package vm_debug

import (
	"encoding/json"
	"unsafe"

	"github.com/goccy/go-json/internal/encoder"
	"github.com/goccy/go-json/internal/runtime"
)

func load(base uintptr, idx uintptr) uintptr {
	addr := base + idx
	return **(**uintptr)(unsafe.Pointer(&addr))
}

func store(base uintptr, idx uintptr, p uintptr) {
	addr := base + idx
	**(**uintptr)(unsafe.Pointer(&addr)) = p
}

func loadNPtr(base uintptr, idx uintptr, ptrNum int) uintptr {
	addr := base + idx
	p := **(**uintptr)(unsafe.Pointer(&addr))
	for i := 0; i < ptrNum; i++ {
		if p == 0 {
			return 0
		}
		p = ptrToPtr(p)
	}
	return p
}

func ptrToUint64(p uintptr) uint64              { return **(**uint64)(unsafe.Pointer(&p)) }
func ptrToFloat32(p uintptr) float32            { return **(**float32)(unsafe.Pointer(&p)) }
func ptrToFloat64(p uintptr) float64            { return **(**float64)(unsafe.Pointer(&p)) }
func ptrToBool(p uintptr) bool                  { return **(**bool)(unsafe.Pointer(&p)) }
func ptrToBytes(p uintptr) []byte               { return **(**[]byte)(unsafe.Pointer(&p)) }
func ptrToNumber(p uintptr) json.Number         { return **(**json.Number)(unsafe.Pointer(&p)) }
func ptrToString(p uintptr) string              { return **(**string)(unsafe.Pointer(&p)) }
func ptrToSlice(p uintptr) *runtime.SliceHeader { return *(**runtime.SliceHeader)(unsafe.Pointer(&p)) }
func ptrToPtr(p uintptr) uintptr {
	return uintptr(**(**unsafe.Pointer)(unsafe.Pointer(&p)))
}
func ptrToNPtr(p uintptr, ptrNum int) uintptr {
	for i := 0; i < ptrNum; i++ {
		if p == 0 {
			return 0
		}
		p = ptrToPtr(p)
	}
	return p
}

func ptrToUnsafePtr(p uintptr) unsafe.Pointer {
	return *(*unsafe.Pointer)(unsafe.Pointer(&p))
}
func ptrToInterface(code *encoder.Opcode, p uintptr) interface{} {
	return *(*interface{})(unsafe.Pointer(&emptyInterface{
		typ: code.Type,
		ptr: *(*unsafe.Pointer)(unsafe.Pointer(&p)),
	}))
}

func appendBool(b []byte, v bool) []byte {
	if v {
		return append(b, "true"...)
	}
	return append(b, "false"...)
}

func appendNull(b []byte) []byte {
	return append(b, "null"...)
}

func appendComma(b []byte) []byte {
	return append(b, ',')
}

func appendStructEnd(b []byte) []byte {
	return append(b, '}', ',')
}

func appendStructEndSkipLast(b []byte) []byte {
	last := len(b) - 1
	if b[last] == ',' {
		b[last] = '}'
		return appendComma(b)
	}
	return appendStructEnd(b)
}