/**
 * Mapping ActivityPub accounts onto a 2005 profile page.
 *
 * A MySpace profile had a fixed vocabulary — a headline in quotes, a mood, an
 * "Interests" table with General/Music/Movies/Television/Books/Heroes rows, and
 * blurbs for "About me" and "Who I'd like to meet". Mastodon has none of that;
 * it has a bio and up to four free-form key/value fields.
 *
 * The mapping is: profile fields whose name matches a known MySpace row fill
 * that row, leftover fields land in a generic details table, and the bio is
 * split into the two blurbs on a "who I'd like to meet"-ish heading if the user
 * wrote one. Users opt in to the richer layout simply by naming their fields
 * `Music`, `Movies`, `Mood` and so on.
 */

import type { Account } from '../api/types'
import { renderHtml, toPlainText } from './html'
import { topEightFromHtml } from './top-eight'

/** The interest rows a MySpace profile shipped with, in their original order. */
export const INTEREST_ROWS = ['General', 'Music', 'Movies', 'Television', 'Books', 'Heroes'] as const

export type InterestRow = (typeof INTEREST_ROWS)[number]

/** Field names that feed the chrome rather than a table row. */
const CHROME_FIELDS = new Set(['headline', 'mood', 'status', 'location', 'city', 'gender', 'pronouns', 'age'])

const ALIASES: Record<string, InterestRow> = {
  general: 'General',
  interests: 'General',
  about: 'General',
  music: 'Music',
  bands: 'Music',
  'now playing': 'Music',
  movies: 'Movies',
  film: 'Movies',
  films: 'Movies',
  television: 'Television',
  tv: 'Television',
  shows: 'Television',
  books: 'Books',
  reading: 'Books',
  heroes: 'Heroes',
  hero: 'Heroes',
  inspiration: 'Heroes',
}

export interface ProfileField {
  name: string
  /** Sanitized HTML. */
  value: string
  verified: boolean
}

export interface InterestEntry {
  row: InterestRow
  /** Sanitized HTML. */
  value: string
}

export interface ProfileView {
  account: Account
  /** The quoted line beside the photo. */
  headline: string
  mood: string | null
  location: string | null
  gender: string | null
  /** Age in years, from the account creation date unless a field overrides it. */
  age: number | null
  /** "About me" blurb, sanitized HTML. */
  about: string
  /** "Who I'd like to meet" blurb, sanitized HTML. Empty when the user wrote none. */
  wantsToMeet: string
  /** Fully-qualified handles declared in the portable bio section. */
  topEightHandles: string[]
  interests: InterestEntry[]
  details: ProfileField[]
}

/** Split a bio on a "who I'd like to meet" style heading, if one exists. */
function splitBio(noteHtml: string): { about: string; meet: string } {
  const marker = /(?:^|\n|<br\s*\/?>|<\/p>\s*<p>)\s*(?:who\s+i(?:'|’)?d\s+like\s+to\s+meet|looking\s+for)\s*:?/i
  const match = marker.exec(noteHtml)
  if (!match || match.index === undefined) return { about: noteHtml, meet: '' }
  return {
    about: noteHtml.slice(0, match.index),
    meet: noteHtml.slice(match.index + match[0].length),
  }
}

function findField(account: Account, names: string[]): string | null {
  for (const field of account.fields ?? []) {
    if (names.includes(field.name.trim().toLowerCase())) {
      const text = toPlainText(field.value)
      if (text) return text
    }
  }
  return null
}

/**
 * A stable, silly mood per account — MySpace always showed one, and an empty
 * "Mood:" line reads as a bug. Derived from the account id so it doesn't
 * flicker between renders.
 */
const MOODS = [
  'busy :-)',
  'productive :)',
  'awake',
  'jubilant',
  'chill',
  'working',
  'contemplative',
  'amused ;)',
  'nostalgic',
  'bouncy',
  'sleepy',
  'accomplished',
]

export function fallbackMood(seed: string): string {
  let hash = 0
  for (let index = 0; index < seed.length; index += 1) {
    hash = (hash * 31 + seed.charCodeAt(index)) >>> 0
  }
  return MOODS[hash % MOODS.length]
}

export function buildProfileView(account: Account): ProfileView {
  const renderedNote = renderHtml(account.note, { emojis: account.emojis })
  const topEight = topEightFromHtml(renderedNote)
  const noteHtml = topEight.html
  const { about, meet } = splitBio(noteHtml)

  const interests: InterestEntry[] = []
  const details: ProfileField[] = []

  for (const field of account.fields ?? []) {
    const key = field.name.trim().toLowerCase()
    // `plspace:` fields are application storage, not user-facing profile
    // details. Keep them on the Account for features such as published CSS,
    // but never turn them into visible name/value rows.
    if (key.startsWith('plspace:')) continue
    if (CHROME_FIELDS.has(key)) continue

    const value = renderHtml(field.value, { emojis: account.emojis })
    const row = ALIASES[key]
    if (row) {
      interests.push({ row, value })
    } else {
      details.push({
        name: field.name,
        value,
        verified: Boolean(field.verified_at),
      })
    }
  }

  // Keep the canonical MySpace ordering rather than the user's field order.
  interests.sort((a, b) => INTEREST_ROWS.indexOf(a.row) - INTEREST_ROWS.indexOf(b.row))

  const headlineField = findField(account, ['headline', 'status'])
  const headline = headlineField ?? firstSentence(toPlainText(noteHtml)) ?? '"..."'

  const ageField = findField(account, ['age'])
  const parsedAge = ageField ? Number.parseInt(ageField, 10) : Number.NaN

  return {
    account,
    headline,
    mood: findField(account, ['mood']) ?? fallbackMood(account.id || account.acct),
    location: findField(account, ['location', 'city']),
    gender: findField(account, ['gender', 'pronouns']),
    age: Number.isFinite(parsedAge) ? parsedAge : null,
    about,
    wantsToMeet: meet,
    topEightHandles: topEight.handles,
    interests,
    details,
  }
}

function firstSentence(text: string): string | null {
  if (!text) return null
  const match = /^.{0,120}?[.!?](?:\s|$)/.exec(text)
  const sentence = (match?.[0] ?? text.slice(0, 120)).trim()
  return sentence || null
}

/** `15,672,442` — friend counts were the whole point. */
export function formatCount(value: number | null | undefined): string {
  if (value === null || value === undefined || value < 0) return '0'
  return value.toLocaleString('en-US')
}

/** `@user@host`, always with the domain so remote accounts are unambiguous. */
export function fullHandle(account: Account, localHost: string): string {
  return account.acct.includes('@') ? `@${account.acct}` : `@${account.acct}@${localHost}`
}

/**
 * Whether an account's follower list is withheld.
 *
 * Mastodon signals this with `hide_collections`; Pleroma and Akkoma use
 * `pleroma.hide_followers` instead. Both then return an empty list, which is
 * indistinguishable from having no followers unless you check the flag.
 */
export function followersHidden(account: Account): boolean {
  return Boolean(account.hide_collections || account.pleroma?.hide_followers)
}

/**
 * Whether the follower *count* is withheld.
 *
 * Pleroma reports `followers_count: 0` when `hide_followers_count` is set, so
 * rendering that zero would state a privacy setting as fact.
 */
export function followerCountHidden(account: Account): boolean {
  return Boolean(account.pleroma?.hide_followers_count)
}

/** As above, for the accounts someone follows. */
export function followingCountHidden(account: Account): boolean {
  return Boolean(account.pleroma?.hide_follows_count)
}

/** The route this app uses for an account. */
export function profilePath(account: Account): string {
  return `#/@${account.acct}`
}

export function displayNameOf(account: Account): string {
  return account.display_name?.trim() || account.username
}