTERY_LEVEL" =~ ^[0-9]+$ ]]; then
        date +"%d.%m.%Y %H:%M:%S Error [battery_level]: not a valid integer"
        set_state "OFF"
        return 1
    fi
    if [[ "$BATTERY_CHARGING" != "true" && "$BATTERY_CHARGING" != "false" ]]; then
        echo "$(date +"%d.%m.%Y %H:%M:%S") Error [battery_charging]: not a valid boolean"
        set_state "OFF"
        return 1
    fi

    # Discharging
    if (( SOLAR_POWER <= SWITCH_TO_DISCHARGING )); then
        if (( BATTERY_LEVEL >= BATTERY_LOW )); then
            set_state "DISCHARGING"
        else
            set_state "OFF"
        fi
    # Charging
    elif (( FORECAST_POWER <= SWITCH_TO_ABSOLUTE )); then
        if (( SOLAR_POWER >= CHARGE_ON_ABSOLUTE )); then
            set_state "CHARGING"
        elif (( SOLAR_POWER < CHARGE_OFF_ABSOLUTE )); then
            set_state "OFF"
        fi
    else
        if (( SOLAR_POWER >= FORECAST_POWER )); then
            set_state "CHARGING"
        elif (( SOLAR_POWER < CHARGE_OFF_ABSOLUTE )); then
            set_state "OFF"
        fi
    fi

    # Refresh BMS data
    BATTERY_LEVEL=$(echo "$BMS_BAT_DATA" | jq -r '.battery_level')
    BATTERY_POWER=$(echo "$BMS_BAT_DATA" | jq -r '.power | round')
    BATTERY_CHARGING=$(echo "$BMS_BAT_DATA" | jq -r '.battery_charging')

    # Redis - Update JSON 
    local key="metrics"
 
    # Initialize default key structure ONLY if it doesn't exist yet
    redis-cli JSON.SET "$key" $ '{"solar":{},"water":{},"batterie":{"level":0,"power":0,"charging":false}}' NX >/dev/null

    # Set Timestamp
    redis-cli SET metrics:last_updated $(date +%s) >/dev/null
 
    redis-cli JSON.MERGE "$key" $ "$(cat <<EOF
{
  "batterie": {
    "level": ${BATTERY_LEVEL:-0},
    "power": ${BATTERY_POWER:-0},
    "charging": ${BATTERY_CHARGING:-false}
  }
}
EOF
)" >/dev/null

}

get_data
get_state
main