How to get the time for each bugid from mantis bugtracker for Gantt chart

[#1]

My goal is to create a gantt chart for eacht bug ticket per user, project, and user/project.

Eventually I also want to add more detail by breakingdown each bug tiket into work type

( tables mantis_plugin_ProjectManagement_work_table, mantis_plugin_ProjectManagement_target_table)

Below is part from de ERD from mantis bugtracker

I've joint these tables:

Employee:

mantis_user_table

mantis_plugin_ProjectManagement_resource_table

Projects:

mantis_project_table

mantis_project_version_table

Bugs:

mantis_bug_table

mantis_bug_text_table

mantis_plugin_ProjectManagement_work_table (defines how much time is needed for analysis, implementation etc)

mantis_plugin_ProjectManagement_target_table(defines the target date for analysis, implementation etc)

Each bug can have 0,1 or more work_table and target _table items

As a start I want to calculate the start en ending time for each bug, this is needed for the Gantt Chart.

The rule for getting the deadline/end time for each bug is

1) get target_date from mantis_plugin_ProjectManagement_target_table
if not available
2) get bug due_date or project_version date_orde, which one comes first
3) if no deadline, don't show in chart

For now the start_time for each bug can be something random.