module Stackctl.AWS.Scope
  ( AwsScope(..)
  , awsScopeSpecPatterns
  , awsScopeSpecStackName
  , HasAwsScope(..)
  , fetchAwsScope
  ) where

import Stackctl.Prelude

import qualified Data.Text as T
import Stackctl.AWS
import System.Environment (lookupEnv)
import System.FilePath (joinPath, splitPath)
import System.FilePath.Glob (Pattern, compile, match)

data AwsScope = AwsScope
  { awsAccountId :: AccountId
  , awsAccountName :: Text
  , awsRegion :: Region
  }
  deriving stock (Eq, Show, Generic)
  deriving anyclass ToJSON

awsScopeSpecPatterns :: AwsScope -> [Pattern]
awsScopeSpecPatterns AwsScope {..} =
  [ compile
    $ "stacks"
    </> unpack (unAccountId awsAccountId)
    <> ".*"
    </> unpack (fromRegion awsRegion)
    <> "**"
    </> "*"
    <.> "yaml"
  , compile
    $ "stacks"
    </> "*."
    <> unpack (unAccountId awsAccountId)
    </> unpack (fromRegion awsRegion)
    <> "**"
    </> "*"
    <.> "yaml"
  ]

awsScopeSpecStackName :: AwsScope -> FilePath -> Maybe StackName
awsScopeSpecStackName scope path = do
  guard $ any (`match` path) $ awsScopeSpecPatterns scope

  -- once we've guarded that the path matches our scope patterns, we can play it
  -- pretty fast and loose with the "parsing" step
  pure
    $ path                -- stacks/account/region/x/y.yaml
    & splitPath           -- [stacks/, account/, region/, x/, y.yaml]
    & drop 3              -- [x, y.yaml]
    & joinPath            -- x/y.yaml
    & dropExtension       -- x/y
    & pack
    & T.replace "/" "-"   -- x-y
    & StackName

class HasAwsScope env where
  awsScopeL :: Lens' env AwsScope

instance HasAwsScope AwsScope where
  awsScopeL = id

fetchAwsScope
  :: (MonadResource m, MonadReader env m, HasAwsEnv env) => m AwsScope
fetchAwsScope =
  AwsScope
    <$> awsGetCallerIdentityAccount
    <*> liftIO (maybe "unknown" pack <$> lookupEnv "AWS_PROFILE")
    <*> awsEc2DescribeFirstAvailabilityZoneRegionName