package app

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strconv"
	"strings"
)

// oneOSAssetVehicle contains only asset catalog fields from the OneOS vehicle
// page. Authorization only consumes fully enumerated caller-scoped snapshots
// when ONEOS_VEHICLE_QUERY_SCOPE is explicitly enabled.
type oneOSAssetVehicle struct {
	ID                        string `json:"id"`
	VIN                       string `json:"vin"`
	PlateNumber               string `json:"plateNumber"`
	VehicleType               string `json:"vehicleType"`
	Brand                     string `json:"brand"`
	BrandName                 string `json:"brandName"`
	Model                     string `json:"model"`
	ModelName                 string `json:"modelName"`
	ProvinceName              string `json:"provinceName"`
	CityName                  string `json:"cityName"`
	CustomerName              string `json:"customerName"`
	ProjectName               string `json:"projectName"`
	BusinessDepartment        string `json:"businessDepartment"`
	BusinessResponsiblePerson string `json:"businessResponsiblePerson"`
	OperationStatus           string `json:"operationStatus"`
	VehicleSource             string `json:"vehicleSource"`
}

func (v *oneOSAssetVehicle) UnmarshalJSON(raw []byte) error {
	type fields oneOSAssetVehicle
	var payload struct {
		fields
		ID json.RawMessage `json:"id"`
	}
	if err := json.Unmarshal(raw, &payload); err != nil {
		return err
	}
	*v = oneOSAssetVehicle(payload.fields)
	id, err := oneOSIDString(payload.ID)
	if err != nil {
		return err
	}
	v.ID = id
	return nil
}

type oneOSAssetPage struct {
	Records []oneOSAssetVehicle `json:"records"`
	Total   int64               `json:"total"`
	Current int64               `json:"current"`
	Size    int64               `json:"size"`
}

var errOneOSAssetQuery = errors.New("invalid OneOS asset query")

var oneOSAssetPageFilters = map[string]bool{
	"assetCategory": true, "vin": true, "plateNumber": true, "plateNumberList": true,
	"province": true, "city": true, "provinces": true, "vehicleType": true,
	"brand": true, "model": true, "customerName": true, "businessDept": true,
	"registeredOwnership": true, "contractCode": true, "operationOrgId": true,
	"vehicleSource": true, "rentalCompany": true, "operationStatus": true,
	"vehicleStatus": true, "onlineStatus": true, "licenseStatus": true,
	"packingLotId": true, "provinceName": true, "cityName": true,
	"commercialInsuranceStatus": true, "compulsoryInsuranceStatus": true,
	"projectName": true, "insuranceStatus": true,
}

const oneOSVehicleAssetCategory = "allOperating"

// VehicleAssetPage faithfully reads one bounded page of the OneOS vehicle
// catalog. It neither scans all pages nor turns records into permission grants.
func (c *oneOSProfileClient) VehicleAssetPage(ctx context.Context, token, clientID string, filters url.Values) (oneOSAssetPage, error) {
	return c.vehicleAssetPage(ctx, token, clientID, filters, 50)
}

// Larger pages are reserved for the server-side permission snapshot.
func (c *oneOSProfileClient) vehicleAssetPage(ctx context.Context, token, clientID string, filters url.Values, maxPageSize int64) (oneOSAssetPage, error) {
	if c == nil || !validOneOSLoginToken(token) || clientID == "" || clientID != c.passwordClientID {
		return oneOSAssetPage{}, errors.New("invalid OneOS credential")
	}
	query := url.Values{}
	pageNum, pageSize := int64(1), int64(10)
	if filters != nil {
		for key, values := range filters {
			if key == "pageNum" || key == "pageSize" {
				if len(values) != 1 || strings.TrimSpace(values[0]) == "" {
					return oneOSAssetPage{}, errOneOSAssetQuery
				}
				continue
			}
			if !oneOSAssetPageFilters[key] || len(values) == 0 || len(values) > 20 {
				return oneOSAssetPage{}, errOneOSAssetQuery
			}
			for _, value := range values {
				if strings.TrimSpace(value) == "" || len(value) > 128 || strings.ContainsAny(value, "\r\n") {
					return oneOSAssetPage{}, errOneOSAssetQuery
				}
				query.Add(key, value)
			}
		}
		if raw := filters.Get("pageNum"); raw != "" {
			parsed, err := strconv.ParseInt(raw, 10, 64)
			if err != nil || parsed < 1 || parsed > 1000000 || len(filters["pageNum"]) != 1 {
				return oneOSAssetPage{}, errOneOSAssetQuery
			}
			pageNum = parsed
		}
		if raw := filters.Get("pageSize"); raw != "" {
			parsed, err := strconv.ParseInt(raw, 10, 64)
			if err != nil || parsed < 1 || parsed > maxPageSize || len(filters["pageSize"]) != 1 {
				return oneOSAssetPage{}, errOneOSAssetQuery
			}
			pageSize = parsed
		}
	}
	if len(query["assetCategory"]) > 1 {
		return oneOSAssetPage{}, errOneOSAssetQuery
	}
	// Fixed business boundary; caller filters cannot select a different category.
	query.Set("assetCategory", oneOSVehicleAssetCategory)
	query.Set("pageNum", strconv.FormatInt(pageNum, 10))
	query.Set("pageSize", strconv.FormatInt(pageSize, 10))
	ctx, cancel := context.WithTimeout(ctx, c.requestTimeout)
	defer cancel()
	request, err := http.NewRequestWithContext(ctx, http.MethodGet, c.baseURL+"/asset/vehicle-info/page?"+query.Encode(), nil)
	if err != nil {
		return oneOSAssetPage{}, errors.New("invalid OneOS asset request")
	}
	request.Header.Set("Authorization", "Bearer "+token)
	request.Header.Set("ClientID", clientID)
	request.Header.Set("Accept", "application/json")
	response, err := c.client.Do(request)
	if err != nil {
		return oneOSAssetPage{}, errors.New("OneOS asset page unavailable")
	}
	defer response.Body.Close()
	if response.StatusCode != http.StatusOK {
		return oneOSAssetPage{}, fmt.Errorf("OneOS asset page rejected: HTTP %d", response.StatusCode)
	}
	raw, err := io.ReadAll(io.LimitReader(response.Body, (1<<20)+1))
	if err != nil || len(raw) > 1<<20 {
		return oneOSAssetPage{}, errors.New("OneOS asset page too large")
	}
	var envelope oneOSProfileEnvelope[oneOSAssetPage]
	if err := json.Unmarshal(raw, &envelope); err != nil || envelope.Code != 200 {
		return oneOSAssetPage{}, errors.New("invalid OneOS asset page response")
	}
	page := envelope.Data
	if page.Total < 0 || page.Current != pageNum || page.Size != pageSize || int64(len(page.Records)) > pageSize {
		return oneOSAssetPage{}, errors.New("invalid OneOS asset page metadata")
	}
	return page, nil
}