import path from 'path'
import get from 'lodash/get'
import consola from 'consola'

import { r } from './resolve'

export const flatRoutes = function flatRoutes(router, _path = '', routes = []) {
  router.forEach((r) => {
    if ([':', '*'].some(c => r.path.includes(c))) {
      return
    }
    /* istanbul ignore if */
    if (r.children) {
      if (_path === '' && r.path === '/') {
        routes.push('/')
      }
      return flatRoutes(r.children, _path + r.path + '/', routes)
    }
    _path = _path.replace(/^\/+$/, '/')
    routes.push(
      (r.path === '' && _path[_path.length - 1] === '/'
        ? _path.slice(0, -1)
        : _path) + r.path
    )
  })
  return routes
}

function cleanChildrenRoutes(routes, isChild = false, routeNameSplitter = '-') {
  let start = -1
  const regExpIndex = new RegExp(`${routeNameSplitter}index$`)
  const routesIndex = []
  routes.forEach((route) => {
    if (regExpIndex.test(route.name) || route.name === 'index') {
      // Save indexOf 'index' key in name
      const res = route.name.split(routeNameSplitter)
      const s = res.indexOf('index')
      start = start === -1 || s < start ? s : start
      routesIndex.push(res)
    }
  })
  routes.forEach((route) => {
    route.path = isChild ? route.path.replace('/', '') : route.path
    if (route.path.includes('?')) {
      const names = route.name.split(routeNameSplitter)
      const paths = route.path.split('/')
      if (!isChild) {
        paths.shift()
      } // clean first / for parents
      routesIndex.forEach((r) => {
        const i = r.indexOf('index') - start //  children names
        if (i < paths.length) {
          for (let a = 0; a <= i; a++) {
            if (a === i) {
              paths[a] = paths[a].replace('?', '')
            }
            if (a < i && names[a] !== r[a]) {
              break
            }
          }
        }
      })
      route.path = (isChild ? '' : '/') + paths.join('/')
    }
    route.name = route.name.replace(regExpIndex, '')
    if (route.children) {
      if (route.children.find(child => child.path === '')) {
        delete route.name
      }
      route.children = cleanChildrenRoutes(route.children, true, routeNameSplitter)
    }
  })
  return routes
}

const DYNAMIC_ROUTE_REGEX = /^\/([:*])/

const sortRoutes = function sortRoutes(routes) {
  routes.sort((a, b) => {
    if (!a.path.length) {
      return -1
    }
    if (!b.path.length) {
      return 1
    }
    // Order: /static, /index, /:dynamic
    // Match exact route before index: /login before /index/_slug
    if (a.path === '/') {
      return DYNAMIC_ROUTE_REGEX.test(b.path) ? -1 : 1
    }
    if (b.path === '/') {
      return DYNAMIC_ROUTE_REGEX.test(a.path) ? 1 : -1
    }

    let i
    let res = 0
    let y = 0
    let z = 0
    const _a = a.path.split('/')
    const _b = b.path.split('/')
    for (i = 0; i < _a.length; i++) {
      if (res !== 0) {
        break
      }
      y = _a[i] === '*' ? 2 : _a[i].includes(':') ? 1 : 0
      z = _b[i] === '*' ? 2 : _b[i].includes(':') ? 1 : 0
      res = y - z
      // If a.length >= b.length
      if (i === _b.length - 1 && res === 0) {
        // unless * found sort by level, then alphabetically
        res = _a[i] === '*' ? -1 : (
          _a.length === _b.length ? a.path.localeCompare(b.path) : (_a.length - _b.length)
        )
      }
    }

    if (res === 0) {
      // unless * found sort by level, then alphabetically
      res = _a[i - 1] === '*' && _b[i] ? 1 : (
        _a.length === _b.length ? a.path.localeCompare(b.path) : (_a.length - _b.length)
      )
    }
    return res
  })

  routes.forEach((route) => {
    if (route.children) {
      sortRoutes(route.children)
    }
  })

  return routes
}

export const createRoutes = function createRoutes(files, srcDir, pagesDir = '', routeNameSplitter = '-') {
  const supportedExtensions = ['vue', 'js', 'ts', 'tsx']
  const routes = []
  files.forEach((file) => {
    const keys = file
      .replace(new RegExp(`^${pagesDir}`), '')
      .replace(new RegExp(`\\.(${supportedExtensions.join('|')})$`), '')
      .replace(/\/{2,}/g, '/')
      .split('/')
      .slice(1)
    const route = { name: '', path: '', component: r(srcDir, file) }
    let parent = routes
    keys.forEach((key, i) => {
      // remove underscore only, if its the prefix
      const sanitizedKey = key.startsWith('_') ? key.substr(1) : key

      route.name = route.name
        ? route.name + routeNameSplitter + sanitizedKey
        : sanitizedKey
      route.name += key === '_' ? 'all' : ''
      route.chunkName = file.replace(new RegExp(`\\.(${supportedExtensions.join('|')})$`), '')
      const child = parent.find(parentRoute => parentRoute.name === route.name)

      if (child) {
        child.children = child.children || []
        parent = child.children
        route.path = ''
      } else if (key === 'index' && i + 1 === keys.length) {
        route.path += i > 0 ? '' : '/'
      } else {
        route.path += '/' + getRoutePathExtension(key)

        if (key.startsWith('_') && key.length > 1) {
          route.path += '?'
        }
      }
    })
    parent.push(route)
  })

  sortRoutes(routes)
  return cleanChildrenRoutes(routes, false, routeNameSplitter)
}

// Guard dir1 from dir2 which can be indiscriminately removed
export const guardDir = function guardDir(options, key1, key2) {
  const dir1 = get(options, key1, false)
  const dir2 = get(options, key2, false)

  if (
    dir1 &&
    dir2 &&
    (
      dir1 === dir2 ||
      (
        dir1.startsWith(dir2) &&
        !path.basename(dir1).startsWith(path.basename(dir2))
      )
    )
  ) {
    const errorMessage = `options.${key2} cannot be a parent of or same as ${key1}`
    consola.fatal(errorMessage)
    throw new Error(errorMessage)
  }
}

const getRoutePathExtension = (key) => {
  if (key === '_') {
    return '*'
  }

  if (key.startsWith('_')) {
    return `:${key.substr(1)}`
  }

  return key
}

export const promisifyRoute = function promisifyRoute(fn, ...args) {
  // If routes is an array
  if (Array.isArray(fn)) {
    return Promise.resolve(fn)
  }
  // If routes is a function expecting a callback
  if (fn.length === arguments.length) {
    return new Promise((resolve, reject) => {
      fn((err, routeParams) => {
        if (err) {
          reject(err)
        }
        resolve(routeParams)
      }, ...args)
    })
  }
  let promise = fn(...args)
  if (
    !promise ||
    (!(promise instanceof Promise) && typeof promise.then !== 'function')
  ) {
    promise = Promise.resolve(promise)
  }
  return promise
}