import { reactive } from "vue"
import { Track } from "./track"
import { Tick } from './ticks'
import { error } from "./error"

enum State {
    Unfetched,
    Fetching,
    Fetched,
}

function dateQuery(date: Date): URLSearchParams {
    let query = new URLSearchParams()
    query.set("year", date.getUTCFullYear().toString())
    query.set("month", (date.getUTCMonth() + 1).toString())
    // good thing I still had this ^^^^^^^^^^^^^^ in mind when I wrote this 😬
    query.set("day", date.getUTCDate().toString())
    return query
}

interface LoggedInUser {
    name: string
}

class AppState {
    tracks: Array<Track>
    state: State
    user?: LoggedInUser

    constructor() {
        this.tracks = new Array<Track>
        this.state = State.Unfetched
    }
    streamUpdatesFromServer() {
        const source = new EventSource("/api/v1/updates")
        source.addEventListener("open", () => console.debug("opened event source"))
        source.addEventListener('message', event => console.log(event))
        source.addEventListener('TickAdded', event => {
            const tick: Tick = Tick.fromJSON(JSON.parse(event.data))
            const tracks = this.tracks.map(track => {
                if (track.id === tick.track_id) {
                    const ticks = track.ticks ?? []
                    ticks.push(tick)
                    track.ticks = ticks
                }
                return track
            })
            this.tracks = tracks
        })
        source.addEventListener('TrackAdded', ({ data }) => {
            const track: Track = Track.fromJSON(JSON.parse(data))
            this.tracks = [track, ...this.tracks]
        })
        source.addEventListener('TickDropped', event => {
            const tick: Tick = Tick.fromJSON(JSON.parse(event.data))
            const tracks = this.tracks.map(track => {
                if (track.id === tick.track_id) {
                    track.ticks = track.ticks?.filter($tick => $tick.id !== tick.id)
                }
                return track
            })
            this.tracks = tracks
        })
        source.addEventListener('TrackDropped', ({ data }) => {
            const track: Track = Track.fromJSON(JSON.parse(data))
            this.tracks = this.tracks.filter($track => $track.id !== track.id)
        })
        source.addEventListener('TrackChanged', ({ data }) => {
            const track: Track = Track.fromJSON(JSON.parse(data))
            this.tracks = this.tracks.map($track => $track.id === track.id ? track : $track)
        })
        source.addEventListener('Lagged', event => {
            console.log(event)
            // Refresh the page, refetching the list of tracks and ticks
            window.location = window.location
        })
        source.addEventListener('error', event => {
            error(event)
            window.location = window.location
        })
        window.addEventListener('beforeunload', () => source.close())
    }
    async repopulate() {
        this.state = State.Fetching
        this.tracks = await Track.fetchAll()
    }
    async populate() {
        if (this.state != State.Unfetched) return
        await this.repopulate()
        this.streamUpdatesFromServer()
        this.state = State.Fetched
    }
    async taskCompleted(track: Track, date: Date): Promise<Tick> {
        const query = dateQuery(date)
        const response: Response = await fetch(`/api/v1/tracks/${track.id}/ticked?${query.toString()}`, { method: "PATCH" })
        const body = await response.text()
        if (!response.ok) {
            error(body)
            throw new Error(`error setting tick for track ${track.id} ("${track.name}"): ${response.status} ${response.statusText}`)
        }
        return JSON.parse(body)
    }
    async taskMarkedIncomplete(track: Track, date: Date) {
        const query = dateQuery(date)
        const { ok, status, statusText } = await fetch(`/api/v1/tracks/${track.id}/all-ticks?${query.toString()}`, { method: 'DELETE' })
        if (!ok)
            error(`error deleting ticks for ${track.id}: ${statusText} (${status})`)
    }
    async addTrack(track: Track): Promise<boolean> {
        const response = await fetch('/api/v1/tracks', {
            method: "POST",
            body: JSON.stringify(track),
            headers: { "Content-Type": "application/json" }
        })
        if (!response.ok)
            error(`error submitting track: ${track}: ${response.statusText} (${response.status})`)
        return response.ok
    }
    async removeTrack(trackID: number) {
        const response = await fetch(`/api/v1/tracks/${trackID}`, { method: "DELETE" })
        if (!response.ok) error(`error deleting track with ID ${trackID}: ${response.statusText} (${response.status})`)
    }
}

export const state = reactive(new AppState)