import type { LeadPayload } from '../../shared/lead.ts'
import type { AmoCustomField, AmoFieldEntry } from './amocrm.ts'

/** Human labels used in the fallback note. */
const LABELS: Record<string, string> = {
  company: 'Медицинский центр',
  email: 'Email',
  phone: 'Телефон',
  profile: 'Основные направления центра',
  comment: 'Комментарий',
  page: 'Страница',
  referrer: 'Источник перехода',
  form: 'Форма',
  utm_source: 'utm_source',
  utm_medium: 'utm_medium',
  utm_campaign: 'utm_campaign',
  utm_content: 'utm_content',
  utm_term: 'utm_term',
}

/**
 * Candidate amoCRM field codes / name fragments for each piece of data we
 * collect. The first field in the account that matches wins; anything without
 * a match falls through to the lead note instead.
 */
const CANDIDATES: Record<string, { codes: string[]; names: string[] }> = {
  company: {
    codes: ['COMPANY', 'COMPANY_NAME'],
    names: ['компания', 'организация', 'медицинский центр', 'клиника', 'название центра', 'сеть'],
  },
  profile: {
    codes: ['PROFILE', 'SPECIALITY'],
    names: ['профиль', 'основной профиль', 'направление', 'специализация'],
  },
  comment: { codes: ['COMMENT', 'MESSAGE', 'DESCRIPTION'], names: ['комментарий', 'сообщение', 'описание заявки'] },
  page: { codes: ['REFERRER', 'PAGE'], names: ['страница', 'посадочная страница', 'url страницы'] },
  referrer: { codes: ['REFERER_URL'], names: ['источник перехода', 'referrer', 'реферер'] },
  form: { codes: ['FORMNAME', 'FORM_NAME'], names: ['название формы', 'форма'] },
  utm_source: { codes: ['UTM_SOURCE'], names: ['utm_source'] },
  utm_medium: { codes: ['UTM_MEDIUM'], names: ['utm_medium'] },
  utm_campaign: { codes: ['UTM_CAMPAIGN'], names: ['utm_campaign'] },
  utm_content: { codes: ['UTM_CONTENT'], names: ['utm_content'] },
  utm_term: { codes: ['UTM_TERM'], names: ['utm_term'] },
}

/** Field types we know how to write a plain string into. */
const TEXTUAL = new Set(['text', 'textarea', 'url', 'tracking_data', 'numeric', 'price', 'monetary'])
const ENUMERATED = new Set(['select', 'radiobutton', 'multiselect'])

const normalise = (value: string) =>
  value
    .toLowerCase()
    .replace(/ё/g, 'е')
    .replace(/[^a-zа-я0-9]+/gi, ' ')
    .trim()

export type LeadFieldMap = Map<string, AmoCustomField>

/** Picks one account field per payload key. A field is never used twice. */
export function resolveLeadFieldMap(fields: AmoCustomField[]): LeadFieldMap {
  const map: LeadFieldMap = new Map()
  const taken = new Set<number>()

  for (const [key, candidate] of Object.entries(CANDIDATES)) {
    const byCode = fields.find(
      (f) => f.code && candidate.codes.includes(f.code.toUpperCase()) && !taken.has(f.id),
    )
    const match =
      byCode ??
      fields.find((f) => {
        if (taken.has(f.id)) return false
        const name = normalise(f.name)
        return candidate.names.some((n) => name === normalise(n))
      }) ??
      fields.find((f) => {
        if (taken.has(f.id)) return false
        const name = normalise(f.name)
        return candidate.names.some((n) => name.includes(normalise(n)))
      })

    if (!match) continue
    if (!TEXTUAL.has(match.type) && !ENUMERATED.has(match.type)) continue
    map.set(key, match)
    taken.add(match.id)
  }

  return map
}

/** Builds one amoCRM field entry, or null when the value cannot be represented. */
function toFieldEntry(field: AmoCustomField, value: string): AmoFieldEntry | null {
  if (ENUMERATED.has(field.type)) {
    const target = normalise(value)
    const option = field.enums?.find((e) => normalise(e.value) === target)
    // An unmatched option would silently create garbage, so let it hit the note.
    return option ? { field_id: field.id, values: [{ value: option.value, enum_id: option.id }] } : null
  }

  if (field.type === 'numeric' || field.type === 'price' || field.type === 'monetary') {
    const numeric = Number(value.replace(/[^\d.,-]/g, '').replace(',', '.'))
    return Number.isFinite(numeric) ? { field_id: field.id, values: [{ value: numeric }] } : null
  }

  return { field_id: field.id, values: [{ value }] }
}

export interface MappedLead {
  fields: AmoFieldEntry[]
  /** Everything that had no matching field, ready to be written as a note. */
  note: string
}

export function mapLead(payload: LeadPayload, fieldMap: LeadFieldMap): MappedLead {
  const data: Record<string, string | undefined> = {
    company: payload.company,
    profile: payload.profile,
    comment: payload.comment,
    page: payload.page,
    referrer: payload.referrer,
    form: 'Заявка на запуск физиотерапии с нуля',
    ...payload.utm,
  }

  const fields: AmoFieldEntry[] = []
  const leftovers: string[] = []

  for (const [key, value] of Object.entries(data)) {
    if (!value) continue
    const field = fieldMap.get(key)
    const entry = field ? toFieldEntry(field, value) : null
    if (entry) fields.push(entry)
    else leftovers.push(`${LABELS[key] ?? key}: ${value}`)
  }

  // Contact details are always repeated in the note so a manager can read the
  // whole request without opening the linked contact card.
  const header = [
    'Заявка с лендинга «Физиотерапия с нуля для медицинского центра»',
    `${LABELS.phone}: ${payload.phone}`,
    payload.email ? `${LABELS.email}: ${payload.email}` : undefined,
  ].filter(Boolean) as string[]

  return { fields, note: [...header, ...leftovers].join('\n') }
}

/** Lead title shown in the pipeline. */
export function buildLeadName(payload: LeadPayload): string {
  return `Физиотерапия — ${payload.company ?? payload.name}`
}