File Dialog

import { browser, to_readable, to_writable } from "@sveu/shared"
import { contains } from "@sveu/shared/dicts"

import type { FileDialogOptions } from "../utils"

const DEFAULT_OPTIONS: FileDialogOptions = {
    multiple: true,
    accept: "*",
}

/**
 * Open file dialog with ease.
 *
 * @param options - Options
 * - `multiple` - Allowed multiple files selection.
 * - `accept` - Allowed file types.
 * - `capture` - Capture mode.
 *
 * @returns
 * - `files` - The files selected.
 * - `accepted` - The files accepted.
 * - `rejected` - The files rejected.
 * - `open` - Open file dialog.
 * - `reset` - Reset file dialog.
 */
export function file_dialog(options: FileDialogOptions = {}) {
    const files = to_writable<FileList | null>(null)

    const accepted = to_writable<File[] | null>(null)

    const rejected = to_writable<File[] | null>(null)

    let input: HTMLInputElement | undefined

    if (browser) {
        input = document.createElement("input")
        input.type = "file"

        input.onchange = (event: Event) => {
            const result = event.target as HTMLInputElement

            files.set(result.files)

            if (result.accept && result.files && result.accept !== "*") {
                const _accepted = Array.from(result.files).filter((file) => {
                    const regex = new RegExp(result.accept.replace(/\*/g, ".*"))
                    return regex.test(file.type)
                })

                const _rejected = Array.from(result.files).filter((file) => {
                    const regex = new RegExp(result.accept.replace(/\*/g, ".*"))
                    return !regex.test(file.type)
                })

                accepted.set(_accepted)

                rejected.set(_rejected)
            }
        }
    }

    /**
     * Open file dialog.
     *
     * @param local_options - Override default options.
     *
     */
    function open(local_options?: Partial<FileDialogOptions>) {
        if (!input) return

        const _options = {
            ...DEFAULT_OPTIONS,
            ...options,
            ...local_options,
        }

        input.multiple = _options.multiple ?? true

        input.accept = _options.accept ?? "*"

        if (contains(_options, "capture"))
            input.capture = _options.capture ?? ""

        input.click()
    }

    /** Reset file dialog. */
    function reset() {
        files.set(null)

        accepted.set(null)

        rejected.set(null)

        if (input) input.value = ""
    }

    return {
        files: to_readable(files),
        accepted: to_readable(accepted),
        rejected: to_readable(rejected),
        open,
        reset,
    }
}