Eg4-Inverters

Added ability to add on additional EG4 inverters.

Summary of changes

1. Data model

• Added CONF_ENTRY_INDEX = "entry_index" in Python.const.

2. Config flow: allow multiple entries and auto-assign index

• Added _next_available_index() and modified Python.async_step_user() to:
  • Auto-compute next index across existing entries.
  • Inject entry_index into the created config entry’s data.
  • Set a unique_id that includes base_url and the index to avoid duplicate aborts.
    Format: f"{DOMAIN}|{base_url}|{index}"

3. Migration for existing installs

• Implemented Python.async_migrate_entry() to backfill entry_index=1 for legacy entries without changing entry.entry_id or entities.

4. Device info naming only (no unique_id changes to entities)

• Updated Python.sensor device_info and Python.binary_sensor device_info:
  • Keep identifiers {(DOMAIN, entry.entry_id)} to preserve device binding.
  • Device name is:
    • EG4 Inverter for index 1 (migrated)
    • EG4 Inverter {index} for index > 1

Preserved stability

• Entities’ unique_ids continue to be based on entry.entry_id and are unchanged, so history and associations remain intact for existing setups.

How this addresses the original issue

• Previously, config flow unique_id was based on title and caused Home Assistant to abort when a second inverter with the same base URL was added. Now, unique_id includes the auto-assigned index, so multiple config entries can co-exist.
• Devices are displayed distinctly: EG4 Inverter (first) and EG4 Inverter 2 (second), etc.
• All sensors are grouped under the correct device and remain uniquely identified.

What to test

• Restart Home Assistant to apply migration; verify existing device remains EG4 Inverter with entities intact.
• Add a second entry with same/different credentials as needed; confirm device shows as EG4 Inverter 2 and entities appear correctly.
• Optionally add a third to confirm EG4 Inverter 3.
• Remove and re-add entries; index will keep incrementing by max+1 (current strategy).

Files modified

• Python.const
• Python.config_flow
• Python.init
• Python.sensor
• Python.binary_sensor

Documentation note

• Add a README section: Multiple Inverters
  • Existing installs become index 1 automatically.
  • Adding another inverter will create EG4 Inverter 2, 3, …
  • Entity names remain the same; use device name to distinguish in UI.

Full Changelog: https://github.com/Trixanna/EG4-Inverter/commits/v1.1.0