A 20 year old unmarried girl complaining of visual aura lasting for 20 minutes described as a small central disturbance in the field of vision marches towards the periphery, leaving a transient scotoma in its wake. The expanding border of that has a scintillating, dancing, or zigzag edge. This phenomena also remain visible in the dark or with the eyes closed. After the visual symptoms recede, headache develops. She gives a long standing history of stereotypic attacks. What is the most likely diagnosis?