/**
  Copyright (c) taskylizard. All rights reserved.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

  http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
*/
import { mkdir, readFile, writeFile } from 'node:fs/promises'
import { dirname, resolve } from 'node:path'
import { fileURLToPath } from 'node:url'
import { createContentLoader } from 'vitepress'
import type { ContentData, SiteConfig } from 'vitepress'
import { type SatoriOptions, satoriVue } from 'x-satori/vue'
import { renderAsync } from '@resvg/resvg-js'
import consola from 'consola'
import { headers } from '../transformer/constants'

const __dirname = dirname(fileURLToPath(import.meta.url))
const __fonts = resolve(__dirname, '../fonts')

export async function generateImages(config: SiteConfig): Promise<void> {
  const pages = await createContentLoader('**/*.md', { excerpt: true }).load()
  const template = await readFile(resolve(__dirname, './Template.vue'), 'utf-8')

  const fonts: SatoriOptions['fonts'] = [
    {
      name: 'Inter',
      data: await readFile(resolve(__fonts, 'Inter-Regular.otf')),
      weight: 400,
      style: 'normal'
    },
    {
      name: 'Inter',
      data: await readFile(resolve(__fonts, 'Inter-Medium.otf')),
      weight: 500,
      style: 'normal'
    },
    {
      name: 'Inter',
      data: await readFile(resolve(__fonts, 'Inter-SemiBold.otf')),
      weight: 600,
      style: 'normal'
    },
    {
      name: 'Inter',
      data: await readFile(resolve(__fonts, 'Inter-Bold.otf')),
      weight: 700,
      style: 'normal'
    }
  ]

  for (const page of pages) {
    await generateImage({
      page,
      template,
      outDir: config.outDir,
      fonts
    })
  }
  return consola.info('Generated opengraph images.')
}

interface GenerateImagesOptions {
  page: ContentData
  template: string
  outDir: string
  fonts: SatoriOptions['fonts']
}

async function generateImage({
  page,
  template,
  outDir,
  fonts
}: GenerateImagesOptions): Promise<void> {
  const { frontmatter, url } = page

  const _page = getPage(url)
  const title =
    frontmatter.layout === 'home'
      ? (frontmatter.hero.name ?? frontmatter.title)
      : frontmatter.title
        ? frontmatter.title
        : _page?.title

  const description =
    frontmatter.layout === 'home'
      ? (frontmatter.hero.tagline ?? frontmatter.description)
      : frontmatter.description
        ? frontmatter.description
        : _page?.description

  // consola.info(url, title, description)
  const options: SatoriOptions = {
    width: 1200,
    height: 628,
    fonts,
    props: {
      title,
      description
    }
  }

  const svg = await satoriVue(options, template)

  const render = await renderAsync(svg)

  const outputFolder = resolve(outDir, url.slice(1), '__og_image__')
  const outputFile = resolve(outputFolder, 'og.png')

  await mkdir(outputFolder, { recursive: true })

  await writeFile(outputFile, render.asPng())
}

function getPage(page: string) {
  // Get the page name
  const pageName = `${page}.md`.slice(1).split('/').at(-1)

  // Find the header
  // TODO: This is a hacky way to find the header
  const header = Object.entries(headers).find(([key]) => key === pageName)
  if (!header) return

  const { title, description } = header[1]

  return {
    title,
    description
  }
}