import path from 'path'
import fs from 'fs'
import { getSessionController } from './'
import {
  readFile,
  fileExists,
  createFile,
  moveFile,
  readFileBinary
} from '@sasjs/utils'
import { PreProgramVars, TreeNode } from '../../types'
import {
  extractHeaders,
  generateFileUploadSasCode,
  getTmpFilesFolderPath,
  HTTPHeaders,
  isDebugOn,
  sasJSCoreMacros
} from '../../utils'

export interface ExecutionVars {
  [key: string]: string | number | undefined
}

export interface ExecuteReturnRaw {
  httpHeaders: HTTPHeaders
  result: string | Buffer
}

export interface ExecuteReturnJson {
  httpHeaders: HTTPHeaders
  webout: string | Buffer
  log?: string
}

export class ExecutionController {
  async executeFile(
    programPath: string,
    preProgramVariables: PreProgramVars,
    vars: ExecutionVars,
    otherArgs?: any,
    returnJson?: boolean
  ) {
    if (!(await fileExists(programPath)))
      throw 'ExecutionController: SAS file does not exist.'

    const program = await readFile(programPath)

    return this.executeProgram(
      program,
      preProgramVariables,
      vars,
      otherArgs,
      returnJson
    )
  }

  async executeProgram(
    program: string,
    preProgramVariables: PreProgramVars,
    vars: ExecutionVars,
    otherArgs?: any,
    returnJson?: boolean
  ): Promise<ExecuteReturnRaw | ExecuteReturnJson> {
    const sessionController = getSessionController()

    const session = await sessionController.getSession()
    session.inUse = true
    session.consumed = true

    const logPath = path.join(session.path, 'log.log')
    const headersPath = path.join(session.path, 'stpsrv_header.txt')
    const weboutPath = path.join(session.path, 'webout.txt')
    const tokenFile = path.join(session.path, 'accessToken.txt')

    await createFile(weboutPath, '')
    await createFile(
      tokenFile,
      preProgramVariables?.accessToken ?? 'accessToken'
    )

    const varStatments = Object.keys(vars).reduce(
      (computed: string, key: string) =>
        `${computed}%let ${key}=${vars[key]};\n`,
      ''
    )

    const preProgramVarStatments = `
%let _sasjs_tokenfile=${tokenFile};
%let _sasjs_username=${preProgramVariables?.username};
%let _sasjs_userid=${preProgramVariables?.userId};
%let _sasjs_displayname=${preProgramVariables?.displayName};
%let _sasjs_apiserverurl=${preProgramVariables?.serverUrl};
%let _sasjs_apipath=/SASjsApi/stp/execute;
%let _metaperson=&_sasjs_displayname;
%let _metauser=&_sasjs_username;
%let sasjsprocessmode=Stored Program;
%let sasjs_stpsrv_header_loc=%sysfunc(pathname(work))/../stpsrv_header.txt;

%global SYSPROCESSMODE SYSTCPIPHOSTNAME SYSHOSTINFOLONG;
%macro _sasjs_server_init();
  %if "&SYSPROCESSMODE"="" %then %let SYSPROCESSMODE=&sasjsprocessmode;
  %if "&SYSTCPIPHOSTNAME"="" %then %let SYSTCPIPHOSTNAME=&_sasjs_apiserverurl;
%mend;
%_sasjs_server_init()
`

    program = `
options insert=(SASAUTOS="${sasJSCoreMacros}");

/* runtime vars */
${varStatments}
filename _webout "${weboutPath}" mod;

/* dynamic user-provided vars */
${preProgramVarStatments}

/* actual job code */
${program}`

    // if no files are uploaded filesNamesMap will be undefined
    if (otherArgs?.filesNamesMap) {
      const uploadSasCode = await generateFileUploadSasCode(
        otherArgs.filesNamesMap,
        session.path
      )

      //If sas code for the file is generated it will be appended to the top of sasCode
      if (uploadSasCode.length > 0) {
        program = `${uploadSasCode}` + program
      }
    }

    const codePath = path.join(session.path, 'code.sas')

    // Creating this file in a RUNNING session will break out
    // the autoexec loop and actually execute the program
    // but - given it will take several milliseconds to create
    // (which can mean SAS trying to run a partial program, or
    // failing due to file lock) we first create the file THEN
    // we rename it.
    await createFile(codePath + '.bkp', program)
    await moveFile(codePath + '.bkp', codePath)

    // we now need to poll the session status
    while (!session.completed) {
      await delay(50)
    }

    const log = (await fileExists(logPath)) ? await readFile(logPath) : ''
    const headersContent = (await fileExists(headersPath))
      ? await readFile(headersPath)
      : ''
    const httpHeaders: HTTPHeaders = extractHeaders(headersContent)
    const fileResponse: boolean =
      httpHeaders.hasOwnProperty('content-type') && !returnJson

    const webout = (await fileExists(weboutPath))
      ? fileResponse
        ? await readFileBinary(weboutPath)
        : await readFile(weboutPath)
      : ''

    // it should be deleted by scheduleSessionDestroy
    session.inUse = false

    if (returnJson) {
      return {
        httpHeaders,
        webout,
        log: isDebugOn(vars) || session.crashed ? log : undefined
      }
    }

    return {
      httpHeaders,
      result: fileResponse
        ? webout
        : isDebugOn(vars) || session.crashed
        ? `<html><body>${webout}<div style="text-align:left"><hr /><h2>SAS Log</h2><pre>${log}</pre></div></body></html>`
        : webout
    }
  }

  buildDirectoryTree() {
    const root: TreeNode = {
      name: 'files',
      relativePath: '',
      absolutePath: getTmpFilesFolderPath(),
      children: []
    }

    const stack = [root]

    while (stack.length) {
      const currentNode = stack.pop()

      if (currentNode) {
        const children = fs.readdirSync(currentNode.absolutePath)

        for (let child of children) {
          const absoluteChildPath = `${currentNode.absolutePath}/${child}`
          const relativeChildPath = `${currentNode.relativePath}/${child}`
          const childNode: TreeNode = {
            name: child,
            relativePath: relativeChildPath,
            absolutePath: absoluteChildPath,
            children: []
          }
          currentNode.children.push(childNode)

          if (fs.statSync(childNode.absolutePath).isDirectory()) {
            stack.push(childNode)
          }
        }
      }
    }

    return root
  }
}

const delay = (ms: number) => new Promise((resolve) => setTimeout(resolve, ms))