local MODNAME   = minetest.get_current_modname()
local WORLDPATH = minetest.get_worldpath()
local MODPATH   = minetest.get_modpath (MODNAME)
local TEXTDIR   = WORLDPATH .. "/wikitext"
local SNDDIR    = MODPATH   .. "/sounds"

strfile = {}

function strfile.open(s)
    return {
        _buf = s,
        _pos = 1,
        _readline = function(self)
            if self._pos == nil then
                return nil
            end
            local nl = self._buf:find("\n", self._pos, true)
            local line
            if nl then
                line = self._buf:sub(self._pos, nl - 1)
                nl = nl + 1
            else
                line = self._buf:sub(self._pos)
            end
            self._pos = nl
            return line
        end,
        lines = function(self)
            return self._readline, self, true
        end,
        close = function(self) end,
    }
end

wikilib.paths = {}
wikilib.paths.root    = TEXTDIR
wikilib.paths.pages   = TEXTDIR.."/pages"
wikilib.paths.plugins = TEXTDIR.."/plugins"
wikilib.paths.users   = TEXTDIR.."/users"

local WIKI_FORMNAME   = "wiki:wiki"

os.mkdir(TEXTDIR)
os.mkdir(wikilib.paths.pages)
os.mkdir(wikilib.paths.plugins)
os.mkdir(wikilib.paths.users)

local function name_to_filename(name)

    name = name:gsub("[^A-Za-z0-9-]", function(c)
        if c == " " then
            return "_"
        else
            return ("%%%02X"):format(c:byte(1))
        end
    end)
    return name:lower()

end

wikilib.name_to_filename = name_to_filename

-- ===================================================================

local function stopwiki (plname)
    if minetest.setting_getbool ("enable_damage") then
        local player = minetest.get_player_by_name (plname)
        if player then
            local hp = player:get_hp()
                minetest.log ("action",
"[wiki] hp for " .. plname .. "=" .. hp)
            if hp < 1 then
                minetest.log ("action",
"[wiki] disabled wiki for " .. plname .. " due to death")
                return true
            end
        end
    end

    return false
end

-- ===================================================================

local function get_page_path (name, player) --> path, is_file, allow_save
    local allow_save = minetest.check_player_privs (player, { wiki=true })
    local path

    if name:sub(1, 1) == "." then
        local text = wikilib.internal_pages[name] or wikilib.internal_pages[".NotFound_Internal"]
        if type(text) == "function" then
            text = text(player)
        end
        return text, false, false
    elseif name:sub(1, 1) == ":" then
        if name:match("^:[0-9]?$") then
            local n = tonumber(name:sub(2,2)) or 0
            path = "users/"..player.."/page"..n
            os.mkdir(wikilib.paths.users.."/"..player)
        elseif name == ":profile" then
            path = "users/"..player.."/profile"
            os.mkdir(wikilib.paths.users.."/"..player)
        elseif name:match("^:.-:[0-9]$") then
            local user, n = name:match("^:(.-):([0-9])$")
            if user:find("..[/\\]") then
                return wikilib.internal_pages[".BadPageName"], false, false
            end
            if (n == "0") and (not minetest.check_player_privs(player, {wiki_admin=true})) then
                return wikilib.internal_pages[".Forbidden"], false, false
            end
            path = "users/"..user.."/page"..n
            os.mkdir(TEXTDIR.."/users/"..user)
            allow_save = false
        elseif name:match("^:.-:profile$") then
            local user = name:match("^:(.-):.*$")
            if user:find("..[/\\]") then
                return wikilib.internal_pages[".BadPageName"], false, false
            end
            path = "users/"..user.."/profile"
            os.mkdir(TEXTDIR.."/users/"..user)
            allow_save = false
        else
            return wikilib.internal_pages[".BadPageName"], false, false
        end
    else
        path = "pages/"..name_to_filename(name)
    end

    return TEXTDIR.."/"..path, true, allow_save

end

local function find_links(lines) --> links
    local links = { }
    local links_n = 0
    for _,line in ipairs(lines) do
        for link in line:gmatch("%[(.-)%]") do
            links_n = links_n + 1
            links[links_n] = link
        end
    end
    return links
end

local function load_page (name, player) --> text, links, allow_save
    local text, allow_save = wikilib.plugin_handle_load(name, player)
    if text then
        return text, find_links(text:split("\n")), allow_save
    end
    local path, is_file, allow_save = get_page_path(name, player)
    local f
    if is_file then
        f = io.open(path)
        if not f then
            f = strfile.open(wikilib.internal_pages[".NotFound"])
        end
    else
        f = strfile.open(path)
    end
    local lines = { }
    local lines_n = 0
    for line in f:lines() do
        lines_n = lines_n + 1
        lines[lines_n] = line
    end
    f:close()
    local text = table.concat(lines, "\n")
    local links = find_links(lines)
    return text, links, allow_save
end

local function save_page (name, player, text)
    local ok = wikilib.plugin_handle_save(name, player, text)
    if ok then return ok end

    local path, is_file, allow_save = get_page_path(name, player)

    if (not is_file) or (not allow_save) then return end

    local f = io.open(path, "w")
    if not f then return end

    f:write(text)
    f:close()
end

local esc = minetest.formspec_escape

function wikilib.get_wiki_page_formspec (player, name, w, h)

    if name == "" then name = "Main" end
    w = w or 12
    h = h or 10

    local text, links, allow_save = load_page (name, player)
    local buttons = ""
    local bx = 0
    local by = 7.5
    local ii = 1
    local btype

    for i, link in ipairs(links) do
        if (ii > 5) then
            bx = 0
            by = by + 1.0
            ii = 1
        end

    if (link == "Close") or (link == "Quit") then
        btype = "button_exit"
    else
        btype = "button"
    end
        link = esc(link)
        buttons = buttons..((btype .. "[%f,%f;2.4,0.3;page_%s;%s]"):format(bx, by, link, link))
        bx = bx + 2.4
        ii = ii + 1
    end

    if (ii > 5) then
        bx = 0
        by = by + 1.0
        ii = 1
    end
    if allow_save then
        buttons = buttons..(("button[%f,%f;2.4,0.3;%s;%s]"):format(bx, by, "save", "Save"))
        bx = bx + 2.4
        ii = ii + 1
    end

    return ("size["..w..","..h.."]"
        .. "field[0,1;11,1;page;Page;"..esc(name).."]"
        .. "button[11,1;1,0.5;go;-]"
--      .. "bgcolor[#080808BB; false]"
        .. "bgcolor[#111188; false]"
        .. "textarea[0,2;12,6;text;"..esc(name)..";"..esc(text).."]"
        .. buttons
    )
end

function wikilib.show_wiki_page (plname, name)
    if stopwiki (plname) then return end

    if (name ~= "Close") and (name ~= "Quit") then
        local fs = wikilib.get_wiki_page_formspec (plname, name)
        minetest.show_formspec (plname, WIKI_FORMNAME, fs)
    end
end

minetest.register_node("wiki:wiki", {
    description = "Wiki",
    tiles = { "default_wood.png", "default_wood.png", "default_bookshelf.png" },
    groups = { choppy=3, oddly_breakable_by_hand=2, flammable=3 },
    sounds = default.node_sound_wood_defaults(),
    on_construct = function(pos)
        local meta = minetest.get_meta(pos)
        meta:set_string("infotext", "Wiki")
    end,
    on_rightclick = function(pos, node, clicker, itemstack)
        if clicker then
            wikilib.show_wiki_page (clicker:get_player_name(), "Main")
        end
    end,
})

minetest.register_privilege("wiki", {
    description = "Allow editing wiki pages in the global space",
    give_to_singleplayer = false,
})

minetest.register_privilege("wiki_admin", {
    description = "Allow editing wiki pages in any space",
    give_to_singleplayer = false,
})

local BS = "default:bookshelf"
local BSL = { BS, BS, BS }
-- minetest.register_craft({
--     output = "wiki:wiki",
--     recipe = { BSL, BSL, BSL },
-- })

function wikilib.handle_formspec(player, formname, fields)

    if (not formname) or (formname ~= WIKI_FORMNAME) then return end
    local plname = player:get_player_name()
    if fields.save then
        local r = save_page(fields.page, plname, fields.text)
        if type(r) == "string" then
            wikilib.show_wiki_page (plname, r)
        else
            wikilib.show_wiki_page (plname, fields.page)
        end
        return true
     elseif fields.go and minetest.check_player_privs(player:get_player_name(),{wiki_admin=true}) then
        wikilib.show_wiki_page (plname, fields.page)
        return true
     elseif fields.go and minetest.check_player_privs(player:get_player_name(),{wiki_admin=false}) then
        minetest.chat_send_player(plname, "This button is currently restricted, sorry for any inconvenience caused!")
        return true
    else
        for k in pairs(fields) do
            if type(k) == "string" then
                local name = k:match("^page_(.*)")
                if name then
                    wikilib.show_wiki_page (plname, name)
                    return true
                end
            end
        end
    end
end

minetest.register_on_player_receive_fields(function(player, formname, fields)
    wikilib.handle_formspec(player, formname, fields)
end)

-- ===================================================================

minetest.register_chatcommand ("english",{
    params = "",
    description="Information in English",
    func = function (name,params)
        wikilib.show_wiki_page (name, "info")
    end,
})

minetest.register_chatcommand ("info",{
    params = "",
    description="Information in English",
    func = function (name,params)
        wikilib.show_wiki_page (name, "info")
    end,
})

-- ===================================================================

minetest.register_chatcommand ("wiki",{
    params = "",
    description="Shows the wiki (same as /main)",
    func = function (name,params)
        wikilib.show_wiki_page (name, "Main")
    end,
})

minetest.register_chatcommand ("main",{
    params = "",
    description="Shows the wiki (same as /wiki)",
    func = function (name,params)
        wikilib.show_wiki_page (name, "Main")
    end,
})

if  ocutil.mod_missing ("newplayer") then
minetest.register_chatcommand ("rules",{
    params = "",
    description="Shows the wiki rules page",
    func = function (name,params)
        wikilib.show_wiki_page (name, "Rules")
    end,
})
end

minetest.register_chatcommand ("news",{
    params = "",
    description="Shows the news page",
    func = function (xx, params)
        wikilib.show_wiki_page (xx, "News")
    end,
})

-- ===================================================================

minetest.register_chatcommand ("francais",{
    params = "",
    description="Shows the French top page",
    func = function (xx, params)
        wikilib.show_wiki_page (xx, "French")
    end,
})

minetest.register_chatcommand ("france",{
    params = "",
    description="Shows the French top page",
    func = function (xx, params)
        wikilib.show_wiki_page (xx, "French")
    end,
})

minetest.register_chatcommand ("french",{
    params = "",
    description="Shows the French top page",
    func = function (xx, params)
        wikilib.show_wiki_page (xx, "French")
    end,
})

minetest.register_chatcommand ("commands",{
    params = "",
    description="Shows the /commands page",
    func = function (xx, params)
        wikilib.show_wiki_page (xx, "Commands")
    end,
})

-- ===================================================================

function ogg_exists (name)
    local f = io.open (SNDDIR .. "/" .. name .. ".ogg", "r")
    if f ~= nil then io.close (f) return true else return false end
end

function wikilib.quack_quack (plname, pos, name)

    if stopwiki (plname) then return end

    if ogg_exists (plname) then
        minetest.sound_play (plname,
            { pos=pos, gain = 2.0, max_hear_distance = 5000 })
    end

    if (name ~= "Close") and (name ~= "Quit") then
        local fs = wikilib.get_wiki_page_formspec (plname, name)
        minetest.show_formspec (plname, WIKI_FORMNAME, fs)
    end
end

minetest.register_on_joinplayer(function (player)
    local name = player:get_player_name()
    if player:get_hp() <= 0 then return end

    if  ocutil.mod_missing ("newplayer") or
        minetest.check_player_privs (name, { interact=true }) then

        minetest.log ("action",
            "showing wiki to " .. name)

        minetest.after (2, wikilib.quack_quack,
           player:get_player_name(),
           player:getpos(),
           "main")
    else
        minetest.log ("action",
            "disabled wiki for " .. name .. " due to initial checks")
    end
end)