Architecture — ResistForever

ResistForever — technical architecture and probability semantics

Installed module and lifecycle

ResistForever.toc / Interface 16001 / Version 1.0.2
  -> ResistForever.lua
       | five resistance-school atlas identifiers
       | pure direct-spell average/bucket and base-miss functions
       | protected numeric/string reads + session cache
       | context resolution: player/pet defender, target attacker level
       | PaperDollStatTooltip post-hook: append lines
       | StatFrame row Init post-hook: tag school and refresh
       | event-driven cache/open-tooltip refresh

No external library, SavedVariables, network messaging, persistent logs, slash commands or independently packaged test harness is present. .pkgmeta points to CHANGELOG.md as a manual changelog for release packaging metadata.

School and hover-row identity

Five schools map to enum Enum.Damageclass where readable, otherwise fallback IDs Fire=2, Nature=3, Frost=4, Shadow=5, Arcane=6. Each is associated with UI-Character-Info-Resistance-[School] atlas, which tags stat-row frames through CharacterStatFrameScrollBoxIconElementMixin.Init.

ResolveTooltipUnit checks frame.unit for player or pet; otherwise it walks ancestry under CharacterStatsPaneScrollBox or CharacterStatsPanePetScrollBox. Only recognized resistance rows within those panes trigger the tooltip extension, reducing the chance of attaching to unrelated stat types.

hooksecurefunc adds a post-hook to Blizzard's PaperDollStatTooltip and the stat-element Init, preserving existing tooltip content. The addon requires GameTooltip:IsOwned(frame), guards against its own append recursion, tracks the current openRow, and uses PaperDollStatTooltip(row) again to refresh after relevant unit events. GameTooltip OnHide clears the row reference.

Protected value acquisition and cache

Forever may return numbers or strings with secret/protected access restrictions. IsSecret uses optional issecretvalue and canaccessvalue guarded by pcall. UsableNumber excludes non-numbers, inaccessible values and NaN before arithmetic; WholeLevel enforces positive levels and rounds to nearest integer.

ResolveResistance prioritizes:

The currently displayed frame's numericValue, if readable.
Direct UnitResistance(unit, school): the third (effective) return if accessible, otherwise the second (real) return.
Last-known session cache for that unit and school.

The paper-doll UI may internally show a different realResistance value to ExpectedSpellResistance; using the readable row's value avoids assuming the historical UI helper equals the newer server-side formula. ResolveUnitLevel similarly asks UnitLevel(unit) then checks last-known level.

The cache structure is cache.level[player/pet] and cache.resistance[player/pet][schoolID]. RefreshResistanceCache updates it during subscribed events. If resistance or level is reused from cache, the rendered tooltip appends “Using last available resistance value”. The cache does not persist across sessions. Potential ambiguity: pet unit tokens can refer to different pets over time; there is no explicit identity-aware purge if a newly summoned pet's values are still inaccessible.

Pure mathematical model

Let defender readable resistance be R and hypothetical attacker level L.

Average direct spell fraction resisted:

a = R / (R + 9L) for R > 0, L ≥ 1. Unknown/nonpositive R produces no partial-resist buckets. It is not the previous 0.75 × R/(5L) UI helper.

Discrete reduction distribution on step outcomes x=0.0,0.1,...1.0:

For a ≤ 0.10, P(0) = 1 - 7.5a, P(0.1) = 5a, P(0.2) = 2.5a; other buckets zero.
For a ≥ 0.90, let q=1-a; P(1) = 1-7.5q, P(0.9)=5q, P(0.8)=2.5q; other buckets zero.
Otherwise, for each 10% step, P(x) = max(0, 0.5 - 2.5 * abs(x-a)).

The code instantiates all eleven buckets but lists 10–100% only. It skips values below PROBABILITY_EPSILON=0.0005 (fraction) or that format as 0.0%. Thus a user cannot recover the complete probability mass merely by adding visible rows; the 0% resisted chance is deliberately hidden.

Base spell miss:

Let d = defenderLevel - attackerLevel. For d ≥ 3: 0.17. Otherwise: max(0, 0.04 + 0.01d). This is base miss before attacker spell hit, distinct from partial resistance and not an inevitable miss floor. Level differences -4 or smaller yield 0%.

BuildResistanceContext constructs miss independently from buckets, so missing/zero R may still show base miss. It returns nil bucket distribution if mean cannot be calculated. Rounded row values display one decimal.

Model scope: direct magical spell hits. Comments explicitly state periodic non-channeled ticks appear to use a different (roughly one-tenth average) model; channels/binary spells also differ. Spell penetration and attacker spell-hit bonuses aren't accessible from a hovered character-sheet resistance row, so this display cannot produce exact odds for every individual attack.

Contexts displayed to the player

AppendResistanceTooltip reads the hovered defender's resistance/level and constructs a same-level context with attackerLevel=defenderLevel. It optionally reads the currently selected target's level from UnitLevel("target"), provided the unit exists, is not the player, has a positive valid level and differs from the defender's level. A valid name appears in the target section label.

A negative/sentinel/skull target level does not become an invented +3 level. No target comparison is shown for invalid or equal level. The target's resistance is not involved.

If neither context generates visible meaningful rows, no additional section is appended. Otherwise the existing tooltip is followed by a blank, Resist Forever title, and one or two context subsections with double-line percentage rows. Base spell miss and partial probabilities are labeled independently.

Hooks, events and exposure

The addon creates a frame subscribed to ADDON_LOADED, PLAYER_LOGIN, PLAYER_ENTERING_WORLD, PLAYER_EQUIPMENT_CHANGED, PLAYER_LEVEL_UP, PLAYER_TARGET_CHANGED, PLAYER_REGEN_ENABLED, UNIT_PET. It also registers UNIT_AURA, UNIT_RESISTANCES and UNIT_LEVEL for player/pet through RegisterUnitEvent if supported, otherwise global RegisterEvent versions filtered when the unit argument is present.

Every relevant event retries hook installation, refreshes readable player/pet cache values and, apart from ADDON_LOADED, attempts to regenerate the currently open resistance tooltip. The post-hook row Init similarly refreshes if that same row is currently open. No periodic OnUpdate loop or timer is defined in this Lua source.

hooksInstalled prevents multiple secure hook registrations; appending prevents recursive calls while the addon is drawing its own rows. Unknown accessibility or UI implementation changes can still affect results and should be tested on the actual client.

Packaging and test status

Only ResistForever.lua and ResistForever.toc are required at runtime. GitHub releases v1.0.1/v1.0.2 exist without attached ZIP artifacts. LICENSE grants MIT terms and .pkgmeta names the manual changelog. No tests/ path exists in the current tree. Static inspection confirms design, not mathematical calibration against combat logs or successful UI behavior in-game.

Document information

Inspected: ResistForever.lua (583 lines including terminal line), ResistForever.toc, .pkgmeta, Git versions 1.0.0–1.0.2; October 27, 2026. Static source review only.

ResistForever: Architecture