-- Clean/Types/U32.lean

import Clean.Gadgets.ByteLookup

import Clean.Circuit.Extensions

import Clean.Utils.Bitwise

import Clean.Circuit.Provable

import Clean.Utils.Primes

import Clean.Circuit.Subcircuit

import Clean.Gadgets.Equality

section

variable {p : ℕ} [Fact p.Prime] [p_large_enough: Fact (p > 512)]

structure U32 (T : Type) where
  x0 : T
  x1 : T
  x2 : T
  x3 : T
deriving DecidableEq

namespace U32

def map {α β : Type} (x : U32 α) (f : α → β) : U32 β :=
  ⟨ f x.x0, f x.x1, f x.x2, f x.x3 ⟩

def Normalized (x : U32 (F p)) :=
  x.x0.val < 256 ∧ x.x1.val < 256 ∧ x.x2.val < 256 ∧ x.x3.val < 256

def value (x : U32 (F p)) :=
  x.x0.val + x.x1.val * 256 + x.x2.val * 256^2 + x.x3.val * 256^3

-- Repository definitions used:
content: syntax "infer_constant_length" : tactic

content: macro_rules
  | `(tactic|infer_constant_length) => `(tactic|(
    apply ConstantLength.fromConstantLength
    try simp only [circuit_norm]
    try intros
    try ac_rfl))

example :
  let add (x : Expression F) := do
    let y : Expression F ← witness fun _ => 1
    let z ← witness fun eval => eval (x + y)
    assertZero (x + y - z)
    pure z
  ConstantLength add := by admit /- proof elided -/

content: def F p := ZMod p

content: def KeccakRow.value (row : KeccakRow (F p)) := row.map U64.value

content: def map {α β : Type} (x : U64 α) (f : α → β) : U64 β :=
  ⟨ f x.x0, f x.x1, f x.x2, f x.x3, f x.x4, f x.x5, f x.x6, f x.x7 ⟩

content: structure U64 (T : Type) where
  x0 : T
  x1 : T
  x2 : T
  x3 : T
  x4 : T
  x5 : T
  x6 : T
  x7 : T
deriving DecidableEq

content: def value (x : U64 (F p)) :=
  x.x0.val + x.x1.val * 256 + x.x2.val * 256^2 + x.x3.val * 256^3 +
  x.x4.val * 256^4 + x.x5.val * 256^5 + x.x6.val * 256^6 + x.x7.val * 256^7

content: def map {m : ℕ} (xs : Vector α m) (body : α → Circuit F β)
    (_constant : ConstantLength body := by admit /- proof elided -/
    ) : Circuit F (Vector β m) :=
  xs.mapM body

content: def Circuit (F : Type) [Field F] (α : Type) := ℕ → α × List (Operation F)

content: inductive Operation (F : Type) [Field F] where
  | witness : (m : ℕ) → (compute : Environment F → Vector F m) → Operation F
  | assert : Expression F → Operation F
  | lookup : Lookup F → Operation F
  | subcircuit : {n : ℕ} → Subcircuit F n → Operation F

content: structure Condition (F : Type) [Field F] where
  witness (offset : ℕ) : (m : ℕ) → (Environment F → Vector F m) → Prop := fun _ _ => True
  assert (offset : ℕ) (_ : Expression F) : Prop := True
  lookup (offset : ℕ) (_ : Lookup F) : Prop := True
  subcircuit (offset : ℕ) {m : ℕ} (_ : Subcircuit F m) : Prop := True

content: inductive FlatOperation (F : Type) where
  | witness : (m : ℕ) → (Environment F → Vector F m) → FlatOperation F
  | assert : Expression F → FlatOperation F
  | lookup : Lookup F → FlatOperation F

content: structure Subcircuit (F : Type) [Field F] (offset : ℕ) where
  ops : List (FlatOperation F)

  
  
  
  Soundness : Environment F → Prop
  Completeness : Environment F → Prop
  UsesLocalWitnesses : Environment F → Prop

  
  
  localLength : ℕ

  
  imply_soundness : ∀ env,
    ConstraintsHoldFlat env ops → Soundness env

  
  implied_by_completeness : ∀ env, env.ExtendsVector (localWitnesses env ops) offset →
    Completeness env → ConstraintsHoldFlat env ops

  
  imply_usesLocalWitnesses : ∀ env, env.ExtendsVector (localWitnesses env ops) offset →
    UsesLocalWitnesses env

  
  localLength_eq : localLength = FlatOperation.localLength ops

content: @[circuit_norm]
def localWitnesses (env : Environment F) : (l : List (FlatOperation F)) → Vector F (localLength l)
  | [] => #v[]
  | witness _ compute :: ops => compute env ++ localWitnesses env ops
  | assert _ :: ops | lookup _ :: ops => localWitnesses env ops

content: @[circuit_norm]
def lookup {Row : TypeMap} [ProvableType Row] (table : Table F Row)  (entry : Row (Expression F)) : Circuit F Unit := fun _ =>
  ((), [.lookup { table := table.toRaw, entry := toElements entry }])

content: @[circuit_norm]
def Table.toRaw (table : Table F Row) : RawTable F where
  name := table.name
  arity := size Row
  Contains row := table.Contains (fromElements row)
  Soundness row := table.Soundness (fromElements row)
  Completeness row := table.Completeness (fromElements row)
  imply_soundness row := table.imply_soundness (fromElements row)
  implied_by_completeness row := table.implied_by_completeness (fromElements row)

content: structure RawTable (F : Type) where
  name : String
  arity : ℕ
  Contains : Vector F arity → Prop
  Soundness : Vector F arity → Prop
  Completeness : Vector F arity → Prop
  imply_soundness : ∀ row, Contains row → Soundness row
  implied_by_completeness : ∀ row, Completeness row → Contains row

content: structure StaticTable (F : Type) (Row : TypeMap) [ProvableType Row] where
  name : String
  length : ℕ
  row : Fin length → Row F
  
  
  
  index : Row F → ℕ
  Spec : Row F → Prop
  contains_iff : ∀ t, (∃ i, t = row i) ↔ Spec t

content: def Contains (table : StaticTable F Row) (row : Row F) :=
  ∃ i : Fin table.length, row = table.row i

content: instance ProvableType.fromStruct {α : TypeMap} [ProvableStruct α] : ProvableType α where
  size := combinedSize α
  toElements x :=
    toComponents x |> componentsToElements (components α) |>.cast combinedSize_eq.symm
  fromElements v :=
    v.cast combinedSize_eq |> componentsFromElements (components α) |> fromComponents
  fromElements_toElements x := by admit /- proof elided -/

content: @[reducible]
def TypeMap := Type → Type

content: structure Table (F : Type) (Row : TypeMap) [ProvableType Row] where
  name : String
   
  Contains : Row F → Prop

   
  Soundness : Row F → Prop
  Completeness : Row F → Prop

  imply_soundness : ∀ row, Contains row → Soundness row
  implied_by_completeness : ∀ row, Completeness row → Contains row

content: inductive Expression (F : Type) where
  | var : Variable F -> Expression F
  | const : F -> Expression F
  | add : Expression F -> Expression F -> Expression F
  | mul : Expression F -> Expression F -> Expression F

content: structure Variable (F : Type) where
  index : ℕ

content: def const (x : α F) : Var α F :=
  let values : Vector F _ := toElements x
  fromVars (values.map .const)

content: @[reducible] def Var (M : TypeMap) (F : Type) := M (Expression F)

content: @[circuit_norm]
def fromVars (vars : Vector (Expression F) (size M)) := fromElements vars

content: structure Lookup (F : Type) where
  table : RawTable F
  entry : Vector (Expression F) table.arity

content: class Witnessable (F : Type) [Field F] (value : outParam TypeMap) (var : TypeMap) [ProvableType value] where
  witness : ((Environment F) → value F) → Circuit F (var F)
  var_eq : var F = value (Expression F) := by admit /- proof elided -/

content: structure Environment (F : Type) where
  get : ℕ → F

content: @[circuit_norm]
def localLength : List (FlatOperation F) → ℕ
  | [] => 0
  | witness m _ :: ops => m + localLength ops
  | assert _ :: ops | lookup _ :: ops => localLength ops

content: def ConstraintsHoldFlat (eval : Environment F) : List (FlatOperation F) → Prop
  | [] => True
  | op :: ops => match op with
    | assert e => (eval e = 0) ∧ ConstraintsHoldFlat eval ops
    | lookup { table, entry } =>
      table.Contains (entry.map eval) ∧ ConstraintsHoldFlat eval ops
    | _ => ConstraintsHoldFlat eval ops

content: class ConstantLength (circuit : α → Circuit F β) where
  localLength : ℕ
  localLength_eq : ∀ (a : α) (n : ℕ), (circuit a).localLength n = localLength

content: def ConstantLength.fromConstantLength {circuit : α → Circuit F β} [Inhabited α]
    (h : ∀ (a : α) n, (circuit a).localLength n = (circuit default).localLength 0) : ConstantLength circuit where
  localLength := (circuit default).localLength 0
  localLength_eq a n := h a n

content: def KeccakRow.Normalized (row : KeccakRow (F p)) :=
  ∀ i : Fin 5, row[i.val].Normalized

content: def BLAKE3State.Normalized (state : BLAKE3State (F p)) :=
  ∀ i : Fin 16, state[i.val].Normalized

content: def KeccakBlock.value (block : KeccakBlock (F p)) := block.map U64.value

content: def BLAKE3State.value (state : BLAKE3State (F p)) := state.map U32.value

content: def KeccakState.value (state : KeccakState (F p)) := state.map U64.value

content: def KeccakBlock.Normalized (block : KeccakBlock (F p)) :=
  ∀ i : Fin RATE, block[i.val].Normalized

content: @[reducible] def RATE := 17
example : RATE + CAPACITY = 25 := rfl

content: @[reducible] def CAPACITY := 8

content: def KeccakState.Normalized (state : KeccakState (F p)) :=
  ∀ i : Fin 25, state[i.val].Normalized

-- Repository lemmas used:
content: theorem List.getElem_append_left{α : Type u_1} {l₁ l₂ : List α} {i : Nat} (hn : i < l₁.length) :\n(l₁ ++ l₂)[i] = l₁[i]

-- Local definitions used:
content: structure U32 (T : Type) where
  x0 : T
  x1 : T
  x2 : T
  x3 : T
deriving DecidableEq

content: def map {α β : Type} (x : U32 α) (f : α → β) : U32 β :=
  ⟨ f x.x0, f x.x1, f x.x2, f x.x3 ⟩

content: def Normalized (x : U32 (F p)) :=
  x.x0.val < 256 ∧ x.x1.val < 256 ∧ x.x2.val < 256 ∧ x.x3.val < 256

content: def value (x : U32 (F p)) :=
  x.x0.val + x.x1.val * 256 + x.x2.val * 256^2 + x.x3.val * 256^3

-- Local lemmas used:
content: omit [Fact (Nat.Prime p)] p_large_enough in
theorem value_horner (x : U32 (F p)) : x.value =
    x.x0.val + 2^8 * (x.x1.val + 2^8 * (x.x2.val + 2^8 * x.x3.val))

-- Target theorem and proof:
omit p_large_enough in
lemma value_injective_on_normalized (x y : U32 (F p))
    (hx : x.Normalized) (hy : y.Normalized) :
    x.value = y.value → x = y
:= by
  intro h_eq
  -- Use horner form of value
  have hx_value := U32.value_horner x
  have hy_value := U32.value_horner y

  simp only [U32.Normalized] at hx hy

  have : x.x0 = y.x0 := by apply ZMod.val_injective; omega
  have : x.x1 = y.x1 := by apply ZMod.val_injective; omega
  have : x.x2 = y.x2 := by apply ZMod.val_injective; omega
  have : x.x3 = y.x3 := by apply ZMod.val_injective; omega

  cases x; cases y
  simp_all