package main

import (
	"fmt"
	"math/bits"
	"strings"
)

// Port of main.py's sophisticated equipment-slot translation, used to emit the
// `slot_name` field. This is load-bearing for the suitbuilder: jewelry items get
// an empty computed_slot_name (their EquipMask isn't an armor-coverage value, so
// the SQL CONCAT_WS yields ''), and load_items falls back to slot_name
// (`computed_slot_name or slot_name`) to bucket them as Left Ring / Neck / etc.

// equipMaskEntry is one EquipMask enum row, kept in ascending-mask order so the
// bit-flag decode joins parts deterministically (Left before Right).
type equipMaskEntry struct {
	Mask int
	Name string
}

// equipFriendly maps technical EquipMask names to display names
// (translate_equipment_slot's name_mapping, identical in both branches).
var equipFriendly = map[string]string{
	"HeadWear": "Head", "ChestWear": "Chest", "ChestArmor": "Chest",
	"AbdomenWear": "Abdomen", "AbdomenArmor": "Abdomen",
	"UpperArmWear": "Upper Arms", "UpperArmArmor": "Upper Arms",
	"LowerArmWear": "Lower Arms", "LowerArmArmor": "Lower Arms",
	"HandWear": "Hands", "UpperLegWear": "Upper Legs", "UpperLegArmor": "Upper Legs",
	"LowerLegWear": "Lower Legs", "LowerLegArmor": "Lower Legs", "FootWear": "Feet",
	"NeckWear": "Neck", "WristWearLeft": "Left Wrist", "WristWearRight": "Right Wrist",
	"FingerWearLeft": "Left Ring", "FingerWearRight": "Right Ring",
	"MeleeWeapon": "Melee Weapon", "Shield": "Shield", "MissileWeapon": "Missile Weapon",
	"MissileAmmo": "Ammo", "Held": "Held", "TwoHanded": "Two-Handed",
	"TrinketOne": "Trinket", "Cloak": "Cloak", "Robe": "Robe",
}

var commonSlots = map[int]string{
	30:     "Shirt",
	786432: "Left Ring, Right Ring",
	262144: "Left Ring",
	524288: "Right Ring",
}

func friendlySlot(name string) string {
	if f, ok := equipFriendly[name]; ok {
		return f
	}
	return name
}

func isBodyArmorEquipMask(v int) bool     { return v&0x00007F21 != 0 }
func isBodyArmorCoverageMask(v int) bool  { return v&0x0001FF00 != 0 }
func totalBitsSet(v int) int              { return bits.OnesCount(uint(uint32(v))) }

// getCoverageReductionOptions mirrors main.py:658.
func getCoverageReductionOptions(coverage int) []int {
	const (
		oUpperArms = 4096
		oLowerArms = 8192
		oUpperLegs = 256
		oLowerLegs = 512
		oChest     = 1024
		oAbdomen   = 2048
		head       = 16384
		hands      = 32768
		feet       = 65536
	)
	if totalBitsSet(coverage) <= 1 || !isBodyArmorCoverageMask(coverage) {
		return []int{coverage}
	}
	switch coverage {
	case oUpperArms | oLowerArms:
		return []int{oUpperArms, oLowerArms}
	case oUpperLegs | oLowerLegs:
		return []int{oUpperLegs, oLowerLegs}
	case oLowerLegs | feet:
		return []int{feet}
	case oChest | oAbdomen:
		return []int{oChest}
	case oChest | oAbdomen | oUpperArms:
		return []int{oChest}
	case oChest | oUpperArms | oLowerArms:
		return []int{oChest}
	case oChest | oUpperArms:
		return []int{oChest}
	case oAbdomen | oUpperLegs | oLowerLegs:
		return []int{oAbdomen, oUpperLegs, oLowerLegs}
	case oChest | oAbdomen | oUpperArms | oLowerArms:
		return []int{oChest}
	case oAbdomen | oUpperLegs:
		return []int{oAbdomen}
	}
	return []int{coverage}
}

// coverageToEquipMask mirrors main.py:717.
func coverageToEquipMask(coverage int) int {
	m := map[int]int{
		16384: 1, 1024: 512, 4096: 2048, 8192: 4096, 32768: 32,
		2048: 1024, 256: 8192, 512: 16384, 65536: 256,
	}
	if v, ok := m[coverage]; ok {
		return v
	}
	return coverage
}

// getSophisticatedSlotOptions mirrors main.py:734.
func getSophisticatedSlotOptions(equippableSlots, coverageValue int, hasMaterial bool) []int {
	const lowerLegWear, footWear = 128, 256
	if equippableSlots == (lowerLegWear | footWear) {
		return []int{footWear}
	}
	if isBodyArmorEquipMask(equippableSlots) && totalBitsSet(equippableSlots) > 1 {
		if !hasMaterial {
			return []int{equippableSlots}
		}
		var slotOpts []int
		for _, o := range getCoverageReductionOptions(coverageValue) {
			slotOpts = append(slotOpts, coverageToEquipMask(o))
		}
		if len(slotOpts) > 0 {
			return slotOpts
		}
		return []int{equippableSlots}
	}
	return []int{equippableSlots}
}

// translateEquipmentSlot mirrors main.py:807.
func (s *Server) translateEquipmentSlot(loc int) string {
	if loc == 0 {
		return "Inventory"
	}
	if name, ok := s.equipMaskMap[loc]; ok {
		return friendlySlot(name)
	}
	if cs, ok := commonSlots[loc]; ok {
		return cs
	}
	var parts []string
	for _, e := range s.equipMaskOrdered {
		if e.Mask > 0 && loc&e.Mask == e.Mask {
			parts = append(parts, friendlySlot(e.Name))
		}
	}
	if len(parts) > 0 {
		return strings.Join(parts, ", ")
	}
	if loc >= 268435456 {
		switch loc {
		case 268435456:
			return "Aetheria Blue"
		case 536870912:
			return "Aetheria Yellow"
		case 1073741824:
			return "Aetheria Red"
		default:
			return fmt.Sprintf("Special Slot (%d)", loc)
		}
	}
	return "-"
}

// computeSlotName mirrors the slot_name block in search_items (main.py:3977-4033).
func (s *Server) computeSlotName(equippableSlots, coverageValue int, hasMaterial bool) string {
	if equippableSlots <= 0 {
		return "-"
	}
	opts := getSophisticatedSlotOptions(equippableSlots, coverageValue, hasMaterial)
	var names []string
	for _, o := range opts {
		n := s.translateEquipmentSlot(o)
		if n != "" && !containsString(names, n) {
			names = append(names, n)
		}
	}
	if len(names) > 0 {
		return strings.Join(names, ", ")
	}
	return "-"
}