package v1

import (
	"net/http"
	"strconv"

	"github.com/gin-gonic/gin"
	"github.com/gochat/gochat/internal/service"
	applogger "github.com/gochat/gochat/pkg/logger"
	"github.com/gochat/gochat/pkg/response"
)

// CaptainConversationHandler handles Captain conversation-level AI auto-response.
// Reference: M12 PRD §Captain AI — Conversation Auto-Response (handoff mode)
//
// This handler exposes the CaptainConversationService, which generates AI
// responses for conversations bound to a Captain Assistant. When the AI
// determines a handoff is needed, the conversation is transferred to a human
// agent instead of sending an AI-generated reply.
type CaptainConversationHandler struct {
	svc *service.CaptainConversationService
}

// NewCaptainConversationHandler creates a new CaptainConversationHandler.
func NewCaptainConversationHandler(svc *service.CaptainConversationService) *CaptainConversationHandler {
	return &CaptainConversationHandler{svc: svc}
}

// BuildResponse triggers AI response generation for a conversation.
// The assistant must be bound to the conversation's inbox via CaptainInbox.
//
// POST /api/v1/accounts/:account_id/captain/conversations/:conversation_id/respond
func (h *CaptainConversationHandler) BuildResponse(c *gin.Context) {
	accountID, err := strconv.ParseUint(c.Param("account_id"), 10, 64)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, "invalid_account_id", "Invalid account ID")
		return
	}

	conversationID, err := strconv.ParseUint(c.Param("conversation_id"), 10, 64)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, "invalid_conversation_id", "Invalid conversation ID")
		return
	}

	var req struct {
		AssistantID uint `json:"assistant_id" binding:"required"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, "invalid_request", err.Error())
		return
	}

	msg, err := h.svc.BuildConversationResponseByAccount(c.Request.Context(), uint(accountID), uint(conversationID), req.AssistantID)
	if err != nil {
		applogger.L().Errorf("CaptainConversationHandler.BuildResponse: %v", err)
		response.AbortWithStatusError(c, http.StatusInternalServerError, "response_failed", "Failed to generate AI response")
		return
	}

	if msg == nil {
		response.OK(c, map[string]any{"status": "skipped", "message": "Conversation not eligible for AI response"})
		return
	}

	response.OK(c, map[string]any{"status": "sent", "message_id": msg.ID})
}