import { Injectable } from '@angular/core'
import { BehaviorSubject } from 'rxjs'

export type StartupStepStatus = 'pending' | 'in_progress' | 'done' | 'error'

/** A name/value pair shown under a startup step. */
export interface StartupStepDetail {
  name: string
  value: string
}

export interface StartupStep {
  label: string
  status: StartupStepStatus
  detail?: string
  /** Rendered as a grid under the label. */
  details?: StartupStepDetail[]
}

/**
 * Index of the `<sasjs>` tag dump within the startup steps.  It is appended
 * after the three startup checks so the indices the startup flow already drives
 * (sas.service / app.service) are unchanged.
 */
export const SASJS_TAG_STEP = 3

/**
 * Canonical spelling of the `<sasjs>` tag attributes.  HTML lower-cases attribute
 * names in the DOM, so they are mapped back for display.
 */
const TAG_ATTRIBUTE_NAMES: Record<string, string> = {
  serverurl: 'serverUrl',
  apploc: 'appLoc',
  servertype: 'serverType',
  loginmechanism: 'loginMechanism',
  admingroup: 'adminGroup',
  dcpath: 'dcPath',
  debug: 'debug',
  usecomputeapi: 'useComputeApi',
  runastask: 'runAsTask',
  contextname: 'contextName',
  hotlicencekey: 'hotLicenceKey'
}

/**
 * Reads the attributes of the `<sasjs>` tag for display in the startup checks.
 * Every attribute is shown - including ones the parser does not know about, so a
 * misspelt one is visible and a wrong value is exactly the misconfiguration this
 * dump exists to expose.
 */
export const getSasjsTagDetails = (element: Element): StartupStepDetail[] =>
  Array.from(element.attributes).map((attribute) => ({
    name: TAG_ATTRIBUTE_NAMES[attribute.name.toLowerCase()] || attribute.name,
    value: attribute.value || '(empty)'
  }))

@Injectable({ providedIn: 'root' })
export class StartupCheckService {
  private steps: StartupStep[] = [
    { label: 'Checking app location', status: 'pending' },
    { label: 'Checking Viya deploy', status: 'pending' },
    { label: 'Loading startup service', status: 'pending' },
    { label: 'SASjs tag', status: 'pending' }
  ]

  public steps$ = new BehaviorSubject<StartupStep[]>([...this.steps])

  public updateStep(index: number, status: StartupStepStatus, detail?: string) {
    if (index >= 0 && index < this.steps.length) {
      this.steps[index] = {
        ...this.steps[index],
        status,
        detail: detail ?? this.steps[index].detail
      }
      this.steps$.next([...this.steps])
    }
  }

  /** Shows the `<sasjs>` tag contents on the boot screen. */
  public setTagDetails(details: StartupStepDetail[]) {
    this.steps[SASJS_TAG_STEP] = {
      ...this.steps[SASJS_TAG_STEP],
      status: 'done',
      details
    }
    this.steps$.next([...this.steps])
  }

  public setSteps(steps: StartupStep[]) {
    this.steps = steps
    this.steps$.next([...this.steps])
  }
}