import os
import re
import time
from concurrent.futures import ThreadPoolExecutor
from datetime import datetime
from urllib.parse import urlparse

import psycopg2
import requests
from bs4 import BeautifulSoup
from dotenv import load_dotenv
from flask import Flask, jsonify, make_response, render_template, request, send_from_directory

load_dotenv()

app = Flask(__name__, static_folder="static", template_folder="templates")


DEFAULT_DESCRIPTION = "설명 없음"
DEFAULT_IMAGE = "/static/placeholder.svg"
CACHE_TTL_SECONDS = int(os.getenv("CACHE_TTL_SECONDS", "3600"))
FAILED_TTL_SECONDS = int(os.getenv("FAILED_TTL_SECONDS", "300"))
METADATA_CACHE = {}
TABLE_COLUMNS_CACHE = {}
PLACEHOLDER_DATA_URI = (
    "data:image/svg+xml;utf8,"
    "<svg%20width='640'%20height='360'%20viewBox='0%200%20640%20360'%20fill='none'%20"
    "xmlns='http://www.w3.org/2000/svg'>"
    "<rect%20width='640'%20height='360'%20fill='%23e9ecef'/>"
    "<rect%20x='120'%20y='90'%20width='400'%20height='180'%20rx='16'%20fill='%23dee2e6'/>"
    "<path%20d='M210%20210l60-70%2070%2080%2060-60%2090%2090H210z'%20fill='%23adb5bd'/>"
    "<circle%20cx='260'%20cy='150'%20r='22'%20fill='%23adb5bd'/>"
    "<text%20x='320'%20y='260'%20text-anchor='middle'%20font-size='18'%20"
    "fill='%236c757d'%20font-family='Arial,%20sans-serif'>No%20Image</text>"
    "</svg>"
)
DEFAULT_PAGE_SIZE = int(os.getenv("DEFAULT_PAGE_SIZE", "30"))
MAX_PAGE_SIZE = int(os.getenv("MAX_PAGE_SIZE", "60"))
DEFAULT_SCHEMA = os.getenv("DB_SCHEMA", "public")


def _safe_identifier(name: str) -> str:
    if not name or not re.match(r"^[A-Za-z_][A-Za-z0-9_]*$", name):
        raise ValueError(f"Invalid SQL identifier: {name!r}")
    return name


def _table_ref(schema: str, table: str) -> str:
    return f"{_safe_identifier(schema)}.{_safe_identifier(table)}"


def get_db_connection():
    return psycopg2.connect(
        host=os.getenv("DB_HOST"),
        port=os.getenv("DB_PORT"),
        dbname=os.getenv("DB_NAME"),
        user=os.getenv("DB_USER"),
        password=os.getenv("DB_PASSWORD"),
    )


def normalize_url(raw_url: str) -> str:
    if not raw_url:
        return raw_url
    parsed = urlparse(raw_url)
    if parsed.scheme:
        return raw_url
    return f"https://{raw_url}"


def extract_meta(soup: BeautifulSoup, property_name: str, name: str):
    tag = soup.find("meta", property=property_name)
    if tag and tag.get("content"):
        return tag.get("content").strip()
    tag = soup.find("meta", attrs={"name": name})
    if tag and tag.get("content"):
        return tag.get("content").strip()
    return ""


def extract_fallback_description(soup: BeautifulSoup) -> str:
    for paragraph in soup.find_all("p"):
        text = paragraph.get_text(" ", strip=True)
        if len(text) >= 40:
            return text[:180]
    return ""


def fetch_metadata(url: str):
    fallback = {
        "title": url,
        "description": DEFAULT_DESCRIPTION,
        "image": DEFAULT_IMAGE,
    }
    cached = METADATA_CACHE.get(url)
    now = time.time()
    if cached and cached["expires_at"] > now:
        return cached["data"]
    try:
        response = requests.get(
            url,
            headers={
                "User-Agent": (
                    "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) "
                    "AppleWebKit/537.36 (KHTML, like Gecko) "
                    "Chrome/121.0.0.0 Safari/537.36"
                )
            },
            timeout=6,
        )
        response.raise_for_status()
        soup = BeautifulSoup(response.text, "html.parser")
        resolved_url = response.url or url

        title = (
            extract_meta(soup, "og:title", "twitter:title")
            or extract_meta(soup, "twitter:title", "title")
            or (soup.title.string.strip() if soup.title and soup.title.string else "")
            or resolved_url
        )
        description = (
            extract_meta(soup, "og:description", "description")
            or extract_meta(soup, "twitter:description", "description")
        )
        if not description:
            description = extract_fallback_description(soup) or DEFAULT_DESCRIPTION
        image = (
            extract_meta(soup, "og:image", "twitter:image")
            or extract_meta(soup, "twitter:image", "image")
            or DEFAULT_IMAGE
        )
        data = {"title": title, "description": description, "image": image}
        METADATA_CACHE[url] = {
            "data": data,
            "expires_at": now + CACHE_TTL_SECONDS,
            "ok": True,
        }
        return data
    except Exception:
        METADATA_CACHE[url] = {
            "data": fallback,
            "expires_at": now + FAILED_TTL_SECONDS,
            "ok": False,
        }
        return fallback


def _clamp_int(value, default: int, minimum: int, maximum: int) -> int:
    try:
        parsed = int(value)
    except Exception:
        return default
    return max(minimum, min(parsed, maximum))


def get_table_columns(schema: str, table: str):
    key = (schema, table)
    cached = TABLE_COLUMNS_CACHE.get(key)
    if cached is not None:
        return cached

    with get_db_connection() as conn:
        with conn.cursor() as cur:
            cur.execute(
                """
                SELECT column_name
                FROM information_schema.columns
                WHERE table_schema = %s AND table_name = %s
                """,
                (schema, table),
            )
            cols = {row[0] for row in cur.fetchall()}

    TABLE_COLUMNS_CACHE[key] = cols
    return cols


def get_table_columns_info(schema: str, table: str):
    key = ("info", schema, table)
    cached = TABLE_COLUMNS_CACHE.get(key)
    if cached is not None:
        return cached

    with get_db_connection() as conn:
        with conn.cursor() as cur:
            cur.execute(
                """
                SELECT column_name, data_type, udt_name, is_nullable
                FROM information_schema.columns
                WHERE table_schema = %s AND table_name = %s
                """,
                (schema, table),
            )
            info = {
                row[0]: {
                    "data_type": row[1],
                    "udt_name": row[2],
                    "is_nullable": row[3],
                }
                for row in cur.fetchall()
            }

    TABLE_COLUMNS_CACHE[key] = info
    return info


def get_request_identity(req) -> tuple[str | None, str | None]:
    """
    가능한 경우 (email, ip)를 반환.
    - 이메일: 프록시/SSO가 주입하는 헤더에서 추출
    - IP: X-Forwarded-For / X-Real-IP / remote_addr 순
    """
    # 0) ncue.net/go 연동: ref_type/ref 를 쿼리스트링 또는 쿠키로 전달받을 수 있음
    ref_type = (req.args.get("ref_type") or req.cookies.get("ref_type") or "").strip()
    ref = (req.args.get("ref") or req.cookies.get("ref") or "").strip()
    if ref_type in ("email", "ip") and ref:
        if ref_type == "email":
            return ref, None
        return None, ref

    email_headers = [
        "X-User-Email",
        "X-Forwarded-Email",
        "X-Auth-Request-Email",
        "X-Forwarded-User",
        "Remote-User",
        "X-Email",
    ]
    email = None
    for h in email_headers:
        v = (req.headers.get(h) or "").strip()
        if v and "@" in v:
            email = v
            break

    xff = (req.headers.get("X-Forwarded-For") or "").strip()
    if xff:
        ip = xff.split(",")[0].strip()
    else:
        ip = (req.headers.get("X-Real-IP") or "").strip() or (req.remote_addr or "")
    ip = ip.strip() or None
    return email, ip


def _maybe_set_ref_cookies(resp):
    ref_type = (request.args.get("ref_type") or "").strip()
    ref = (request.args.get("ref") or "").strip()
    if ref_type in ("email", "ip") and ref:
        # JS 요청(/links)에서도 유지되도록 쿠키 저장 (SameSite=Lax)
        max_age = 60 * 60 * 24 * 30  # 30일
        resp.set_cookie("ref_type", ref_type, max_age=max_age, samesite="Lax")
        resp.set_cookie("ref", ref, max_age=max_age, samesite="Lax")
    return resp


def fetch_links_page_from_db(limit: int, offset: int):
    table = os.getenv("TABLE", "news_link")
    schema = os.getenv("DB_SCHEMA", DEFAULT_SCHEMA)
    table_ref = _table_ref(schema, table)
    with get_db_connection() as conn:
        with conn.cursor() as cur:
            cur.execute(
                f"SELECT id, url, created_at FROM {table_ref} ORDER BY created_at DESC OFFSET %s LIMIT %s",
                (offset, limit),
            )
            return cur.fetchall()


@app.get("/")
def index():
    links = []
    error_message = ""
    try:
        rows = fetch_links_page_from_db(DEFAULT_PAGE_SIZE, 0)
        for link_id, url, created_at in rows:
            links.append(
                {
                    "id": link_id,
                    "url": url,
                    "created_at": created_at.isoformat()
                    if isinstance(created_at, datetime)
                    else str(created_at),
                    "title": "",
                    "description": "",
                    "image": "",
                }
            )
    except Exception as exc:
        error_message = f"DB 조회 실패: {exc}"
    resp = make_response(
        render_template(
        "index.html",
        links=links,
        error_message=error_message,
        placeholder_data_uri=PLACEHOLDER_DATA_URI,
        default_image=DEFAULT_IMAGE,
        )
    )
    return _maybe_set_ref_cookies(resp)


@app.get("/favicon.ico")
def favicon():
    # ncue.net 등에서 /favicon.ico 로 직접 가져갈 수 있게 제공
    return send_from_directory(
        app.static_folder,
        "favicon.ico",
        mimetype="image/x-icon",
        max_age=60 * 60 * 24 * 7,
    )


@app.get("/links")
def get_links():
    limit = _clamp_int(
        request.args.get("limit"), DEFAULT_PAGE_SIZE, minimum=1, maximum=MAX_PAGE_SIZE
    )
    offset = _clamp_int(request.args.get("offset"), 0, minimum=0, maximum=10_000_000)

    try:
        rows_plus_one = fetch_links_page_from_db(limit + 1, offset)
    except Exception as exc:
        return jsonify({"error": "DB 조회 실패", "detail": str(exc)}), 500

    has_more = len(rows_plus_one) > limit
    rows = rows_plus_one[:limit]

    urls = [url for _, url, _ in rows]
    metas = []
    if urls:
        with ThreadPoolExecutor(max_workers=min(8, len(urls))) as executor:
            metas = list(executor.map(fetch_metadata, urls))

    results = []
    for (link_id, url, created_at), meta in zip(rows, metas):
        results.append(
            {
                "id": link_id,
                "url": url,
                "created_at": created_at.isoformat()
                if isinstance(created_at, datetime)
                else str(created_at),
                **meta,
            }
        )
    return jsonify(
        {
            "items": results,
            "limit": limit,
            "offset": offset,
            "next_offset": offset + len(results),
            "has_more": has_more,
        }
    )


@app.post("/links")
def add_link():
    data = request.get_json(silent=True) or {}
    raw_url = (data.get("url") or "").strip()
    if not raw_url:
        return jsonify({"error": "URL을 입력해주세요."}), 400

    url = normalize_url(raw_url)
    table = os.getenv("TABLE", "news_link")
    schema = os.getenv("DB_SCHEMA", DEFAULT_SCHEMA)
    table_ref = _table_ref(schema, table)
    try:
        cols = get_table_columns(schema, table)
        cols_info = get_table_columns_info(schema, table)
        email, ip = get_request_identity(request)
        identity = email or ip  # 이메일 우선, 없으면 IP

        insert_cols = ["url"]
        insert_vals_sql = ["%s"]
        insert_params = [url]

        # 운영 DB 스키마 호환: created_at/updated_at, author_id 등이 NOT NULL일 수 있음
        if "created_at" in cols:
            insert_cols.append("created_at")
            insert_vals_sql.append("NOW()")
        if "updated_at" in cols:
            insert_cols.append("updated_at")
            insert_vals_sql.append("NOW()")

        if "author_id" in cols:
            author_col = cols_info.get("author_id", {})
            data_type = (author_col.get("data_type") or "").lower()
            udt = (author_col.get("udt_name") or "").lower()

            # 1) author_id가 텍스트 계열이면: 이메일/아이피 문자열을 그대로 저장
            if data_type in ("text", "character varying", "character"):
                insert_cols.append("author_id")
                insert_vals_sql.append("%s")
                insert_params.append(identity or "unknown")

            # 2) author_id가 숫자(정수/숫자)면: 문자열 저장 불가
            #    → 기존 DEFAULT_AUTHOR_ID로 채우고, 가능한 경우 author_email/author_ip에 따로 저장(스키마 호환)
            elif udt in ("int2", "int4", "int8") or data_type in ("smallint", "integer", "bigint", "numeric"):
                raw_author_id = os.getenv("DEFAULT_AUTHOR_ID")
                if raw_author_id is None or str(raw_author_id).strip() == "":
                    return (
                        jsonify(
                            {
                                "error": "DB 저장 실패",
                                "detail": "author_id가 정수 NOT NULL입니다. .env에 DEFAULT_AUTHOR_ID(정수)를 설정하거나, author_id 타입을 text로 변경하세요.",
                            }
                        ),
                        500,
                    )
                try:
                    author_id_int = int(raw_author_id)
                except Exception:
                    return (
                        jsonify(
                            {
                                "error": "DB 저장 실패",
                                "detail": f"DEFAULT_AUTHOR_ID는 정수여야 합니다: {raw_author_id!r}",
                            }
                        ),
                        500,
                    )
                insert_cols.append("author_id")
                insert_vals_sql.append("%s")
                insert_params.append(author_id_int)

                if "author_email" in cols and email:
                    insert_cols.append("author_email")
                    insert_vals_sql.append("%s")
                    insert_params.append(email)
                if "author_ip" in cols and ip:
                    insert_cols.append("author_ip")
                    insert_vals_sql.append("%s")
                    insert_params.append(ip)

            # 3) 기타 타입(uuid 등): 우선 문자열을 넣되 실패 시 detail로 노출
            else:
                insert_cols.append("author_id")
                insert_vals_sql.append("%s")
                insert_params.append(identity or "unknown")

        with get_db_connection() as conn:
            with conn.cursor() as cur:
                cur.execute(
                    f"INSERT INTO {table_ref} ({', '.join(insert_cols)}) VALUES ({', '.join(insert_vals_sql)}) RETURNING id, created_at",
                    tuple(insert_params),
                )
                link_id, created_at = cur.fetchone()
                conn.commit()
    except Exception as exc:
        return jsonify({"error": "DB 저장 실패", "detail": str(exc)}), 500

    meta = fetch_metadata(url)
    return jsonify(
        {
            "id": link_id,
            "url": url,
            "created_at": created_at.isoformat()
            if isinstance(created_at, datetime)
            else str(created_at),
            **meta,
        }
    )


if __name__ == "__main__":
    app.run(host="0.0.0.0", port=8021, debug=True)