{-# LANGUAGE OverloadedStrings #-}

-- | KiTov — fitness evaluation.
--
-- Architecture §3.1:
--   kiTov :: ProcessedResult -> Specification -> Evaluation
--   data Evaluation = Tov | LoTov Text | Teiku
--
-- Evaluates whether processed output fits the specification.
-- "And God saw that it was good" — the evaluation against the source.
--
-- Ki tov is not approval. It is verification against specification.
-- The specification is Torah (L1). The evaluation checks:
--   1. Are the roots real? (found in L1)
--   2. Are the references valid? (point to existing verses)
--   3. Are dual readings preserved? (ketiv/qere not collapsed)
module Shoresh.KiTov
  ( kiTov
  , verifyRootsExist
  , verifyReferences
  ) where

import Shoresh.Types
import Shoresh.Lexicon (ShoreshLexicon, lookupRoot)
import Data.Text (Text)
import qualified Data.Text as T
import Data.Maybe (isNothing)

-- | Evaluate a processed result against the specification (lexicon).
kiTov :: ProcessedResult -> ShoreshLexicon -> Evaluation
kiTov result lexicon =
  let rootCheck = verifyRootsExist (prRoots result) lexicon
      refCheck  = verifyReferences (prRoots result)
  in case (rootCheck, refCheck) of
    (Tov, Tov)        -> Tov
    (LoTov r, _)      -> LoTov r
    (_, LoTov r)      -> LoTov r
    (Teiku, _)        -> Teiku
    (_, Teiku)        -> Teiku

-- | Verify that all roots in the result exist in the lexicon.
verifyRootsExist :: [ShoreshEntry] -> ShoreshLexicon -> Evaluation
verifyRootsExist entries lexicon =
  let missing = [ seShoresh e | e <- entries
                , isNothing (lookupRoot (seShoresh e) lexicon) ]
  in case missing of
    []  -> Tov
    ms  -> LoTov $ "Roots not found in lexicon: "
              <> T.intercalate ", " (map shoreshToText ms)

-- | Verify that Torah references in the entries are structurally valid.
-- (Range checks — the full check against L1 files happens at the pipeline level.)
verifyReferences :: [ShoreshEntry] -> Evaluation
verifyReferences entries =
  let invalid = concatMap checkEntry entries
  in case invalid of
    [] -> Tov
    msgs -> LoTov $ T.intercalate "; " msgs
  where
    checkEntry entry = concatMap checkRef (seTorahOccurrences entry)
    checkRef ref
      | refChapter ref < 1 = ["Invalid chapter: " <> T.pack (show (refChapter ref))]
      | refVerse ref < 1   = ["Invalid verse: " <> T.pack (show (refVerse ref))]
      | otherwise          = []