// queue.go
package main

import (
	"encoding/json"
	"log"
	"sync"
	"time"
	"os"
)

type WaitingGame struct {
	Pin       string `json:"pin"`
	HostID    string `json:"host_id"`
	Required  int    `json:"required"`
	CreatedAt int64  `json:"created_at"`
}

type SlotManager struct {
	mu        sync.Mutex
	capacity  int
	available int
	waiting   []WaitingGame
	active    map[string]int
	savePath  string
}

func NewSlotManager(cap int, savePath string) *SlotManager {
	return &SlotManager{capacity: cap, available: cap, waiting: make([]WaitingGame, 0), active: make(map[string]int), savePath: savePath}
}

func (sm *SlotManager) Load() {
	data, err := os.ReadFile(sm.savePath)
	if err != nil { return }
	var state struct {
		Available int           `json:"available"`
		Waiting   []WaitingGame `json:"waiting"`
		Active    map[string]int `json:"active"`
	}
	if json.Unmarshal(data, &state) == nil {
		sm.mu.Lock()
		sm.available = state.Available
		sm.waiting = state.Waiting
		sm.active = state.Active
		sm.mu.Unlock()
		Info("Queue State Restored: Avail=%d, Waiting=%d, Active=%d", sm.available, len(sm.waiting), len(sm.active))
	}
}

func (sm *SlotManager) Save() {
	sm.mu.Lock()
	defer sm.mu.Unlock()
	state := struct {
		Available int           `json:"available"`
		Waiting   []WaitingGame `json:"waiting"`
		Active    map[string]int `json:"active"`
	}{sm.available, sm.waiting, sm.active}
	data, _ := json.Marshal(state)
	os.WriteFile(sm.savePath, data, 0644)
}

func (sm *SlotManager) PersistLoop(interval time.Duration) {
	ticker := time.NewTicker(interval)
	for range ticker.C { sm.Save() }
}

// RequestSlots : appelé par Host (HTTP) quand il clique "Start"
func (sm *SlotManager) RequestSlots(pin, hostID string, required int) (bool, chan struct{}) {
	sm.mu.Lock()
	defer sm.mu.Unlock()

	if sm.available >= required {
		sm.available -= required
		sm.active[pin] = required
		sm.Save()
		return true, nil
	}

	ch := make(chan struct{}, 1)
	wg := WaitingGame{Pin: pin, HostID: hostID, Required: required, CreatedAt: time.Now().Unix()}
	sm.waiting = append(sm.waiting, wg)
	sm.Save()
	return false, ch
}

// ReleaseSlots : appelé quand partie finie (Game Engine)
func (sm *SlotManager) ReleaseSlots(pin string, count int) {
	sm.mu.Lock()
	defer sm.mu.Unlock()

	reserved := sm.active[pin]
	if reserved == 0 { return }
	releaseCount := min(count, reserved)
	sm.available += releaseCount

	if releaseCount >= reserved {
		delete(sm.active, pin)
	} else {
		sm.active[pin] = reserved - releaseCount
	}

	// Traiter file d'attente
	newWaiting := make([]WaitingGame, 0, len(sm.waiting))
	for _, wg := range sm.waiting {
		if sm.available >= wg.Required {
			sm.available -= wg.Required
			sm.active[wg.Pin] = wg.Required
			// NOTIFIER LE GAME ENGINE (via fonction globale)
			go notifyQueueReady(wg.Pin) // Goroutine pour ne pas bloquer le lock
		} else {
			newWaiting = append(newWaiting, wg)
		}
	}
	sm.waiting = newWaiting
	sm.Save()
}

func (sm *SlotManager) GetQueuePosition(pin string) int {
	sm.mu.Lock()
	defer sm.mu.Unlock()
	for i, wg := range sm.waiting {
		if wg.Pin == pin { return i + 1 }
	}
	return -1
}

// notifyQueueReady est appelé par Queue Manager quand des slots se libèrent
// Elle doit déclencher le démarrage de la partie dans game.go
func notifyQueueReady(pin string) {
	Info("Queue Slot Granted -> Starting Game: %s", pin)
	// Appelle la fonction de game.go (package main)
	StartGameLoop(hub, store, pin)
}