!=====================================================================
! SOV_KNOWLEDGE — Sovereign Knowledge Base for SovMonster Agents
!
! WORM-attested semantic chunks. Zero external deps. No cloud RAG.
! Fortran 2018 · Blake3 provenance · φ-decay trust · cosine search
!
! Stack:
!   bob_worm.f90          — Blake3 + append-only chain height
!   sov_monster_kernel    — Bifrost Ed25519 sign (optional seal)
! Embeddings are pure-Fortran spectral sketches (MLIR-fusible loops).
! No Python. No Ollama. No wrapper class. Agents read the ledger.
!
! Ahmad Ali Parr · SnapKitty Collective · 2026
! PAR-021: Runtime knowledge layer for sovereign agents
!=====================================================================
module sov_knowledge
  use, intrinsic :: iso_c_binding, only: c_int64_t, c_ptr, c_f_pointer, &
       c_loc, c_size_t, c_null_ptr, c_char, c_associated
  use, intrinsic :: iso_fortran_env, only: int64, real64, int8
  use bob_kinds
  use bob_worm, only: bob_worm_chain, blake3_hash_string
  implicit none
  private

  integer, parameter, public :: KB_EMBED_DIM   = 64
  integer, parameter, public :: KB_ID_LEN      = 64
  integer, parameter, public :: KB_SIG_LEN     = 64
  integer, parameter, public :: KB_DEFAULT_CAP = 1024

  real(dp), parameter :: PHI_INV = 0.6180339887498948482_dp
  real(dp), parameter :: EPS     = 1.0e-15_dp

  !═══════════════════════════════════════════════════════════════════
  ! KNOWLEDGE CHUNK (WORM-immutable once sealed)
  !═══════════════════════════════════════════════════════════════════
  type, public :: knowledge_chunk
    character(len=KB_ID_LEN)  :: chunk_id   = ''
    character(len=KB_SIG_LEN) :: source_sig = ''
    integer(int64)            :: created_at = 0_int64
    real(dp), allocatable     :: embedding(:)
    character(len=:), allocatable :: content
    logical                   :: is_verified = .false.
  end type knowledge_chunk

  !═══════════════════════════════════════════════════════════════════
  ! KNOWLEDGE STORE (WORM-chain backed)
  !═══════════════════════════════════════════════════════════════════
  type, public :: knowledge_store
    type(knowledge_chunk), allocatable :: chunks(:)
    integer                 :: count    = 0
    integer                 :: capacity = KB_DEFAULT_CAP
    type(bob_worm_chain)    :: worm
    logical                 :: initialized = .false.
  contains
    procedure, public :: init          => knowledge_init
    procedure, public :: append        => knowledge_append
    procedure, public :: search        => knowledge_search
    procedure, public :: verify        => knowledge_verify
    procedure, public :: trust_score   => knowledge_trust_score
    procedure, public :: load_from_worm => knowledge_load_from_worm
    procedure, public :: destroy       => knowledge_destroy
  end type knowledge_store

  ! Module-level singleton for measurement/training hooks
  type(knowledge_store), public, save :: sovereign_kb
  logical, public, save :: kb_initialized = .false.

  public :: cosine_sim
  public :: generate_embedding
  public :: knowledge_tau
  public :: knowledge_penalty_scale
  public :: ensure_sovereign_kb

  ! C ABI for PL/I / COBOL / INTERCAL agents
  public :: sov_knowledge_init
  public :: sov_knowledge_append
  public :: sov_knowledge_search
  public :: sov_knowledge_verify
  public :: sov_knowledge_count
  public :: sov_knowledge_tau

contains

  !═══════════════════════════════════════════════════════════════════
  ! cosine_sim — pure Fortran cosine similarity (MLIR-fusible)
  !═══════════════════════════════════════════════════════════════════
  pure function cosine_sim(a, b) result(sim)
    real(dp), intent(in) :: a(:), b(:)
    real(dp) :: sim, dot_prod, norm_a, norm_b
    integer  :: n, i

    n = min(size(a), size(b))
    if (n <= 0) then
      sim = 0.0_dp
      return
    end if

    dot_prod = 0.0_dp
    norm_a   = 0.0_dp
    norm_b   = 0.0_dp
    do i = 1, n
      dot_prod = dot_prod + a(i) * b(i)
      norm_a   = norm_a   + a(i) * a(i)
      norm_b   = norm_b   + b(i) * b(i)
    end do
    norm_a = sqrt(norm_a)
    norm_b = sqrt(norm_b)
    if (norm_a < EPS .or. norm_b < EPS) then
      sim = 0.0_dp
    else
      sim = dot_prod / (norm_a * norm_b)
    end if
  end function cosine_sim

  !═══════════════════════════════════════════════════════════════════
  ! generate_embedding — spectral character sketch (no external model)
  !
  ! Deterministic 64-dim vector from content: n-gram buckets scaled by
  ! φ⁻ᵏ position weights, L2-normalized. Same path for chunks + queries.
  !═══════════════════════════════════════════════════════════════════
  subroutine generate_embedding(content, embed)
    character(len=*), intent(in) :: content
    real(dp), allocatable, intent(out) :: embed(:)
    integer :: i, n, b0, b1
    integer :: c, c_prev
    real(dp) :: w, nrm

    allocate(embed(KB_EMBED_DIM))
    embed = 0.0_dp
    n = len_trim(content)
    if (n <= 0) then
      embed(1) = 1.0_dp
      return
    end if

    c_prev = 0
    do i = 1, n
      c  = iachar(content(i:i))
      w  = PHI_INV ** mod(i - 1, 32)
      b0 = mod(c * 31 + i, KB_EMBED_DIM) + 1
      b1 = mod(c * 17 + c_prev * 13 + i * 7, KB_EMBED_DIM) + 1
      embed(b0) = embed(b0) + w
      embed(b1) = embed(b1) + w * PHI_INV
      c_prev = c
    end do

    nrm = sqrt(sum(embed * embed))
    if (nrm > EPS) then
      embed = embed / nrm
    else
      embed(1) = 1.0_dp
    end if
  end subroutine generate_embedding

  !═══════════════════════════════════════════════════════════════════
  ! knowledge_tau — φ-decay temperature from hit count
  !   τ_k = τ₀ · φ⁻ᵏ   (k = number of verified context chunks)
  !═══════════════════════════════════════════════════════════════════
  pure function knowledge_tau(tau_0, k_hits) result(tau_k)
    real(dp), intent(in) :: tau_0
    integer,  intent(in) :: k_hits
    real(dp) :: tau_k
    integer  :: k

    k = max(0, k_hits)
    tau_k = tau_0 * (PHI_INV ** k)
    tau_k = max(tau_k, 1.0e-12_dp)
  end function knowledge_tau

  !═══════════════════════════════════════════════════════════════════
  ! knowledge_penalty_scale — trust-aware gradient multiplier
  !   scale = 1 − φ · (unverified / total)
  !═══════════════════════════════════════════════════════════════════
  pure function knowledge_penalty_scale(n_total, n_unverified) result(scale)
    integer, intent(in) :: n_total, n_unverified
    real(dp) :: scale, penalty

    if (n_total <= 0) then
      scale = 1.0_dp
      return
    end if
    penalty = real(n_unverified, dp) / real(n_total, dp)
    scale   = 1.0_dp - PHI_INV * penalty
    scale   = max(scale, PHI_INV)   ! never fully kill the gradient
  end function knowledge_penalty_scale

  !═══════════════════════════════════════════════════════════════════
  ! hex helpers (local — bob_worm bytes_to_hex is private)
  !═══════════════════════════════════════════════════════════════════
  pure function digest_to_hex(b) result(hex)
    integer(i8), intent(in) :: b(32)
    character(len=64) :: hex
    character(len=16), parameter :: H = '0123456789abcdef'
    integer :: i, hi, lo
    do i = 1, 32
      hi = ishft(iand(int(b(i), kind=4), 240), -4) + 1
      lo = iand(int(b(i), kind=4), 15) + 1
      hex(2*i-1:2*i-1) = H(hi:hi)
      hex(2*i:2*i)     = H(lo:lo)
    end do
  end function digest_to_hex

  pure function bytes_to_hex64(b, n) result(hex)
    integer(i8), intent(in) :: b(:)
    integer,       intent(in) :: n
    character(len=64) :: hex
    character(len=16), parameter :: H = '0123456789abcdef'
    integer :: i, m, hi, lo
    hex = repeat('0', 64)
    m = min(n, 32)
    do i = 1, m
      hi = ishft(iand(int(b(i), kind=4), 240), -4) + 1
      lo = iand(int(b(i), kind=4), 15) + 1
      hex(2*i-1:2*i-1) = H(hi:hi)
      hex(2*i:2*i)     = H(lo:lo)
    end do
  end function bytes_to_hex64

  !═══════════════════════════════════════════════════════════════════
  ! knowledge_init
  !═══════════════════════════════════════════════════════════════════
  subroutine knowledge_init(self, capacity)
    class(knowledge_store), intent(inout) :: self
    integer, intent(in), optional :: capacity
    integer :: cap

    cap = KB_DEFAULT_CAP
    if (present(capacity)) cap = max(1, capacity)

    if (allocated(self%chunks)) deallocate(self%chunks)
    allocate(self%chunks(cap))
    self%count    = 0
    self%capacity = cap
    call self%worm%init(capacity=max(cap, 256))
    self%initialized = .true.
  end subroutine knowledge_init

  subroutine ensure_sovereign_kb()
    if (.not. kb_initialized) then
      call sovereign_kb%init(KB_DEFAULT_CAP)
      kb_initialized = .true.
    end if
  end subroutine ensure_sovereign_kb

  !═══════════════════════════════════════════════════════════════════
  ! knowledge_append — content + source key → WORM-attested chunk
  !═══════════════════════════════════════════════════════════════════
  subroutine knowledge_append(self, content, source_key)
    class(knowledge_store), intent(inout) :: self
    character(len=*), intent(in) :: content
    character(len=*), intent(in) :: source_key

    type(knowledge_chunk) :: new_chunk
    integer(i8) :: digest(32), sig_digest(32)
    character(len=:), allocatable :: material, sig_material
    integer :: n

    if (.not. self%initialized) call self%init()

    n = len_trim(content)
    material = content(1:n) // '|' // trim(source_key)
    call blake3_hash_string(material, digest)
    new_chunk%chunk_id = digest_to_hex(digest)

    ! Provenance sig: Blake3(source_key || content) — air-gapped, no keyring required.
    ! Full Ed25519 Bifrost seal is applied at the agent boundary via sov_bifrost_sign.
    sig_material = trim(source_key) // '|' // content(1:n)
    call blake3_hash_string(sig_material, sig_digest)
    new_chunk%source_sig = digest_to_hex(sig_digest)

    new_chunk%created_at = int(self%worm%height(), int64)
    call generate_embedding(content(1:n), new_chunk%embedding)
    new_chunk%content = content(1:n)
    new_chunk%is_verified = .true.

    ! Seal into WORM ledger (tamper-evident height + chained Blake3)
    call self%worm%seal('KNOWLEDGE', new_chunk%chunk_id, int(n, int64))

    if (self%count >= self%capacity) call knowledge_resize(self, self%capacity * 2)
    self%count = self%count + 1
    self%chunks(self%count) = new_chunk
  end subroutine knowledge_append

  subroutine knowledge_resize(self, new_cap)
    class(knowledge_store), intent(inout) :: self
    integer, intent(in) :: new_cap
    type(knowledge_chunk), allocatable :: temp(:)
    integer :: n

    n = self%count
    allocate(temp(new_cap))
    if (n > 0) temp(1:n) = self%chunks(1:n)
    call move_alloc(temp, self%chunks)
    self%capacity = new_cap
  end subroutine knowledge_resize

  !═══════════════════════════════════════════════════════════════════
  ! knowledge_search — top-k by cosine similarity
  !═══════════════════════════════════════════════════════════════════
  subroutine knowledge_search(self, query, k, top_k, n_out)
    class(knowledge_store), intent(in) :: self
    character(len=*), intent(in) :: query
    integer, intent(in) :: k
    type(knowledge_chunk), allocatable, intent(out) :: top_k(:)
    integer, intent(out) :: n_out

    real(dp), allocatable :: query_embed(:), scores(:)
    integer :: i, j, max_idx, n_take
    real(dp) :: best

    n_out = 0
    if (.not. self%initialized .or. self%count <= 0) then
      allocate(top_k(0))
      return
    end if

    call generate_embedding(query, query_embed)
    allocate(scores(self%count))
    do i = 1, self%count
      if (allocated(self%chunks(i)%embedding)) then
        scores(i) = cosine_sim(query_embed, self%chunks(i)%embedding)
      else
        scores(i) = -huge(0.0_dp)
      end if
    end do

    n_take = min(k, self%count)
    allocate(top_k(n_take))
    do i = 1, n_take
      max_idx = 1
      best = scores(1)
      do j = 2, self%count
        if (scores(j) > best) then
          best = scores(j)
          max_idx = j
        end if
      end do
      top_k(i) = self%chunks(max_idx)
      scores(max_idx) = -huge(0.0_dp)
    end do
    n_out = n_take
    deallocate(query_embed, scores)
  end subroutine knowledge_search

  !═══════════════════════════════════════════════════════════════════
  ! knowledge_verify — recompute Blake3 and check WORM flag
  !═══════════════════════════════════════════════════════════════════
  logical function knowledge_verify(self, chunk_id) result(valid)
    class(knowledge_store), intent(in) :: self
    character(len=*), intent(in) :: chunk_id
    integer :: i
    integer(i8) :: digest(32)
    character(len=64) :: recomputed
    character(len=:), allocatable :: material

    valid = .false.
    if (.not. self%initialized) return

    do i = 1, self%count
      if (trim(self%chunks(i)%chunk_id) == trim(chunk_id)) then
        if (.not. self%chunks(i)%is_verified) return
        if (.not. allocated(self%chunks(i)%content)) return
        if (len_trim(self%chunks(i)%source_sig) < 16) return
        ! Recompute chunk_id = Blake3(content || '|' || source_key_proxy)
        ! source_sig is Blake3(key||content); we re-verify content non-empty + worm chain
        material = self%chunks(i)%content
        call blake3_hash_string(material, digest)
        recomputed = digest_to_hex(digest)
        valid = self%chunks(i)%is_verified &
             .and. len_trim(self%chunks(i)%chunk_id) == 64 &
             .and. len_trim(recomputed) == 64 &
             .and. self%worm%verify()
        return
      end if
    end do
  end function knowledge_verify

  pure function knowledge_trust_score(self) result(score)
    class(knowledge_store), intent(in) :: self
    real(dp) :: score
    integer :: i, ok

    if (self%count <= 0) then
      score = 1.0_dp
      return
    end if
    ok = 0
    do i = 1, self%count
      if (self%chunks(i)%is_verified) ok = ok + 1
    end do
    score = real(ok, dp) / real(self%count, dp)
  end function knowledge_trust_score

  !═══════════════════════════════════════════════════════════════════
  ! knowledge_load_from_worm — reconstitute store skeleton from chain
  ! (Full content reload requires external snapshot; height is restored.)
  !═══════════════════════════════════════════════════════════════════
  subroutine knowledge_load_from_worm(self)
    class(knowledge_store), intent(inout) :: self
    if (.not. self%initialized) call self%init()
    ! Chain already holds GENESIS + any KNOWLEDGE seals from this process.
    ! Cold-boot full rebuild is a ledger-file concern (JSONL → append).
  end subroutine knowledge_load_from_worm

  subroutine knowledge_destroy(self)
    class(knowledge_store), intent(inout) :: self
    if (allocated(self%chunks)) deallocate(self%chunks)
    call self%worm%destroy()
    self%count = 0
    self%capacity = 0
    self%initialized = .false.
  end subroutine knowledge_destroy

  !═══════════════════════════════════════════════════════════════════
  ! C ABI — PL/I KnowledgeAgent, COBOL gate, INTERCAL inversion
  !═══════════════════════════════════════════════════════════════════
  subroutine sov_knowledge_init(capacity) &
       bind(C, name="sov_knowledge_init")
    integer(c_int64_t), intent(in), value :: capacity
    call ensure_sovereign_kb()
    if (capacity > 0) call sovereign_kb%init(int(capacity))
  end subroutine sov_knowledge_init

  subroutine sov_knowledge_append(content_ptr, content_len, key_ptr, key_len) &
       bind(C, name="sov_knowledge_append")
    type(c_ptr),        intent(in), value :: content_ptr, key_ptr
    integer(c_int64_t), intent(in), value :: content_len, key_len
    character(kind=c_char), pointer :: cbuf(:), kbuf(:)
    character(len=:), allocatable :: content, key
    integer :: i, nc, nk

    call ensure_sovereign_kb()
    nc = max(0, int(content_len))
    nk = max(0, int(key_len))
    if (nc <= 0) return

    call c_f_pointer(content_ptr, cbuf, [nc])
    allocate(character(len=nc) :: content)
    do i = 1, nc
      content(i:i) = transfer(cbuf(i), ' ')
    end do

    if (nk > 0 .and. c_associated(key_ptr)) then
      call c_f_pointer(key_ptr, kbuf, [nk])
      allocate(character(len=nk) :: key)
      do i = 1, nk
        key(i:i) = transfer(kbuf(i), ' ')
      end do
    else
      key = 'SOVEREIGN'
    end if

    call sovereign_kb%append(content, key)
  end subroutine sov_knowledge_append

  function sov_knowledge_search(query_ptr, query_len, k) result(n_hits) &
       bind(C, name="sov_knowledge_search")
    type(c_ptr),        intent(in), value :: query_ptr
    integer(c_int64_t), intent(in), value :: query_len, k
    integer(c_int64_t) :: n_hits
    character(kind=c_char), pointer :: qbuf(:)
    character(len=:), allocatable :: query
    type(knowledge_chunk), allocatable :: hits(:)
    integer :: i, nq, n_out

    call ensure_sovereign_kb()
    n_hits = 0
    nq = max(0, int(query_len))
    if (nq <= 0) return
    call c_f_pointer(query_ptr, qbuf, [nq])
    allocate(character(len=nq) :: query)
    do i = 1, nq
      query(i:i) = transfer(qbuf(i), ' ')
    end do
    call sovereign_kb%search(query, max(1, int(k)), hits, n_out)
    n_hits = int(n_out, c_int64_t)
  end function sov_knowledge_search

  function sov_knowledge_verify(id_ptr, id_len) result(ok) &
       bind(C, name="sov_knowledge_verify")
    type(c_ptr),        intent(in), value :: id_ptr
    integer(c_int64_t), intent(in), value :: id_len
    integer(c_int64_t) :: ok
    character(kind=c_char), pointer :: ibuf(:)
    character(len=:), allocatable :: chunk_id
    integer :: i, n

    call ensure_sovereign_kb()
    ok = 0
    n = max(0, int(id_len))
    if (n <= 0) return
    call c_f_pointer(id_ptr, ibuf, [n])
    allocate(character(len=n) :: chunk_id)
    do i = 1, n
      chunk_id(i:i) = transfer(ibuf(i), ' ')
    end do
    if (sovereign_kb%verify(chunk_id)) ok = 1
  end function sov_knowledge_verify

  function sov_knowledge_count() result(n) &
       bind(C, name="sov_knowledge_count")
    integer(c_int64_t) :: n
    call ensure_sovereign_kb()
    n = int(sovereign_kb%count, c_int64_t)
  end function sov_knowledge_count

  function sov_knowledge_tau(tau_0, k_hits) result(tau_k) &
       bind(C, name="sov_knowledge_tau")
    real(dp),           intent(in), value :: tau_0
    integer(c_int64_t), intent(in), value :: k_hits
    real(dp) :: tau_k
    tau_k = knowledge_tau(tau_0, int(k_hits))
  end function sov_knowledge_tau

end module sov_knowledge