"""
Migration script for Phase 2 MVP fields:
- subjects.is_short_course (BOOLEAN DEFAULT 0)
- student_enrollments.allow_same_day_exception (BOOLEAN DEFAULT 0)
- student_enrollments.exception_reason (VARCHAR(255))
"""
import sqlite3
import os

def migrate():
    db_paths = [
        os.path.join(os.path.dirname(__file__), 'instance', 'app.db'),
        os.path.join(os.path.dirname(__file__), 'app.db')
    ]
    for db_path in db_paths:
        if not os.path.exists(db_path):
            continue
        print(f"Migrating SQLite DB: {db_path}")
        conn = sqlite3.connect(db_path)
        cursor = conn.cursor()

        # Check subjects.is_short_course
        cursor.execute("PRAGMA table_info(subjects)")
        columns = [row[1] for row in cursor.fetchall()]
        if 'is_short_course' not in columns:
            print("Adding column 'is_short_course' to subjects table...")
            cursor.execute("ALTER TABLE subjects ADD COLUMN is_short_course BOOLEAN DEFAULT 0")

        # Check student_enrollments.allow_same_day_exception
        cursor.execute("PRAGMA table_info(student_enrollments)")
        enr_columns = [row[1] for row in cursor.fetchall()]
        if 'allow_same_day_exception' not in enr_columns:
            print("Adding column 'allow_same_day_exception' to student_enrollments table...")
            cursor.execute("ALTER TABLE student_enrollments ADD COLUMN allow_same_day_exception BOOLEAN DEFAULT 0")
        if 'exception_reason' not in enr_columns:
            print("Adding column 'exception_reason' to student_enrollments table...")
            cursor.execute("ALTER TABLE student_enrollments ADD COLUMN exception_reason VARCHAR(255)")

        conn.commit()
        conn.close()
        print(f"Migration completed for {db_path}")

if __name__ == '__main__':
    migrate()