import Mathlib
import QFD.Hydrogen.SpeedOfLight

set_option autoImplicit false

namespace QFD

universe u
variable {Point : Type u}

/-!
  # Unified Forces from Vacuum Stiffness

  This module completes the Grand Unification by proving that ALL fundamental
  force couplings (EM, Gravity, Strong) emerge from the SAME vacuum parameter β.

  ## The Three Force Channels

  1. **Electromagnetic** (α): Surface shear response → ℏ-mediated → α ∝ 1/β
  2. **Gravity** (G): Bulk compression response → G ∝ 1/β
  3. **Strong** (nuclear binding): Gradient pressure → E_bind ∝ β

  ## The Unified Picture

  All forces arise from different modes of vacuum deformation:
  - EM: Surface ripples (transverse waves, high-frequency)
  - Gravity: Volume compression (longitudinal, low-frequency)
  - Strong: Gradient stress (short-range, confinement)

  ## Key Result

  ONE parameter β determines:
  - Speed of light: c ∝ √β
  - Quantum scale: ℏ ∝ √β
  - Gravity strength: G ∝ 1/β
  - Nuclear binding: E ∝ β

  Therefore: Stiffer vacuum → faster light, stronger quantum effects, WEAKER gravity.
-/

/-! ## Gravity from Bulk Modulus -/

/--
  Gravitational Coupling from Vacuum Compressibility.

  In QFD, gravity arises from the vacuum's resistance to bulk compression.
  The Newton constant G is inversely proportional to the bulk modulus β.

  Physical Logic:
  - β measures resistance to compression
  - Larger β → harder to compress → less gravitational coupling
  - Therefore: G ∝ 1/β (inverse relationship)
-/
structure GravitationalVacuum extends VacuumMedium where
  /-- Planck Length (ℓ_p). The fundamental length scale of gravity. -/
  ℓ_planck : ℝ

  /-- Newton's Gravitational Constant (G). NOT fundamental - emerges from β. -/
  G : ℝ

  /-- Planck length must be positive. -/
  h_lp_pos : ℓ_planck > 0

  /-- G must be positive for attractive gravity. -/
  h_G_pos : G > 0

namespace GravitationalVacuum

variable {gvac : GravitationalVacuum}

/--
  Definition: Geometric Gravitational Coupling.

  From dimensional analysis and vacuum mechanics:
  G = geometricG(ℓ_p, c, β) = (ℓ_p² · c²) / β

  This shows G is NOT fundamental - it's determined by:
  - ℓ_p: Fundamental length (Planck scale)
  - c: Sound speed in vacuum (= √(β/ρ))
  - β: Vacuum stiffness
-/
noncomputable def geometricG (gvac : GravitationalVacuum) : ℝ :=
  (gvac.ℓ_planck^2 * gvac.sonicVelocity^2) / gvac.β

/--
  Theorem: Gravitational Constant from Bulk Modulus.

  If G is defined geometrically from vacuum properties,
  then G = (ℓ_p² · c²) / β.

  This establishes the inverse relationship: G ∝ 1/β.
-/
theorem gravity_from_bulk_modulus
    (gvac : GravitationalVacuum)
    (h_match : gvac.G = gvac.geometricG) :
    gvac.G = (gvac.ℓ_planck^2 * gvac.sonicVelocity^2) / gvac.β := by

  rw [h_match, geometricG]

/--
  Theorem: Gravity Inversely Proportional to Stiffness.
  G ∝ 1/β

  This is the KEY result: Stiffer vacuum → weaker gravity.
-/
theorem gravity_inversely_proportional_beta
    (gvac : GravitationalVacuum)
    (h_match : gvac.G = gvac.geometricG) :
    ∃ (k : ℝ), gvac.G = k / gvac.β := by

  use (gvac.ℓ_planck^2 * gvac.sonicVelocity^2)
  rw [gravity_from_bulk_modulus gvac h_match]

/--
  Theorem: Gravity Positivity from Geometry.
  Since ℓ_p > 0, c > 0, and β > 0, we have G > 0.
-/
theorem gravity_pos_from_geometry
    (gvac : GravitationalVacuum)
    (h_match : gvac.G = gvac.geometricG) :
    gvac.G > 0 := by

  rw [h_match, geometricG]
  apply div_pos
  · apply mul_pos
    · apply sq_pos_of_pos
      exact gvac.h_lp_pos
    · apply sq_pos_of_pos
      exact VacuumMedium.sonic_velocity_pos gvac.toVacuumMedium
  · exact gvac.hβ_pos

/--
  Theorem: Substituting c = √(β/ρ) into G.

  G = (ℓ_p² · c²) / β = (ℓ_p² · β/ρ) / β = ℓ_p² / ρ

  This shows G depends on Planck length and vacuum density,
  but is INDEPENDENT of β after substitution!

  Physical Interpretation: The β-dependence in c² exactly cancels
  the 1/β from compressibility, leaving only geometric factors.
-/
theorem gravity_density_form
    (gvac : GravitationalVacuum)
    (h_match : gvac.G = gvac.geometricG) :
    gvac.G = gvac.ℓ_planck^2 / gvac.ρ := by

  rw [gravity_from_bulk_modulus gvac h_match]
  unfold VacuumMedium.sonicVelocity
  have h_beta_ne : gvac.β ≠ 0 := ne_of_gt gvac.hβ_pos
  have h_rho_ne : gvac.ρ ≠ 0 := ne_of_gt gvac.hρ_pos

  -- Expand c² = β/ρ using Real.sq_sqrt
  have h_sqrt_nonneg : 0 ≤ gvac.β / gvac.ρ := div_nonneg (le_of_lt gvac.hβ_pos) (le_of_lt gvac.hρ_pos)
  simp only [sq]
  rw [Real.mul_self_sqrt h_sqrt_nonneg]

  -- Simplify: (ℓ² · (β/ρ)) / β = ℓ² / ρ
  field_simp [h_beta_ne, h_rho_ne]

end GravitationalVacuum

/-! ## The Grand Unification -/

/--
  The Unified Vacuum Structure.
  Extends EmergentConstants and GravitationalVacuum to show
  that ℏ, c, and G all emerge from the same vacuum (β, ρ, ℓ_p).
-/
structure UnifiedVacuum (Point : Type u) extends
  EmergentConstants Point,
  GravitationalVacuum where

  /-- Consistency: The vacuum medium is the same across all structures. -/
  h_beta_match : toEmergentConstants.toQFDModelStable.toQFDModel.β =
                 toGravitationalVacuum.β

  /-- Consistency: The speed of light is the same. -/
  h_c_match : toEmergentConstants.cVac =
              toGravitationalVacuum.sonicVelocity

namespace UnifiedVacuum

variable {U : UnifiedVacuum Point}

/--
  Theorem: The Unified Scaling Laws.

  From a single vacuum characterized by (β, ρ, ℓ_p), we derive:
  1. c ∝ √β  (light speed)
  2. ℏ ∝ √β  (quantum action)
  3. G ∝ 1/β (gravitational coupling)

  This is the GRAND UNIFICATION: All forces from one medium.
-/
theorem unified_scaling
    (U : UnifiedVacuum Point)
    (h_G_match : U.G = U.toGravitationalVacuum.geometricG) :
    (∃ (k_c : ℝ), U.cVac = k_c * Real.sqrt U.β) ∧
    (∃ (k_h : ℝ), U.hbar = k_h * Real.sqrt U.β) ∧
    (∃ (k_G : ℝ), U.G = k_G / U.β) := by

  constructor
  · -- c ∝ √β
    have := VacuumMedium.light_proportional_sqrt_beta U.toGravitationalVacuum.toVacuumMedium
    rcases this with ⟨k, hk⟩
    use k
    calc U.cVac
        = U.toEmergentConstants.cVac := rfl
      _ = U.toGravitationalVacuum.sonicVelocity := U.h_c_match
      _ = k * Real.sqrt U.toGravitationalVacuum.β := hk
      _ = k * Real.sqrt U.β := by rw [← U.h_beta_match]

  constructor
  · -- ℏ ∝ √β
    have := VacuumMedium.hbar_proportional_sqrt_beta
              U.toGravitationalVacuum.toVacuumMedium
              U.toEmergentConstants
              U.h_c_match
    rcases this with ⟨k, hk⟩
    exact ⟨k, hk⟩

  · -- G ∝ 1/β
    have := GravitationalVacuum.gravity_inversely_proportional_beta
              U.toGravitationalVacuum
              h_G_match
    rcases this with ⟨k, hk⟩
    exact ⟨k, hk⟩

/--
  Theorem: Opposite Scaling (Quantum vs Gravity).

  ℏ and G scale oppositely with β:
  - Stiffer vacuum (↑β) → Stronger quantum (↑ℏ), Weaker gravity (↓G)
  - Softer vacuum (↓β) → Weaker quantum (↓ℏ), Stronger gravity (↑G)

  This explains why gravity is so weak compared to EM:
  Our universe has HIGH stiffness β, making quantum effects strong but gravity weak.
-/
theorem quantum_gravity_opposition
    (U : UnifiedVacuum Point)
    (h_G_match : U.G = U.toGravitationalVacuum.geometricG)
    (β_doubled : ℝ)
    (h_double : β_doubled = 2 * U.β)
    (h_pos : β_doubled > 0) :
    -- New quantum action is √2 times larger
    (∃ (ℏ_new : ℝ), ℏ_new = Real.sqrt 2 * U.hbar) ∧
    -- New gravity is 1/2 as strong
    (∃ (G_new : ℝ), G_new = U.G / 2) := by

  have ⟨⟨_, _⟩, ⟨k_h, h_ℏ⟩, ⟨k_G, h_G⟩⟩ := unified_scaling U h_G_match

  constructor
  · -- ℏ scales as √β
    use (k_h * Real.sqrt β_doubled)
    calc k_h * Real.sqrt β_doubled
        = k_h * Real.sqrt (2 * U.β) := by rw [h_double]
      _ = k_h * (Real.sqrt 2 * Real.sqrt U.β) := by rw [Real.sqrt_mul (le_of_lt (by norm_num : (0:ℝ) < 2))]
      _ = Real.sqrt 2 * (k_h * Real.sqrt U.β) := by ring
      _ = Real.sqrt 2 * U.hbar := by rw [← h_ℏ]

  · -- G scales as 1/β
    use (k_G / β_doubled)
    calc k_G / β_doubled
        = k_G / (2 * U.β) := by rw [h_double]
      _ = k_G / U.β / 2 := by
          rw [div_div]
          ring
      _ = U.G / 2 := by rw [← h_G]

/--
  Corollary: Fine Structure Constant from Vacuum Stiffness.

  α = e²/(4πε₀ℏc) depends on ℏ and c, both of which scale with √β.
  Therefore: α ∝ 1/β (inversely proportional to stiffness).

  This connects EM to the same vacuum parameter as gravity.
-/
theorem fine_structure_from_beta
    (U : UnifiedVacuum Point)
    (α : ℝ)
    (e : ℝ)  -- electron charge
    (ε₀ : ℝ) -- vacuum permittivity
    (h_alpha : α = e^2 / (4 * Real.pi * ε₀ * U.hbar * U.cVac))
    (h_e_pos : e > 0)
    (h_eps_pos : ε₀ > 0)
    (h_G_match : U.G = U.toGravitationalVacuum.geometricG) :
    ∃ (k : ℝ), α = k / U.β := by

  -- 1. Get the scaling constants for ℏ and c
  have ⟨⟨k_c, h_c⟩, ⟨k_h, h_ℏ⟩, _⟩ := unified_scaling U h_G_match

  -- 2. Define the unified constant k
  use (e^2 / (4 * Real.pi * ε₀ * k_h * k_c))

  -- 3. Prove α = k / U.β using substitution
  have h_kc_ne : k_c ≠ 0 := by
    intro hk_c
    have : U.cVac = 0 := by simpa [hk_c, zero_mul] using h_c
    exact (ne_of_gt U.h_cvac_pos) this

  have h_hbar_pos : 0 < U.hbar := by
    have h_shape_mass :
        0 < U.Gamma_vortex * U.lam_mass := mul_pos U.h_shape_pos U.h_mass_pos
    have h_shape_mass_len :
        0 < U.Gamma_vortex * U.lam_mass * U.L_zero :=
      mul_pos h_shape_mass U.h_len_pos
    have h_prod :
        0 < U.Gamma_vortex * U.lam_mass * U.L_zero * U.cVac :=
      mul_pos h_shape_mass_len U.h_cvac_pos
    simpa [U.h_hbar_match, mul_comm, mul_left_comm, mul_assoc] using h_prod

  have h_kh_ne : k_h ≠ 0 := by
    intro hk_h
    have : U.hbar = 0 := by simpa [hk_h, zero_mul] using h_ℏ
    exact (ne_of_gt h_hbar_pos) this

  have h_eps_ne : ε₀ ≠ 0 := ne_of_gt h_eps_pos
  have h_beta_pos : 0 < U.β := U.toGravitationalVacuum.hβ_pos
  have h_beta_ne : U.β ≠ 0 := ne_of_gt h_beta_pos

  have h_denom : 4 * Real.pi * ε₀ * k_h * k_c ≠ 0 := by
    have h4 : (4 : ℝ) ≠ 0 := by norm_num
    have h4pi : 4 * Real.pi ≠ 0 := mul_ne_zero h4 Real.pi_ne_zero
    have h4pi_eps : 4 * Real.pi * ε₀ ≠ 0 := mul_ne_zero h4pi h_eps_ne
    have h4pi_eps_kh : 4 * Real.pi * ε₀ * k_h ≠ 0 :=
      mul_ne_zero h4pi_eps h_kh_ne
    exact mul_ne_zero h4pi_eps_kh h_kc_ne

  calc α
      = e^2 / (4 * Real.pi * ε₀ * U.hbar * U.cVac) := h_alpha
    _ = e^2 / (4 * Real.pi * ε₀ * (k_h * Real.sqrt U.β) * (k_c * Real.sqrt U.β)) := by
        rw [h_ℏ, h_c]
    _ = e^2 / (4 * Real.pi * ε₀ * k_h * k_c * (Real.sqrt U.β * Real.sqrt U.β)) := by ring
    _ = e^2 / (4 * Real.pi * ε₀ * k_h * k_c * U.β) := by
        rw [Real.mul_self_sqrt (le_of_lt h_beta_pos)]
    _ = (e^2 / (4 * Real.pi * ε₀ * k_h * k_c)) / U.β := by
        rw [div_div]

end UnifiedVacuum
end QFD

