Could Lucifer (Satan) have repented?

Was there a period of time that the devil could have repented?

Yes, I believe it's in the Great Controversy.

Look at the story of Judas, Christ gave him many chances, but he rejected Christ and chose evil at the end which led to destruction.

Yes, Judas could have repented but didn't.

Peter did repent after denying Christ three times.

I think there was even a period of time that Lucifer could have repented, but didn't.

I found the following written by EGW:

The heavenly councils pleaded with Lucifer. The Son of God presented before him the greatness, the goodness, and the justice of the Creator, and the sacred, unchanging nature of His law. God Himself had established the order of heaven; and in departing from it, Lucifer would dishonor his Maker, and bring ruin upon himself. But the warning, given in infinite love and mercy, only aroused a spirit of resistance. Lucifer allowed jealousy of Christ to prevail, and he became the more determined?. {DD 2.2}

Here is another interesting EGW quote:

Here are the trophies which Christ took up with Him and presented to the universe of heaven and the worlds that God has created. Any affection that ever they had for Lucifer, who was the covering cherub, is now destroyed. God gave him a chance to work out his character. If He had not done this, there might have been those who felt the accusation he brought against God that He didn't give him a fair chance was justified. {FW 74.3}

Here is the quote from the 1888 version of The Great Controversy:

God, in his great mercy, bore long with Lucifer. He was not immediately degraded from his exalted station when he first indulged the spirit of discontent, nor even when he began to present his false claims before the loyal angels. Long was he retained in Heaven. Again and again he was offered pardon, on condition of repentance and submission. Such efforts as only infinite love and wisdom could devise, were made to convince him of his error. The spirit of discontent had never before been known in Heaven. Lucifer himself did not at first see whither he was drifting; he did not understand the real nature of his feelings. But as his dissatisfaction was proved to be without cause, Lucifer was convinced that he was in the wrong, that the divine claims were just, and that he ought to acknowledge them as such before all Heaven. Had he done this, he might have saved himself and many angels. He had not at this time fully cast off his allegiance to God. Though he had forsaken his position as covering cherub, yet if he had been willing to return to God, acknowledging the Creator's wisdom, and satisfied to fill the place appointed him in God's great plan, he would have been re-instated in his office. But pride forbade him to submit. He persistently defended his own course, maintained that he had no need of repentance, and fully committed himself, in the great controversy, against his Maker. {GC88 495.3}