"""Incremental evidence analysis and input-bound reuse; no page operations."""
from __future__ import annotations

import hashlib
import json
from typing import Any, Callable

from backend.browser.llm_factory import get_llm_config
from backend.prospecting.evidence_context import related_context


def fingerprint(value: Any) -> str:
    return hashlib.sha256(json.dumps(value, ensure_ascii=False, sort_keys=True, default=str).encode()).hexdigest()


def analysis_inputs(task: dict, brief) -> tuple[list[dict], dict[str, str]]:
    artifacts = task.get("artifacts") or {}
    corrections = {row.get("source_id"): row.get("text") for row in artifacts.get("corrections") or []}
    sources = [{**row, **({"user_correction": corrections[row["source_id"]]} if corrections.get(row.get("source_id")) else {})}
               for row in artifacts.get("sources") or []]
    criteria = brief.model_dump(exclude={"target_candidates", "discovery_scope", "max_notes", "max_comments_per_note", "use_web_search"})
    cfg = get_llm_config()
    signatures = {}
    for source in sources:
        context = related_context([source], sources)
        signatures[source["source_id"]] = fingerprint([1, cfg["provider"], cfg["model"], criteria, source, context])
    return sources, signatures


def analysis_is_current(task: dict, brief) -> bool:
    sources, signatures = analysis_inputs(task, brief)
    artifacts = task.get("artifacts") or {}
    saved = (artifacts.get("analysis_cache") or {}).get("source_signatures") or {}
    decisions = {row.get("source_id") for row in artifacts.get("decisions") or []}
    return bool(sources) and signatures == saved and decisions == set(signatures)


async def analyze_evidence(task: dict, brief, analyzer: Callable, *, force: bool = False) -> dict:
    sources, signatures = analysis_inputs(task, brief)
    if not sources:
        raise ValueError("当前没有已保存资料可供分析")
    artifacts = task.get("artifacts") or {}
    saved = (artifacts.get("analysis_cache") or {}).get("source_signatures") or {}
    old = {row["source_id"]: row for row in artifacts.get("decisions") or [] if row.get("source_id")}
    pending = [source for source in sources if force or saved.get(source["source_id"]) != signatures[source["source_id"]]]
    pending_ids = {source["source_id"] for source in pending}
    pending.extend(source for source in sources if source["source_id"] not in old and source["source_id"] not in pending_ids)
    result = await analyzer(brief, pending, context_sources=sources) if pending else {}
    merged = {**old, **{row["source_id"]: row for row in result.get("decisions") or []}}
    if set(signatures) - set(merged):
        raise ValueError("已保存资料尚未全部形成有效判断，原结果保留")
    decisions = [merged[source["source_id"]] for source in sources]
    leads = [{**decision, "id": decision["source_id"], "status": "pending"}
             for decision in decisions if decision.get("decision") == "keep"]
    return {**result, "decisions": decisions, "leads": leads,
            "analysis_goal_version": task.get("inputs", {}).get("_goal_version", 1),
            "analysis_cache": {"version": 1, "source_signatures": signatures},
            "analysis_reused_count": len(sources) - len(pending),
            "analysis_new_count": len(pending), "analysis_cached": not pending}