import { dirname, isAbsolute, relative } from 'node:path'
import { existsSync } from 'node:fs'
import { mkdir, readFile, writeFile as writeFile_ } from 'node:fs/promises'
import type { EasyComContext } from './context'
import { notNullish, slash } from '../utils'
import { ComponentInfo } from './types'

const multilineCommentsRE = /\/\*.*?\*\//gms
const singlelineCommentsRE = /\/\/.*$/gm

function extractImports(code: string) {
  return Object.fromEntries(
    Array.from(code.matchAll(/['"]?([^\s'"]+)['"]?\s*:\s*(.+?)[,;\n]/g)).map(
      (i) => [i[1], i[2]]
    )
  )
}

export function parseDeclaration(code: string): DeclarationImports | undefined {
  if (!code) return

  code = code.replace(multilineCommentsRE, '').replace(singlelineCommentsRE, '')

  const imports: DeclarationImports = {
    component: {},
  }
  const componentDeclaration =
    /export\s+interface\s+GlobalComponents\s*{(.*?)}/s.exec(code)?.[0]
  if (componentDeclaration)
    imports.component = extractImports(componentDeclaration)

  return imports
}

/**
 * Converts `ComponentInfo` to an array
 *
 * `[name, "typeof import(path)[importName]"]`
 */
function stringifyComponentInfo(
  filepath: string,
  { from: path, as: name, name: importName }: ComponentInfo
): [string, string] | undefined {
  if (!name) return undefined
  const related = isAbsolute(path)
    ? `./${relative(dirname(filepath), path)}`
    : path
  const entry = `typeof import('${slash(related)}')['${
    importName || 'default'
  }']`
  return [name, entry]
}

/**
 * Converts array of `ComponentInfo` to an import map
 *
 * `{ name: "typeof import(path)[importName]", ... }`
 */
export function stringifyComponentsInfo(
  filepath: string,
  components: ComponentInfo[]
): Record<string, string> {
  return Object.fromEntries(
    components
      .map((info) => stringifyComponentInfo(filepath, info))
      .filter(notNullish)
  )
}

export interface DeclarationImports {
  component: Record<string, string>
}

export function getDeclarationImports(
  ctx: EasyComContext,
  filepath: string
): DeclarationImports | undefined {
  const component = stringifyComponentsInfo(filepath, [
    ...Object.values(ctx.componentMap),
  ])

  if (Object.keys(component).length === 0) return

  return { component }
}

export function stringifyDeclarationImports(imports: Record<string, string>) {
  return Object.entries(imports)
    .sort(([a], [b]) => a.localeCompare(b))
    .map(([name, v]) => {
      if (!/^\w+$/.test(name)) name = `'${name}'`
      return `${name}: ${v}`
    })
}

export function getDeclaration(
  ctx: EasyComContext,
  filepath: string,
  originalImports?: DeclarationImports
) {
  const imports = getDeclarationImports(ctx, filepath)
  if (!imports) return

  const declarations = {
    component: stringifyDeclarationImports({
      ...originalImports?.component,
      ...imports.component,
    }),
  }

  const head = `export {}

declare module 'vue' {`

  let code = `/* eslint-disable */
/* prettier-ignore */
// @ts-nocheck
${head}`

  if (Object.keys(declarations.component).length > 0) {
    code += `
  export interface GlobalComponents {
    ${declarations.component.join('\n    ')}
  }`
  }
  code += '\n}\n'
  return code
}

async function writeFile(filePath: string, content: string) {
  await mkdir(dirname(filePath), { recursive: true })
  return await writeFile_(filePath, content, 'utf-8')
}

export async function writeDeclaration(
  ctx: EasyComContext,
  filepath: string,
  removeUnused = false
) {
  const originalContent = existsSync(filepath)
    ? await readFile(filepath, 'utf-8')
    : ''
  const originalImports = removeUnused
    ? undefined
    : parseDeclaration(originalContent)

  const code = getDeclaration(ctx, filepath, originalImports)
  if (!code) return

  if (code !== originalContent) await writeFile(filepath, code)
}