-- load pfUI environment
setfenv(1, pfUI:GetEnvironment())

--[[ libunitscan ]]--
-- A pfUI library that detects and saves all kind of unit related informations.
-- Such as level, class, elite-state and playertype. Each query causes the library
-- to automatically scan for the target if not already existing. Player-data is
-- persisted within the pfUI_playerDB where the mob data is a throw-away table.
-- The automatic target scanner is only working for vanilla due to client limitations
-- on further expansions.
--
-- External functions:
--   GetUnitInfo(name, active, isPlayer)
--     Returns information of the given unitname. Returns nil if no match is found.
--     When nothing is found and the active flag is set, the autoscanner will
--     automatically pick it up and try to fill the missing entry by targetting the unit.
--     Pass isPlayer=true/false to restrict the lookup to the players or mobs table
--     (avoids name-collision false positives, e.g. a player and an NPC named Chromie).
--
--     class[String] - The class of the unit
--     level[Number] - The level of the unit
--     elite[String] - The elite state of the unit (See UnitClassification())
--     player[Boolean] - Returns true if unit is a player
--     guild[String] - Returns guild name of unit is a player
--
-- Internal functions:
--   libunitscan:AddData(db, name, class, level, elite)
--     Adds unit data to a given db. Where db should be either "players" or "mobs"
--

-- return instantly when another libunitscan is already active
if pfUI.api.libunitscan then return end

local units = { players = {}, mobs = {} }
local queue = { }

-- Feed (guid, name, classToken) into ClassicAPI's persistent name
-- cache when the unit's GUID is resolvable. Roster-style packets
-- (party / raid / inspect on glance) carry class inline, so the
-- engine often doesn't issue a separate name query and the DLL's
-- NameCache hook never fires for them — this is where we close that gap.
local function RememberByUnit(unit, name, class)
  if not (name and class) then return end
  local guid = UnitGUID(unit)
  if not guid then return end
  C_PlayerCache.RememberPlayer(guid, name, class, UnitRace(unit), UnitSex(unit))
end

function GetUnitInfo(name, active, isPlayer)
  if isPlayer ~= false and units["players"][name] then
    local ret = units["players"][name]
    return ret.class, ret.level, ret.elite, true, ret.guild
  elseif isPlayer ~= true and units["mobs"][name] then
    local ret = units["mobs"][name]
    return ret.class, ret.level, ret.elite, nil, ret.guild
  elseif active then
    queue[name] = true
    libunitscan:Show()
  end
end

local function AddData(db, name, class, level, elite, guild)
  if not name or not db then return end
  units[db] = units[db] or {}
  units[db][name] = units[db][name] or {}
  units[db][name].class = class or units[db][name].class
  units[db][name].level = level or units[db][name].level
  units[db][name].elite = elite or units[db][name].elite
  units[db][name].guild = guild or units[db][name].guild
  queue[name] = nil
end

local libunitscan = CreateFrame("Frame", "pfUnitScan", UIParent)
libunitscan:RegisterEvent("PLAYER_ENTERING_WORLD")
libunitscan:RegisterEvent("FRIENDLIST_UPDATE")
libunitscan:RegisterEvent("GUILD_ROSTER_UPDATE")
libunitscan:RegisterEvent("RAID_ROSTER_UPDATE")
libunitscan:RegisterEvent("PARTY_MEMBERS_CHANGED")
libunitscan:RegisterEvent("PLAYER_TARGET_CHANGED")
libunitscan:RegisterEvent("WHO_LIST_UPDATE")
libunitscan:RegisterEvent("CHAT_MSG_SYSTEM")
libunitscan:RegisterEvent("UPDATE_MOUSEOVER_UNIT")
libunitscan:RegisterEvent("NAME_PLATE_UNIT_ADDED")
libunitscan:SetScript("OnEvent", function()
  if event == "PLAYER_ENTERING_WORLD" then

    -- load pfUI_playerDB
    units.players = pfUI_playerDB

    -- update own character details
    local name = UnitName("player")
    local class = UnitClassBase("player")
    local level = UnitLevel("player")
    local guild = GetGuildInfo("player")
    AddData("players", name, class, level, nil, guild)
    RememberByUnit("player", name, class)

  elseif event == "FRIENDLIST_UPDATE" then
    for i = 1, GetNumFriends() do
      local info = C_FriendList.GetFriendInfoByIndex(i)
      if info then
        local level = info.level > 0 and info.level or nil
        AddData("players", info.name, info.classFilename, level)
      end
    end

  elseif event == "GUILD_ROSTER_UPDATE" then
    local name, class, level, _, guild
    for i = 1, GetNumGuildMembers() do
      name, _, _, level, class = GetGuildRosterInfo(i)
      guild = GetGuildInfo("player")
      class = L["class"][class] or nil
      AddData("players", name, class, level, nil, guild)
    end

  elseif event == "RAID_ROSTER_UPDATE" then
    local name, class, SubGroup, level, unit, _
    for i = 1, GetNumRaidMembers() do
      unit = "raid" .. i
      name, _, SubGroup, level, class = GetRaidRosterInfo(i)
      class = L["class"][class] or nil
      AddData("players", name, class, level)
      RememberByUnit(unit, name, class)
    end

  elseif event == "PARTY_MEMBERS_CHANGED" then
    local name, class, level, unit, _, guild
    for i = 1, GetNumPartyMembers() do
      unit = "party" .. i
      class = UnitClassBase(unit)
      name = UnitName(unit)
      level = UnitLevel(unit)
      guild = GetGuildInfo(unit)
      AddData("players", name, class, level, nil, guild)
      RememberByUnit(unit, name, class)
    end

  elseif event == "WHO_LIST_UPDATE" or event == "CHAT_MSG_SYSTEM" then
    for i = 1, C_FriendList.GetNumWhoResults() do
      local info = C_FriendList.GetWhoInfo(i)
      if info then
        AddData("players", info.fullName, info.filename, info.level, nil, info.fullGuildName)
      end
    end

  elseif event == "UPDATE_MOUSEOVER_UNIT" or event == "PLAYER_TARGET_CHANGED" or event == "NAME_PLATE_UNIT_ADDED" then
    local scan = event == "PLAYER_TARGET_CHANGED" and "target"
              or event == "NAME_PLATE_UNIT_ADDED" and arg1
              or "mouseover"
    local name, class, level, elite, guild, _
    if UnitExists(scan) then
      if UnitIsPlayer(scan) then
        class = UnitClassBase(scan)
        level = UnitLevel(scan)
        -- UnitLevel returns -1 for unknown levels, don't overwrite known values
        level = level > 0 and level or nil
        name = UnitName(scan)
        guild = GetGuildInfo(scan)
        AddData("players", name, class, level, nil, guild)
        RememberByUnit(scan, name, class)
      else
        class = UnitClassBase(scan)
        elite = UnitClassification(scan)
        level = UnitLevel(scan)
        -- UnitLevel returns -1 for unknown levels, don't overwrite known values
        level = level > 0 and level or nil
        name = UnitName(scan)
        guild = UnitSubName(scan)
        AddData("mobs", name, class, level, elite, guild)
      end
    end
  end
end)

-- setup sound function switches
local SoundOn = PlaySound
local SoundOff = function() return end

libunitscan:SetScript("OnUpdate", function()
  -- don't scan when another unit is in target
  if UnitExists("target") or UnitName("target") then return end

  local name = next(queue)
  if name then
    -- disable sound
    _G.PlaySound = SoundOff

    -- try to target the unknown unit
    TargetByName(name, true)
    ClearTarget()

    -- enable sound again
    _G.PlaySound = SoundOn

    queue[name] = nil
  end

  this:Hide()
end)

pfUI.api.libunitscan = libunitscan