import { promises as fs } from 'fs'
import type { IconifyJSON } from '@iconify/types'
import type { FullIconifyIcon } from '@iconify/utils'
import { defaultCustomisations as DefaultIconCustomizations, iconToSVG, getIconData, tryInstallPkg } from '@iconify/utils';
import createDebugger from 'debug'
import { isPackageExists, resolveModule } from 'local-pkg'

const debug = createDebugger('@iconify-core:icon')
const debugModern = createDebugger('@iconify-core:modern')
const debugLegacy = createDebugger('@iconify-core:legacy')

export interface ResolvedIconPath {
	collection: string
	icon: string
	query: Record<string, string | undefined>
}

const _collections: Record<string, Promise<IconifyJSON | undefined>> = {}
const isLegacyExists = isPackageExists('@iconify/json')

export async function loadCollection(name: string, autoInstall = false): Promise<IconifyJSON | undefined> {
	if (!_collections[name])
		_collections[name] = task()

	return _collections[name]

	async function task(): Promise<IconifyJSON | undefined> {
		let jsonPath = resolveModule(`@iconify-json/${name}/icons.json`)
		if (jsonPath)
			debugModern(name)

		if (!jsonPath && isLegacyExists) {
			jsonPath = resolveModule(`@iconify/json/json/${name}.json`)
			if (jsonPath)
				debugLegacy(name)
		}

		if (!jsonPath && !isLegacyExists && autoInstall) {
			await tryInstallPkg(`@iconify-json/${name}`)
			jsonPath = resolveModule(`@iconify-json/${name}/icons.json`)
		}

		if (jsonPath) {
			return JSON.parse(await fs.readFile(jsonPath, 'utf8'))
		}
		else {
			debugModern(`failed to load ${name}`)
			return undefined
		}
	}
}

export function searchForIcon(iconSet: IconifyJSON, collection: string, ids: string[], scale = 1): FullIconifyIcon | null {
	let iconData: FullIconifyIcon | null
	for (const id of ids) {
		iconData = getIconData(iconSet, id, true)
		if (iconData) {
			debug(`${collection}:${id}`)
			const { attributes, body } = iconToSVG(iconData, {
				...DefaultIconCustomizations,
				height: `${scale}em`,
				width: `${scale}em`,
			})
			return `<svg ${Object.entries(attributes).map(i => `${i[0]}="${i[1]}"`).join(' ')}>${body}</svg>`
		}
	}
	return null
}