-- SPDX-FileCopyrightText: 2026 Alexandra de Wit
--
-- SPDX-License-Identifier: MIT

{- | A projection scoped to the upstream bytes it came from.
Adapters retain the fetch digest while transforming either the typed or raw view.
-}
module Ecluse.Core.Snapshot (
    Snapshot (..),
    ContentDigest,
    digestBytes,
    digestFromContext,
) where

import Crypto.Hash (Context, SHA256, hashFinalize)
import Data.ByteArray qualified as BA

{- | A view paired with the digest computed before projection. Producers must use the same fetch.
Mapping preserves the snapshot scope.
-}
data Snapshot a = Snapshot
    { forall a. Snapshot a -> ContentDigest
snapshotDigest :: ContentDigest
    , forall a. Snapshot a -> a
snapshotValue :: a
    }
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-- | Fingerprint the exact upstream bytes used to build a manifest.
newtype ContentDigest = ContentDigest ByteString
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-- | The digest's raw 32 bytes, for feeding into a wider fingerprint.
digestBytes :: ContentDigest -> ByteString
digestBytes :: ContentDigest -> ByteString
digestBytes (ContentDigest ByteString
bytes) = ByteString
bytes

-- | Finish the SHA-256 state accumulated from the exact consumed source chunks.
digestFromContext :: Context SHA256 -> ContentDigest
digestFromContext :: Context SHA256 -> ContentDigest
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