import { Request, Response, NextFunction } from 'express'
import { topics, Topic, TopicNode } from '../models/topic'
import { finder, shortestPath } from '../utils'

// Create a topic
export const createTopic = (req: Request, res: Response, next: NextFunction) => {
  try {
    const { name, content, parentTopicId } = req.body
    const newTopic = new TopicNode(name, content, null, null, null, parentTopicId)
    topics.push(newTopic)

    res.status(201).json(newTopic)
  } catch (error) {
    next(error)
  }
}

// Retrieve all topics
export const getTopics = (req: Request, res: Response, next: NextFunction) => {
  try {
    res.json(topics)
  } catch (error) {
    next(error)
  }
}

// Retrieve single topic
export const getTopicById = (req: Request, res: Response, next: NextFunction) => {
  try {
    const id = parseInt(req.params.id, 10)
    const topic = topics.find((i) => i.id === id)
    if (!topic) {
      res.status(404).json({ message: 'Topic not found' })
      return
    }
    res.status(302).json(topic)
  } catch (error) {
    next(error)
  }
}

// Retrieve single version of a topic
export const getTopicByIdVersion = (req: Request, res: Response, next: NextFunction) => {
  try {
    const id = parseInt(req.params.id, 10)
    const version = parseInt(req.params.version, 10)
    const topic = topics.find((i) => i.id === id && i.version === version)
    if (!topic) {
      res.status(404).json({ message: 'Topic not found' })
      return
    }
    res.status(302).json(topic)
  } catch (error) {
    next(error)
  }
}

// Retrieve topic and all subtopics recursively
export const getTopicByIdRecursive = (req: Request, res: Response, next: NextFunction) => {
  try {
    const id = parseInt(req.params.id, 10)
    const topic = topics.find((i) => i.id === id)
    if (!topic) {
      res.status(404).json({ message: 'Topic not found' })
      return
    }
    const result = finder(topic.id)

    res.status(302).json(result)
  } catch (error) {
    next(error)
  }
}

// Update a topic (create nenw version)
export const updateTopic = (req: Request, res: Response, next: NextFunction) => {
  try {
    const id = parseInt(req.params.id, 10)
    const { name, content, parentTopicId } = req.body
    const oldTopicArray = topics.filter(t => t.id === id)

    if (oldTopicArray.length === 0) {
      res.status(404).json({ message: 'Topic not found' })
      return
    }

    const oldTopic = oldTopicArray[oldTopicArray.length - 1]
    const newTopic = oldTopic.update(name, content, parentTopicId)

    res.status(202).json(newTopic)
  } catch (error) {
    next(error)
  }
}

// Delete a topic
export const deleteTopic = (req: Request, res: Response, next: NextFunction) => {
  try {
    const id = parseInt(req.params.id, 10)
    const topicIndex = topics.findIndex((i) => i.id === id)
    if (topicIndex === -1) {
      res.status(404).json({ message: 'Topic not found' })
      return
    }
    const deletedTopic = topics.splice(topicIndex, 1)[0]
    res.status(202).json(deletedTopic)
  } catch (error) {
    next(error)
  }
}

// Find shortest path between topics
export const getShortestPath = (req: Request, res: Response, next: NextFunction) => {
  try {
    const idA = parseInt(req.params.idA, 10)
    const idB = parseInt(req.params.idB, 10)
    const result = shortestPath(idA, idB)

    if (result.length === 0 || result.name) {
      res.status(404).json('path does not exist')
    } else {
      res.status(302).json(result)
    }
  } catch (error) {
    next(error)
  }
}