--
-- Helper functions
--

-- match all lines and output them as-is
local function logwatch_filter_all (name)
    return { name=name }
end

-- match using a regex pattern, but output the full line
local function logwatch_filter_raw (name, pat)
    return { name=name, pat=pat }
end

-- match using a regexp pattern, and output a formatted line
local function logwatch_filter (name, pat, fmt)
    return { name=name, pat=pat, fmt=fmt }
end

-- match using a regexp pattern, and do *not* output
local function logwatch_filter_blackhole (name, pat)
    return { name=name, pat=pat, channel_is_null=true }
end

logwatch_timestamp_pat = "\\w{3} [0-9 ]\\d \\d{2}:\\d{2}:\\d{2}"

-- match auth.log sudo entries
local function logwatch_filter_sudo (name)
    return logwatch_filter(name,
        "^" .. logwatch_timestamp_pat .. " (?P<hostname>\\S+)\\s+sudo:\\s*(?P<username>\\S+) : TTY=(?P<tty>\\S+) ; PWD=(?P<pwd>.+?) ; USER=(?P<target_user>\\S+) ; COMMAND=(?P<command>.*)$",
        "{username}:{tty} - {target_user}@{hostname}:{pwd} - {command:r}"
    )
end

-- filter out the prefixed timestamp from lines
local function logwatch_filter_strip_timestamp (name)
    return logwatch_filter(name,
        "^" .. logwatch_timestamp_pat .. " (?P<line>.+)$",
        "{line}"
    )
end

-- filter out auth.log cron messages
local function logwatch_filter_no_cron (name)
    return logwatch_filter_blackhole(name,
        "^" .. logwatch_timestamp_pat .. " \\S+\\s+(CRON|su)\\[\\d+\\]: pam_unix\\(\\w+:\\w+\\): session (opened|closed) for user \\w+( by \\(uid=\\d+\\))?$"
    )
end

-- filter out auth.log 'su for nobody by root' messages
local function logwatch_filter_no_su_nobody (name)
    return logwatch_filter_blackhole(name,
        "^" .. logwatch_timestamp_pat .. " \\S+\\s+su\\[\\d+\\]: (Successful su for nobody by root|\\+ \\?\\?\\? root:nobody)$"
    )
end

--
-- Procedural config
--
local function apply_config (conf)
    -- apply general
    log_level(conf.log_level)

    -- apply conf.name
    client:set_defaults(conf.name.nickname, conf.name.username, conf.name.realname)

    -- apply conf.networks
    for network, settings in pairs(conf.networks) do
        -- establish the irc_net
        net = client:connect(network, settings.hostname)

        -- join each channel
        for i, channel in ipairs(settings.channels) do
            net:join(channel)
        end
    end

    -- apply conf.modules_path
    if conf.modules_path then
        modules:path(conf.modules_path)
    end

    -- apply conf.modules
    for name, settings in pairs(conf.modules) do
        -- load the module
        module = modules:load(name, settings.path)

        -- apply confs
        for key, value in pairs(settings.conf) do
            module:conf(key, value)
        end
    end

    -- conf.mod_logwatch
    if conf.mod_logwatch then
        module = modules:load("logwatch")

        for fifo_path, settings in pairs(conf.mod_logwatch) do
            module:conf("source_fifo", fifo_path)
            source_name = fifo_path
            
            for i, filter in ipairs(settings.filters) do
                if filter.channel_is_null then
                    channel = nil
                else
                    channel = settings.channel
                end

                module:conf("filter", filter.name, source_name, filter.pat, filter.fmt, channel)
            end
        end
    end
end

--
-- Declarative configuration settings
--
apply_config{
    log_level   = "DEBUG",

    name = {
        nickname    = "SpBotDev",
        username    = "spbot-dev",
        realname    = "SpBot (development version)"
    },

    networks = {
        PVLNet      = {
            hostname    = "irc.fixme.fi",

            channels    = {
                "#test"
            }
        },
    },

    modules_path    = "src/modules",

    modules = {
        irc_log     = {
            conf        = {
                db_info     = "dbname=spbot",
                channel     = "PVLNet/#test",
            }
        }
    },

    mod_logwatch = {
        ["test.fifo"] = {
            channel     = "PVLNet/#test",
            
            filters     = {
                logwatch_filter_raw             ("test.foo", "foo"  ),
                logwatch_filter_sudo            ("test.sudo"        ),
                logwatch_filter_no_cron         ("test.no_cron"     ),
                logwatch_filter_no_su_nobody    ("test.no_cron_su"  ),
                logwatch_filter_strip_timestamp ("test.all"         )
            }
        },
    },
}