Coding attempt

 #TouhouDanmakufu[Single]
 #ScriptVersion[3]
 #Title["My First Danmakufu Script!"]
 #Text["Code by Ender[r]My First Bullet!"]
 #BGM["./necrofantasia.ogg"]
 #include "script/default_system/Default_ShotConst.txt"
 let objBoss;
 let objScene=GetEnemyBossSceneObjectID();
@Event{
    alternative(GetEventType())
    case(EV_REQUEST_LIFE){
        SetScriptResult(500);
    }
    case(EV_REQUEST_TIMER){
        SetScriptResult(60);
    }
    case(EV_REQUEST_SPELL_SCORE){
        SetScriptResult(1000000);
    }
}
@Initialize{
    objBoss = ObjEnemy_Create(OBJ_ENEMY_BOSS);
    ObjEnemy_Regist(objBoss);
    ObjMove_SetDestAtFrame(objBoss, GetCenterX, 60, 60);
    ObjEnemyBossScene_StartSpell(objScene);
    TDrawLoop;
    TFinalize;
    MainTask;
}
@MainLoop{
    ObjEnemy_SetIntersectionCircleToShot(objBoss, ObjMove_GetX(objBoss), ObjMove_GetY(objBoss), 32);
    ObjEnemy_SetIntersectionCircleToPlayer(objBoss, ObjMove_GetX(objBoss), ObjMove_GetY(objBoss), 24);
    yield;
}

task MainTask{
    ObjMove_SetDestAtFrame(objBoss, GetCenterX(), 60, 60)
    wait(120);
    while(ObjEnemy_GetInfo(objBoss, INFO_LIFE) > 0){
    CreateShotA1(ObjMove_GetX(objBoss), ObjMove_GetY(objBoss), rand(3, 6), rand(0, 360), DS_BALL_S_BLUE, 20);
    yield;
    }
}
task movement{
    while(ObjEnemy_GetInfo(objBoss, INFO_LIFE) > 0){
        ObjMove_SetDestAtFrame(objBoss, rand(GetCenterX + 90, GetCenterX - 90), rand(GetCenterY - 60, GetCenterY - 120), 60);
        wait(240);
    }
}
task fireA{
    while(ObjEnemy_GetInfo(objBoss, INFO_LIFE) > 0){
        let angleT = GetAngleToPlayer(objBoss);
        ascent(i in -1..2){
            ascent(j in 0..3){
                CreateShotA1(ObjMove_GetX(objBoss), ObjMove_GetY(objBoss), 3 - j/6, angleT + i*15, DS_RICE_M_SKY, 5);
            }
        }
        wait(120);
    }
}
task fireB{
    while(ObjEnemy_GetInfo(objBoss, INFO_LIFE) > 0){
        let angleT = GetAngleToPlayer(objBoss);
        loop(13){
            ascent(i in 0..3){
                CreateShotA1(ObjMove_GetX(objBoss), ObjMove_GetY(objBoss), 2.5 - i/3, angleT, DS_BALL_S_RED + i, 5);
            }
            angleT += 360/13;
        }
        wait(30);
    }
}
task TDrawLoop {
    let imgExRumia = GetCurrentScriptDirectory() ~ "ExRumia.png";
    ObjPrim_SetTexture(objBoss, imgExRumia);
    ObjSprite2D_SetSourceRect(objBoss, 64, 1, 127, 64);
    ObjSprite2D_SetDestCenter(objBoss);
}
task TFinalize {
    while(ObjEnemy_GetInfo(objBoss, INFO_LIFE) > 0){yield;}
    if(ObjEnemyBossScene_GetInfo(objScene, INFO_PLAYER_SHOOTDOWN_COUNT)
            +ObjEnemyBossScene_GetInfo(objScene, INFO_PLAYER_SPELL_COUNT) == 0){
        AddScore(ObjEnemyBossScene_GetInfo(objScene, INFO_SPELL_SCORE));
    }
    Obj_Delete(objBoss);
    DeleteShotAll(TYPE_ALL,TYPE_IMMEDIATE);
    SetAutoDeleteObject(true);
    CloseScript(GetOwnScriptID());
    return;
}

function rand_int(min, max){
  return round(rand(min, max))

function GetCenterX() {
 return GetStgFrameWidth() / 2;
}
function GetCenterU(){
 return GetStgFrameHeighr() / 2;
}

function wait (n){
 loop(n){yield;}
}