"""Bound model-facing observations while keeping full, task-scoped evidence."""

from pathlib import Path
import re
from typing import Any

from artemis.config.constants import PLUGIN_PROMPT_TEXT_CHARS


def result_path(engine: Any, call_id: str) -> Path:
    if not re.fullmatch(r"[a-f0-9]{32}", call_id):
        raise ValueError("插件结果编号无效")
    root = Path(engine.base_dir).resolve()
    path = root / "evidence" / "plugin-results" / f"{call_id}.txt"
    if not path.resolve().is_relative_to(root):
        raise ValueError("插件结果路径超出任务目录")
    return path


def save_result_text(engine: Any, call_id: str, text: str) -> None:
    path = result_path(engine, call_id)
    path.parent.mkdir(parents=True, exist_ok=True)
    path.write_text(text, encoding="utf-8")


def bounded_result_text(
    text: str, *, call_id: str = "", limit: int = PLUGIN_PROMPT_TEXT_CHARS
) -> str:
    if len(text) <= limit:
        return text
    reference = (
        f'完整结果可用 plugin_read_result(call_id="{call_id}", offset=0) 分页读取。'
        if call_id
        else "完整结果保存在本步骤的 trace；需要目标控件时可缩小观察范围重新读取。"
    )
    notice = f"\n[观察文本已节选，原文 {len(text)} 字符。{reference}]\n"
    available = max(0, limit - len(notice))
    if not available:
        return notice[:limit]
    head = available * 3 // 4
    return text[:head] + notice + text[-(available - head) :]


def read_result_text(engine: Any, call_id: str, offset: int = 0) -> str:
    if isinstance(offset, bool) or not isinstance(offset, int) or offset < 0:
        raise ValueError("offset 必须为非负整数")
    text = result_path(engine, call_id).read_text(encoding="utf-8")
    if offset > len(text):
        raise ValueError(f"offset 超出结果长度 {len(text)}")
    end = min(len(text), offset + PLUGIN_PROMPT_TEXT_CHARS)
    return (
        f"插件结果 {call_id}，字符 {offset}:{end}/{len(text)}；"
        + (f"下一页 offset={end}" if end < len(text) else "已到结尾")
        + "\n"
        + text[offset:end]
    )