/** Read-only companion HUD for the pinned, unchanged Buster GAME.X.
 * Locate its relocated text using three independent instruction signatures.
 * Addresses below are link-relative symbols, never fixed guest load addresses.
 */
export type GuestMemory={peekByte(address:number):number;peekWord(address:number):number};
const signature=Uint8Array.from('302f00066c0470ff600a4a406f047001600270004e75'.match(/../g)!.map(x=>parseInt(x,16)));
export class SwordMeter {
  base:number|null=null;private scan=0x10b12;
  constructor(private memory:GuestMemory){}
  private matches(address:number,bytes:Uint8Array){return bytes.every((b,i)=>this.memory.peekByte(address+i)===b);}
  locate(){
    const end=Math.min(this.scan+0x10000,0x200000);
    for(;this.scan<end;this.scan+=2){
      if(this.memory.peekWord(this.scan)!==0x302f||!this.matches(this.scan,signature))continue;
      const base=this.scan-0x10b12;
      if(base<0||base+0x1bac9>=0x200000)continue;
      const operand=this.memory.peekWord(base+0x206c)*65536+this.memory.peekWord(base+0x206e);
      if(operand!==base+0x1a060||this.memory.peekWord(base+0x2fb8)!==0x48e7||this.memory.peekWord(base+0x2062)!==0x4e56)continue;
      this.base=base;return true;
    }
    if(this.scan>=0x200000)this.scan=0x10b12;
    return false;
  }
  read(){
    if(this.base===null&&!this.locate())return null;
    const base=this.base!,charge=this.memory.peekByte(base+0x1a060),state=this.memory.peekByte(base+0x1babc),latched=this.memory.peekByte(base+0x1bac6)!==0,lives=this.memory.peekByte(base+0x1a074);
    if(charge>40||state>4||!lives)return null;
    const swinging=state>=1&&state<=3;
    const text=charge<8?'CHARGING':swinging?'SWINGING':state!==0?'BUSY':latched?'RELEASE & PRESS':'READY';
    return {base,charge,max:40,percent:Math.round(charge*2.5),state,lives,latched,ready:charge>=8&&state===0&&!latched,text};
  }
}