/*
  REST API validator middleware.
*/

const User = require('../../../adapters/localdb/models/users')
const config = require('../../../../config')
const jwt = require('jsonwebtoken')
const { wlogger } = require('../../../adapters/wlogger')

let _this

class Validators {
  constructor () {
    this.User = User
    this.jwt = jwt
    this.config = config

    _this = this
  }

  async ensureUser (ctx, next) {
    try {
      // console.log(`getToken: ${typeof (getToken)}`)
      const token = _this.getToken(ctx)

      if (!token) {
        // console.log(`Err: Token not provided.`)
        ctx.throw(401)
      }

      let decoded = null
      try {
        // console.log(`token: ${JSON.stringify(token, null, 2)}`)
        // console.log(`config: ${JSON.stringify(config, null, 2)}`)
        decoded = _this.jwt.verify(token, config.token)
      } catch (err) {
        // console.log(`Err: Token could not be decoded: ${err}`)
        ctx.throw(401)
      }

      ctx.state.user = await _this.User.findById(decoded.id, '-password')
      if (!ctx.state.user) {
        // console.log(`Err: Could not find user.`)
        ctx.throw(401)
      }

      // return next()
      return true
    } catch (error) {
      ctx.throw(401)
    }
  }

  // This funciton is almost identical to ensureUser, except at the end, it verifies
  // that the 'type' associated with the user equals 'admin'.
  async ensureAdmin (ctx, next) {
    try {
      // console.log(`getToken: ${typeof (getToken)}`)
      const token = _this.getToken(ctx)

      if (!token) {
        // console.log(`Err: Token not provided.`)
        ctx.throw(401)
      }

      let decoded = null
      try {
        // console.log(`token: ${JSON.stringify(token, null, 2)}`)
        // console.log(`config: ${JSON.stringify(config, null, 2)}`)
        decoded = _this.jwt.verify(token, config.token)
      } catch (err) {
        // console.log(`Err: Token could not be decoded: ${err}`)
        ctx.throw(401)
      }

      ctx.state.user = await _this.User.findById(decoded.id, '-password')
      if (!ctx.state.user) {
        // console.log(`Err: Could not find user.`)
        ctx.throw(401)
      }

      if (ctx.state.user.type !== 'admin') {
        ctx.throw(401, 'not admin')
      }

      // return next()
      return true
    } catch (error) {
      ctx.throw(401, error.message)
    }
  }

  // This middleware ensures that the :id used in the API endpoint matches the
  // the ID used in the JWT, or failing that, the ID used in the JWT matches
  // an Admin user. This prevents situations like users updating other users
  // profiles or non-admins deleting users.
  async ensureTargetUserOrAdmin (ctx, next) {
    try {
      // console.log(`getToken: ${typeof (getToken)}`)
      const token = _this.getToken(ctx)

      if (!token) {
        // console.log(`Err: Token not provided.`)
        ctx.throw(401)
      }

      // The user ID targeted in this API call.
      const targetId = ctx.params.id
      // console.log(`targetId: ${JSON.stringify(targetId, null, 2)}`)

      let decoded = null
      try {
        // console.log(`token: ${JSON.stringify(token, null, 2)}`)
        // console.log(`config: ${JSON.stringify(config, null, 2)}`)
        decoded = _this.jwt.verify(token, config.token)
      } catch (err) {
        // console.log(`Err: Token could not be decoded: ${err}`)
        ctx.throw(401)
      }

      ctx.state.user = await _this.User.findById(decoded.id, '-password')
      if (!ctx.state.user) {
        // console.log(`Err: Could not find user.`)
        ctx.throw(401)
      }
      // console.log('ctx.state.user: ', ctx.state.user)

      // console.log(`ctx.state.user: ${JSON.stringify(ctx.state.user, null, 2)}`)
      // Ensure the calling user and the target user are the same.

      if (ctx.state.user._id.toString() !== targetId.toString()) {
        wlogger.verbose(
          `Calling user and target user do not match! Calling user: ${ctx.state.user._id}, Target user: ${targetId}`
        )

        // If they don't match, then the calling user better be an admin.
        if (ctx.state.user.type !== 'admin') {
          ctx.throw(401, 'not admin')
        } else {
          wlogger.verbose("It's ok. The user is an admin.")
        }
      }

      // return next()
      return true
    } catch (error) {
      ctx.throw(401, error.message)
    }
  }

  getToken (ctx) {
    const header = ctx.request.header.authorization
    if (!header) {
      return null
    }
    const parts = header.split(' ')
    if (parts.length !== 2) {
      return null
    }
    const scheme = parts[0]
    const token = parts[1]
    if (/^Bearer$/i.test(scheme)) {
      return token
    }
    return null
  }
}

module.exports = Validators