# ui/agent/streaming.py
from __future__ import annotations

from typing import Any

from gradio import ChatMessage

STREAM_CHUNK_SIZE = 40


def _chunk_end_indices(text: str) -> list[int]:
    if not text:
        return []
    indices = list(range(STREAM_CHUNK_SIZE, len(text), STREAM_CHUNK_SIZE))
    if not indices or indices[-1] != len(text):
        indices.append(len(text))
    return indices


def yield_streaming_string(text: str, globe_state: dict[str, Any]):
    if not text:
        yield "", globe_state
        return
    for end in _chunk_end_indices(text):
        yield text[:end], globe_state


def yield_streaming_messages(
    ui_messages: list[ChatMessage],
    text: str,
    globe_state: dict[str, Any],
    *,
    assistant_metadata: dict[str, Any] | None = None,
):
    messages = list(ui_messages)
    metadata = dict(assistant_metadata or {})
    if not text:
        messages.append(ChatMessage(role="assistant", content="", metadata=metadata or None))
        yield messages, globe_state
        return

    messages.append(ChatMessage(role="assistant", content="", metadata=metadata or None))
    for end in _chunk_end_indices(text):
        messages[-1] = ChatMessage(
            role="assistant",
            content=text[:end],
            metadata=metadata or None,
        )
        yield messages, globe_state


def yield_response(
    ui_messages: list[ChatMessage],
    text: str,
    globe_state: dict[str, Any],
    *,
    assistant_metadata: dict[str, Any] | None = None,
):
    if ui_messages:
        yield from yield_streaming_messages(
            ui_messages,
            text,
            globe_state,
            assistant_metadata=assistant_metadata,
        )
    else:
        yield from yield_streaming_string(text, globe_state)