import Base
import ./sol.bend as S
import ./types.bend as Ty

# SPL Token account words (165-byte layout, little-endian u32 view):
#   0..7   mint
#   8..15  owner
#   16..17 amount (full SPL u64)
# Mint decimals live at byte 44 (low byte of word 11).
#
# TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA

# SPL Token program id, Tokenkeg...VQ5DA.
def token_id() -> Ty.Pubkey:
  Ty.Pk{
    3791052038,
    2476828119,
    1189202905,
    2893671374,
    3984962588,
    2436324191,
    2247461946,
    2835414910,
  }

# 42 words (168 bytes) covers the 165-byte token account.
def TOKEN_WORDS() -> Nat:
  42n

def token_mint(data: List<&2, U32>) -> Ty.Pubkey:
  S.get_pubkey(data, 0n)

def token_owner(data: List<&2, U32>) -> Ty.Pubkey:
  S.get_pubkey(data, 8n)

def token_amount(data: List<&2, U32>) -> Ty.u64:
  S.get_u64(data, 16n)

def token_set_amount(data: List<&2, U32>, amt: Ty.u64) -> List<&2, U32>:
  S.set_u64(data, 16n, amt)

# Low byte of mint word 11 (byte 44).
def mint_decimals(data: List<&2, U32>) -> U32:
  U32.and(S.get_u32(data, 11n), 255)

# Account owner is the Token program.
def acc_is_token(+a: Ty.Account) -> Bool:
  Ty.Pubkey.eq(S.owner(a), token_id())

# Both token accounts name the same mint.
def token_same_mint(+a: List<&2, U32>, +b: List<&2, U32>) -> Bool:
  Ty.Pubkey.eq(token_mint(a), token_mint(b))

# Token-account owner word equals owner.
def token_owned(+data: List<&2, U32>, +owner: Ty.Pubkey) -> Bool:
  Ty.Pubkey.eq(token_owner(data), owner)