{-# LANGUAGE DataKinds #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeOperators #-}

module GitHubRelease where

import qualified Data.Aeson as Aeson
import qualified Data.ByteString.Char8 as BS8
import qualified Data.ByteString.Lazy as BSL
import qualified Data.HashMap.Strict as HashMap
import qualified Data.Text as Text
import qualified Data.Version as Version
import qualified GHC.Generics as Generics
import qualified Network.HTTP.Client as Client
import qualified Network.HTTP.Client.TLS as TLS
import qualified Network.HTTP.Types as HTTP
import qualified Network.Mime as MIME
import qualified Network.URI.Template as Template
import qualified Network.URI.Template.Types as Template
import qualified Options.Generic as Options
import qualified Paths_github_release as This
import qualified System.IO as IO
import qualified Text.Printf as Printf

data Command
    = Upload
        { file :: FilePath Options.<?>
            "The path to the local file to upload."
        , name :: String Options.<?>
            "The name to give the file on the release."
        , owner :: String Options.<?>
            "The GitHub owner, either a user or organization."
        , repo :: String Options.<?>
            "The GitHub repository name."
        , tag :: String Options.<?>
            "The tag name."
        , token :: String Options.<?>
            "Your OAuth2 token."
        }
    | Version
    deriving (Generics.Generic, Show)

instance Options.ParseRecord Command

main :: IO ()
main = do
    command <- Options.getRecord (Text.pack "Upload a file to a GitHub release.")
    runCommand command

runCommand :: Command -> IO ()
runCommand command = case command of
    Upload aFile aName anOwner aRepo aTag aToken -> upload
        (Options.unHelpful aToken)
        (Options.unHelpful anOwner)
        (Options.unHelpful aRepo)
        (Options.unHelpful aTag)
        (Options.unHelpful aFile)
        (Options.unHelpful aName)
    Version -> putStrLn versionString

upload :: String -> String -> String -> String -> FilePath -> String -> IO ()
upload aToken anOwner aRepo aTag aFile aName = do
    manager <- Client.newManager TLS.tlsManagerSettings
    uploadUrl <- getUploadUrl manager aToken anOwner aRepo aTag
    response <- uploadFile manager uploadUrl aToken aFile aName
    case HTTP.statusCode (Client.responseStatus response) of
        201 -> pure ()
        _ -> do
            IO.hPrint IO.stderr response
            BSL.hPutStr IO.stderr (Client.responseBody response)
            fail "Failed to upload file to release!"

getUploadUrl :: Client.Manager -> String -> String -> String -> String -> IO Template.UriTemplate
getUploadUrl manager aToken anOwner aRepo aTag = do
    (Right json) <- getTag manager aToken anOwner aRepo aTag
    let (Just (Aeson.String text)) = HashMap.lookup (Text.pack "upload_url") json
    let uploadUrl = Text.unpack text
    let (Right template) = Template.parseTemplate uploadUrl
    pure template

getTag :: Client.Manager -> String -> String -> String -> String -> IO (Either String Aeson.Object)
getTag manager aToken anOwner aRepo aTag = do
    let format = "https://api.github.com/repos/%s/%s/releases/tags/%s"
    let url = Printf.printf format anOwner aRepo aTag
    initialRequest <- Client.parseUrl url
    let request = initialRequest
            { Client.requestHeaders =
                [ authorizationHeader aToken
                , userAgentHeader
                ]
            }
    response <- Client.httpLbs request manager
    let body = Client.responseBody response
    let json = Aeson.eitherDecode body
    return json

authorizationHeader :: String -> HTTP.Header
authorizationHeader aToken =
    ( HTTP.hAuthorization
    , BS8.pack (Printf.printf "token %s" aToken)
    )

userAgentHeader :: HTTP.Header
userAgentHeader =
    ( HTTP.hUserAgent
    , BS8.pack userAgent
    )

userAgent :: String
userAgent = Printf.printf "%s/%s-%s" "tfausak" "github-release" versionString

versionString :: String
versionString = Version.showVersion This.version

uploadFile :: Client.Manager -> Template.UriTemplate -> String -> FilePath -> String -> IO (Client.Response BSL.ByteString)
uploadFile manager template aToken aFile aName = do
    contents <- BSL.readFile aFile
    let body = Client.RequestBodyLBS contents
    uploadBody manager template aToken body aName

uploadBody :: Client.Manager -> Template.UriTemplate -> String -> Client.RequestBody -> String -> IO (Client.Response BSL.ByteString)
uploadBody manager template aToken body aName = do
    let url = Template.render template
            [ ("name", Template.WrappedValue (Template.Single aName))
            ]
    initialRequest <- Client.parseUrl url
    let request = initialRequest
            { Client.method = BS8.pack "POST"
            , Client.requestBody = body
            , Client.requestHeaders =
                [ authorizationHeader aToken
                , (HTTP.hContentType, MIME.defaultMimeLookup (Text.pack aName))
                , userAgentHeader
                ]
            }
    Client.httpLbs request manager