import { Event } from 'nostr-tools'
import { getTagValue } from './nostr'
import { ModDetails } from '../types'

/**
 * Extracts and normalizes mod data from an event.
 *
 * This function extracts specific tag values from an event and maps them to properties
 * of a `PageData` object. It handles default values and type conversions as needed.
 *
 * @param event - The event object from which to extract data.
 * @returns A `Partial<PageData>` object containing extracted data.
 */
export const extractModData = (event: Event): ModDetails => {
  // Helper function to safely get the first value of a tag or return a default value
  const getFirstTagValue = (tagIdentifier: string, defaultValue = '') => {
    const tagValue = getTagValue(event, tagIdentifier)
    return tagValue ? tagValue[0] : defaultValue
  }

  // Helper function to safely parse integer values from tags
  const getIntTagValue = (tagIdentifier: string, defaultValue: number = -1) => {
    const tagValue = getTagValue(event, tagIdentifier)
    return tagValue ? parseInt(tagValue[0], 10) : defaultValue
  }

  return {
    author: event.pubkey,
    edited_at: event.created_at,
    body: event.content,
    site: getFirstTagValue('t'),
    published_at: getIntTagValue('published_at'),
    game: getFirstTagValue('game'),
    title: getFirstTagValue('title'),
    featuredImageUrl: getFirstTagValue('featuredImageUrl'),
    summary: getFirstTagValue('summary'),
    nsfw: Boolean(getFirstTagValue('nsfw')),
    screenshotsUrls: getTagValue(event, 'screenshotsUrls') || [],
    tags: getTagValue(event, 'tags') || [],
    downloadUrls: (getTagValue(event, 'downloadUrls') || []).map((item) =>
      JSON.parse(item)
    )
  }
}

/**
 * Constructs a list of `ModDetails` objects from an array of events.
 *
 * This function filters out events that do not contain all required data,
 * extracts the necessary information from the valid events, and constructs
 * `ModDetails` objects.
 *
 * @param events - The array of event objects to be processed.
 * @returns An array of `ModDetails` objects constructed from valid events.
 */
export const constructModListFromEvents = (events: Event[]): ModDetails[] => {
  // Filter and extract mod details from events
  const modDetailsList: ModDetails[] = events
    .filter(isModDataComplete) // Filter out incomplete events
    .map((event) => extractModData(event)) // Extract data and construct ModDetails

  return modDetailsList
}

/**
 * Checks if the provided event contains all the required data for constructing a `ModDetails` object.
 *
 * This function verifies that the event has the necessary tags and values to construct a `ModDetails` object.
 *
 * @param event - The event object to be checked.
 * @returns `true` if the event contains all required data; `false` otherwise.
 */
export const isModDataComplete = (event: Event): boolean => {
  // Helper function to check if a tag value is present and not empty
  const hasTagValue = (tagIdentifier: string): boolean => {
    const value = getTagValue(event, tagIdentifier)
    return !!value && value.length > 0 && value[0].trim() !== ''
  }

  // Check if all required fields are present
  return (
    hasTagValue('t') &&
    hasTagValue('published_at') &&
    hasTagValue('game') &&
    hasTagValue('title') &&
    hasTagValue('featuredImageUrl') &&
    hasTagValue('summary') &&
    hasTagValue('nsfw') &&
    getTagValue(event, 'screenshotsUrls') !== null &&
    getTagValue(event, 'tags') !== null &&
    getTagValue(event, 'downloadUrls') !== null
  )
}