diff --git a/disenchant.lua b/disenchant.lua
new file mode 100644
index 0000000..97e7893
--- /dev/null
+++ b/disenchant.lua
@@ -0,0 +1,187 @@
+local private, public = {}, {}
+Aux.disenchant = public
+
+function public.source(item_id)
+
+    local info = {
+        [10940] = {'DUST', '1-20'},
+        [11083] = {'DUST', '21-30'},
+        [11137] = {'DUST', '31-40'},
+        [11176] = {'DUST', '41-50'},
+        [16204] = {'DUST', '51-60'},
+
+        [10938] = {'ESSENCE', '1-10'},
+        [10939] = {'ESSENCE', '11-15'},
+        [10998] = {'ESSENCE', '16-20'},
+        [11082] = {'ESSENCE', '21-25'},
+        [11134] = {'ESSENCE', '26-30'},
+        [11135] = {'ESSENCE', '31-35'},
+        [11174] = {'ESSENCE', '36-40'},
+        [11175] = {'ESSENCE', '41-45'},
+        [16202] = {'ESSENCE', '46-50'},
+        [16203] = {'ESSENCE', '51-60'},
+
+        [10978] = {'SHARD', '1-20'},
+        [11084] = {'SHARD', '21-25'},
+        [11138] = {'SHARD', '26-30'},
+        [11139] = {'SHARD', '31-35'},
+        [11177] = {'SHARD', '36-40'},
+        [11178] = {'SHARD', '41-45'},
+        [14343] = {'SHARD', '46-50'},
+        [14344] = {'SHARD', '51-60'},
+
+        [20725] = {'CRYSTAL', '51+'},
+    }
+
+    return unpack(info[item_id] or {})
+end
+
+local armor = {
+    INVTYPE_HEAD = true,
+    INVTYPE_NECK = true,
+    INVTYPE_SHOULDER = true,
+    INVTYPE_BODY = true,
+    INVTYPE_CHEST = true,
+    INVTYPE_ROBE = true,
+    INVTYPE_WAIST = true,
+    INVTYPE_LEGS = true,
+    INVTYPE_FEET = true,
+    INVTYPE_WRIST = true,
+    INVTYPE_HAND = true,
+    INVTYPE_FINGER = true,
+    INVTYPE_TRINKET = true,
+    INVTYPE_CLOAK = true,
+    INVTYPE_HOLDABLE = true,
+}
+
+local weapon = {
+    INVTYPE_2HWEAPON = true,
+    INVTYPE_WEAPONMAINHAND = true,
+    INVTYPE_WEAPON = true,
+    INVTYPE_WEAPONOFFHAND = true,
+    INVTYPE_SHIELD = true,
+    INVTYPE_RANGED = true,
+    INVTYPE_RANGEDRIGHT = true,
+}
+
+local UNCOMMON, RARE, EPIC = 2, 3, 4
+
+function public.value(slot, quality, level)
+    local expectation
+    for _, event in public.distribution(slot, quality, level) do
+        local value = Aux.history.value(event.item_id..':'..0)
+        if not value then
+            return
+        else
+            expectation = (expectation or 0) + event.probability * event.quantity * value
+        end
+    end
+    return expectation
+end
+
+function public.distribution(slot, quality, level)
+    if not (armor[slot] or weapon[slot]) then
+        return {}
+    end
+
+    local function p(probability_weapon, probability_armor)
+        if armor[slot] then
+            return probability_armor
+        elseif weapon[slot] then
+            return probability_weapon
+        end
+    end
+
+    if quality == UNCOMMON then
+        if level <= 10 then
+            return {
+                {item_id=10940, quantity=1.5, probability=0.8},
+                {item_id=10938, quantity=1.5, probability=0.2},
+            }
+        elseif level <= 15 then
+            return {
+                {item_id=10940, quantity=2.5, probability=p(0.75, 0.2)},
+                {item_id=10939, quantity=1.5, probability=p(0.2, 0.75)},
+                {item_id=10978, quantity=1, probability=0.05},
+            }
+        elseif level <= 20 then
+            return {
+                {item_id=10940, quantity=5, probability=p(0.75, 0.15)},
+                {item_id=10998, quantity=1.5, probability=p(0.15, 0.75)},
+                {item_id=10978, quantity=1, probability=0.10},
+            }
+        elseif level <= 25 then
+            return {
+                {item_id=11083, quantity=1.5, probability=p(0.75, 0.2)},
+                {item_id=11082, quantity=1.5, probability=p(0.2, 0.75)},
+                {item_id=11084, quantity=1, probability=0.05},
+            }
+        elseif level <= 30 then
+            return {
+                {item_id=11083, quantity=3.5, probability=p(0.75, 0.2)},
+                {item_id=11134, quantity=1.5, probability=p(0.2, 0.75)},
+                {item_id=11138, quantity=1, probability=0.05},
+            }
+        elseif level <= 35 then
+            return {
+                {item_id=11137, quantity=1.5, probability=p(0.75, 0.2)},
+                {item_id=11135, quantity=1.5, probability=p(0.2, 0.75)},
+                {item_id=11139, quantity=1, probability=0.05},
+            }
+        elseif level <= 40 then
+            return {
+                {item_id=11137, quantity=3.5, probability=p(0.75, 0.2)},
+                {item_id=11174, quantity=1.5, probability=p(0.2, 0.75)},
+                {item_id=11177, quantity=1, probability=0.05},
+            }
+        elseif level <= 45 then
+            return {
+                {item_id=11176, quantity=1.5, probability=p(0.75, 0.2)},
+                {item_id=11175, quantity=1.5, probability=p(0.2, 0.75)},
+                {item_id=11178, quantity=1, probability=0.05},
+            }
+        elseif level <= 50 then
+            return {
+                {item_id=11176, quantity=3.5, probability=p(0.75, 0.22)},
+                {item_id=16202, quantity=1.5, probability=p(0.2, 0.75)},
+                {item_id=14343, quantity=1, probability=p(0.05, 0.03)},
+            }
+        elseif level <= 55 then
+            return {
+                {item_id=16204, quantity=1.5, probability=p(0.75, 0.22)},
+                {item_id=16203, quantity=1.5, probability=p(0.2, 0.75)},
+                {item_id=14344, quantity=1, probability=p(0.05, 0.03)},
+            }
+        elseif level <= 60 then
+            return {
+                {item_id=16204, quantity=3.5, probability=p(0.75, 0.22)},
+                {item_id=16203, quantity=2.5, probability=p(0.2, 0.75)},
+                {item_id=14344, quantity=1, probability=p(0.05, 0.03)},
+            }
+        end
+    elseif quality == RARE then
+        if level <= 20 then
+            return {{item_id=10978, quantity=1, probability=1}}
+        elseif level <= 25 then
+            return {{item_id=11084, quantity=1, probability=1}}
+        elseif level <= 30 then
+            return {{item_id=11138, quantity=1, probability=1}}
+        elseif level <= 35 then
+            return {{item_id=11139, quantity=1, probability=1}}
+        elseif level <= 40 then
+            return {{item_id=11177, quantity=1, probability=1}}
+        elseif level <= 45 then
+            return {{item_id=11178, quantity=1, probability=1}}
+        elseif level <= 50 then
+            return {{item_id=14343, quantity=1, probability=1}}
+        elseif level <= 55 then
+            return {{item_id=14344, quantity=1, probability=0.995}, {item_id=20725, quantity=1, probability=0.005}}
+        elseif level <= 60 then
+            return {{item_id=14344, quantity=1, probability=0.995}, {item_id=20725, quantity=1, probability=0.005}}
+        end
+    elseif quality == EPIC then
+        return {{item_id=20725, quantity=1, probability=1}}
+    end
+
+    return {}
+end
\ No newline at end of file