import type { Root, RootContent } from 'mdast'
import type { Plugin } from 'unified'
import type { Directives } from 'mdast-util-directive'
import type { Node, Paragraph as P } from 'mdast'
import { h as _h, type Properties } from 'hastscript'

/** Checks if a node is a directive. */
function isNodeDirective(node: Node): node is Directives {
  return (
    node.type === 'containerDirective' ||
    node.type === 'leafDirective' ||
    node.type === 'textDirective'
  )
}

/** From Astro Starlight: Function that generates an mdast HTML tree ready for conversion to HTML by rehype. */
function h(el: string, attrs: Properties = {}, children: any[] = []): P {
  const { properties, tagName } = _h(el, attrs)
  return {
    children: children.filter((child) => !!child),
    data: { hName: tagName, hProperties: properties },
    type: 'paragraph',
  }
}

const DIRECTIVE_NAME = 'github'
const USER_AGENT = 'nodejs'
// 'Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:137.0) Gecko/20100101 Firefox/137.0',

export const remarkGithubCard: Plugin<[], Root> = () => async (tree) => {
  tree.children = await Promise.all(
    tree.children.map(async (node): Promise<RootContent> => {
      if (!isNodeDirective(node)) return node

      // We only want a leaf directive named DIRECTIVE_NAME
      if (node.type !== 'leafDirective' || node.name !== DIRECTIVE_NAME) return node

      let repoName = node.attributes?.repo ?? node.attributes?.user ?? null
      if (!repoName) return node // Leave the directive as-is if no repo is provided

      repoName = repoName.endsWith('/') ? repoName.slice(0, -1) : repoName // Remove trailing slash
      repoName = repoName.startsWith('https://github.com/')
        ? repoName.replace('https://github.com/', '')
        : repoName // Remove leading URL

      const repoParts = repoName.split('/')
      const realUrl = `https://github.com/${repoName}`

      // If its a repo link
      if (repoParts.length > 1) {
        const res = await fetch(`https://api.github.com/repos/${repoName}`, {
          headers: {
            'User-Agent': USER_AGENT,
          },
        })
        if (!res || res.status !== 200) {
          throw new Error(`Fetching GitHub repo data for "${repoName}" failed`)
        }
        const data = await res.json()
        const description = data.description
          ? data.description.replace(/:[a-zA-Z0-9_]+:/g, '')
          : undefined
        const backgroundImage = data.owner?.avatar_url
        const language = data.language
        const forks = Intl.NumberFormat(undefined, {
          notation: 'compact',
          maximumFractionDigits: 1,
        })
          .format(data.forks)
          .replaceAll('\u202f', '')
        const stars = Intl.NumberFormat(undefined, {
          notation: 'compact',
          maximumFractionDigits: 1,
        })
          .format(data.stargazers_count)
          .replaceAll('\u202f', '')
        const license = data.license?.spdx_id

        return h('div', { class: 'github-card' }, [
          h('div', { class: 'gh-title' }, [
            h('span', {
              class: 'gh-avatar',
              style: `background-image: url('${backgroundImage}')`,
            }),
            h('a', { class: 'gh-text', href: realUrl }, [
              { type: 'text', value: `${repoParts[0]}/${repoParts[1]}` },
            ]),
            h('span', { class: 'gh-icon' }),
          ]),
          description &&
            h('div', { class: 'gh-description' }, [
              {
                type: 'text',
                value: description,
              },
            ]),
          h('div', { class: 'gh-chips' }, [
            h('span', { class: 'gh-stars' }, [{ type: 'text', value: stars }]),
            h('span', { class: 'gh-forks' }, [{ type: 'text', value: forks }]),
            license &&
              h('span', { class: 'gh-license' }, [{ type: 'text', value: license }]),
            language &&
              h('span', { class: 'gh-language' }, [{ type: 'text', value: language }]),
          ]),
        ])
      }

      // If its a user link
      else if (repoParts.length === 1) {
        const res = await fetch(`https://api.github.com/users/${repoName}`, {
          headers: {
            'User-Agent': USER_AGENT,
          },
        })
        if (!res || res.status !== 200) {
          throw new Error(`Fetching GitHub user data for "${repoName}" failed`)
        }
        const data = await res.json()
        const backgroundImage = data.avatar_url
        const followers = Intl.NumberFormat(undefined, {
          notation: 'compact',
          maximumFractionDigits: 1,
        })
          .format(data.followers)
          .replaceAll('\u202f', '')
        const repositories = Intl.NumberFormat(undefined, {
          notation: 'compact',
          maximumFractionDigits: 1,
        })
          .format(data.public_repos)
          .replaceAll('\u202f', '')
        const region = data.location

        return h('div', { class: 'github-card' }, [
          h('div', { class: 'gh-title' }, [
            h('span', {
              class: 'gh-avatar',
              style: `background-image: url('${backgroundImage}')`,
            }),
            h('a', { class: 'gh-text', href: realUrl }, [
              { type: 'text', value: repoParts[0] },
            ]),
            h('span', { class: 'gh-icon' }),
          ]),
          h('div', { class: 'gh-chips' }, [
            h('span', { class: 'gh-followers' }, [{ type: 'text', value: followers }]),
            h('span', { class: 'gh-repositories' }, [
              { type: 'text', value: repositories },
            ]),
            region &&
              h('span', { class: 'gh-region' }, [{ type: 'text', value: region }]),
          ]),
        ])
      }

      return node
    }),
  )
}