package handler

import (
	"errors"
	"net/http"
	"strings"

	"github.com/gin-gonic/gin"

	"xly/server/internal/model"
	"xly/server/internal/service"
)

// HTTPHandler 负责注册 HTTP 路由。
// 控制层只做参数校验和响应包装，不承担上游调用逻辑。
type HTTPHandler struct {
	ai *service.AIService
}

// NewHTTPHandler 创建 HTTP 控制器。
func NewHTTPHandler(ai *service.AIService) *HTTPHandler {
	return &HTTPHandler{ai: ai}
}

// Register 将接口注册到 Gin 路由树。
func (h *HTTPHandler) Register(router gin.IRouter) {
	router.GET("/healthz", h.healthz)
	router.GET("/api/v1/ai/status", h.aiStatus)
	router.POST("/api/v1/ai/interpret", h.aiInterpret)
}

func (h *HTTPHandler) healthz(ctx *gin.Context) {
	ctx.JSON(http.StatusOK, model.APIResponse[map[string]string]{
		Data: &map[string]string{
			"status": "ok",
		},
		Message: "service is healthy",
	})
}

func (h *HTTPHandler) aiStatus(ctx *gin.Context) {
	status := h.ai.Status()
	ctx.JSON(http.StatusOK, model.APIResponse[model.AIStatusResponse]{
		Data:    &status,
		Message: "ok",
	})
}

func (h *HTTPHandler) aiInterpret(ctx *gin.Context) {
	var request model.InterpretRequest
	if err := ctx.ShouldBindJSON(&request); err != nil {
		ctx.JSON(http.StatusBadRequest, model.APIResponse[model.InterpretResponse]{
			Message: "请求体无效，请检查解卦上下文是否完整。",
		})
		return
	}

	request.Question = strings.TrimSpace(request.Question)
	if request.Question == "" {
		ctx.JSON(http.StatusBadRequest, model.APIResponse[model.InterpretResponse]{
			Message: "所问之事不能为空。",
		})
		return
	}

	content, err := h.ai.Interpret(ctx.Request.Context(), request)
	if err != nil {
		statusCode := http.StatusBadGateway
		message := "AI 解卦失败。"

		switch {
		case errors.Is(err, service.ErrAIUnavailable):
			statusCode = http.StatusServiceUnavailable
			message = "后端 AI 服务尚未完成配置。"
		default:
			message = err.Error()
		}

		ctx.JSON(statusCode, model.APIResponse[model.InterpretResponse]{
			Message: message,
		})
		return
	}

	response := model.InterpretResponse{Content: content}
	ctx.JSON(http.StatusOK, model.APIResponse[model.InterpretResponse]{
		Data:    &response,
		Message: "ok",
	})
}