import json
from collections.abc import Iterable, Iterator
from typing import Any


VALID_TYPES = {
    "stage",
    "voice",
    "skill",
    "text_delta",
    "sentence_end",
    "vision_note",
    "audio",
    "debug",
    "done",
    "error",
}


def normalize_event(event: dict[str, Any]) -> dict[str, Any]:
    event_type = event.get("type")
    if event_type not in VALID_TYPES:
        return {"type": "debug", "message": f"unknown event type: {event_type}", "raw": event}

    if event_type == "stage":
        return {
            "type": "stage",
            "expression": event.get("expression", "idle"),
            "motion": event.get("motion", "breathe"),
            "intensity": _clamp(event.get("intensity", 0.5), 0.0, 1.0),
        }
    if event_type == "voice":
        return {
            "type": "voice",
            "style": event.get("style", "neutral"),
            "speed": _clamp(event.get("speed", 1.0), 0.6, 1.4),
            "energy": _clamp(event.get("energy", 0.5), 0.0, 1.0),
        }
    if event_type == "text_delta":
        return {"type": "text_delta", "text": str(event.get("text", ""))}
    return event


def parse_sse_lines(lines: Iterable[str]) -> Iterator[dict[str, Any]]:
    for line in lines:
        if not line:
            continue
        if line.startswith("data:"):
            line = line[5:].strip()
        if line == "[DONE]":
            yield {"type": "done"}
            continue
        try:
            parsed = json.loads(line)
        except json.JSONDecodeError:
            yield {"type": "debug", "message": "invalid json event", "raw": line}
            continue
        yield normalize_event(parsed)


def dumps_event(event: dict[str, Any]) -> str:
    return json.dumps(normalize_event(event), ensure_ascii=False)


def _clamp(value: Any, low: float, high: float) -> float:
    try:
        number = float(value)
    except (TypeError, ValueError):
        number = (low + high) / 2
    return max(low, min(high, number))