// Copyright (c) 2026 Charles KWON OhJun (charleskwonohjun@gmail.com)
// All rights reserved.

// Binary conversion functions: BIN2I, BIN2L, BIN2W, I2BIN, L2BIN, W2BIN
// These convert between Harbour strings and numeric values using
// little-endian byte order (Clipper/Harbour convention).

package hbrtl

import (
	"encoding/binary"
	"five/hbrt"
)

// BIN2I(cBuffer) → nValue (16-bit signed)
func Bin2I(t *hbrt.Thread) {
	t.Frame(1, 0)
	defer t.EndProc()
	buf := padBuf(t.Local(1).AsString(), 2)
	t.RetInt(int64(int16(binary.LittleEndian.Uint16(buf))))
}

// BIN2L(cBuffer) → nValue (32-bit signed)
func Bin2L(t *hbrt.Thread) {
	t.Frame(1, 0)
	defer t.EndProc()
	buf := padBuf(t.Local(1).AsString(), 4)
	t.RetInt(int64(int32(binary.LittleEndian.Uint32(buf))))
}

// BIN2W(cBuffer) → nValue (16-bit unsigned)
func Bin2W(t *hbrt.Thread) {
	t.Frame(1, 0)
	defer t.EndProc()
	buf := padBuf(t.Local(1).AsString(), 2)
	t.RetInt(int64(binary.LittleEndian.Uint16(buf)))
}

// I2BIN(nValue) → cBuffer (16-bit signed, 2 bytes)
func I2Bin(t *hbrt.Thread) {
	t.Frame(1, 0)
	defer t.EndProc()
	buf := make([]byte, 2)
	binary.LittleEndian.PutUint16(buf, uint16(int16(t.Local(1).AsLong())))
	t.RetString(string(buf))
}

// L2BIN(nValue) → cBuffer (32-bit signed, 4 bytes)
func L2Bin(t *hbrt.Thread) {
	t.Frame(1, 0)
	defer t.EndProc()
	buf := make([]byte, 4)
	binary.LittleEndian.PutUint32(buf, uint32(int32(t.Local(1).AsLong())))
	t.RetString(string(buf))
}

// W2BIN(nValue) → cBuffer (16-bit unsigned, 2 bytes)
func W2Bin(t *hbrt.Thread) {
	t.Frame(1, 0)
	defer t.EndProc()
	buf := make([]byte, 2)
	binary.LittleEndian.PutUint16(buf, uint16(t.Local(1).AsLong()))
	t.RetString(string(buf))
}

// padBuf ensures the byte buffer has at least n bytes (zero-padded).
func padBuf(s string, n int) []byte {
	b := []byte(s)
	if len(b) >= n {
		return b[:n]
	}
	buf := make([]byte, n)
	copy(buf, b)
	return buf
}