How to write the snowflake sql code for the following:

Context for data: we are given a pivoted table that captures the daily price for $5$ different items. The rows are snapshot dates while the price of each item is listed in a separate column.

Example format for column heads:

snapshot$\_$date $|$ Item A$|$ Item B $|$ Item C$|$ Item D $|$ Item E

Currently we are given data for all the weekdays $($Monday to Friday$)$ from $2024-01-01$ to $2024-04-30.$ The table completely skipped weekends $($no null rows$).$

Task:

Now we need to add in all the rows for all the weekends $($Saturday and Sunday$)$ and fill those rows by copying the data from the immediately previous Friday.

On top of that, we are asked to unpivot the data so that we will end up with the following unpivoted table:

Snapshot date $|$ Item Name $|$ Price

Please provide SQL code that works for snowflake SQL$.$

Additional explanation needed:

is there a way to fill in all the columns of the null rows at once instead of using a lag function per column?

since generate$\_$series$()$ doesn't work for snowflake sql$,$ what is the most efficient way to create the continous date serie?