const { Request, Response, NextFunction } = require('express')
const sequelize = require('sequelize')
const fs = require('../libs/fsExtra')
const { createNewSortInstance } = require('../libs/fastSort')

const Logger = require('../Logger')
const SocketAuthority = require('../SocketAuthority')
const Database = require('../Database')
const CacheManager = require('../managers/CacheManager')
const CoverManager = require('../managers/CoverManager')
const AuthorFinder = require('../finders/AuthorFinder')

const { reqSupportsWebp, isValidASIN } = require('../utils/index')

const naturalSort = createNewSortInstance({
  comparer: new Intl.Collator(undefined, { numeric: true, sensitivity: 'base' }).compare
})

/**
 * @typedef RequestUserObject
 * @property {import('../models/User')} user
 *
 * @typedef {Request & RequestUserObject} RequestWithUser
 *
 * @typedef RequestEntityObject
 * @property {import('../models/Author')} author
 *
 * @typedef {RequestWithUser & RequestEntityObject} AuthorControllerRequest
 */

class AuthorController {
  constructor() {}

  /**
   * GET: /api/authors/:id
   *
   * @param {AuthorControllerRequest} req
   * @param {Response} res
   */
  async findOne(req, res) {
    const include = (req.query.include || '').split(',')

    const authorJson = req.author.toOldJSON()

    // Used on author landing page to include library items and items grouped in series
    if (include.includes('items')) {
      authorJson.libraryItems = await Database.libraryItemModel.getForAuthor(req.author, req.user)

      if (include.includes('series')) {
        const seriesMap = {}
        // Group items into series
        authorJson.libraryItems.forEach((li) => {
          if (li.media.metadata.series) {
            li.media.metadata.series.forEach((series) => {
              const itemWithSeries = li.toJSONMinified()
              itemWithSeries.media.metadata.series = series

              if (seriesMap[series.id]) {
                seriesMap[series.id].items.push(itemWithSeries)
              } else {
                seriesMap[series.id] = {
                  id: series.id,
                  name: series.name,
                  items: [itemWithSeries]
                }
              }
            })
          }
        })
        // Sort series items
        for (const key in seriesMap) {
          seriesMap[key].items = naturalSort(seriesMap[key].items).asc((li) => li.media.metadata.series.sequence)
        }

        authorJson.series = Object.values(seriesMap)
      }

      // Minify library items
      authorJson.libraryItems = authorJson.libraryItems.map((li) => li.toJSONMinified())
    }

    return res.json(authorJson)
  }

  /**
   * PATCH: /api/authors/:id
   *
   * @param {AuthorControllerRequest} req
   * @param {Response} res
   */
  async update(req, res) {
    const keysToUpdate = ['name', 'description', 'asin']
    const payload = {}
    for (const key in req.body) {
      if (keysToUpdate.includes(key) && (typeof req.body[key] === 'string' || req.body[key] === null)) {
        payload[key] = req.body[key]
      }
    }
    if (!Object.keys(payload).length) {
      Logger.error(`[AuthorController] Invalid request payload. No valid keys found`, req.body)
      return res.status(400).send('Invalid request payload. No valid keys found')
    }

    let hasUpdated = false

    const authorNameUpdate = payload.name !== undefined && payload.name !== req.author.name
    if (authorNameUpdate) {
      payload.lastFirst = Database.authorModel.getLastFirst(payload.name)
    }

    // Check if author name matches another author and merge the authors
    let existingAuthor = null
    if (authorNameUpdate) {
      existingAuthor = await Database.authorModel.findOne({
        where: {
          id: {
            [sequelize.Op.not]: req.author.id
          },
          name: payload.name
        }
      })
    }
    if (existingAuthor) {
      Logger.info(`[AuthorController] Merging author "${req.author.name}" with "${existingAuthor.name}"`)
      const bookAuthorsToCreate = []
      const allItemsWithAuthor = await Database.authorModel.getAllLibraryItemsForAuthor(req.author.id)

      const oldLibraryItems = []
      allItemsWithAuthor.forEach((libraryItem) => {
        // Replace old author with merging author for each book
        libraryItem.media.authors = libraryItem.media.authors.filter((au) => au.id !== req.author.id)
        libraryItem.media.authors.push({
          id: existingAuthor.id,
          name: existingAuthor.name
        })

        const oldLibraryItem = Database.libraryItemModel.getOldLibraryItem(libraryItem)
        oldLibraryItems.push(oldLibraryItem)

        bookAuthorsToCreate.push({
          bookId: libraryItem.media.id,
          authorId: existingAuthor.id
        })
      })
      if (oldLibraryItems.length) {
        await Database.removeBulkBookAuthors(req.author.id) // Remove all old BookAuthor
        await Database.createBulkBookAuthors(bookAuthorsToCreate) // Create all new BookAuthor
        for (const libraryItem of allItemsWithAuthor) {
          await libraryItem.saveMetadataFile()
        }
        SocketAuthority.emitter(
          'items_updated',
          oldLibraryItems.map((li) => li.toJSONExpanded())
        )
      }

      // Remove old author
      const oldAuthorJSON = req.author.toOldJSON()
      await req.author.destroy()
      SocketAuthority.emitter('author_removed', oldAuthorJSON)
      // Update filter data
      Database.removeAuthorFromFilterData(oldAuthorJSON.libraryId, oldAuthorJSON.id)

      // Send updated num books for merged author
      const numBooks = await Database.bookAuthorModel.getCountForAuthor(existingAuthor.id)
      SocketAuthority.emitter('author_updated', existingAuthor.toOldJSONExpanded(numBooks))

      res.json({
        author: existingAuthor.toOldJSON(),
        merged: true
      })
      return
    }

    // If lastFirst is not set, get it from the name
    if (!authorNameUpdate && !req.author.lastFirst) {
      payload.lastFirst = Database.authorModel.getLastFirst(req.author.name)
    }

    // Regular author update
    req.author.set(payload)
    if (req.author.changed()) {
      await req.author.save()
      hasUpdated = true
    }

    if (hasUpdated) {
      let numBooksForAuthor = 0
      if (authorNameUpdate) {
        const allItemsWithAuthor = await Database.authorModel.getAllLibraryItemsForAuthor(req.author.id)

        numBooksForAuthor = allItemsWithAuthor.length
        const oldLibraryItems = []
        // Update author name on all books
        for (const libraryItem of allItemsWithAuthor) {
          libraryItem.media.authors = libraryItem.media.authors.map((au) => {
            if (au.id === req.author.id) {
              au.name = req.author.name
            }
            return au
          })
          const oldLibraryItem = Database.libraryItemModel.getOldLibraryItem(libraryItem)
          oldLibraryItems.push(oldLibraryItem)

          await libraryItem.saveMetadataFile()
        }

        if (oldLibraryItems.length) {
          SocketAuthority.emitter(
            'items_updated',
            oldLibraryItems.map((li) => li.toJSONExpanded())
          )
        }
      } else {
        numBooksForAuthor = await Database.bookAuthorModel.getCountForAuthor(req.author.id)
      }

      SocketAuthority.emitter('author_updated', req.author.toOldJSONExpanded(numBooksForAuthor))
    }

    res.json({
      author: req.author.toOldJSON(),
      updated: hasUpdated
    })
  }

  /**
   * DELETE: /api/authors/:id
   * Remove author from all books and delete
   *
   * @param {AuthorControllerRequest} req
   * @param {Response} res
   */
  async delete(req, res) {
    Logger.info(`[AuthorController] Removing author "${req.author.name}"`)

    if (req.author.imagePath) {
      await CacheManager.purgeImageCache(req.author.id) // Purge cache
    }

    await req.author.destroy()

    SocketAuthority.emitter('author_removed', req.author.toOldJSON())

    // Update filter data
    Database.removeAuthorFromFilterData(req.author.libraryId, req.author.id)

    res.sendStatus(200)
  }

  /**
   * POST: /api/authors/:id/image
   * Upload author image from web URL
   *
   * @param {AuthorControllerRequest} req
   * @param {Response} res
   */
  async uploadImage(req, res) {
    if (!req.user.canUpload) {
      Logger.warn(`User "${req.user.username}" attempted to upload an image without permission`)
      return res.sendStatus(403)
    }
    if (!req.body.url) {
      Logger.error(`[AuthorController] Invalid request payload. 'url' not in request body`)
      return res.status(400).send(`Invalid request payload. 'url' not in request body`)
    }
    if (!req.body.url.startsWith?.('http:') && !req.body.url.startsWith?.('https:')) {
      Logger.error(`[AuthorController] Invalid request payload. Invalid url "${req.body.url}"`)
      return res.status(400).send(`Invalid request payload. Invalid url "${req.body.url}"`)
    }

    Logger.debug(`[AuthorController] Requesting download author image from url "${req.body.url}"`)
    const result = await AuthorFinder.saveAuthorImage(req.author.id, req.body.url)

    if (result?.error) {
      return res.status(400).send(result.error)
    } else if (!result?.path) {
      return res.status(500).send('Unknown error occurred')
    }

    if (req.author.imagePath) {
      await CacheManager.purgeImageCache(req.author.id) // Purge cache
    }

    req.author.imagePath = result.path
    // imagePath may not have changed, but we still want to update the updatedAt field to bust image cache
    req.author.changed('imagePath', true)
    await req.author.save()

    const numBooks = await Database.bookAuthorModel.getCountForAuthor(req.author.id)
    SocketAuthority.emitter('author_updated', req.author.toOldJSONExpanded(numBooks))
    res.json({
      author: req.author.toOldJSON()
    })
  }

  /**
   * DELETE: /api/authors/:id/image
   * Remove author image & delete image file
   *
   * @param {AuthorControllerRequest} req
   * @param {Response} res
   */
  async deleteImage(req, res) {
    if (!req.author.imagePath) {
      Logger.error(`[AuthorController] Author "${req.author.imagePath}" has no imagePath set`)
      return res.status(400).send('Author has no image path set')
    }
    Logger.info(`[AuthorController] Removing image for author "${req.author.name}" at "${req.author.imagePath}"`)
    await CacheManager.purgeImageCache(req.author.id) // Purge cache
    await CoverManager.removeFile(req.author.imagePath)
    req.author.imagePath = null
    await req.author.save()

    const numBooks = await Database.bookAuthorModel.getCountForAuthor(req.author.id)
    SocketAuthority.emitter('author_updated', req.author.toOldJSONExpanded(numBooks))
    res.json({
      author: req.author.toOldJSON()
    })
  }

  /**
   * POST: /api/authors/:id/match
   *
   * @param {AuthorControllerRequest} req
   * @param {Response} res
   */
  async match(req, res) {
    let authorData = null
    const region = req.body.region || 'us'
    if (req.body.asin && isValidASIN(req.body.asin.toUpperCase?.())) {
      authorData = await AuthorFinder.findAuthorByASIN(req.body.asin, region)
    } else {
      authorData = await AuthorFinder.findAuthorByName(req.body.q, region)
    }
    if (!authorData) {
      return res.status(404).send('Author not found')
    }
    Logger.debug(`[AuthorController] match author with "${req.body.q || req.body.asin}"`, authorData)

    let hasUpdates = false
    if (authorData.asin && req.author.asin !== authorData.asin) {
      req.author.asin = authorData.asin
      hasUpdates = true
    }

    // Only updates image if there was no image before or the author ASIN was updated
    if (authorData.image && (!req.author.imagePath || hasUpdates)) {
      await CacheManager.purgeImageCache(req.author.id)

      const imageData = await AuthorFinder.saveAuthorImage(req.author.id, authorData.image)
      if (imageData?.path) {
        req.author.imagePath = imageData.path
        hasUpdates = true
      }
    }

    if (authorData.description && req.author.description !== authorData.description) {
      req.author.description = authorData.description
      hasUpdates = true
    }

    if (hasUpdates) {
      await req.author.save()

      const numBooks = await Database.bookAuthorModel.getCountForAuthor(req.author.id)
      SocketAuthority.emitter('author_updated', req.author.toOldJSONExpanded(numBooks))
    }

    res.json({
      updated: hasUpdates,
      author: req.author.toOldJSON()
    })
  }

  /**
   * GET: /api/authors/:id/image
   *
   * @param {AuthorControllerRequest} req
   * @param {Response} res
   */
  async getImage(req, res) {
    const {
      query: { width, height, format, raw },
      author
    } = req

    if (!author.imagePath || !(await fs.pathExists(author.imagePath))) {
      Logger.warn(`[AuthorController] Author "${author.name}" has invalid imagePath: ${author.imagePath}`)
      return res.sendStatus(404)
    }

    if (raw) {
      return res.sendFile(author.imagePath)
    }

    const options = {
      format: format || (reqSupportsWebp(req) ? 'webp' : 'jpeg'),
      height: height ? parseInt(height) : null,
      width: width ? parseInt(width) : null
    }
    return CacheManager.handleAuthorCache(res, author, options)
  }

  /**
   *
   * @param {RequestWithUser} req
   * @param {Response} res
   * @param {NextFunction} next
   */
  async middleware(req, res, next) {
    const author = await Database.authorModel.findByPk(req.params.id)
    if (!author) return res.sendStatus(404)

    if (req.method == 'DELETE' && !req.user.canDelete) {
      Logger.warn(`[AuthorController] User "${req.user.username}" attempted to delete without permission`)
      return res.sendStatus(403)
    } else if ((req.method == 'PATCH' || req.method == 'POST') && !req.user.canUpdate) {
      Logger.warn(`[AuthorController] User "${req.user.username}" attempted to update without permission`)
      return res.sendStatus(403)
    }

    req.author = author
    next()
  }
}
module.exports = new AuthorController()