#!/usr/bin/python
import subprocess
import os
import sys
import shutil
import errno
import json
import ujson
import platform
import re
import traceback

sys.path.insert(0, os.path.join(os.path.dirname(__file__), "../api"))
import zulip

lock_path = "/var/tmp/log2zulip.lock"
control_path = "/etc/log2zulip.conf"

def mkdir_p(path):
    # Python doesn't have an analog to `mkdir -p` < Python 3.2.
    try:
        os.makedirs(path)
    except OSError, e:
        if e.errno == errno.EEXIST and os.path.isdir(path):
            pass
        else:
            raise

def send_log_zulip(file_name, count, lines, extra=""):
    content = "%s new errors%s:\n```\n%s\n```" % (count, extra, "\n".join(lines))
    zulip_client.send_message({
        "type": "stream",
        "to": "logs",
        "subject": "%s on %s" % (file_name, platform.node()),
        "content": content,
        })

def process_lines(raw_lines, file_name):
    lines = []
    for line in raw_lines:
        # Add any filtering or modification code here
        if re.match(".*upstream timed out.*while reading upstream.*", line):
            continue
        lines.append(line)

    if len(lines) == 0:
        return
    elif len(lines) > 10:
        send_log_zulip(file_name, len(lines), lines[0:3], extra=", examples include")
    else:
        send_log_zulip(file_name, len(lines), lines)

def process_logs():
    for filename in log_files:
        data_file_path = "/var/tmp/log2zulip.state"
    mkdir_p(os.path.dirname(data_file_path))
    if not os.path.exists(data_file_path):
        file(data_file_path, "w").write("{}")
    last_data = ujson.loads(file(data_file_path).read())
    new_data = {}
    for log_file in log_files:
        file_data = last_data.get(log_file, {})
        if not os.path.exists(log_file):
            # If the file doesn't exist, log an error and then move on to the next file
            print "Log file %s does not exist!" % (log_file,)
            continue
        length = int(subprocess.check_output(["wc", "-l", log_file]).split()[0])
        if file_data.get("last") is None:
            file_data["last"] = 1
        if length + 1 < file_data["last"]:
            # The log file was rotated, restart from empty.  Note that
            # because we don't actually store the log file content, if
            # a log file ends up at the same line length as before
            # immediately after rotation, this tool won't notice.
            file_data["last"] = 1
        new_lines = subprocess.check_output(["tail", "-n+%s" % (file_data["last"],), log_file]).split('\n')[:-1]
        if len(new_lines) > 0:
            process_lines(new_lines, filename)
            file_data["last"] += len(new_lines)
        new_data[log_file] = file_data
    file(data_file_path, "w").write(ujson.dumps(new_data))

if __name__ == "__main__":
    if os.path.exists(lock_path):
        print "Log2zulip lock held; not doing anything"
        sys.exit(0)

    try:
        file(lock_path, "w").write("1")
        zulip_client = zulip.Client(config_file="/etc/log2zulip.zuliprc")
        try:
            log_files = ujson.loads(file(control_path, "r").read())
        except Exception:
            print "Could not load control data from %s" % (control_path,)
            traceback.print_exc()
            sys.exit(1)
        process_logs()
    finally:
        try:
            os.remove(lock_path)
        except OSError, IOError:
            pass