enum NPCFlags
{
    UNIT_NPC_FLAG_NONE                  = 0x00000000,
    UNIT_NPC_FLAG_GOSSIP                = 0x00000001,       // 100%
    UNIT_NPC_FLAG_QUESTGIVER            = 0x00000002,       // guessed, probably ok
    UNIT_NPC_FLAG_UNK1                  = 0x00000004,
    UNIT_NPC_FLAG_UNK2                  = 0x00000008,
    UNIT_NPC_FLAG_TRAINER               = 0x00000010,       // 100%
    UNIT_NPC_FLAG_TRAINER_CLASS         = 0x00000020,       // 100%
    UNIT_NPC_FLAG_TRAINER_PROFESSION    = 0x00000040,       // 100%
    UNIT_NPC_FLAG_VENDOR                = 0x00000080,       // 100%
    UNIT_NPC_FLAG_VENDOR_AMMO           = 0x00000100,       // 100%, general goods vendor
    UNIT_NPC_FLAG_VENDOR_FOOD           = 0x00000200,       // 100%
    UNIT_NPC_FLAG_VENDOR_POISON         = 0x00000400,       // guessed
    UNIT_NPC_FLAG_VENDOR_REAGENT        = 0x00000800,       // 100%
    UNIT_NPC_FLAG_REPAIR                = 0x00001000,       // 100%
    UNIT_NPC_FLAG_FLIGHTMASTER          = 0x00002000,       // 100%
    UNIT_NPC_FLAG_SPIRITHEALER          = 0x00004000,       // guessed
    UNIT_NPC_FLAG_SPIRITGUIDE           = 0x00008000,       // guessed
    UNIT_NPC_FLAG_INNKEEPER             = 0x00010000,       // 100%
    UNIT_NPC_FLAG_BANKER                = 0x00020000,       // 100%
    UNIT_NPC_FLAG_PETITIONER            = 0x00040000,       // 100% 0xC0000 = guild petitions, 0x40000 = arena team petitions
    UNIT_NPC_FLAG_TABARDDESIGNER        = 0x00080000,       // 100%
    UNIT_NPC_FLAG_BATTLEMASTER          = 0x00100000,       // 100%
    UNIT_NPC_FLAG_AUCTIONEER            = 0x00200000,       // 100%
    UNIT_NPC_FLAG_STABLEMASTER          = 0x00400000,       // 100%
    UNIT_NPC_FLAG_GUILD_BANKER          = 0x00800000,       // cause client to send 997 opcode
    UNIT_NPC_FLAG_UNK3                  = 0x01000000,       // cause client to send 1015 opcode