/*
 * Copyright (c) 2016-2021 Martin Donath <martin.donath@squidfunk.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

import * as chokidar from "chokidar"
import * as fs from "fs/promises"
import {
  EMPTY,
  Observable,
  from,
  fromEvent,
  identity,
  catchError,
  defer,
  mapTo,
  mergeWith,
  of,
  switchMap,
  tap
} from "rxjs"
import glob from "tiny-glob"

/* ----------------------------------------------------------------------------
 * Helper types
 * ------------------------------------------------------------------------- */

/**
 * Resolve options
 */
interface ResolveOptions {
  cwd: string                          /* Working directory */
  watch?: boolean                      /* Watch mode */
}

/**
 * Watch options
 */
interface WatchOptions {
  cwd: string                          /* Working directory */
}

/* ----------------------------------------------------------------------------
 * Data
 * ------------------------------------------------------------------------- */

/**
 * Base directory for compiled files
 */
export const base = "material"

/**
 * Cache to omit redundant writes
 */
export const cache = new Map<string, string>()

/* ----------------------------------------------------------------------------
 * Helper Ffunctions
 * ------------------------------------------------------------------------- */

/**
 * Return the current time
 *
 * @returns Time
 */
function now() {
  const date = new Date()
  return [
    `${date.getHours()}`.padStart(2, "0"),
    `${date.getMinutes()}`.padStart(2, "0"),
    `${date.getSeconds()}`.padStart(2, "0")
  ]
    .join(":")
}

/* ----------------------------------------------------------------------------
 * Functions
 * ------------------------------------------------------------------------- */

/**
 * Resolve a pattern
 *
 * @param pattern - Pattern
 * @param options - Options
 *
 * @returns File observable
 */
export function resolve(
  pattern: string, options?: ResolveOptions
): Observable<string> {
  return from(glob(pattern, options))
    .pipe(
      catchError(() => EMPTY),
      switchMap(files => from(files)),
      options?.watch
        ? mergeWith(watch(pattern, options))
        : identity
    )
}

/**
 * Watch all files matching the given pattern
 *
 * @param pattern - Pattern
 * @param options - Options
 *
 * @returns File observable
 */
export function watch(
  pattern: string, options: WatchOptions
): Observable<string> {
  return fromEvent(
    chokidar.watch(pattern, options),
    "change"
  ) as Observable<string>
}

/* ------------------------------------------------------------------------- */

/**
 * Recursively create the given directory
 *
 * @param directory - Directory
 *
 * @returns Directory observable
 */
export function mkdir(directory: string): Observable<string> {
  return defer(() => fs.mkdir(directory, { recursive: true }))
    .pipe(
      mapTo(directory)
    )
}

/**
 * Read a file
 *
 * @param file - File
 *
 * @returns File data observable
 */
export function read(file: string): Observable<string> {
  return defer(() => fs.readFile(file, "utf8"))
}


/**
 * Write a file, but only if the contents changed
 *
 * @param file - File
 * @param data - File data
 *
 * @returns File observable
 */
export function write(file: string, data: string): Observable<string> {
  let contents = cache.get(file)
  if (contents === data) {
    return of(file)
  } else {
    cache.set(file, data)
    return defer(() => fs.writeFile(file, data))
      .pipe(
        mapTo(file),
        process.argv.includes("--verbose")
          ? tap(file => console.log(`${now()} + ${file}`))
          : identity
      )
  }
}