local totals = {}
local last = 0
local incomplete = false

local function on_combat(batch)
    local friendly = {}
    local self = l2.units.self()
    if self then friendly[self.id] = true end
    for _, member in ipairs(l2.units.party()) do friendly[member.id] = true end
    if batch.overflow then incomplete = true end
    for _, event in ipairs(batch.records) do
        local source = event.owner > 0 and event.owner or event.source
        if friendly[source] and (event.kind == "damage" or event.kind == "heal") then
            if last > 0 and event.server_ms - last > 12000 then
                totals, incomplete = {}, batch.overflow
            end
            last = math.max(last, event.server_ms)
            local row = totals[source] or { damage = 0, healing = 0 }
            if event.kind == "damage" then row.damage = row.damage + event.hp + event.cp
            else row.healing = row.healing + event.hp + event.cp end
            totals[source] = row
        end
    end
end

local function draw()
    if not l2.has("combat") then
        l2.ui.panel("meter", "Combat meter", "Waiting for a compatible L2G combat feed.")
        return
    end

    local names = {}
    local player = l2.units.self()
    if player then names[player.id] = player.name end
    for _, member in ipairs(l2.units.party()) do names[member.id] = member.name end
    local rows = {}
    for id, row in pairs(totals) do
        if names[id] then rows[#rows + 1] = { name = names[id], damage = row.damage, healing = row.healing } end
    end
    table.sort(rows, function(a, b) return a.damage > b.damage end)
    local lines = { "Damage  /  Healing" }
    for i = 1, math.min(6, #rows) do
        local row = rows[i]
        lines[#lines + 1] = string.format("%s  %d  /  %d", row.name, math.floor(row.damage), math.floor(row.healing))
    end
    if #rows == 0 then lines[#lines + 1] = "Waiting for combat." end
    if incomplete then lines[#lines + 1] = "Some combat events were dropped." end
    l2.ui.panel("meter", "Combat meter", table.concat(lines, "\n"))
end

function main()
    l2.on("combat.batch", on_combat)
    l2.on("party.changed", function() totals, last, incomplete = {}, 0, false end)
    l2.on("tick", draw)
end