{-# LANGUAGE DataKinds      #-}
{-# LANGUAGE NamedFieldPuns #-}
module Observation.JwtCache where

import Network.Wai (Application)

import Network.HTTP.Types
import Test.Hspec         (SpecWith, describe, it)
import Test.Hspec.Wai

import ObsHelper
import PostgREST.Metrics   (MetricsState (..))
import Protolude
import Test.Hspec.Wai.JSON (json)

spec :: SpecWith (SpecState, Application)
spec = describe "Server started with JWT and metrics enabled" $ do
  it "Should not have JWT in cache" $ do
    expectCounters <- checkState' . specMetrics <$> getState

    let auth = genToken [json|{"exp": 9999999999, "role": "postgrest_test_author", "id": "jdoe1"}|]

    expectCounters
      [
        requests (+ 1)
      , hits     (+ 0)
      ] $

         request methodGet "/authors_only" [auth] "" `shouldRespondWith` 200

  it "Should have JWT in cache" $ do
    expectCounters <- checkState' . specMetrics <$> getState

    let auth = genToken [json|{"exp": 9999999999, "role": "postgrest_test_author", "id": "jdoe2"}|]

    expectCounters
      [
        requests (+ 2)
      , hits     (+ 1)
      ] $

         request methodGet "/authors_only" [auth] "" `shouldRespondWith` 200
      *> request methodGet "/authors_only" [auth] "" `shouldRespondWith` 200

  it "Should not cache invalid JWTs" $ do
    expectCounters <- checkState' . specMetrics <$> getState

    let auth = authHeaderJWT "some random bytes"

    expectCounters
      [
        requests (+ 2)
      , hits     (+ 0)
      ] $

         request methodGet "/authors_only" [auth] "" `shouldRespondWith` 401
      *> request methodGet "/authors_only" [auth] "" `shouldRespondWith` 401

  it "Should cache expired JWTs" $ do
    expectCounters <- checkState' . specMetrics <$> getState

    let auth = genToken [json|{"exp": 1, "role": "postgrest_test_author", "id": "jdoe2"}|]

    expectCounters
      [
        requests (+ 2)
      , hits     (+ 1)
      ] $

         request methodGet "/authors_only" [auth] "" `shouldRespondWith` 401
      *> request methodGet "/authors_only" [auth] "" `shouldRespondWith` 401

  it "Should evict entries from the JWT cache (jwt cache max is 2)" $ do
    expectCounters <- checkState' . specMetrics <$> getState

    let jwt1 = genToken [json|{"exp": 9999999999, "role": "postgrest_test_author", "id": "jdoe3"}|]
        jwt2 = genToken [json|{"exp": 9999999999, "role": "postgrest_test_author", "id": "jdoe4"}|]
        jwt3 = genToken [json|{"exp": 9999999999, "role": "postgrest_test_author", "id": "jdoe5"}|]

    expectCounters
      [
        requests  (+ 6)
      , hits      (+ 0)
      , evictions (+ 4)
      ] $

         request methodGet "/authors_only" [jwt1] ""
      *> request methodGet "/authors_only" [jwt2] ""
      *> request methodGet "/authors_only" [jwt3] ""
      *> request methodGet "/authors_only" [jwt1] ""
      *> request methodGet "/authors_only" [jwt2] ""
      *> request methodGet "/authors_only" [jwt3] ""

  it "Should not evict entries from the JWT cache in FIFO order" $ do
    expectCounters <- checkState' . specMetrics <$> getState

    let jwt1 = genToken [json|{"exp": 9999999999, "role": "postgrest_test_author", "id": "jdoe6"}|]
        jwt2 = genToken [json|{"exp": 9999999999, "role": "postgrest_test_author", "id": "jdoe7"}|]
        jwt3 = genToken [json|{"exp": 9999999999, "role": "postgrest_test_author", "id": "jdoe8"}|]

    expectCounters
      [
        requests  (+ 6)
      , hits      (+ 3)
      , evictions (+ 1)
      ] $

         request methodGet "/authors_only" [jwt1] ""
      *> request methodGet "/authors_only" [jwt2] ""
      -- this one should hit the cache
      *> request methodGet "/authors_only" [jwt1] ""
      -- this one should trigger eviction of jwt2 (not FIFO)
      *> request methodGet "/authors_only" [jwt3] ""
      -- these two should hit the cache
      *> request methodGet "/authors_only" [jwt1] ""
      *> request methodGet "/authors_only" [jwt3] ""

  -- This one makes sure we test the scenario when finger
  -- has to move through the whole list first and pass the head
  -- The test case was added based on coverage report
  -- showing this scenario was not covered by previous tests
  it "Should evict entries even though all were hit" $ do
    expectCounters <- checkState' . specMetrics <$> getState

    let jwt1 = genToken [json|{"exp": 9999999999, "role": "postgrest_test_author", "id": "jdoe9"}|]
        jwt2 = genToken [json|{"exp": 9999999999, "role": "postgrest_test_author", "id": "jdoe10"}|]
        jwt3 = genToken [json|{"exp": 9999999999, "role": "postgrest_test_author", "id": "jdoe11"}|]

    expectCounters
      [
        requests  (+ 7)
      , hits      (+ 4)
      , evictions (+ 1)
      ] $

         request methodGet "/authors_only" [jwt1] ""
      *> request methodGet "/authors_only" [jwt2] ""
      -- these two should hit the cache
      *> request methodGet "/authors_only" [jwt1] ""
      *> request methodGet "/authors_only" [jwt2] ""
      -- this one should trigger eviction of jwt1
      *> request methodGet "/authors_only" [jwt3] ""
      -- these two should hit the cache
      *> request methodGet "/authors_only" [jwt2] ""
      *> request methodGet "/authors_only" [jwt3] ""

  where
      genToken = authHeaderJWT . generateJWT
      requests = expectCounter @"jwtCacheRequests"
      hits = expectCounter @"jwtCacheHits"
      evictions = expectCounter @"jwtCacheEvictions"