#!/usr/bin/python3

import os
import re
import shlex
import sys
import time

import config
import db

repo_path = config.get('serve', 'repo-path')
repo_regex = config.get('serve', 'repo-regex')
git_shell_cmd = config.get('serve', 'git-shell-cmd')
git_update_cmd = config.get('serve', 'git-update-cmd')
ssh_cmdline = config.get('serve', 'ssh-cmdline')

enable_maintenance = config.getboolean('options', 'enable-maintenance')
maintenance_exc = config.get('options', 'maintenance-exceptions').split()


def pkgbase_from_name(pkgbase):
    conn = db.Connection()
    cur = conn.execute("SELECT ID FROM PackageBases WHERE Name = ?", [pkgbase])

    row = cur.fetchone()
    return row[0] if row else None


def pkgbase_exists(pkgbase):
    return pkgbase_from_name(pkgbase) is not None


def list_repos(user):
    conn = db.Connection()

    cur = conn.execute("SELECT ID FROM Users WHERE Username = ?", [user])
    userid = cur.fetchone()[0]
    if userid == 0:
        die('{:s}: unknown user: {:s}'.format(action, user))

    cur = conn.execute("SELECT Name, PackagerUID FROM PackageBases " +
                       "WHERE MaintainerUID = ?", [userid])
    for row in cur:
        print((' ' if row[1] else '*') + row[0])
    conn.close()


def create_pkgbase(pkgbase, user):
    if not re.match(repo_regex, pkgbase):
        die('{:s}: invalid repository name: {:s}'.format(action, pkgbase))
    if pkgbase_exists(pkgbase):
        die('{:s}: package base already exists: {:s}'.format(action, pkgbase))

    conn = db.Connection()

    cur = conn.execute("SELECT ID FROM Users WHERE Username = ?", [user])
    userid = cur.fetchone()[0]
    if userid == 0:
        die('{:s}: unknown user: {:s}'.format(action, user))

    now = int(time.time())
    cur = conn.execute("INSERT INTO PackageBases (Name, SubmittedTS, " +
                       "ModifiedTS, SubmitterUID, MaintainerUID) VALUES " +
                       "(?, ?, ?, ?, ?)", [pkgbase, now, now, userid, userid])
    pkgbase_id = cur.lastrowid

    cur = conn.execute("INSERT INTO PackageNotifications " +
                       "(PackageBaseID, UserID) VALUES (?, ?)",
                       [pkgbase_id, userid])

    conn.commit()
    conn.close()


def pkgbase_set_keywords(pkgbase, keywords):
    pkgbase_id = pkgbase_from_name(pkgbase)
    if not pkgbase_id:
        die('{:s}: package base not found: {:s}'.format(action, pkgbase))

    conn = db.Connection()

    conn.execute("DELETE FROM PackageKeywords WHERE PackageBaseID = ?",
                 [pkgbase_id])
    for keyword in keywords:
        conn.execute("INSERT INTO PackageKeywords (PackageBaseID, Keyword) " +
                     "VALUES (?, ?)", [pkgbase_id, keyword])

    conn.commit()
    conn.close()


def pkgbase_has_write_access(pkgbase, user):
    conn = db.Connection()

    cur = conn.execute("SELECT COUNT(*) FROM PackageBases " +
                       "LEFT JOIN PackageComaintainers " +
                       "ON PackageComaintainers.PackageBaseID = PackageBases.ID " +
                       "INNER JOIN Users " +
                       "ON Users.ID = PackageBases.MaintainerUID " +
                       "OR PackageBases.MaintainerUID IS NULL " +
                       "OR Users.ID = PackageComaintainers.UsersID " +
                       "WHERE Name = ? AND Username = ?", [pkgbase, user])
    return cur.fetchone()[0] > 0


def die(msg):
    sys.stderr.write("{:s}\n".format(msg))
    exit(1)


def die_with_help(msg):
    die(msg + "\nTry `{:s} help` for a list of commands.".format(ssh_cmdline))


def warn(msg):
    sys.stderr.write("warning: {:s}\n".format(msg))


def usage(cmds):
    sys.stderr.write("Commands:\n")
    colwidth = max([len(cmd) for cmd in cmds.keys()]) + 4
    for key in sorted(cmds):
        sys.stderr.write("  " + key.ljust(colwidth) + cmds[key] + "\n")
    exit(0)


user = os.environ.get('AUR_USER')
privileged = (os.environ.get('AUR_PRIVILEGED', '0') == '1')
ssh_cmd = os.environ.get('SSH_ORIGINAL_COMMAND')
ssh_client = os.environ.get('SSH_CLIENT')

if not ssh_cmd:
    die_with_help("Interactive shell is disabled.")
cmdargv = shlex.split(ssh_cmd)
action = cmdargv[0]
remote_addr = ssh_client.split(' ')[0] if ssh_client else None

if enable_maintenance:
    if remote_addr not in maintenance_exc:
        die("The AUR is down due to maintenance. We will be back soon.")

if action == 'git-upload-pack' or action == 'git-receive-pack':
    if len(cmdargv) < 2:
        die_with_help("{:s}: missing path".format(action))

    path = cmdargv[1].rstrip('/')
    if not path.startswith('/'):
        path = '/' + path
    if not path.endswith('.git'):
        path = path + '.git'
    pkgbase = path[1:-4]
    if not re.match(repo_regex, pkgbase):
        die('{:s}: invalid repository name: {:s}'.format(action, pkgbase))

    if action == 'git-receive-pack' and pkgbase_exists(pkgbase):
        if not privileged and not pkgbase_has_write_access(pkgbase, user):
            die('{:s}: permission denied: {:s}'.format(action, user))

    os.environ["AUR_USER"] = user
    os.environ["AUR_PKGBASE"] = pkgbase
    os.environ["GIT_NAMESPACE"] = pkgbase
    cmd = action + " '" + repo_path + "'"
    os.execl(git_shell_cmd, git_shell_cmd, '-c', cmd)
elif action == 'set-keywords':
    if len(cmdargv) < 2:
        die_with_help("{:s}: missing repository name".format(action))
    pkgbase_set_keywords(cmdargv[1], cmdargv[2:])
elif action == 'list-repos':
    if len(cmdargv) > 1:
        die_with_help("{:s}: too many arguments".format(action))
    list_repos(user)
elif action == 'setup-repo':
    if len(cmdargv) < 2:
        die_with_help("{:s}: missing repository name".format(action))
    if len(cmdargv) > 2:
        die_with_help("{:s}: too many arguments".format(action))
    warn('{:s} is deprecated. Use `git push` to create new repositories.'.format(action))
    create_pkgbase(cmdargv[1], user)
elif action == 'restore':
    if len(cmdargv) < 2:
        die_with_help("{:s}: missing repository name".format(action))
    if len(cmdargv) > 2:
        die_with_help("{:s}: too many arguments".format(action))

    pkgbase = cmdargv[1]
    if not re.match(repo_regex, pkgbase):
        die('{:s}: invalid repository name: {:s}'.format(action, pkgbase))

    if pkgbase_exists(pkgbase):
        die('{:s}: package base exists: {:s}'.format(action, pkgbase))
    create_pkgbase(pkgbase, user)

    os.environ["AUR_USER"] = user
    os.environ["AUR_PKGBASE"] = pkgbase
    os.execl(git_update_cmd, git_update_cmd, 'restore')
elif action == 'help':
    cmds = {
        "help": "Show this help message and exit.",
        "list-repos": "List all your repositories.",
        "restore <name>": "Restore a deleted package base.",
        "set-keywords <name> [...]": "Change package base keywords.",
        "setup-repo <name>": "Create a repository (deprecated).",
        "git-receive-pack": "Internal command used with Git.",
        "git-upload-pack": "Internal command used with Git.",
    }
    usage(cmds)
else:
    die_with_help("invalid command: {:s}".format(action))