package parser

import (
	"encoding/binary"
	"eq2emu/internal/common"
	"unsafe"
)

type ParseContext struct {
	data       []byte
	offset     int
	version    uint32
	flags      uint64
	vars       map[string]any
	arrayStack []int
}

func NewContext(data []byte, version uint32, flags uint64) *ParseContext {
	return &ParseContext{
		data:    data,
		version: version,
		flags:   flags,
		vars:    make(map[string]any),
	}
}

func (ctx *ParseContext) readUint8() uint8 {
	val := ctx.data[ctx.offset]
	ctx.offset++
	return val
}

func (ctx *ParseContext) readUint16() uint16 {
	val := binary.LittleEndian.Uint16(ctx.data[ctx.offset:])
	ctx.offset += 2
	return val
}

func (ctx *ParseContext) readUint32() uint32 {
	val := binary.LittleEndian.Uint32(ctx.data[ctx.offset:])
	ctx.offset += 4
	return val
}

func (ctx *ParseContext) readOversizedUint8(threshold int) uint8 {
	if ctx.data[ctx.offset] == byte(threshold) {
		ctx.offset++
		return ctx.readUint8()
	}
	return ctx.readUint8()
}

func (ctx *ParseContext) readOversizedUint16(threshold int) uint16 {
	if ctx.data[ctx.offset] == byte(threshold) {
		ctx.offset++
		return ctx.readUint16()
	}
	return uint16(ctx.readUint8())
}

func (ctx *ParseContext) readString8() string {
	length := ctx.readUint8()
	str := string(ctx.data[ctx.offset : ctx.offset+int(length)])
	ctx.offset += int(length)
	return str
}

func (ctx *ParseContext) readString16() string {
	length := ctx.readUint16()
	str := string(ctx.data[ctx.offset : ctx.offset+int(length)])
	ctx.offset += int(length)
	return str
}

func (ctx *ParseContext) readEQ2String8() common.EQ2String8 {
	size := ctx.readUint8()
	data := string(ctx.data[ctx.offset : ctx.offset+int(size)])
	ctx.offset += int(size)
	return common.EQ2String8{
		Size: size,
		Data: data,
	}
}

func (ctx *ParseContext) readEQ2String16() common.EQ2String16 {
	size := ctx.readUint16()
	data := string(ctx.data[ctx.offset : ctx.offset+int(size)])
	ctx.offset += int(size)
	return common.EQ2String16{
		Size: size,
		Data: data,
	}
}

func (ctx *ParseContext) readEQ2String32() common.EQ2String32 {
	size := ctx.readUint32()
	data := string(ctx.data[ctx.offset : ctx.offset+int(size)])
	ctx.offset += int(size)
	return common.EQ2String32{
		Size: size,
		Data: data,
	}
}

func (ctx *ParseContext) readEQ2Color() common.EQ2Color {
	return common.EQ2Color{
		Red:   ctx.readUint8(),
		Green: ctx.readUint8(),
		Blue:  ctx.readUint8(),
	}
}

func (ctx *ParseContext) readEQ2Equipment() common.EQ2EquipmentItem {
	return common.EQ2EquipmentItem{
		Type:      ctx.readUint16(),
		Color:     ctx.readEQ2Color(),
		Highlight: ctx.readEQ2Color(),
	}
}

func (ctx *ParseContext) readBytes(count int) []byte {
	val := make([]byte, count)
	copy(val, ctx.data[ctx.offset:ctx.offset+count])
	ctx.offset += count
	return val
}

func (ctx *ParseContext) readFloat32() float32 {
	val := ctx.readUint32()
	return *(*float32)(unsafe.Pointer(&val))
}

func (ctx *ParseContext) setVar(name string, value any) {
	ctx.vars[name] = value
}

func (ctx *ParseContext) pushArrayIndex(index int) {
	ctx.arrayStack = append(ctx.arrayStack, index)
}

func (ctx *ParseContext) popArrayIndex() {
	if len(ctx.arrayStack) > 0 {
		ctx.arrayStack = ctx.arrayStack[:len(ctx.arrayStack)-1]
	}
}