attack_table.py

def calc(roll, miss, crit, dodge, parry, hit):
    roll += hit
    roll -= parry
    if roll < 0.0:
        return 'parry'
    roll -= dodge
    if roll < 0.0:
        return 'dodge'
    roll -= miss
    if roll < 0.0:
        return 'miss'
    if roll < crit:
        return 'crit'
    return 'hit'
        
attacker = {
  "skills": {
    "defence": 75,
    "swords": 75,
  },
  "crit_rating": 500,
  "hit_rating": 500,
}

defender = {
  "skills": {
    "defence": 75,
  },
  "parry_rating": 400,
  "dodge_rating": 400,
}
  
base_miss_chance = 0.20
base_crit_chance = 0.05
base_dodge_chance = 0.175
base_parry_chance = 0.175


miss_chance = base_miss_chance + (defender["skills"]["defence"] / 1000.0)
crit_chance = base_crit_chance + (attacker["crit_rating"] / 10000.0)
dodge_chance = base_dodge_chance + (defender["dodge_rating"] / 10000.0)
parry_chance = base_parry_chance + (defender["parry_rating"] / 10000.0)
bonus_hit = (attacker["skills"]["swords"] / 1000.0)

print('miss_chance', miss_chance)
print('crit_chance', crit_chance)
print('dodge_chance', dodge_chance)
print('parry_chance', parry_chance)
print('bonus_hit', bonus_hit)

from random import random as rand

atk1, atk2, atk3 = rand(), rand(), rand()
for atk in (atk1, atk2, atk3):
    res = calc(atk, miss_chance, crit_chance, dodge_chance, parry_chance, bonus_hit)
    print(atk, res)