local BASEPATH = wikilib.paths.plugins.."/ml"

os.mkdir(BASEPATH)

local ML_DB_FILE = BASEPATH.."/posts.dat"

local posts = { }

local function load_posts()
    local f = io.open(ML_DB_FILE, "r")
    if not f then return false end
    local list = { }
    local post = { text="" }
    for line in f:lines() do
        if line:len() == 0 then
            if post.who and post.date then
                table.insert(list, post)
                post = { text="" }
            end
        elseif line:sub(1, 5) == "From:" then
            post.who = line:sub(6):trim()
        elseif line:sub(1, 5) == "Date:" then
            post.date = line:sub(6):trim()
        else
            post.text = post.text..line.."\n"
        end
    end
    if post.who and post.date then
        table.insert(list, post)
        post = { text="" }
    end
    f:close()
    posts = list
    return true
end

local function save_posts()
    local f = io.open(ML_DB_FILE, "w")
    if not f then return false end
    for _, post in ipairs(posts) do
        f:write("From: "..post.who.."\n")
        f:write("Date: "..post.date.."\n")
        for _, line in ipairs(post.text:split("\n")) do
            if line:len() == 0 then
                f:write(" \n")
            elseif (line:sub(1, 5) == "From:")
                or (line:sub(1, 5) == "Date:") then
                f:write(" "..line.."\n")
            else
                f:write(line.."\n")
            end
        end
        f:write("\n")
    end
    f:close()
    return true
end

local player_states = { }

local BACKLOG = 5

local function get_player_state(name)
    if not player_states[name] then
        player_states[name] = { }
    end
    return player_states[name]
end

local SEP = ("-"):rep(64)

wikilib.register_plugin({
    regex = "^/ml/.*",
    description = "Mailing List [/ml/recent]",
    load_page = function(entry, player) --> text, allow_save
        local state = get_player_state(player)
        local what = entry:match("^/ml/(.*)")
        if not what then
            what = "recent"
        end
        what = what:lower()
        if what == "recent" then
            local text = "Recent Posts:\n\n"..SEP.."\n"
            for i = #posts - BACKLOG, #posts do
                local p = posts[i]
                if p then
                    local nl = ((p.text:sub(-1) == "\n") and "" or "\n")
                    text = (text
                        .. "[/ml/"..i.."] \n"
                        .. "From: "..p.who.."\n"
                        .. "Date: "..p.date.."\n"
                        .. p.text..nl
                        .. SEP.."\n"
                    )
                end
            end
            text = text.."\n  * [/ml/Post] a new message"
            text = text.."\n  * Back to [Main]"
            return text, false
        elseif what:match("[0-9]+") then
            local n = tonumber(what)
            local text
            if posts[n] then
                local nl = ((posts[n].text:sub(-1) == "\n") and "" or "\n")
                text = ("Post #"..n.."\n"
                    .. "From: "..posts[n].who.." [:"..posts[n].who..":profile]\n"
                    .. "Date: "..posts[n].date.."\n"
                    .. posts[n].text..nl
                    .. "\n"
                )
            else
                text = "No such post.\n\n"
            end
            text = text.."\n  * [/ml/Post] a new message"
            text = text.."\n  * View [/ml/Recent] messages"
            text = text.."\n  * Back to [Main]"
            return text, false
        elseif what == "post" then
            return "Subject:\n\n<Edit this message and save to post>", true
        end
        return "Wrong request.", false
    end,
    save_page = function(entry, player, text) --> bool
        local state = get_player_state(player)
        local what = entry:match("^/ml/(.*)")
        if not what then
            what = "post"
        end
        what = what:lower()
        if what == "post" then
            posts[#posts + 1] = {
                who = player,
                date = os.date("%Y-%m-%d %H:%M:%S"),
                text = text,
            }
            save_posts()
            return "/ml/recent"
        end
        return true
    end,
})


load_posts()