import {
  NormalizedRoot,
  Path,
  dirname,
  join,
  normalize,
  relative,
} from "@angular-devkit/core"
import { DirEntry, Tree } from "@angular-devkit/schematics"

export interface ModuleOptions {
  module?: string
  name: string
  flat?: boolean
  path?: string
  skipImport?: boolean
  moduleExt?: string
  routingModuleExt?: string
  standalone?: boolean
}

export const MODULE_EXT = ".module.ts"
export const ROUTING_MODULE_EXT = "-routing.module.ts"

/**
 * Find the module referred by a set of options passed to the schematics.
 */
export function findModuleFromOptions(
  host: Tree,
  options: ModuleOptions
): Path | undefined {
  if (options.standalone || options.skipImport) {
    return undefined
  }

  const moduleExt = options.moduleExt || MODULE_EXT
  const routingModuleExt = options.routingModuleExt || ROUTING_MODULE_EXT

  if (!options.module) {
    const pathToCheck = (options.path || "") + "/" + options.name

    return normalize(findModule(host, pathToCheck, moduleExt, routingModuleExt))
  } else {
    const modulePath = normalize(`/${options.path}/${options.module}`)
    const componentPath = normalize(`/${options.path}/${options.name}`)
    const moduleBaseName = normalize(modulePath).split("/").pop()

    const candidateSet = new Set<Path>([normalize(options.path || "/")])

    for (let dir = modulePath; dir != NormalizedRoot; dir = dirname(dir)) {
      candidateSet.add(dir)
    }
    for (let dir = componentPath; dir != NormalizedRoot; dir = dirname(dir)) {
      candidateSet.add(dir)
    }

    const candidatesDirs = [...candidateSet].sort((a, b) => b.length - a.length)
    for (const c of candidatesDirs) {
      const candidateFiles = [
        "",
        `${moduleBaseName}.ts`,
        `${moduleBaseName}${moduleExt}`,
      ].map((x) => join(c, x))

      for (const sc of candidateFiles) {
        if (host.exists(sc)) {
          return normalize(sc)
        }
      }
    }

    throw new Error(
      `Specified module '${options.module}' does not exist.\n` +
        `Looked in the following directories:\n    ${candidatesDirs.join(
          "\n    "
        )}`
    )
  }
}

/**
 * Function to find the "closest" module to a generated file's path.
 */
export function findModule(
  host: Tree,
  generateDir: string,
  moduleExt = MODULE_EXT,
  routingModuleExt = ROUTING_MODULE_EXT
): Path {
  let dir: DirEntry | null = host.getDir("/" + generateDir)
  let foundRoutingModule = false

  while (dir) {
    const allMatches = dir.subfiles.filter((p) => p.endsWith(moduleExt))
    const filteredMatches = allMatches.filter(
      (p) => !p.endsWith(routingModuleExt)
    )

    foundRoutingModule =
      foundRoutingModule || allMatches.length !== filteredMatches.length

    if (filteredMatches.length == 1) {
      return join(dir.path, filteredMatches[0])
    } else if (filteredMatches.length > 1) {
      throw new Error(
        `More than one module matches. Use the '--skip-import' option to skip importing ` +
          "the component into the closest module or use the module option to specify a module."
      )
    }

    dir = dir.parent
  }

  const errorMsg = foundRoutingModule
    ? "Could not find a non Routing NgModule." +
      `\nModules with suffix '${routingModuleExt}' are strictly reserved for routing.` +
      `\nUse the '--skip-import' option to skip importing in NgModule.`
    : `Could not find an NgModule. Use the '--skip-import' option to skip importing in NgModule.`

  throw new Error(errorMsg)
}

/**
 * Build a relative path from one file path to another file path.
 */
export function buildRelativePath(from: string, to: string): string {
  from = normalize(from)
  to = normalize(to)

  // Convert to arrays.
  const fromParts = from.split("/")
  const toParts = to.split("/")

  // Remove file names (preserving destination)
  fromParts.pop()
  const toFileName = toParts.pop()

  const relativePath = relative(
    normalize(fromParts.join("/") || "/"),
    normalize(toParts.join("/") || "/")
  )
  let pathPrefix = ""

  // Set the path prefix for same dir or child dir, parent dir starts with `..`
  if (!relativePath) {
    pathPrefix = "."
  } else if (!relativePath.startsWith(".")) {
    pathPrefix = `./`
  }
  if (pathPrefix && !pathPrefix.endsWith("/")) {
    pathPrefix += "/"
  }

  return pathPrefix + (relativePath ? relativePath + "/" : "") + toFileName
}