package go_sectorbuilder

import (
	"unsafe"

	"github.com/filecoin-project/go-sectorbuilder/sealed_sector_health"

	"github.com/pkg/errors"
)

// #cgo LDFLAGS: ${SRCDIR}/libsector_builder_ffi.a
// #cgo pkg-config: ${SRCDIR}/sector_builder_ffi.pc
// #include "./sector_builder_ffi.h"
import "C"

// SingleProofPartitionProofLen denotes the number of bytes in a proof generated
// with a single partition. The number of bytes in a proof increases linearly
// with the number of partitions used when creating that proof.
const SingleProofPartitionProofLen = 192

func cPublicPieceInfo(src []PublicPieceInfo) (*C.sector_builder_ffi_FFIPublicPieceInfo, C.size_t) {
	srcCSizeT := C.size_t(len(src))

	// allocate array in C heap
	cPublicPieceInfos := C.malloc(srcCSizeT * C.sizeof_sector_builder_ffi_FFIPublicPieceInfo)

	// create a Go slice backed by the C-array
	xs := (*[1 << 30]C.sector_builder_ffi_FFIPublicPieceInfo)(cPublicPieceInfos)
	for i, v := range src {
		xs[i] = C.sector_builder_ffi_FFIPublicPieceInfo{
			num_bytes: C.uint64_t(v.Size),
			comm_p:    *(*[32]C.uint8_t)(unsafe.Pointer(&v.CommP)),
		}
	}

	return (*C.sector_builder_ffi_FFIPublicPieceInfo)(cPublicPieceInfos), srcCSizeT
}

func cPieceMetadata(src []PieceMetadata) (*C.sector_builder_ffi_FFIPieceMetadata, C.size_t) {
	srcCSizeT := C.size_t(len(src))

	// allocate array in C heap
	cPieceMetadata := C.malloc(srcCSizeT * C.sizeof_sector_builder_ffi_FFIPieceMetadata)

	// create a Go slice backed by the C-array
	xs := (*[1 << 30]C.sector_builder_ffi_FFIPieceMetadata)(cPieceMetadata)
	for i, v := range src {
		xs[i] = C.sector_builder_ffi_FFIPieceMetadata{
			piece_key: C.CString(v.Key),
			num_bytes: C.uint64_t(v.Size),
			comm_p:    *(*[32]C.uint8_t)(unsafe.Pointer(&v.CommP)),
		}
	}

	return (*C.sector_builder_ffi_FFIPieceMetadata)(cPieceMetadata), srcCSizeT
}

func cUint64s(src []uint64) (*C.uint64_t, C.size_t) {
	srcCSizeT := C.size_t(len(src))

	// allocate array in C heap
	cUint64s := C.malloc(srcCSizeT * C.sizeof_uint64_t)

	// create a Go slice backed by the C-array
	pp := (*[1 << 30]C.uint64_t)(cUint64s)
	for i, v := range src {
		pp[i] = C.uint64_t(v)
	}

	return (*C.uint64_t)(cUint64s), srcCSizeT
}

func cSectorClass(sectorSize uint64, poRepProofPartitions uint8) C.sector_builder_ffi_FFISectorClass {
	return C.sector_builder_ffi_FFISectorClass{
		sector_size:            C.uint64_t(sectorSize),
		porep_proof_partitions: C.uint8_t(poRepProofPartitions),
	}
}

func cSealPreCommitOutput(src RawSealPreCommitOutput) C.sector_builder_ffi_FFISealPreCommitOutput {
	return C.sector_builder_ffi_FFISealPreCommitOutput{
		comm_d:            *(*[32]C.uint8_t)(unsafe.Pointer(&src.CommD)),
		comm_r:            *(*[32]C.uint8_t)(unsafe.Pointer(&src.CommR)),
		p_aux_comm_c:      *(*[32]C.uint8_t)(unsafe.Pointer(&src.CommC)),
		p_aux_comm_r_last: *(*[32]C.uint8_t)(unsafe.Pointer(&src.CommRLast)),
	}
}

func cCandidates(src []Candidate) (*C.sector_builder_ffi_FFICandidate, C.size_t) {
	srcCSizeT := C.size_t(len(src))

	// allocate array in C heap
	cCandidates := C.malloc(srcCSizeT * C.sizeof_sector_builder_ffi_FFICandidate)

	// create a Go slice backed by the C-array
	pp := (*[1 << 30]C.sector_builder_ffi_FFICandidate)(cCandidates)
	for i, v := range src {
		pp[i] = C.sector_builder_ffi_FFICandidate{
			sector_id:              C.uint64_t(v.SectorID),
			partial_ticket:         *(*[32]C.uint8_t)(unsafe.Pointer(&v.PartialTicket)),
			ticket:                 *(*[32]C.uint8_t)(unsafe.Pointer(&v.Ticket)),
			sector_challenge_index: C.uint64_t(v.SectorChallengeIndex),
		}
	}

	return (*C.sector_builder_ffi_FFICandidate)(cCandidates), srcCSizeT
}

func cPrivateReplicaInfos(src []PrivateSectorInfo) (*C.sector_builder_ffi_FFIPrivateReplicaInfo, C.size_t) {
	srcCSizeT := C.size_t(len(src))

	cPrivateReplicas := C.malloc(srcCSizeT * C.sizeof_sector_builder_ffi_FFIPrivateReplicaInfo)

	pp := (*[1 << 30]C.sector_builder_ffi_FFIPrivateReplicaInfo)(cPrivateReplicas)
	for i, v := range src {
		pp[i] = C.sector_builder_ffi_FFIPrivateReplicaInfo{
			cache_dir_path: C.CString(v.CacheDirPath),
			comm_r:         *(*[32]C.uint8_t)(unsafe.Pointer(&v.CommR)),
			replica_path:   C.CString(v.SealedSectorPath),
			sector_id:      C.uint64_t(v.SectorID),
		}
	}

	return (*C.sector_builder_ffi_FFIPrivateReplicaInfo)(cPrivateReplicas), srcCSizeT
}

func goBytes(src *C.uint8_t, size C.size_t) []byte {
	return C.GoBytes(unsafe.Pointer(src), C.int(size))
}

func goSealTicket(src C.sector_builder_ffi_FFISealTicket) SealTicket {
	return SealTicket{
		TicketBytes: goCommitment(&src.ticket_bytes[0]),
		BlockHeight: uint64(src.block_height),
	}
}

func goCandidates(src *C.sector_builder_ffi_FFICandidate, size C.size_t) ([]Candidate, error) {
	candidates := make([]Candidate, size)
	if src == nil || size == 0 {
		return candidates, nil
	}

	ptrs := (*[1 << 30]C.sector_builder_ffi_FFICandidate)(unsafe.Pointer(src))[:size:size]
	for i := 0; i < int(size); i++ {
		candidates[i] = goCandidate(ptrs[i])
	}

	return candidates, nil
}

func goCandidate(src C.sector_builder_ffi_FFICandidate) Candidate {
	return Candidate{
		SectorID:             uint64(src.sector_id),
		PartialTicket:        goCommitment(&src.partial_ticket[0]),
		Ticket:               goCommitment(&src.ticket[0]),
		SectorChallengeIndex: uint64(src.sector_challenge_index),
	}
}

func goRawSealPreCommitOutput(src C.sector_builder_ffi_FFISealPreCommitOutput) RawSealPreCommitOutput {
	return RawSealPreCommitOutput{
		CommD:     goCommitment(&src.comm_d[0]),
		CommR:     goCommitment(&src.comm_r[0]),
		CommRLast: goCommitment(&src.p_aux_comm_r_last[0]),
		CommC:     goCommitment(&src.p_aux_comm_c[0]),
	}
}

func goCommitment(src *C.uint8_t) [32]byte {
	slice := C.GoBytes(unsafe.Pointer(src), 32)
	var array [CommitmentBytesLen]byte
	copy(array[:], slice)

	return array
}

func goSectorBuilderSealCommitOutput(src *C.sector_builder_ffi_SectorBuilderSealCommitResponse) (SealCommitOutput, error) {
	commDSlice := goBytes(&src.comm_d[0], CommitmentBytesLen)
	var commD [CommitmentBytesLen]byte
	copy(commD[:], commDSlice)

	commRSlice := goBytes(&src.comm_r[0], CommitmentBytesLen)
	var commR [CommitmentBytesLen]byte
	copy(commR[:], commRSlice)

	proof := goBytes(src.proofs_ptr, src.proofs_len)

	pieces, err := goPieceMetadata(src.pieces_ptr, src.pieces_len)
	if err != nil {
		return SealCommitOutput{}, errors.Wrap(err, "failed to marshal piece metadata")
	}

	return SealCommitOutput{
		SectorID: uint64(src.sector_id),
		CommD:    commD,
		CommR:    commR,
		Proof:    proof,
		Pieces:   pieces,
		Ticket:   goSealTicket(src.seal_ticket),
		Seed:     goSealSeed(src.seal_seed),
	}, nil
}

func goResumeSealCommitOutput(src *C.sector_builder_ffi_ResumeSealCommitResponse) (SealCommitOutput, error) {
	commDSlice := goBytes(&src.comm_d[0], CommitmentBytesLen)
	var commD [CommitmentBytesLen]byte
	copy(commD[:], commDSlice)

	commRSlice := goBytes(&src.comm_r[0], CommitmentBytesLen)
	var commR [CommitmentBytesLen]byte
	copy(commR[:], commRSlice)

	proof := goBytes(src.proofs_ptr, src.proofs_len)

	pieces, err := goPieceMetadata(src.pieces_ptr, src.pieces_len)
	if err != nil {
		return SealCommitOutput{}, errors.Wrap(err, "failed to marshal piece metadata")
	}

	return SealCommitOutput{
		SectorID: uint64(src.sector_id),
		CommD:    commD,
		CommR:    commR,
		Proof:    proof,
		Pieces:   pieces,
		Ticket:   goSealTicket(src.seal_ticket),
		Seed:     goSealSeed(src.seal_seed),
	}, nil
}

func goSectorBuilderSealPreCommitOutput(src *C.sector_builder_ffi_SectorBuilderSealPreCommitResponse) (SealPreCommitOutput, error) {
	commDSlice := goBytes(&src.comm_d[0], CommitmentBytesLen)
	var commD [CommitmentBytesLen]byte
	copy(commD[:], commDSlice)

	commRSlice := goBytes(&src.comm_r[0], CommitmentBytesLen)
	var commR [CommitmentBytesLen]byte
	copy(commR[:], commRSlice)

	pieces, err := goPieceMetadata(src.pieces_ptr, src.pieces_len)
	if err != nil {
		return SealPreCommitOutput{}, errors.Wrap(err, "failed to marshal piece metadata")
	}

	return SealPreCommitOutput{
		SectorID: uint64(src.sector_id),
		CommD:    commD,
		CommR:    commR,
		Pieces:   pieces,
		Ticket:   goSealTicket(src.seal_ticket),
	}, nil
}

func goResumeSealPreCommitOutput(src *C.sector_builder_ffi_ResumeSealPreCommitResponse) (SealPreCommitOutput, error) {
	commDSlice := goBytes(&src.comm_d[0], CommitmentBytesLen)
	var commD [CommitmentBytesLen]byte
	copy(commD[:], commDSlice)

	commRSlice := goBytes(&src.comm_r[0], CommitmentBytesLen)
	var commR [CommitmentBytesLen]byte
	copy(commR[:], commRSlice)

	pieces, err := goPieceMetadata(src.pieces_ptr, src.pieces_len)
	if err != nil {
		return SealPreCommitOutput{}, errors.Wrap(err, "failed to marshal piece metadata")
	}

	return SealPreCommitOutput{
		SectorID: uint64(src.sector_id),
		CommD:    commD,
		CommR:    commR,
		Pieces:   pieces,
		Ticket:   goSealTicket(src.seal_ticket),
	}, nil
}

func goSealSeed(src C.sector_builder_ffi_FFISealTicket) SealSeed {
	seedBytesSlice := C.GoBytes(unsafe.Pointer(&src.ticket_bytes[0]), 32)
	var seedBytes [CommitmentBytesLen]byte
	copy(seedBytes[:], seedBytesSlice)

	return SealSeed{
		TicketBytes: seedBytes,
		BlockHeight: uint64(src.block_height),
	}
}

func goStagedSectorMetadata(src *C.sector_builder_ffi_FFIStagedSectorMetadata, size C.size_t) ([]StagedSectorMetadata, error) {
	sectors := make([]StagedSectorMetadata, size)
	if src == nil || size == 0 {
		return sectors, nil
	}

	sectorPtrs := (*[1 << 30]C.sector_builder_ffi_FFIStagedSectorMetadata)(unsafe.Pointer(src))[:size:size]
	for i := 0; i < int(size); i++ {
		sectors[i] = StagedSectorMetadata{
			SectorID: uint64(sectorPtrs[i].sector_id),
		}
	}

	return sectors, nil
}

func goSealedSectorMetadata(src *C.sector_builder_ffi_FFISealedSectorMetadata, size C.size_t) ([]SealedSectorMetadata, error) {
	sectors := make([]SealedSectorMetadata, size)
	if src == nil || size == 0 {
		return sectors, nil
	}

	ptrs := (*[1 << 30]C.sector_builder_ffi_FFISealedSectorMetadata)(unsafe.Pointer(src))[:size:size]
	for i := 0; i < int(size); i++ {
		commDSlice := goBytes(&ptrs[i].comm_d[0], CommitmentBytesLen)
		var commD [CommitmentBytesLen]byte
		copy(commD[:], commDSlice)

		commRSlice := goBytes(&ptrs[i].comm_r[0], CommitmentBytesLen)
		var commR [CommitmentBytesLen]byte
		copy(commR[:], commRSlice)

		proof := goBytes(ptrs[i].proofs_ptr, ptrs[i].proofs_len)

		pieces, err := goPieceMetadata(ptrs[i].pieces_ptr, ptrs[i].pieces_len)
		if err != nil {
			return []SealedSectorMetadata{}, errors.Wrap(err, "failed to marshal piece metadata")
		}

		health, err := goSealedSectorHealth(ptrs[i].health)
		if err != nil {
			return []SealedSectorMetadata{}, errors.Wrap(err, "failed to marshal sealed sector health")
		}

		sectors[i] = SealedSectorMetadata{
			SectorID: uint64(ptrs[i].sector_id),
			CommD:    commD,
			CommR:    commR,
			Proof:    proof,
			Pieces:   pieces,
			Health:   health,
			Ticket:   goSealTicket(ptrs[i].seal_ticket),
			Seed:     goSealSeed(ptrs[i].seal_seed),
		}
	}

	return sectors, nil
}

func goPieceMetadata(src *C.sector_builder_ffi_FFIPieceMetadata, size C.size_t) ([]PieceMetadata, error) {
	ps := make([]PieceMetadata, size)
	if src == nil || size == 0 {
		return ps, nil
	}

	ptrs := (*[1 << 30]C.sector_builder_ffi_FFIPieceMetadata)(unsafe.Pointer(src))[:size:size]
	for i := 0; i < int(size); i++ {
		commPSlice := goBytes(&ptrs[i].comm_p[0], CommitmentBytesLen)
		var commP [CommitmentBytesLen]byte
		copy(commP[:], commPSlice)

		ps[i] = PieceMetadata{
			Key:   C.GoString(ptrs[i].piece_key),
			Size:  uint64(ptrs[i].num_bytes),
			CommP: commP,
		}
	}

	return ps, nil
}

func goSealedSectorHealth(health C.sector_builder_ffi_FFISealedSectorHealth) (sealed_sector_health.Health, error) {
	switch health {
	case C.Unknown:
		return sealed_sector_health.Unknown, nil
	case C.Ok:
		return sealed_sector_health.Ok, nil
	case C.ErrorInvalidChecksum:
		return sealed_sector_health.InvalidChecksum, nil
	case C.ErrorInvalidLength:
		return sealed_sector_health.InvalidLength, nil
	case C.ErrorMissing:
		return sealed_sector_health.Missing, nil
	default:
		return sealed_sector_health.Unknown, errors.Errorf("unhandled sealed sector health: %v", health)
	}
}