best way of automation (REST API, Plugin AUTOMATION, Script Runner for JIRA)

[Atlassianist]

Hello,

we have a Service Manager installation /Data Center/. With some months we we als have JIRA Software and Confluence ...

We have some tasks that should be automated.

• - calculating time in a custom feld
• - some more complex JQL queries and daily export as CSV, PDF
• - automatically initiate user directorie sync of a new AD user has been created
• - create new JIRA Projects if a certain Powershell Script has been excuted and created jire-specific AD-groups. /These AD-Groups have to be automatically matched to certain JIRA-Roles/
• - Start external powershell scripts if the status of a certain subtask has been changed.
• - if a user has created a certain JIRA-Task a Powershell Script has to be started and check different things in the network. 
• If a JIRA Task has certain Status, a table on a Confluence Page has to be filled with information.
• If in a Confluence Page a certain table has been editied a JIRA Ticket gets a news status.
• If a JIRA Ticket gets "done" a Confluence Page has to be exported as PDF and saved on a network share ...

I think these kind of tasks can be made only with ScriptRunner ... REST API could be a way to manages things in jira with external Scripts, it would be however no option initiate processes from JIRA and execute them outside JIRA. 

I don´t know know either how JIRA Automation could execute Scripts outside JIRA.

Do you know any other option beside ScriptRunner?

In case you have purchased Script Runner, which "UseCases" have been the reason to do so?

(Where have been the limits of the "normal" solutions, Plugins?)

Thank you very much for your feedback.

Regards

Istvan