#!/usr/bin/env python3

import traceback
import os
from sys import exit, stdout
from os.path import join as pathjoin
from os.path import getsize
from common.cgi import parse_qs, parse_auth, start_response
from common.datadb import get_latest_backup


def handle_head(backup_name):
    try:
        # backup_path = get_latest_backup(backup_name)
        # TODO appropriate content-length for HEAD
        start_response(extra_headers=['Content-length: 0'])
    except:
        start_response(status_code=("404", "Not Found",), extra_headers=['Content-length: 0'])
    exit(0)


def handle_get_rsync(backup_name):
    """
    Prints the absolute path an rsync backup should pull from
    """
    backup_path = get_latest_backup(backup_name)

    start_response()
    print(backup_path + '/')


def handle_get_archive(backup_name):
    """
    Returns .tar.gz data to the browser
    """
    backup_path = pathjoin(get_latest_backup(backup_name), 'backup.tar.gz')

    with open(backup_path, 'rb') as f:
        start_response(content_type="application/x-gzip",
                       extra_headers=["Content-length: %s" % getsize(backup_path),
                                      "Content-Disposition: attachment; filename=\"backup.tar.gz\""])
        while True:
            data = f.read(8192)
            if not data:
                break
            stdout.buffer.write(data)
    exit(0)


def handle_req():
    """
    Parse http query parameters and act accordingly.
    """
    params = parse_qs()

    for param_name in ["proto", "name"]:
        if param_name not in params:
            raise Exception("Missing parameter: %s" % param_name)

    if os.environ['REQUEST_METHOD'] == "GET" and params["proto"] == "rsync":
        # Should return absolute local path to latest backup dir
        handle_get_rsync(params["name"])

    elif os.environ['REQUEST_METHOD'] == "GET" and params["proto"] == "archive":
        # Should respond by transferring tar.gz data
        handle_get_archive(params["name"])

    elif os.environ['REQUEST_METHOD'] == "HEAD":
        # Respond with 200 or 404 depending if backup exists
        # TODO: deeper inspection so the headers can be flushed out
        handle_head(params["name"])

    else:
        raise Exception("Invalid request. Params: %s" % params)


if __name__ == "__main__":
    try:
        handle_req()
    except Exception as e:
        start_response(status_code=("500", "Internal server error"))

        tb = traceback.format_exc()
        print(tb)