bvandeusen
627b7d1be5
Pure aggregation per spec §6: Seed flag (true when prior < 3), deduplicated Artists ordered by first appearance, Tags bag-of-counts from tracks.genre (empty genres skipped), RecentTrackIDs preserving input order. JSON round-trip verified.
44 lines
1010 B
Go
44 lines
1010 B
Go
package recommendation
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import (
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"github.com/jackc/pgx/v5/pgtype"
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"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
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)
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type SessionVector struct {
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Seed bool `json:"seed"`
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Artists []string `json:"artists"`
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Tags map[string]int `json:"tags"`
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RecentTrackIDs []string `json:"recent_track_ids"`
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}
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func BuildSessionVector(priorTracks []dbq.Track) SessionVector {
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v := SessionVector{
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Seed: len(priorTracks) < 3,
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Artists: []string{},
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Tags: map[string]int{},
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RecentTrackIDs: []string{},
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}
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seen := map[string]bool{}
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for _, t := range priorTracks {
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artistID := uuidString(t.ArtistID)
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if !seen[artistID] {
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seen[artistID] = true
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v.Artists = append(v.Artists, artistID)
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}
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if t.Genre != nil && *t.Genre != "" {
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v.Tags[*t.Genre]++
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}
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v.RecentTrackIDs = append(v.RecentTrackIDs, uuidString(t.ID))
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}
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return v
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}
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func uuidString(u pgtype.UUID) string {
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if !u.Valid {
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return ""
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}
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return u.String()
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}
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