57 lines
1.3 KiB
Go
57 lines
1.3 KiB
Go
package geo
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import (
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"encoding/json"
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"fmt"
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"math"
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"os"
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"path/filepath"
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"git.leaktechnologies.dev/Leak_Technologies/Skyfeed/internal/config"
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)
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// Town represents a Canadian town record (loaded from towns.json).
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type Town struct {
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Name string `json:"name"`
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Province string `json:"province"`
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Lat float64 `json:"lat"`
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Lon float64 `json:"lon"`
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}
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// FindNearestTown loads the cached towns.json and finds the closest town to given coordinates.
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func FindNearestTown(lat, lon float64) (Town, error) {
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townsPath := filepath.Join(config.DataDir, "towns.json")
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data, err := os.ReadFile(townsPath)
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if err != nil {
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return Town{}, fmt.Errorf("failed to read town index: %w", err)
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}
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var towns []Town
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if err := json.Unmarshal(data, &towns); err != nil {
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return Town{}, fmt.Errorf("failed to parse towns.json: %w", err)
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}
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if len(towns) == 0 {
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return Town{}, fmt.Errorf("no towns found in index")
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}
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minDist := math.MaxFloat64
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var nearest Town
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for _, t := range towns {
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d := Haversine(lat, lon, t.Lat, t.Lon) // ✅ use shared helper from stations.go
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if d < minDist {
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minDist = d
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nearest = t
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}
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}
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if nearest.Name == "" {
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return Town{}, fmt.Errorf("no nearby town found")
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}
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fmt.Printf("[geo] Nearest town: %s, %s (%.2f km)\n", nearest.Name, nearest.Province, minDist)
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return nearest, nil
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}
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