"""评测用对话文本格式化（稳定 Turn 标签、便于评审引用）。"""

from __future__ import annotations

from typing import Any, Protocol


class _MessageLike(Protocol):
    role: str | None
    content: str | None


def assistant_text_for_eval_display(raw: str) -> str:
    """评审与 transcript 展示：避免字面量 [SPLIT] 干扰 judge 阅读。"""
    return (raw or "").replace("[SPLIT]", "\n")


def format_eval_turn_block(turn_index_0: int, user: str, assistant: str) -> str:
    """单轮回放/节选：`[Turn k]` 从 1 起计。"""
    u = (user or "").strip()
    a = assistant_text_for_eval_display(assistant).strip()
    k = int(turn_index_0) + 1
    return f"[Turn {k}]\n用户: {u}\nAI: {a}"


def format_export_turns_with_labels(turns: list[tuple[str, str]]) -> str:
    """用户导出 fixture：每轮 (user, ai)。"""
    parts: list[str] = []
    for i, (u, ai) in enumerate(turns):
        parts.append(format_eval_turn_block(i, u, ai))
    return "\n\n".join(parts)


def pair_session_messages_to_turns(
    messages: list[_MessageLike] | list[Any],
) -> list[tuple[str, str]]:
    """将对话消息序列为 (user, assistant) 轮次列表，语义与 `format_session_messages_with_turn_labels` 一致。

    末尾仅有 human、无紧随 assistant 时，补一轮 (user, "") 供 UI 与评审对齐。
    """
    out: list[tuple[str, str]] = []
    pending_user: str | None = None
    for m in messages:
        r = (getattr(m, "role", None) or "").lower()
        body = (getattr(m, "content", None) or "").strip()
        if r == "system":
            continue
        if not body and r != "human":
            continue
        if r == "human":
            pending_user = body
        elif r in ("ai", "assistant"):
            u = (pending_user or "").strip()
            pending_user = None
            out.append((u, body))
    if pending_user is not None:
        out.append((pending_user.strip(), ""))
    return out


def format_session_messages_with_turn_labels(
    messages: list[_MessageLike] | list[Any],
) -> str:
    """会话消息序列：按出现顺序将相邻 human→assistant 合并为一轮。"""
    blocks: list[str] = []
    turn_idx = 0
    pending_user: str | None = None
    for m in messages:
        r = (getattr(m, "role", None) or "").lower()
        body = (getattr(m, "content", None) or "").strip()
        if not body and r != "human":
            continue
        if r == "human":
            pending_user = body
        elif r in ("ai", "assistant", "system"):
            if r == "system":
                continue
            u = (pending_user or "").strip()
            pending_user = None
            blocks.append(format_eval_turn_block(turn_idx, u, body))
            turn_idx += 1
    return "\n\n".join(blocks)