module.exports = {
    begin(creep){
        if(!creep.memory.collecting) creep.memory.collecting = false;
        if(!creep.memory.counter) creep.memory.counter = 0;
    },
    
    tick(creep){
        if(creep.memory.collecting) {            
            withdrawEnergy(creep);
            energyFullCheck(creep);
        }
        else {
            transferEnergy(creep);
            energyEmptyCheck(creep);
        }
    }
}

function withdrawEnergy(creep){
    if(!creep.memory.target) findWithdrawTarget(creep);
    const target = Game.getObjectById(creep.memory.target);
    if(!target) creep.memory.target = undefined;
    if(creep.pos.isNearTo(target)) {
        if(!target.store) creep.pickup(target);
        else creep.withdraw(target, RESOURCE_ENERGY);
    }
    else creep.moveTo(target);
}

function energyFullCheck(creep){
    if(!creep.store.getFreeCapacity(RESOURCE_ENERGY)) {
        creep.memory.collecting = false;
        creep.memory.target = undefined; 
    }
}

function transferEnergy(creep){
    if(!creep.memory.target) findTransferTarget(creep);
    if(!creep.memory.target) return;
    const target = Game.getObjectById(creep.memory.target);
    if(target.store.getFreeCapacity(RESOURCE_ENERGY)==0) { creep.memory.target = undefined; creep.memory.counter++; }   
    if(creep.pos.isNearTo(target)) creep.transfer(target, RESOURCE_ENERGY);
    else creep.moveTo(target);
}

function energyEmptyCheck(creep){
    if(!creep.store.getUsedCapacity(RESOURCE_ENERGY)) {
        creep.memory.collecting = true;
        creep.memory.target = undefined; 
    }
}

function findWithdrawTarget(creep){
    var target = creep.pos.findClosestByRange(FIND_DROPPED_RESOURCES, {
        filter: (r)=>{ 
            return r.resourceType == RESOURCE_ENERGY && r.amount > creep.store.getFreeCapacity(RESOURCE_ENERGY);
        }});    
    if(!target) target = creep.pos.findClosestByRange(FIND_RUINS, {
        filter: (r)=>{ 
            return r.store.getUsedCapacity(RESOURCE_ENERGY) > creep.store.getFreeCapacity(RESOURCE_ENERGY);
        }});    
    if(!target) target = creep.pos.findClosestByRange(FIND_TOMBSTONES, {
        filter: (t)=>{ 
            return t.store.getUsedCapacity(RESOURCE_ENERGY) > creep.store.getFreeCapacity(RESOURCE_ENERGY);
        }});
    if(!target) target = creep.pos.findClosestByRange(FIND_STRUCTURES, {
        filter: (st)=>{ 
            return st.structureType == STRUCTURE_CONTAINER && st.store.getUsedCapacity(RESOURCE_ENERGY) > 1000;
        }});
    if(target) creep.memory.target = target.id;
}

function findTransferTarget(creep) {
    var target;
    switch (creep.memory.counter%3) {
        case 0: target = creep.pos.findClosestByRange(FIND_MY_STRUCTURES, {
            filter:(s)=> { 
                return (s.structureType == STRUCTURE_SPAWN || s.structureType == STRUCTURE_EXTENSION) 
                && s.store.getFreeCapacity(RESOURCE_ENERGY) > 0;
            }}); 
            break;
        case 1: target = creep.pos.findClosestByRange(FIND_STRUCTURES, {
            filter:(s)=> { 
                return s.structureType == STRUCTURE_CONTAINER 
                && s.store.getFreeCapacity(RESOURCE_ENERGY) > 1000;
            }}); 
            break;
        case 2: target = creep.room.storage; break;
    }
    if(target) creep.memory.target = target.id;
    creep.memory.counter++;
}