/* eslint suggest-no-throw/suggest-no-throw: 0 */
import * as vscode from 'vscode'
import * as os from 'os'
import type { Config } from './config'
import { log, isValidExecutable } from './util'
import type { PersistentState } from './persistent_state'
import { exec } from 'child_process'

export async function bootstrap(
  context: vscode.ExtensionContext,
  config: Config,
  state: PersistentState
): Promise<string> {
  const path = await getServer(context, config, state)
  if (!path) {
    throw new Error(
      'KittyCAD Language Server is not available. ' +
        'Please, ensure its [proper installation](https://github.com/kittycad/kcl-lsp).'
    )
  }

  log.info('Using server binary at', path)

  if (!isValidExecutable(path)) {
    if (config.serverPath) {
      throw new Error(`Failed to execute ${path} --version. \`config.server.path\` or \`config.serverPath\` has been set explicitly.\
            Consider removing this config or making a valid server binary available at that path.`)
    } else {
      throw new Error(`Failed to execute ${path} --version`)
    }
  }

  return path
}
async function getServer(
  context: vscode.ExtensionContext,
  config: Config,
  state: PersistentState
): Promise<string | undefined> {
  const explicitPath =
    process.env['__KCL_LSP_SERVER_DEBUG'] ?? config.serverPath
  if (explicitPath) {
    if (explicitPath.startsWith('~/')) {
      return os.homedir() + explicitPath.slice('~'.length)
    }
    return explicitPath
  }
  if (config.package.releaseTag === null) return 'kcl-language-server'

  const ext = process.platform === 'win32' ? '.exe' : ''
  const bundled = vscode.Uri.joinPath(
    context.extensionUri,
    'server',
    `kcl-language-server${ext}`
  )
  log.info('Checking if bundled server exists at', bundled)
  const bundledExists = await vscode.workspace.fs.stat(bundled).then(
    () => true,
    () => false
  )
  log.info('Bundled server exists:', bundledExists)
  if (bundledExists) {
    let server = bundled
    if (await isNixOs()) {
      await vscode.workspace.fs.createDirectory(config.globalStorageUri).then()
      const dest = vscode.Uri.joinPath(
        config.globalStorageUri,
        `kcl-language-server${ext}`
      )
      let exists = await vscode.workspace.fs.stat(dest).then(
        () => true,
        () => false
      )
      if (exists && config.package.version !== state.serverVersion) {
        log.info(
          'Server version changed, removing old server binary',
          config.package.version,
          state.serverVersion
        )
        await vscode.workspace.fs.delete(dest)
        exists = false
      }
      if (!exists) {
        await vscode.workspace.fs.copy(bundled, dest)
        await patchelf(dest)
      }
      server = dest
    }

    await state.updateServerVersion(config.package.version)
    return server.fsPath
  }

  await state.updateServerVersion(undefined)
  await vscode.window.showErrorMessage(
    "Unfortunately we don't ship binaries for your platform yet. " +
      'You need to manually clone the kcl-lsp repository and ' +
      'run `cargo install` to build the language server from sources. ' +
      'If you feel that your platform should be supported, please create an issue ' +
      'about that [here](https://github.com/kittycad/kcl-lsp/issues) and we ' +
      'will consider it.'
  )
  return undefined
}

async function isNixOs(): Promise<boolean> {
  try {
    const contents = (
      await vscode.workspace.fs.readFile(vscode.Uri.file('/etc/os-release'))
    ).toString()
    const idString =
      contents.split('\n').find((a) => a.startsWith('ID=')) || 'ID=linux'
    return idString.indexOf('nixos') !== -1
  } catch {
    return false
  }
}

async function patchelf(dest: vscode.Uri): Promise<void> {
  await vscode.window.withProgress(
    {
      location: vscode.ProgressLocation.Notification,
      title: 'Patching kcl-language-server for NixOS',
    },
    async (progress, _) => {
      const expression = `
            {srcStr, pkgs ? import <nixpkgs> {}}:
                pkgs.stdenv.mkDerivation {
                    name = "kcl-language-server";
                    src = /. + srcStr;
                    phases = [ "installPhase" "fixupPhase" ];
                    installPhase = "cp $src $out";
                    fixupPhase = ''
                    chmod 755 $out
                    patchelf --set-interpreter "$(cat $NIX_CC/nix-support/dynamic-linker)" $out
                    '';
                }
            `
      const origFile = vscode.Uri.file(dest.fsPath + '-orig')
      await vscode.workspace.fs.rename(dest, origFile, { overwrite: true })
      try {
        progress.report({ message: 'Patching executable', increment: 20 })
        await new Promise((resolve, reject) => {
          const handle = exec(
            `nix-build -E - --argstr srcStr '${origFile.fsPath}' -o '${dest.fsPath}'`,
            (err, stdout, stderr) => {
              if (err != null) {
                reject(Error(stderr))
              } else {
                resolve(stdout)
              }
            }
          )
          handle.stdin?.write(expression)
          handle.stdin?.end()
        })
      } finally {
        await vscode.workspace.fs.delete(origFile)
      }
    }
  )
}