import Mathlib
import OAI.Computability.MaxCut.Machines.MachineBinaryParsing
import OAI.Computability.MaxCut.Machines.MachineBinaryRenameLoop

namespace OAI

/-!
The word-level correspondence used by the ordinary-binary renaming machine.
Literal occurrences stay in clause order, and equality is tested on canonical
binary payloads. The output body consists of the first occurrence index and
the sign of every literal, in the inherited dense formula codec.
-/

namespace MaxCutGames.BinaryRenameWords

open BinaryFormula MaxCutGames.Foundations

def clauseLiterals (c : Clause) : List Literal := [(c)[0], (c)[1], (c)[2]]

def literals (clauses : List Clause) : List Literal := clauses.flatMap clauseLiterals

def token (literal : Literal) : BinaryNameSearch.Token :=
  (literal.positive, literal.name.bits)

def tokens (clauses : List Clause) : List BinaryNameSearch.Token :=
  (literals clauses).map token

@[simp] theorem literals_nil : literals [] = [] := rfl

@[simp] theorem literals_cons (c : Clause) (cs : List Clause) :
    literals (c :: cs) = (c)[0] :: (c)[1] :: (c)[2] :: literals cs := rfl

@[simp] theorem literals_length (cs : List Clause) :
    (literals cs).length = 3 * cs.length := by
  induction cs with
  | nil => rfl
  | cons c cs ih => simp only [literals_cons, List.length_cons, ih]; omega

@[simp] theorem tokens_length (cs : List Clause) :
    (tokens cs).length = 3 * cs.length := by simp [tokens]

theorem literals_names (F : Formula) :
    (literals F.clauses).map Literal.name = sourceNames F := by
  simp only [literals, sourceNames, List.map_flatMap]
  rfl

theorem tokens_payloads (F : Formula) :
    BinaryNameSearch.payloads (tokens F.clauses) = (sourceNames F).map Nat.bits := by
  rw [← literals_names]
  simp only [BinaryNameSearch.payloads, tokens, List.map_map, token, Function.comp_def]

theorem token_bits (literal : Literal) :
    BinaryNameSearch.tokenBits (token literal) = BinaryEncoding.literalBits literal := by
  simp only [BinaryNameSearch.tokenBits, token, BinaryEncoding.literalBits,
    BinaryEncoding.nameBits, BinaryParsing.frame_eq]

/-- The marker-removal machine's actual output is the search machine's stream. -/
theorem tokens_stream (cs : List Clause) :
    BinaryNameSearch.stream (tokens cs) = BinaryTokenMachine.tokens cs := by
  induction cs with
  | nil => rfl
  | cons c cs ih =>
      simp only [tokens, literals_cons, List.map_cons, BinaryNameSearch.stream_cons,
        token_bits, BinaryTokenMachine.tokens_cons, BinaryEncoding.clauseBits]
      simpa only [tokens, List.append_assoc] using
        congrArg (fun tail => BinaryEncoding.literalBits (c)[0] ++
          BinaryEncoding.literalBits (c)[1] ++ BinaryEncoding.literalBits (c)[2] ++ tail) ih

theorem tokens_canonical (cs : List Clause) :
    ∀ t ∈ tokens cs, BinaryNameMachine.canonical t.2 = true := by
  intro t mem
  obtain ⟨literal, _, rfl⟩ := List.mem_map.mp mem
  exact BinaryParsing.canonical_nat_bits literal.name

theorem payload_index (F : Formula) (name : Nat) :
    (BinaryNameSearch.payloads (tokens F.clauses)).idxOf name.bits =
      (sourceNames F).idxOf name := by
  rw [tokens_payloads, BinaryOccurrenceRename.idxOf_binary_payloads]

theorem token_payload_mem (cs : List Clause) (literal : Literal)
    (mem : literal ∈ literals cs) :
    literal.name.bits ∈ BinaryNameSearch.payloads (tokens cs) := by
  apply List.mem_map.mpr
  refine ⟨token literal, ?_, rfl⟩
  exact List.mem_map.mpr ⟨literal, mem, rfl⟩

theorem payloadSize_tokens (cs : List Clause) :
    BinaryNameSearch.payloadSize (tokens cs) = BinaryEncoding.namesBitSize cs := by
  induction cs with
  | nil => rfl
  | cons c cs ih =>
      simp only [tokens, literals_cons, List.map_cons,
        BinaryNameSearch.payloadSize_cons, token, Nat.size_eq_bits_len,
        BinaryEncoding.namesBitSize_cons] at *
      simpa only [BinaryEncoding.clauseNameSize, BinaryFormula.clauseNames,
        List.map_cons, List.map_nil, List.sum_cons, List.sum_nil,
        Nat.add_zero, Nat.add_assoc] using congrArg
        (fun tail => (c)[0].name.size + ((c)[1].name.size + ((c)[2].name.size + tail))) ih

def outputLiteral (names : List Nat) (literal : Literal) : List Bool :=
  Complexity.encodeWord (names.idxOf literal.name) ++
    Complexity.encodeWord (if literal.positive then 1 else 0)

def body (F : Formula) : List Bool :=
  (literals F.clauses).flatMap (outputLiteral (sourceNames F))

theorem encoded_clause (F : Formula) (c : Clause) (mem : c ∈ F.clauses) :
    Complexity.encodeWords (Complexity.clauseWords (BinaryOccurrenceRename.clause F c mem)) =
      (clauseLiterals c).flatMap (outputLiteral (sourceNames F)) := by
  simp [Complexity.clauseWords, Complexity.literalWords, Complexity.encodeWords,
    BinaryOccurrenceRename.clause, BinaryOccurrenceRename.literal,
    BinaryOccurrenceRename.nameIndex, clauseLiterals, outputLiteral, List.append_assoc]
  rfl

private theorem encodeWords_flatMap_inline_MachineBinaryRenameWords {α : Type} (xs : List α) (f : α → List Nat) :
    Complexity.encodeWords (xs.flatMap f) =
      xs.flatMap (fun x => Complexity.encodeWords (f x)) := by
  induction xs with
  | nil => rfl
  | cons x xs ih => simp only [List.flatMap_cons, Complexity.encodeWords_append, ih]

/-- The output contains every literal occurrence, including repetitions. -/
theorem encoded_body (F : Formula) :
    Complexity.encodeWords ((BinaryOccurrenceRename.renamed F).clauses.flatMap
      Complexity.clauseWords) = body F := by
  rw [encodeWords_flatMap_inline_MachineBinaryRenameWords]
  change (F.clauses.attach.map (fun c => BinaryOccurrenceRename.clause F c.val c.property)).flatMap
    (fun c => Complexity.encodeWords (Complexity.clauseWords c)) = body F
  rw [List.flatMap_map]
  simp only [encoded_clause]
  have h := congrArg (fun cs : List Clause =>
    cs.flatMap (fun c => (clauseLiterals c).flatMap (outputLiteral (sourceNames F))))
    (List.attach_map_subtype_val F.clauses)
  simpa only [List.flatMap_map, body, literals, List.flatMap_assoc] using h

/-- Exact ordinary-binary-machine target, including its two count headers. -/
theorem encoded_renamed (F : Formula) :
    Complexity.formulaBits (BinaryOccurrenceRename.renamed F) =
      Complexity.encodeWord (3 * F.clauses.length) ++
        Complexity.encodeWord F.clauses.length ++ body F := by
  simp only [Complexity.formulaBits, Complexity.formulaWords, Complexity.encodeWords_append,
    Complexity.encodeWords, List.append_nil,
    BinaryOccurrenceRename.renamed_variable_count,
    BinaryOccurrenceRename.renamed_clause_count, encoded_body, List.append_assoc]

end MaxCutGames.BinaryRenameWords

/-!
An actual finite Boolean-stack routine prepending two unary header words to an
already restored serialized body. It consumes counters containing `n` and `m`
true bits, respectively, in exactly `n + m + 4` transitions. All ambient stacks
and the finite ambient state are preserved. The input counters need no separate
counting pass: a caller can accumulate them while constructing the body.

The generic placement theorem uses only four displayed instruction equations.
The concrete machine below has three Boolean stacks and four control labels;
its final transfer halts directly. This is a staged configuration computation,
not a single-input `initList` assertion that silently assumes two extra inputs.
-/

namespace MaxCutGames.BinaryHeaderMachine

open Turing
open MaxCutGames.Foundations.Complexity
open MachineComposition
open MaxCutGames.Reduction.MachineTransfer

abbrev Alphabet {K : Type} (_ : K) := Bool
abbrev State (A : Type) := A × Option Bool

section Placement

variable {K Λ A : Type} [DecidableEq K]

/-- A fixed one-bit push; the finite register is cleared before continuation. -/
def delimiter (destination : K) (next : Λ) : TM2.Stmt (Alphabet (K := K)) Λ (State A) :=
  .push destination (fun _ => false)
    (.load (fun state => (state.1, none)) (.goto fun _ => next))

def tapes (variableTape clauses destination : K) (base : K → List Bool)
    (variableCounter clauseCounter output : List Bool) : K → List Bool :=
  Function.update (Function.update (Function.update base variableTape variableCounter)
    clauses clauseCounter) destination output

@[simp] theorem tapes_variables (variableTape clauses destination : K)
    (vc : variableTape ≠ clauses) (vd : variableTape ≠ destination) (base : K → List Bool)
    (variableCounter clauseCounter output : List Bool) :
    tapes variableTape clauses destination base variableCounter clauseCounter output variableTape =
      variableCounter := by
  simp [tapes, vc, vd]

@[simp] theorem tapes_clauses (variableTape clauses destination : K)
    (cd : clauses ≠ destination) (base : K → List Bool)
    (variableCounter clauseCounter output : List Bool) :
    tapes variableTape clauses destination base variableCounter clauseCounter output clauses =
      clauseCounter := by
  simp [tapes, cd]

@[simp] theorem tapes_destination (variableTape clauses destination : K) (base : K → List Bool)
    (variableCounter clauseCounter output : List Bool) :
    tapes variableTape clauses destination base variableCounter clauseCounter output destination =
      output := by
  simp [tapes]

theorem tapes_other (variableTape clauses destination k : K)
    (kv : k ≠ variableTape) (kc : k ≠ clauses) (kd : k ≠ destination)
    (base : K → List Bool) (variableCounter clauseCounter output : List Bool) :
    tapes variableTape clauses destination base variableCounter clauseCounter output k = base k := by
  simp [tapes, kv, kc, kd]

private theorem update_variables_inline_MachineBinaryHeaderMachine (variableTape clauses destination : K)
    (vc : variableTape ≠ clauses) (vd : variableTape ≠ destination) (base : K → List Bool)
    (variableCounter clauseCounter output replacement : List Bool) :
    Function.update (tapes variableTape clauses destination base variableCounter clauseCounter output)
      variableTape replacement = tapes variableTape clauses destination base replacement clauseCounter output := by
  funext k
  by_cases hv : k = variableTape
  · subst k
    simp [tapes, vc, vd]
  · by_cases hd : k = destination
    · subst k
      simp [tapes, hv]
    · by_cases hc : k = clauses
      · subst k
        simp [tapes, hv, hd]
      · simp [tapes, hv, hc, hd]

private theorem update_clauses_inline_MachineBinaryHeaderMachine (variableTape clauses destination : K)
    (cd : clauses ≠ destination) (base : K → List Bool)
    (variableCounter clauseCounter output replacement : List Bool) :
    Function.update (tapes variableTape clauses destination base variableCounter clauseCounter output)
      clauses replacement = tapes variableTape clauses destination base variableCounter replacement output := by
  funext k
  by_cases hc : k = clauses
  · subst k
    simp [tapes, cd]
  · by_cases hd : k = destination
    · subst k
      simp [tapes, hc]
    · simp [tapes, hc, hd]

private theorem update_destination_inline_MachineBinaryHeaderMachine (variableTape clauses destination : K) (base : K → List Bool)
    (variableCounter clauseCounter output replacement : List Bool) :
    Function.update (tapes variableTape clauses destination base variableCounter clauseCounter output)
      destination replacement = tapes variableTape clauses destination base variableCounter clauseCounter replacement := by
  simp [tapes]

variable (variableTape clauses destination : K)
variable (vc : variableTape ≠ clauses) (vd : variableTape ≠ destination) (cd : clauses ≠ destination)
variable (clauseStart clauseLoop variableStart variableLoop : Λ) (exit : Option Λ)
variable (program : Λ → TM2.Stmt (Alphabet (K := K)) Λ (State A))
variable (atClauseStart : program clauseStart = delimiter destination clauseLoop)
variable (atClauseLoop : program clauseLoop =
  loopAt clauses destination id false clauseLoop (some variableStart))
variable (atVariableStart : program variableStart = delimiter destination variableLoop)
variable (atVariableLoop : program variableLoop =
  loopAt variableTape destination id false variableLoop exit)
variable (base : K → List Bool) (ambient : A)

include atClauseStart in
theorem clauseDelimiterStep (variableCounter clauseCounter output : List Bool)
    (register : Option Bool) :
    TM2.step program
      ⟨some clauseStart, (ambient, register),
        tapes variableTape clauses destination base variableCounter clauseCounter output⟩ =
      some ⟨some clauseLoop, (ambient, none),
        tapes variableTape clauses destination base variableCounter clauseCounter (false :: output)⟩ := by
  change some (TM2.stepAux (program clauseStart) _ _) = _
  rw [atClauseStart]
  simp [delimiter, TM2.stepAux, update_destination_inline_MachineBinaryHeaderMachine]

include atVariableStart in
theorem variableDelimiterStep (variableCounter clauseCounter output : List Bool)
    (register : Option Bool) :
    TM2.step program
      ⟨some variableStart, (ambient, register),
        tapes variableTape clauses destination base variableCounter clauseCounter output⟩ =
      some ⟨some variableLoop, (ambient, none),
        tapes variableTape clauses destination base variableCounter clauseCounter (false :: output)⟩ := by
  change some (TM2.stepAux (program variableStart) _ _) = _
  rw [atVariableStart]
  simp [delimiter, TM2.stepAux, update_destination_inline_MachineBinaryHeaderMachine]

include cd atClauseLoop in
theorem clauseCounterTrace (m : Nat) (variableCounter output : List Bool)
    (register : Option Bool) :
    (advance (TM2.step program))^[m + 1]
      (some ⟨some clauseLoop, (ambient, register),
        tapes variableTape clauses destination base variableCounter (List.replicate m true) output⟩) =
      some ⟨some variableStart, (ambient, none),
        tapes variableTape clauses destination base variableCounter [] (List.replicate m true ++ output)⟩ := by
  have h := transferAt_fromTapes (Γ := Alphabet) clauses destination cd id false
    clauseLoop (some variableStart) program atClauseLoop
    (tapes variableTape clauses destination base variableCounter (List.replicate m true) output)
    ambient register
  change (nextAt destination program)^[m + 1]
    (some ⟨some clauseLoop, (ambient, register),
      tapes variableTape clauses destination base variableCounter (List.replicate m true) output⟩) = _
  simpa only [tapes_clauses variableTape clauses destination cd, tapes_destination,
    List.length_replicate, List.reverse_replicate, List.map_id_fun, id_eq,
    tapesAt, update_clauses_inline_MachineBinaryHeaderMachine variableTape clauses destination cd, update_destination_inline_MachineBinaryHeaderMachine,
    nextAt, advance] using h

include vc vd atVariableLoop in
theorem variableCounterTrace (n : Nat) (clauseCounter output : List Bool)
    (register : Option Bool) :
    (advance (TM2.step program))^[n + 1]
      (some ⟨some variableLoop, (ambient, register),
        tapes variableTape clauses destination base (List.replicate n true) clauseCounter output⟩) =
      some ⟨exit, (ambient, none),
        tapes variableTape clauses destination base [] clauseCounter (List.replicate n true ++ output)⟩ := by
  have h := transferAt_fromTapes (Γ := Alphabet) variableTape destination vd id false
    variableLoop exit program atVariableLoop
    (tapes variableTape clauses destination base (List.replicate n true) clauseCounter output)
    ambient register
  change (nextAt destination program)^[n + 1]
    (some ⟨some variableLoop, (ambient, register),
      tapes variableTape clauses destination base (List.replicate n true) clauseCounter output⟩) = _
  simpa only [tapes_variables variableTape clauses destination vc vd, tapes_destination,
    List.length_replicate, List.reverse_replicate, List.map_id_fun, id_eq,
    tapesAt, update_variables_inline_MachineBinaryHeaderMachine variableTape clauses destination vc vd, update_destination_inline_MachineBinaryHeaderMachine,
    nextAt, advance] using h

private theorem joinTrace_inline_MachineBinaryHeaderMachine {X : Type*} {f : X → X} {a b c : X} {n m : Nat}
    (first : f^[n] a = b) (second : f^[m] b = c) : f^[n + m] a = c := by
  rw [Nat.add_comm, Function.iterate_add_apply, first, second]

include vc vd cd atClauseStart atClauseLoop atVariableStart atVariableLoop

/-- The actual four-phase routine, with exact unary header and preserved body. -/
theorem headerTrace (n m : Nat) (body : List Bool) (register : Option Bool) :
    (advance (TM2.step program))^[n + m + 4]
      (some ⟨some clauseStart, (ambient, register),
        tapes variableTape clauses destination base
          (List.replicate n true) (List.replicate m true) body⟩) =
      some ⟨exit, (ambient, none),
        tapes variableTape clauses destination base [] [] (encodeWord n ++ encodeWord m ++ body)⟩ := by
  have first := clauseDelimiterStep variableTape clauses destination clauseStart clauseLoop program
    atClauseStart base ambient (List.replicate n true) (List.replicate m true) body register
  change (advance (TM2.step program))^[1]
    (some ⟨some clauseStart, (ambient, register),
      tapes variableTape clauses destination base (List.replicate n true) (List.replicate m true) body⟩) = _ at first
  have second := clauseCounterTrace variableTape clauses destination cd clauseLoop variableStart program
    atClauseLoop base ambient m (List.replicate n true) (false :: body) none
  have third := variableDelimiterStep variableTape clauses destination variableStart variableLoop program
    atVariableStart base ambient (List.replicate n true) []
    (List.replicate m true ++ false :: body) none
  change (advance (TM2.step program))^[1]
    (some ⟨some variableStart, (ambient, none),
      tapes variableTape clauses destination base (List.replicate n true) []
        (List.replicate m true ++ false :: body)⟩) = _ at third
  have fourth := variableCounterTrace variableTape clauses destination vc vd variableLoop exit program
    atVariableLoop base ambient n [] (false :: (List.replicate m true ++ false :: body)) none
  have full := joinTrace_inline_MachineBinaryHeaderMachine (joinTrace_inline_MachineBinaryHeaderMachine (joinTrace_inline_MachineBinaryHeaderMachine first second) third) fourth
  have htime : ((1 + (m + 1)) + 1) + (n + 1) = n + m + 4 := by omega
  rw [htime] at full
  simpa only [encodeWord, List.append_assoc, List.singleton_append,
    List.cons_append, List.nil_append] using full

def headerInTime (n m : Nat) (body : List Bool) (register : Option Bool) :
    StateTransition.EvalsToInTime (TM2.step program)
      ⟨some clauseStart, (ambient, register),
        tapes variableTape clauses destination base (List.replicate n true) (List.replicate m true) body⟩
      (some ⟨exit, (ambient, none),
        tapes variableTape clauses destination base [] [] (encodeWord n ++ encodeWord m ++ body)⟩)
      (n + m + 4) where
  steps := n + m + 4
  evals_in_steps := headerTrace variableTape clauses destination vc vd cd
    clauseStart clauseLoop variableStart variableLoop exit program
    atClauseStart atClauseLoop atVariableStart atVariableLoop base ambient n m body register
  steps_le_m := Nat.le_refl _

end Placement

abbrev ConcreteTape := Fin 3
abbrev ConcreteLabel := Fin 4

def concreteProgram (label : ConcreteLabel) :
    TM2.Stmt (Alphabet (K := ConcreteTape)) ConcreteLabel (State Unit) :=
  if label = 0 then delimiter 2 1
  else if label = 1 then loopAt 1 2 id false 1 (some 2)
  else if label = 2 then delimiter 2 3
  else loopAt 0 2 id false 3 none

abbrev machine : FinTM2 where
  K := ConcreteTape
  k₀ := 0
  k₁ := 2
  Γ := Alphabet
  Λ := ConcreteLabel
  main := 0
  σ := State Unit
  initialState := ((), none)
  m := concreteProgram

/-- Concrete entry configuration carries two physical counters and the body. -/
def start (n m : Nat) (body : List Bool) : machine.Cfg :=
  ⟨some 0, ((), none),
    tapes 0 1 2 (fun _ : ConcreteTape => []) (List.replicate n true) (List.replicate m true) body⟩

theorem haltList_eq (body : List Bool) :
    haltList machine body =
      ⟨none, ((), none), tapes 0 1 2 (fun _ : ConcreteTape => []) [] [] body⟩ := by
  unfold haltList
  congr 1
  funext k
  fin_cases k <;> simp [machine, tapes]

/-- Genuine staged execution of the concrete four-label finite machine. -/
def machineInTime (n m : Nat) (body : List Bool) :
    StateTransition.EvalsToInTime machine.step (start n m body)
      (some (haltList machine (encodeWord n ++ encodeWord m ++ body))) (n + m + 4) := by
  rw [haltList_eq]
  exact headerInTime (0 : ConcreteTape) 1 2 (by decide) (by decide) (by decide)
    (0 : ConcreteLabel) 1 2 3 none concreteProgram
    (by simp [concreteProgram]) (by simp [concreteProgram])
    (by simp [concreteProgram]) (by simp [concreteProgram])
    (fun _ => []) () n m body none

theorem machine_finiteAlphabet (k : machine.K) : Finite (machine.Γ k) := by
  change Finite Bool
  infer_instance

end MaxCutGames.BinaryHeaderMachine

/-!
The finite Boolean-stack driver for first-occurrence renaming. Its permanent
input is copied to a cursor, each literal is translated by the checked search
loop, and the physical output is restored, prefixed with its count headers,
and cleaned up. Every tape uses Bool and every control component is finite.
-/

namespace MaxCutGames.BinaryRenameMachine

open Turing MaxCutGames.Foundations
open Complexity Complexity.MachineComposition
open MaxCutGames.Reduction.MachineTransfer

abbrev Tape := Fin 12
abbrev Alphabet (_ : Tape) := Bool
abbrev State := BinaryRenameLoop.State Unit

inductive Label
  | copyOut | copyBack
  | loop (label : BinaryRenameLoop.Label)
  | restore | clauseStart | clauseLoop | variableStart | variableLoop
  | cleanup | reject
  deriving DecidableEq, Fintype

def loopTapes : Fin 11 → Tape := Fin.castSucc

theorem loopTapes_injective : Function.Injective loopTapes := by
  intro i j h
  apply Fin.ext
  exact congrArg (fun k : Tape => k.val) h

def program : Label → TM2.Stmt Alphabet Label State
  | .copyOut => loopAt 1 6 id false .copyOut (some .copyBack)
  | .copyBack => MachineCopy.forkLoop 6 1 0 false .copyBack (some (.loop .entry))
  | .loop label => BinaryRenameLoop.instruction loopTapes Label.loop
      (some .restore) (some .reject) label
  | .restore => loopAt 8 11 id false .restore (some .clauseStart)
  | .clauseStart => BinaryHeaderMachine.delimiter 11 .clauseLoop
  | .clauseLoop => loopAt 10 11 id false .clauseLoop (some .variableStart)
  | .variableStart => BinaryHeaderMachine.delimiter 11 .variableLoop
  | .variableLoop => loopAt 9 11 id false .variableLoop (some .cleanup)
  | .cleanup => MachineDrain.drain 1 .cleanup none
  | .reject => .halt

abbrev machine : FinTM2 where
  K := Tape
  k₀ := 1
  k₁ := 11
  Γ := Alphabet
  Λ := Label
  main := .copyOut
  σ := State
  initialState := BinaryRenameLoop.clean () 0
  m := program

def tapes (permanent cursor reversed variableCounter clauseCounter output : List Bool) :
    Tape → List Bool := fun k =>
  if k = 0 then cursor
  else if k = 1 then permanent
  else if k = 8 then reversed
  else if k = 9 then variableCounter
  else if k = 10 then clauseCounter
  else if k = 11 then output
  else []

def cfg (label : Option Label)
    (permanent cursor reversed variableCounter clauseCounter output : List Bool) : machine.Cfg :=
  ⟨label, BinaryRenameLoop.clean () 0,
    tapes permanent cursor reversed variableCounter clauseCounter output⟩

theorem initList_eq (input : List Bool) :
    initList machine input = cfg (some .copyOut) input [] [] [] [] [] := by
  unfold initList cfg
  congr 1
  funext k
  fin_cases k <;> simp [tapes, machine]

theorem haltList_eq (output : List Bool) :
    haltList machine output = cfg none [] [] [] [] [] output := by
  unfold haltList cfg
  congr 1
  funext k
  fin_cases k <;> simp [tapes, machine]

theorem copyTrace (input : List Bool) :
    (advance machine.step)^[2 * (input.length + 1)]
      (some (cfg (some .copyOut) input [] [] [] [] [])) =
      some (cfg (some (.loop .entry)) input input [] [] [] []) := by
  have updated : Function.update (tapes input [] [] [] [] []) 0 input =
      tapes input input [] [] [] [] := by
    funext k
    fin_cases k <;> simp [tapes]
  have h := MachineCopy.copyTrace (1 : Tape) 0 6 (by decide) (by decide) (by decide)
    false .copyOut .copyBack (some (.loop .entry)) program rfl rfl
    (tapes input [] [] [] [] []) (by simp [tapes])
    (BinaryRenameLoop.clean () 0).1 none
  have first : tapes input [] [] [] [] [] 1 = input := rfl
  have second : tapes input [] [] [] [] [] 0 = [] := rfl
  rw [first, second, List.append_nil, updated] at h
  exact h

theorem restoreTrace (input body variableCounter clauseCounter : List Bool) :
    (advance machine.step)^[body.length + 1]
      (some (cfg (some .restore) input [] body.reverse variableCounter clauseCounter [])) =
      some (cfg (some .clauseStart) input [] [] variableCounter clauseCounter body) := by
  change (nextAt (11 : Tape) program)^[body.length + 1]
    (some (cfg (some .restore) input [] body.reverse variableCounter clauseCounter [])) = _
  have updated : tapesAt (8 : Tape) 11
      (tapes input [] body.reverse variableCounter clauseCounter []) [] body =
      tapes input [] [] variableCounter clauseCounter body := by
    funext k
    fin_cases k <;> simp [tapesAt, tapes]
  have h := transferAt_fromTapes (Γ := Alphabet) (8 : Tape) 11 (by decide) id false
    .restore (some .clauseStart) program rfl
    (tapes input [] body.reverse variableCounter clauseCounter [])
    (BinaryRenameLoop.clean () 0).1 none
  have source : tapes input [] body.reverse variableCounter clauseCounter [] 8 = body.reverse := rfl
  have output : tapes input [] body.reverse variableCounter clauseCounter [] 11 = [] := rfl
  rw [source, output, List.length_reverse, List.reverse_reverse, List.map_id_fun,
    List.append_nil, id_eq, updated] at h
  exact h

theorem headerTrace (input body : List Bool) (n m : Nat) :
    (advance machine.step)^[n + m + 4]
      (some (cfg (some .clauseStart) input [] []
        (List.replicate n true) (List.replicate m true) body)) =
      some (cfg (some .cleanup) input [] [] [] []
        (encodeWord n ++ encodeWord m ++ body)) := by
  change (advance (TM2.step program))^[n + m + 4]
    (some ⟨some .clauseStart, ((BinaryRenameLoop.clean () 0).1, none),
      tapes input [] [] (List.replicate n true) (List.replicate m true) body⟩) =
    some ⟨some .cleanup, ((BinaryRenameLoop.clean () 0).1, none),
      tapes input [] [] [] [] (encodeWord n ++ encodeWord m ++ body)⟩
  have updated (variableWord clauses output : List Bool) :
      BinaryHeaderMachine.tapes (9 : Tape) 10 11 (tapes input [] [] [] [] [])
        variableWord clauses output = tapes input [] [] variableWord clauses output := by
    funext k
    fin_cases k <;> simp [BinaryHeaderMachine.tapes, tapes]
  have h := BinaryHeaderMachine.headerTrace (9 : Tape) 10 11
    (by decide) (by decide) (by decide)
    .clauseStart .clauseLoop .variableStart .variableLoop (some .cleanup) program
    rfl rfl rfl rfl (tapes input [] [] [] [] [])
    (BinaryRenameLoop.clean () 0).1 n m body none
  simp only [updated] at h
  exact h

theorem cleanupTrace (input output : List Bool) :
    (advance machine.step)^[input.length + 1]
      (some (cfg (some .cleanup) input [] [] [] [] output)) =
      some (cfg none [] [] [] [] [] output) := by
  change (advance (TM2.step program))^[input.length + 1]
    (some ⟨some .cleanup, ((BinaryRenameLoop.clean () 0).1, none),
      tapes input [] [] [] [] output⟩) =
    some ⟨none, ((BinaryRenameLoop.clean () 0).1, none), tapes [] [] [] [] [] output⟩
  have updated (word : List Bool) :
      Function.update (tapes [] [] [] [] [] output) 1 word =
        tapes word [] [] [] [] output := by
    funext k
    fin_cases k <;> simp [tapes]
  have h := MachineDrain.drainTrace (1 : Tape) .cleanup none program rfl
    (tapes [] [] [] [] [] output) input (BinaryRenameLoop.clean () 0).1 none
  simp only [updated] at h
  exact h

theorem outputBody_eq (formula : BinaryFormula.Formula) :
    BinaryRenameLoop.outputBody (BinaryRenameWords.tokens formula.clauses)
      (BinaryRenameWords.tokens formula.clauses) = BinaryRenameWords.body formula := by
  change ((BinaryRenameWords.literals formula.clauses).map BinaryRenameWords.token).flatMap
    (fun t => BinaryLiteralMachine.outputWord (BinaryRenameWords.tokens formula.clauses)
      t.2 t.1) = (BinaryRenameWords.literals formula.clauses).flatMap
        (BinaryRenameWords.outputLiteral (BinaryFormula.sourceNames formula))
  rw [List.flatMap_map]
  apply List.flatMap_congr
  intro literal _
  simp only [BinaryRenameWords.token, BinaryLiteralMachine.outputWord,
    BinaryLiteralMachine.index, BinaryLiteralMachine.signWord,
    BinaryRenameWords.payload_index, BinaryRenameWords.outputLiteral]
  rfl

theorem loopTrace (formula : BinaryFormula.Formula) :
    (advance machine.step)^[BinaryRenameLoop.steps (BinaryRenameWords.tokens formula.clauses)
        (BinaryRenameWords.tokens formula.clauses)]
      (some (cfg (some (.loop .entry)) (BinaryTokenMachine.tokens formula.clauses)
        (BinaryTokenMachine.tokens formula.clauses) [] [] [] [])) =
      some (cfg (some .restore) (BinaryTokenMachine.tokens formula.clauses) []
        (BinaryRenameWords.body formula).reverse (List.replicate (3 * formula.clauses.length) true)
        (List.replicate formula.clauses.length true) []) := by
  change (advance (TM2.step program))^[BinaryRenameLoop.steps
      (BinaryRenameWords.tokens formula.clauses) (BinaryRenameWords.tokens formula.clauses)]
    (some ⟨some (.loop .entry), BinaryRenameLoop.clean () 0,
      tapes (BinaryTokenMachine.tokens formula.clauses) (BinaryTokenMachine.tokens formula.clauses)
        [] [] [] []⟩) =
    some ⟨some .restore, BinaryRenameLoop.clean () 0,
      tapes (BinaryTokenMachine.tokens formula.clauses) [] (BinaryRenameWords.body formula).reverse
        (List.replicate (3 * formula.clauses.length) true)
        (List.replicate formula.clauses.length true) []⟩
  let input := BinaryTokenMachine.tokens formula.clauses
  have updated (cursor output variableWord clauseWord : List Bool) :
      BinaryRenameLoop.loopTapes loopTapes (tapes input [] [] [] [] [])
        cursor output variableWord clauseWord =
      tapes input cursor output variableWord clauseWord [] := by
    funext k
    fin_cases k <;> simp [BinaryRenameLoop.loopTapes, loopTapes, tapes]
  have scratch (i : Fin 11) (lo : 2 ≤ i.val) (hi : i.val ≤ 7) :
      tapes input [] [] [] [] [] (loopTapes i) = [] := by
    have n0 : loopTapes i ≠ 0 := by intro h; have := congrArg Fin.val h; simp [loopTapes] at this; omega
    have n1 : loopTapes i ≠ 1 := by intro h; have := congrArg Fin.val h; simp [loopTapes] at this; omega
    have n8 : loopTapes i ≠ 8 := by intro h; have := congrArg Fin.val h; simp [loopTapes] at this; omega
    have n9 : loopTapes i ≠ 9 := by intro h; have := congrArg Fin.val h; simp [loopTapes] at this; omega
    have n10 : loopTapes i ≠ 10 := by intro h; have := congrArg Fin.val h; simp [loopTapes] at this; omega
    have n11 : loopTapes i ≠ 11 := by intro h; have := congrArg Fin.val h; simp [loopTapes] at this; omega
    simp [tapes, n0, n1, n8, n9, n10, n11]
  have run := BinaryRenameLoop.triplesTrace loopTapes loopTapes_injective Label.loop
    (some .restore) (some .reject) program (fun _ => rfl)
    (tapes input [] [] [] [] []) ()
    (BinaryRenameWords.tokens formula.clauses) (BinaryRenameWords.tokens formula.clauses)
    formula.clauses.length (BinaryRenameWords.tokens_length formula.clauses) [] [] []
    (BinaryRenameWords.tokens_canonical formula.clauses) (fun _ h => h)
    (by change input = _; rw [BinaryRenameWords.tokens_stream]) scratch
  simp only [updated, BinaryRenameWords.tokens_stream, outputBody_eq, List.append_nil, input] at run
  exact run

private theorem joinTrace_inline_MachineBinaryRenameMachine {X : Type*} {f : X → X} {a b c : X} {n m : Nat}
    (first : f^[n] a = b) (second : f^[m] b = c) : f^[n + m] a = c := by
  rw [Nat.add_comm, Function.iterate_add_apply, first, second]

def steps (formula : BinaryFormula.Formula) : Nat :=
  2 * ((BinaryTokenMachine.tokens formula.clauses).length + 1) +
    BinaryRenameLoop.steps (BinaryRenameWords.tokens formula.clauses)
      (BinaryRenameWords.tokens formula.clauses) +
    ((BinaryRenameWords.body formula).length + 1) + (4 * formula.clauses.length + 4) +
    ((BinaryTokenMachine.tokens formula.clauses).length + 1)

theorem renameTrace (formula : BinaryFormula.Formula) :
    (advance machine.step)^[steps formula]
      (some (initList machine (BinaryTokenMachine.tokens formula.clauses))) =
      some (haltList machine (formulaBits (BinaryOccurrenceRename.renamed formula))) := by
  have first := copyTrace (BinaryTokenMachine.tokens formula.clauses)
  have second := loopTrace formula
  have third := restoreTrace (BinaryTokenMachine.tokens formula.clauses)
    (BinaryRenameWords.body formula) (List.replicate (3 * formula.clauses.length) true)
    (List.replicate formula.clauses.length true)
  have fourth := headerTrace (BinaryTokenMachine.tokens formula.clauses)
    (BinaryRenameWords.body formula) (3 * formula.clauses.length) formula.clauses.length
  have fifth := cleanupTrace (BinaryTokenMachine.tokens formula.clauses)
    (encodeWord (3 * formula.clauses.length) ++ encodeWord formula.clauses.length ++
      BinaryRenameWords.body formula)
  have full := joinTrace_inline_MachineBinaryRenameMachine (joinTrace_inline_MachineBinaryRenameMachine (joinTrace_inline_MachineBinaryRenameMachine (joinTrace_inline_MachineBinaryRenameMachine first second) third) fourth) fifth
  have count : 3 * formula.clauses.length + formula.clauses.length + 4 =
      4 * formula.clauses.length + 4 := by omega
  simpa only [steps, initList_eq, haltList_eq, BinaryRenameWords.encoded_renamed, count] using full

theorem clause_count_le_stream (formula : BinaryFormula.Formula) :
    formula.clauses.length ≤ (BinaryTokenMachine.tokens formula.clauses).length := by
  rw [BinaryTokenMachine.tokens_length]
  omega

theorem body_length_le (formula : BinaryFormula.Formula) :
    (BinaryRenameWords.body formula).length ≤
      9 * (BinaryTokenMachine.tokens formula.clauses).length ^ 2 +
        10 * (BinaryTokenMachine.tokens formula.clauses).length + 2 := by
  have initial := BinaryOccurrenceRename.renamed_encoding_bound formula
  rw [BinaryRenameWords.encoded_renamed] at initial
  simp only [List.length_append] at initial
  have count := clause_count_le_stream formula
  have square := Nat.mul_self_le_mul_self count
  nlinarith

noncomputable def timePolynomial : Polynomial Nat :=
  Polynomial.C 12 * Polynomial.X ^ 3 + Polynomial.C 35 * Polynomial.X ^ 2 +
    Polynomial.C 28 * Polynomial.X + Polynomial.C 11

theorem steps_le (formula : BinaryFormula.Formula) :
    steps formula ≤ timePolynomial.eval (BinaryTokenMachine.tokens formula.clauses).length := by
  have loopBound := BinaryRenameLoop.steps_le
    (BinaryRenameWords.tokens formula.clauses) (BinaryRenameWords.tokens formula.clauses)
    (fun _ h => h)
  rw [BinaryRenameWords.tokens_stream, BinaryRenameWords.tokens_length] at loopBound
  have literalCount : 3 * formula.clauses.length ≤
      (BinaryTokenMachine.tokens formula.clauses).length := by
    rw [BinaryTokenMachine.tokens_length]
    omega
  have product := Nat.mul_le_mul_left
    (BinaryRenameLoop.perLiteralBound (BinaryTokenMachine.tokens formula.clauses).length)
    literalCount
  have output := body_length_le formula
  have count := clause_count_le_stream formula
  simp only [timePolynomial, Polynomial.eval_add, Polynomial.eval_mul, Polynomial.eval_pow,
    Polynomial.eval_C, Polynomial.eval_X]
  unfold steps BinaryRenameLoop.perLiteralBound at *
  nlinarith

def outputsInTime (formula : BinaryFormula.Formula) :
    TM2OutputsInTime machine (BinaryTokenMachine.tokens formula.clauses)
      (some (formulaBits (BinaryOccurrenceRename.renamed formula)))
      (timePolynomial.eval (BinaryTokenMachine.tokens formula.clauses).length) where
  steps := steps formula
  evals_in_steps := renameTrace formula
  steps_le_m := steps_le formula

/-- The token-stream phase has a displayed finite machine and actual execution
bound; its polynomial argument is the token stream's physical bit length. -/
noncomputable def tokenComputation :
    TM2ComputableInPolyTime (fun formula : BinaryFormula.Formula =>
      BinaryTokenMachine.tokens formula.clauses) formulaBits BinaryOccurrenceRename.renamed where
  tm := machine
  inputAlphabet := Equiv.refl Bool
  outputAlphabet := Equiv.refl Bool
  time := timePolynomial
  outputsFun formula := by
    change TM2OutputsInTime machine ((BinaryTokenMachine.tokens formula.clauses).map id)
      (some ((formulaBits (BinaryOccurrenceRename.renamed formula)).map id))
      (timePolynomial.eval (BinaryTokenMachine.tokens formula.clauses).length)
    simpa only [List.map_id_fun, id_eq] using outputsInTime formula

/-- Repackage the checked marker-removal machine without changing any machine
or word: the intermediate semantic value is the same formula. -/
noncomputable def preprocessing :
    TM2ComputableInPolyTime BinaryEncoding.formulaBits
      (fun formula : BinaryFormula.Formula => BinaryTokenMachine.tokens formula.clauses)
      (id : BinaryFormula.Formula → BinaryFormula.Formula) where
  tm := BinaryTokenMachine.computableInPolyTime.tm
  inputAlphabet := BinaryTokenMachine.computableInPolyTime.inputAlphabet
  outputAlphabet := BinaryTokenMachine.computableInPolyTime.outputAlphabet
  time := BinaryTokenMachine.computableInPolyTime.time
  outputsFun := BinaryTokenMachine.computableInPolyTime.outputsFun

/-- Actual finite-alphabet polynomial-time sparse binary to dense unary
renaming. Sparse name magnitudes are never expanded in unary. -/
noncomputable def computableInPolyTime :
    TM2ComputableInPolyTime BinaryEncoding.formulaBits formulaBits
      BinaryOccurrenceRename.renamed :=
  MachineSequential.composeBits preprocessing tokenComputation

theorem machine_finiteAlphabet (k : machine.K) : Finite (machine.Γ k) := by
  change Finite Bool
  infer_instance

theorem computation_finiteAlphabet : MachineFiniteAlphabet.FiniteAlphabet computableInPolyTime.tm :=
  MachineFiniteAlphabet.composeBits preprocessing tokenComputation
    BinaryTokenMachine.machine_finiteAlphabet machine_finiteAlphabet

end MaxCutGames.BinaryRenameMachine

end OAI