package main

import (
	"context"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net"
	"net/http"
	"strconv"
	"strings"
	"time"

	"code.hackerspace.pl/hscloud/bgpwtf/cccampix/verifier/model"
	"github.com/golang/glog"
)

type rpki struct {
	octorpki string
}

func newRPKI(octorpki string) (processor, error) {
	return &rpki{
		octorpki: octorpki,
	}, nil
}

func (p *rpki) Name() string {
	return "RPKI"
}

func (p *rpki) NextRun(now time.Time, lastFailed bool) time.Time {
	return now.Add(1 * time.Minute)
}

type octorpkiRes struct {
	Metadata struct {
		Counts    int64 `json:"counts"`
		Generated int64 `json:"counts"`
		Valid     int64 `json:"counts"`
	} `json:"metadata"`

	ROAs []octorpkiROA `json:"roas"`
}

type octorpkiROA struct {
	Prefix    string `json:"prefix"`
	MaxLength int64  `json:"maxLength"`
	ASN       string `json:"asn"`
	TA        string `json:"ta"`
}

func (p *rpki) RunAll(ctx context.Context, m model.Model) error {
	peers, err := m.GetCheckablePeers(ctx)
	if err != nil {
		return err
	}

	wantASNs := make(map[string]bool)
	for _, peer := range peers {
		wantASNs[fmt.Sprintf("AS%d", peer.ASN)] = true
	}

	// Get RPKI data dump from OctoRPKI.
	url := fmt.Sprintf("http://%s/output.json", p.octorpki)
	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		return fmt.Errorf("NewRequest(GET %q): %v", url, err)
	}
	req = req.WithContext(ctx)
	client := http.Client{}
	resp, err := client.Do(req)
	if err != nil {
		return fmt.Errorf("GET %q: %v", url, err)
	}
	defer resp.Body.Close()

	data, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return fmt.Errorf("GET %q: %v", url, err)
	}

	if strings.HasPrefix(string(data), "File not ready yet") {
		return fmt.Errorf("OctoRPKI not yet ready")
	}

	var res octorpkiRes
	if err := json.Unmarshal(data, &res); err != nil {
		return fmt.Errorf("Could not decode OctoRPKI output: %v", err)
	}

	// Make list of prefixes we should honor.
	prefixes := make(map[int64][]*model.AllowedPrefix)
	for _, roa := range res.ROAs {
		if !wantASNs[strings.ToUpper(roa.ASN)] {
			continue
		}

		asn, err := strconv.ParseInt(roa.ASN[2:], 10, 64)
		if err != nil {
			glog.Errorf("Invalid ASN: %s %q", roa.ASN, roa.ASN)
			continue
		}

		if _, ok := prefixes[asn]; !ok {
			prefixes[asn] = []*model.AllowedPrefix{}
		}

		_, prefix, err := net.ParseCIDR(roa.Prefix)
		if err != nil {
			glog.Errorf("Invalid prefix: %s %q", roa.ASN, roa.Prefix)
			continue
		}

		prefixes[asn] = append(prefixes[asn], &model.AllowedPrefix{
			Prefix:    *prefix,
			MaxLength: roa.MaxLength,
			TA:        roa.TA,
		})
	}

	for asn, p := range prefixes {
		err := m.UpdateAllowedPrefixes(ctx, asn, p)
		if err != nil {
			return err
		}
	}

	return nil
}