package pipeline

import (
	"sdr-wideband-suite/internal/classifier"
	"sdr-wideband-suite/internal/detector"
)

// Candidate is the coarse output of the surveillance detector.
// It intentionally stays lightweight and cheap to produce.
type Candidate struct {
	ID            int64                   `json:"id"`
	CenterHz      float64                 `json:"center_hz"`
	BandwidthHz   float64                 `json:"bandwidth_hz"`
	PeakDb        float64                 `json:"peak_db"`
	SNRDb         float64                 `json:"snr_db"`
	FirstBin      int                     `json:"first_bin"`
	LastBin       int                     `json:"last_bin"`
	NoiseDb       float64                 `json:"noise_db,omitempty"`
	Source        string                  `json:"source,omitempty"`
	Hint          string                  `json:"hint,omitempty"`
	Evidence      []LevelEvidence         `json:"evidence,omitempty"`
	EvidenceState *CandidateEvidenceState `json:"evidence_state,omitempty"`
}

// LevelEvidence captures which analysis level produced a candidate.
// This is intentionally lightweight for later multi-level fusion.
type LevelEvidence struct {
	Level      AnalysisLevel `json:"level"`
	Provenance string        `json:"provenance,omitempty"`
}

// RefinementWindow describes the local analysis span that refinement should use.
type RefinementWindow struct {
	CenterHz float64 `json:"center_hz"`
	SpanHz   float64 `json:"span_hz"`
	Source   string  `json:"source,omitempty"`
}

// Refinement contains higher-cost local analysis derived from a candidate.
type Refinement struct {
	Candidate   Candidate                  `json:"candidate"`
	Window      RefinementWindow           `json:"window"`
	Signal      detector.Signal            `json:"signal"`
	SnippetRate int                        `json:"snippet_rate"`
	Class       *classifier.Classification `json:"class,omitempty"`
	Stage       string                     `json:"stage,omitempty"`
}

func CandidatesFromSignals(signals []detector.Signal, source string) []Candidate {
	out := make([]Candidate, 0, len(signals))
	for _, s := range signals {
		hint := ""
		if s.Class != nil {
			hint = string(s.Class.ModType)
		}
		out = append(out, Candidate{
			ID:          s.ID,
			CenterHz:    s.CenterHz,
			BandwidthHz: s.BWHz,
			PeakDb:      s.PeakDb,
			SNRDb:       s.SNRDb,
			FirstBin:    s.FirstBin,
			LastBin:     s.LastBin,
			NoiseDb:     s.NoiseDb,
			Source:      source,
			Hint:        hint,
		})
	}
	return out
}

func CandidatesFromSignalsWithLevel(signals []detector.Signal, source string, level AnalysisLevel) []Candidate {
	out := CandidatesFromSignals(signals, source)
	if level.Name == "" && level.FFTSize == 0 && level.SampleRate == 0 {
		return out
	}
	evidence := LevelEvidence{Level: level, Provenance: source}
	for i := range out {
		AddCandidateEvidence(&out[i], evidence)
	}
	return out
}