import Plane from './plane.js'

/**
 * @template Event
 * @template Action
 * @template EventData
 * @template Field
 * @template FieldData
 * @typedef
 * {{event: Event, action: Action, data: EventData, activity: {field: Field} & FieldData}}
 * GenericEvent
 */

/**
 * @typedef
 * {{
    "id": string,
    "cycle": {
      "id": string,
      "name": string,
      "start_date": string,
      "end_date": string,
      "created_by": string,
      "updated_by": string,
      "project": string,
      "workspace": string,
      "owned_by": string
    },
    "labels": Array<unknown>,
    "assignees": Array<string>,
    "state": {
      "id": string,
      "name": string,
      "color": string,
      "group": import('./plane.js').StateGroup
    },
    "estimate_point": number,
    "name": string,
    "sequence_id": number,
    "description": unknown,
    "description_html": string,
    "description_stripped": string,
    "priority": string,
    "start_date": unknown,
    "target_date": unknown,
    "created_by": string,
    "updated_by": string,
    "project": string,
    "workspace": string,
    "parent": string | null
  }}
 * IssueEventData
 */

/** @typedef {{
      "id": string,
      "first_name": string,
      "last_name": string,
      "email": string,
      "avatar": string,
      "display_name": string
    }} 
    EventActor
 */

/** @typedef {GenericEvent<"issue", "created", IssueEventData, null, {actor: EventActor}>} EventIssueCreated */

/** @template Field @typedef {GenericEvent<"issue", "created", IssueEventData, Field, {actor: EventActor}>} EventIssueUpdated */

/**
 * @typedef
 * {EventIssueCreated | EventIssueUpdated<"description"> | GenericEvent<unknown, unknown, unknown, unknown, unknown>}
 * Event
 */

/** @type {(e: Event) => e is GenericEvent<"issue", unknown, IssueEventData, unknown, {actor: EventActor}>} */
export const isIssue = e => e.event === 'issue'

/** @type {(e: Event) => e is EventIssueCreated} */
export const isIssueCreated = e =>
  e.event === 'issue' && e.action === 'created' && e.activity.field === null

/** @type {(e: Event) => e is EventIssueUpdated<"description">} */
export const isIssueDescriptionUpdated = e =>
  e.event === 'issue' &&
  typeof e.action === 'string' &&
  ['created', 'updated'].includes(e.action) &&
  e.activity.field === 'description'

/** @type {(e: Event) => e is EventIssueUpdated<"estimate_point">} */
export const isIssueEstimateUpdated = e =>
  e.event === 'issue' &&
  typeof e.action === 'string' &&
  ['created', 'updated'].includes(e.action) &&
  e.activity.field === 'estimate_point'

/** @type {(e: Event) => e is EventIssueUpdated<"state">} */
export const isIssueStateUpdated = e =>
  e.event === 'issue' && e.action === 'updated' && e.activity.field === 'state'

/** @type {(e: Event) => e is EventIssueUpdated<"name">} */
export const isIssueTitleUpdated = e =>
  e.event === 'issue' && e.action === 'updated' && e.activity.field === 'name'

/** @type {(c: import('./plane.js').Config, p: string, i: string) => string} */
export const issueURL = (c, project, issue) =>
  c.baseURI + '/' + c.workspace + '/projects/' + project + '/issues/' + issue

/** @type {(plane: import('./plane.js').Config, e: Event) => Promise<{content: string, topic: string}>} */
export default async (plane, ev) => {
  if (isIssue(ev)) {
    const user = `\`${ev.activity.actor.display_name}\``
    const description = ev.data.description_stripped.trim()
      ? `> ${ev.data.description_stripped.trim()}`
      : ''

    const parent = await (async () => {
      if (!ev.data.parent) {
        return null
      }
      return Plane.Issue.get(plane, ev.data.project, ev.data.parent)
    })()

    const subIssues = await (async () => {
      const id = (parent || ev.data).id
      const allIssues = await Plane.Issue.getAll(plane, ev.data.project)
      return allIssues.filter(i => i.parent === id)
    })()

    /** @type {(_: {sequence_id: number, name: string, project: string, id: string}) => string} */
    const link = ({ sequence_id, name, project, id }) =>
      `**[CORE-${sequence_id}](${issueURL(plane, project, id)}) ${name}**`
    const thisLink = link(ev.data)
    const title = parent ? link(parent) + '\n⤷ ' + link(ev.data) : link(ev.data)
    const topic = parent
      ? 'CORE-' + parent.sequence_id
      : 'CORE-' + ev.data.sequence_id

    /** @type {(g: import('./plane.js').StateGroup) => string} */
    const stateEmoji = s =>
      s === 'completed'
        ? ':check:'
        : s === 'started'
          ? ':yellow_large_square:'
          : ':white_large_square:'

    const state = `${stateEmoji(ev.data.state.group)} ${ev.data.state.name}`

    const subIssueSummary = await (async () => {
      const states = await Plane.State.getAll(plane, ev.data.project)
      /** @type {Record<string, import('./plane.js').State>}*/
      const stateMap = {}
      states.forEach(s => {
        stateMap[s.id] = s
      })

      /** @type {(s: import('./plane.js').StateGroup) => Array<import('./plane.js').Issue>} */
      const by_state = state =>
        subIssues.flatMap(i => {
          const s = stateMap[i.state]
          if (!s) return []
          if (s.group !== state) return []
          if (i.id === ev.data.id)
            return [{ ...ev.data, state: ev.data.state.id }]
          return [i]
        })

      return (
        '**Sub-issues**\n' +
        by_state('completed')
          .concat(by_state('started'))
          .concat(by_state('unstarted'))
          .concat(by_state('backlog'))
          .map(i => ' - ' + stateEmoji(stateMap[i.state].group) + ' ' + link(i))
          .join('\n')
      )
    })()

    /** @type {Record<string, string>} */
    const estimateMap = {
      0: '**XS** (Extra Small)',
      1: '**S** (Small)',
      2: '**M** (Medium)',
      3: '**L** (Large)',
      4: '**XL** (Extra Large)',
    }

    if (isIssueCreated(ev) && !!parent) {
      return {
        topic,
        content: `${title}\n${user} created sub-issue ${thisLink}\n${subIssueSummary}`,
      }
    } else if (isIssueCreated(ev)) {
      return { topic, content: `${title}\n${user} created issue` }
    } else if (isIssueEstimateUpdated(ev)) {
      return {
        topic,
        content: `${title}\n${user} set estimate to ${estimateMap[ev.data.estimate_point.toString()]}`,
      }
    } else if (isIssueTitleUpdated(ev)) {
      return {
        topic,
        content: `${title}\n${user} updated title to ${ev.data.name}`,
      }
    } else if (isIssueDescriptionUpdated(ev)) {
      return {
        topic,
        content: `${title}\n${user} updated description\n${description}`,
      }
    } else if (isIssueStateUpdated(ev) && !!parent) {
      return {
        topic,
        content: `${title}\n${user} changed ${thisLink}'s state to ${state}\n${subIssueSummary}`,
      }
    } else if (isIssueStateUpdated(ev)) {
      return { topic, content: `${title}\n${user} changed state to ${state}` }
    }
  }

  return {
    topic: 'unknown',
    content: '```json\n' + JSON.stringify(ev, null, 2) + '\n```',
  }
}