; Phase 1 — object: blob/tree/commit/tag as content-addressed typed objects.
; Fixture repo: blobs a/b/c, nested tree (a.txt b.txt sub/c.txt), two commits
; (c2 modifies a.txt, parent c1), tag v1 -> c1. Reused as the assertion target.

(define git-fix-db (persist/mem-backend))
(define git-fix (git/repo git-fix-db))

(define git-fix-blob-a (git/write-blob git-fix "hello\n"))
(define git-fix-blob-b (git/write-blob git-fix "world\n"))
(define git-fix-blob-c (git/write-blob git-fix "sub\n"))
(define git-fix-blob-a2 (git/write-blob git-fix "hello2\n"))

(define
  git-fixt-entries3
  (fn
    (acid bcid subcid)
    (assoc
      (assoc
        (assoc {} "a.txt" (git/tree-entry "blob" acid))
        "b.txt"
        (git/tree-entry "blob" bcid))
      "sub"
      (git/tree-entry "tree" subcid))))

(define
  git-fix-subtree-cid
  (git/write
    git-fix
    (git/tree
      (assoc {} "c.txt" (git/tree-entry "blob" git-fix-blob-c)))))

(define
  git-fix-tree1-cid
  (git/write
    git-fix
    (git/tree
      (git-fixt-entries3 git-fix-blob-a git-fix-blob-b git-fix-subtree-cid))))

(define
  git-fix-tree2-cid
  (git/write
    git-fix
    (git/tree
      (git-fixt-entries3 git-fix-blob-a2 git-fix-blob-b git-fix-subtree-cid))))

(define
  git-fix-commit1-cid
  (git/write git-fix (git/commit git-fix-tree1-cid (list) {:message "c1" :time 1 :author "ada"})))

(define
  git-fix-commit2-cid
  (git/write
    git-fix
    (git/commit git-fix-tree2-cid (list git-fix-commit1-cid) {:message "c2" :time 2 :author "ada"})))

(define
  git-fix-tag-cid
  (git/write git-fix (git/tag git-fix-commit1-cid "v1" {:message "first" :tagger "ada"})))

; ---- constructors + types ----
(git-test "blob is typed" (git/object-type (git/blob "x")) "blob")
(git-test "blob? true on blob" (git/blob? (git/blob "x")) true)
(git-test
  "blob? false on commit"
  (git/blob? (git/commit "t" (list) {}))
  false)
(git-test "tree? true on tree" (git/tree? (git/tree {})) true)
(git-test
  "commit? true on commit"
  (git/commit? (git/commit "t" (list) {}))
  true)
(git-test "tag? true on tag" (git/tag? (git/tag "c" "v" {})) true)
(git-test "blob-data reads back" (git/blob-data (git/blob "hi")) "hi")

; ---- cid: deterministic structural identity ----
(git-test
  "cid deterministic"
  (equal? (git/cid (git/blob "same")) (git/cid (git/blob "same")))
  true)
(git-test
  "cid differs by content"
  (equal? (git/cid (git/blob "a")) (git/cid (git/blob "b")))
  false)
(git-test
  "cid ignores dict insertion order"
  (equal?
    (git/cid (assoc (assoc {} :type "blob") :data "x"))
    (git/cid (assoc (assoc {} :data "x") :type "blob")))
  true)
(git-test
  "cid carries the native scheme prefix"
  (starts-with? (git/cid (git/blob "x")) "sx1:")
  true)

; ---- write / read / has ----
(git-test
  "write returns the object cid"
  (equal? git-fix-blob-a (git/cid (git/blob "hello\n")))
  true)
(git-test
  "read round-trips blob data"
  (git/blob-data (git/read git-fix git-fix-blob-a))
  "hello\n")
(git-test
  "read round-trips structurally"
  (equal? (git/read git-fix git-fix-blob-a) (git/blob "hello\n"))
  true)
(git-test "has? true after write" (git/has? git-fix git-fix-blob-a) true)
(git-test "has? false for unknown cid" (git/has? git-fix "sx1:nope") false)
(git-test "read unknown cid gives nil" (git/read git-fix "sx1:nope") nil)
(git-test
  "rewrite is idempotent, same cid"
  (equal? (git/write git-fix (git/blob "hello\n")) git-fix-blob-a)
  true)

; ---- structural identity across separately built objects ----
(git-test
  "separately built identical tree shares the cid"
  (equal?
    (git/write
      git-fix
      (git/tree
        (git-fixt-entries3 git-fix-blob-a git-fix-blob-b git-fix-subtree-cid)))
    git-fix-tree1-cid)
  true)
(git-test
  "changed entry changes the tree cid"
  (equal? git-fix-tree1-cid git-fix-tree2-cid)
  false)

; ---- tree accessors ----
(git-test
  "tree entry lookup by name"
  (git/entry-cid
    (git/tree-entry-for (git/read git-fix git-fix-tree1-cid) "a.txt"))
  git-fix-blob-a)
(git-test
  "tree entry kind"
  (git/entry-kind
    (git/tree-entry-for (git/read git-fix git-fix-tree1-cid) "sub"))
  "tree")
(git-test
  "tree-names sorted"
  (=
    (git/tree-names (git/read git-fix git-fix-tree1-cid))
    (list "a.txt" "b.txt" "sub"))
  true)

; ---- commit accessors ----
(git-test
  "commit tree cid"
  (git/commit-tree (git/read git-fix git-fix-commit1-cid))
  git-fix-tree1-cid)
(git-test
  "root commit has no parents"
  (git/commit-parents (git/read git-fix git-fix-commit1-cid))
  (list))
(git-test
  "child commit records its parent"
  (git/commit-parents (git/read git-fix git-fix-commit2-cid))
  (list git-fix-commit1-cid))
(git-test
  "commit author round-trips"
  (git/commit-author (git/read git-fix git-fix-commit1-cid))
  "ada")
(git-test
  "commit message round-trips"
  (git/commit-message (git/read git-fix git-fix-commit2-cid))
  "c2")
(git-test
  "commit cids differ across history"
  (equal? git-fix-commit1-cid git-fix-commit2-cid)
  false)

; ---- typed extensibility (the reason for native CID) ----
(git-test
  "extra commit field round-trips"
  (get
    (git/read
      git-fix
      (git/write git-fix (git/commit "t" (list) {:message "m" :co-authored-by "claude"})))
    :co-authored-by)
  "claude")
(git-test
  "extra field changes the cid"
  (equal?
    (git/cid (git/commit "t" (list) {:m 1}))
    (git/cid (git/commit "t" (list) {})))
  false)
(git-test
  "protected keys win over meta"
  (git/commit-tree (git/commit "t" (list) {:tree "evil"}))
  "t")

; ---- tag ----
(git-test
  "tag target"
  (git/tag-target (git/read git-fix git-fix-tag-cid))
  git-fix-commit1-cid)
(git-test "tag name" (git/tag-name (git/read git-fix git-fix-tag-cid)) "v1")
(git-test
  "tag? on read-back"
  (git/tag? (git/read git-fix git-fix-tag-cid))
  true)

; ---- full walk: commit -> tree -> subtree -> blob ----
(git-test
  "walk commit to nested blob"
  (git/blob-data
    (git/read
      git-fix
      (git/entry-cid
        (git/tree-entry-for
          (git/read
            git-fix
            (git/entry-cid
              (git/tree-entry-for
                (git/read
                  git-fix
                  (git/commit-tree (git/read git-fix git-fix-commit1-cid)))
                "sub")))
          "c.txt"))))
  "sub\n")

; ---- repos are namespaced within one backend ----
(git-test
  "objects are invisible across repo namespaces"
  (let
    ((db (persist/mem-backend)))
    (let
      ((ra (git/repo-named db "a")) (rb (git/repo-named db "b")))
      (let ((cid (git/write-blob ra "x"))) (git/has? rb cid))))
  false)
(git-test
  "same content, same cid in any repo"
  (let
    ((db (persist/mem-backend)))
    (equal?
      (git/write-blob (git/repo-named db "a") "x")
      (git/write-blob (git/repo-named db "b") "x")))
  true)