/*eslint complexity: ["error", 13]*/
import {
    Node,
    NodeMessage,
    NodeStatus,
    NodeStatusFill,
} from 'node-red'
import { util } from '@node-red/util'
import { ISmallTimerProperties, Rule } from '../nodes/common'
import {
    SmallTimerChangeMessage,
    ISmallTimerMessage,
    Trigger,
    State,
} from './interfaces'
import { TimeCalc } from './time-calculation'
import { Timer } from './timer'

type NodeFunctions = Node

type Position = {
    latitude: number,
    longitude: number,
}

const pad = (n: number) => n < 10 ? `0${n.toFixed(0)}` : `${n.toFixed(0)}`

const SecondsTick = 1000

export class SmallTimerRunner {

    private readonly startupTock: ReturnType<typeof setTimeout> | undefined = undefined

    // Timing variables
    private tickTimer: ReturnType<typeof setInterval> | undefined = undefined
    private tickTimerInterval: number = 0
    private lastPublish: number = 0
    private override: State = 'auto'
    private currentState = false

    private readonly topic: string
    private readonly onMsg: string
    private readonly offMsg: string
    private readonly onMsgType: string
    private readonly offMsgType: string
    private readonly rules: Rule[]
    private readonly repeat: boolean
    private readonly repeatInterval: number
    private readonly onTimeout: number
    private readonly offTimeout: number

    private readonly timeCalc: TimeCalc
    private readonly debugMode: boolean

    private readonly timer = new Timer()
    private readonly sendEmptyPayload: boolean

    // Default to 20 seconds between ticks (update of state / node)
    private readonly defaultTickTimer = SecondsTick * 20

    constructor(
        position: Position | undefined,
        configuration: ISmallTimerProperties,
        private readonly node: NodeFunctions,
    ) {
        this.timeCalc = new TimeCalc(
            position ? Number(position.latitude) : undefined,
            position ? Number(position.longitude) : undefined,
            configuration.wrapMidnight,
            Number(configuration.startTime),
            Number(configuration.endTime),
            Number(configuration.startOffset),
            Number(configuration.endOffset),
            Number(configuration.minimumOnTime),
        )

        this.topic = configuration.topic
        this.onMsg = configuration.onMsg
        this.offMsg = configuration.offMsg
        this.onMsgType = configuration.onMsgType
        this.offMsgType = configuration.offMsgType
        this.rules = configuration.rules
        this.repeat = configuration.repeat

        this.repeatInterval = this.repeat
            ? Number(configuration.repeatInterval || 60)
            : 60

        // default tick timer is 3 times as frequent as repeat timer, but never below 1 second
        this.defaultTickTimer = this.repeatInterval * SecondsTick / 3
        if (this.defaultTickTimer < SecondsTick) {
            this.defaultTickTimer = SecondsTick
        }

        this.debugMode = configuration.debugEnable

        this.onTimeout = Number(configuration.onTimeout)
        this.offTimeout = Number(configuration.offTimeout)
        this.sendEmptyPayload = configuration.sendEmptyPayload ?? true

        if (configuration.injectOnStartup) {
            this.startupTock = setTimeout(this.forceSend.bind(this), 2 * SecondsTick)
        } else {
            this.calcState()
            this.updateNodeStatus()
        }
        this.startTickTimer(this.defaultTickTimer)
    }

    /**
     * Calculates the current state of the output (combines override and auto state)
     * @returns boolean
     */
    private getCurrentState(): boolean {
        return this.override === 'auto'
            ? this.currentState
            : (this.override === 'tempOn')
    }

    private generateDebug(): NodeMessage {
        return {
            ...this.timeCalc.debug(),
            override: this.override,
            weekNumber: this.getWeekNumber(),
            topic: 'debug',
        } as NodeMessage // we cheat a bit to escape type checking in typescript
    }

    private generateMsg(trigger: Trigger): SmallTimerChangeMessage {
        const status = this.getCurrentState()

        const payload = status
            ? util.evaluateNodeProperty(this.onMsg, this.onMsgType, this.node, {})
            : util.evaluateNodeProperty(this.offMsg, this.offMsgType, this.node, {})

        return {
            state: this.override,
            stamp: Date.now(),
            autoState: this.override === 'auto',
            duration: 0,
            temporaryManual: this.override !== 'auto',
            timeout: this.timer.timeLeft(),
            payload: payload,
            topic: this.topic,
            trigger,
        }
    }

    private publishState(trigger: Trigger): void {
        const status = this.generateMsg(trigger)
        const shouldSendStatus = this.sendEmptyPayload || status.payload !== ''

        if (this.debugMode) {
            this.node.send([
                shouldSendStatus ? status : null,
                this.generateDebug(),
            ])
            return
        }

        if (shouldSendStatus) {
            this.node.send(status)
        }
    }

    private getWeekNumber(): number {
        // Idea from https://weeknumber.com/how-to/javascript
        const currentDate = new Date()
        currentDate.setHours(0, 0, 0, 0)
        // Thursday in current week decides the year.
        currentDate.setDate(currentDate.getDate() + 3 - (currentDate.getDay() + 6) % 7)
        // January 4 is always in week 1.
        const week1 = new Date(currentDate.getFullYear(), 0, 4)
        // Adjust to Thursday in week 1 and count number of weeks from date to week1.
        return 1 + Math.round(((currentDate.getTime() - week1.getTime()) / 86400000
                              - 3 + (week1.getDay() + 6) % 7) / 7)
    }

    private isDayOk(date = new Date()): boolean {
        const month = date.getMonth() + 1
        const week = this.getWeekNumber()
        const dayOfMonth = date.getDate()
        const dayOfWeek = date.getDay()

        const oddOrEvenWeek = Math.floor(week / 2) === week / 2
            ? 200
            : 201

        const validMonths = [0, month, week + 100, oddOrEvenWeek]
        const validDays = [0, dayOfMonth, dayOfWeek + 100]

        let isOk = false

        this.rules.forEach((item: Rule) => {
            const ruleMonth = Number(item.month)
            const ruleDay = Number(item.day)

            if (validMonths.includes(ruleMonth)
                && validDays.includes(ruleDay)) {
                isOk = item.type === 'include'
            }
        })
        return isOk
    }

    /**
     * Calculates, and set, new state. If a change from previous state is detected, the method returns true,
     * otherwise it returns false
     */
    private calcState(): boolean {
        const date = new Date()
        const newState = this.timeCalc.getOnState(date)

        // Check if the new state is different, because then we need to send a change event
        if ((this.isDayOk(date) || this.currentState) && (newState !== this.currentState)) {
            this.currentState = newState
            return true
        }

        return false
    }

    private shouldRepeatPublish(): boolean {
        const seconds = Date.now() / SecondsTick
        if (this.repeat && (seconds - this.lastPublish >= this.repeatInterval)) {
            this.lastPublish = seconds
            return true
        }
        return false
    }

    /**
     * Handle timer updates
     */
    private timerEvent(): void {
        const change = this.calcState()

        const nextChange = this.updateNodeStatus()

        if (nextChange < 60) {
            this.startTickTimer(SecondsTick)
        } else {
            this.startTickTimer(this.defaultTickTimer)
        }

        if (change || this.shouldRepeatPublish()) {
            this.publishState('timer')
        }
    }

    private forceSend(trigger: Trigger = 'timer'): void {
        this.calcState()
        this.updateNodeStatus()
        this.publishState(trigger)
    }

    /**
     * Convert a time in minutes to hours / minutes string
     * @param time
     * @returns
     */
    private getHumanTime(time: number): string {
        const hour = Math.floor(time / 60)
        const minutes = time % 60
        // Seconds are fractions, so we need to "up-cycle" them
        const seconds = Math.floor((time - Math.floor(time)) * 60)

        const str: string[] = []

        if (hour) {
            str.push(`${pad(hour)}hrs`)
        }
        if (minutes >= 1 || hour) {
            str.push(`${pad(minutes)}mins`)
        } else {
            str.push(`${pad(seconds)}secs`)
        }
        return str.join(' ')
    }

    /**
     * Updates the node status
     */
    private updateNodeStatus() {
        let fill: NodeStatusFill = 'yellow'
        const text: string[] = []

        const activeToday = this.timeCalc.operationToday() === 'normal' && (this.isDayOk() || this.currentState)

        if (!activeToday) {
            text.push('No action today')
        }

        switch (this.timeCalc.operationToday()) {
            case 'noMidnightWrap':
                text.push('off time is before on time')
                break
            case 'minimumOnTimeNotMet':
                text.push('minimum on time not met')
        }

        let nextTimeoutOrAuto = Number.MAX_SAFE_INTEGER

        if (activeToday || this.override !== 'auto') {
            // default off state
            fill = 'red'
            let state = 'OFF'
            let nextAutoChange = this.timeCalc.getTimeToNextStartEvent()

            if (this.getCurrentState()) {
                // Signal that we have turned ON
                fill = 'green'
                state = 'ON'
                nextAutoChange = this.timeCalc.getTimeToNextEndEvent()
            }
            const timeout = this.timer.timeLeft()
            nextTimeoutOrAuto = timeout && (timeout < nextAutoChange)
                ? timeout
                : nextAutoChange

            if (this.override !== 'auto') {
                text.length = 0 // Reset array
                text.push(`Temporary ${state} for ${this.getHumanTime(nextTimeoutOrAuto)}`)
            }
            else {
                text.push(`${state} for ${this.getHumanTime(nextTimeoutOrAuto)}`)
            }
        }

        const status: NodeStatus = {
            fill,
            shape: this.override !== 'auto' ? 'ring' : 'dot',
            text: text.join(' - '),
        }

        this.node.status(status)

        return nextTimeoutOrAuto
    }

    private doOverride(override: State, timeout?: number): void {
        this.override = override
        if (override === 'auto') {
            this.timer.stop()
            return
        }

        // requested temporary state is the same as what would be the current auto state
        // So let's just set it to auto
        if ((override === 'tempOn') === this.currentState) {
            this.override = 'auto'
            this.timer.stop()
            return
        }

        const timerTimeout = override === 'tempOn'
            ? (timeout ?? this.onTimeout)
            : (timeout ?? this.offTimeout)

        this.timer.start(timerTimeout, () => {
            this.override = 'auto'
            this.forceSend()
        })
    }

    /**
     * Handle messages as they are received
     * @param incomingMsg
     */
    // eslint-disable-next-line complexity
    public onMessage(
        incomingMsg: Readonly<ISmallTimerMessage>,
    ): void {
        if (incomingMsg.reset !== undefined) {
            this.doOverride('auto')
            this.forceSend('input')
            return
        }

        const payload = typeof incomingMsg.payload === 'string'
            ? incomingMsg.payload.toLocaleLowerCase()
            : incomingMsg.payload

        const timeout = incomingMsg.timeout !== undefined ? Number(incomingMsg.timeout) : undefined
        if (timeout !== undefined && isNaN(timeout)) {
            throw new Error(`Timeout value "${incomingMsg.timeout}" can not be converted to a number`)
        }

        switch (payload) {
            case 0:
            case '0':
            case 'off':
            case 'false':
            case false:
                this.doOverride('tempOff', timeout)
                break
            case 1:
            case '1':
            case 'on':
            case 'true':
            case true:
                this.doOverride('tempOn', timeout)
                break
            case 'toggle':
                this.doOverride(
                    this.getCurrentState()
                        ? 'tempOff'
                        : 'tempOn',
                    timeout,
                )
                break
            case 'auto':
            case 'default':
                this.doOverride('auto')
                break
            case 'sync':
                break
            default:
                throw new Error(`Did not understand the command '${incomingMsg.payload}' supplied in payload`)
        }
        this.forceSend('input')
    }

    /**
     * Cleanup before closing down (ie. remove timers)
     */
    /* istanbul ignore next */
    public cleanup(): void {
        if (this.startupTock) {
            clearTimeout(this.startupTock)
        }
        this.stopTickTimer()
    }

    /* istanbul ignore next */
    private stopTickTimer(): void {
        if (this.tickTimer) {
            clearInterval(this.tickTimer)
            this.tickTimer = undefined
        }
    }

    private startTickTimer(newInterval: number): void {
        if (this.tickTimer && (newInterval === this.tickTimerInterval)) {
            // No need in (re) starting the tick timer, if it running with desired interval already
            return
        }

        this.stopTickTimer()
        this.tickTimerInterval = newInterval
        this.tickTimer = setInterval(this.timerEvent.bind(this), newInterval)
    }
}