import type { CloudProvider, Region } from 'shared-data'
import { AWS_REGIONS } from 'shared-data'
import { SMART_REGION_TO_EXACT_REGION_MAP } from 'shared-data/regions'

import type { OrganizationAvailableRegionsData } from '@/data/organizations/organization-available-regions-query'
import {
  DesiredInstanceSize,
  instanceSizeSpecs,
  PostgresEngine,
  ReleaseChannel,
} from '@/data/projects/new-project.constants'

export function smartRegionToExactRegion(smartOrExactRegion: string) {
  return SMART_REGION_TO_EXACT_REGION_MAP.get(smartOrExactRegion) ?? smartOrExactRegion
}

export function getAvailableRegions(
  cloudProvider: CloudProvider,
  environment = process.env.NEXT_PUBLIC_ENVIRONMENT
): Region {
  switch (cloudProvider) {
    case 'AWS':
    case 'AWS_K8S':
      return AWS_REGIONS
    case 'AWS_NIMBUS':
      if (environment !== 'prod') {
        // Only allow Southeast Asia for Nimbus (local/staging)
        return {
          SOUTHEAST_ASIA: AWS_REGIONS.SOUTHEAST_ASIA,
        }
      }

      // Only allow US East for Nimbus (prod)
      return {
        EAST_US: AWS_REGIONS.EAST_US,
      }
    default:
      throw new Error('Invalid cloud provider')
  }
}

type ResolveDefaultDbRegionArgs = {
  cloudProvider: CloudProvider
  isHighAvailabilityRestricted: boolean
  highAvailabilityRegionName: string | undefined
  isSmartRegionEnabled: boolean
  recommendedSmartRegion: string | undefined
  autoDefaultRegion: string | undefined
  fixedDefaultRegion: string
  environment?: string
}

export function resolveDefaultDbRegion({
  cloudProvider,
  isHighAvailabilityRestricted,
  highAvailabilityRegionName,
  isSmartRegionEnabled,
  recommendedSmartRegion,
  autoDefaultRegion,
  fixedDefaultRegion,
  environment = process.env.NEXT_PUBLIC_ENVIRONMENT,
}: ResolveDefaultDbRegionArgs): string | undefined {
  if (isHighAvailabilityRestricted) return highAvailabilityRegionName
  if (isSmartRegionEnabled) return recommendedSmartRegion

  // The geolocated default is only usable if the provider actually offers that region
  // (e.g. AWS_NIMBUS is restricted to a single region)
  const isAutoDefaultRegionAvailable = Object.entries(
    getAvailableRegions(cloudProvider, environment)
  ).some(([, region]) => region.displayName === autoDefaultRegion)

  return isAutoDefaultRegionAvailable && autoDefaultRegion !== undefined
    ? autoDefaultRegion
    : fixedDefaultRegion
}

/**
 * When launching new projects, they only get assigned a compute size once successfully launched,
 * this might assume wrong compute size, but only for projects being rapidly launched after one another on non-default compute sizes.
 *
 * Needs to be in the API in the future [kevin]
 */
export const monthlyInstancePrice = (instance: string | undefined): number => {
  return instanceSizeSpecs[instance as DesiredInstanceSize]?.priceMonthly || 10
}

export const instanceLabel = (instance: string | undefined): string => {
  return instanceSizeSpecs[instance as DesiredInstanceSize]?.label || 'Micro'
}

export const getHighAvailabilityRegionCode = (
  environment = process.env.NEXT_PUBLIC_ENVIRONMENT
) => {
  // Local dev stacks can run in any of the supported regions, so they're left unrestricted
  if (environment === 'prod') return 'us-east-1'
  if (environment === 'staging') return 'us-east-1'
  if (environment === 'local') return 'eu-central-1'
  return undefined
}

export const filterHighAvailabilityRegions = <T extends { code: string }>(
  regions: T[],
  highAvailability: boolean,
  environment = process.env.NEXT_PUBLIC_ENVIRONMENT
) => {
  const isLocal = environment === 'local'
  const regionCode = getHighAvailabilityRegionCode(environment)
  return highAvailability && !isLocal && regionCode !== undefined
    ? regions.filter((region) => region.code === regionCode)
    : regions
}

export type FreeTierGeneralRegionExperimentVariant = 'test' | 'control'

type GetFreeTierGeneralRegionExperimentVariantArgs = {
  isFreePlan: boolean
  smartRegionEnabled: boolean
  enrollmentFlag: boolean
  selectionFlag: boolean
  /** When true, another feature owns the region selector and the experiment is inactive */
  isOverridden?: boolean
}

/**
 * Org's arm in the freeTierGeneralRegionExperiment. The test arm only sees general regions.
 * Returns undefined when the org isn't enrolled, or when the experiment is overridden.
 */
export function getFreeTierGeneralRegionExperimentVariant({
  isFreePlan,
  smartRegionEnabled,
  enrollmentFlag,
  selectionFlag,
  isOverridden = false,
}: GetFreeTierGeneralRegionExperimentVariantArgs):
  | FreeTierGeneralRegionExperimentVariant
  | undefined {
  const isInExperiment =
    !isOverridden && isFreePlan && smartRegionEnabled && enrollmentFlag === true
  if (!isInExperiment) return undefined
  return selectionFlag === true ? 'test' : 'control'
}

export type AvailableRegions = NonNullable<OrganizationAvailableRegionsData>['all']

type GetRegionSelectionTypeArgs = {
  dbRegion: string | undefined
  availableRegions: AvailableRegions | undefined
  /** Whether the user ever touched the region field. Defaults to true for untracked callers. */
  isDbRegionDirty?: boolean
}

/**
 * How the submitted region was arrived at: the auto-assigned default left untouched ('auto'),
 * a smart group region picked by the user (e.g. Americas, 'general'), or an exact region picked
 * by the user (e.g. us-east-1, 'specific'). Returns undefined if dbRegion matches neither list,
 * regardless of whether the field was touched.
 */
export function getRegionSelectionType({
  dbRegion,
  availableRegions,
  isDbRegionDirty = true,
}: GetRegionSelectionTypeArgs): 'general' | 'auto' | 'specific' | undefined {
  if (!dbRegion || !availableRegions) return undefined
  const isGeneral = availableRegions.smartGroup.some((region) => region.name === dbRegion)
  const isSpecific = availableRegions.specific.some((region) => region.name === dbRegion)
  if (!isGeneral && !isSpecific) return undefined
  if (!isDbRegionDirty) return 'auto'
  return isGeneral ? 'general' : 'specific'
}

export type SpecificRegionsLinkVariant = 'test' | 'control'

type GetSpecificRegionsLinkVariantArgs = {
  isFreePlan: boolean
  smartRegionEnabled: boolean
  linkFlag: boolean
}

/**
 * Org's arm in the projectCreationSpecificRegionsLink experiment. Returns undefined when the
 * org isn't in the eligible population (paid plan, or smart regions disabled for the selected
 * cloud provider) — the link can never show for them regardless of the flag.
 */
export function getSpecificRegionsLinkVariant({
  isFreePlan,
  smartRegionEnabled,
  linkFlag,
}: GetSpecificRegionsLinkVariantArgs): SpecificRegionsLinkVariant | undefined {
  if (!isFreePlan || !smartRegionEnabled) return undefined
  return linkFlag === true ? 'test' : 'control'
}

export interface PostgresVersionDetails {
  postgresEngine?: Exclude<PostgresEngine, '13' | '14'>
  releaseChannel?: ReleaseChannel
}

export const extractPostgresVersionDetails = (value: string): PostgresVersionDetails => {
  if (!value) {
    return { postgresEngine: undefined, releaseChannel: undefined }
  }

  const [postgresEngine, releaseChannel] = value.split('|')
  return { postgresEngine, releaseChannel } as PostgresVersionDetails
}

/**
 * Picks the engine + release channel to submit on project creation. The selector's value is used
 * only when it matches the selected Postgres Type in Advanced Config. Otherwise, OrioleDB falls
 * back to the available OrioleDB image, and Postgres falls back to the API default
 */
export function resolvePostgresVersion({
  postgresVersionSelection,
  useOrioleDb,
  availableOrioleVersion,
}: {
  postgresVersionSelection: string
  useOrioleDb: boolean
  availableOrioleVersion?: {
    postgres_engine: Exclude<PostgresEngine, '13' | '14'>
    release_channel: ReleaseChannel
  }
}): PostgresVersionDetails {
  const selection = extractPostgresVersionDetails(postgresVersionSelection)
  const isSelectionOriole = !!selection.postgresEngine?.endsWith('oriole')

  if (useOrioleDb) {
    if (isSelectionOriole) return selection
    return {
      postgresEngine: availableOrioleVersion?.postgres_engine,
      releaseChannel: availableOrioleVersion?.release_channel,
    }
  }

  if (isSelectionOriole) return {}
  return selection
}