--[[-- Command Module - Help
Game command to list and search all registered commands in a nice format
@commands _system-ipc

@usage-- Get all messages related to banning a player
/commands ban
-- Get the second page of results
/commands ban 2
]]

local Global = require("modules/exp_util/global")
local Commands = require("modules/exp_commands")

local PAGE_SIZE = 5

local search_cache = {}
Global.register(search_cache, function(tbl)
    search_cache = tbl
end)

--- Format commands into a strings across multiple pages
local function format_as_pages(commands, page_size)
    local pages = { {} }
    local page_length = 0
    local current_page = 1
    local total = 0

    for _, command in pairs(commands) do
        total = total + 1
        page_length = page_length + 1
        if page_length > page_size then
            current_page = current_page + 1
            pages[current_page] = {}
            page_length = 1
        end

        local aliases = #command.aliases > 0 and {"exp-commands-help.aliases", table.concat(command.aliases, ", ")} or ""
        pages[current_page][page_length] = { "exp-commands-help.format", command.name, command.description, command.help, aliases }
    end

    return pages, total
end

Commands.new("commands", "List and search all commands for a keyword")
:add_aliases{ "chelp", "helpp" }
:argument("keyword", "string")
:optional("page", "integer")
:defaults{ page = 1 }
:register(function(player, keyword, page)
    keyword = keyword:lower()
    local pages, found
    local cache = search_cache[player.index]
    if cache and cache.keyword == keyword then
        -- Cached value found, no search is needed
        pages = cache.pages
        found = cache.found
    else
        -- No cached value, so a search needs to be done
        local commands = Commands.search_for_player(keyword, player)
        pages, found = format_as_pages(commands, PAGE_SIZE)
        search_cache[player.index] = { keyword = keyword, pages = pages, found = found }
    end

	-- Error if no pages found
	if found == 0 then
		return Commands.status.success{ "exp-commands-help.no-results" }
	end

    local page_data = pages[page]
    if page_data == nil then
        -- Page number was out of range for this search
        return Commands.status.invalid_input{"exp-commands-help.out-of-range", page, #pages }
    end

    -- Print selected page to the player
    Commands.print{ "exp-commands-help.header", keyword == '' and '<all>' or keyword }
    for _, command in pairs(page_data) do
        Commands.print(command)
    end
    return Commands.status.success{ "exp-commands-help.footer", found, page, #pages }
end)