# Workflow Chat — Starlark Backend (v0.1.0)
#
# Library package that creates scoped chat conversations when
# workflow stages require team collaboration.
#
# Usage: wire into stage_config as an on_advance hook:
#   {"on_advance": {"package_id": "workflow-chat", "entry_point": "on_advance"}}
#
# Expected stage_data keys:
#   title              — conversation title (optional, defaults to "Workflow Discussion")
#   team_members       — list of {id, display_name} dicts
#   creator_id         — user ID of the workflow initiator
#   creator_display_name — display name of the workflow initiator
#
# Modules: db, json, realtime (via chat-core dependency)

chat = lib.require("chat-core")


def _str(v):
    if v == None:
        return ""
    return str(v)


def on_advance(ctx):
    """Hook called when a workflow advances to a team-audience stage.

    Creates a group conversation with all team members and sends
    a system message linking back to the workflow instance.

    Args:
        ctx: dict with {instance_id, previous_stage, current_stage, stage_data}

    Returns:
        dict with {stage_data} containing enriched data with conversation_id,
        or None if no team members are present.
    """
    data = ctx.get("stage_data", {})
    if type(data) == "string":
        data = json.decode(data) if data else {}

    instance_id = _str(ctx.get("instance_id", ""))
    members = data.get("team_members", [])
    creator_id = _str(data.get("creator_id", ""))
    creator_name = _str(data.get("creator_display_name", ""))
    title = _str(data.get("title", "")) or "Workflow Discussion"

    # Skip if no team members to add
    if not members:
        return None

    # Check if conversation already exists for this instance (idempotency)
    existing_cid = _str(data.get("conversation_id", ""))
    if existing_cid:
        return None

    # Build participants list
    participants = []
    for m in members:
        mid = _str(m.get("id", ""))
        if mid and mid != creator_id:
            participants.append({
                "id": mid,
                "display_name": _str(m.get("display_name", "")),
            })

    # Create conversation scoped to this workflow instance
    conv = chat.create(
        title=title + " [" + instance_id[:8] + "]",
        type="group",
        participants=participants,
        creator_id=creator_id,
        creator_display_name=creator_name,
    )

    cid = _str(conv.get("id", ""))

    # Send system message linking to the workflow
    chat.send(cid, creator_id, "Conversation created for workflow instance " + instance_id, "system")

    # Return enriched stage_data with conversation_id
    enriched = {}
    for k in data:
        enriched[k] = data[k]
    enriched["conversation_id"] = cid

    return {"stage_data": enriched}