Import feature : allow to import multiple stories ?

[robindemourat]

When creating a story and clicking on "import an existing story", we could (quite easily I guess) allow to import multiple stories JSON files in one operation (instead of a single one currently).

This would allow to meet the possible need to "preload" example stories in a fonio instance as such :

1. at the end of a semester, we archive and save with quinoa-bocal the best stories then download them as a bundle of JSON file
2. we store them somewhere ex. on google drive
3. next year, in their own instances, the teachers can import these stories in a single drag-and-drop before the course start

This would be a light and souple way to allow to display example stories to students.

@audreybaneyx I put this in the tool roadmap as one possible way to address our discussion of this morning !

[robindemourat]

Changes to do for that are more important than expected because of the possibility for a story to be duplicated. Right now in the redux state we store separately a newStory for the currently imported story, overrideImport, and overrideStoryMode properties. If a story is a duplicate (i.e. there is already a story in the same id in the instance):

1. a first modal asks for an override decision (override, duplicate, or cancel)
2. a second modal asks for a password (this step occurs even when the imported story is not a duplicate)
3. then the story is possibly created on the server

This way of doing allows to handle one single story per import, but not several.

The workflow for that should be different, maybe roughly as following:

1. after drop, we store each imported story in a single importedStories array in the HomeView store part, checking for each candidate if it is a duplicate and store that info in the store (it would look like that : importedStories: [{storyId: "id", storyIsDuplicate: true, storyData: {...}},...])
2. we "unstack" the list of candidates one by one, doing steps 1, 2, and 3 one by one and displaying related modals if their state requires it. The server story creation success action should "filter out" the related story from the importedStories array - this mecanism happens as long as the importedStories array is not empty