import type { Event } from 'nostr-tools'
import type { Article, Page } from '@/types/nostr'
import { extractTagsFromEvent } from '../nostrTagSystem'
import { buildObjectId } from '../urlGenerator'
import { generateHashId } from '../hashIdGenerator'
import { getPreviewContent, mapNostrCategoryToLegacy, resolveObjectIdParts, resolveThumbnailUrl, type ExtractedTags } from './shared'

/**
 * Parse article metadata from Nostr event
 * Uses new tag system: #publication, #sciencefiction|research, #id_<id>, #paywall, #payment
 */
export async function parseArticleFromEvent(event: Event): Promise<Article | null> {
  try {
    const tags = extractTagsFromEvent(event)
    if (tags.type !== 'publication') {
      return null
    }
    const { previewContent } = getPreviewContent(event.content, tags.preview)
    return buildArticle(event, tags, previewContent)
  } catch (e) {
    console.error('Error parsing article:', e)
    return null
  }
}

function parsePagesFromEventJsonTag(event: Event): Page[] | undefined {
  const jsonTag = event.tags.find((tag) => tag[0] === 'json')?.[1]
  if (!jsonTag) {
    return undefined
  }
  try {
    const parsed: unknown = JSON.parse(jsonTag)
    if (typeof parsed !== 'object' || parsed === null) {
      return undefined
    }
    const metadata = parsed as { pages?: unknown }
    if (!Array.isArray(metadata.pages)) {
      return undefined
    }
    return metadata.pages as Page[]
  } catch {
    return undefined
  }
}

function buildArticlePaymentFields(tags: ExtractedTags): Partial<Article> {
  const result: Partial<Article> = {}
  if (tags.invoice) {
    result.invoice = tags.invoice
  }
  if (tags.paymentHash) {
    result.paymentHash = tags.paymentHash
  }
  return result
}

function buildArticleClassificationFields(params: {
  tags: ExtractedTags
  category: 'science-fiction' | 'scientific-research' | undefined
  isPresentation: boolean
}): Partial<Article> {
  const result: Partial<Article> = {}
  if (params.category) {
    result.category = params.category
  }
  if (params.isPresentation) {
    result.isPresentation = true
  }
  if (params.tags.type === 'publication' || params.tags.type === 'author') {
    result.kindType = 'article'
  }
  return result
}

function buildArticleOptionalMetaFields(params: { tags: ExtractedTags; pages: Page[] | undefined }): Partial<Article> {
  const result: Partial<Article> = {}
  if (params.tags.mainnetAddress) {
    result.mainnetAddress = params.tags.mainnetAddress
  }
  if (params.tags.totalSponsoring) {
    result.totalSponsoring = params.tags.totalSponsoring
  }
  if (params.tags.seriesId) {
    result.seriesId = params.tags.seriesId
  }
  if (params.tags.bannerUrl) {
    result.bannerUrl = params.tags.bannerUrl
  }
  if (params.pages && params.pages.length > 0) {
    result.pages = params.pages
  }
  return result
}

async function buildArticle(event: Event, tags: ExtractedTags, preview: string): Promise<Article> {
  const category = mapNostrCategoryToLegacy(tags.category)
  const isPresentation = tags.type === 'author'

  const { hash, version, index } = await resolveObjectIdParts(buildObjectIdResolutionParams({ event, tags, preview, isPresentation }))

  const id = buildObjectId(hash, index, version)
  const pages = parsePagesFromEventJsonTag(event)

  return {
    id,
    hash,
    version,
    index,
    pubkey: event.pubkey,
    title: tags.title ?? 'Untitled',
    preview,
    content: '',
    description: tags.description ?? '',
    contentDescription: tags.description ?? '',
    createdAt: event.created_at,
    zapAmount: tags.zapAmount ?? 800,
    paid: false,
    thumbnailUrl: resolveThumbnailUrl(tags),
    ...buildArticlePaymentFields(tags),
    ...buildArticleClassificationFields({ tags, category, isPresentation }),
    ...buildArticleOptionalMetaFields({ tags, pages }),
  }
}

function buildObjectIdResolutionParams(params: {
  event: Event
  tags: ExtractedTags
  preview: string
  isPresentation: boolean
}): Parameters<typeof resolveObjectIdParts>[0] {
  return {
    ...(params.tags.id ? { idTag: params.tags.id } : {}),
    defaultVersion: params.tags.version ?? 0,
    defaultIndex: 0,
    generateHash: async (): Promise<string> =>
      generateHashId({
        type: params.isPresentation ? 'author' : 'publication',
        pubkey: params.event.pubkey,
        title: params.tags.title ?? 'Untitled',
        preview: params.preview,
        category: params.tags.category ?? 'sciencefiction',
        seriesId: params.tags.seriesId ?? '',
        bannerUrl: params.tags.bannerUrl ?? '',
        zapAmount: params.tags.zapAmount ?? 800,
      }),
  }
}