viye/internal/plumbing/weather/weather.go (view raw)
| 1 | package weather |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "encoding/json" |
| 6 | "errors" |
| 7 | "fmt" |
| 8 | "net/http" |
| 9 | "net/url" |
| 10 | "strconv" |
| 11 | "time" |
| 12 | |
| 13 | "github.com/olexsmir/viye/internal/config" |
| 14 | "github.com/olexsmir/viye/internal/viye" |
| 15 | ) |
| 16 | |
| 17 | type Tool struct{} |
| 18 | |
| 19 | func (Tool) Name() string { return "weather" } |
| 20 | func (Tool) Match(c *viye.Context) bool { return c.Cmd == "weather" } |
| 21 | func (Tool) Execute(c *viye.Context) (string, error) { |
| 22 | city, err := getCity(c) |
| 23 | if err != nil { |
| 24 | return "", err |
| 25 | } |
| 26 | |
| 27 | fc, err := forecast(city) |
| 28 | if err != nil { |
| 29 | return "", err |
| 30 | } |
| 31 | |
| 32 | return viye.FormatOutput(render(city, fc)), nil |
| 33 | } |
| 34 | |
| 35 | func getCity(c *viye.Context) (string, error) { |
| 36 | var city string |
| 37 | if len(c.Args) == 1 { |
| 38 | city = c.Args[0] |
| 39 | } else { |
| 40 | cfg, err := config.Load() |
| 41 | if err != nil { |
| 42 | return "", err |
| 43 | } |
| 44 | city = cfg.Get("city") |
| 45 | } |
| 46 | if city == "" { |
| 47 | return "", errors.New("please provide a city option") |
| 48 | } |
| 49 | return city, nil |
| 50 | } |
| 51 | |
| 52 | func render(city string, fc weatherResp) []string { |
| 53 | if len(fc.Weather) < 3 || len(fc.Weather[0].Hourly) < 8 { |
| 54 | return []string{"no forecast data"} |
| 55 | } |
| 56 | |
| 57 | t := fc.Weather[0].Hourly |
| 58 | lines := []string{} |
| 59 | lines = append(lines, fmt.Sprintf("%s (%s)", city, fc.Weather[0].Date)) |
| 60 | lines = append(lines, fmt.Sprintf("Today %s %s° / %s %s° / %s %s°", |
| 61 | emoji(t[2].Code), t[2].TempC, // morning |
| 62 | emoji(t[4].Code), t[4].TempC, // midday |
| 63 | emoji(t[7].Code), t[7].TempC)) // evening |
| 64 | |
| 65 | for _, d := range fc.Weather[1:3] { |
| 66 | mi, _ := strconv.Atoi(d.Min) |
| 67 | ma, _ := strconv.Atoi(d.Max) |
| 68 | lines = append(lines, fmt.Sprintf("%-5s %s %.0f° (avg)", |
| 69 | weekday(d.Date), emoji(d.Hourly[4].Code), (float64(mi)+float64(ma))/2)) |
| 70 | } |
| 71 | return lines |
| 72 | } |
| 73 | |
| 74 | func weekday(date string) string { |
| 75 | t, _ := time.Parse("2006-01-02", date) |
| 76 | return t.Weekday().String()[:3] |
| 77 | } |
| 78 | |
| 79 | // api |
| 80 | |
| 81 | type weatherResp struct { |
| 82 | Weather []day `json:"weather"` |
| 83 | } |
| 84 | |
| 85 | // hour is one 3-hourly reading; 8 readings cover a day, hours 0..21. |
| 86 | type hour struct { |
| 87 | TempC string `json:"tempC"` |
| 88 | Code string `json:"weatherCode"` |
| 89 | } |
| 90 | |
| 91 | type day struct { |
| 92 | Date string `json:"date"` |
| 93 | Min string `json:"mintempC"` |
| 94 | Max string `json:"maxtempC"` |
| 95 | Hourly []hour `json:"hourly"` |
| 96 | } |
| 97 | |
| 98 | // forecast fetches the 3-day forecast for a city via wttr.in (Open-Meteo data). |
| 99 | func forecast(city string) (weatherResp, error) { |
| 100 | u := "https://wttr.in/" + url.QueryEscape(city) + "?format=j1" |
| 101 | ctx, cancel := context.WithTimeout(context.Background(), viye.Timeout) |
| 102 | defer cancel() |
| 103 | |
| 104 | req, err := http.NewRequestWithContext(ctx, http.MethodGet, u, nil) |
| 105 | if err != nil { |
| 106 | return weatherResp{}, err |
| 107 | } |
| 108 | resp, err := http.DefaultClient.Do(req) |
| 109 | if err != nil { |
| 110 | return weatherResp{}, err |
| 111 | } |
| 112 | defer resp.Body.Close() |
| 113 | if resp.StatusCode != http.StatusOK { |
| 114 | return weatherResp{}, fmt.Errorf("api returned %s", resp.Status) |
| 115 | } |
| 116 | |
| 117 | var out weatherResp |
| 118 | if err := json.NewDecoder(resp.Body).Decode(&out); err != nil { |
| 119 | return weatherResp{}, err |
| 120 | } |
| 121 | if len(out.Weather) == 0 { |
| 122 | return weatherResp{}, fmt.Errorf("city %q not found", city) |
| 123 | } |
| 124 | return out, nil |
| 125 | } |
| 126 | |
| 127 | // emoji maps a wttr.in weather code to its phenomenon emoji. |
| 128 | func emoji(code string) string { |
| 129 | c, _ := strconv.Atoi(code) |
| 130 | switch { |
| 131 | case c == 113: |
| 132 | return "☀️" |
| 133 | case c == 116: |
| 134 | return "🌤️" |
| 135 | case c == 119 || c == 122: |
| 136 | return "☁️" |
| 137 | case c == 143 || c == 248 || c == 260: |
| 138 | return "🌫️" |
| 139 | case c == 179 || c == 227 || c == 230 || |
| 140 | c >= 317 && c <= 338 || c == 350 || |
| 141 | c >= 362 && c <= 377 || c == 392 || c == 395: // snow, sleet |
| 142 | return "🌨️" |
| 143 | case c == 176 || c == 182 || c == 185 || c == 200 || |
| 144 | c >= 263 && c <= 314 || c >= 353 && c <= 359 || |
| 145 | c == 386 || c == 389: // drizzle, rain |
| 146 | return "🌧️" |
| 147 | default: |
| 148 | return "🌡️" |
| 149 | } |
| 150 | } |