"""In-memory transcript of the patient chat shown by the console (kept in Streamlit session state).

Entries are plain dicts: `{"dir": "out", "text", "kind", "buttons"}` for bot replies (the `Reply` contract)
and `{"dir": "in", "text", "pressed": bool}` for what the patient sent.
"""

from __future__ import annotations

from collections.abc import Iterable
from typing import Any

MAX_ENTRIES = 400


def normalize_reply(raw: dict[str, Any]) -> dict[str, Any]:
    """Coerce an API reply into a safe shape: missing fields get defaults, malformed buttons are dropped."""
    rows: list[list[dict[str, str]]] = []
    for row in raw.get("buttons") or []:
        if not isinstance(row, list):
            continue
        clean = [
            {"label": str(b.get("label", "")), "data": str(b.get("data", ""))}
            for b in row
            if isinstance(b, dict) and b.get("data") is not None
        ]
        if clean:
            rows.append(clean)
    return {
        "dir": "out",
        "text": str(raw.get("text") or ""),
        "kind": str(raw.get("kind") or "normal"),
        "buttons": rows,
    }


class ChatLog:
    """Wraps a list owned by the caller (session state), so every page sees the same transcript."""

    def __init__(self, entries: list[dict[str, Any]] | None = None):
        self.entries: list[dict[str, Any]] = entries if entries is not None else []

    def _trim(self) -> None:
        if len(self.entries) > MAX_ENTRIES:
            del self.entries[: len(self.entries) - MAX_ENTRIES]

    def add_in(self, text: str, *, pressed: bool = False) -> None:
        self.entries.append({"dir": "in", "text": text, "pressed": pressed})
        self._trim()

    def add_replies(self, replies: Iterable[dict[str, Any]]) -> list[dict[str, Any]]:
        added = [normalize_reply(r) for r in replies if isinstance(r, dict)]
        self.entries.extend(added)
        self._trim()
        return added

    def add_history(self, messages: Iterable[dict[str, Any]]) -> None:
        """Prefill from `GET /dialog/{token}/history` (MessageOut: no buttons)."""
        for m in messages:
            if not isinstance(m, dict):
                continue
            if m.get("direction") == "in":
                self.entries.append({"dir": "in", "text": str(m.get("text", "")), "pressed": False})
            else:
                self.entries.append(normalize_reply({"text": m.get("text"), "kind": m.get("kind")}))
        self._trim()

    def recent_replies(self, n: int = 10) -> list[dict[str, Any]]:
        """Last `n` bot replies, oldest first."""
        outs = [e for e in self.entries if e.get("dir") == "out"]
        return outs[-n:] if n > 0 else []

    def last_buttons_index(self) -> int | None:
        """Index of the newest bot reply that carries buttons — only its keyboard is clickable in the web chat."""
        for i in range(len(self.entries) - 1, -1, -1):
            e = self.entries[i]
            if e.get("dir") == "out" and e.get("buttons"):
                return i
        return None

    def clear(self) -> None:
        self.entries.clear()