package httpapi

import (
	"encoding/json"
	"errors"
	"io"
	"log"
	"net/http"

	"github.com/gin-gonic/gin"

	"git.apinb.com/ops/license/internal/dashboard"
	"git.apinb.com/ops/license/internal/issuance"
	"git.apinb.com/ops/license/internal/subject"
)

type pagination struct {
	Page     int   `json:"page"`
	PageSize int   `json:"page_size"`
	Total    int64 `json:"total"`
}

func writeData(c *gin.Context, status int, data any) {
	c.JSON(status, gin.H{"data": data})
}

func writePage(c *gin.Context, data any, page, pageSize int, total int64) {
	c.JSON(http.StatusOK, gin.H{
		"data": data,
		"pagination": pagination{
			Page:     page,
			PageSize: pageSize,
			Total:    total,
		},
	})
}

func writeBadRequest(c *gin.Context) {
	c.JSON(http.StatusBadRequest, gin.H{"code": "bad_request", "message": "请求格式不正确"})
}

func writeError(c *gin.Context, err error) {
	status := http.StatusInternalServerError
	code := "internal_error"
	message := "服务器内部错误"

	switch {
	case errors.Is(err, subject.ErrNotFound):
		status, code, message = http.StatusNotFound, "subject_not_found", "授权对象不存在"
	case errors.Is(err, issuance.ErrNotFound):
		status, code, message = http.StatusNotFound, "licence_not_found", "签发记录不存在"
	case errors.Is(err, subject.ErrDuplicate):
		status, code, message = http.StatusConflict, "subject_duplicate", "授权对象已存在"
	case errors.Is(err, subject.ErrHasLicences):
		status, code, message = http.StatusConflict, "subject_has_licences", "该授权对象已有签发记录，不能修改或删除"
	case errors.Is(err, subject.ErrInvalidInput):
		status, code, message = http.StatusUnprocessableEntity, "invalid_subject", "授权对象字段不合法"
	case errors.Is(err, issuance.ErrInvalidDates):
		status, code, message = http.StatusUnprocessableEntity, "invalid_licence_dates", "许可证日期不合法"
	case errors.Is(err, issuance.ErrInvalidQuota):
		status, code, message = http.StatusUnprocessableEntity, "invalid_licence_quota", "许可证配额不合法"
	case errors.Is(err, issuance.ErrPreviousMismatch):
		status, code, message = http.StatusUnprocessableEntity, "previous_licence_mismatch", "续期来源与授权对象不匹配"
	case errors.Is(err, issuance.ErrInvalidInput), errors.Is(err, dashboard.ErrInvalidInput):
		status, code, message = http.StatusUnprocessableEntity, "invalid_issuance", "签发参数不合法"
	}

	if status == http.StatusInternalServerError {
		log.Printf("HTTP internal error: %v", err)
	}
	c.JSON(status, gin.H{"code": code, "message": message})
}

func decodeJSON(c *gin.Context, destination any) error {
	decoder := json.NewDecoder(c.Request.Body)
	decoder.DisallowUnknownFields()
	if err := decoder.Decode(destination); err != nil {
		return err
	}
	var trailing any
	if err := decoder.Decode(&trailing); !errors.Is(err, io.EOF) {
		if err == nil {
			return errors.New("JSON 包含多个顶层值")
		}
		return err
	}
	return nil
}