module Registry.ResourcesAPI declares *

import "registry-service.aqua"
import "registry-api.aqua"
import "@fluencelabs/aqua-lib/builtin.aqua"

alias ResourceId: string
alias Error: string

const REPLICATION_FACTOR = 1
const CONSISTENCY_LEVEL = 1
const DEFAULT_TIMEOUT = 6000

func wait(successful: *bool, len: i16, timeout: u16) -> bool:
  status: *string
  waiting = (arr: *bool, s: *string):
    join arr[len - 1]
    s <<- "ok"

  waiting(successful, status)
  par status <- Peer.timeout(timeout, "timeout")

  result: *bool
  if status! == "ok":
    result <<- true
  else:
    result <<- false
  <- result!

func appendErrors(error1: *Error, error2: *Error):
  for e <- error2:
    error1 <<- e

func getResourceId(label: string, peer_id: string) -> ResourceId:
  resource_id <- Registry.get_key_id(label, peer_id)
  <- resource_id

-- Get peers closest to the resource_id's hash in Kademlia network
-- These peers are expected to store list of providers for this key
func getNeighbours(resource_id: ResourceId) -> []PeerId:
  k <- Op.string_to_b58(resource_id)
  nodes <- Kademlia.neighborhood(k, nil, nil)
  <- nodes

func getResource(resource_id: ResourceId) -> ?Key, *Error:
  nodes <- getNeighbours(resource_id)
  result: ?Key
  error: *Error

  resources: *Key
  successful: *bool
  for n <- nodes par:
    on n:
      try:
        t <- Peer.timestamp_sec()
        get_result <- Registry.get_key_metadata(resource_id, t)
        if get_result.success:
          resources <<- get_result.key
          successful <<- true
        else:
          e <- Op.concat_strings(get_result.error, " on ")
          error <- Op.concat_strings(e, n)

  success <- wait(successful, CONSISTENCY_LEVEL, DEFAULT_TIMEOUT)
  if success == false:
    error <<- "resource not found: timeout exceeded"
  else:
    merge_result <- Registry.merge_keys(resources)

    if merge_result.success:
      result <<- merge_result.key
    else:
      error <<- merge_result.error

  <- result, error

-- If this peer have set node_id as a provider for resource,
-- this call will prevent provider from renew
-- so that eventually it will disappear from the providers list
func removeNodeFromProviders(provider_node_id: PeerId, resource_id: ResourceId):
  on provider_node_id:
    t <- Peer.timestamp_sec()
    Registry.clear_host_record(resource_id, t)

-- Create a resource: register it on the closest peers
func createResource(label: string) -> ?ResourceId, *Error:
  t <- Peer.timestamp_sec()

  resource_id: ?ResourceId
  error: *Error
  on HOST_PEER_ID:
    sig_result <- getKeySignature(label, t)
    if sig_result.success == false:
      error <<- sig_result.error!
    else:
      signature = sig_result.signature!
      id <- getResourceId(label, INIT_PEER_ID)
      nodes <- getNeighbours(id)

      successful: *bool
      for n <- nodes par:
        on n:
          try:
            res <- registerKey(label, t, signature)

            if res.success:
              successful <<- true
            else:
              error <<- res.error

      success <- wait(successful, REPLICATION_FACTOR, DEFAULT_TIMEOUT)

      if success == false:
        error <<- "resource wasn't created: timeout exceeded"
      else:
        resource_id <<- id

  <- resource_id, error

-- Create a resource and register as provider
-- INIT_PEER_ID (current client) will become a provider
func createResourceAndRegisterProvider(label: string, value: string, service_id: ?string) -> ?ResourceId, *Error:
  resource_id: ?ResourceId
  error: *Error

  relay_id: ?string
  relay_id <<- HOST_PEER_ID

  t <- Peer.timestamp_sec()
  on HOST_PEER_ID:
    key_sig_result <- getKeySignature(label, t)

    if key_sig_result.success == false:
      error <<- key_sig_result.error!
    else:
      id <- getResourceId(label, INIT_PEER_ID)
      record_sig_result <- getRecordSignature(id, value, relay_id, service_id, t)
      if record_sig_result.success == false:
        error <<- record_sig_result.error!
      else:
        key_signature = key_sig_result.signature!
        record_signature = record_sig_result.signature!
        nodes <- getNeighbours(id)
        successful: *bool
        for n <- nodes par:
          on n:
            try:
              reg_res <- registerKey(label, t, key_signature)
              if reg_res.success:
                put_res <- putRecord(id, value, relay_id, service_id, t, record_signature)
                if put_res.success:
                  successful <<- true
                else:
                  error <<- put_res.error
              else:
                error <<- reg_res.error

      success <- wait(successful, REPLICATION_FACTOR, DEFAULT_TIMEOUT)
      if success == false:
        error <<- "resource hasn't created: timeout exceeded"
      else:
        resource_id <<- id

  <- resource_id, error

-- Create a resource and make the given node a provider for it
func createResourceAndRegisterNodeProvider(provider_node_id: PeerId, label: string, value: string, service_id: ?string) -> ?ResourceId, *Error:
  resource_id: ?ResourceId
  error: *Error

  t <- Peer.timestamp_sec()

  on provider_node_id:
    key_sig_result <- getKeySignature(label, t)

    if key_sig_result.success == false:
      error <<- key_sig_result.error!
    else:
      id <- getResourceId(label, INIT_PEER_ID)
      record_sig_result <- getHostRecordSignature(id, value, nil, service_id, t)
      if record_sig_result.success == false:
        error <<- record_sig_result.error!
      else:
        key_signature = key_sig_result.signature!
        record_signature = record_sig_result.signature!
        reg_res1 <- registerKey(label, t, key_signature)
        if reg_res1.success == false:
          error <<- reg_res1.error
        else:
          r <- putHostRecord(id, value, nil, service_id, t, record_signature)
          nodes <- getNeighbours(id)
          successful: *bool
          for n <- nodes par:
            on n:
              try:
                reg_res <- registerKey(label, t, key_signature)
                if reg_res.success:
                  prop_res <- propagateHostRecord(r)
                  if prop_res.success:
                    successful <<- true
                  else:
                    error <<- prop_res.error
                else:
                  error <<- reg_res.error

          success <- wait(successful, REPLICATION_FACTOR, DEFAULT_TIMEOUT)
          if success == false:
            error <<- "resource hasn't created: timeout exceeded"
          else:
            resource_id <<- id

  <- resource_id, error

-- Register for a resource as provider
-- Note: resource must be already created
func registerProvider(resource_id: ResourceId, value: string, service_id: ?string) -> bool, *Error:
  success: *bool
  error: *Error
  relay_id: ?string
  relay_id <<- HOST_PEER_ID

  t <- Peer.timestamp_sec()

  on HOST_PEER_ID:
    record_sig_result <- getRecordSignature(resource_id, value, relay_id, service_id, t)

    if record_sig_result.success == false:
      error <<- record_sig_result.error!
      success <<- false
    else:
      record_signature = record_sig_result.signature!
      key, error_get <- getResource(resource_id)
      if key == nil:
        appendErrors(error, error_get)
        success <<- false
      else:
        nodes <- getNeighbours(resource_id)
        successful: *bool
        for n <- nodes par:
          error <<- n
          on n:
            try:
              republish_res <- republishKey(key!)
              if republish_res.success == false:
                error <<- republish_res.error
              else:
                put_res <- putRecord(resource_id, value, relay_id, service_id, t, record_signature)
                if put_res.success:
                  successful <<- true
                else:
                  error <<- put_res.error

        success <- wait(successful, REPLICATION_FACTOR, DEFAULT_TIMEOUT)
        if success! == false:
          error <<- "provider hasn't registered: timeout exceeded"

  <- success!, error

-- Register a node as provider to the given resource
-- Note: resource must be already created
func registerNodeProvider(provider_node_id: PeerId, resource_id: ResourceId, value: string, service_id: ?string) -> bool, *Error:
  success: *bool
  error: *Error
  t <- Peer.timestamp_sec()

  on provider_node_id:
    record_sig_result <- getHostRecordSignature(resource_id, value, nil, service_id, t)
    if record_sig_result.success == false:
      error <<- record_sig_result.error!
      success <<- false
    else:
      record_signature = record_sig_result.signature!
      key, error_get <- getResource(resource_id)
      if key == nil:
        appendErrors(error, error_get)
        success <<- false
      else:
        republish_result <- republishKey(key!)
        if republish_result.success == false:
          error <<- republish_result.error
        else:
          r <- putHostRecord(resource_id, value, nil, service_id, t, record_signature)
          if r.success == false:
            error <<- r.error
            success <<- false
          else:
            on HOST_PEER_ID:
              nodes <- getNeighbours(resource_id)
              successful: *bool
              for n <- nodes par:
                on n:
                  try:
                    republish_res <- republishKey(key!)
                    if republish_res.success == false:
                      error <<- republish_res.error
                    else:
                      prop_res <- propagateHostRecord(r)
                      if prop_res.success:
                        successful <<- true
                      else:
                        error <<- prop_res.error

              success <- wait(successful, REPLICATION_FACTOR, DEFAULT_TIMEOUT)
              if success! == false:
                error <<- "provider hasn't registered: timeout exceeded"

  <- success!, error

-- Find the list of providers' records for the given resource_id
func resolveProviders(resource_id: ResourceId, ack: i16) -> []Record, *Error:
  on HOST_PEER_ID:
    nodes <- getNeighbours(resource_id)
    res: *[]Record
    error: *Error
    successful: *bool
    for n <- nodes par:
      on n:
        try:
          t <- Peer.timestamp_sec()
          get_result <- Registry.get_records(resource_id, t)
          if get_result.success:
            res <<- get_result.result
            successful <<- true
          else:
            error <<- get_result.error

    success <- wait(successful, ack, DEFAULT_TIMEOUT)
    if success == false:
      error <<- "timeout exceeded"

    result <- Registry.merge(res)
    if result.success == false:
      error <<- result.error
  <- result.result, error

-- Execute the given call on providers
-- Note that you can provide another Aqua function as an argument to this one
func executeOnProviders(resource_id: ResourceId, ack: i16, call: Record -> ()) -> *Error:
  providers, error <- resolveProviders(resource_id, ack)
  for r <- providers par:
    on r.peer_id via r.relay_id:
      call(r)
  <- error