import { formatNumber, t } from '@/i18n'
import type { BuiltinField } from '@/lib/contentTypes'
import { fieldTypeSpec, type FieldCellKind } from '@/lib/fieldTypes'
import { formatDayValue } from '@/lib/entryValue'
import { isMissingImage, type MediaSummary } from '@/lib/mediaField'
import { isMissingRelation, relationIdsOf, type RelationSummary } from '@/lib/relationField'
import { formatAbsoluteDateFromIso } from '@/lib/relativeDate'

export { formatDayValue }

export type CellKind = 'empty' | FieldCellKind

export interface RelationChip {
	id: number
	label: string
	missing: boolean
}

export interface CellView {
	kind: CellKind
	text: string
	yes?: boolean
	image?: MediaSummary
	chips?: RelationChip[]
	more?: number
}

export const RELATION_CHIPS_SHOWN = 2

export const EMPTY_TEXT = '–'

const EMPTY: CellView = { kind: 'empty', text: '' }
const LINE_PREFIX = /^\s{0,3}(?:#{1,6}(?:\s+|$)|>\s?|[-*+]\s+|\d+[.)]\s+)+/
const IMAGE_OR_LINK = /!?\[([^\]]*)\]\([^)]*\)/g
const EMPHASIS = /(\*\*|__|\*|`|~~)/g
const UNDERSCORE_EMPHASIS = /(^|[\s(])_(?=\S)([^_]*?\S)_(?=$|[\s).,;:!?])/g

export function richTextFirstLine(markdown: string) {
	for (const line of markdown.split(/\r?\n/)) {
		const plain = line
			.replace(LINE_PREFIX, '')
			.replace(IMAGE_OR_LINK, '$1')
			.replace(EMPHASIS, '')
			.replace(UNDERSCORE_EMPHASIS, '$1$2')
			.trim()
		if (plain) {
			return plain
		}
	}
	return ''
}

function thumbnailCell(value: unknown, image: MediaSummary | undefined): CellView {
	const shown = image ?? { id: Number(value), missing: true as const }
	return {
		kind: 'thumbnail',
		text: isMissingImage(shown) ? '' : shown.filename,
		image: shown,
	}
}

function summaryField(first: { key: string; type: string }): BuiltinField {
	return {
		key: first.key,
		label: '',
		type: first.type,
		required: false,
		unique: false,
		default: null,
		min: null,
		max: null,
		options: null,
	}
}

export function relationLabel(summary: RelationSummary) {
	if (isMissingRelation(summary)) {
		return t('Entry no longer exists')
	}
	const first = summary.first_field
	const cell = describeCell(summaryField(first), first.value)
	return cell.kind === 'empty' || cell.kind === 'thumbnail' || cell.kind === 'relation'
		? t('Entry {0}', [summary.id])
		: plainCellText(cell)
}

function relationCell(value: unknown, summaries: RelationSummary[]): CellView {
	const ids = relationIdsOf(value)
	if (ids.length === 0) {
		return EMPTY
	}
	const chips = ids.map((id): RelationChip => {
		const summary = summaries.find((candidate) => candidate.id === id) ?? {
			id,
			missing: true as const,
		}
		return { id, label: relationLabel(summary), missing: isMissingRelation(summary) }
	})
	return {
		kind: 'relation',
		text: chips.map((chip) => chip.label).join(', '),
		chips: chips.slice(0, RELATION_CHIPS_SHOWN),
		more: Math.max(0, chips.length - RELATION_CHIPS_SHOWN),
	}
}

export function describeCell(
	field: BuiltinField,
	value: unknown,
	image?: MediaSummary,
	relations: RelationSummary[] = [],
): CellView {
	if (value === undefined || value === null || value === '') {
		return EMPTY
	}
	const kind = fieldTypeSpec(field.type).cell
	switch (kind) {
		case 'thumbnail':
			return thumbnailCell(value, image)
		case 'relation':
			return relationCell(value, relations)
		case 'boolean':
			return { kind, text: '', yes: value === true }
		case 'number':
			return { kind, text: typeof value === 'number' ? formatNumber(value) : String(value) }
		case 'date':
			return { kind, text: formatDayValue(String(value)) }
		case 'choice':
			return { kind, text: String(value) }
		case 'richtext': {
			const line = richTextFirstLine(String(value))
			return line ? { kind, text: line } : EMPTY
		}
		default:
			return { kind, text: String(value) }
	}
}

export function formatEntryDate(iso: string) {
	return formatAbsoluteDateFromIso(iso)
}

export function isEmptyCell(cell: CellView) {
	return cell.kind === 'empty'
}

export function plainCellText(cell: CellView) {
	if (cell.kind === 'empty') {
		return EMPTY_TEXT
	}
	if (cell.kind === 'boolean') {
		return cell.yes ? t('Yes') : t('No')
	}
	return cell.text || EMPTY_TEXT
}

export interface CardFields {
	first?: BuiltinField
	second?: BuiltinField
	choice?: BuiltinField
}

function isThumbnail(field: BuiltinField) {
	return fieldTypeSpec(field.type).cell === 'thumbnail'
}

export function thumbnailColumn(columns: BuiltinField[]) {
	return columns.find(isThumbnail)
}

export function cardFields(fields: BuiltinField[]): CardFields {
	const [first, ...rest] = fields
	const second = rest.find((field) => !isThumbnail(field))
	const choice = fields.find((field) => field.type === 'select')
	return { first, second, choice: choice === first ? undefined : choice }
}