package world

import (
	"fmt"
	"log"
	"math/rand"
	"sort"
	"strings"

	"thehouseoficarus/internal/behavior"
)

type ObjState struct {
	Depleted     bool
	DepleteTimer float64
	DefID        string
	Name         string
	Aliases      []string
	Index        int
	// RoomID is where the instance currently is; HomeRoomID is the room that
	// declares it and never changes as it wanders. Identity (and re-seeding)
	// is anchored to HomeRoomID so a wandering object cannot be duplicated by
	// re-entering its home room.
	RoomID     int
	HomeRoomID int
	// Dynamic marks an instance created at runtime (AddObjInstance) rather
	// than declared by the room file. ReconcileRoomState must not prune these:
	// a live fire is not in the room's objects list and would be extinguished
	// by any content edit.
	Dynamic        bool
	JustRespawned  bool
	WanderRooms    []int
	WanderInterval float64
	WanderCounter  int
	SharedMax      float64
	SharedTimer    int
	Quality        float64

	SafespotLevel        int
	SafespotTicksAtLevel int
	SafespotOccupants    []string
}

type ObjMove struct {
	DefID    string
	Name     string
	FromRoom int
	ToRoom   int
}

func (w *World) ObjStateKey(roomID int, defID string, index int) string {
	return fmt.Sprintf("%d:%s:%d", roomID, defID, index)
}

func (w *World) EnsureObjectStates(roomID int, defIDs []string) {
	w.mu.Lock()
	defer w.mu.Unlock()
	w.ensureObjStates(roomID, defIDs)
}

func (w *World) ensureObjStates(roomID int, defIDs []string) {
	if w.objStates == nil {
		w.objStates = make(map[string]*ObjState)
	}
	counts := make(map[string]int)
	for _, defID := range defIDs {
		idx := counts[defID]
		counts[defID]++
		key := w.ObjStateKey(roomID, defID, idx)
		if _, exists := w.objStates[key]; exists {
			continue
		}
		// The object may simply be away from its home room (wandering): its
		// state lives under its current room's key, so re-seeding the home
		// room must not create a second, independent instance.
		if w.homeObjStateLocked(roomID, defID, idx) != nil {
			continue
		}
		w.objStates[key] = &ObjState{
			DefID:      defID,
			Name:       defID,
			Index:      idx,
			RoomID:     roomID,
			HomeRoomID: roomID,
		}
	}
}

// homeObjStateLocked returns the instance whose home room is roomID and whose
// identity is (defID, index), wherever it has currently wandered. It must be
// called with w.mu held.
func (w *World) homeObjStateLocked(roomID int, defID string, index int) *ObjState {
	for _, st := range w.objStates {
		if st.HomeRoomID == roomID && st.DefID == defID && st.Index == index {
			return st
		}
	}
	return nil
}

func (w *World) AddObjInstance(roomID int, defID string, quality float64) {
	w.mu.Lock()
	defer w.mu.Unlock()
	if w.objStates == nil {
		w.objStates = make(map[string]*ObjState)
	}
	idx := 0
	for {
		key := w.ObjStateKey(roomID, defID, idx)
		// An index is free only if no instance currently occupies it AND no
		// instance from this room has wandered away holding that index; reusing
		// a wandered index would collide when the wanderer returns.
		if _, exists := w.objStates[key]; !exists && w.homeObjStateLocked(roomID, defID, idx) == nil {
			w.objStates[key] = &ObjState{
				DefID:      defID,
				Name:       defID,
				Index:      idx,
				RoomID:     roomID,
				HomeRoomID: roomID,
				Dynamic:    true,
				Quality:    quality,
			}
			return
		}
		idx++
	}
}

// ReconcileRoomState brings a room's object instances and item-spawn ground
// entries in line with a (possibly just-edited) room definition, without a
// restart. Player-dropped ground items, dynamic object instances (fires), and
// live reservations are preserved. Mob instances live in MobStore and are
// reconciled by the game layer, which owns that store.
func (w *World) ReconcileRoomState(roomID int, room *Room) {
	w.mu.Lock()
	defer w.mu.Unlock()
	if w.objStates == nil {
		w.objStates = make(map[string]*ObjState)
	}

	// Prune room-declared instances the definition no longer declares. Prune
	// by home room so a wandered instance is reconciled where it belongs, and
	// never prune a dynamic instance.
	want := make(map[string]int, len(room.Objects))
	for _, ro := range room.Objects {
		want[ro.ID]++
	}
	for key, st := range w.objStates {
		if st.Dynamic || st.HomeRoomID != roomID {
			continue
		}
		if st.Index >= want[st.DefID] {
			delete(w.objStates, key)
		}
	}

	// Re-create declared instances that are missing (including ones that had
	// wandered away; ensureObjStates recognises them by HomeRoomID).
	defIDs := make([]string, 0, len(room.Objects))
	for _, ro := range room.Objects {
		defIDs = append(defIDs, ro.ID)
	}
	w.ensureObjStates(roomID, defIDs)

	// Ground spawns are only reconciled after the room has been seeded: before
	// that, the first entry seeds from the definition anyway, and adding
	// entries here would make SeedGroundItems double the quantity.
	if w.seeded[roomID] {
		w.reconcileGroundSpawnsLocked(roomID, room.ItemSpawns)
	}
}

// reconcileGroundSpawnsLocked adds entries for newly declared item spawns and
// drops entries for spawns the room no longer declares, leaving the live
// quantity of existing spawns (and every dropped item) untouched. It must be
// called with w.mu held.
func (w *World) reconcileGroundSpawnsLocked(roomID int, spawns []SpawnDef) {
	declared := make(map[string]bool, len(spawns))
	for _, s := range spawns {
		declared[strings.ToLower(s.ID)] = true
	}
	kept := w.groundItems[roomID][:0]
	for _, e := range w.groundItems[roomID] {
		if e.isSpawn && !declared[strings.ToLower(e.itemID)] {
			continue
		}
		kept = append(kept, e)
	}
	w.groundItems[roomID] = kept
	for _, s := range spawns {
		found := false
		for _, e := range w.groundItems[roomID] {
			if e.isSpawn && strings.EqualFold(e.itemID, s.ID) {
				found = true
				break
			}
		}
		if !found {
			w.groundItems[roomID] = append(w.groundItems[roomID], &groundEntry{
				itemID:       s.ID,
				quantity:     s.Quantity,
				isSpawn:      true,
				respawnDelay: spawnRespawnDelay(s.RespawnTicks),
				respawnQty:   s.Quantity,
			})
		}
	}
}

// RemoveObjInstanceIndex removes exactly one instance by identity
// (defID, index), looking it up by its current room first (roomID) and
// falling back to its home room in case it has wandered away. A room may
// legitimately declare the same object twice, so the index names which one;
// removing every instance of a defID would destroy a sibling.
func (w *World) RemoveObjInstanceIndex(roomID int, defID string, index int) {
	w.mu.Lock()
	defer w.mu.Unlock()
	if w.objStates == nil {
		return
	}
	key := w.ObjStateKey(roomID, defID, index)
	if st, ok := w.objStates[key]; ok && st.DefID == defID && st.Index == index {
		delete(w.objStates, key)
		return
	}
	for k, st := range w.objStates {
		if st.DefID == defID && st.Index == index && st.HomeRoomID == roomID {
			delete(w.objStates, k)
			return
		}
	}
}

func (w *World) AllFireStates() []*ObjState {
	w.mu.Lock()
	defer w.mu.Unlock()
	var out []*ObjState
	for _, st := range w.objStates {
		if st.DefID == "fire" && st.Quality > 0 {
			out = append(out, st)
		}
	}
	return out
}

func (w *World) GetObjState(roomID int, defID string, index int) *ObjState {
	w.mu.Lock()
	defer w.mu.Unlock()
	if w.objStates == nil {
		return nil
	}
	return w.objStates[w.ObjStateKey(roomID, defID, index)]
}

func (w *World) GetObjStateByKey(key string) *ObjState {
	w.mu.Lock()
	defer w.mu.Unlock()
	if w.objStates == nil {
		return nil
	}
	return w.objStates[key]
}

func (w *World) AllObjInstances(roomID int) []ObjState {
	w.mu.Lock()
	defer w.mu.Unlock()
	var out []ObjState
	for _, st := range w.objStates {
		if st.RoomID == roomID {
			out = append(out, *st)
		}
	}
	sort.Slice(out, func(i, j int) bool {
		if out[i].DefID != out[j].DefID {
			return out[i].DefID < out[j].DefID
		}
		return out[i].Index < out[j].Index
	})
	return out
}

func (w *World) FindObjInstances(roomID int, name string) []ObjState {
	w.mu.Lock()
	defer w.mu.Unlock()
	var out []ObjState
	lower := strings.ToLower(name)
	for _, st := range w.objStates {
		if st.RoomID != roomID {
			continue
		}
		if !wordMatchesObj(lower, st.DefID, st.Name, st.Aliases) {
			continue
		}
		out = append(out, ObjState{
			DefID:        st.DefID,
			Name:         st.Name,
			Aliases:      st.Aliases,
			Index:        st.Index,
			RoomID:       st.RoomID,
			HomeRoomID:   st.HomeRoomID,
			Dynamic:      st.Dynamic,
			Depleted:     st.Depleted,
			DepleteTimer: st.DepleteTimer,
			SharedMax:    st.SharedMax,
			SharedTimer:  st.SharedTimer,
			Quality:      st.Quality,
		})
	}
	sort.Slice(out, func(i, j int) bool {
		if out[i].DefID != out[j].DefID {
			return out[i].DefID < out[j].DefID
		}
		return out[i].Index < out[j].Index
	})
	return out
}

func wordMatchesObj(lower, defID, objName string, aliases []string) bool {
	if behavior.WordPrefixMatch(lower, objName) {
		return true
	}
	for _, alias := range aliases {
		if behavior.WordPrefixMatch(lower, alias) {
			return true
		}
	}
	inputWords := strings.Fields(strings.ToLower(lower))

	if strings.HasPrefix(strings.ToLower(defID), lower) || strings.HasPrefix(lower, strings.ToLower(defID)) {
		return true
	}
	for _, part := range strings.Split(defID, "_") {
		for _, iw := range inputWords {
			pl := strings.ToLower(part)
			if strings.HasPrefix(pl, iw) || strings.HasPrefix(iw, pl) {
				return true
			}
		}
	}
	return false
}

func (w *World) SetObjName(roomID int, defID string, name string) {
	w.mu.Lock()
	defer w.mu.Unlock()
	for _, st := range w.objStates {
		if st.HomeRoomID == roomID && st.DefID == defID {
			st.Name = name
		}
	}
}

func (w *World) SetObjAliases(roomID int, defID string, aliases []string) {
	w.mu.Lock()
	defer w.mu.Unlock()
	for _, st := range w.objStates {
		if st.HomeRoomID == roomID && st.DefID == defID {
			st.Aliases = aliases
		}
	}
}

func (w *World) SetObjWander(roomID int, defID string, rooms []int, interval float64) {
	w.mu.Lock()
	defer w.mu.Unlock()
	for _, st := range w.objStates {
		if st.HomeRoomID == roomID && st.DefID == defID {
			st.WanderRooms = rooms
			st.WanderInterval = interval
		}
	}
}

func (w *World) SetObjDepleteTimer(roomID int, defID string, max float64) {
	w.mu.Lock()
	defer w.mu.Unlock()
	for _, st := range w.objStates {
		if st.HomeRoomID == roomID && st.DefID == defID && st.SharedMax == 0 {
			st.SharedMax = max
			st.SharedTimer = int(max)
		}
	}
}

func (w *World) AllSharedObjStates() []*ObjState {
	w.mu.Lock()
	defer w.mu.Unlock()
	var out []*ObjState
	for _, st := range w.objStates {
		if st.SharedMax > 0 {
			out = append(out, st)
		}
	}
	return out
}

func (w *World) SetObjDepleted(roomID int, defID string, index int, delay float64) {
	w.mu.Lock()
	defer w.mu.Unlock()
	key := w.ObjStateKey(roomID, defID, index)
	if st, ok := w.objStates[key]; ok {
		st.Depleted = true
		st.DepleteTimer = delay
	}
}

func (w *World) FlushObjRespawns() []ObjState {
	w.mu.Lock()
	defer w.mu.Unlock()
	var out []ObjState
	for _, st := range w.objStates {
		if st.JustRespawned {
			out = append(out, *st)
			st.JustRespawned = false
		}
	}
	return out
}

func (w *World) TickObjWander() {
	w.mu.Lock()
	defer w.mu.Unlock()
	var moves []struct {
		st     *ObjState
		toRoom int
	}
	for _, st := range w.objStates {
		if len(st.WanderRooms) == 0 || st.WanderInterval <= 0 {
			continue
		}
		st.WanderCounter++
		if float64(st.WanderCounter) < st.WanderInterval {
			continue
		}
		st.WanderCounter = 0
		toRoom := st.WanderRooms[rand.Intn(len(st.WanderRooms))]
		if toRoom == st.RoomID {
			continue
		}
		// A wander_rooms entry may point at a room that was since deleted.
		// Moving there would strand the object in a nonexistent room, so
		// leave it where it is. (roomPathIndex is read under w.mu, which
		// this method already holds; LoadRoom would deadlock here.)
		if _, ok := w.roomPathIndex[toRoom]; !ok {
			continue
		}
		moves = append(moves, struct {
			st     *ObjState
			toRoom int
		}{st, toRoom})
	}
	for _, m := range moves {
		oldKey := w.ObjStateKey(m.st.RoomID, m.st.DefID, m.st.Index)
		fromRoom := m.st.RoomID
		newKey := w.ObjStateKey(m.toRoom, m.st.DefID, m.st.Index)
		if existing, ok := w.objStates[newKey]; ok && existing != m.st {
			log.Printf("skip wander of object %q index %d from room %d to %d: destination key %q is already occupied", m.st.DefID, m.st.Index, fromRoom, m.toRoom, newKey)
			continue
		}
		m.st.RoomID = m.toRoom
		delete(w.objStates, oldKey)
		w.objStates[newKey] = m.st
		w.objMoves = append(w.objMoves, ObjMove{
			DefID:    m.st.DefID,
			Name:     m.st.Name,
			FromRoom: fromRoom,
			ToRoom:   m.toRoom,
		})
	}
}

func (w *World) FlushObjMoves() []ObjMove {
	w.mu.Lock()
	defer w.mu.Unlock()
	out := w.objMoves
	w.objMoves = nil
	return out
}

func (w *World) tickObjStatesLocked() {
	for _, st := range w.objStates {
		if st.Depleted && st.DepleteTimer > 0 {
			st.DepleteTimer--
			if st.DepleteTimer <= 0 {
				st.Depleted = false
				st.JustRespawned = true
				if st.SharedMax > 0 {
					st.SharedTimer = int(st.SharedMax)
				}
			}
		}
	}
}