{-# LANGUAGE OverloadedStrings #-}

import Data.Text (Text)
import qualified Data.Text as T
import Text.XML
import Text.XML.Writer
import qualified Data.ByteString.Lazy as BL

data Plant = Plant
  { plantId :: Int
  , plantName :: Text
  , plantOrigin :: [Text]
  } deriving (Show)

-- Plant will be mapped to XML. We use the Text.XML.Writer library
-- to define how our Plant type should be serialized to XML.
instance ToXML Plant where
  toXML plant = elementA "plant" [("id", T.pack $ show $ plantId plant)] $ do
    element "name" $ content $ plantName plant
    mapM_ (element "origin" . content) $ plantOrigin plant

-- Function to convert Plant to a string representation
plantToString :: Plant -> String
plantToString p = "Plant id=" ++ show (plantId p) ++ ", name=" ++ T.unpack (plantName p) ++ ", origin=" ++ show (plantOrigin p)

main :: IO ()
main = do
  let coffee = Plant 27 "Coffee" ["Ethiopia", "Brazil"]

  -- Emit XML representing our plant
  let xmlDoc = document (elementA "plant" [("id", "27")] $ do
        element "name" $ content "Coffee"
        element "origin" $ content "Ethiopia"
        element "origin" $ content "Brazil")
  
  let xmlString = BL.unpack $ renderLBS def xmlDoc
  putStrLn xmlString

  -- To add a generic XML header to the output, we prepend it
  putStrLn $ "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" ++ xmlString

  -- Use parseText to parse a Text with XML into a Document.
  -- If the XML is malformed or cannot be mapped onto our structure,
  -- a descriptive error will be returned.
  case parseText def (T.pack xmlString) of
    Left err -> putStrLn $ "Failed to parse XML: " ++ show err
    Right _ -> putStrLn $ plantToString coffee

  let tomato = Plant 81 "Tomato" ["Mexico", "California"]

  -- In Haskell, we can represent nested XML structures using nested calls to 'element'
  let nestingDoc = document $ element "nesting" $ do
        element "parent" $ do
          element "child" $ do
            toXML coffee
            toXML tomato
  
  let nestingXml = BL.unpack $ renderLBS def nestingDoc
  putStrLn nestingXml