package rpc

import (
	"blazing/cool"
	"blazing/logic/service/fight/pvpwire"
	"context"
	"encoding/json"
	"fmt"
	"sync"
	"time"
)

const (
	pvpMatchQueueTTL      = 12 * time.Second
	pvpMatchBanPickSecond = 45
)

type PVPMatchJoinPayload struct {
	RuntimeServerID uint32   `json:"runtimeServerId"`
	UserID          uint32   `json:"userId"`
	Nick            string   `json:"nick"`
	FightMode       uint32   `json:"fightMode"`
	Status          uint32   `json:"status"`
	CatchTimes      []uint32 `json:"catchTimes"`
}

type pvpMatchCoordinator struct {
	mu       sync.Mutex
	queues   map[uint32][]pvpwire.QueuePlayerSnapshot
	lastSeen map[uint32]time.Time
}

var defaultPVPMatchCoordinator = &pvpMatchCoordinator{
	queues:   make(map[uint32][]pvpwire.QueuePlayerSnapshot),
	lastSeen: make(map[uint32]time.Time),
}

func DefaultPVPMatchCoordinator() *pvpMatchCoordinator {
	return defaultPVPMatchCoordinator
}

func (m *pvpMatchCoordinator) JoinOrUpdate(payload PVPMatchJoinPayload) error {
	if payload.UserID == 0 || payload.RuntimeServerID == 0 || payload.FightMode == 0 {
		return fmt.Errorf("invalid pvp match payload: uid=%d server=%d mode=%d", payload.UserID, payload.RuntimeServerID, payload.FightMode)
	}

	now := time.Now()
	player := pvpwire.QueuePlayerSnapshot{
		RuntimeServerID: payload.RuntimeServerID,
		UserID:          payload.UserID,
		Nick:            payload.Nick,
		FightMode:       payload.FightMode,
		Status:          payload.Status,
		JoinedAtUnix:    now.Unix(),
		CatchTimes:      append([]uint32(nil), payload.CatchTimes...),
	}

	var match *pvpwire.MatchFoundPayload

	m.mu.Lock()
	m.pruneExpiredLocked(now)
	m.removeUserLocked(payload.UserID)
	m.lastSeen[payload.UserID] = now

	queue := m.queues[payload.FightMode]
	if len(queue) > 0 {
		host := queue[0]
		queue = queue[1:]
		m.queues[payload.FightMode] = queue
		delete(m.lastSeen, host.UserID)
		delete(m.lastSeen, payload.UserID)

		result := pvpwire.MatchFoundPayload{
			SessionID:      buildPVPMatchSessionID(host.UserID, payload.UserID),
			Stage:          pvpwire.StageBanPick,
			Host:           host,
			Guest:          player,
			BanPickTimeout: pvpMatchBanPickSecond,
		}
		match = &result
	} else {
		m.queues[payload.FightMode] = append(queue, player)
	}
	m.mu.Unlock()

	if match == nil {
		return nil
	}
	if err := publishPVPMatchMessage(pvpwire.ServerTopic(match.Host.RuntimeServerID), pvpwire.MessageTypeMatchFound, *match); err != nil {
		return err
	}
	if match.Guest.RuntimeServerID != match.Host.RuntimeServerID {
		if err := publishPVPMatchMessage(pvpwire.ServerTopic(match.Guest.RuntimeServerID), pvpwire.MessageTypeMatchFound, *match); err != nil {
			return err
		}
	}
	return nil
}

func (m *pvpMatchCoordinator) Cancel(userID uint32) {
	if userID == 0 {
		return
	}
	m.mu.Lock()
	defer m.mu.Unlock()

	delete(m.lastSeen, userID)
	m.removeUserLocked(userID)
}

func (m *pvpMatchCoordinator) pruneExpiredLocked(now time.Time) {
	for mode, queue := range m.queues {
		next := make([]pvpwire.QueuePlayerSnapshot, 0, len(queue))
		for _, queued := range queue {
			last := m.lastSeen[queued.UserID]
			if last.IsZero() || now.Sub(last) > pvpMatchQueueTTL {
				delete(m.lastSeen, queued.UserID)
				continue
			}
			next = append(next, queued)
		}
		m.queues[mode] = next
	}
}

func (m *pvpMatchCoordinator) removeUserLocked(userID uint32) {
	for mode, queue := range m.queues {
		next := make([]pvpwire.QueuePlayerSnapshot, 0, len(queue))
		for _, queued := range queue {
			if queued.UserID == userID {
				continue
			}
			next = append(next, queued)
		}
		m.queues[mode] = next
	}
}

func publishPVPMatchMessage(topic, msgType string, body any) error {
	payload, err := json.Marshal(body)
	if err != nil {
		return err
	}
	envelope, err := json.Marshal(pvpwire.Envelope{
		Type: msgType,
		Body: payload,
	})
	if err != nil {
		return err
	}
	conn, err := cool.Redis.Conn(context.Background())
	if err != nil {
		return err
	}
	defer conn.Close(context.Background())

	_, err = conn.Do(context.Background(), "publish", topic, envelope)
	return err
}

func buildPVPMatchSessionID(hostUserID, guestUserID uint32) string {
	return fmt.Sprintf("xsvr-%d-%d-%d", hostUserID, guestUserID, time.Now().UnixNano())
}