package device

import (
	stdcontext "context"
	"encoding/json"
	"errors"
	"io"
	"net/http"
	"strconv"
	"strings"

	"github.com/gin-gonic/gin"
	"github.com/go-admin-team/go-admin-core/sdk/pkg"
	"gorm.io/gorm"
)

type Handler struct {
	DB *gorm.DB
}

func (handler Handler) List(context *gin.Context) {
	request, err := parseListRequest(context)
	if err != nil {
		writeError(context, err)
		return
	}
	db, err := handler.database(context)
	if err != nil {
		writeError(context, internalError(err))
		return
	}
	response, err := NewService(db).List(context.Request.Context(), request)
	if err != nil {
		writeError(context, err)
		return
	}
	context.JSON(http.StatusOK, gin.H{"code": http.StatusOK, "data": response})
}

func (handler Handler) Register(context *gin.Context) {
	request, err := decodeRegisterRequest(context)
	if err != nil {
		writeError(context, invalidRequest("请求 JSON 无效"))
		return
	}
	db, err := handler.database(context)
	if err != nil {
		writeError(context, internalError(err))
		return
	}
	response, err := NewService(db).Register(context.Request.Context(), request, bearerToken(context.GetHeader("Authorization")))
	if err != nil {
		writeError(context, err)
		return
	}
	context.Header("Cache-Control", "no-store")
	context.JSON(http.StatusOK, gin.H{"data": response})
}

func (handler Handler) Heartbeat(context *gin.Context) {
	var request HeartbeatRequest
	if err := decodeJSON(context, &request); err != nil {
		writeError(context, invalidRequest("请求 JSON 无效"))
		return
	}
	db, err := handler.database(context)
	if err != nil {
		writeError(context, internalError(err))
		return
	}
	response, err := NewService(db).Heartbeat(context.Request.Context(), request, bearerToken(context.GetHeader("Authorization")))
	if err != nil {
		writeError(context, err)
		return
	}
	context.JSON(http.StatusOK, gin.H{"data": response})
}

func (handler Handler) Disable(context *gin.Context) {
	handler.adminAction(context, (*Service).Disable)
}

func (handler Handler) RevokeToken(context *gin.Context) {
	handler.adminAction(context, (*Service).RevokeToken)
}

func (handler Handler) adminAction(context *gin.Context, action func(*Service, stdcontext.Context, uint64) error) {
	deviceID, err := strconv.ParseUint(context.Param("deviceId"), 10, 64)
	if err != nil || deviceID == 0 {
		writeError(context, invalidRequest("deviceId 无效"))
		return
	}
	db, err := handler.database(context)
	if err != nil {
		writeError(context, internalError(err))
		return
	}
	if err := action(NewService(db), context.Request.Context(), deviceID); err != nil {
		writeError(context, err)
		return
	}
	context.JSON(http.StatusOK, gin.H{"code": http.StatusOK, "data": gin.H{"deviceId": deviceID}})
}

func (handler Handler) database(context *gin.Context) (*gorm.DB, error) {
	if handler.DB != nil {
		return handler.DB, nil
	}
	return pkg.GetOrm(context)
}

func decodeRegisterRequest(context *gin.Context) (RegisterRequest, error) {
	var request RegisterRequest
	if err := decodeJSON(context, &request); err != nil {
		return RegisterRequest{}, err
	}
	return request, nil
}

func decodeJSON(context *gin.Context, destination any) error {
	context.Request.Body = http.MaxBytesReader(context.Writer, context.Request.Body, 64<<10)
	decoder := json.NewDecoder(context.Request.Body)
	decoder.DisallowUnknownFields()
	if err := decoder.Decode(destination); err != nil {
		return err
	}
	if err := decoder.Decode(&struct{}{}); !errors.Is(err, io.EOF) {
		return errors.New("request body must contain one JSON object")
	}
	return nil
}

func bearerToken(header string) string {
	parts := strings.Fields(header)
	if len(parts) != 2 || !strings.EqualFold(parts[0], "Bearer") {
		return ""
	}
	return parts[1]
}

func writeError(context *gin.Context, err error) {
	var serviceError *ServiceError
	if !errors.As(err, &serviceError) {
		serviceError = internalError(err).(*ServiceError)
	}
	status := http.StatusInternalServerError
	switch serviceError.Code {
	case CodeInvalidRequest:
		status = http.StatusUnprocessableEntity
	case CodeInstallIDConflict:
		status = http.StatusConflict
	case CodeTokenInvalid:
		status = http.StatusUnauthorized
	case CodeDeviceDisabled:
		status = http.StatusForbidden
	case CodeDeviceTaskMismatch:
		status = http.StatusConflict
	case CodeDeviceNotFound:
		status = http.StatusNotFound
	}
	context.JSON(status, gin.H{
		"code": serviceError.Code, "message": serviceError.Message, "retryable": serviceError.Retryable,
	})
}