Replace makePDF with direct XeLaTeX processing to eliminate API mismatch

- Remove Text.Pandoc.PDF dependency and dummy Pandoc document
- Add direct xelatex invocation with temporary file handling
- Improve error reporting with LaTeX log file parsing
- Add temporary package dependency for proper temp file cleanup
- Maintain same external API while cleaning internal architecture
- Eliminate architectural mismatch between our pipeline and Pandoc's expectations

The previous code used makePDF in a way that fought against its intended usage,
requiring a dummy Pandoc document. Now we directly call xelatex after our
custom LaTeX template processing, creating a cleaner separation of concerns.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

docster.cabal

@@ -42,7 +42,8 @@ library
       hashable >=1.4 && <1.6,
       pandoc >=3.0 && <3.2,
       pandoc-types >=1.23 && <1.25,
-      bytestring >=0.11 && <0.13
+      bytestring >=0.11 && <0.13,
+      temporary >=1.3 && <1.4
   default-language:    Haskell2010
 
 executable docster

src/Docster/Compiler.hs

@@ -12,13 +12,14 @@ import Docster.Types
 import Docster.Transform (transformDocument)
 import Docster.LaTeX (latexTemplate)
 import Text.Pandoc
-import Text.Pandoc.PDF (makePDF)
 import Data.Text (Text)
 import qualified Data.Text as T
 import qualified Data.Text.IO as TIO
-import qualified Data.ByteString.Lazy as BL
-import System.FilePath (takeDirectory, replaceExtension)
-import System.Process (callProcess)
+import System.FilePath (takeDirectory, replaceExtension, (</>))
+import System.Process (callProcess, readProcessWithExitCode)
+import System.IO.Temp (withSystemTempDirectory)
+import System.Directory (copyFile, doesFileExist)
+import System.Exit (ExitCode(..))
 import Control.Exception (throwIO)
 import Control.Monad (void)
 
@@ -56,20 +57,53 @@ htmlStrategy = CompilationStrategy
   , csSuccessMessage = \path -> successEmoji <> " HTML written to " <> T.pack path
   }
 
--- | Process PDF output: LaTeX template application and PDF generation
+-- | Process PDF output: LaTeX template application and direct XeLaTeX compilation
 processPDFOutput :: Text -> String -> IO (Either DocsterError ())
 processPDFOutput latexOutput outputPath = do
   let completeLatex = latexTemplate latexOutput
-  -- We need a Pandoc document for makePDF, but it's not used in the template function
-  -- Create a minimal document for the API
-  let dummyDoc = Pandoc nullMeta []
-  pdfResult <- runIO $ makePDF "xelatex" [] (\_ _ -> return completeLatex) def dummyDoc
-  case pdfResult of
-    Left err -> return $ Left $ PDFGenerationError $ T.pack $ show err
-    Right (Left err) -> return $ Left $ PDFGenerationError $ T.pack $ show err
-    Right (Right bs) -> do
-      BL.writeFile outputPath bs
-      return $ Right ()
+  
+  -- Use temporary directory for LaTeX compilation
+  withSystemTempDirectory "docster-latex" $ \tempDir -> do
+    let texFile = tempDir </> "document.tex"
+        pdfFile = tempDir </> "document.pdf"
+        logFile = tempDir </> "document.log"
+    
+    -- Write LaTeX content to temporary file
+    TIO.writeFile texFile completeLatex
+    
+    -- Run XeLaTeX compilation
+    (exitCode, _stdout, stderr) <- readProcessWithExitCode "xelatex" 
+      [ "-output-directory=" <> tempDir
+      , "-interaction=nonstopmode"  -- Don't stop on errors
+      , texFile
+      ] ""
+    
+    case exitCode of
+      ExitSuccess -> do
+        -- Check if PDF was actually generated
+        pdfExists <- doesFileExist pdfFile
+        if pdfExists
+          then do
+            -- Copy the generated PDF to the final location
+            copyFile pdfFile outputPath
+            return $ Right ()
+          else do
+            -- PDF generation failed, read log for details
+            logExists <- doesFileExist logFile
+            logContent <- if logExists 
+              then TIO.readFile logFile 
+              else return "No log file generated"
+            return $ Left $ PDFGenerationError $ 
+              "PDF file not generated. LaTeX log:\n" <> logContent
+      ExitFailure code -> do
+        -- LaTeX compilation failed, read log for details
+        logExists <- doesFileExist logFile
+        logContent <- if logExists 
+          then TIO.readFile logFile 
+          else return (T.pack stderr)
+        return $ Left $ PDFGenerationError $ 
+          "XeLaTeX compilation failed (exit code " <> T.pack (show code) <> "):\n" <> 
+          T.pack stderr <> "\n\nLaTeX log:\n" <> logContent
 
 -- | Process HTML output: file writing and browser opening
 processHTMLOutput :: Text -> String -> IO (Either DocsterError ())