local lootCmd = "char loot";

-- Maximum loot shown on use of the loot command.
local MAX_LOOT_VALUE = 20;
-- Maximum results the loot table may contain, default: 500.
-- NOTE: This is the lua table, so everything will be stored as normal.
local MAX_RESULTS = 500;

-- Player events.
local PLAYER_EVENT_ON_USE_COMMAND = 42;
local PLAYER_EVENT_ON_LOOT_ITEM = 32;

-- Userdata types.
local USERDATA_TYPE_PLAYER = 4;

-- Pre-set queries.
local QUERY_SELECT_DEFAULT = 1;
local QUERY_SELECT_SPECIFIC = 2;
local QUERY_INSERT_DEFAULT = 3;
local QUERY_SELECT_COUNT = 4;
local query = {
    [[
        SELECT date_time, player, item_id, item_count
        FROM player_loots
        WHERE player = '%s';
    ]],
    [[
        SELECT date_time, player, item_id, item_count
        FROM player_loots
        WHERE player = '%s' AND item_id = '%d';
    ]],
    [[
        INSERT INTO player_loots
        VALUES ('%d', '%s', '%d', '%d', '%d', '0');
    ]],
    [[
        SELECT count(*)
        FROM player_loots
    ]],
    __call = function (tab, n, ...)
        return CharDBQuery(tab[n]:format(...));
    end
};
setmetatable(query, query);
-- We need the length of the player_loots table.
local tableLength = query(QUERY_SELECT_COUNT):GetUInt32(0)+1;

-- Function to convert the time from the
-- database to an actual date.
local function getDate(date_time)
    return os.date("%x [%X]", date_time);
end

-- Table that will hold the loot information.
local mtLoot = {
    -- Function that will keep the table clean,
    -- we don't want to many entries ...
    __newindex = function (tab, key, value)
        if #tab >= MAX_RESULTS then
            collectgarbage();
        end
        rawset(tab, key, value);
    end,
    -- Weak table so collectgarbage() can do its job.
    __mode = 'kv',
    -- Should we notify that we are cleaning the table?
    __gc = function() print"Wiping the loot table." end,
    __len = function (t)
        local length = 0;
        for _, tab in pairs(t) do
            length = length + #tab;
        end
        return length;
    end
};
local lootTable = setmetatable({}, mtLoot);
local function prepareResult(result)
    -- If the result is nil, we should return it
    -- right away to prevent errors.
    if result == nil then  return {}; end
    -- Result isn't nil so we can process the results.
    local lootTable = {};
    for i=1, result:GetRowCount() do
        lootTable[i] = {
            getDate(result:GetUInt32(0)),       -- date_time
            result:GetString(1),                -- player
            GetItemLink(result:GetUInt32(2)),   -- item_id
            result:GetUInt8(3)                  -- item_count
        };
        -- No point in loading data we won't use ...
        if #lootTable == MAX_LOOT_VALUE then
            break;
        end
        result:NextRow();
    end
    return lootTable;
end
-- Function to properly load the result. We will check if the result
-- exists already first, if not, then and only then we will run a query
-- to get the results we need.
local function loadResult(player, item)
    local key = player .. (item or "");
    local result = lootTable[key];
    if type(result) ~= "table" then
        -- Which query shall we use?
        local q;
        if type(item) == "number" then
            q = QUERY_SELECT_SPECIFIC;
        else -- No item so default select query.
            q = QUERY_SELECT_DEFAULT;
        end
        -- Grabbing and assigning the result.
        result = prepareResult(query(q, player, item));
        lootTable[key] = result;
    end
    return result;
end

local function getLoot(target, item, ...)
    local result;
    if tonumber(item) then
        result = loadResult(target, tonumber(item));
    elseif select(1, ...) then
        return {}; -- If there are arguments in ... then we have to many arguments.
    else -- No extra arguments ...
        result = loadResult(target);
    end
    return type(result) == "table" and result or {};
end
-- Function that will handle the command.
local lootMsg = "%s: %s has looted item: %s, count: %d";
local function handleLootCommand(plr, msg)
    local arguments = {};
    if msg:find(lootCmd .. " ") == 1 then
        -- Grabbing the words and processing them.
        msg:gsub(lootCmd .. " ", ""):gsub("(%w+)", function (w) table.insert(arguments, w) end);
    end
    -- We want to run this if there aren't any extra arguments but also
    -- if the only argument is an item id.
    if msg:find(lootCmd .. " ") ~= 1 or #arguments == 1 and tonumber(arguments[1]) then
        local target = plr:GetSelection();
        -- Making sure we have a target, and that target
        -- is a player .. creatures don't loot >.>.
        if type(target) ~= "userdata" then
            return plr:SendAreaTriggerMessage("No target selected.");
        elseif target:GetTypeId() ~= USERDATA_TYPE_PLAYER then
            return plr:SendAreaTriggerMessage("Invalid target selected, expecting a player.");
        end
        table.insert(arguments, 1, target:GetName());
    end
    -- Search for loot, if any..., and send the information
    -- to the requester.
    local loot = getLoot(table.unpack(arguments));
    if next(loot) == nil then
        return plr:SendAreaTriggerMessage("No results found.");
    end
    for index, value in ipairs(loot) do
        plr:SendBroadcastMessage(lootMsg:format(table.unpack(value)));
        -- Letting the requester know there is more loot, we
        -- just won't show it.
        if index == MAX_LOOT_VALUE then
            plr:SendBroadcastMessage(("More than %d results found, aborting."):format(MAX_LOOT_VALUE));
        end
    end
    return false;
end
-- A separate function to handle the command,
-- so we only have to use 'return false' once.
local function onLootCommand(_, plr, msg)
    if msg:find(lootCmd) == 1 then
        if plr:GetGMRank() > 0 then
            handleLootCommand(plr, msg);
        end
        return false;
    end
    -- We don't want any message displaying now,
    -- do we?
end

-- Function to catch every item that is looted
-- and put the information in the database.
local function registerPlayerLoot(_, plr, item, count)
    local date_time = os.time();
    local player = plr:GetName();
    local entry = item:GetEntry();
    -- Gotta add it to the existing table aswell.
    if lootTable[player] ~= nil then
        table.insert(lootTable[player], {getDate(date_time), player, GetItemLink(entry), count});
    end
    if lootTable[player .. entry] ~= nil then
        table.insert(lootTable[player .. entry], {getDate(date_time), player, GetItemLink(entry), count});
    end
    -- Insert the data into the database and incrementing tableLength
    -- by one so it stays valid.
    query(QUERY_INSERT_DEFAULT, tableLength, player, date_time, entry, count);
    tableLength = tableLength + 1;
end

RegisterPlayerEvent(PLAYER_EVENT_ON_USE_COMMAND, onLootCommand);
RegisterPlayerEvent(PLAYER_EVENT_ON_LOOT_ITEM, registerPlayerLoot);