local M = {}

-- Helper functions

function M.format_time(time)
    local seconds = time
    local days = math.floor(seconds / 86400)
    local hours = math.floor(seconds % 86400 / 3600)
    local minutes = math.floor(seconds % 3600 / 60)
    local result = ""

    if days > 0 then
        result = result .. days .. "d "
    end

    if hours > 0 then
        result = result .. hours .. "h "
    end

    if minutes > 0 then
        result = result .. minutes .. "m"
    end

    return result
end

-- Capture the first line of an invoked system process
-- (discards of error messages of the last command (the
-- one after the last pipe ('|')))
function M.process_get_one_line(proc)
    local pipe = io.popen(proc .. " 2>/dev/null", "r")
    if not pipe then return nil end

    local data = pipe:read("*l")
    pipe:close()
    return data
end

-- Get the lenght of the longest info name (for padding)
function M.longest_info_name_length(modules)
    local longest = 0

    for _, mod in ipairs(modules) do
        if type(mod.name) == "string" and #mod.name > longest then
            longest = #mod.name
        end
    end

    return longest
end

--[[
-- Loop through a file and for each line perform
-- a callback function, if it returns true, the
-- loop can end prematurely (this is wanted)
--]]
function M.for_line_in_file(filename, callback)
    local file = io.open(filename, "r")
    if not file then return nil end

    for line in file:lines() do
        if callback(line) then
            file:close()
            return true
        end
    end

    file:close()
    return false
end

-- filter a file line-by-line and return the given match
function M.grep(filename, regex)
    local capture

    M.for_line_in_file(filename, function(line)
        capture = line:match(regex)

        return capture ~= nil
    end)

    return capture
end

-- Returns the contents of the first line in a file
function M.cat_first_line(filename)
    local file = io.open(filename, "r")
    if not file then return nil end

    local line = file:read("*l")
    file:close()
    return line
end

return M