#!/usr/bin/env python2
# -*- coding: utf-8 -*-
"""Multi-engine proxy list scraper."""

import dbs
import json
import random
import time
import threading
import urllib
import mysqlite
import proxywatchd
from misc import _log
from config import Config
import fetch
import engines
import translations
import os

# State file for engine backoff persistence (in data directory for persistence)
STATE_FILE = 'data/scraper_state.json'

config = Config()

# Default search terms (can be overridden by search_terms.txt)
search_terms = ['free proxy list', 'socks5 proxy', 'http proxy']

# Load Searx instances if file exists
searx_instances = []
if os.path.exists('searx.instances'):
    with open('searx.instances') as h:
        searx_instances = [line.strip() for line in h.readlines()
                          if line.lower().startswith('http')]


class EngineTracker(object):
    """Track multiple search engine instances with rate limiting."""

    def __init__(self, engine_names, searx_urls, base_delay=30, max_delay=3600,
                 state_file=None):
        self.base_delay = base_delay
        self.max_delay = max_delay
        self.failures = {}
        self.backoff_until = {}
        self.success_count = {}
        self.last_rate_log = 0
        self.log_interval = 60  # seconds between rate-limit log messages
        self.state_file = state_file or STATE_FILE
        self._save_interval = 60  # seconds between saves
        self._last_save = 0

        # Build list of (engine_instance, identifier)
        self.engines = []
        for name in engine_names:
            name = name.strip().lower()
            if name == 'searx':
                for url in searx_urls:
                    eng = engines.Searx(url)
                    self.engines.append((eng, url))
            elif name in engines.ENGINES:
                eng = engines.get_engine(name)
                self.engines.append((eng, name))
            else:
                _log('unknown engine: %s' % name, 'warn')

        # Load persisted state
        self.load_state()

    def get_available(self):
        """Return engines not currently in backoff."""
        now = time.time()
        available = []
        for eng, ident in self.engines:
            if ident not in self.backoff_until or now >= self.backoff_until[ident]:
                available.append((eng, ident))
        return available

    def mark_success(self, ident):
        """Reset failure count on success."""
        self.failures[ident] = 0
        self.success_count[ident] = self.success_count.get(ident, 0) + 1
        if ident in self.backoff_until:
            del self.backoff_until[ident]
        self.save_state()

    def mark_failure(self, ident):
        """Increment failure count and set exponential backoff."""
        count = self.failures.get(ident, 0) + 1
        self.failures[ident] = count
        delay = min(self.base_delay * (2 ** (count - 1)), self.max_delay)
        self.backoff_until[ident] = time.time() + delay
        now = time.time()
        if (now - self.last_rate_log) >= self.log_interval:
            name = ident.split('/')[2] if '/' in ident else ident
            avail, in_backoff, total = self.get_status()
            _log('%d/%d engines in backoff (last: %s)' % (in_backoff, total, name), 'rate')
            self.last_rate_log = now
        self.save_state()
        return delay

    def get_status(self):
        """Return status summary."""
        available = len(self.get_available())
        in_backoff = len(self.engines) - available
        return available, in_backoff, len(self.engines)

    def get_stats(self):
        """Return detailed stats for API/dashboard."""
        now = time.time()
        available = self.get_available()
        available_ids = set(ident for _, ident in available)

        engines_list = []
        for eng, ident in self.engines:
            # Shorten identifier for display
            if '/' in ident:
                name = ident.split('/')[2]  # extract domain from URL
            else:
                name = ident

            backoff_remaining = 0
            if ident in self.backoff_until:
                backoff_remaining = max(0, int(self.backoff_until[ident] - now))

            engines_list.append({
                'name': name,
                'available': ident in available_ids,
                'successes': self.success_count.get(ident, 0),
                'failures': self.failures.get(ident, 0),
                'backoff_remaining': backoff_remaining
            })

        # Sort by success count descending
        engines_list.sort(key=lambda x: -x['successes'])

        return {
            'available': len(available),
            'in_backoff': len(self.engines) - len(available),
            'total': len(self.engines),
            'total_successes': sum(self.success_count.values()),
            'engines': engines_list[:20]  # Top 20 engines
        }

    def load_state(self):
        """Load persisted backoff state from JSON file."""
        if not os.path.exists(self.state_file):
            return

        try:
            with open(self.state_file, 'r') as f:
                data = json.load(f)

            now = time.time()
            loaded_backoffs = 0

            # Restore failures
            if 'failures' in data:
                self.failures = data['failures']

            # Restore success counts
            if 'success_count' in data:
                self.success_count = data['success_count']

            # Restore backoff_until (only if still in future)
            if 'backoff_until' in data:
                for ident, until in data['backoff_until'].items():
                    if until > now:
                        self.backoff_until[ident] = until
                        loaded_backoffs += 1

            if loaded_backoffs > 0:
                _log('loaded %d active backoffs from state' % loaded_backoffs, 'info')

        except (IOError, ValueError) as e:
            _log('failed to load scraper state: %s' % str(e), 'warn')

    def save_state(self, force=False):
        """Save backoff state to JSON file.

        Args:
            force: If True, save immediately. Otherwise respect save interval.
        """
        now = time.time()
        if not force and (now - self._last_save) < self._save_interval:
            return

        try:
            # Ensure directory exists
            state_dir = os.path.dirname(self.state_file)
            if state_dir and not os.path.exists(state_dir):
                os.makedirs(state_dir)

            data = {
                'failures': self.failures,
                'backoff_until': self.backoff_until,
                'success_count': self.success_count,
                'saved_at': now
            }

            # Atomic write
            tmp_file = self.state_file + '.tmp'
            with open(tmp_file, 'w') as f:
                json.dump(data, f, indent=2)
            os.rename(tmp_file, self.state_file)
            self._last_save = now

        except (IOError, OSError) as e:
            _log('failed to save scraper state: %s' % str(e), 'warn')


engine_tracker = None


def get_scraper_stats():
    """Get scraper stats for API/dashboard."""
    if engine_tracker is None:
        return None
    return engine_tracker.get_stats()


def build_search_query(sqlite=None):
    """Build a search query using configured sources."""
    search = ''

    # Search by working proxy
    if 'p' in config.scraper.query:
        proxydb = mysqlite.mysqlite(config.watchd.database, str)
        proxies = [i[0] for i in proxydb.execute(
            'SELECT proxy FROM proxylist WHERE failed=0 ORDER BY RANDOM() LIMIT 10'
        ).fetchall()]
        if proxies and random.random() < 0.5:
            search = ' '.join(random.sample(proxies, random.randint(1, 2)))

    # Search by known website
    if ('w' in config.scraper.query and not search) or random.random() < 0.5:
        if sqlite is None:
            sqlite = mysqlite.mysqlite(config.ppf.database, str)
        uris = [i[0] for i in sqlite.execute(
            'SELECT url FROM uris WHERE error=0 AND url NOT LIKE "%github%" ORDER BY RANDOM() LIMIT 10'
        ).fetchall()]
        if uris and random.random() < 0.5:
            if search:
                search = '%s OR ' % search
            search = search + 'site:%s' % random.choice(uris).split('/')[2]

    # Search by term (multi-lingual)
    if ('s' in config.scraper.query and not search) or random.random() < 0.5:
        if search:
            search = '%s OR ' % search
        # 70% chance of non-English term
        if random.random() < 0.7:
            term = translations.get_random_search_term()
        else:
            term = random.choice(search_terms)
        search = search + term

    return search


def scrape_engine(engine, ident, query, urignore, sqlite):
    """Scrape a single engine for proxy list URLs."""
    max_pages = config.scraper.max_pages
    consecutive_empty = 0
    total_urls = 0

    for page in range(max_pages):
        try:
            url = engine.build_url(query, page)

            if config.scraper.debug:
                _log('%s page %d: %s' % (engine.name, page, url), 'debug')

            content = fetch.fetch_contents(url)

            # Check for rate limiting
            if engine.is_rate_limited(content):
                engine_tracker.mark_failure(ident)
                return total_urls

            if not content:
                consecutive_empty += 1
                if consecutive_empty >= config.scraper.fail_threshold:
                    engine_tracker.mark_failure(ident)
                    return total_urls
                continue

            # Extract URLs
            urls = engine.extract_urls(content, urignore)

            if not urls:
                # Empty results on first page likely means rate limited
                if page == 0:
                    engine_tracker.mark_failure(ident)
                return total_urls

            # Success
            engine_tracker.mark_success(ident)
            consecutive_empty = 0

            # Deduplicate and insert
            urls = list(set(urls))
            source = '%s (page %d, query: %s)' % (engine.name, page, query[:50])
            dbs.insert_urls(urls, source, sqlite)
            total_urls += len(urls)

            # Small delay between pages
            time.sleep(random.uniform(1.0, 3.0))

        except Exception as e:
            engine_tracker.mark_failure(ident)
            return total_urls

    return total_urls


def proxyfind(sqlite=None, urignore=None):
    """Find proxy list URLs using available search engines."""
    global engine_tracker

    # Get available engines
    available = engine_tracker.get_available()
    if not available:
        avail, backoff, total = engine_tracker.get_status()
        _log('all %d engines in backoff, sleeping 60s' % total, 'rate')
        time.sleep(60)
        return

    # Build search query
    query = build_search_query(sqlite)
    if not query:
        return

    if config.scraper.debug:
        _log('query: %s' % query, 'debug')

    # Shuffle and pick engines
    random.shuffle(available)

    # Use 1-3 engines per round
    num_engines = min(len(available), random.randint(1, 3))

    for engine, ident in available[:num_engines]:
        total = scrape_engine(engine, ident, query, urignore, sqlite)
        if total > 0:
            name = ident.split('/')[2] if '/' in ident else ident
            _log('%s: found %d URLs' % (name, total), 'scraper')

        # Delay between engines
        time.sleep(random.uniform(2.0, 5.0))


def load_urignore():
    """Load URL ignore patterns."""
    urignore = []

    # Load from file
    if os.path.exists('urignore.txt'):
        with open('urignore.txt', 'r') as f:
            urignore = [i.strip() for i in f.read().split('\n') if i.strip()]

    # Add Searx instances to ignore (avoid loops)
    for i in searx_instances:
        urignore.append(i.split('/')[2])

    # Add search engine domains to ignore
    ignore_domains = [
        'duckduckgo.com', 'startpage.com', 'mojeek.com', 'qwant.com',
        'yandex.com', 'yandex.ru', 'ecosia.org', 'brave.com',
        'google.com', 'bing.com', 'yahoo.com',
    ]
    for domain in ignore_domains:
        urignore.append(domain)

    return urignore


class Scraper(threading.Thread):
    """Background thread for search engine scraping."""

    def __init__(self, cfg):
        self.cfg = cfg
        self.running = False
        self.urignore = load_urignore()
        threading.Thread.__init__(self)
        self.daemon = True

    def init_tracker(self):
        """Initialize engine tracker with configured engines."""
        global engine_tracker
        enabled_engines = [e.strip() for e in self.cfg.scraper.engines.split(',')]
        engine_tracker = EngineTracker(
            enabled_engines,
            searx_instances,
            base_delay=self.cfg.scraper.backoff_base,
            max_delay=self.cfg.scraper.backoff_max
        )
        avail, backoff, total = engine_tracker.get_status()
        _log('scraper: %d engine(s) (%s)' % (total, ', '.join(enabled_engines)), 'info')

    def stop(self):
        """Signal the scraper to stop."""
        self.running = False

    def run(self):
        """Main scraper loop."""
        global config
        config = self.cfg
        fetch.set_config(self.cfg)
        translations.set_config(self.cfg)

        self.init_tracker()
        self.running = True

        # Create thread-local database connection
        urldb = mysqlite.mysqlite(self.cfg.ppf.database, str)

        while self.running:
            try:
                proxyfind(urldb, self.urignore)
                time.sleep(random.uniform(5.0, 15.0))
            except Exception as e:
                try:
                    err_msg = repr(e)
                    if isinstance(err_msg, unicode):
                        err_msg = err_msg.encode('ascii', 'backslashreplace')
                except:
                    err_msg = type(e).__name__
                _log('scraper error: %s' % err_msg, 'error')
                time.sleep(30)

        urldb.close()
        engine_tracker.save_state(force=True)
        avail, backoff, total = engine_tracker.get_status()
        _log('scraper stopped (%d/%d engines available)' % (avail, total), 'info')


if __name__ == '__main__':
    config.load()
    errors = config.validate()
    if errors:
        for e in errors:
            _log(e, 'error')
        import sys
        sys.exit(1)
    fetch.set_config(config)
    translations.set_config(config)

    proxydb = mysqlite.mysqlite(config.watchd.database, str)
    dbs.create_table_if_not_exists(proxydb, 'proxylist')

    urldb = mysqlite.mysqlite(config.ppf.database, str)
    dbs.create_table_if_not_exists(urldb, 'uris')

    # Load search terms from file if exists
    if os.path.exists('search_terms.txt'):
        with open('search_terms.txt', 'r') as f:
            terms = [i.strip() for i in f.read().split('\n') if i.strip()]
            if terms:
                search_terms = terms

    urignore = load_urignore()

    # Parse enabled engines from config
    enabled_engines = [e.strip() for e in config.scraper.engines.split(',')]

    # Initialize engine tracker
    engine_tracker = EngineTracker(
        enabled_engines,
        searx_instances,
        base_delay=config.scraper.backoff_base,
        max_delay=config.scraper.backoff_max
    )

    avail, backoff, total = engine_tracker.get_status()
    _log('loaded %d engine instances (%s)' % (total, ', '.join(enabled_engines)), 'info')

    try:
        while True:
            proxyfind(urldb, urignore)
            # Small delay between rounds
            time.sleep(random.uniform(5.0, 15.0))
    except KeyboardInterrupt:
        engine_tracker.save_state(force=True)
        avail, backoff, total = engine_tracker.get_status()
        _log('scraper stopped (engines: %d/%d available)' % (avail, total), 'info')