import { formatNumber, t } from '@/i18n'
import type { ImageVariant, VariantFit, VariantFormat } from '@/composables/useImageVariants'

const BYTES_PER_KB = 1024
const BYTES_PER_MB = BYTES_PER_KB * 1024
const KB_PER_MB = 1024
const MB_PER_GB = 1024
const NO_QUALITY = '—'
const SEPARATOR = ' · '

function oneDecimal(value: number) {
	return Math.round(value * 10) / 10
}

export function formatVariantSize(bytes: number) {
	const kilobytes = Math.round(bytes / BYTES_PER_KB)
	if (bytes === 0) {
		return t('{0} KB', [0])
	}
	if (kilobytes < KB_PER_MB) {
		return t('{0} KB', [Math.max(1, kilobytes)])
	}
	const megabytes = bytes / BYTES_PER_MB
	if (megabytes < MB_PER_GB) {
		return t('{0} MB', [oneDecimal(megabytes)])
	}
	return t('{0} GB', [oneDecimal(megabytes / MB_PER_GB)])
}

export function formatDimensions(width: number | null, height: number | null) {
	if (width !== null && height !== null) {
		return `${width}×${height}`
	}
	if (width !== null) {
		return `${width} × ${t('auto')}`
	}
	return `${t('auto')} × ${height ?? ''}`
}

export function formatLabel(format: VariantFormat) {
	const labels: Record<VariantFormat, string> = {
		webp: 'WebP',
		jpeg: 'JPEG',
		png: 'PNG',
		original: t('Original'),
	}
	return labels[format]
}

export function fitLabel(fit: VariantFit) {
	const labels: Record<VariantFit, string> = {
		cover: t('cover'),
		contain: t('contain'),
		inside: t('inside'),
	}
	return labels[fit]
}

function hasQuality(variant: Pick<ImageVariant, 'format' | 'quality'>) {
	return variant.format !== 'png' && variant.quality !== null
}

export function qualityCell(variant: Pick<ImageVariant, 'format' | 'quality'>) {
	return hasQuality(variant) ? String(variant.quality) : NO_QUALITY
}

export function specLine(variant: ImageVariant) {
	const parts = [
		formatDimensions(variant.width, variant.height),
		fitLabel(variant.fit),
		formatLabel(variant.format),
	]
	if (hasQuality(variant)) {
		parts.push(t('q{0}', [variant.quality ?? 0]))
	}
	return parts.join(SEPARATOR)
}

export function generatedLine(variant: ImageVariant) {
	return t('{0} generated · {1}', [
		formatNumber(variant.generated_files),
		formatVariantSize(variant.cache_size),
	])
}

export function variantsSummary(items: readonly ImageVariant[]) {
	const files = items.reduce((total, item) => total + item.generated_files, 0)
	const bytes = items.reduce((total, item) => total + item.cache_size, 0)
	const variants = items.length === 1 ? t('1 variant') : t('{0} variants', [items.length])
	const generated =
		files === 1 ? t('1 generated file') : t('{0} generated files', [formatNumber(files)])
	return [variants, generated, formatVariantSize(bytes)].join(SEPARATOR)
}