-- SPDX-FileCopyrightText: Copyright (c) 2025 Objectionary.com
-- SPDX-License-Identifier: MIT

module LaTeX (explainRules, programToLaTeX) where

import Ast (Program)
import Data.List (intercalate)
import Data.Maybe (fromMaybe)
import Pretty (Encoding (ASCII), PrintMode, prettyProgram')
import qualified Yaml as Y

escapeUnprintedChars :: String -> String
escapeUnprintedChars [] = []
escapeUnprintedChars (ch : rest) = case ch of
  '$' -> "\\char36{}" ++ escapeUnprintedChars rest
  '@' -> "\\char64{}" ++ escapeUnprintedChars rest
  '^' -> "\\char94{}" ++ escapeUnprintedChars rest
  _ -> ch : escapeUnprintedChars rest

programToLaTeX :: Program -> PrintMode -> String
programToLaTeX prog mode =
  unlines
    [ "\\documentclass{article}",
      "\\usepackage{eolang}",
      "\\begin{document}",
      "\\begin{phiquation}",
      escapeUnprintedChars (prettyProgram' prog mode ASCII),
      "\\end{phiquation}",
      "\\end{document}"
    ]

-- @todo #114:30min Implement LaTeX conversion for rules.
--  Convert Rule data structure to LaTeX inference rule format.
--  Each rule should be formatted as a LaTeX inference rule with
--  pattern, result, and optional conditions.
--  Tests must be added for LaTeX conversion logic.
explainRule :: Y.Rule -> String
explainRule rule = "\\rule{" ++ fromMaybe "unnamed" (Y.name rule) ++ "}"

-- @todo #114:30min Create LaTeX document wrapper.
--  Generate proper LaTeX document with tabular format for rules.
--  Each rule should be   in its own tabular environment.
--  Include tests for document structure generation.
explainRules :: [Y.Rule] -> String
explainRules rules' =
  unlines
    [ "\\documentclass{article}",
      "\\usepackage{amsmath}",
      "\\begin{document}"
    ]
    ++ unlines (map explainRule rules')
    ++ "\\end{document}"