import type { V0_1ToV0_2UpdateConfig } from './index'
import type { BaseAgent } from '../../../../agent/BaseAgent'
import type { MediationRecord } from '../../../../modules/routing'

import { MediationRepository, MediationRole } from '../../../../modules/routing'

/**
 * Migrates the {@link MediationRecord} to 0.2 compatible format. It fetches all records from storage
 * and applies the needed updates to the records. After a record has been transformed, it is updated
 * in storage and the next record will be transformed.
 *
 * The following transformations are applied:
 *  - {@link updateMediationRole}
 */
export async function migrateMediationRecordToV0_2<Agent extends BaseAgent>(
  agent: Agent,
  upgradeConfig: V0_1ToV0_2UpdateConfig
) {
  agent.config.logger.info('Migrating mediation records to storage version 0.2')
  const mediationRepository = agent.dependencyManager.resolve(MediationRepository)

  agent.config.logger.debug(`Fetching all mediation records from storage`)
  const allMediationRecords = await mediationRepository.getAll(agent.context)

  agent.config.logger.debug(`Found a total of ${allMediationRecords.length} mediation records to update.`)
  for (const mediationRecord of allMediationRecords) {
    agent.config.logger.debug(`Migrating mediation record with id ${mediationRecord.id} to storage version 0.2`)

    await updateMediationRole(agent, mediationRecord, upgradeConfig)

    await mediationRepository.update(agent.context, mediationRecord)

    agent.config.logger.debug(
      `Successfully migrated mediation record with id ${mediationRecord.id} to storage version 0.2`
    )
  }
}

/**
 * The role in the mediation record was always being set to {@link MediationRole.Mediator} for both mediators and recipients. This didn't cause any issues, but would return the wrong role for recipients.
 *
 * In 0.2 a check is added to make sure the role of a mediation record matches with actions (e.g. a recipient can't grant mediation), which means it will throw an error if the role is not set correctly.
 *
 * Because it's not always possible detect whether the role should actually be mediator or recipient, a number of configuration options are provided on how the role should be updated:
 *
 * - `allMediator`: The role is set to {@link MediationRole.Mediator} for both mediators and recipients
 * - `allRecipient`: The role is set to {@link MediationRole.Recipient} for both mediators and recipients
 * - `recipientIfEndpoint`: The role is set to {@link MediationRole.Recipient} if their is an `endpoint` configured on the record otherwise it is set to {@link MediationRole.Mediator}.
 *      The endpoint is not set when running as a mediator, so in theory this allows to determine the role of the record.
 *      There is one case where this could be problematic when the role should be recipient, if the mediation grant hasn't actually occurred (meaning the endpoint is not set).
 * - `doNotChange`: The role is not changed
 *
 * Most agents only act as either the role of mediator or recipient, in which case the `allMediator` or `allRecipient` configuration is the most appropriate. If your agent acts as both a recipient and mediator, the `recipientIfEndpoint` configuration is the most appropriate. The `doNotChange` options is not recommended and can lead to errors if the role is not set correctly.
 *
 */
export async function updateMediationRole<Agent extends BaseAgent>(
  agent: Agent,
  mediationRecord: MediationRecord,
  { mediationRoleUpdateStrategy }: V0_1ToV0_2UpdateConfig
) {
  agent.config.logger.debug(`Updating mediation record role using strategy '${mediationRoleUpdateStrategy}'`)

  switch (mediationRoleUpdateStrategy) {
    case 'allMediator':
      mediationRecord.role = MediationRole.Mediator
      break
    case 'allRecipient':
      mediationRecord.role = MediationRole.Recipient
      break
    case 'recipientIfEndpoint':
      if (mediationRecord.endpoint) {
        agent.config.logger.debug('Mediation record endpoint is set, setting mediation role to recipient')
        mediationRecord.role = MediationRole.Recipient
      } else {
        agent.config.logger.debug('Mediation record endpoint is not set, setting mediation role to mediator')
        mediationRecord.role = MediationRole.Mediator
      }
      break
    case 'doNotChange':
      break
  }
}