// Copyright 2022 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package main

import (
	"context"

	"cloud.google.com/go/bigquery"
	"github.com/maruel/subcommands"
	"go.chromium.org/luci/auth"
	"go.chromium.org/luci/auth/client/authcli"
	"golang.org/x/exp/constraints"
	"google.golang.org/api/iterator"
)

type commonFlags struct {
	subcommands.CommandRunBase
	authFlags authcli.Flags
	project   string

	parsedAuthOpts auth.Options
}

func (c *commonFlags) Init(authOpts auth.Options) {
	c.authFlags = authcli.Flags{}
	c.authFlags.Register(&c.Flags, authOpts)
}

func (c *commonFlags) Parse() error {
	var err error
	c.parsedAuthOpts, err = c.authFlags.Options()
	if err != nil {
		return err
	}
	return nil
}

func runQuery[T any](ctx context.Context, client *bigquery.Client, query string, params map[string]any) ([]T, error) {
	q := client.Query(query)
	for k, v := range params {
		q.Parameters = append(q.Parameters, bigquery.QueryParameter{Name: k, Value: v})
	}
	iter, err := q.Read(ctx)
	if err != nil {
		return nil, err
	}

	var rows []T
	for {
		var row T
		err := iter.Next(&row)
		if err == iterator.Done {
			break
		} else if err != nil {
			return nil, err
		}
		rows = append(rows, row)
	}

	return rows, nil
}

func average[T constraints.Float | constraints.Integer](nums []T) float64 {
	if len(nums) == 0 {
		panic("average of empty slice")
	}
	var sum T
	for _, num := range nums {
		sum += num
	}
	return float64(sum) / float64(len(nums))
}