package modules

import (
	"encoding/base64"
	"fmt"
	"net/http"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/lineup/app-server/internal/wkapi"
)

// MessageModule handles message sending and syncing.
type MessageModule struct {
	wk *wkapi.Client
}

// NewMessageModule creates a new MessageModule.
func NewMessageModule(wk *wkapi.Client) *MessageModule {
	return &MessageModule{wk: wk}
}

// RegisterRoutes registers message routes.
func (m *MessageModule) RegisterRoutes(r *gin.Engine) {
	r.POST("/messages/send", m.handleSend)
	r.GET("/messages/sync", m.handleSync)
	r.POST("/messages/sync", m.handleSyncPost)
}

type sendMessageRequest struct {
	FromUID     string `json:"from_uid" binding:"required"`
	ChannelID   string `json:"channel_id" binding:"required"`
	ChannelType uint8  `json:"channel_type" binding:"required"`
	Payload     string `json:"payload" binding:"required"` // raw text, will be base64-encoded
}

func (m *MessageModule) handleSend(c *gin.Context) {
	var req sendMessageRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "参数错误: from_uid, channel_id, channel_type, payload必填"})
		return
	}

	// Base64-encode the payload for WuKongIM
	encoded := base64.StdEncoding.EncodeToString([]byte(req.Payload))

	resp, err := m.wk.SendMessage(wkapi.SendMessageRequest{
		FromUID:     req.FromUID,
		ChannelID:   req.ChannelID,
		ChannelType: req.ChannelType,
		ClientMsgNo: fmt.Sprintf("msg_%d", time.Now().UnixNano()),
		Payload:     encoded,
	})
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "发送消息失败: " + err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"message_id":  resp.MessageID,
		"message_seq": resp.MessageSeq,
	})
}

type syncMessagesRequest struct {
	ChannelID       string `form:"channel_id" binding:"required"`
	ChannelType     uint8  `form:"channel_type" binding:"required"`
	StartMessageSeq uint64 `form:"start_message_seq"`
	Limit           int    `form:"limit"`
}

func (m *MessageModule) handleSync(c *gin.Context) {
	var req syncMessagesRequest
	if err := c.ShouldBindQuery(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "参数错误: channel_id, channel_type必填"})
		return
	}
	m.doSync(c, req.ChannelID, req.ChannelType, req.StartMessageSeq, req.Limit, "")
}

type syncMessagesPostRequest struct {
	ChannelID       string `json:"channel_id" binding:"required"`
	ChannelType     uint8  `json:"channel_type" binding:"required"`
	LoginUID        string `json:"login_uid"`
	StartMessageSeq uint64 `json:"start_message_seq"`
	Limit           int    `json:"limit"`
}

func (m *MessageModule) handleSyncPost(c *gin.Context) {
	var req syncMessagesPostRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "参数错误: channel_id, channel_type必填"})
		return
	}
	m.doSync(c, req.ChannelID, req.ChannelType, req.StartMessageSeq, req.Limit, req.LoginUID)
}

func (m *MessageModule) doSync(c *gin.Context, channelID string, channelType uint8, startSeq uint64, limit int, loginUID string) {
	if limit <= 0 {
		limit = 20
	}

	resp, err := m.wk.SyncChannelMessages(wkapi.SyncChannelMessagesRequest{
		LoginUID:        loginUID,
		ChannelID:       channelID,
		ChannelType:     channelType,
		StartMessageSeq: startSeq,
		Limit:           limit,
		PullMode:        1,
	})
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "同步消息失败: " + err.Error()})
		return
	}

	// Decode base64 payloads for the response
	type msgItem struct {
		MessageID   uint64 `json:"message_id"`
		MessageSeq  uint64 `json:"message_seq"`
		FromUID     string `json:"from_uid"`
		ChannelID   string `json:"channel_id"`
		Payload     string `json:"payload"`
		Timestamp   int32  `json:"timestamp"`
	}
	messages := make([]msgItem, 0, len(resp.Messages))
	for _, m := range resp.Messages {
		decoded, _ := base64.StdEncoding.DecodeString(m.Payload)
		messages = append(messages, msgItem{
			MessageID:  m.MessageID,
			MessageSeq: m.MessageSeq,
			FromUID:    m.FromUID,
			ChannelID:  m.ChannelID,
			Payload:    string(decoded),
			Timestamp:  m.Timestamp,
		})
	}

	c.JSON(http.StatusOK, gin.H{
		"start_message_seq": resp.StartMessageSeq,
		"end_message_seq":   resp.EndMessageSeq,
		"more":              resp.More,
		"messages":          messages,
	})
}