package main

// The data sources band-opening detection depends on, and the settings that
// switch them on.
//
// The detection shipped reading whatever the operator's cluster nodes happened
// to carry. That was a design mistake of the worst kind: the feature depended
// on RBN feeds and a PSK Reporter subscription that nobody could know were
// needed, so it looked broken rather than unconfigured. Nexus showed a 6 m
// opening with 869 stations while OpsLog, on the same PC, showed nothing.
//
// So enabling the watch ARRANGES ITS OWN SOURCES: it adds the two RBN nodes if
// they are missing and brings the PSK Reporter feed up. Turning it off leaves
// the nodes alone — they may have been wanted for their own sake, and silently
// removing a cluster node an operator is using would be worse than leaving one
// they no longer need.

import (
	"strings"

	"hamlog/internal/applog"
	"hamlog/internal/bandopen"
	"hamlog/internal/cluster"
	"hamlog/internal/pskr"
)

const (
	keyBandOpenEnabled = "bandopen.enabled"
	keyBandOpenBands   = "bandopen.bands" // comma-separated; empty = the default set
)

// rbnNodes are the two Reverse Beacon Network endpoints the watch wants: CW and
// digital are separate ports and carry different skimmers.
var rbnNodes = []cluster.ServerConfig{
	{Name: "RBN CW", Host: "telnet.reversebeacon.net", Port: 7000, Enabled: true},
	{Name: "RBN FTx", Host: "telnet.reversebeacon.net", Port: 7001, Enabled: true},
}

// BandOpenSettings is the panel's shape.
type BandOpenSettings struct {
	Enabled bool     `json:"enabled"`
	Bands   []string `json:"bands"`
	// Available is every band that can be watched, so the UI does not carry its
	// own copy of a list that belongs to the detector.
	Available []string `json:"available"`
}

func (a *App) GetBandOpenSettings() BandOpenSettings {
	s := BandOpenSettings{
		Enabled:   a.settingOr(keyBandOpenEnabled, "") == "1",
		Bands:     splitCSV(a.settingOr(keyBandOpenBands, "")),
		Available: pskr.Bands,
	}
	if len(s.Bands) == 0 {
		s.Bands = append(s.Bands, pskr.Bands...)
	}
	return s
}

func (a *App) SaveBandOpenSettings(s BandOpenSettings) error {
	a.setSetting(keyBandOpenEnabled, map[bool]string{true: "1", false: "0"}[s.Enabled])
	a.setSetting(keyBandOpenBands, strings.Join(s.Bands, ","))
	if s.Enabled {
		a.ensureRBNNodes()
	}
	a.startBandOpenFeed()
	return nil
}

// ensureRBNNodes adds the RBN endpoints when they are absent.
//
// Matched on host AND port rather than on name: an operator who renamed theirs
// "Skimmers CW" has the node, and adding a second one pointed at the same
// server would give them every spot twice — which the detector would read as
// twice as many stations, i.e. an opening that is not there.
func (a *App) ensureRBNNodes() {
	have, err := a.ListClusterServers()
	if err != nil {
		applog.Printf("bandopen: cannot read the cluster nodes (%v) — not adding RBN", err)
		return
	}
	for _, want := range rbnNodes {
		found := false
		for _, h := range have {
			if strings.EqualFold(strings.TrimSpace(h.Host), want.Host) && h.Port == want.Port {
				found = true
				break
			}
		}
		if found {
			continue
		}
		if _, err := a.SaveClusterServer(want); err != nil {
			applog.Printf("bandopen: could not add %s: %v", want.Name, err)
			continue
		}
		applog.Printf("bandopen: added cluster node %s (%s:%d) — the watch needs it",
			want.Name, want.Host, want.Port)
	}
}

// startBandOpenFeed brings the PSK Reporter subscription up or down to match
// the setting. Called at startup and whenever the setting is saved.
func (a *App) startBandOpenFeed() {
	if a.pskr != nil {
		a.pskr.Stop()
		a.pskr = nil
	}
	s := a.GetBandOpenSettings()
	if !s.Enabled {
		return
	}
	// Every spot is measured from the operator's position. Without one there is
	// nothing to measure, and a detector fed unmeasurable spots reports nothing
	// while looking like it is working.
	if !a.opSet {
		applog.Printf("bandopen: no station grid set — the opening watch needs one to measure a path")
		return
	}
	a.pskr = pskr.New(pskr.Config{
		Bands: s.Bands,
		OpLat: a.opLat, OpLon: a.opLon,
		Geo: func(grid string) (int, int, bool) {
			lat, lon, ok := gridToLatLon(grid)
			if !ok {
				return 0, 0, false
			}
			// The same arithmetic the cluster path uses, so one spot cannot be
			// 2000 km away down one road and 2100 km down the other.
			d := int(haversineKm(a.opLat, a.opLon, lat, lon) + 0.5)
			b := int(initialBearingDeg(a.opLat, a.opLon, lat, lon) + 0.5)
			return d, b, true
		},
		OnSpot: a.feedBandOpen,
		Logf:   applog.Printf,
	})
	if err := a.pskr.Start(); err != nil {
		applog.Printf("bandopen: PSK Reporter feed did not start: %v", err)
	}
}

// feedBandOpen hands one PSK Reporter decode to the detector.
//
// Called from the MQTT goroutine at up to thousands a minute when 6 m is open,
// so it does the least possible: the detector's own window and de-duplication
// by callsign are what turn that flood into one announcement.
func (a *App) feedBandOpen(s pskr.Spot) {
	if !bandopen.Watched(s.Band) {
		return
	}
	a.bandOpen.mu.Lock()
	if a.bandOpen.det == nil {
		a.bandOpen.det = bandopen.New(bandopen.DefaultConfig())
	}
	op := a.bandOpen.det.Add(bandopen.Spot{
		Call: s.Call, Band: s.Band, DistKm: s.DistKm, Bearing: s.Bearing, At: s.At,
	}, a.opLat)
	if op != nil {
		a.bandOpen.last = append([]bandopen.Opening{*op}, a.bandOpen.last...)
		if len(a.bandOpen.last) > maxRememberedOpenings {
			a.bandOpen.last = a.bandOpen.last[:maxRememberedOpenings]
		}
	}
	a.bandOpen.mu.Unlock()
	if op != nil {
		a.announceOpening(*op)
	}
}

// GetPSKReporterStatus is what the settings panel polls.
func (a *App) GetPSKReporterStatus() pskr.Status {
	if a.pskr == nil {
		return pskr.Status{Bands: pskr.Bands}
	}
	return a.pskr.Status()
}

// settingOr reads one key, falling back when the store is not up yet or the
// value is blank. The settings store is a plain string key/value and every
// caller does this by hand; two of them here earn the helper.
func (a *App) settingOr(key, def string) string {
	if a.settings == nil {
		return def
	}
	v, _ := a.settings.Get(a.ctx, key)
	if strings.TrimSpace(v) == "" {
		return def
	}
	return v
}

func splitCSV(s string) []string {
	var out []string
	for _, p := range strings.Split(s, ",") {
		if p = strings.TrimSpace(p); p != "" {
			out = append(out, p)
		}
	}
	return out
}