/*
 * 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 { createHash } from "crypto"
import * as fs from "fs/promises"
import { minify as minhtml } from "html-minifier"
import * as path from "path"
import { EMPTY, concat, defer, from, merge, of } from "rxjs"
import {
  concatMap,
  map,
  mergeMap,
  switchMap,
  toArray
} from "rxjs/operators"
import {
  extendDefaultPlugins,
  optimize
} from "svgo"

import { copy, copyAll } from "./copy"
import { base, cachebust, resolve } from "./resolve"
import {
  transformScript,
  transformStyle
} from "./transform"

/* ----------------------------------------------------------------------------
 * Helper functions
 * ------------------------------------------------------------------------- */

/**
 * Replace file extension
 *
 * @param file - File
 * @param extension - New extension
 *
 * @returns File with new extension
 */
function ext(file: string, extension: string): string {
  return file.replace(path.extname(file), extension)
}

/**
 * Optimize SVG data
 *
 * This function will just pass-through non-SVG data, which makes the pipeline
 * much simpler, as we can reuse it for the license texts.
 *
 * @param data - SVG data
 *
 * @returns Minified SVG data
 */
function minsvg(data: string): string {
  const result = optimize(data, {
    plugins: extendDefaultPlugins([
      { name: "removeDimensions", active: true },
      { name: "removeViewBox", active: false }
    ])
  })
  return result.data || data
}

/* ----------------------------------------------------------------------------
 * Program
 * ------------------------------------------------------------------------- */

/* Copy all dependencies */
const dependencies$ = concat(

  /* Copy Material Design icons */
  ...["*.svg", "../LICENSE"]
    .map(pattern => copyAll(pattern, {
      src: "node_modules/@mdi/svg/svg",
      out: `${base}/.icons/material`,
      ...process.argv.includes("--optimize") && {
        transform: async data => minsvg(data)
      }
    })),

  /* Copy GitHub octicons */
  ...["*.svg", "../../LICENSE"]
    .map(pattern => copyAll(pattern, {
      src: "node_modules/@primer/octicons/build/svg",
      out: `${base}/.icons/octicons`,
      ...process.argv.includes("--optimize") && {
        transform: async data => minsvg(data)
      }
    })),

  /* Copy FontAwesome icons */
  ...["**/*.svg", "../LICENSE.txt"]
    .map(pattern => copyAll(pattern, {
      src: "node_modules/@fortawesome/fontawesome-free/svgs",
      out: `${base}/.icons/fontawesome`,
      ...process.argv.includes("--optimize") && {
        transform: async data => minsvg(data)
      }
    }))
)

/* Copy all assets */
const assets$ = concat(

  /* Copy icons, images and configurations */
  ...[".icons/*.svg", "assets/images/*", "**/*.{py,yml}"]
    .map(pattern => copyAll(pattern, {
      src: "src",
      out: base
    })),

  /* Copy and minify template files */
  copyAll("**/*.html", {
    src: "src",
    out: base,
    transform: async data => {
      const metadata = require("../package.json")
      const banner =
        "{#-\n" +
        "  This file was automatically generated - do not edit\n" +
        "-#}\n"

      /* Normalize line feeds and minify HTML */
      const html = data.replace(/\r\n/gm, "\n")
      return banner + minhtml(html, {
        collapseBooleanAttributes: true,
        includeAutoGeneratedTags: false,
        minifyCSS: true,
        minifyJS: true,
        removeComments: true,
        removeScriptTypeAttributes: true,
        removeStyleLinkTypeAttributes: true
      })

        /* Remove empty lines without collapsing everything */
        .replace(/^\s*[\r\n]/gm, "")

        /* Write theme version into template */
        .replace("$md-name$", metadata.name)
        .replace("$md-version$", metadata.version)
    }
  })
)

/* Transform stylesheets with SASS and PostCSS */
const stylesheets$ = resolve("**/[!_]*.scss", { cwd: "src" })
  .pipe(
    concatMap(file => transformStyle({
      src: `src/${file}`,
      out: ext(`${base}/${file}`, ".css")
    }))
  )

/* Transform stylesheets with SASS and PostCSS */
const javascripts$ = resolve("**/{bundle,search}.ts", { cwd: "src" })
  .pipe(
    concatMap(file => transformScript({
      src: `src/${file}`,
      out: ext(`${base}/${file}`, ".js")
    }))
  )

/* Add content hashes to assets and replace occurrences */
const manifest$ = defer(() => process.argv.includes("--optimize")
  ? resolve("**/*.{css,js}", { cwd: base })
  : EMPTY
)
  .pipe(
    concatMap(file => from(fs.readFile(`${base}/${file}`, "utf8"))
      .pipe(
        map(data => createHash("sha256").update(data).digest("hex")),
        switchMap(hash => of(`${file}`, `${file}.map`)
          .pipe(
            concatMap(part => cachebust(part, hash, { cwd: base }))
          )
        )
      )
    ),
    toArray(),
    map(tuples => new Map(tuples)),
    mergeMap(manifest => concat(

      // TODO: split this into two. manifest + cachebust!
      ...["base.html", "overrides/main.html"]
        .map(file => copy({
          src: `${base}/${file}`,
          out: `${base}/${file}`,
          transform: async data => [...manifest.entries()]
            .reduce((content, [key, value]) => content
              .replace(
                new RegExp(`('|")${key}\\1`, "g"),
                `$1${value}$1`
              ),
              data
            )
        })),

        // TODO: interate this into the actual compilation...
        ...[...manifest.keys()]
          .filter(file => !file.endsWith(".map"))
          .map(file => copy({
            src: `${base}/${manifest.get(file)!}`,
            out: `${base}/${manifest.get(file)!}`,
            transform: async data => data.replace(
              path.basename(file),
              path.basename(manifest.get(file)!),
            )
          }))
    ))
  )

/* Copy Lunr.js search stemmers and segmenter */
const stemmers$ = ["min/*.js", "tinyseg.js"]
  .map(pattern => copyAll(pattern, {
    src: "node_modules/lunr-languages",
    out: `${base}/assets/javascripts/lunr`
  }))

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

/* Put everything together */
concat(
  dependencies$,
  merge(
    assets$,
    stylesheets$,
    javascripts$
  ),
  manifest$,
  stemmers$
)
  .subscribe()
  // .subscribe(console.log)