LibMobs.lua

local MAJOR, MINOR = "LibMobs", 10101
assert(LibStub, MAJOR .. " requires LibStub")

local lib = LibStub:NewLibrary(MAJOR, MINOR)
if not lib then return end

-- Blizzard
local UnitGUID = _G.UnitGUID
local issecretvalue = _G.issecretvalue or function() return false end -- Retail only

-- Mine
function lib:print(...)
    print("|cffffa1a1" .. MAJOR .. ":|r", ...)
end

lib.units = lib.units or {}

-- https://warcraft.wiki.gg/wiki/GUID#Creature
--[[ Method: lib:ParseGUID(guid)
## Parameters
* guid - unit GUID return from UnitGUID, e.g: "Creature-0-1465-0-2105-448-000043F59F"

## Returns
* info              - the components of GUID
    * unitType      - the type of the entity. (string)
    * serverID      - the ID of the server (realm) where the entity was created. (number)
    * instanceID    - the ID of the instance where the entity exists. (number)
    * zoneUID       - the ID of the zone or map where the entity is located. (number)
    * npcID         - the entry ID of the NPC in the game database. (number)
    * spawnUID      - a unique identifier for the specific instance or spawn of this NPC. Differentiates between multiple spawns of the same NPC type. (string)
]]
function lib:ParseCreatureGUID(guid)
    if not guid or issecretvalue(guid) then
        return nil
    end

    local unitType, _, serverID, instanceID, zoneUID, npcID, spawnUID = string.split("-", guid)

    -- validate the number of parts
    if not unitType or not serverID or not instanceID or not zoneUID or not npcID or not spawnUID then
        return nil -- invalid GUID type
    end

    -- check for valid entity types
    if unitType ~= "Creature" and unitType ~= "Vehicle" and unitType ~= "Pet" then
        return nil -- unsupported type
    end

    -- return the parsed GUID components
    return {
        guid = guid,
        unitType = unitType,
        serverID = tonumber(serverID),
        instanceID = tonumber(instanceID),
        zoneUID = tonumber(zoneUID),
        npcID = tonumber(npcID),
        spawnUID = spawnUID
    }
end

--[[ Method: lib:GetNPCID(guid)
## Parameters
* unit - the unit for which you want to capture the npcID.

## Returns
* npcID - the entry ID of the NPC in the game database. (number)
]]
function lib:GetNPCID(unit)
    local guid = UnitGUID(unit)
    local info = self:ParseCreatureGUID(guid)
    if not info then
        return nil
    end
    return info.npcID
end

function lib:GetInstanceMobs(instanceID)
    return lib.units[instanceID or "none"]
end

function lib:GetCreature(instanceID, npcID)
    local data = self:GetInstanceMobs(instanceID)
    if data then
        return data[npcID or "none"]
    end
    return nil
end

function lib:UnitRole(unit)
    local guid = UnitGUID(unit)
    if not issecretvalue(guid) and guid then
        local guidInfo = self:ParseCreatureGUID(guid)
        if guidInfo then
            local mobInfo = self:GetCreature(guidInfo.instanceID, guidInfo.npcID)
            if mobInfo then
                return mobInfo.role
            end
        end
    end
    return nil
end