package history

import (
	"compress/gzip"
	"context"
	"database/sql"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"strconv"
	"strings"
	"time"
)

type Queryer interface {
	QueryContext(context.Context, string, ...any) (*sql.Rows, error)
}

type RawFrameQuery struct {
	Protocol       string
	VehicleKey     string
	VIN            string
	Phone          string
	DeviceID       string
	MessageID      string
	OrderBy        string
	IncludeFields  bool
	IncludePayload bool
	IncludeTotal   bool
	ParsedFields   []string
	DateFrom       string
	DateTo         string
	Limit          int
	Offset         int
}

type RawFrameRow struct {
	TS             string          `json:"ts"`
	FrameID        string          `json:"frame_id"`
	EventID        string          `json:"event_id"`
	MessageID      int64           `json:"message_id"`
	MessageIDHex   string          `json:"message_id_hex"`
	EventTime      string          `json:"event_time"`
	ReceivedAt     string          `json:"received_at"`
	RawSizeBytes   int64           `json:"raw_size_bytes"`
	RawHex         string          `json:"raw_hex,omitempty"`
	RawText        string          `json:"raw_text,omitempty"`
	ParsedFields   json.RawMessage `json:"parsed_fields,omitempty"`
	ParseStatus    string          `json:"parse_status"`
	ParseError     string          `json:"parse_error,omitempty"`
	SourceEndpoint string          `json:"source_endpoint"`
	Protocol       string          `json:"protocol"`
	VehicleKey     string          `json:"vehicle_key"`
	VIN            string          `json:"vin"`
	Phone          string          `json:"phone,omitempty"`
	DeviceID       string          `json:"device_id,omitempty"`
}

type LocationQuery struct {
	Protocol     string
	VIN          string
	IncludeTotal bool
	DateFrom     string
	DateTo       string
	Limit        int
	Offset       int
}

type LocationRow struct {
	TS             string   `json:"ts"`
	EventID        string   `json:"event_id"`
	ReceivedAt     string   `json:"received_at"`
	Longitude      float64  `json:"longitude"`
	Latitude       float64  `json:"latitude"`
	AltitudeM      *float64 `json:"altitude_m,omitempty"`
	SpeedKMH       *float64 `json:"speed_kmh,omitempty"`
	DirectionDeg   *int64   `json:"direction_deg,omitempty"`
	AlarmFlag      *int64   `json:"alarm_flag,omitempty"`
	StatusFlag     *int64   `json:"status_flag,omitempty"`
	TotalMileageKM *float64 `json:"total_mileage_km,omitempty"`
	Protocol       string   `json:"protocol"`
	VIN            string   `json:"vin"`
}

type rawFrameQueryRequest struct {
	Protocol       string   `json:"protocol"`
	VehicleKey     string   `json:"vehicleKey"`
	VehicleKeyAlt  string   `json:"vehicle_key"`
	VIN            string   `json:"vin"`
	Phone          string   `json:"phone"`
	DeviceID       string   `json:"deviceId"`
	DeviceIDAlt    string   `json:"device_id"`
	MessageID      string   `json:"messageId"`
	MessageIDAlt   string   `json:"message_id"`
	OrderBy        string   `json:"orderBy"`
	OrderByAlt     string   `json:"order_by"`
	IncludeFields  bool     `json:"includeFields"`
	IncludePayload bool     `json:"includePayload"`
	IncludeTotal   bool     `json:"includeTotal"`
	Fields         []string `json:"fields"`
	ParsedFields   []string `json:"parsedFields"`
	DateFrom       string   `json:"dateFrom"`
	DateFromAlt    string   `json:"date_from"`
	DateTo         string   `json:"dateTo"`
	DateToAlt      string   `json:"date_to"`
	Limit          int      `json:"limit"`
	Offset         int      `json:"offset"`
}

type RawFrameRepository struct {
	db       Queryer
	database string
}

func NewRawFrameRepository(db Queryer, database string) *RawFrameRepository {
	if db == nil {
		panic("raw frame query db must not be nil")
	}
	database = strings.TrimSpace(database)
	if database != "" && !safeIdentifier(database) {
		database = ""
	}
	return &RawFrameRepository{db: db, database: database}
}

type LocationRepository struct {
	db       Queryer
	database string
}

func NewLocationRepository(db Queryer, database string) *LocationRepository {
	if db == nil {
		panic("location query db must not be nil")
	}
	database = strings.TrimSpace(database)
	if database != "" && !safeIdentifier(database) {
		database = ""
	}
	return &LocationRepository{db: db, database: database}
}

func (r *RawFrameRepository) Query(ctx context.Context, query RawFrameQuery) ([]RawFrameRow, error) {
	query = normalizeRawFrameQuery(query)
	sqlText, args := buildRawFrameSQL(r.tableName(query), query)
	rows, err := r.db.QueryContext(ctx, sqlText, args...)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	out := make([]RawFrameRow, 0)
	for rows.Next() {
		var row RawFrameRow
		var ts scanDateTime
		var eventTime scanDateTime
		var receivedAt scanDateTime
		var parsedFields string
		if err := rows.Scan(
			&ts,
			&row.FrameID,
			&row.EventID,
			&row.MessageID,
			&eventTime,
			&receivedAt,
			&row.RawSizeBytes,
			&row.RawHex,
			&row.RawText,
			&parsedFields,
			&row.ParseStatus,
			&row.ParseError,
			&row.SourceEndpoint,
			&row.Protocol,
			&row.VehicleKey,
			&row.VIN,
			&row.Phone,
			&row.DeviceID,
		); err != nil {
			return nil, err
		}
		row.TS = ts.String
		row.EventTime = eventTime.String
		row.ReceivedAt = receivedAt.String
		row.MessageIDHex = fmt.Sprintf("0x%04X", row.MessageID)
		row.ParsedFields = rawJSONMessage(parsedFields)
		out = append(out, row)
	}
	if err := rows.Err(); err != nil {
		return nil, err
	}
	if err := r.hydratePayloadChunks(ctx, out); err != nil {
		return nil, err
	}
	filterParsedFields(out, query.ParsedFields)
	return out, nil
}

func (r *RawFrameRepository) Count(ctx context.Context, query RawFrameQuery) (int64, error) {
	query = normalizeRawFrameQuery(query)
	sqlText, args := buildRawFrameCountSQL(r.tableName(query), query)
	return countRows(ctx, r.db, sqlText, args...)
}

func (r *LocationRepository) Query(ctx context.Context, query LocationQuery) ([]LocationRow, error) {
	query = normalizeLocationQuery(query)
	sqlText, args := buildLocationSQL(r.tableName(), query)
	rows, err := r.db.QueryContext(ctx, sqlText, args...)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	out := make([]LocationRow, 0)
	for rows.Next() {
		var row LocationRow
		var ts scanDateTime
		var receivedAt scanDateTime
		var altitude sql.NullFloat64
		var speed sql.NullFloat64
		var direction sql.NullInt64
		var alarm sql.NullInt64
		var status sql.NullInt64
		var mileage sql.NullFloat64
		if err := rows.Scan(
			&ts,
			&row.EventID,
			&receivedAt,
			&row.Longitude,
			&row.Latitude,
			&altitude,
			&speed,
			&direction,
			&alarm,
			&status,
			&mileage,
			&row.Protocol,
			&row.VIN,
		); err != nil {
			return nil, err
		}
		row.TS = ts.String
		row.ReceivedAt = receivedAt.String
		row.AltitudeM = nullableFloat(altitude)
		row.SpeedKMH = nullableFloat(speed)
		row.DirectionDeg = nullableInt(direction)
		row.AlarmFlag = nullableInt(alarm)
		row.StatusFlag = nullableInt(status)
		row.TotalMileageKM = nullableFloat(mileage)
		out = append(out, row)
	}
	return out, rows.Err()
}

func (r *LocationRepository) Count(ctx context.Context, query LocationQuery) (int64, error) {
	query = normalizeLocationQuery(query)
	sqlText, args := buildLocationCountSQL(r.tableName(), query)
	return countRows(ctx, r.db, sqlText, args...)
}

func countRows(ctx context.Context, db Queryer, sqlText string, args ...any) (int64, error) {
	rows, err := db.QueryContext(ctx, sqlText, args...)
	if err != nil {
		return 0, err
	}
	defer rows.Close()
	var total int64
	if rows.Next() {
		if err := rows.Scan(&total); err != nil {
			return 0, err
		}
	}
	return total, rows.Err()
}

func (r *RawFrameRepository) tableName(query ...RawFrameQuery) string {
	if len(query) > 0 {
		if child := r.rawChildTableName(query[0]); child != "" {
			return child
		}
	}
	if r.database == "" {
		return "raw_frames"
	}
	return r.database + ".raw_frames"
}

func (r *RawFrameRepository) rawChildTableName(query RawFrameQuery) string {
	protocol := strings.ToUpper(strings.TrimSpace(query.Protocol))
	if protocol == "" {
		return ""
	}
	vehicleKey := strings.TrimSpace(query.VehicleKey)
	if vehicleKey == "" {
		vehicleKey = strings.TrimSpace(query.VIN)
	}
	if vehicleKey == "" {
		return ""
	}
	table := "raw_" + strings.ToLower(protocol) + "_" + hash16(vehicleKey)
	if r.database != "" {
		return r.database + "." + table
	}
	return table
}

func (r *RawFrameRepository) chunkTableName() string {
	if r.database == "" {
		return "raw_frame_payload_chunks"
	}
	return r.database + ".raw_frame_payload_chunks"
}

func (r *LocationRepository) tableName() string {
	if r.database == "" {
		return "vehicle_locations"
	}
	return r.database + ".vehicle_locations"
}

func normalizeRawFrameQuery(query RawFrameQuery) RawFrameQuery {
	query.Protocol = strings.ToUpper(strings.TrimSpace(query.Protocol))
	query.VehicleKey = strings.TrimSpace(query.VehicleKey)
	query.VIN = strings.TrimSpace(query.VIN)
	query.Phone = strings.TrimSpace(query.Phone)
	query.DeviceID = strings.TrimSpace(query.DeviceID)
	query.MessageID = strings.TrimSpace(query.MessageID)
	query.ParsedFields = normalizeParsedFieldNames(query.ParsedFields)
	if len(query.ParsedFields) > 0 {
		query.IncludeFields = true
	}
	query.OrderBy = normalizeRawFrameOrderBy(query.OrderBy)
	query.DateFrom = normalizeDateTimeLiteral(query.DateFrom)
	query.DateTo = normalizeDateTimeLiteral(query.DateTo)
	if query.Limit <= 0 {
		query.Limit = 20
	}
	return query
}

func normalizeLocationQuery(query LocationQuery) LocationQuery {
	query.Protocol = strings.ToUpper(strings.TrimSpace(query.Protocol))
	query.VIN = strings.TrimSpace(query.VIN)
	query.DateFrom = normalizeDateTimeLiteral(query.DateFrom)
	query.DateTo = normalizeDateTimeLiteral(query.DateTo)
	if query.Limit <= 0 {
		query.Limit = 20
	}
	return query
}

func buildRawFrameSQL(table string, query RawFrameQuery) (string, []any) {
	where := rawFrameWhere(query)
	rawHexSelect := "'' AS raw_hex"
	rawTextSelect := "'' AS raw_text"
	parsedFieldsSelect := "'' AS parsed_fields"
	if query.IncludePayload {
		rawHexSelect = "raw_hex"
		rawTextSelect = "raw_text"
	}
	if query.IncludeFields {
		parsedFieldsSelect = "parsed_json AS parsed_fields"
	}
	sqlText := `SELECT ts, frame_id, event_id, message_id, event_time, received_at, raw_size_bytes, ` + rawHexSelect + `, ` + rawTextSelect + `, ` + parsedFieldsSelect + `, parse_status, parse_error, source_endpoint, protocol, vehicle_key, vin, phone, device_id FROM ` + table
	if len(where) > 0 {
		sqlText += " WHERE " + strings.Join(where, " AND ")
	}
	sqlText += " ORDER BY " + rawFrameOrderColumn(query.OrderBy) + " DESC LIMIT " + strconv.Itoa(query.Limit) + " OFFSET " + strconv.Itoa(query.Offset)
	return sqlText, nil
}

func buildRawFrameCountSQL(table string, query RawFrameQuery) (string, []any) {
	sqlText := `SELECT COUNT(*) FROM ` + table
	if where := rawFrameWhere(query); len(where) > 0 {
		sqlText += " WHERE " + strings.Join(where, " AND ")
	}
	return sqlText, nil
}

type payloadChunkManifest struct {
	Chunked     bool   `json:"chunked"`
	PayloadKind string `json:"payload_kind"`
	EventID     string `json:"event_id"`
	ChunkCount  int    `json:"chunk_count"`
}

func (r *RawFrameRepository) hydratePayloadChunks(ctx context.Context, rows []RawFrameRow) error {
	type target struct {
		rowIndex int
		kind     string
		eventID  string
		count    int
	}
	targets := make([]target, 0)
	eventSeen := map[string]struct{}{}
	for index := range rows {
		for _, candidate := range []struct {
			kind  string
			value string
		}{
			{kind: "raw_hex", value: rows[index].RawHex},
			{kind: "raw_text", value: rows[index].RawText},
			{kind: "parsed_fields", value: string(rows[index].ParsedFields)},
		} {
			manifest, ok := parsePayloadChunkManifest(candidate.value)
			if !ok || !payloadKindMatches(candidate.kind, manifest.PayloadKind) || manifest.ChunkCount <= 0 {
				continue
			}
			eventID := strings.TrimSpace(manifest.EventID)
			if eventID == "" {
				eventID = rows[index].EventID
			}
			targets = append(targets, target{
				rowIndex: index,
				kind:     candidate.kind,
				eventID:  eventID,
				count:    manifest.ChunkCount,
			})
			eventSeen[eventID] = struct{}{}
		}
	}
	if len(targets) == 0 {
		return nil
	}

	eventIDs := make([]string, 0, len(eventSeen))
	for eventID := range eventSeen {
		eventIDs = append(eventIDs, eventID)
	}
	sqlText := `SELECT event_id, payload_kind, chunk_index, chunk_text FROM ` + r.chunkTableName() +
		" WHERE event_id IN (" + quotedList(eventIDs) + ") ORDER BY event_id, payload_kind, chunk_index"
	chunkRows, err := r.db.QueryContext(ctx, sqlText)
	if err != nil {
		return err
	}
	defer chunkRows.Close()

	chunks := map[string]map[string][]string{}
	for chunkRows.Next() {
		var eventID string
		var kind string
		var index int
		var text string
		if err := chunkRows.Scan(&eventID, &kind, &index, &text); err != nil {
			return err
		}
		if chunks[eventID] == nil {
			chunks[eventID] = map[string][]string{}
		}
		current := chunks[eventID][kind]
		if index >= len(current) {
			next := make([]string, index+1)
			copy(next, current)
			current = next
		}
		current[index] = text
		chunks[eventID][kind] = current
	}
	if err := chunkRows.Err(); err != nil {
		return err
	}

	for _, target := range targets {
		parts := chunks[target.eventID][target.kind]
		if len(parts) != target.count {
			continue
		}
		hydrated := strings.Join(parts, "")
		switch target.kind {
		case "raw_hex":
			rows[target.rowIndex].RawHex = hydrated
		case "raw_text":
			rows[target.rowIndex].RawText = hydrated
		case "parsed_fields":
			rows[target.rowIndex].ParsedFields = rawJSONMessage(hydrated)
		}
	}
	return nil
}

func rawJSONMessage(value string) json.RawMessage {
	value = strings.TrimSpace(value)
	if value == "" {
		return nil
	}
	if json.Valid([]byte(value)) {
		return json.RawMessage(value)
	}
	return json.RawMessage(jsonString(value))
}

func filterParsedFields(rows []RawFrameRow, fieldNames []string) {
	fieldNames = normalizeParsedFieldNames(fieldNames)
	if len(fieldNames) == 0 {
		return
	}
	for index := range rows {
		if len(rows[index].ParsedFields) == 0 {
			continue
		}
		var fields map[string]any
		if err := json.Unmarshal(rows[index].ParsedFields, &fields); err != nil {
			continue
		}
		filtered := make(map[string]any, len(fieldNames))
		for _, name := range fieldNames {
			if value, ok := fields[name]; ok {
				filtered[name] = value
			}
		}
		if len(filtered) == 0 {
			rows[index].ParsedFields = json.RawMessage(`{}`)
			continue
		}
		rows[index].ParsedFields = rawJSONMessage(jsonString(filtered))
	}
}

func normalizeParsedFieldNames(values []string) []string {
	out := make([]string, 0, len(values))
	seen := map[string]struct{}{}
	for _, value := range values {
		for _, part := range strings.Split(value, ",") {
			name := strings.TrimSpace(part)
			if name == "" {
				continue
			}
			if _, ok := seen[name]; ok {
				continue
			}
			seen[name] = struct{}{}
			out = append(out, name)
		}
	}
	return out
}

func payloadKindMatches(candidate string, manifest string) bool {
	if candidate == manifest {
		return true
	}
	return candidate == "parsed_fields" && manifest == "parsed_json"
}

func parsePayloadChunkManifest(value string) (payloadChunkManifest, bool) {
	var manifest payloadChunkManifest
	if !strings.Contains(value, `"chunked"`) {
		return manifest, false
	}
	if err := json.Unmarshal([]byte(value), &manifest); err != nil {
		return manifest, false
	}
	return manifest, manifest.Chunked
}

func quotedList(values []string) string {
	out := make([]string, 0, len(values))
	for _, value := range values {
		out = append(out, "'"+quote(value)+"'")
	}
	return strings.Join(out, ", ")
}

func buildLocationSQL(table string, query LocationQuery) (string, []any) {
	where := locationWhere(query)
	sqlText := `SELECT ts, event_id, received_at, longitude, latitude, altitude_m, speed_kmh, direction_deg, alarm_flag, status_flag, total_mileage_km, protocol, vin FROM ` + table
	if len(where) > 0 {
		sqlText += " WHERE " + strings.Join(where, " AND ")
	}
	sqlText += " ORDER BY ts DESC LIMIT " + strconv.Itoa(query.Limit) + " OFFSET " + strconv.Itoa(query.Offset)
	return sqlText, nil
}

func buildLocationCountSQL(table string, query LocationQuery) (string, []any) {
	sqlText := `SELECT COUNT(*) FROM ` + table
	if where := locationWhere(query); len(where) > 0 {
		sqlText += " WHERE " + strings.Join(where, " AND ")
	}
	return sqlText, nil
}

func rawFrameWhere(query RawFrameQuery) []string {
	var where []string
	add := func(clause string) {
		where = append(where, clause)
	}
	if query.Protocol != "" {
		add("protocol = '" + quote(query.Protocol) + "'")
	}
	if query.VehicleKey != "" {
		add("vehicle_key = '" + quote(query.VehicleKey) + "'")
	}
	if query.VIN != "" {
		add("vin = '" + quote(query.VIN) + "'")
	}
	if query.Phone != "" {
		add("phone = '" + quote(query.Phone) + "'")
	}
	if query.DeviceID != "" {
		add("device_id = '" + quote(query.DeviceID) + "'")
	}
	if query.MessageID != "" {
		if parsed, ok := parseMessageID(query.MessageID); ok {
			add("message_id = " + strconv.FormatInt(parsed, 10))
		}
	}
	if query.DateFrom != "" {
		add("ts >= '" + quote(normalizeDateTimeLiteral(query.DateFrom)) + "'")
	}
	if query.DateTo != "" {
		add("ts <= '" + quote(normalizeDateTimeLiteral(query.DateTo)) + "'")
	}
	return where
}

func normalizeRawFrameOrderBy(value string) string {
	value = strings.ToLower(strings.TrimSpace(value))
	switch value {
	case "receivedat", "received_at":
		return "receivedAt"
	default:
		return "ts"
	}
}

func rawFrameOrderColumn(value string) string {
	if normalizeRawFrameOrderBy(value) == "receivedAt" {
		return "received_at"
	}
	return "ts"
}

func locationWhere(query LocationQuery) []string {
	var where []string
	add := func(clause string) {
		where = append(where, clause)
	}
	if query.Protocol != "" {
		add("protocol = '" + quote(query.Protocol) + "'")
	}
	if query.VIN != "" {
		add("vin = '" + quote(query.VIN) + "'")
	}
	if query.DateFrom != "" {
		add("ts >= '" + quote(normalizeDateTimeLiteral(query.DateFrom)) + "'")
	}
	if query.DateTo != "" {
		add("ts <= '" + quote(normalizeDateTimeLiteral(query.DateTo)) + "'")
	}
	return where
}

type RawFrameHandler struct {
	repository *RawFrameRepository
}

type LocationHandler struct {
	repository *LocationRepository
}

func NewRawFrameHandler(repository *RawFrameRepository) *RawFrameHandler {
	if repository == nil {
		panic("raw frame repository must not be nil")
	}
	return &RawFrameHandler{repository: repository}
}

func NewLocationHandler(repository *LocationRepository) *LocationHandler {
	if repository == nil {
		panic("location repository must not be nil")
	}
	return &LocationHandler{repository: repository}
}

func (h *RawFrameHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet && r.Method != http.MethodPost {
		writeHistoryError(w, http.StatusMethodNotAllowed, "method not allowed")
		return
	}
	path := strings.Trim(r.URL.Path, "/")
	if path != "api/history/raw-frames" && path != "api/history/raw-frames/query" {
		writeHistoryError(w, http.StatusNotFound, "route not found")
		return
	}
	query, err := rawFrameQueryFromRequest(r)
	if err != nil {
		writeHistoryError(w, http.StatusBadRequest, err.Error())
		return
	}
	var total int64
	if query.IncludeTotal {
		total, err = h.repository.Count(r.Context(), query)
		if err != nil {
			writeHistoryError(w, http.StatusInternalServerError, err.Error())
			return
		}
	}
	rows, err := h.repository.Query(r.Context(), query)
	if err != nil {
		writeHistoryError(w, http.StatusInternalServerError, err.Error())
		return
	}
	if !query.IncludeTotal {
		total = int64(len(rows))
	}
	writeHistoryJSON(w, r, map[string]any{
		"items":  rows,
		"total":  total,
		"limit":  query.Limit,
		"offset": query.Offset,
	})
}

func (h *LocationHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		writeHistoryError(w, http.StatusMethodNotAllowed, "method not allowed")
		return
	}
	if strings.Trim(r.URL.Path, "/") != "api/history/locations" {
		writeHistoryError(w, http.StatusNotFound, "route not found")
		return
	}
	query, err := parseLocationQuery(r)
	if err != nil {
		writeHistoryError(w, http.StatusBadRequest, err.Error())
		return
	}
	var total int64
	if query.IncludeTotal {
		total, err = h.repository.Count(r.Context(), query)
		if err != nil {
			writeHistoryError(w, http.StatusInternalServerError, err.Error())
			return
		}
	}
	rows, err := h.repository.Query(r.Context(), query)
	if err != nil {
		writeHistoryError(w, http.StatusInternalServerError, err.Error())
		return
	}
	if !query.IncludeTotal {
		total = int64(len(rows))
	}
	writeHistoryJSON(w, r, map[string]any{
		"items":  rows,
		"total":  total,
		"limit":  query.Limit,
		"offset": query.Offset,
	})
}

func writeHistoryJSON(w http.ResponseWriter, r *http.Request, value any) {
	w.Header().Set("Content-Type", "application/json")
	w.Header().Add("Vary", "Accept-Encoding")
	if strings.Contains(strings.ToLower(r.Header.Get("Accept-Encoding")), "gzip") {
		w.Header().Set("Content-Encoding", "gzip")
		gzipWriter := gzip.NewWriter(w)
		defer gzipWriter.Close()
		_ = json.NewEncoder(gzipWriter).Encode(value)
		return
	}
	_ = json.NewEncoder(w).Encode(value)
}

func rawFrameQueryFromRequest(r *http.Request) (RawFrameQuery, error) {
	if r.Method == http.MethodPost {
		return parseRawFrameQueryBody(r)
	}
	return parseRawFrameQuery(r)
}

func parseRawFrameQuery(r *http.Request) (RawFrameQuery, error) {
	values := r.URL.Query()
	limit, err := parseBoundedInt(values.Get("limit"), 20, 1, 500, "limit")
	if err != nil {
		return RawFrameQuery{}, err
	}
	offset, err := parseBoundedInt(values.Get("offset"), 0, 0, 1_000_000, "offset")
	if err != nil {
		return RawFrameQuery{}, err
	}
	query := RawFrameQuery{
		Protocol:       values.Get("protocol"),
		VehicleKey:     values.Get("vehicleKey"),
		VIN:            values.Get("vin"),
		Phone:          values.Get("phone"),
		DeviceID:       values.Get("deviceId"),
		MessageID:      values.Get("messageId"),
		OrderBy:        values.Get("orderBy"),
		IncludeFields:  strings.EqualFold(strings.TrimSpace(values.Get("includeFields")), "true"),
		IncludePayload: strings.EqualFold(strings.TrimSpace(values.Get("includePayload")), "true"),
		IncludeTotal:   strings.EqualFold(strings.TrimSpace(values.Get("includeTotal")), "true"),
		ParsedFields:   append(values["fields"], values["parsedFields"]...),
		DateFrom:       values.Get("dateFrom"),
		DateTo:         values.Get("dateTo"),
		Limit:          limit,
		Offset:         offset,
	}
	if !validDateTime(query.DateFrom) || !validDateTime(query.DateTo) {
		return RawFrameQuery{}, errors.New("dateFrom/dateTo must use YYYY-MM-DD or YYYY-MM-DD HH:mm:ss")
	}
	if strings.TrimSpace(query.MessageID) != "" {
		if _, ok := parseMessageID(query.MessageID); !ok {
			return RawFrameQuery{}, errors.New("messageId must be decimal or hex like 0x0200")
		}
	}
	return normalizeRawFrameQuery(query), nil
}

func parseRawFrameQueryBody(r *http.Request) (RawFrameQuery, error) {
	defer r.Body.Close()
	decoder := json.NewDecoder(http.MaxBytesReader(nil, r.Body, 1<<20))
	decoder.DisallowUnknownFields()
	var body rawFrameQueryRequest
	if err := decoder.Decode(&body); err != nil {
		return RawFrameQuery{}, fmt.Errorf("invalid JSON body: %w", err)
	}
	var extra any
	if err := decoder.Decode(&extra); err != io.EOF {
		return RawFrameQuery{}, errors.New("invalid JSON body")
	}
	if body.VehicleKey == "" {
		body.VehicleKey = body.VehicleKeyAlt
	}
	if body.DeviceID == "" {
		body.DeviceID = body.DeviceIDAlt
	}
	if body.MessageID == "" {
		body.MessageID = body.MessageIDAlt
	}
	if body.OrderBy == "" {
		body.OrderBy = body.OrderByAlt
	}
	if body.DateFrom == "" {
		body.DateFrom = body.DateFromAlt
	}
	if body.DateTo == "" {
		body.DateTo = body.DateToAlt
	}
	limit, err := boundedInt(body.Limit, 20, 1, 500, "limit")
	if err != nil {
		return RawFrameQuery{}, err
	}
	offset, err := boundedInt(body.Offset, 0, 0, 1_000_000, "offset")
	if err != nil {
		return RawFrameQuery{}, err
	}
	query := RawFrameQuery{
		Protocol:       body.Protocol,
		VehicleKey:     body.VehicleKey,
		VIN:            body.VIN,
		Phone:          body.Phone,
		DeviceID:       body.DeviceID,
		MessageID:      body.MessageID,
		OrderBy:        body.OrderBy,
		IncludeFields:  body.IncludeFields,
		IncludePayload: body.IncludePayload,
		IncludeTotal:   body.IncludeTotal,
		ParsedFields:   append(body.Fields, body.ParsedFields...),
		DateFrom:       body.DateFrom,
		DateTo:         body.DateTo,
		Limit:          limit,
		Offset:         offset,
	}
	if !validDateTime(query.DateFrom) || !validDateTime(query.DateTo) {
		return RawFrameQuery{}, errors.New("dateFrom/dateTo must use YYYY-MM-DD or YYYY-MM-DD HH:mm:ss")
	}
	if strings.TrimSpace(query.MessageID) != "" {
		if _, ok := parseMessageID(query.MessageID); !ok {
			return RawFrameQuery{}, errors.New("messageId must be decimal or hex like 0x0200")
		}
	}
	return normalizeRawFrameQuery(query), nil
}

func parseLocationQuery(r *http.Request) (LocationQuery, error) {
	values := r.URL.Query()
	limit, err := parseBoundedInt(values.Get("limit"), 20, 1, 500, "limit")
	if err != nil {
		return LocationQuery{}, err
	}
	offset, err := parseBoundedInt(values.Get("offset"), 0, 0, 1_000_000, "offset")
	if err != nil {
		return LocationQuery{}, err
	}
	query := LocationQuery{
		Protocol:     values.Get("protocol"),
		VIN:          values.Get("vin"),
		IncludeTotal: strings.EqualFold(strings.TrimSpace(values.Get("includeTotal")), "true"),
		DateFrom:     values.Get("dateFrom"),
		DateTo:       values.Get("dateTo"),
		Limit:        limit,
		Offset:       offset,
	}
	if !validDateTime(query.DateFrom) || !validDateTime(query.DateTo) {
		return LocationQuery{}, errors.New("dateFrom/dateTo must use YYYY-MM-DD or YYYY-MM-DD HH:mm:ss")
	}
	return normalizeLocationQuery(query), nil
}

func boundedInt(value int, fallback int, min int, max int, name string) (int, error) {
	if value == 0 {
		return fallback, nil
	}
	if value < min || value > max {
		return 0, fmt.Errorf("%s must be between %d and %d", name, min, max)
	}
	return value, nil
}

func parseBoundedInt(raw string, fallback int, min int, max int, name string) (int, error) {
	raw = strings.TrimSpace(raw)
	if raw == "" {
		return fallback, nil
	}
	value, err := strconv.Atoi(raw)
	if err != nil || value < min || value > max {
		return 0, fmt.Errorf("%s must be between %d and %d", name, min, max)
	}
	return value, nil
}

func parseMessageID(value string) (int64, bool) {
	value = strings.TrimSpace(strings.ToLower(value))
	if value == "" {
		return 0, false
	}
	if strings.HasPrefix(value, "0x") {
		parsed, err := strconv.ParseInt(strings.TrimPrefix(value, "0x"), 16, 32)
		return parsed, err == nil
	}
	parsed, err := strconv.ParseInt(value, 10, 32)
	return parsed, err == nil
}

func validDateTime(value string) bool {
	value = normalizeDateTimeLiteral(value)
	if value == "" {
		return true
	}
	for _, layout := range []string{"2006-01-02", "2006-01-02 15:04:05", time.RFC3339} {
		if _, err := time.Parse(layout, value); err == nil {
			return true
		}
	}
	return false
}

func normalizeDateTimeLiteral(value string) string {
	value = strings.TrimSpace(value)
	if value == "" {
		return ""
	}
	shanghai := time.FixedZone("Asia/Shanghai", 8*3600)
	for _, layout := range []string{"2006-01-02T15:04:05", "2006-01-02 15:04:05"} {
		if parsed, err := time.ParseInLocation(layout, value, shanghai); err == nil {
			return parsed.UTC().Format("2006-01-02 15:04:05")
		}
	}
	if parsed, err := time.Parse(time.RFC3339, value); err == nil {
		return parsed.UTC().Format("2006-01-02 15:04:05")
	}
	return value
}

func safeIdentifier(value string) bool {
	if value == "" {
		return false
	}
	for _, r := range value {
		if (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z') || (r >= '0' && r <= '9') || r == '_' {
			continue
		}
		return false
	}
	return true
}

type scanDateTime struct {
	String string
}

func (s *scanDateTime) Scan(value any) error {
	s.String = formatSQLTime(value, "2006-01-02 15:04:05")
	return nil
}

func formatSQLTime(value any, layout string) string {
	switch typed := value.(type) {
	case nil:
		return ""
	case time.Time:
		return typed.Format(layout)
	case []byte:
		return strings.TrimSpace(string(typed))
	case string:
		return strings.TrimSpace(typed)
	default:
		return strings.TrimSpace(fmt.Sprint(typed))
	}
}

func nullableFloat(value sql.NullFloat64) *float64 {
	if !value.Valid {
		return nil
	}
	return &value.Float64
}

func nullableInt(value sql.NullInt64) *int64 {
	if !value.Valid {
		return nil
	}
	return &value.Int64
}

func writeHistoryError(w http.ResponseWriter, status int, message string) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	_ = json.NewEncoder(w).Encode(map[string]any{"error": message})
}