import {ensureNumber} from '@welshman/lib'
import type {Filter} from '@welshman/util'
import {Tags} from '@welshman/util'
import {
  FeedType,
  Feed,
  AddressFeed,
  AuthorFeed,
  CreatedAtFeed,
  DVMFeed,
  DifferenceFeed,
  IDFeed,
  IntersectionFeed,
  KindFeed,
  ListFeed,
  LabelFeed,
  WOTFeed,
  RelayFeed,
  ScopeFeed,
  SearchFeed,
  TagFeed,
  UnionFeed,
  TagFeedMapping,
  Scope,
  WOTItem,
  DVMItem,
  ListItem,
  LabelItem,
  CreatedAtItem,
} from './core'

export const makeAddressFeed =             (...addresses: string[]): AddressFeed       => [FeedType.Address, ...addresses]
export const makeAuthorFeed =              (...pubkeys: string[]): AuthorFeed          => [FeedType.Author, ...pubkeys]
export const makeCreatedAtFeed =           (...items: CreatedAtItem[]): CreatedAtFeed  => [FeedType.CreatedAt, ...items]
export const makeDVMFeed =                 (...items: DVMItem[]): DVMFeed              => [FeedType.DVM, ...items]
export const makeDifferenceFeed =          (...feeds: Feed[]): DifferenceFeed          => [FeedType.Difference, ...feeds]
export const makeIDFeed =                  (...ids: string[]): IDFeed                  => [FeedType.ID, ...ids]
export const makeIntersectionFeed =        (...feeds: Feed[]): IntersectionFeed        => [FeedType.Intersection, ...feeds]
export const makeKindFeed =                (...kinds: number[]): KindFeed              => [FeedType.Kind, ...kinds]
export const makeListFeed =                (...items: ListItem[]): ListFeed            => [FeedType.List, ...items]
export const makeLabelFeed =               (...items: LabelItem[]): LabelFeed          => [FeedType.Label, ...items]
export const makeWOTFeed =                 (...items: WOTItem[]): WOTFeed              => [FeedType.WOT, ...items]
export const makeRelayFeed =               (...urls: string[]): RelayFeed              => [FeedType.Relay, ...urls]
export const makeScopeFeed =               (...scopes: Scope[]): ScopeFeed             => [FeedType.Scope, ...scopes]
export const makeSearchFeed =              (...searches: string[]): SearchFeed         => [FeedType.Search, ...searches]
export const makeTagFeed =                 (key: string, ...values: string[]): TagFeed => [FeedType.Tag, key, ...values]
export const makeUnionFeed =               (...feeds: Feed[]): UnionFeed               => [FeedType.Union, ...feeds]

export const isAddressFeed =             (feed: Feed): feed is AddressFeed             => feed[0] === FeedType.Address
export const isAuthorFeed =              (feed: Feed): feed is AuthorFeed              => feed[0] === FeedType.Author
export const isCreatedAtFeed =           (feed: Feed): feed is CreatedAtFeed           => feed[0] === FeedType.CreatedAt
export const isDVMFeed =                 (feed: Feed): feed is DVMFeed                 => feed[0] === FeedType.DVM
export const isDifferenceFeed =          (feed: Feed): feed is DifferenceFeed          => feed[0] === FeedType.Difference
export const isIDFeed =                  (feed: Feed): feed is IDFeed                  => feed[0] === FeedType.ID
export const isIntersectionFeed =        (feed: Feed): feed is IntersectionFeed        => feed[0] === FeedType.Intersection
export const isKindFeed =                (feed: Feed): feed is KindFeed                => feed[0] === FeedType.Kind
export const isListFeed =                (feed: Feed): feed is ListFeed                => feed[0] === FeedType.List
export const isLabelFeed =               (feed: Feed): feed is LabelFeed               => feed[0] === FeedType.Label
export const isWOTFeed =                 (feed: Feed): feed is WOTFeed                 => feed[0] === FeedType.WOT
export const isRelayFeed =               (feed: Feed): feed is RelayFeed               => feed[0] === FeedType.Relay
export const isScopeFeed =               (feed: Feed): feed is ScopeFeed               => feed[0] === FeedType.Scope
export const isSearchFeed =              (feed: Feed): feed is SearchFeed              => feed[0] === FeedType.Search
export const isTagFeed =                 (feed: Feed): feed is TagFeed                 => feed[0] === FeedType.Tag
export const isUnionFeed =               (feed: Feed): feed is UnionFeed               => feed[0] === FeedType.Union

export function getFeedArgs(feed: IntersectionFeed | UnionFeed | DifferenceFeed): Feed[]
export function getFeedArgs(feed: AddressFeed | AuthorFeed | IDFeed | RelayFeed | SearchFeed): string[]
export function getFeedArgs(feed: CreatedAtFeed): CreatedAtItem[]
export function getFeedArgs(feed: ListFeed): ListItem[]
export function getFeedArgs(feed: LabelFeed): LabelItem[]
export function getFeedArgs(feed: DVMFeed): DVMItem[]
export function getFeedArgs(feed: WOTFeed): WOTItem[]
export function getFeedArgs(feed: ScopeFeed): Scope[]
export function getFeedArgs(feed: KindFeed): number[]
export function getFeedArgs(feed: TagFeed): [string, ...string[]]
export function getFeedArgs(feed: Feed) {
  switch (feed[0]) {
    case FeedType.Intersection:        return feed.slice(1) as Feed[]
    case FeedType.Union:               return feed.slice(1) as Feed[]
    case FeedType.Difference:          return feed.slice(1) as Feed[]
    case FeedType.Address:             return feed.slice(1) as string[]
    case FeedType.Author:              return feed.slice(1) as string[]
    case FeedType.ID:                  return feed.slice(1) as string[]
    case FeedType.Relay:               return feed.slice(1) as string[]
    case FeedType.Search:              return feed.slice(1) as string[]
    case FeedType.Tag:                 return feed.slice(1) as [string, ...string[]]
    case FeedType.CreatedAt:           return feed.slice(1) as CreatedAtItem[]
    case FeedType.List:                return feed.slice(1) as ListItem[]
    case FeedType.Label:               return feed.slice(1) as LabelItem[]
    case FeedType.DVM:                 return feed.slice(1) as DVMItem[]
    case FeedType.WOT:                 return feed.slice(1) as WOTItem[]
    case FeedType.Scope:               return feed.slice(1) as Scope[]
    case FeedType.Kind:                return feed.slice(1) as number[]
  }
}

export const hasSubFeeds = (feed: Feed): feed is IntersectionFeed | UnionFeed | DifferenceFeed =>
  [FeedType.Union, FeedType.Intersection, FeedType.Difference].includes(feed[0])

export const defaultTagFeedMappings: TagFeedMapping[] = [
  ['a', [FeedType.Address]],
  ['e', [FeedType.ID]],
  ['p', [FeedType.Author]],
  ['r', [FeedType.Relay]],
  ['t', [FeedType.Tag, '#t']],
]

export const feedsFromTags = (tags: Tags, mappings?: TagFeedMapping[]) => {
  const feeds = []

  for (const [tagName, templateFeed] of mappings || defaultTagFeedMappings) {
    const filterTags = tags.whereKey(tagName)

    if (filterTags.exists()) {
      let values: string[] | number[] = filterTags.values().valueOf()

      if (isKindFeed(templateFeed)) {
        values = values.map(ensureNumber) as number[]
      }

      feeds.push([...templateFeed, ...values] as Feed)
    }
  }

  return feeds
}

export const feedFromTags = (tags: Tags, mappings?: TagFeedMapping[]) =>
  makeIntersectionFeed(...feedsFromTags(tags, mappings))

export const feedsFromFilter = ({since, until, ...filter}: Filter) => {
  const feeds = []

  if (since && until) {
    feeds.push(makeCreatedAtFeed({since, until}))
  } else if (since) {
    feeds.push(makeCreatedAtFeed({since}))
  } else if (until) {
    feeds.push(makeCreatedAtFeed({until}))
  }

  for (const [k, v] of Object.entries(filter)) {
    if (k === 'ids') feeds.push(makeIDFeed(...v as string[]))
    else if (k === 'kinds') feeds.push(makeKindFeed(...v as number[]))
    else if (k === 'authors') feeds.push(makeAuthorFeed(...v as string[]))
    else if (k.startsWith('#')) feeds.push(makeTagFeed(k as string, ...v as string[]))
    else throw new Error(`Unable to create feed from filter ${k}: ${v}`)
  }

  return feeds
}

export const feedFromFilter = (filter: Filter) =>
  makeIntersectionFeed(...feedsFromFilter(filter))


export const walkFeed = (feed: Feed, visit: (feed: Feed) => void) => {
  visit(feed)

  if (hasSubFeeds(feed)) {
    for (const subFeed of getFeedArgs(feed)) {
      walkFeed(subFeed, visit)
    }
  }
}