#!/usr/bin/env python3

import hashlib
import os
import sys
import time
from contextlib import contextmanager
from pathlib import Path

import psycopg
import requests
from dotenv import load_dotenv

from blacklist import (
    EXCLUDE_DIR_NAMES,
    EXCLUDE_FILENAME_KEYWORDS,
    EXCLUDE_PATH_PARTS,
    SENSITIVE_LITERAL_MARKERS,
    SENSITIVE_REGEX_PATTERNS,
)

load_dotenv(Path(__file__).parent.parent.parent / '.env.memory')
VAULT_ROOT = Path(os.getenv('VAULT_DIR', '.')).resolve()


def require_env(name: str) -> str:
    value = os.getenv(name, '').strip()
    if not value:
        raise RuntimeError(f'缺少必需环境变量: {name}')
    return value


def get_conn():
    return psycopg.connect(require_env('PG_DSN'))


def normalize_rel(path: Path) -> str:
    return str(path.resolve().relative_to(VAULT_ROOT)).replace('\\', '/')


def safe_rel(path: Path) -> str | None:
    try:
        return normalize_rel(path)
    except Exception:
        return None


def sha256_text(text: str) -> str:
    return hashlib.sha256(text.encode('utf-8')).hexdigest()


def vector_literal(values: list[float]) -> str:
    return '[' + ','.join(f'{v:.8f}' for v in values) + ']'


def _sample_head_mid_tail(content: bytes, span: int = 1200) -> str:
    size = len(content)
    if size <= span * 3:
        return content.decode('utf-8', errors='ignore').lower()
    mid = max(0, (size // 2) - (span // 2))
    sampled = content[:span] + content[mid : mid + span] + content[-span:]
    return sampled.decode('utf-8', errors='ignore').lower()


def is_excluded(file_path: Path) -> str | None:
    """返回排除原因字符串，未排除则返回 None。"""
    rel = safe_rel(file_path)
    if rel is None:
        return 'path:unresolvable'

    parts = set(Path(rel).parts)
    for name in parts.intersection(EXCLUDE_DIR_NAMES):
        return f'dir:{name}'
    for name in parts.intersection(EXCLUDE_PATH_PARTS):
        return f'path:{name}'
    for kw in EXCLUDE_FILENAME_KEYWORDS:
        if kw in file_path.name.lower():
            return f'filename:{kw}'

    try:
        snippet = _sample_head_mid_tail(file_path.read_bytes())
        for marker in SENSITIVE_LITERAL_MARKERS:
            if marker in snippet:
                return f'content:literal:{marker[:20]}'
        for pattern in SENSITIVE_REGEX_PATTERNS:
            if pattern.search(snippet):
                return f'content:regex:{pattern.pattern[:30]}'
    except Exception:
        return 'content:read_error'

    return None


@contextmanager
def index_lock():
    lock_file = Path(os.getenv('INDEX_LOCK_FILE', str(VAULT_ROOT / '.memory-index.lock')))
    lock_file.parent.mkdir(parents=True, exist_ok=True)
    with open(lock_file, 'w', encoding='utf-8') as fh:
        if sys.platform == 'win32':
            import msvcrt
            msvcrt.locking(fh.fileno(), msvcrt.LK_LOCK, 1)
            try:
                yield
            finally:
                msvcrt.locking(fh.fileno(), msvcrt.LK_UNLCK, 1)
        else:
            import fcntl as _fcntl
            _fcntl.flock(fh, _fcntl.LOCK_EX)
            try:
                yield
            finally:
                _fcntl.flock(fh, _fcntl.LOCK_UN)


def embed_text(text: str) -> list[float]:
    api_key = require_env('OPENROUTER_API_KEY')
    base_url = os.getenv('OPENROUTER_BASE_URL', 'https://openrouter.ai/api/v1').rstrip('/')
    model = require_env('OPENROUTER_EMBED_MODEL')
    expected_dim = int(os.getenv('OPENROUTER_EMBED_DIM', '1536'))

    headers = {
        'Authorization': f'Bearer {api_key}',
        'Content-Type': 'application/json',
    }
    referer = os.getenv('OPENROUTER_HTTP_REFERER', '').strip()
    if referer:
        headers['HTTP-Referer'] = referer
    title = os.getenv('OPENROUTER_X_OPENROUTER_TITLE', '').strip() or os.getenv(
        'OPENROUTER_X_TITLE', ''
    ).strip()
    if title:
        headers['X-OpenRouter-Title'] = title

    payload = {'model': model, 'input': text, 'encoding_format': 'float'}
    last_error: Exception | None = None

    for attempt in range(1, 4):
        try:
            response = requests.post(
                f'{base_url}/embeddings',
                headers=headers,
                json=payload,
                timeout=30,
            )
            response.raise_for_status()
            body = response.json()
            data = body.get('data')
            if not isinstance(data, list) or not data:
                raise RuntimeError(f'embedding 响应缺少 data 字段: keys={list(body.keys())}')
            embedding = data[0].get('embedding')
            if not isinstance(embedding, list):
                raise RuntimeError('embedding 响应结构异常: data[0].embedding 缺失')
            if len(embedding) != expected_dim:
                raise RuntimeError(
                    f'embedding 维度不匹配: got={len(embedding)} expected={expected_dim}'
                )
            return embedding
        except Exception as error:
            last_error = error
            if attempt < 3:
                time.sleep(0.8 * attempt)

    raise RuntimeError(f'OpenRouter embedding 请求失败: {last_error}') from last_error