package handler

import (
	"strconv"

	"health-ai/internal/api/middleware"
	"health-ai/internal/service"
	"health-ai/pkg/response"

	"github.com/gin-gonic/gin"
)

type ConversationHandler struct {
	convService *service.ConversationService
}

func NewConversationHandler() *ConversationHandler {
	return &ConversationHandler{
		convService: service.NewConversationService(),
	}
}

// GetConversations 获取对话列表
// @Summary 获取对话列表
// @Tags AI对话
// @Accept json
// @Produce json
// @Param Authorization header string true "Bearer Token"
// @Success 200 {object} response.Response{data=[]service.ConversationResponse}
// @Router /api/conversations [get]
func (h *ConversationHandler) GetConversations(c *gin.Context) {
	userID := middleware.GetUserID(c)
	convs, err := h.convService.GetConversations(userID)
	if err != nil {
		response.Error(c, 500, err.Error())
		return
	}
	response.Success(c, convs)
}

// CreateConversation 创建新对话
// @Summary 创建新对话
// @Tags AI对话
// @Accept json
// @Produce json
// @Param Authorization header string true "Bearer Token"
// @Param request body service.CreateConversationRequest true "对话标题（可选）"
// @Success 200 {object} response.Response{data=service.ConversationResponse}
// @Router /api/conversations [post]
func (h *ConversationHandler) CreateConversation(c *gin.Context) {
	userID := middleware.GetUserID(c)
	var req service.CreateConversationRequest
	c.ShouldBindJSON(&req)

	conv, err := h.convService.CreateConversation(userID, req.Title)
	if err != nil {
		response.Error(c, 500, err.Error())
		return
	}
	response.Success(c, conv)
}

// GetConversation 获取对话详情
// @Summary 获取对话详情（含消息历史）
// @Tags AI对话
// @Accept json
// @Produce json
// @Param Authorization header string true "Bearer Token"
// @Param id path int true "对话ID"
// @Success 200 {object} response.Response{data=service.ConversationResponse}
// @Router /api/conversations/{id} [get]
func (h *ConversationHandler) GetConversation(c *gin.Context) {
	userID := middleware.GetUserID(c)
	convID, err := strconv.ParseUint(c.Param("id"), 10, 32)
	if err != nil {
		response.BadRequest(c, "无效的对话ID")
		return
	}

	conv, err := h.convService.GetConversation(userID, uint(convID))
	if err != nil {
		response.Error(c, 404, err.Error())
		return
	}
	response.Success(c, conv)
}

// DeleteConversation 删除对话
// @Summary 删除对话
// @Tags AI对话
// @Accept json
// @Produce json
// @Param Authorization header string true "Bearer Token"
// @Param id path int true "对话ID"
// @Success 200 {object} response.Response
// @Router /api/conversations/{id} [delete]
func (h *ConversationHandler) DeleteConversation(c *gin.Context) {
	userID := middleware.GetUserID(c)
	convID, err := strconv.ParseUint(c.Param("id"), 10, 32)
	if err != nil {
		response.BadRequest(c, "无效的对话ID")
		return
	}

	if err := h.convService.DeleteConversation(userID, uint(convID)); err != nil {
		response.Error(c, 400, err.Error())
		return
	}
	response.SuccessWithMessage(c, "对话已删除", nil)
}

// SendMessage 发送消息
// @Summary 发送消息并获取AI回复
// @Tags AI对话
// @Accept json
// @Produce json
// @Param Authorization header string true "Bearer Token"
// @Param id path int true "对话ID"
// @Param request body service.SendMessageRequest true "消息内容"
// @Success 200 {object} response.Response{data=service.MessageResponse}
// @Router /api/conversations/{id}/messages [post]
func (h *ConversationHandler) SendMessage(c *gin.Context) {
	userID := middleware.GetUserID(c)
	convID, err := strconv.ParseUint(c.Param("id"), 10, 32)
	if err != nil {
		response.BadRequest(c, "无效的对话ID")
		return
	}

	var req service.SendMessageRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, "请输入消息内容")
		return
	}

	if req.Content == "" {
		response.BadRequest(c, "消息内容不能为空")
		return
	}

	reply, err := h.convService.SendMessage(c.Request.Context(), userID, uint(convID), req.Content)
	if err != nil {
		response.Error(c, 500, "AI回复失败: "+err.Error())
		return
	}

	response.Success(c, reply)
}

// SendMessageStream 流式发送消息（SSE）
// @Summary 流式发送消息
// @Tags AI对话
// @Accept json
// @Produce text/event-stream
// @Param Authorization header string true "Bearer Token"
// @Param id path int true "对话ID"
// @Param request body service.SendMessageRequest true "消息内容"
// @Router /api/conversations/{id}/messages/stream [post]
func (h *ConversationHandler) SendMessageStream(c *gin.Context) {
	userID := middleware.GetUserID(c)
	convID, err := strconv.ParseUint(c.Param("id"), 10, 32)
	if err != nil {
		response.BadRequest(c, "无效的对话ID")
		return
	}

	var req service.SendMessageRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, "请输入消息内容")
		return
	}

	// 设置 SSE 响应头
	c.Header("Content-Type", "text/event-stream")
	c.Header("Cache-Control", "no-cache")
	c.Header("Connection", "keep-alive")

	err = h.convService.SendMessageStream(c.Request.Context(), userID, uint(convID), req.Content, c.Writer)
	if err != nil {
		c.SSEvent("error", err.Error())
	}
	c.SSEvent("done", "")
}