package main

import "math"

// od.go computes the Mag-Tools "OD" (over-damage vs best retail) rating for
// melee/missile/wand weapons, ported from UtilityBelt's
// Lib/ItemInfoHelper/{WeaponMods,MiscCalcs,Dictionaries}.cs and
// Tools/ItemInfo.cs (CalcMeleeDamage / CalcMissileDamage / the OD display
// lines ~631-647). See docs/superpowers/specs/2026-07-15-weapon-od-rating-design.md.

// bestKey mirrors the (Skill, Mastery, MultiStrike, WieldReq) DataTable.Select
// key UB uses for an EXACT match lookup — no nearest-tier rounding.
type bestKey struct {
	skill       int
	mastery     int
	multiStrike int
	wieldReq    int
}

// bestValue mirrors the trailing DataTable columns:
// (MaxDmg, MaxVar, MaxDmgMod, MaxElementalDmgBonus, MaxElementalDmgVsMonsters).
type bestValue struct {
	maxDmg       float64
	maxVar       float64
	maxDmgMod    float64
	maxElemBonus float64
	maxElemVsMon float64
}

// bestValues is transcribed row-for-row from
// UtilityBelt/UtilityBelt/Lib/ItemInfoHelper/WeaponMods.cs BestValuesDatatable.GetTable().
// Column order in the source Rows.Add is:
// (Skill, Mastery, MultiStrike, WieldReq, MaxDmg, MaxVar, MaxDmgMod, MaxElementalDmgBonus, MaxElementalDmgVsMonsters)
// — omitted trailing columns default to 0. 301 rows total (matches
// `grep -c "table.Rows.Add" WeaponMods.cs`).
var bestValues = map[bestKey]bestValue{
	// heavyweaponry (skill 44) http://acpedia.org/wiki/Heavy_Weaponry
	// axe
	{44, 3, 0, 0}:   {26, .90, 0, 0, 0},
	{44, 3, 0, 250}: {33, .90, 0, 0, 0},
	{44, 3, 0, 300}: {40, .90, 0, 0, 0},
	{44, 3, 0, 325}: {47, .90, 0, 0, 0},
	{44, 3, 0, 350}: {54, .90, 0, 0, 0},
	{44, 3, 0, 370}: {61, .90, 0, 0, 0},
	{44, 3, 0, 400}: {69, .90, 0, 0, 0},
	{44, 3, 0, 420}: {71, .90, 0, 0, 0},
	{44, 3, 0, 430}: {74, .90, 0, 0, 0},
	// dagger
	{44, 6, 0, 0}:   {24, .47, 0, 0, 0},
	{44, 6, 0, 250}: {31, .47, 0, 0, 0},
	{44, 6, 0, 300}: {38, .47, 0, 0, 0},
	{44, 6, 0, 325}: {45, .47, 0, 0, 0},
	{44, 6, 0, 350}: {51, .47, 0, 0, 0},
	{44, 6, 0, 370}: {58, .47, 0, 0, 0},
	{44, 6, 0, 400}: {65, .47, 0, 0, 0},
	{44, 6, 0, 420}: {68, .47, 0, 0, 0},
	{44, 6, 0, 430}: {71, .47, 0, 0, 0},
	// msdagger
	{44, 6, 1, 0}:   {13, .40, 0, 0, 0},
	{44, 6, 1, 250}: {16, .40, 0, 0, 0},
	{44, 6, 1, 300}: {20, .40, 0, 0, 0},
	{44, 6, 1, 325}: {23, .40, 0, 0, 0},
	{44, 6, 1, 350}: {26, .40, 0, 0, 0},
	{44, 6, 1, 370}: {30, .40, 0, 0, 0},
	{44, 6, 1, 400}: {33, .40, 0, 0, 0},
	{44, 6, 1, 420}: {36, .40, 0, 0, 0},
	{44, 6, 1, 430}: {38, .40, 0, 0, 0},
	// mace
	{44, 4, 0, 0}:   {22, .30, 0, 0, 0},
	{44, 4, 0, 250}: {29, .30, 0, 0, 0},
	{44, 4, 0, 300}: {36, .30, 0, 0, 0},
	{44, 4, 0, 325}: {43, .30, 0, 0, 0},
	{44, 4, 0, 350}: {49, .30, 0, 0, 0},
	{44, 4, 0, 370}: {56, .30, 0, 0, 0},
	{44, 4, 0, 400}: {63, .30, 0, 0, 0},
	{44, 4, 0, 420}: {66, .30, 0, 0, 0},
	{44, 4, 0, 430}: {69, .30, 0, 0, 0},
	// spear
	{44, 5, 0, 0}:   {25, .59, 0, 0, 0},
	{44, 5, 0, 250}: {32, .59, 0, 0, 0},
	{44, 5, 0, 300}: {39, .59, 0, 0, 0},
	{44, 5, 0, 325}: {46, .59, 0, 0, 0},
	{44, 5, 0, 350}: {58, .59, 0, 0, 0},
	{44, 5, 0, 370}: {59, .59, 0, 0, 0},
	{44, 5, 0, 400}: {66, .59, 0, 0, 0},
	{44, 5, 0, 420}: {69, .59, 0, 0, 0},
	{44, 5, 0, 430}: {72, .59, 0, 0, 0},
	// sword
	{44, 2, 0, 0}:   {24, .47, 0, 0, 0},
	{44, 2, 0, 250}: {31, .47, 0, 0, 0},
	{44, 2, 0, 300}: {38, .47, 0, 0, 0},
	{44, 2, 0, 325}: {45, .47, 0, 0, 0},
	{44, 2, 0, 350}: {51, .47, 0, 0, 0},
	{44, 2, 0, 370}: {58, .47, 0, 0, 0},
	{44, 2, 0, 400}: {65, .47, 0, 0, 0},
	{44, 2, 0, 420}: {68, .47, 0, 0, 0},
	{44, 2, 0, 430}: {71, .47, 0, 0, 0},
	// mssword
	{44, 2, 1, 0}:   {13, .40, 0, 0, 0},
	{44, 2, 1, 250}: {16, .40, 0, 0, 0},
	{44, 2, 1, 300}: {20, .40, 0, 0, 0},
	{44, 2, 1, 325}: {23, .40, 0, 0, 0},
	{44, 2, 1, 350}: {26, .40, 0, 0, 0},
	{44, 2, 1, 370}: {30, .40, 0, 0, 0},
	{44, 2, 1, 400}: {33, .40, 0, 0, 0},
	{44, 2, 1, 420}: {36, .40, 0, 0, 0},
	{44, 2, 1, 430}: {38, .40, 0, 0, 0},
	// staff
	{44, 7, 0, 0}:   {23, .38, 0, 0, 0},
	{44, 7, 0, 250}: {30, .38, 0, 0, 0},
	{44, 7, 0, 300}: {36, .38, 0, 0, 0},
	{44, 7, 0, 325}: {43, .38, 0, 0, 0},
	{44, 7, 0, 350}: {50, .38, 0, 0, 0},
	{44, 7, 0, 370}: {56, .38, 0, 0, 0},
	{44, 7, 0, 400}: {63, .38, 0, 0, 0},
	{44, 7, 0, 420}: {66, .38, 0, 0, 0},
	{44, 7, 0, 430}: {70, .38, 0, 0, 0},
	// ua
	{44, 1, 0, 0}:   {20, .44, 0, 0, 0},
	{44, 1, 0, 250}: {26, .44, 0, 0, 0},
	{44, 1, 0, 300}: {31, .44, 0, 0, 0},
	{44, 1, 0, 325}: {37, .44, 0, 0, 0},
	{44, 1, 0, 350}: {43, .44, 0, 0, 0},
	{44, 1, 0, 370}: {48, .44, 0, 0, 0},
	{44, 1, 0, 400}: {54, .44, 0, 0, 0},
	{44, 1, 0, 420}: {56, .44, 0, 0, 0},
	{44, 1, 0, 430}: {59, .44, 0, 0, 0},

	// light weaponry (skill 45) http://acpedia.org/wiki/Light_Weaponry
	// axe
	{45, 3, 0, 0}:   {22, .80, 0, 0, 0},
	{45, 3, 0, 250}: {28, .80, 0, 0, 0},
	{45, 3, 0, 300}: {33, .80, 0, 0, 0},
	{45, 3, 0, 325}: {39, .80, 0, 0, 0},
	{45, 3, 0, 350}: {44, .80, 0, 0, 0},
	{45, 3, 0, 370}: {50, .80, 0, 0, 0},
	{45, 3, 0, 400}: {55, .80, 0, 0, 0},
	{45, 3, 0, 420}: {57, .80, 0, 0, 0},
	{45, 3, 0, 430}: {61, .80, 0, 0, 0},
	// dagger
	{45, 6, 0, 0}:   {18, .42, 0, 0, 0},
	{45, 6, 0, 250}: {24, .42, 0, 0, 0},
	{45, 6, 0, 300}: {29, .42, 0, 0, 0},
	{45, 6, 0, 325}: {35, .42, 0, 0, 0},
	{45, 6, 0, 350}: {40, .42, 0, 0, 0},
	{45, 6, 0, 370}: {46, .42, 0, 0, 0},
	{45, 6, 0, 400}: {51, .42, 0, 0, 0},
	{45, 6, 0, 420}: {54, .42, 0, 0, 0},
	{45, 6, 0, 430}: {58, .42, 0, 0, 0},
	// msdagger
	{45, 6, 1, 0}:   {7, .24, 0, 0, 0},
	{45, 6, 1, 250}: {11, .24, 0, 0, 0},
	{45, 6, 1, 300}: {13, .24, 0, 0, 0},
	{45, 6, 1, 325}: {16, .24, 0, 0, 0},
	{45, 6, 1, 350}: {18, .24, 0, 0, 0},
	{45, 6, 1, 370}: {21, .24, 0, 0, 0},
	{45, 6, 1, 400}: {24, .24, 0, 0, 0},
	{45, 6, 1, 420}: {27, .24, 0, 0, 0},
	{45, 6, 1, 430}: {28, .24, 0, 0, 0},
	// mace
	{45, 4, 0, 0}:   {19, .23, 0, 0, 0},
	{45, 4, 0, 250}: {24, .23, 0, 0, 0},
	{45, 4, 0, 300}: {29, .23, 0, 0, 0},
	{45, 4, 0, 325}: {35, .23, 0, 0, 0},
	{45, 4, 0, 350}: {40, .23, 0, 0, 0},
	{45, 4, 0, 370}: {45, .23, 0, 0, 0},
	{45, 4, 0, 400}: {50, .23, 0, 0, 0},
	{45, 4, 0, 420}: {53, .23, 0, 0, 0},
	{45, 4, 0, 430}: {57, .23, 0, 0, 0},
	// spear
	{45, 5, 0, 0}:   {21, .65, 0, 0, 0},
	{45, 5, 0, 250}: {26, .65, 0, 0, 0},
	{45, 5, 0, 300}: {32, .65, 0, 0, 0},
	{45, 5, 0, 325}: {37, .65, 0, 0, 0},
	{45, 5, 0, 350}: {42, .65, 0, 0, 0},
	{45, 5, 0, 370}: {48, .65, 0, 0, 0},
	{45, 5, 0, 400}: {53, .65, 0, 0, 0},
	{45, 5, 0, 420}: {57, .65, 0, 0, 0},
	{45, 5, 0, 430}: {60, .65, 0, 0, 0},
	// sword
	{45, 2, 0, 0}:   {20, .42, 0, 0, 0},
	{45, 2, 0, 250}: {25, .42, 0, 0, 0},
	{45, 2, 0, 300}: {31, .42, 0, 0, 0},
	{45, 2, 0, 325}: {36, .42, 0, 0, 0},
	{45, 2, 0, 350}: {41, .42, 0, 0, 0},
	{45, 2, 0, 370}: {47, .42, 0, 0, 0},
	{45, 2, 0, 400}: {52, .42, 0, 0, 0},
	{45, 2, 0, 420}: {55, .42, 0, 0, 0},
	{45, 2, 0, 430}: {58, .42, 0, 0, 0},
	// mssword
	{45, 2, 1, 0}:   {7, .24, 0, 0, 0},
	{45, 2, 1, 250}: {10, .24, 0, 0, 0},
	{45, 2, 1, 300}: {13, .24, 0, 0, 0},
	{45, 2, 1, 325}: {16, .24, 0, 0, 0},
	{45, 2, 1, 350}: {18, .24, 0, 0, 0},
	{45, 2, 1, 370}: {21, .24, 0, 0, 0},
	{45, 2, 1, 400}: {24, .24, 0, 0, 0},
	{45, 2, 1, 420}: {25, .24, 0, 0, 0},
	{45, 2, 1, 430}: {28, .24, 0, 0, 0},
	// staff
	{45, 7, 0, 0}:   {19, .325, 0, 0, 0},
	{45, 7, 0, 250}: {24, .325, 0, 0, 0},
	{45, 7, 0, 300}: {30, .325, 0, 0, 0},
	{45, 7, 0, 325}: {35, .325, 0, 0, 0},
	{45, 7, 0, 350}: {40, .325, 0, 0, 0},
	{45, 7, 0, 370}: {46, .325, 0, 0, 0},
	{45, 7, 0, 400}: {51, .325, 0, 0, 0},
	{45, 7, 0, 420}: {54, .325, 0, 0, 0},
	{45, 7, 0, 430}: {57, .325, 0, 0, 0},
	// ua
	{45, 1, 0, 0}:   {17, .43, 0, 0, 0},
	{45, 1, 0, 250}: {23, .43, 0, 0, 0},
	{45, 1, 0, 300}: {27, .43, 0, 0, 0},
	{45, 1, 0, 325}: {31, .43, 0, 0, 0},
	{45, 1, 0, 350}: {35, .43, 0, 0, 0},
	{45, 1, 0, 370}: {40, .43, 0, 0, 0},
	{45, 1, 0, 400}: {44, .43, 0, 0, 0},
	{45, 1, 0, 420}: {46, .43, 0, 0, 0},
	{45, 1, 0, 430}: {48, .43, 0, 0, 0},

	// finesse weaponry (skill 46) http://acpedia.org/wiki/Finesse_Weaponry
	// axe
	{46, 3, 0, 0}:   {22, .80, 0, 0, 0},
	{46, 3, 0, 250}: {28, .80, 0, 0, 0},
	{46, 3, 0, 300}: {33, .80, 0, 0, 0},
	{46, 3, 0, 325}: {39, .80, 0, 0, 0},
	{46, 3, 0, 350}: {44, .80, 0, 0, 0},
	{46, 3, 0, 370}: {50, .80, 0, 0, 0},
	{46, 3, 0, 400}: {55, .80, 0, 0, 0},
	{46, 3, 0, 420}: {57, .80, 0, 0, 0},
	{46, 3, 0, 430}: {61, .80, 0, 0, 0},
	// dagger
	{46, 6, 0, 0}:   {18, .42, 0, 0, 0},
	{46, 6, 0, 250}: {24, .42, 0, 0, 0},
	{46, 6, 0, 300}: {29, .42, 0, 0, 0},
	{46, 6, 0, 325}: {35, .42, 0, 0, 0},
	{46, 6, 0, 350}: {40, .42, 0, 0, 0},
	{46, 6, 0, 370}: {46, .42, 0, 0, 0},
	{46, 6, 0, 400}: {51, .42, 0, 0, 0},
	{46, 6, 0, 420}: {54, .42, 0, 0, 0},
	{46, 6, 0, 430}: {58, .42, 0, 0, 0},
	// msdagger
	{46, 6, 1, 0}:   {7, .24, 0, 0, 0},
	{46, 6, 1, 250}: {11, .24, 0, 0, 0},
	{46, 6, 1, 300}: {13, .24, 0, 0, 0},
	{46, 6, 1, 325}: {16, .24, 0, 0, 0},
	{46, 6, 1, 350}: {18, .24, 0, 0, 0},
	{46, 6, 1, 370}: {21, .24, 0, 0, 0},
	{46, 6, 1, 400}: {24, .24, 0, 0, 0},
	{46, 6, 1, 420}: {27, .24, 0, 0, 0},
	{46, 6, 1, 430}: {28, .24, 0, 0, 0},
	// mace
	{46, 4, 0, 0}:   {19, .23, 0, 0, 0},
	{46, 4, 0, 250}: {24, .23, 0, 0, 0},
	{46, 4, 0, 300}: {29, .23, 0, 0, 0},
	{46, 4, 0, 325}: {35, .23, 0, 0, 0},
	{46, 4, 0, 350}: {40, .23, 0, 0, 0},
	{46, 4, 0, 370}: {45, .23, 0, 0, 0},
	{46, 4, 0, 400}: {50, .23, 0, 0, 0},
	{46, 4, 0, 420}: {53, .23, 0, 0, 0},
	{46, 4, 0, 430}: {57, .23, 0, 0, 0},
	// spear
	{46, 5, 0, 0}:   {21, .65, 0, 0, 0},
	{46, 5, 0, 250}: {26, .65, 0, 0, 0},
	{46, 5, 0, 300}: {32, .65, 0, 0, 0},
	{46, 5, 0, 325}: {37, .65, 0, 0, 0},
	{46, 5, 0, 350}: {42, .65, 0, 0, 0},
	{46, 5, 0, 370}: {48, .65, 0, 0, 0},
	{46, 5, 0, 400}: {53, .65, 0, 0, 0},
	{46, 5, 0, 420}: {57, .65, 0, 0, 0},
	{46, 5, 0, 430}: {60, .65, 0, 0, 0},
	// sword
	{46, 2, 0, 0}:   {20, .42, 0, 0, 0},
	{46, 2, 0, 250}: {25, .42, 0, 0, 0},
	{46, 2, 0, 300}: {31, .42, 0, 0, 0},
	{46, 2, 0, 325}: {36, .42, 0, 0, 0},
	{46, 2, 0, 350}: {41, .42, 0, 0, 0},
	{46, 2, 0, 370}: {47, .42, 0, 0, 0},
	{46, 2, 0, 400}: {52, .42, 0, 0, 0},
	{46, 2, 0, 420}: {55, .42, 0, 0, 0},
	{46, 2, 0, 430}: {58, .42, 0, 0, 0},
	// mssword
	{46, 2, 1, 0}:   {7, .24, 0, 0, 0},
	{46, 2, 1, 250}: {10, .24, 0, 0, 0},
	{46, 2, 1, 300}: {13, .24, 0, 0, 0},
	{46, 2, 1, 325}: {16, .24, 0, 0, 0},
	{46, 2, 1, 350}: {18, .24, 0, 0, 0},
	{46, 2, 1, 370}: {21, .24, 0, 0, 0},
	{46, 2, 1, 400}: {24, .24, 0, 0, 0},
	{46, 2, 1, 420}: {25, .24, 0, 0, 0},
	{46, 2, 1, 430}: {28, .24, 0, 0, 0},
	// staff
	{46, 7, 0, 0}:   {19, .325, 0, 0, 0},
	{46, 7, 0, 250}: {24, .325, 0, 0, 0},
	{46, 7, 0, 300}: {30, .325, 0, 0, 0},
	{46, 7, 0, 325}: {35, .325, 0, 0, 0},
	{46, 7, 0, 350}: {40, .325, 0, 0, 0},
	{46, 7, 0, 370}: {46, .325, 0, 0, 0},
	{46, 7, 0, 400}: {51, .325, 0, 0, 0},
	{46, 7, 0, 420}: {54, .325, 0, 0, 0},
	{46, 7, 0, 430}: {57, .325, 0, 0, 0},
	// ua
	{46, 1, 0, 0}:   {17, .43, 0, 0, 0},
	{46, 1, 0, 250}: {23, .43, 0, 0, 0},
	{46, 1, 0, 300}: {27, .43, 0, 0, 0},
	{46, 1, 0, 325}: {31, .43, 0, 0, 0},
	{46, 1, 0, 350}: {35, .43, 0, 0, 0},
	{46, 1, 0, 370}: {40, .43, 0, 0, 0},
	{46, 1, 0, 400}: {44, .43, 0, 0, 0},
	{46, 1, 0, 420}: {46, .43, 0, 0, 0},
	{46, 1, 0, 430}: {48, .43, 0, 0, 0},

	// twohanded (skill 41) http://acpedia.org/wiki/Two_Handed_Weaponry
	// cleaver
	{41, 11, 1, 0}:   {13, .30, 0, 0, 0},
	{41, 11, 1, 250}: {17, .30, 0, 0, 0},
	{41, 11, 1, 300}: {22, .30, 0, 0, 0},
	{41, 11, 1, 325}: {26, .30, 0, 0, 0},
	{41, 11, 1, 350}: {30, .30, 0, 0, 0},
	{41, 11, 1, 370}: {35, .30, 0, 0, 0},
	{41, 11, 1, 400}: {39, .30, 0, 0, 0},
	{41, 11, 1, 420}: {42, .30, 0, 0, 0},
	{41, 11, 1, 430}: {45, .30, 0, 0, 0},
	// spear
	{41, 11, 0, 0}:   {14, .35, 0, 0, 0},
	{41, 11, 0, 250}: {19, .35, 0, 0, 0},
	{41, 11, 0, 300}: {24, .35, 0, 0, 0},
	{41, 11, 0, 325}: {29, .35, 0, 0, 0},
	{41, 11, 0, 350}: {33, .35, 0, 0, 0},
	{41, 11, 0, 370}: {37, .35, 0, 0, 0},
	{41, 11, 0, 400}: {42, .35, 0, 0, 0},
	{41, 11, 0, 420}: {45, .35, 0, 0, 0},
	{41, 11, 0, 430}: {48, .35, 0, 0, 0},

	// missile (skill 47) http://acpedia.org/wiki/Missile_Weaponry/Bows
	// bow (mastery 8)
	{47, 8, 0, 0}:   {0, 0, 110, 0, 0},
	{47, 8, 0, 250}: {0, 0, 120, 0, 0},
	{47, 8, 0, 270}: {0, 0, 130, 0, 0},
	{47, 8, 0, 290}: {0, 0, 140, 0, 0},
	{47, 8, 0, 315}: {0, 0, 140, 5, 0},
	{47, 8, 0, 335}: {0, 0, 140, 9, 0},
	{47, 8, 0, 360}: {0, 0, 140, 16, 0},
	{47, 8, 0, 375}: {0, 0, 140, 19, 0},
	{47, 8, 0, 385}: {0, 0, 140, 22, 0},
	// xbow (mastery 9)
	{47, 9, 0, 0}:   {0, 0, 140, 0, 0},
	{47, 9, 0, 250}: {0, 0, 150, 0, 0},
	{47, 9, 0, 270}: {0, 0, 155, 0, 0},
	{47, 9, 0, 290}: {0, 0, 165, 0, 0},
	{47, 9, 0, 315}: {0, 0, 165, 5, 0},
	{47, 9, 0, 335}: {0, 0, 165, 9, 0},
	{47, 9, 0, 360}: {0, 0, 165, 16, 0},
	{47, 9, 0, 375}: {0, 0, 165, 19, 0},
	{47, 9, 0, 385}: {0, 0, 165, 22, 0},
	// thrown (mastery 10)
	{47, 10, 0, 0}:   {0, 0, 130, 0, 0},
	{47, 10, 0, 250}: {0, 0, 140, 0, 0},
	{47, 10, 0, 270}: {0, 0, 150, 0, 0},
	{47, 10, 0, 290}: {0, 0, 160, 0, 0},
	{47, 10, 0, 315}: {0, 0, 160, 5, 0},
	{47, 10, 0, 335}: {0, 0, 160, 9, 0},
	{47, 10, 0, 360}: {0, 0, 160, 16, 0},
	{47, 10, 0, 375}: {0, 0, 160, 19, 0},
	{47, 10, 0, 385}: {0, 0, 160, 22, 0},

	// wands (skill 34 war / 43 void) http://acpedia.org/wiki/Magic_Casters
	{34, 0, 0, 290}: {0, 0, 0, 0, 1.03},
	{34, 0, 0, 315}: {0, 0, 0, 0, 1.06},
	{34, 0, 0, 335}: {0, 0, 0, 0, 1.09},
	{34, 0, 0, 360}: {0, 0, 0, 0, 1.13},
	{34, 0, 0, 375}: {0, 0, 0, 0, 1.16},
	{34, 0, 0, 385}: {0, 0, 0, 0, 1.18},

	{43, 0, 0, 290}: {0, 0, 0, 0, 1.03},
	{43, 0, 0, 315}: {0, 0, 0, 0, 1.06},
	{43, 0, 0, 335}: {0, 0, 0, 0, 1.09},
	{43, 0, 0, 360}: {0, 0, 0, 0, 1.13},
	{43, 0, 0, 375}: {0, 0, 0, 0, 1.16},
	{43, 0, 0, 385}: {0, 0, 0, 0, 1.18},
	// void vr wand - not sure why this is different (mastery 12)
	{43, 12, 0, 385}: {0, 0, 0, 0, 1.18},
}

// spellEffect mirrors UB's SpellInfo(key, change, bonus) (Dictionaries.cs:356):
// `change` is what the active enchantment adds to the shown value (subtracted
// to un-buff), `bonus` is what the spell grants when innate on the item (0 for
// the 2012 aura-converted item spells).
type odSpellEffect struct {
	change float64
	bonus  float64
}

// maxDamageSpellEffects is transcribed from UB Dictionaries.cs
// LongValueKeySpellEffects entries keyed on LongValueKey_MaxDamage (218103842).
var maxDamageSpellEffects = map[int]odSpellEffect{
	1616: {20, 0},  // Blood Drinker VI
	2096: {22, 0},  // Infected Caress
	5183: {24, 0},  // Incantation of Blood Drinker (post Feb-2013)
	4395: {24, 0},  // Incantation of Blood Drinker (post Feb-2013)
	2598: {2, 2},   // Minor Blood Thirst
	2586: {4, 4},   // Major Blood Thirst
	4661: {7, 7},   // Epic Blood Thirst
	6089: {10, 10}, // Legendary Blood Thirst
	3688: {300, 0}, // Prodigal Blood Drinker
}

// elemVsMonSpellEffects is transcribed from UB Dictionaries.cs
// DoubleValueKeySpellEffects entries keyed on DoubleValueKey_ElementalDamageVersusMonsters (152).
var elemVsMonSpellEffects = map[int]odSpellEffect{
	3258: {.06, 0},   // Spirit Drinker VI
	3259: {.07, 0},   // Infected Spirit Caress
	5182: {.08, 0},   // Incantation of Spirit Drinker (post Feb-2013)
	4414: {.08, 0},   // Incantation of Spirit Drinker (post Feb-2013)
	3251: {.01, .01}, // Minor Spirit Thirst
	3250: {.03, .03}, // Major Spirit Thirst
	4670: {.05, .05}, // Epic Spirit Thirst
	6098: {.07, .07}, // Legendary Spirit Thirst
}

// buffedMaxDamage mirrors GetBuffedIntValueKey(218103842): base value minus
// `change` for each active spell (un-buff the enchantment), plus `bonus` for
// each innate spell.
func buffedMaxDamage(raw, iv map[string]any) int {
	value := ivI(iv, "218103842", 0)
	for _, id := range toIntList(raw["ActiveSpells"]) {
		if e, ok := maxDamageSpellEffects[id]; ok {
			value -= int(e.change)
		}
	}
	for _, id := range toIntList(raw["Spells"]) {
		if e, ok := maxDamageSpellEffects[id]; ok {
			value += int(e.bonus)
		}
	}
	return value
}

// buffedElemVsMon mirrors GetBuffedDoubleValueKey(152) using the same
// subtract-change-for-active / add-bonus-for-innate semantics.
func buffedElemVsMon(raw, dv map[string]any) float64 {
	value := dvF(dv, "152", 0)
	for _, id := range toIntList(raw["ActiveSpells"]) {
		if e, ok := elemVsMonSpellEffects[id]; ok {
			value -= e.change
		}
	}
	for _, id := range toIntList(raw["Spells"]) {
		if e, ok := elemVsMonSpellEffects[id]; ok {
			value += e.bonus
		}
	}
	return value
}

// isMultiStrike mirrors MiscCalcs.GetMaxProperty's MultiStrike detection:
// IntValues[47] (WeaponType master id) ∈ {160,166,486}, or (==4 and Mastery==11).
func isMultiStrike(iv map[string]any) int {
	wt := ivI(iv, "47", 0)
	if wt == 160 || wt == 166 || wt == 486 {
		return 1
	}
	if wt == 4 && ivI(iv, "353", 0) == 11 {
		return 1
	}
	return 0
}

func round2(x float64) float64 {
	return math.Round(x*100) / 100
}

// computeOD ports UB's OD display formulas (ItemInfo.cs CalcMeleeDamage /
// CalcMissileDamage + the OD lines ~631-647). Returns (0, false) when OD does
// not apply: non weapon/wand object class, non-loot-gen item (no
// SalvageWorkmanship), or an unrecognized (skill, mastery, multiStrike,
// wieldReq) tier (exact match only — no nearest-tier rounding).
func computeOD(raw map[string]any) (float64, bool) {
	oc := rawI(raw, "ObjectClass", 0)
	if oc != 1 && oc != 9 && oc != 31 {
		return 0, false
	}

	iv := bag(raw, "IntValues")
	dv := bag(raw, "DoubleValues")

	// Gate: OD only applies to loot-gen items.
	if dvF(dv, "167772169", 0) <= 0 {
		return 0, false
	}

	key := bestKey{
		skill:       ivI(iv, "159", 0),
		mastery:     ivI(iv, "353", 0),
		multiStrike: isMultiStrike(iv),
		wieldReq:    ivI(iv, "160", 0),
	}
	bv, ok := bestValues[key]
	if !ok && oc == 31 {
		// Wands: our probe showed some wands lack key 353 (mastery), which
		// defaults to 0 via ivI — but retry explicitly with mastery 0 so the
		// void VR wand row (43,12,...) stays reachable while items that
		// genuinely carry a different mastery value still fall back to the
		// normal (34|43, 0, ...) rows.
		key.mastery = 0
		bv, ok = bestValues[key]
	}
	if !ok {
		return 0, false
	}

	switch oc {
	case 1: // melee
		variance := dvF(dv, "167772171", 0)
		if variance <= 0 {
			return 0, false
		}
		// UB ItemInfo.cs:1096: Math.Log(perfectVariance / Variance, 0.8).
		// Table MaxVar is the tier's baseline variance; lower variance than
		// baseline yields negative varianceTinks, i.e. a positive OD credit.
		varianceTinks := round2(math.Log(bv.maxVar/variance) / math.Log(0.8))
		od := float64(buffedMaxDamage(raw, iv)) - varianceTinks - bv.maxDmg
		return round2(od), true

	case 9: // missile
		var arrowMax float64
		switch ivI(iv, "353", 0) {
		case 8:
			arrowMax = 40
		case 9:
			arrowMax = 53
		case 10:
			arrowMax = 42
		default:
			arrowMax = 0
		}

		tinks := ivI(iv, "171", 0)
		imbued := ivI(iv, "179", 0)
		var remaining int
		if tinks == 0 {
			remaining = 9
		} else {
			remaining = 10 - tinks
			if imbued == 0 {
				remaining--
			}
		}
		if remaining < 0 {
			remaining = 0
		}

		dmgMod := dvF(dv, "167772174", 0)*100 - 100
		bDmg := float64(buffedMaxDamage(raw, iv))
		if bDmg <= 10 {
			bDmg += 24
		}
		bElem := float64(ivI(iv, "204", 0))
		maxMod := (bv.maxDmgMod + 136) / 100

		od := (1+(dmgMod+4*float64(remaining))/100)*(bElem+bDmg+arrowMax)/maxMod - (bv.maxElemBonus + 24 + arrowMax)
		return round2(od), true

	case 31: // wand
		od := (buffedElemVsMon(raw, dv) - bv.maxElemVsMon) * 100
		return round2(od), true
	}

	return 0, false
}