import {
  cancel,
  confirm,
  group,
  intro,
  outro,
  select,
  text
} from '@clack/prompts'
import fs from 'fs-extra'
import template from 'lodash.template'
import path from 'node:path'
import process from 'node:process'
import { fileURLToPath } from 'node:url'
import c from 'picocolors'
import { slash } from '../shared'

export enum ScaffoldThemeType {
  Default = 'default theme',
  DefaultCustom = 'default theme + customization',
  Custom = 'custom theme'
}

export interface ScaffoldOptions {
  root?: string
  srcDir?: string
  title?: string
  description?: string
  theme?: ScaffoldThemeType
  useTs?: boolean
  injectNpmScripts?: boolean
  addNpmScriptsPrefix?: boolean
  npmScriptsPrefix?: string
}

const getPackageManger = () => {
  const name = process.env?.npm_config_user_agent || 'npm'
  return name.split('/')[0]
}

export async function init(root?: string) {
  intro(c.bold(c.cyan('Welcome to VitePress!')))

  const options = await group(
    {
      root: async () => {
        if (root) return root

        return text({
          message: 'Where should VitePress initialize the config?',
          initialValue: './',
          defaultValue: './',
          validate(value) {
            const cwd = slash(process.cwd())
            const dir = slash(value as string)

            const cwdRE = new RegExp(
              `^${dir.endsWith('/') ? `${cwd}/` : cwd}`,
              'u'
            )
            // If give absolute path, use that path instead
            const absolutePath =
              (process.platform === 'win32' && /^[A-Z]:/i.test(dir)) ||
              /^\//.test(dir)
                ? dir
                : path.join(cwd, dir)

            return !cwdRE.test(absolutePath)
              ? 'Please init your config inside this directory.'
              : undefined
          }
        })
      },

      srcDir: async ({ results }: any) => {
        return text({
          message: 'Where should VitePress look for your markdown files?',
          initialValue: results.root,
          defaultValue: results.root
        })
      },

      title: async () => {
        return text({
          message: 'Site title:',
          placeholder: 'My Awesome Project',
          defaultValue: 'My Awesome Project'
        })
      },

      description: async () => {
        return text({
          message: 'Site description:',
          placeholder: 'A VitePress Site',
          defaultValue: 'A VitePress Site'
        })
      },

      theme: async () => {
        return select({
          message: 'Theme:',
          options: [
            {
              value: ScaffoldThemeType.Default,
              label: 'Default Theme',
              hint: 'Out of the box, good-looking docs'
            },
            {
              value: ScaffoldThemeType.DefaultCustom,
              label: 'Default Theme + Customization',
              hint: 'Add custom CSS and layout slots'
            },
            {
              value: ScaffoldThemeType.Custom,
              label: 'Custom Theme',
              hint: 'Build your own or use external'
            }
          ]
        })
      },

      useTs: async () => {
        return confirm({
          message: 'Use TypeScript for config and theme files?'
        })
      },

      injectNpmScripts: async () => {
        return confirm({
          message: 'Add VitePress npm scripts to package.json?'
        })
      },

      addNpmScriptsPrefix: async ({ results }: any) => {
        if (!results.injectNpmScripts) return false

        return confirm({
          message: 'Add a prefix for VitePress npm scripts?'
        })
      },

      npmScriptsPrefix: async ({ results }: any) => {
        if (!results.addNpmScriptsPrefix) return 'docs'

        return text({
          message: 'Prefix for VitePress npm scripts:',
          placeholder: 'docs',
          defaultValue: 'docs'
        })
      }
    },
    {
      onCancel: () => {
        cancel('Cancelled.')
        process.exit(0)
      }
    }
  )

  outro(scaffold(options))
}

export function scaffold({
  root: root_ = './',
  srcDir: srcDir_ = root_,
  title = 'My Awesome Project',
  description = 'A VitePress Site',
  theme = ScaffoldThemeType.Default,
  useTs = true,
  injectNpmScripts = true,
  addNpmScriptsPrefix = true,
  npmScriptsPrefix = 'docs'
}: ScaffoldOptions) {
  const resolvedRoot = path.resolve(root_)
  const root = path.relative(process.cwd(), resolvedRoot)

  const resolvedSrcDir = path.resolve(srcDir_)
  const srcDir = path.relative(resolvedRoot, resolvedSrcDir)

  const templateDir = path.resolve(
    path.dirname(fileURLToPath(import.meta.url)),
    '../../template'
  )

  const data = {
    srcDir: srcDir ? JSON.stringify(srcDir) : undefined, // omit if default
    title: JSON.stringify(title),
    description: JSON.stringify(description),
    useTs,
    defaultTheme:
      theme === ScaffoldThemeType.Default ||
      theme === ScaffoldThemeType.DefaultCustom
  }

  const pkgPath = path.resolve('package.json')
  const userPkg = fs.existsSync(pkgPath)
    ? JSON.parse(fs.readFileSync(pkgPath, 'utf-8'))
    : {}

  const useMjs = userPkg.type !== 'module'

  const renderFile = (file: string) => {
    const filePath = path.resolve(templateDir, file)
    let targetPath = path.resolve(resolvedRoot, file)

    if (useMjs && file === '.vitepress/config.js') {
      targetPath = targetPath.replace(/\.js$/, '.mjs')
    }
    if (useTs) {
      targetPath = targetPath.replace(/\.(m?)js$/, '.$1ts')
    }
    if (file.endsWith('.md')) {
      targetPath = path.resolve(resolvedSrcDir, file)
    }

    const content = fs.readFileSync(filePath, 'utf-8')
    const compiled = template(content)(data)

    fs.outputFileSync(targetPath, compiled)
  }

  const filesToScaffold = [
    'index.md',
    'api-examples.md',
    'markdown-examples.md',
    '.vitepress/config.js'
  ]

  if (theme === ScaffoldThemeType.DefaultCustom) {
    filesToScaffold.push(
      '.vitepress/theme/index.js',
      '.vitepress/theme/style.css'
    )
  } else if (theme === ScaffoldThemeType.Custom) {
    filesToScaffold.push(
      '.vitepress/theme/index.js',
      '.vitepress/theme/style.css',
      '.vitepress/theme/Layout.vue'
    )
  }

  for (const file of filesToScaffold) {
    renderFile(file)
  }

  const tips = []

  const gitignorePrefix = root ? `${slash(root)}/.vitepress` : '.vitepress'
  if (fs.existsSync('.git')) {
    tips.push(
      `Make sure to add ${c.cyan(`${gitignorePrefix}/dist`)} and ${c.cyan(`${gitignorePrefix}/cache`)} to your ${c.cyan(`.gitignore`)} file.`
    )
  }

  if (
    theme !== ScaffoldThemeType.Default &&
    !userPkg.dependencies?.['vue'] &&
    !userPkg.devDependencies?.['vue']
  ) {
    tips.push(
      `Since you've chosen to customize the theme, you should also explicitly install ${c.cyan(`vue`)} as a dev dependency.`
    )
  }

  const tip = tips.length ? c.yellow([`\n\nTips:`, ...tips].join('\n- ')) : ``
  const dir = root ? ' ' + root : ''
  const pm = getPackageManger()

  if (injectNpmScripts) {
    const scripts: Record<string, string> = {}
    const prefix = addNpmScriptsPrefix ? `${npmScriptsPrefix}:` : ''

    scripts[`${prefix}dev`] = `vitepress dev${dir}`
    scripts[`${prefix}build`] = `vitepress build${dir}`
    scripts[`${prefix}preview`] = `vitepress preview${dir}`

    Object.assign(userPkg.scripts || (userPkg.scripts = {}), scripts)
    fs.writeFileSync(pkgPath, JSON.stringify(userPkg, null, 2))

    return `Done! Now run ${c.cyan(`${pm} run ${prefix}dev`)} and start writing.${tip}`
  } else {
    return `You're all set! Now run ${c.cyan(`${pm === 'npm' ? 'npx' : pm} vitepress dev${dir}`)} and start writing.${tip}`
  }
}