-- lib/log.lua — Structured logging for CC:Tweaked programs
-- Usage:
--   local log = dofile("lib/log.lua")
--   log.info("SMELT", "Loaded %d recipes", count)
--   log.warn("NET",   "No modem found")
--   log.setLevel("DEBUG")   -- show everything
--
-- Levels: DEBUG < INFO < WARN < ERROR
-- Default level: INFO (suppresses DEBUG)

local LEVELS = { DEBUG = 1, INFO = 2, WARN = 3, ERROR = 4 }
local minLevel = LEVELS.INFO

local log = {}

--- Set minimum log level (string: "DEBUG", "INFO", "WARN", "ERROR")
function log.setLevel(level)
    minLevel = LEVELS[level] or LEVELS.INFO
end

--- Get the current minimum level name
function log.getLevel()
    for name, val in pairs(LEVELS) do
        if val == minLevel then return name end
    end
    return "INFO"
end

local function emit(levelName, tag, msg, ...)
    if LEVELS[levelName] < minLevel then return end
    local text
    if select("#", ...) > 0 then
        text = string.format(msg, ...)
    else
        text = msg
    end
    print(string.format("[%s][%s] %s", levelName, tag, text))
end

function log.debug(tag, msg, ...) emit("DEBUG", tag, msg, ...) end
function log.info(tag, msg, ...)  emit("INFO",  tag, msg, ...) end
function log.warn(tag, msg, ...)  emit("WARN",  tag, msg, ...) end
function log.error(tag, msg, ...) emit("ERROR", tag, msg, ...) end

return log