import { ref, watch } from 'vue'
import { useApi } from '~/composables/useApi'

type FilterValue = string | number | boolean | null

export interface UseDataTableServerStateOptions {
    initialPerPage?: number
    debounceMs?: number
}

export function useDataTableServerState<T = Record<string, unknown>>(
    endpoint: string,
    initialFilters: Record<string, FilterValue> = {},
    options: UseDataTableServerStateOptions = {}
) {
    const api = useApi()

    const debounceMs = options.debounceMs ?? 300
    const initialPerPage = options.initialPerPage ?? 10

    const items = ref<T[]>([]) as { value: T[] }
    const totalItems = ref(0)
    const page = ref(1)
    const perPage = ref(initialPerPage)
    const filters = ref<Record<string, FilterValue>>({ ...initialFilters })
    const loading = ref(false)

    let debounceTimer: ReturnType<typeof setTimeout> | null = null
    let requestToken = 0

    const buildQueryParams = (): Record<string, string | number | boolean> => {
        const params: Record<string, string | number | boolean> = {
            page: page.value,
            itemsPerPage: perPage.value
        }
        for (const [key, value] of Object.entries(filters.value)) {
            if (value === '' || value === null) continue
            params[key] = value as string | number | boolean
        }
        return params
    }

    const fetchItems = async (): Promise<void> => {
        const currentToken = ++requestToken
        loading.value = true
        try {
            const data = await api.get<{ member: T[]; totalItems: number }>(
                endpoint,
                buildQueryParams(),
                {
                    toast: false,
                    headers: { Accept: 'application/ld+json' }
                }
            )
            if (currentToken !== requestToken) return
            items.value = data?.member ?? []
            totalItems.value = data?.totalItems ?? 0
        } finally {
            if (currentToken === requestToken) {
                loading.value = false
            }
        }
    }

    const reload = (): void => {
        if (debounceTimer) {
            clearTimeout(debounceTimer)
            debounceTimer = null
        }
        void fetchItems()
    }

    const scheduleReload = (): void => {
        if (debounceTimer) clearTimeout(debounceTimer)
        debounceTimer = setTimeout(() => {
            debounceTimer = null
            void fetchItems()
        }, debounceMs)
    }

    watch([page, perPage], () => {
        reload()
    })

    watch(filters, () => {
        if (page.value !== 1) {
            page.value = 1
            return
        }
        scheduleReload()
    }, { deep: true })

    return {
        items,
        totalItems,
        page,
        perPage,
        filters,
        loading,
        reload
    }
}