import Mathlib
import OAI.Combinatorics.IndependentSets.Expansion.PoweringTables

namespace OAI

namespace IndependentSetsGames.Foundations.PCP.PoweringTableSemantics

open PoweringWalks PoweringLabels PoweringAddresses PoweringEnumeration PoweringTables

abbrev RawLabeling (vertices d n : Nat) :=
  Fin vertices → PaddedLabel (Fin d) (n + 1) (Fin 64)

abbrev EncodedLabeling (vertices d n : Nat) :=
  Fin vertices → Fin (labelCount d n)

def encodeLabeling {vertices : Nat} (d n : Nat) (labels : RawLabeling vertices d n) :
    EncodedLabeling vertices d n :=
  fun v => encodeLabel d (n + 1) 64 (labels v)

def decodeLabeling {vertices : Nat} (d n : Nat) (labels : EncodedLabeling vertices d n) :
    RawLabeling vertices d n :=
  fun v => decodeLabel d (n + 1) 64 (labels v)

@[simp] theorem decodeLabeling_encodeLabeling {vertices : Nat} (d n : Nat)
    (labels : RawLabeling vertices d n) :
    decodeLabeling d n (encodeLabeling d n labels) = labels := by
  funext v
  exact decodeLabel_encodeLabel d (n + 1) 64 (labels v)

@[simp] theorem encodeLabeling_decodeLabeling {vertices : Nat} (d n : Nat)
    (labels : EncodedLabeling vertices d n) :
    encodeLabeling d n (decodeLabeling d n labels) = labels := by
  funext v
  exact encodeLabel_decodeLabel d (n + 1) 64 (labels v)

theorem edgeSatisfied_encoded {vertices d : Nat} (input : PortTables.Table vertices d)
    (n : Nat) (labels : RawLabeling vertices d n)
    (e : PoweringTest.Dart (Fin vertices) (Fin d) n) :
    (GenericGraphTables.semantics (table input n)).edgeSatisfied
      (encodeLabeling (vertices := vertices) d n labels) (encodeDart vertices d n e) =
        (mathematicalGraph input n).edgeSatisfied labels e := by
  rw [semantics_table]
  unfold encodeLabeling encodeLabel encodeDart
  exact
    GenericGraphTables.enumeratedGraph_edgeSatisfied (mathematicalGraph input n)
      (Equiv.refl _) (dartEquiv vertices d n) (paddedLabelEquiv d (n + 1) 64) labels e

theorem edgeSatisfied_decoded {vertices d : Nat} (input : PortTables.Table vertices d)
    (n : Nat) (labels : EncodedLabeling vertices d n) (i : Fin (dartCount vertices d n)) :
    (GenericGraphTables.semantics (table input n)).edgeSatisfied labels i =
      (mathematicalGraph input n).edgeSatisfied (decodeLabeling d n labels)
        (decodeDart vertices d n i) := by
  simpa only [encodeLabeling_decodeLabeling d n labels,
    encodeDart_decodeDart vertices d n i] using
    edgeSatisfied_encoded input n (decodeLabeling d n labels) (decodeDart vertices d n i)

theorem edgeSatisfied_eq_path {vertices d : Nat} (input : PortTables.Table vertices d)
    (n : Nat) (labels : EncodedLabeling vertices d n) (direction : Bool)
    (w : Walk (Fin vertices) (Fin d) (n + 1)) :
    (GenericGraphTables.semantics (table input n)).edgeSatisfied labels
      (encodeDart vertices d n (direction, w)) =
    PoweringTest.pathAccepts (PortTables.portGraph input) (PortTables.accepts input) n
      (finitePortSelector (PortTables.portGraph input) (n + 1)) w
      (decodeLabeling d n labels w.1)
      (decodeLabeling d n labels (endpoint (PortTables.portGraph input) w)) := by
  rw [edgeSatisfied_decoded input n labels (encodeDart vertices d n (direction, w)),
    decodeDart_encodeDart vertices d n (direction, w)]
  exact PoweringTest.poweredGraph_edgeSatisfied (PortTables.portGraph input)
    (PortTables.accepts input) n (finitePortSelector (PortTables.portGraph input) (n + 1))
    (decodeLabeling d n labels) direction w

theorem rejectionCount_encoded {vertices d : Nat} (input : PortTables.Table vertices d)
    (n : Nat) (labels : RawLabeling vertices d n) :
    (GenericGraphTables.semantics (table input n)).rejectionCount
      (encodeLabeling (vertices := vertices) d n labels) =
        (mathematicalGraph input n).rejectionCount labels := by
  rw [semantics_table]
  unfold encodeLabeling encodeLabel
  exact
    GenericGraphTables.enumeratedGraph_rejectionCount (mathematicalGraph input n)
      (Equiv.refl _) (dartEquiv vertices d n) (paddedLabelEquiv d (n + 1) 64) labels

theorem rejectionCount_decoded {vertices d : Nat} (input : PortTables.Table vertices d)
    (n : Nat) (labels : EncodedLabeling vertices d n) :
    (GenericGraphTables.semantics (table input n)).rejectionCount labels =
      (mathematicalGraph input n).rejectionCount (decodeLabeling d n labels) := by
  simpa only [encodeLabeling_decodeLabeling d n labels] using
    rejectionCount_encoded input n (decodeLabeling d n labels)

theorem card_darts_eq_table {vertices d : Nat} (input : PortTables.Table vertices d)
    (n : Nat) :
    Fintype.card (PoweringTest.Dart (Fin vertices) (Fin d) n) = (table input n).darts := by
  change Fintype.card (PoweringTest.Dart (Fin vertices) (Fin d) n) =
    2 * vertices * d ^ (n + 1)
  simpa only [Fintype.card_fin] using Fintype.card_congr (dartEquiv vertices d n)

theorem satisfiable_iff {vertices d : Nat} (input : PortTables.Table vertices d) (n : Nat) :
    (GenericGraphTables.semantics (table input n)).Satisfiable ↔
      (mathematicalGraph input n).Satisfiable := by
  constructor
  · rintro ⟨labels, satisfies⟩
    refine ⟨decodeLabeling d n labels, ?_⟩
    intro e
    have h := edgeSatisfied_encoded input n (decodeLabeling d n labels) e
    rw [encodeLabeling_decodeLabeling (vertices := vertices) d n labels] at h
    exact h.symm.trans (satisfies (encodeDart vertices d n e))
  · rintro ⟨labels, satisfies⟩
    refine ⟨encodeLabeling d n labels, ?_⟩
    intro i
    have h := edgeSatisfied_encoded input n labels (decodeDart vertices d n i)
    rw [encodeDart_decodeDart vertices d n i] at h
    exact h.trans (satisfies (decodeDart vertices d n i))

theorem preserves_satisfiability {vertices d : Nat} (input : PortTables.Table vertices d)
    (n : Nat) (h : (PortTables.baseGraph input).Satisfiable) :
    (GenericGraphTables.semantics (table input n)).Satisfiable := by
  apply (satisfiable_iff input n).mpr
  exact PoweringTest.preserves_satisfiability (PortTables.portGraph input)
    (PortTables.accepts input) (PortTables.accepts_rotation input) n
    (finitePortSelector (PortTables.portGraph input) (n + 1)) h

theorem path_rejection_mean_eq_table_fraction {vertices d : Nat}
    (input : PortTables.Table vertices d) (n : Nat) (labels : EncodedLabeling vertices d n) :
    SpectralReturn.mean (fun w : Walk (Fin vertices) (Fin d) (n + 1) =>
      PoweringMoment.bit
        (PoweringTest.pathAccepts (PortTables.portGraph input) (PortTables.accepts input) n
          (finitePortSelector (PortTables.portGraph input) (n + 1)) w
          (decodeLabeling d n labels w.1)
          (decodeLabeling d n labels (endpoint (PortTables.portGraph input) w)) = false)) =
      ((GenericGraphTables.semantics (table input n)).rejectionCount labels : ℝ) /
        ((table input n).darts : ℝ) := by
  rw [rejectionCount_decoded input n labels, ← card_darts_eq_table input n]
  exact PoweringCounting.path_rejection_mean_eq_count (PortTables.portGraph input)
    (PortTables.accepts input) n (finitePortSelector (PortTables.portGraph input) (n + 1))
    (decodeLabeling d n labels)

theorem uniform_count_gap_iff {vertices d : Nat} (input : PortTables.Table vertices d)
    (n : Nat) (epsilon : ℝ) :
    (∀ labels : EncodedLabeling vertices d n,
      epsilon * ((table input n).darts : ℝ) ≤
        ((GenericGraphTables.semantics (table input n)).rejectionCount labels : ℝ)) ↔
    (∀ labels : RawLabeling vertices d n,
      epsilon * (Fintype.card (PoweringTest.Dart (Fin vertices) (Fin d) n) : ℝ) ≤
        ((mathematicalGraph input n).rejectionCount labels : ℝ)) := by
  constructor
  · intro h labels
    have hlabels := h (encodeLabeling d n labels)
    rw [rejectionCount_encoded input n labels, ← card_darts_eq_table input n] at hlabels
    exact hlabels
  · intro h labels
    rw [rejectionCount_decoded input n labels]
    have hlabels := h (decodeLabeling d n labels)
    rw [card_darts_eq_table input n] at hlabels
    exact hlabels

theorem uniform_count_gap {vertices d : Nat} (input : PortTables.Table vertices d)
    (n : Nat) (epsilon : ℝ)
    (hgap : ∀ labels : RawLabeling vertices d n,
      epsilon * (Fintype.card (PoweringTest.Dart (Fin vertices) (Fin d) n) : ℝ) ≤
        ((mathematicalGraph input n).rejectionCount labels : ℝ)) :
    ∀ labels : EncodedLabeling vertices d n,
      epsilon * ((table input n).darts : ℝ) ≤
        ((GenericGraphTables.semantics (table input n)).rejectionCount labels : ℝ) :=
  (uniform_count_gap_iff input n epsilon).mpr hgap

end IndependentSetsGames.Foundations.PCP.PoweringTableSemantics

end OAI