package game

import (
	"math/rand"
	"time"

	"github.com/denisovdennis/autohero/internal/model"
	"github.com/denisovdennis/autohero/internal/tuning"
)

// ReferenceGearProfile selects how ilvl/rarity are chosen for balance simulations.
type ReferenceGearProfile int

const (
	// ReferenceGearMedian uses ilvl == hero level and common Iron Sword + Chainmail (deterministic, low noise).
	ReferenceGearMedian ReferenceGearProfile = iota
	// ReferenceGearRolled uses RollIlvl(level, false) per slot with rng (matches base-monster drop spread).
	ReferenceGearRolled
)

// NewReferenceHeroForBalance builds a hero at the given level with sword + medium chest
// scaled per spec §6.4 (IlvlFactor, RarityMultiplier). Stats follow the same level-up path
// as gameplay (LevelUp cadences from tuning). HP is set to MaxHP for a fresh fight.
// rng is used when profile is ReferenceGearRolled; may be nil for ReferenceGearMedian.
func NewReferenceHeroForBalance(level int, profile ReferenceGearProfile, rng *rand.Rand) *model.Hero {
	if level < 1 {
		level = 1
	}
	h := &model.Hero{
		ID:           1,
		Name:         "BalanceRef",
		HP:           100,
		MaxHP:        100,
		Attack:       10,
		Defense:      5,
		Speed:        1.0,
		Strength:     1,
		Constitution: 1,
		Agility:      1,
		Luck:         1,
		State:        model.StateWalking,
		Level:        1,
		Gear:         make(map[model.EquipmentSlot]*model.GearItem),
	}
	for h.Level < level {
		h.XP = model.XPToNextLevel(h.Level)
		h.LevelUp()
	}
	h.HP = h.MaxHP

	wIlvl, aIlvl := level, level
	if profile == ReferenceGearRolled {
		if rng == nil {
			rng = rand.New(rand.NewSource(1))
		}
		wIlvl = rollIlvlForBalance(level, false, rng)
		aIlvl = rollIlvlForBalance(level, false, rng)
	}

	// Typical mid-tier drops: uncommon sword + mail (catalog bases; slightly above 10 for elite/DoT balance targets).
	const refGearBase = 12
	wPrimary := model.ScalePrimary(refGearBase, wIlvl, model.RarityUncommon)
	h.Gear[model.SlotMainHand] = &model.GearItem{
		Slot:          model.SlotMainHand,
		FormID:        "gear.form.main_hand.sword",
		Name:          "Steel Sword",
		Subtype:       "sword",
		Rarity:        model.RarityUncommon,
		Ilvl:          wIlvl,
		BasePrimary:   refGearBase,
		PrimaryStat:   wPrimary,
		StatType:      "attack",
		SpeedModifier: 1.0,
		CritChance:    0.05,
	}
	aPrimary := model.ScalePrimary(refGearBase, aIlvl, model.RarityUncommon)
	h.Gear[model.SlotChest] = &model.GearItem{
		Slot:          model.SlotChest,
		FormID:        "gear.form.chest.medium",
		Name:          "Reinforced Mail",
		Subtype:       "medium",
		Rarity:        model.RarityUncommon,
		Ilvl:          aIlvl,
		BasePrimary:   refGearBase,
		PrimaryStat:   aPrimary,
		StatType:      "defense",
		SpeedModifier: 1.0,
	}

	now := time.Now()
	h.RefreshDerivedCombatStats(now)
	return h
}

// CloneHeroForCombatSim returns a deep enough copy for ResolveCombatToEnd (gear items copied).
func CloneHeroForCombatSim(h *model.Hero) *model.Hero {
	if h == nil {
		return nil
	}
	cp := *h
	if h.Gear != nil {
		cp.Gear = make(map[model.EquipmentSlot]*model.GearItem, len(h.Gear))
		for k, v := range h.Gear {
			if v != nil {
				gv := *v
				cp.Gear[k] = &gv
			} else {
				cp.Gear[k] = nil
			}
		}
	}
	return &cp
}

// PrepareHeroForAdminCombatSim returns a clone of h for the admin combat simulator: gear copied,
// all buffs and debuffs cleared, derived stats refreshed from base+gear only, HP set to max,
// state normalized to walking (fresh duel — ignores in-combat / resting flags on the source snapshot).
// Does not persist; does not mutate h.
// combatTimelineStart should match the start time passed to ResolveCombatToEndWithDuration (e.g. CombatSimDeterministicStart); if zero, time.Now() is used.
func PrepareHeroForAdminCombatSim(h *model.Hero, combatTimelineStart time.Time) *model.Hero {
	hero := CloneHeroForCombatSim(h)
	if hero == nil {
		return nil
	}
	hero.Buffs = nil
	hero.Debuffs = nil
	hero.DebuffCatalog = nil
	now := combatTimelineStart
	if now.IsZero() {
		now = time.Now()
	}
	hero.State = model.StateWalking
	hero.RefreshDerivedCombatStats(now)
	if hero.MaxHP <= 0 {
		hero.MaxHP = 1
	}
	hero.HP = hero.MaxHP
	return hero
}

// rollIlvlForBalance mirrors model.RollIlvl but uses rng for deterministic simulations.
func rollIlvlForBalance(monsterLevel int, isElite bool, rng *rand.Rand) int {
	var delta int
	if isElite {
		r := rng.Float64()
		cfg := tuning.Get()
		switch {
		case r < cfg.RollIlvlEliteBaseChance:
			delta = 0
		case r < cfg.RollIlvlEliteBaseChance+cfg.RollIlvlElitePlusOneChance:
			delta = 1
		default:
			delta = 2
		}
	} else {
		delta = rng.Intn(3) - 1
	}
	ilvl := monsterLevel + delta
	if ilvl < 1 {
		ilvl = 1
	}
	return ilvl
}