"""
Candidate Experience Expansion Vault (spec item #6).

A persistent store of everything we've learned about the candidate's usable
experience across jobs — so the system gets stronger over time and stays
consistent (a term confirmed safe on one job stays safe on the next).

Persisted to data/candidate_vault.json. Each entry:
  { term, category, source, confidence, usage_guidance, example_bullet }
    source          ∈ resume | inferred_plausible | user_confirmed | jd_expansion
    confidence      ∈ high | medium | low
    usage_guidance  ∈ safe_to_use | use_carefully | ask_user | blocked

The vault FEEDS the fit classifier:
  - user_confirmed terms      → always safe (treated as explicit)
  - blocked terms (user said no)→ always blocked
"""

from __future__ import annotations

import json
import os
from typing import Dict, List

_VAULT_PATH = "data/candidate_vault.json"

# Per spec #8: only resume_original + user_confirmed are FULLY safe. Everything
# inferred/expanded stays REVIEWABLE — the vault must never silently promote a
# risky/plausible JD term to "safe" just because it appeared in past resumes.
_FIT_TO_GUIDANCE = {
    "explicit": "safe_to_use",     # actually present in the original resume
    "plausible": "use_carefully",  # reviewable until user confirms
    "adjacent": "use_carefully",
    "risky": "ask_user",
    "blocked": "blocked",
}
_FIT_TO_SOURCE = {
    "explicit": "resume_original",
    "plausible": "inferred_plausible",
    "adjacent": "inferred_plausible",
    "risky": "risky_review",
    "blocked": "blocked",
}
_FIT_TO_CONF = {"explicit": "high", "plausible": "medium", "adjacent": "medium",
                "risky": "low", "blocked": "low"}


def load_vault(path: str = _VAULT_PATH) -> Dict[str, dict]:
    """Return {term_lower: entry}. Empty dict if none yet."""
    try:
        with open(path, encoding="utf-8") as f:
            data = json.load(f)
        return {e["term"].lower(): e for e in data.get("entries", []) if e.get("term")}
    except Exception:
        return {}


def save_vault(vault: Dict[str, dict], path: str = _VAULT_PATH) -> None:
    try:
        os.makedirs(os.path.dirname(path), exist_ok=True)
        with open(path, "w", encoding="utf-8") as f:
            json.dump({"entries": list(vault.values())}, f, ensure_ascii=False, indent=2)
    except Exception as e:
        print(f"[vault] save skipped: {e}")


def update_from_fit(verdicts, path: str = _VAULT_PATH) -> Dict[str, dict]:
    """Merge a job's FitVerdicts into the vault. user_confirmed entries are never
    downgraded by automated runs."""
    vault = load_vault(path)
    for v in verdicts:
        key = v.keyword.lower().strip()
        if not key:
            continue
        existing = vault.get(key)
        # Never overwrite a user_confirmed / user-blocked decision automatically.
        if existing and existing.get("source") == "user_confirmed":
            continue
        vault[key] = {
            "term": v.keyword,
            "category": v.category,
            "source": _FIT_TO_SOURCE.get(v.fit_status, "jd_expansion"),
            "confidence": _FIT_TO_CONF.get(v.fit_status, "low"),
            "usage_guidance": _FIT_TO_GUIDANCE.get(v.fit_status, "use_carefully"),
            "example_bullet": (existing or {}).get("example_bullet", ""),
        }
    save_vault(vault, path)
    return vault


def confirm_terms(terms: List[str], confirmed: bool = True,
                  path: str = _VAULT_PATH) -> None:
    """User explicitly confirms (or rejects) terms — the strongest signal."""
    vault = load_vault(path)
    for t in terms:
        key = t.lower().strip()
        if not key:
            continue
        e = vault.get(key, {"term": t, "category": "user", "example_bullet": ""})
        e["source"] = "user_confirmed"
        e["confidence"] = "high"
        e["usage_guidance"] = "safe_to_use" if confirmed else "blocked"
        vault[key] = e
    save_vault(vault, path)


def user_confirmed_terms(path: str = _VAULT_PATH) -> set:
    v = load_vault(path)
    return {k for k, e in v.items()
            if e.get("source") == "user_confirmed" and e.get("usage_guidance") == "safe_to_use"}


def user_blocked_terms(path: str = _VAULT_PATH) -> set:
    v = load_vault(path)
    return {k for k, e in v.items() if e.get("usage_guidance") == "blocked"}


def confirm_expansion_terms(terms: List[str], category: str = "max_ats_expansion",
                            path: str = _VAULT_PATH) -> List[str]:
    """Persist Maximum-ATS / user-confirmed expansion terms as user_confirmed so
    future resumes treat them as safe. Returns the list of newly-stored terms.

    This is the explicit-confirmation path: the user confirmed (via the extension
    "Maximum ATS Mode" / "Confirm these terms") that these are interview-supportable.
    Truly high-risk terms are still only stored when the user confirms them here —
    nothing is silently promoted by an automated run.
    """
    terms = [t for t in (terms or []) if t and t.strip()]
    if not terms:
        return []
    vault = load_vault(path)
    blocked = {k for k, e in vault.items() if e.get("usage_guidance") == "blocked"}
    stored: List[str] = []
    for t in terms:
        key = t.lower().strip()
        if not key or key in blocked:
            continue  # never override a user block
        e = vault.get(key, {"term": t, "example_bullet": ""})
        e["term"] = e.get("term") or t
        e["category"] = e.get("category") or category
        e["source"] = "user_confirmed"
        e["confidence"] = "high"
        e["usage_guidance"] = "safe_to_use"
        vault[key] = e
        stored.append(t)
    save_vault(vault, path)
    return stored


def vault_summary(path: str = _VAULT_PATH) -> dict:
    """Reporting helper: counts + the user-confirmed term list, so the UI can
    show what's been added to the vault."""
    v = load_vault(path)
    by_source: Dict[str, int] = {}
    for e in v.values():
        by_source[e.get("source", "unknown")] = by_source.get(e.get("source", "unknown"), 0) + 1
    return {
        "total": len(v),
        "by_source": by_source,
        "user_confirmed": sorted(user_confirmed_terms(path)),
        "blocked": sorted(user_blocked_terms(path)),
    }