import { FileType, ProjectPlugin, ProjectPluginStructure } from '@teleporthq/teleport-types'
import { TRACKER_SOURCE } from './tracker-source'
import { buildTrackerComponentSource } from './tracker-component'
import { buildExperimentHeadSnippet, collectExperimentIds } from './experiments'
import { injectSiblingIntoApp } from '../app-sibling-injection'
import { loadsGoogleTag } from './google-consent-mode'

const ENV_URL_KEY = 'NEXT_PUBLIC_TELEPORT_ANALYTICS_URL'
const ENV_PUBLIC_KEY = 'NEXT_PUBLIC_TELEPORT_ANALYTICS_KEY'
// Server-only (no NEXT_PUBLIC_ prefix): what the site's server segments
// present when they report a purchase or a booking. Minted by the platform at
// deploy time from the public key; never reaches the browser bundle.
const ENV_SERVER_KEY = 'TELEPORT_ANALYTICS_SERVER_KEY'
const TELEPORT_SECRETS_PREFIX = 'teleporthq.secrets.'

// Growth visitor analytics. When `uidl.analytics.enabled` is set (paid plan +
// analytics on at publish time), the published project ships a tiny
// self-contained first-party tracker — no npm dependency — wired to the
// pages-router navigation events. The real env values are substituted at
// deploy time by the platform (replaceSecretsFromEnvFile).
//
// ⛔ It also ships when the merchant configured GA4 or Tag Manager and left OUR
// analytics off. The commerce funnel is fired from serialized workflow handlers
// that can only reach a global, and `window.tpTrackCommerce` is published by
// this component — so without it a store with a GTM container gets NO
// add_to_cart, begin_checkout or purchase events at all, which is precisely the
// "run GA4/Ads out of the box" the funnel exists for. Emitting it is inert for
// our own beacons: `isTrackingPossible()` refuses to send without the analytics
// URL and key, and those env placeholders are deliberately NOT written on this
// branch — a project whose analytics is off must not have them resolved at
// deploy and quietly start reporting.
export class NextAnalyticsProjectPlugin implements ProjectPlugin {
  async runBefore(structure: ProjectPluginStructure): Promise<ProjectPluginStructure> {
    // A/B tests: the arm is picked in <head>, before the body is parsed, so a
    // page with an experiment never shows both variants. Independent of
    // analytics being on — the page must still show ONE variant; only the
    // counting needs the tracker. Added here (before the document is built)
    // because `_document` reads `customCode.head` during generation.
    const { uidl } = structure
    const snippet = buildExperimentHeadSnippet(collectExperimentIds(uidl))
    if (snippet) {
      const customCode = uidl.globals.customCode ?? {}
      uidl.globals.customCode = { ...customCode, head: `${snippet}${customCode.head ?? ''}` }
    }
    return structure
  }

  async runAfter(structure: ProjectPluginStructure): Promise<ProjectPluginStructure> {
    const { uidl, files } = structure

    const teleportAnalyticsEnabled = !!uidl.analytics?.enabled
    if (!teleportAnalyticsEnabled && !loadsGoogleTag(uidl)) {
      return structure
    }

    files.set('teleport-analytics-lib', {
      path: ['lib'],
      files: [
        {
          name: 'teleport-analytics',
          fileType: FileType.JS,
          content: TRACKER_SOURCE,
        },
      ],
    })

    files.set('teleport-analytics-tracker', {
      path: ['components', 'analytics'],
      files: [
        {
          name: 'AnalyticsTracker',
          fileType: FileType.JS,
          content: buildTrackerComponentSource(uidl.analytics?.disabledPaths),
        },
      ],
    })

    if (teleportAnalyticsEnabled) {
      this.addEnvVariables(uidl)
    }
    injectSiblingIntoApp(structure, {
      componentName: 'AnalyticsTracker',
      importStatement: `import AnalyticsTracker from '../components/analytics/AnalyticsTracker';\n`,
    })

    return structure
  }

  private addEnvVariables(uidl: ProjectPluginStructure['uidl']): void {
    if (!uidl.globals.env) {
      uidl.globals.env = {}
    }

    // Placeholder values resolved against project secrets at deploy time;
    // the GUI mapper usually sets these already — only fill the gaps.
    if (!uidl.globals.env[ENV_URL_KEY]) {
      uidl.globals.env[ENV_URL_KEY] = `${TELEPORT_SECRETS_PREFIX}${ENV_URL_KEY}`
    }
    if (!uidl.globals.env[ENV_PUBLIC_KEY]) {
      uidl.globals.env[ENV_PUBLIC_KEY] = `${TELEPORT_SECRETS_PREFIX}${ENV_PUBLIC_KEY}`
    }
    if (!uidl.globals.env[ENV_SERVER_KEY]) {
      uidl.globals.env[ENV_SERVER_KEY] = `${TELEPORT_SECRETS_PREFIX}${ENV_SERVER_KEY}`
    }
  }
}