package app

import (
	"encoding/json"
	"errors"
	"fmt"
	"math"
	"net/http"
	"strconv"
	"time"

	"github.com/gorilla/mux"
	promModel "github.com/prometheus/common/model"

	"go.signoz.io/signoz/pkg/query-service/auth"
	"go.signoz.io/signoz/pkg/query-service/constants"
	"go.signoz.io/signoz/pkg/query-service/model"
)

var allowedFunctions = []string{"count", "ratePerSec", "sum", "avg", "min", "max", "p50", "p90", "p95", "p99"}

func parseUser(r *http.Request) (*model.User, error) {

	var user model.User
	if err := json.NewDecoder(r.Body).Decode(&user); err != nil {
		return nil, err
	}
	if len(user.Email) == 0 {
		return nil, fmt.Errorf("email field not found")
	}

	return &user, nil
}

func parseGetTopOperationsRequest(r *http.Request) (*model.GetTopOperationsParams, error) {
	var postData *model.GetTopOperationsParams
	err := json.NewDecoder(r.Body).Decode(&postData)

	if err != nil {
		return nil, err
	}

	postData.Start, err = parseTimeStr(postData.StartTime, "start")
	if err != nil {
		return nil, err
	}
	postData.End, err = parseTimeMinusBufferStr(postData.EndTime, "end")
	if err != nil {
		return nil, err
	}

	if len(postData.ServiceName) == 0 {
		return nil, errors.New("serviceName param missing in query")
	}

	return postData, nil
}

func parseMetricsTime(s string) (time.Time, error) {
	if t, err := strconv.ParseFloat(s, 64); err == nil {
		s, ns := math.Modf(t)
		return time.Unix(int64(s), int64(ns*float64(time.Second))), nil
		// return time.Unix(0, t), nil
	}
	if t, err := time.Parse(time.RFC3339Nano, s); err == nil {
		return t, nil
	}
	return time.Time{}, fmt.Errorf("cannot parse %q to a valid timestamp", s)
}

func parseMetricsDuration(s string) (time.Duration, error) {
	if d, err := strconv.ParseFloat(s, 64); err == nil {
		ts := d * float64(time.Second)
		if ts > float64(math.MaxInt64) || ts < float64(math.MinInt64) {
			return 0, fmt.Errorf("cannot parse %q to a valid duration. It overflows int64", s)
		}
		return time.Duration(ts), nil
	}
	if d, err := promModel.ParseDuration(s); err == nil {
		return time.Duration(d), nil
	}
	return 0, fmt.Errorf("cannot parse %q to a valid duration", s)
}

func parseInstantQueryMetricsRequest(r *http.Request) (*model.InstantQueryMetricsParams, *model.ApiError) {
	var ts time.Time
	if t := r.FormValue("time"); t != "" {
		var err error
		ts, err = parseMetricsTime(t)
		if err != nil {
			return nil, &model.ApiError{Typ: model.ErrorBadData, Err: err}
		}
	} else {
		ts = time.Now()
	}

	return &model.InstantQueryMetricsParams{
		Time:  ts,
		Query: r.FormValue("query"),
		Stats: r.FormValue("stats"),
	}, nil

}

func parseQueryRangeRequest(r *http.Request) (*model.QueryRangeParams, *model.ApiError) {

	start, err := parseMetricsTime(r.FormValue("start"))
	if err != nil {
		return nil, &model.ApiError{Typ: model.ErrorBadData, Err: err}
	}
	end, err := parseMetricsTime(r.FormValue("end"))
	if err != nil {
		return nil, &model.ApiError{Typ: model.ErrorBadData, Err: err}
	}
	if end.Before(start) {
		err := errors.New("end timestamp must not be before start time")
		return nil, &model.ApiError{Typ: model.ErrorBadData, Err: err}
	}

	step, err := parseMetricsDuration(r.FormValue("step"))
	if err != nil {
		return nil, &model.ApiError{Typ: model.ErrorBadData, Err: err}
	}

	if step <= 0 {
		err := errors.New("zero or negative query resolution step widths are not accepted. Try a positive integer")
		return nil, &model.ApiError{Typ: model.ErrorBadData, Err: err}
	}

	// For safety, limit the number of returned points per timeseries.
	// This is sufficient for 60s resolution for a week or 1h resolution for a year.
	if end.Sub(start)/step > 11000 {
		err := errors.New("exceeded maximum resolution of 11,000 points per timeseries. Try decreasing the query resolution (?step=XX)")
		return nil, &model.ApiError{Typ: model.ErrorBadData, Err: err}
	}

	queryRangeParams := model.QueryRangeParams{
		Start: start,
		End:   end,
		Step:  step,
		Query: r.FormValue("query"),
		Stats: r.FormValue("stats"),
	}

	return &queryRangeParams, nil
}

func parseGetUsageRequest(r *http.Request) (*model.GetUsageParams, error) {
	startTime, err := parseTime("start", r)
	if err != nil {
		return nil, err
	}
	endTime, err := parseTime("end", r)
	if err != nil {
		return nil, err
	}

	stepStr := r.URL.Query().Get("step")
	if len(stepStr) == 0 {
		return nil, errors.New("step param missing in query")
	}
	stepInt, err := strconv.Atoi(stepStr)
	if err != nil {
		return nil, errors.New("step param is not in correct format")
	}

	serviceName := r.URL.Query().Get("service")
	stepHour := stepInt / 3600

	getUsageParams := model.GetUsageParams{
		StartTime:   startTime.Format(time.RFC3339Nano),
		EndTime:     endTime.Format(time.RFC3339Nano),
		Start:       startTime,
		End:         endTime,
		ServiceName: serviceName,
		Period:      fmt.Sprintf("PT%dH", stepHour),
		StepHour:    stepHour,
	}

	return &getUsageParams, nil

}

func parseGetServiceOverviewRequest(r *http.Request) (*model.GetServiceOverviewParams, error) {

	var postData *model.GetServiceOverviewParams
	err := json.NewDecoder(r.Body).Decode(&postData)

	if err != nil {
		return nil, err
	}

	postData.Start, err = parseTimeStr(postData.StartTime, "start")
	if err != nil {
		return nil, err
	}
	postData.End, err = parseTimeMinusBufferStr(postData.EndTime, "end")
	if err != nil {
		return nil, err
	}

	postData.Period = fmt.Sprintf("PT%dM", postData.StepSeconds/60)
	return postData, nil
}

func parseGetServicesRequest(r *http.Request) (*model.GetServicesParams, error) {

	var postData *model.GetServicesParams
	err := json.NewDecoder(r.Body).Decode(&postData)

	if err != nil {
		return nil, err
	}

	postData.Start, err = parseTimeStr(postData.StartTime, "start")
	if err != nil {
		return nil, err
	}
	postData.End, err = parseTimeMinusBufferStr(postData.EndTime, "end")
	if err != nil {
		return nil, err
	}

	postData.Period = int(postData.End.Unix() - postData.Start.Unix())
	return postData, nil
}

func DoesExistInSlice(item string, list []string) bool {
	for _, element := range list {
		if item == element {
			return true
		}
	}
	return false
}

func parseSpanFilterRequestBody(r *http.Request) (*model.SpanFilterParams, error) {

	var postData *model.SpanFilterParams
	err := json.NewDecoder(r.Body).Decode(&postData)

	if err != nil {
		return nil, err
	}

	postData.Start, err = parseTimeStr(postData.StartStr, "start")
	if err != nil {
		return nil, err
	}
	postData.End, err = parseTimeMinusBufferStr(postData.EndStr, "end")
	if err != nil {
		return nil, err
	}

	return postData, nil
}

func parseFilteredSpansRequest(r *http.Request) (*model.GetFilteredSpansParams, error) {

	var postData *model.GetFilteredSpansParams
	err := json.NewDecoder(r.Body).Decode(&postData)

	if err != nil {
		return nil, err
	}

	postData.Start, err = parseTimeStr(postData.StartStr, "start")
	if err != nil {
		return nil, err
	}
	postData.End, err = parseTimeMinusBufferStr(postData.EndStr, "end")
	if err != nil {
		return nil, err
	}

	if postData.Limit == 0 {
		postData.Limit = 10
	}

	return postData, nil
}

func parseFilteredSpanAggregatesRequest(r *http.Request) (*model.GetFilteredSpanAggregatesParams, error) {

	var postData *model.GetFilteredSpanAggregatesParams
	err := json.NewDecoder(r.Body).Decode(&postData)

	if err != nil {
		return nil, err
	}

	postData.Start, err = parseTimeStr(postData.StartStr, "start")
	if err != nil {
		return nil, err
	}
	postData.End, err = parseTimeMinusBufferStr(postData.EndStr, "end")
	if err != nil {
		return nil, err
	}

	step := postData.StepSeconds
	if step == 0 {
		return nil, errors.New("step param missing in query")
	}

	function := postData.Function
	if len(function) == 0 {
		return nil, errors.New("function param missing in query")
	} else {
		if !DoesExistInSlice(function, allowedFunctions) {
			return nil, errors.New(fmt.Sprintf("given function: %s is not allowed in query", function))
		}
	}

	var dimension, aggregationOption string

	switch function {
	case "count":
		dimension = "calls"
		aggregationOption = "count"
	case "ratePerSec":
		dimension = "calls"
		aggregationOption = "rate_per_sec"
	case "avg":
		dimension = "duration"
		aggregationOption = "avg"
	case "sum":
		dimension = "duration"
		aggregationOption = "sum"
	case "p50":
		dimension = "duration"
		aggregationOption = "p50"
	case "p90":
		dimension = "duration"
		aggregationOption = "p90"
	case "p95":
		dimension = "duration"
		aggregationOption = "p95"
	case "p99":
		dimension = "duration"
		aggregationOption = "p99"
	case "min":
		dimension = "duration"
		aggregationOption = "min"
	case "max":
		dimension = "duration"
		aggregationOption = "max"
	}

	postData.AggregationOption = aggregationOption
	postData.Dimension = dimension
	// tags, err := parseTagsV2("tags", r)
	// if err != nil {
	// 	return nil, err
	// }
	// if len(*tags) != 0 {
	// 	params.Tags = *tags
	// }

	return postData, nil
}

func parseTagFilterRequest(r *http.Request) (*model.TagFilterParams, error) {
	var postData *model.TagFilterParams
	err := json.NewDecoder(r.Body).Decode(&postData)

	if err != nil {
		return nil, err
	}

	postData.Start, err = parseTimeStr(postData.StartStr, "start")
	if err != nil {
		return nil, err
	}
	postData.End, err = parseTimeMinusBufferStr(postData.EndStr, "end")
	if err != nil {
		return nil, err
	}

	return postData, nil

}

func parseTagValueRequest(r *http.Request) (*model.TagFilterParams, error) {
	var postData *model.TagFilterParams
	err := json.NewDecoder(r.Body).Decode(&postData)

	if err != nil {
		return nil, err
	}
	if postData.TagKey == "" {
		return nil, fmt.Errorf("%s param missing in query", postData.TagKey)
	}

	postData.Start, err = parseTimeStr(postData.StartStr, "start")
	if err != nil {
		return nil, err
	}
	postData.End, err = parseTimeMinusBufferStr(postData.EndStr, "end")
	if err != nil {
		return nil, err
	}

	return postData, nil

}

func parseListErrorsRequest(r *http.Request) (*model.ListErrorsParams, error) {

	var allowedOrderParams = []string{"exceptionType", "exceptionCount", "firstSeen", "lastSeen", "serviceName"}
	var allowedOrderDirections = []string{"ascending", "descending"}

	startTime, err := parseTime("start", r)
	if err != nil {
		return nil, err
	}
	endTime, err := parseTimeMinusBuffer("end", r)
	if err != nil {
		return nil, err
	}

	order := r.URL.Query().Get("order")
	if len(order) > 0 && !DoesExistInSlice(order, allowedOrderDirections) {
		return nil, errors.New(fmt.Sprintf("given order: %s is not allowed in query", order))
	}
	orderParam := r.URL.Query().Get("orderParam")
	if len(order) > 0 && !DoesExistInSlice(orderParam, allowedOrderParams) {
		return nil, errors.New(fmt.Sprintf("given orderParam: %s is not allowed in query", orderParam))
	}
	limit := r.URL.Query().Get("limit")
	offset := r.URL.Query().Get("offset")

	if len(offset) == 0 || len(limit) == 0 {
		return nil, fmt.Errorf("offset or limit param cannot be empty from the query")
	}

	limitInt, err := strconv.Atoi(limit)
	if err != nil {
		return nil, errors.New("limit param is not in correct format")
	}
	offsetInt, err := strconv.Atoi(offset)
	if err != nil {
		return nil, errors.New("offset param is not in correct format")
	}

	params := &model.ListErrorsParams{
		Start:      startTime,
		End:        endTime,
		OrderParam: orderParam,
		Order:      order,
		Limit:      int64(limitInt),
		Offset:     int64(offsetInt),
	}

	return params, nil
}

func parseCountErrorsRequest(r *http.Request) (*model.CountErrorsParams, error) {

	startTime, err := parseTime("start", r)
	if err != nil {
		return nil, err
	}
	endTime, err := parseTimeMinusBuffer("end", r)
	if err != nil {
		return nil, err
	}

	params := &model.CountErrorsParams{
		Start: startTime,
		End:   endTime,
	}

	return params, nil
}

func parseGetErrorRequest(r *http.Request) (*model.GetErrorParams, error) {

	timestamp, err := parseTime("timestamp", r)
	if err != nil {
		return nil, err
	}

	groupID := r.URL.Query().Get("groupID")

	if len(groupID) == 0 {
		return nil, fmt.Errorf("groupID param cannot be empty from the query")
	}
	errorID := r.URL.Query().Get("errorID")

	params := &model.GetErrorParams{
		Timestamp: timestamp,
		GroupID:   groupID,
		ErrorID:   errorID,
	}

	return params, nil
}

func parseTimeStr(timeStr string, param string) (*time.Time, error) {

	if len(timeStr) == 0 {
		return nil, fmt.Errorf("%s param missing in query", param)
	}

	timeUnix, err := strconv.ParseInt(timeStr, 10, 64)
	if err != nil || len(timeStr) == 0 {
		return nil, fmt.Errorf("%s param is not in correct timestamp format", param)
	}

	timeFmt := time.Unix(0, timeUnix)

	return &timeFmt, nil

}

func parseTimeMinusBufferStr(timeStr string, param string) (*time.Time, error) {

	if len(timeStr) == 0 {
		return nil, fmt.Errorf("%s param missing in query", param)
	}

	timeUnix, err := strconv.ParseInt(timeStr, 10, 64)
	if err != nil || len(timeStr) == 0 {
		return nil, fmt.Errorf("%s param is not in correct timestamp format", param)
	}

	timeUnixNow := time.Now().UnixNano()
	if timeUnix > timeUnixNow-30000000000 {
		timeUnix = timeUnix - 30000000000
	}

	timeFmt := time.Unix(0, timeUnix)

	return &timeFmt, nil

}

func parseTime(param string, r *http.Request) (*time.Time, error) {

	timeStr := r.URL.Query().Get(param)
	if len(timeStr) == 0 {
		return nil, fmt.Errorf("%s param missing in query", param)
	}

	timeUnix, err := strconv.ParseInt(timeStr, 10, 64)
	if err != nil || len(timeStr) == 0 {
		return nil, fmt.Errorf("%s param is not in correct timestamp format", param)
	}

	timeFmt := time.Unix(0, timeUnix)

	return &timeFmt, nil

}

func parseTimeMinusBuffer(param string, r *http.Request) (*time.Time, error) {

	timeStr := r.URL.Query().Get(param)
	if len(timeStr) == 0 {
		return nil, fmt.Errorf("%s param missing in query", param)
	}

	timeUnix, err := strconv.ParseInt(timeStr, 10, 64)
	if err != nil || len(timeStr) == 0 {
		return nil, fmt.Errorf("%s param is not in correct timestamp format", param)
	}

	timeUnixNow := time.Now().UnixNano()
	if timeUnix > timeUnixNow-30000000000 {
		timeUnix = timeUnix - 30000000000
	}

	timeFmt := time.Unix(0, timeUnix)

	return &timeFmt, nil

}

func parseTTLParams(r *http.Request) (*model.TTLParams, error) {

	// make sure either of the query params are present
	typeTTL := r.URL.Query().Get("type")
	delDuration := r.URL.Query().Get("duration")
	coldStorage := r.URL.Query().Get("coldStorage")
	toColdDuration := r.URL.Query().Get("toColdDuration")

	if len(typeTTL) == 0 || len(delDuration) == 0 {
		return nil, fmt.Errorf("type and duration param cannot be empty from the query")
	}

	// Validate the type parameter
	if typeTTL != constants.TraceTTL && typeTTL != constants.MetricsTTL && typeTTL != constants.LogsTTL {
		return nil, fmt.Errorf("type param should be metrics|traces|logs, got %v", typeTTL)
	}

	// Validate the TTL duration.
	durationParsed, err := time.ParseDuration(delDuration)
	if err != nil || durationParsed.Seconds() <= 0 {
		return nil, fmt.Errorf("Not a valid TTL duration %v", delDuration)
	}

	var toColdParsed time.Duration

	// If some cold storage is provided, validate the cold storage move TTL.
	if len(coldStorage) > 0 {
		toColdParsed, err = time.ParseDuration(toColdDuration)
		if err != nil || toColdParsed.Seconds() <= 0 {
			return nil, fmt.Errorf("Not a valid toCold TTL duration %v", toColdDuration)
		}
		if toColdParsed.Seconds() != 0 && toColdParsed.Seconds() >= durationParsed.Seconds() {
			return nil, fmt.Errorf("Delete TTL should be greater than cold storage move TTL.")
		}
	}

	return &model.TTLParams{
		Type:                  typeTTL,
		DelDuration:           int64(durationParsed.Seconds()),
		ColdStorageVolume:     coldStorage,
		ToColdStorageDuration: int64(toColdParsed.Seconds()),
	}, nil
}

func parseGetTTL(r *http.Request) (*model.GetTTLParams, error) {

	typeTTL := r.URL.Query().Get("type")

	if len(typeTTL) == 0 {
		return nil, fmt.Errorf("type param cannot be empty from the query")
	} else {
		// Validate the type parameter
		if typeTTL != constants.TraceTTL && typeTTL != constants.MetricsTTL && typeTTL != constants.LogsTTL {
			return nil, fmt.Errorf("type param should be metrics|traces|logs, got %v", typeTTL)
		}
	}

	return &model.GetTTLParams{Type: typeTTL}, nil
}

func parseUserRequest(r *http.Request) (*model.User, error) {
	var req model.User
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		return nil, err
	}
	return &req, nil
}

func parseInviteRequest(r *http.Request) (*model.InviteRequest, error) {
	var req model.InviteRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		return nil, err
	}
	return &req, nil
}

func parseRegisterRequest(r *http.Request) (*auth.RegisterRequest, error) {
	var req auth.RegisterRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		return nil, err
	}

	if err := auth.ValidatePassword(req.Password); err != nil {
		return nil, err
	}

	return &req, nil
}

func parseLoginRequest(r *http.Request) (*model.LoginRequest, error) {
	var req model.LoginRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		return nil, err
	}

	return &req, nil
}

func parseUserRoleRequest(r *http.Request) (*model.UserRole, error) {
	var req model.UserRole
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		return nil, err
	}

	return &req, nil
}

func parseEditOrgRequest(r *http.Request) (*model.Organization, error) {
	var req model.Organization
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		return nil, err
	}

	return &req, nil
}

func parseResetPasswordRequest(r *http.Request) (*model.ResetPasswordRequest, error) {
	var req model.ResetPasswordRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		return nil, err
	}
	if err := auth.ValidatePassword(req.Password); err != nil {
		return nil, err
	}

	return &req, nil
}

func parseChangePasswordRequest(r *http.Request) (*model.ChangePasswordRequest, error) {
	id := mux.Vars(r)["id"]
	var req model.ChangePasswordRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		return nil, err
	}
	req.UserId = id
	if err := auth.ValidatePassword(req.NewPassword); err != nil {
		return nil, err
	}

	return &req, nil
}

func parseFilterSet(r *http.Request) (*model.FilterSet, error) {
	var filterSet model.FilterSet
	err := json.NewDecoder(r.Body).Decode(&filterSet)
	if err != nil {
		return nil, err
	}
	return &filterSet, nil
}