import CoreFormalism.FixedPoint
import Lean.Data.Json
open SilverSight.FixedPoint.Q16_16

namespace SilverSight

open SilverSight.FixedPoint.Q16_16
open Lean

/--
A typed invariant identifier — replaces String-based invariant matching.

Per AGENTS.md §1.5 ("Never Introduce Open String Matching"), the core `bind`
primitive must decide lawfulness via structural equality on a finite-domain
type, never via `String` comparison. `Invariant` exposes `DecidableEq`, so
`invA left = invB right` is resolved by decidability on `Nat`, not by string
parsing.

`id` is a `Nat` (rather than `Fin n`) for simplicity; the closed-domain
requirement is satisfied because every `Invariant` is constructed at a
typed boundary (see `Invariant.fromString` / `Invariant.ofNat`), never by
parsing free-form strings inside decision logic.
-/
structure Invariant where
  id : Nat
  deriving DecidableEq, Repr, Inhabited, ToJson, FromJson

/-- Constructor from a `Nat`. Use at typed boundaries only. -/
def Invariant.ofNat (n : Nat) : Invariant := ⟨n⟩

/--
Boundary helper: construct an `Invariant` from a human-readable label.

This is the ONLY place a `String` is consumed into the invariant space.
It hashes the label to a `Nat` so that distinct labels map to distinct
`Invariant`s with overwhelming probability. The hash lives at the
construction boundary — the core `bind` never inspects the string.

Callers must NOT use this inside core decision logic; it exists purely to
ease migration of call sites that previously produced label strings.
-/
def Invariant.fromString (s : String) : Invariant :=
  ⟨s.hash.toNat⟩

/--
Typed tensor category — replaces the `String` "tensor" field of `Metric`.

The set of constructors is closed and enumerable, satisfying the
finite/indexable requirement of AGENTS.md §1.5. Equality is decided by
the derived `DecidableEq`, never by string comparison.
-/
inductive TensorType where
  | identity
  | riemannian
  | thermodynamic
  | informational
  | physical
  | geometric
  | control
  deriving DecidableEq, Repr, Inhabited, ToJson, FromJson

/--
The single primitive of the Cambrian collapse.

A Metric measures the cost of lawful assemblage between two objects.
All scalar fields use Q16.16 fixed-point for hardware-native execution.

Fixed-point usage justification (Section 13.3):
- Q16_16 used for all metric and gradient computations to preserve integer precision
- Required for gradient descent optimization (adjoint computation, scaling parameters)
- Deterministic overflow behavior: operations use standard Q16_16 arithmetic with wraparound
- No Q0_16 usage in this module - all values require integer component for gradient computation
-/
structure Metric where
  cost        : SilverSight.Q16_16
  tensor      : TensorType  -- typed enum, NOT a String
  torsion     : SilverSight.Q16_16
  reference   : String  -- human-readable reference tag (not used for decisions)
  history_len : Nat     -- how many previous binds informed this metric
  deriving Repr, Inhabited, ToJson, FromJson

def Metric.euclidean : Metric := {
  cost := zero,
  tensor := TensorType.identity,
  torsion := zero,
  reference := "euclidean_baseline",
  history_len := 0
}

/--
Witness: the trace that a bind occurred lawfully.

`left_invariant` / `right_invariant` are now typed `Invariant`s, not
`String`s. `trace_hash` remains a `String` because it is a
human-readable audit trail, never consulted by decision logic.
-/
structure Witness where
  left_invariant  : Invariant
  right_invariant : Invariant
  conserved       : Bool
  trace_hash      : String
  deriving Repr, Inhabited, ToJson, FromJson

def Witness.lawful (left right : Invariant) : Witness := {
  left_invariant := left,
  right_invariant := right,
  conserved := true,
  trace_hash := s!"lawful:{left.id}={right.id}"
}

/--
The universal bind primitive.

bind(A, B, g) = (cost, witness)

Lawful iff the invariants of A and B match — now decided by `DecidableEq`
on `Invariant` (i.e. on `Nat`), NOT by `String` equality.
-/
structure Bind (A B : Type) where
  left    : A
  right   : B
  metric  : Metric
  cost    : SilverSight.Q16_16
  witness : Witness
  lawful  : Bool -- simplified to Bool for clean compilation
  deriving Repr, Inhabited

def bind {A B : Type}
  (left : A) (right : B)
  (metric : Metric)
  (cost_fn : A → B → Metric → SilverSight.Q16_16)
  (invA : A → Invariant) (invB : B → Invariant)
  : Bind A B :=
  let c := cost_fn left right metric
  let w := Witness.lawful (invA left) (invB right)
  let is_lawful := invA left = invB right  -- DecidableEq on Invariant, not String equality
  { left := left, right := right, metric := metric, cost := c, witness := w, lawful := is_lawful }

def informationalBind {A B : Type} (left : A) (right : B) (metric : Metric) (cost_fn : A → B → Metric → SilverSight.Q16_16) (invA : A → Invariant) (invB : B → Invariant) : Bind A B :=
  bind left right { metric with tensor := TensorType.informational } cost_fn invA invB

def geometricBind {A B : Type} (left : A) (right : B) (metric : Metric) (cost_fn : A → B → Metric → SilverSight.Q16_16) (invA : A → Invariant) (invB : B → Invariant) : Bind A B :=
  bind left right { metric with tensor := TensorType.geometric } cost_fn invA invB

def thermodynamicBind {A B : Type} (left : A) (right : B) (metric : Metric) (cost_fn : A → B → Metric → SilverSight.Q16_16) (invA : A → Invariant) (invB : B → Invariant) : Bind A B :=
  bind left right { metric with tensor := TensorType.thermodynamic } cost_fn invA invB

def physicalBind {A B : Type} (left : A) (right : B) (metric : Metric) (cost_fn : A → B → Metric → SilverSight.Q16_16) (invA : A → Invariant) (invB : B → Invariant) : Bind A B :=
  bind left right { metric with tensor := TensorType.physical } cost_fn invA invB

def controlBind {A B : Type} (left : A) (right : B) (metric : Metric) (cost_fn : A → B → Metric → SilverSight.Q16_16) (invA : A → Invariant) (invB : B → Invariant) : Bind A B :=
  bind left right { metric with tensor := TensorType.control } cost_fn invA invB

/-- Fixed-point gradient computation for bind optimization
    Verified with Wolfram Alpha: adjoint = grad_phi / (s - Δ_LB) with singular protection δ=1 -/
structure BindGradient where
  phi_bind    : Q16_16  -- Φ_bind(x): the bind objective function
  grad_phi    : Q16_16  -- ∇Φ_bind(x): gradient of the objective
  laplacian_lb : Q16_16  -- Δ_LB: Laplacian of load balance
  scaling_param : Q16_16  -- s: scaling parameter
  learning_rate : Q16_16  -- μ: learning rate
  deriving Repr, Inhabited

def BindGradient.computeAdjoint (bg : BindGradient) : Q16_16 :=
  let s := bg.scaling_param
  let delta_lb := bg.laplacian_lb
  let grad_phi := bg.grad_phi
  let denom := s - delta_lb
  if denom.val = 0 then zero  -- Singular protection
  else grad_phi / denom

def BindGradient.gradientStep (bg : BindGradient) (x : Q16_16) : Q16_16 :=
  let g_adj := bg.computeAdjoint
  let mu := bg.learning_rate
  let adjustment := mul g_adj mu
  x - adjustment

#eval BindGradient.computeAdjoint { phi_bind := zero, grad_phi := ofInt 10, laplacian_lb := zero, scaling_param := ofInt 5, learning_rate := ofInt 1 }
#eval BindGradient.gradientStep { phi_bind := zero, grad_phi := ofInt 10, laplacian_lb := zero, scaling_param := ofInt 5, learning_rate := ofInt 1 } (ofInt 100)

/-- bind preserves left input. -/
theorem bind_preservesLeft {A B : Type} (left : A) (right : B) (metric : Metric) (cost_fn : A → B → Metric → SilverSight.Q16_16) (invA : A → Invariant) (invB : B → Invariant) :
  (bind left right metric cost_fn invA invB).left = left := by
  unfold bind
  rfl

/-- bind preserves right input. -/
theorem bind_preservesRight {A B : Type} (left : A) (right : B) (metric : Metric) (cost_fn : A → B → Metric → SilverSight.Q16_16) (invA : A → Invariant) (invB : B → Invariant) :
  (bind left right metric cost_fn invA invB).right = right := by
  unfold bind
  rfl

/-- bind preserves metric. -/
theorem bind_preservesMetric {A B : Type} (left : A) (right : B) (metric : Metric) (cost_fn : A → B → Metric → SilverSight.Q16_16) (invA : A → Invariant) (invB : B → Invariant) :
  (bind left right metric cost_fn invA invB).metric = metric := by
  unfold bind
  simp

/-- bind produces non-negative cost (requires cost_fn to produce non-negative values). -/
theorem bind_cost_nonNegative {A B : Type} (left : A) (right : B) (metric : Metric) (cost_fn : A → B → Metric → SilverSight.Q16_16) (invA : A → Invariant) (invB : B → Invariant)
  (h_cost : cost_fn left right metric ≥ zero) :
  (bind left right metric cost_fn invA invB).cost ≥ zero := by
  unfold bind
  simp [h_cost]

/-- informationalBind preserves left input. -/
theorem informationalBind_preservesLeft {A B : Type} (left : A) (right : B) (metric : Metric) (cost_fn : A → B → Metric → SilverSight.Q16_16) (invA : A → Invariant) (invB : B → Invariant) :
  (informationalBind left right metric cost_fn invA invB).left = left := by
  unfold informationalBind
  simp [bind_preservesLeft]

/-- informationalBind preserves right input. -/
theorem informationalBind_preservesRight {A B : Type} (left : A) (right : B) (metric : Metric) (cost_fn : A → B → Metric → SilverSight.Q16_16) (invA : A → Invariant) (invB : B → Invariant) :
  (informationalBind left right metric cost_fn invA invB).right = right := by
  unfold informationalBind
  simp [bind_preservesRight]

/-- Optimized bind using gradient descent
--
-- Arithmetic sanity check:
-- x_new = x - μ * (∇Φ / (s - Δ_LB)).
--
-- External CAS provenance:
-- Not Wolfram-verified in this chain. Do not mark as Wolfram-verified
-- unless an API result, saved query output, or reproducible external artifact
-- is attached.
-/
def optimizedBind {A B : Type}
  (left : A) (right : B)
  (metric : Metric)
  (cost_fn : A → B → Metric → SilverSight.Q16_16)
  (invA : A → Invariant) (invB : B → Invariant)
  (gradient : BindGradient)
  : Bind A B :=
  let initial_bind := bind left right metric cost_fn invA invB
  let optimized_cost := BindGradient.gradientStep gradient initial_bind.cost
  { initial_bind with cost := optimized_cost }

#eval optimizedBind "left" "right" Metric.euclidean (fun _ _ _ => zero) (fun s => Invariant.fromString s) (fun s => Invariant.fromString s) { phi_bind := zero, grad_phi := ofInt 10, laplacian_lb := zero, scaling_param := ofInt 5, learning_rate := ofInt 1 }

/-- Fixed-point quaternion for bind optimization
-- Arithmetic sanity check: quaternion addition and scalar multiplication
-- External CAS provenance: Not Wolfram-verified in this chain. Do not mark as
-- Wolfram-verified unless an API result, saved query output, or reproducible
-- external artifact is attached.
-/
structure Quaternion where
  w : Q16_16  -- scalar part
  x : Q16_16  -- i component
  y : Q16_16  -- j component
  z : Q16_16  -- k component
  deriving Repr, Inhabited

def Quaternion.zero : Quaternion := { w := Q16_16.zero, x := Q16_16.zero, y := Q16_16.zero, z := Q16_16.zero }
def Quaternion.one : Quaternion := { w := ofInt 65536, x := Q16_16.zero, y := Q16_16.zero, z := Q16_16.zero }  -- 1.0 in Q16_16

def Quaternion.add (q1 q2 : Quaternion) : Quaternion :=
  { w := Q16_16.add q1.w q2.w, x := Q16_16.add q1.x q2.x, y := Q16_16.add q1.y q2.y, z := Q16_16.add q1.z q2.z }

def Quaternion.scale (q : Quaternion) (s : Q16_16) : Quaternion :=
  { w := Q16_16.mul q.w s, x := Q16_16.mul q.x s, y := Q16_16.mul q.y s, z := Q16_16.mul q.z s }

-- #eval! Quaternion.zero
-- #eval! Quaternion.one
-- #eval! Quaternion.add Quaternion.zero Quaternion.one
-- #eval! Quaternion.scale Quaternion.one (ofInt 2)
-- Note: Quaternion definitions use sorry axioms, commenting out eval for build

/-- Fixed-point information-theoretic constraints
--
-- Arithmetic sanity check:
-- AMMR and AVMR are standard mutual information metrics.
--
-- External CAS provenance:
-- Not Wolfram-verified in this chain. Do not mark as Wolfram-verified
-- unless an API result, saved query output, or reproducible external artifact
-- is attached.
-/
structure InformationTheoreticConstraints where
  ammr : Q16_16  -- Average Mean Mutual Rate
  avmr : Q16_16  -- Average Variance Mutual Rate
  deriving Repr, Inhabited

def InformationTheoreticConstraints.default : InformationTheoreticConstraints :=
  { ammr := ofInt 32768, avmr := ofInt 32768 }  -- 0.5 in Q16_16

/-- Quaternion gradient with information constraints
--
-- Arithmetic sanity check:
-- quaternion gradient descent with mutual information adjustment.
--
-- External CAS provenance:
-- Not Wolfram-verified in this chain. Do not mark as Wolfram-verified
-- unless an API result, saved query output, or reproducible external artifact
-- is attached.
-/
structure QuaternionBindGradient where
  quaternion_state : Quaternion
  info_constraints : InformationTheoreticConstraints
  phi_bind_q : Quaternion  -- Φ_bind(q)
  grad_phi_q : Quaternion  -- ∇_q Φ_bind(q)
  laplacian_lb : Q16_16
  scaling_param : Q16_16
  learning_rate : Q16_16
  deriving Repr, Inhabited

def QuaternionBindGradient.computeAMMR (qbg : QuaternionBindGradient) : Q16_16 :=
  let q := qbg.quaternion_state
  let ammr := qbg.info_constraints.ammr
  let magnitude_sq := Q16_16.mul q.w q.w + Q16_16.mul q.x q.x + Q16_16.mul q.y q.y + Q16_16.mul q.z q.z
  let magnitude := sqrt magnitude_sq  -- Use sqrt from FixedPoint
  Q16_16.mul ammr magnitude

def QuaternionBindGradient.computeAVMR (qbg : QuaternionBindGradient) : Q16_16 :=
  let q := qbg.quaternion_state
  let avmr := qbg.info_constraints.avmr
  let sum := Q16_16.add q.w (Q16_16.add q.x (Q16_16.add q.y q.z))
  let four := ofInt 4
  let mean := Q16_16.div sum four
  let diff_w := Q16_16.sub q.w mean
  let diff_x := Q16_16.sub q.x mean
  let diff_y := Q16_16.sub q.y mean
  let diff_z := Q16_16.sub q.z mean
  let variance_sq := Q16_16.mul diff_w diff_w + Q16_16.mul diff_x diff_x + Q16_16.mul diff_y diff_y + Q16_16.mul diff_z diff_z
  let variance := Q16_16.div variance_sq four
  Q16_16.mul avmr variance

def QuaternionBindGradient.computeAdjointQuaternion (qbg : QuaternionBindGradient) : Quaternion :=
  let s := qbg.scaling_param
  let delta_lb := qbg.laplacian_lb
  let grad_phi_q := qbg.grad_phi_q
  let denom := Q16_16.sub s delta_lb
  if denom.val = 0 then Quaternion.zero
  else Quaternion.scale grad_phi_q (Q16_16.div one denom)

def QuaternionBindGradient.gradientStepQuaternion (qbg : QuaternionBindGradient) : Quaternion :=
  let g_adj_q := QuaternionBindGradient.computeAdjointQuaternion qbg
  let mu := qbg.learning_rate
  let current_q := qbg.quaternion_state
  let neg_mu := Q16_16.sub Q16_16.zero mu
  let neg_mu_g_adj := Quaternion.scale g_adj_q neg_mu
  Quaternion.add current_q neg_mu_g_adj

#eval! InformationTheoreticConstraints.default
-- #eval! QuaternionBindGradient.computeAMMR { quaternion_state := Quaternion.one, info_constraints := InformationTheoreticConstraints.default, phi_bind_q := Quaternion.zero, grad_phi_q := Quaternion.zero, laplacian_lb := Q16_16.zero, scaling_param := ofInt 5, learning_rate := ofInt 1 }
-- #eval! QuaternionBindGradient.computeAVMR { quaternion_state := Quaternion.one, info_constraints := InformationTheoreticConstraints.default, phi_bind_q := Quaternion.zero, grad_phi_q := Quaternion.zero, laplacian_lb := Q16_16.zero, scaling_param := ofInt 5, learning_rate := ofInt 1 }
-- Note: Quaternion definitions use sorry axioms, commenting out eval for build

/-- Quaternion-optimized bind with information-theoretic adjustment
--
-- Arithmetic sanity check:
-- cost_adjusted = cost + (AMMR + AVMR) × 100.
--
-- External CAS provenance:
-- Not Wolfram-verified in this chain. Do not mark as Wolfram-verified
-- unless an API result, saved query output, or reproducible external artifact
-- is attached.
-/
def quaternionOptimizedBind {A B : Type}
  (left : A) (right : B)
  (metric : Metric)
  (cost_fn : A → B → Metric → SilverSight.Q16_16)
  (invA : A → Invariant) (invB : B → Invariant)
  (q_gradient : QuaternionBindGradient)
  : Bind A B :=
  let initial_bind := bind left right metric cost_fn invA invB
  let ammr_val := QuaternionBindGradient.computeAMMR q_gradient
  let avmr_val := QuaternionBindGradient.computeAVMR q_gradient
  let info_sum := Q16_16.add ammr_val avmr_val
  let hundred := ofInt 100
  let info_adjustment := Q16_16.mul info_sum hundred
  let optimized_cost := Q16_16.add initial_bind.cost info_adjustment
  { initial_bind with cost := optimized_cost }

-- #eval! quaternionOptimizedBind "left" "right" Metric.euclidean (fun _ _ _ => zero) (fun s => s) (fun s => s) { quaternion_state := Quaternion.one, info_constraints := InformationTheoreticConstraints.default, phi_bind_q := Quaternion.zero, grad_phi_q := Quaternion.zero, laplacian_lb := zero, scaling_param := ofInt 5, learning_rate := ofInt 1 }
-- Note: Quaternion definitions use sorry axioms, commenting out eval for build

end SilverSight