from datetime import datetime

from flask import Blueprint, current_app, request
from flask_jwt_extended import jwt_required

from app.extensions import db
from app.ml.naive_bayes_classifier import NaiveBayesSpamClassifier
from app.models import ContentPost, DetectionConfig, SpamPredictionLog, SpamTrainingSample, User
from app.utils.auth import current_user
from app.utils.response import fail, ok


content_bp = Blueprint("content", __name__)


def _classifier() -> NaiveBayesSpamClassifier:
    return NaiveBayesSpamClassifier(current_app.config["NB_MODEL_PATH"])


def _active_samples() -> list[dict]:
    rows = SpamTrainingSample.query.filter_by(is_active=True).order_by(SpamTrainingSample.id.asc()).all()
    return [{"text": row.text, "label": row.label} for row in rows]


def _ensure_ready() -> NaiveBayesSpamClassifier:
    clf = _classifier()
    clf.ensure_ready(_active_samples())
    return clf


def _get_config() -> DetectionConfig:
    cfg = DetectionConfig.query.order_by(DetectionConfig.id.asc()).first()
    if cfg:
        return cfg

    cfg = DetectionConfig(spam_threshold=0.75)
    db.session.add(cfg)
    db.session.commit()
    return cfg


def _serialize_post(row: ContentPost) -> dict:
    payload = row.to_dict()
    payload["username"] = row.author.username if row.author else ""
    payload["nickname"] = row.author.nickname if row.author else ""
    payload["recipient_username"] = row.recipient.username if row.recipient else ""
    payload["recipient_nickname"] = row.recipient.nickname if row.recipient else ""
    payload["reviewer_username"] = row.reviewer.username if row.reviewer else ""
    return payload


def _resolve_visibility(value: str) -> str:
    key = (value or "public").strip().lower()
    return key if key in {"public", "private", "direct"} else "public"


def _resolve_recipient(payload: dict, visibility: str, current_user_id: int):
    if visibility != "direct":
        return None, None

    recipient = None
    raw_id = payload.get("recipient_user_id")
    username = (payload.get("recipient_username") or "").strip()

    if raw_id is not None and str(raw_id).strip() != "":
        try:
            recipient = User.query.get(int(raw_id))
        except Exception:
            return None, "recipient_user_id 无效"
    elif username:
        recipient = User.query.filter_by(username=username).first()

    if not recipient:
        return None, "私信发布必须指定有效接收人"
    if recipient.id == current_user_id:
        return None, "不能给自己发送私信"
    return recipient, None


def _predict_and_decide(text: str, user_credit: int = 100) -> tuple[dict, float, bool]:
    """根据用户信誉分调整阈值系数。信誉分越高，阈值越高（降低敏感度）"""
    clf = _ensure_ready()
    result = clf.predict(text)
    base_threshold = float(_get_config().spam_threshold)

    # 信誉分影响阈值系数：credit 0-200，默认100
    # credit > 100：阈值提高（降低敏感度，减少误判）
    # credit < 100：阈值降低（提高敏感度，加强拦截）
    # 系数范围：0.85 - 1.15
    credit_factor = 1.0 + (user_credit - 100) * 0.0015  # 每10分变化1.5%
    credit_factor = max(0.85, min(1.15, credit_factor))

    adjusted_threshold = base_threshold * credit_factor
    blocked = float(result["spam_probability"]) >= adjusted_threshold
    return result, adjusted_threshold, blocked


@content_bp.post("/publish")
@jwt_required()
def publish_text():
    user = current_user()
    if not user:
        return fail("用户不存在", 404)

    payload = request.get_json(silent=True) or {}
    text = (payload.get("text") or "").strip()
    visibility = _resolve_visibility(payload.get("visibility"))

    if len(text) < 2:
        return fail("发布文本至少2个字符", 400)

    recipient, err = _resolve_recipient(payload, visibility, user.id)
    if err:
        return fail(err, 400)

    result, threshold, blocked = _predict_and_decide(text, user.credit_score or 100)

    post = ContentPost(
        user_id=user.id,
        recipient_user_id=recipient.id if recipient else None,
        text=result["text"],
        visibility=visibility,
        status="blocked" if blocked else "published",
        prediction=result["prediction"],
        spam_probability=result["spam_probability"],
        ham_probability=result["ham_probability"],
        confidence=result["confidence"],
        threshold=threshold,
        reason_tokens=result["reason_tokens"],
        model_version=result.get("model_version", ""),
        manual_review_status="pending" if blocked else "none",
    )

    detect_log = SpamPredictionLog(
        user_id=user.id,
        text=result["text"],
        prediction=result["prediction"],
        spam_probability=result["spam_probability"],
        ham_probability=result["ham_probability"],
        confidence=result["confidence"],
        reason_tokens=result["reason_tokens"],
        model_version=result.get("model_version", ""),
    )

    db.session.add(post)
    db.session.add(detect_log)

    # 发布成功（未被拦截），小幅增加信誉分；被拦截则小幅减少
    if not blocked:
        user.credit_score = min(200, (user.credit_score or 100) + 1)
    else:
        user.credit_score = max(0, (user.credit_score or 100) - 2)

    db.session.commit()

    feedback = "发布成功" if not blocked else "疑似垃圾信息，系统已拦截，可提交申诉"
    return ok(
        {
            "publish_allowed": not blocked,
            "action": "published" if not blocked else "blocked",
            "feedback": feedback,
            "post": _serialize_post(post),
            "detect": result,
        },
        feedback,
    )


@content_bp.put("/posts/<int:post_id>")
@jwt_required()
def edit_post(post_id: int):
    user = current_user()
    if not user:
        return fail("用户不存在", 404)

    post = ContentPost.query.filter_by(id=post_id, user_id=user.id).first()
    if not post:
        return fail("发布记录不存在", 404)

    payload = request.get_json(silent=True) or {}
    text = (payload.get("text") or post.text).strip()
    visibility = _resolve_visibility(payload.get("visibility") or post.visibility)

    if len(text) < 2:
        return fail("发布文本至少2个字符", 400)

    recipient, err = _resolve_recipient(payload, visibility, user.id)
    if err:
        return fail(err, 400)

    result, threshold, blocked = _predict_and_decide(text, user.credit_score or 100)

    post.text = result["text"]
    post.visibility = visibility
    post.recipient_user_id = recipient.id if recipient else None
    post.status = "blocked" if blocked else "published"
    post.prediction = result["prediction"]
    post.spam_probability = result["spam_probability"]
    post.ham_probability = result["ham_probability"]
    post.confidence = result["confidence"]
    post.threshold = threshold
    post.reason_tokens = result["reason_tokens"]
    post.model_version = result.get("model_version", "")

    post.manual_review_status = "pending" if blocked else "none"
    post.manual_review_by = None
    post.manual_review_note = ""
    post.manual_review_at = None
    post.appeal_status = "none"
    post.appeal_reason = ""
    post.appeal_admin_note = ""
    post.appeal_submitted_at = None
    post.appeal_processed_at = None
    post.appeal_processed_by = None

    db.session.commit()

    feedback = "更新并重新发布成功" if not blocked else "更新后触发拦截，可提交申诉"
    return ok(
        {
            "publish_allowed": not blocked,
            "action": "published" if not blocked else "blocked",
            "feedback": feedback,
            "post": _serialize_post(post),
            "detect": result,
        },
        feedback,
    )


@content_bp.get("/posts/history")
@jwt_required()
def my_posts():
    user = current_user()
    if not user:
        return fail("用户不存在", 404)

    status = (request.args.get("status") or "").strip().lower()
    visibility = (request.args.get("visibility") or "").strip().lower()
    page = max(int(request.args.get("page", 1) or 1), 1)
    page_size = min(max(int(request.args.get("page_size", 20) or 20), 1), 100)

    query = ContentPost.query.filter_by(user_id=user.id)
    if status in {"published", "blocked"}:
        query = query.filter(ContentPost.status == status)
    if visibility in {"public", "private", "direct"}:
        query = query.filter(ContentPost.visibility == visibility)

    pagination = query.order_by(ContentPost.id.desc()).paginate(page=page, per_page=page_size, error_out=False)
    return ok(
        {
            "items": [_serialize_post(item) for item in pagination.items],
            "total": pagination.total,
            "page": page,
            "page_size": page_size,
        }
    )


@content_bp.get("/posts/inbox")
@jwt_required()
def my_inbox():
    user = current_user()
    if not user:
        return fail("用户不存在", 404)

    page = max(int(request.args.get("page", 1) or 1), 1)
    page_size = min(max(int(request.args.get("page_size", 20) or 20), 1), 100)

    pagination = (
        ContentPost.query.filter_by(recipient_user_id=user.id, visibility="direct", status="published")
        .order_by(ContentPost.id.desc())
        .paginate(page=page, per_page=page_size, error_out=False)
    )
    return ok(
        {
            "items": [_serialize_post(item) for item in pagination.items],
            "total": pagination.total,
            "page": page,
            "page_size": page_size,
        }
    )


@content_bp.delete("/posts/<int:post_id>")
@jwt_required()
def delete_post(post_id: int):
    user = current_user()
    if not user:
        return fail("用户不存在", 404)

    row = ContentPost.query.filter_by(id=post_id, user_id=user.id).first()
    if not row:
        return fail("记录不存在", 404)

    db.session.delete(row)
    db.session.commit()
    return ok({}, "记录已删除")


@content_bp.post("/posts/<int:post_id>/appeal")
@jwt_required()
def submit_appeal(post_id: int):
    user = current_user()
    if not user:
        return fail("用户不存在", 404)

    post = ContentPost.query.filter_by(id=post_id, user_id=user.id).first()
    if not post:
        return fail("发布记录不存在", 404)
    if post.status != "blocked":
        return fail("仅被拦截的信息可申诉", 400)

    payload = request.get_json(silent=True) or {}
    reason_type = (payload.get("reason_type") or "").strip()
    reason = (payload.get("reason") or "").strip()
    evidence_urls = payload.get("evidence_urls") or []

    # 如果选择了快捷理由，reason 可为空；否则至少 2 字符
    if not reason_type and len(reason) < 2:
        return fail("申诉理由至少2个字符", 400)
    if post.appeal_status == "pending":
        return fail("该记录已在申诉处理中", 400)

    post.appeal_status = "pending"
    post.appeal_reason_type = reason_type
    post.appeal_reason = reason
    post.appeal_evidence_urls = evidence_urls
    post.appeal_submitted_at = datetime.utcnow()
    post.appeal_admin_note = ""
    post.appeal_processed_at = None
    post.appeal_processed_by = None
    post.manual_review_status = "pending"
    db.session.commit()

    return ok(_serialize_post(post), "申诉提交成功")


@content_bp.get("/appeals/my")
@jwt_required()
def my_appeals():
    user = current_user()
    if not user:
        return fail("用户不存在", 404)

    page = max(int(request.args.get("page", 1) or 1), 1)
    page_size = min(max(int(request.args.get("page_size", 20) or 20), 1), 100)

    pagination = (
        ContentPost.query.filter(ContentPost.user_id == user.id, ContentPost.appeal_status != "none")
        .order_by(ContentPost.id.desc())
        .paginate(page=page, per_page=page_size, error_out=False)
    )

    return ok(
        {
            "items": [_serialize_post(item) for item in pagination.items],
            "total": pagination.total,
            "page": page,
            "page_size": page_size,
        }
    )


@content_bp.get("/posts/public")
@jwt_required(optional=True)
def public_feed():
    page = max(int(request.args.get("page", 1) or 1), 1)
    page_size = min(max(int(request.args.get("page_size", 20) or 20), 1), 100)

    pagination = (
        ContentPost.query.filter_by(visibility="public", status="published")
        .order_by(ContentPost.id.desc())
        .paginate(page=page, per_page=page_size, error_out=False)
    )
    return ok(
        {
            "items": [_serialize_post(item) for item in pagination.items],
            "total": pagination.total,
            "page": page,
            "page_size": page_size,
        }
    )