Provide a migration command

[erkinalp]

Allow community administrators to migrate a community from Discord to matrix wholesale.

Inputs: Discord guild ID, matrix space address, identity provider (a matrix identity server) Outputs: freshly created matrix rooms with all users invited according to permissions Steps of operation (the ordering is significant):

• Create empty matrix rooms corresponding to channels with appropriate permissions
• Backfill messages to respective matrix rooms
• Invite matrix users with corresponding identities to those fresh matrix rooms
• Add those fresh chat rooms to the supplied space room
• DM the users to inform on migration
• Deop all the Discord users apart from the owner (order: remove roles from all users apart from the bridge and the owner, delete overwrites)
• Prune users offline for 1 day, including those with roles
• Delete all Discord roles
• Delete all messages from Discord side, from oldest to newest (this step is not redundant as channel delete does not immediately delete all the messages)
• Delete all Discord channels
• Kick all Discord users apart from the owner

Option switches:

• No-delete: do not delete the Discord side.
• Delay-delete: delete the Discord side past a specified time after pruning the users.
• Use existing matrix chat rooms
• Create a fresh space room

[HansJK]

We really need this!

Option switches +:

• Choose not to prune users offline for 1 day, including those with roles.
• Choose not to delete roles.

[erkinalp]

Choose not to prune users offline for 1 day, including those with roles. Choose not to delete roles.

No-delete would do the combination of both, in addition to not deleting the messages and channels.

[erlend-sh]

Some prior art: https://github.com/Linen-dev/linen.dev https://github.com/Linen-dev/linen.dev/tree/main/apps/web/services/discord