import {computed, ref} from "vue";

const pending = ref(0)
const visible = ref(false)
let showTimer = null

const SHOW_DELAY_MS = 3000

const scheduleShow = () => {
    if (visible.value || showTimer) return

    showTimer = setTimeout(() => {
        showTimer = null
        if (pending.value > 0) {
            visible.value = true
        }
    }, SHOW_DELAY_MS)
}

const cancelScheduledShow = () => {
    if (!showTimer) return
    clearTimeout(showTimer)
    showTimer = null
}

export const startGlobalLoading = () => {
    pending.value += 1
    scheduleShow()
}

export const stopGlobalLoading = () => {
    pending.value = Math.max(0, pending.value - 1)

    if (pending.value === 0) {
        cancelScheduledShow()
        visible.value = false
    }
}

export const useGlobalLoading = () => {
    return {
        isGlobalLoading: computed(() => visible.value),
        pendingCount: computed(() => pending.value),
    }
}