// Package modules - 聊天系统模块
// 对齐GDD-29 聊天与信息传递系统设计
package modules

import (
	"context"
	"database/sql"
	"encoding/json"
	"time"

	"github.com/heroiclabs/nakama-common/runtime"
)

// RegisterChat 注册聊天相关 RPC。
func RegisterChat(initializer runtime.Initializer) error {
	rpcs := map[string]func(ctx context.Context, logger runtime.Logger, db *sql.DB, nk runtime.NakamaModule, payload string) (string, error){
		"ChatService/SendMessage":      sendMessage,
		"ChatService/GetMessages":      getMessages,
		"ChatService/GetChatChannels":  getChatChannels,
		"ChatService/JoinChannel":      joinChannel,
		"ChatService/LeaveChannel":     leaveChannel,
	}
	for path, fn := range rpcs {
		if err := initializer.RegisterRpc(path, fn); err != nil {
			return err
		}
	}
	return nil
}

type sendMessageReq struct {
	ChannelID string `json:"channel_id"` // channel_id 或 player_id（私聊）
	Content   string `json:"content"`
	MsgType   string `json:"msg_type"` // text/system/emote
}

type getMessagesReq struct {
	ChannelID string `json:"channel_id"`
	Limit     int32  `json:"limit"`
	Before    string `json:"before"` // 分页游标
}

type getChatChannelsReq struct {
	CharacterID string `json:"character_id"`
}

type joinChannelReq struct {
	ChannelID string `json:"channel_id"`
}

type leaveChannelReq struct {
	ChannelID string `json:"channel_id"`
}

type chatMessageData struct {
	MessageID   string    `json:"message_id"`
	SenderID    string    `json:"sender_id"`
	SenderName  string    `json:"sender_name"`
	SenderRace  string    `json:"sender_race"`
	ChannelID   string    `json:"channel_id"`
	ChannelType string    `json:"channel_type"` // world/region/guild/party/private/system
	Content     string    `json:"content"`
	MsgType     string    `json:"msg_type"` // text/system/emote
	Timestamp   time.Time `json:"timestamp"`
}

type chatChannelData struct {
	ChannelID   string `json:"channel_id"`
	ChannelType string `json:"channel_type"`
	Name        string `json:"name"`
	MemberCount int32  `json:"member_count"`
	IsMuted     bool   `json:"is_muted"`
}

// 频道配置
var channelConfig = map[string]chatChannelData{
	"world": {
		ChannelID: "world", ChannelType: "world", Name: "世界频道", MemberCount: 0,
	},
	"region_1": {
		ChannelID: "region_1", ChannelType: "region", Name: "凡界频道", MemberCount: 0,
	},
	"region_2": {
		ChannelID: "region_2", ChannelType: "region", Name: "灵界频道", MemberCount: 0,
	},
	"region_3": {
		ChannelID: "region_3", ChannelType: "region", Name: "道界频道", MemberCount: 0,
	},
	"region_4": {
		ChannelID: "region_4", ChannelType: "region", Name: "圣界频道", MemberCount: 0,
	},
}

func sendMessage(ctx context.Context, logger runtime.Logger, db *sql.DB, nk runtime.NakamaModule, payload string) (string, error) {
	traceID := newTraceID()
	uid := userIDFromCtx(ctx)
	if uid == "" {
		return errResp(1001, "missing token", traceID)
	}

	var req sendMessageReq
	if err := json.Unmarshal([]byte(payload), &req); err != nil {
		return errResp(2001, "invalid payload", traceID)
	}

	// 获取发送者信息
	var charID string
	var charName string
	var raceID string
	err := hhdbPool.QueryRow(ctx, `
		SELECT id, name, race_id FROM characters WHERE player_id = $1 AND status = 'active'
		ORDER BY created_at DESC LIMIT 1
	`, uid).Scan(&charID, &charName, &raceID)
	if err != nil {
		return errResp(4002, "character not found", traceID)
	}

	// 检查消息长度
	if len(req.Content) > 500 {
		return errResp(8801, "message too long", traceID)
	}

	// 发送消息（简化版，实际应使用Nakama实时多人游戏API）
	message := chatMessageData{
		MessageID:   genUUID(),
		SenderID:    charID,
		SenderName:  charName,
		SenderRace:  raceID,
		ChannelID:   req.ChannelID,
		ChannelType: getChannelType(req.ChannelID),
		Content:     req.Content,
		MsgType:     req.MsgType,
		Timestamp:   time.Now(),
	}

	logger.Info("Chat message: sender=%s channel=%s content=%s", charName, req.ChannelID, req.Content)

	return okResp(message, traceID)
}

func getMessages(ctx context.Context, logger runtime.Logger, db *sql.DB, nk runtime.NakamaModule, payload string) (string, error) {
	traceID := newTraceID()
	uid := userIDFromCtx(ctx)
	if uid == "" {
		return errResp(1001, "missing token", traceID)
	}

	var req getMessagesReq
	if err := json.Unmarshal([]byte(payload), &req); err != nil {
		return errResp(2001, "invalid payload", traceID)
	}

	if req.Limit < 1 || req.Limit > 100 {
		req.Limit = 50
	}

	// 返回空消息列表（实际应从数据库/缓存读取）
	return okResp(map[string]interface{}{
		"channel_id": req.ChannelID,
		"messages":   []chatMessageData{},
		"count":      0,
		"has_more":   false,
	}, traceID)
}

func getChatChannels(ctx context.Context, logger runtime.Logger, db *sql.DB, nk runtime.NakamaModule, payload string) (string, error) {
	traceID := newTraceID()
	uid := userIDFromCtx(ctx)
	if uid == "" {
		return errResp(1001, "missing token", traceID)
	}

	var req getChatChannelsReq
	if err := json.Unmarshal([]byte(payload), &req); err != nil {
		return errResp(2001, "invalid payload", traceID)
	}

	// 返回可用频道列表
	var channels []chatChannelData
	for _, ch := range channelConfig {
		channels = append(channels, ch)
	}

	return okResp(map[string]interface{}{
		"channels": channels,
		"count":    len(channels),
	}, traceID)
}

func joinChannel(ctx context.Context, logger runtime.Logger, db *sql.DB, nk runtime.NakamaModule, payload string) (string, error) {
	traceID := newTraceID()
	uid := userIDFromCtx(ctx)
	if uid == "" {
		return errResp(1001, "missing token", traceID)
	}

	var req joinChannelReq
	if err := json.Unmarshal([]byte(payload), &req); err != nil {
		return errResp(2001, "invalid payload", traceID)
	}

	// 加入频道（简化版）
	logger.Info("Join channel: channel=%s", req.ChannelID)

	return okResp(map[string]interface{}{
		"success":    true,
		"channel_id": req.ChannelID,
		"message":    "已加入频道",
	}, traceID)
}

func leaveChannel(ctx context.Context, logger runtime.Logger, db *sql.DB, nk runtime.NakamaModule, payload string) (string, error) {
	traceID := newTraceID()
	uid := userIDFromCtx(ctx)
	if uid == "" {
		return errResp(1001, "missing token", traceID)
	}

	var req leaveChannelReq
	if err := json.Unmarshal([]byte(payload), &req); err != nil {
		return errResp(2001, "invalid payload", traceID)
	}

	// 离开频道（简化版）
	logger.Info("Leave channel: channel=%s", req.ChannelID)

	return okResp(map[string]interface{}{
		"success":    true,
		"channel_id": req.ChannelID,
		"message":    "已离开频道",
	}, traceID)
}

// 辅助函数
func getChannelType(channelID string) string {
	if channelID == "world" {
		return "world"
	}
	if len(channelID) > 6 && channelID[:6] == "region" {
		return "region"
	}
	return "other"
}