Codespace organic guide xjp9vj47vr26pqx

build.gradle

@@ -20,6 +20,8 @@ dependencies {
 
     // LangChain4j core - used for PromptTemplate (no external API key required)
     implementation 'dev.langchain4j:langchain4j:0.35.0'
+    // LangChain4j Google Gemini (direct Gemini API via Google AI Studio)
+    implementation 'dev.langchain4j:langchain4j-google-ai-gemini:0.35.0'
 
     testImplementation 'org.springframework.boot:spring-boot-starter-test'
 }

src/main/java/com/example/weatherapp/ai/AiSummaryService.java

@@ -0,0 +1,85 @@
+package com.example.weatherapp.ai;
+
+import com.example.weatherapp.weather.WeatherService.WeatherReport;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import dev.langchain4j.model.chat.ChatLanguageModel;
+import dev.langchain4j.model.googleai.GoogleAiGeminiChatModel;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Service;
+
+import java.util.Objects;
+
+@Service
+public class AiSummaryService {
+
+    private final String apiKey;
+    private final String modelName;
+    private final ObjectMapper mapper = new ObjectMapper();
+
+    private volatile ChatLanguageModel cachedModel;
+
+    public AiSummaryService(
+            @Value("${ai.gemini.api-key:}") String apiKey,
+            @Value("${ai.gemini.model:gemini-1.5-flash}") String modelName
+    ) {
+        this.apiKey = apiKey == null ? "" : apiKey.trim();
+        this.modelName = (modelName == null || modelName.isBlank()) ? "gemini-1.5-flash" : modelName;
+    }
+
+    public boolean isConfigured() {
+        return apiKey != null && !apiKey.isBlank();
+    }
+
+    public String summarize(WeatherReport report, String timezone, String city) {
+        if (!isConfigured()) {
+            return "AI summary unavailable: missing Google Gemini API key.";
+        }
+        ChatLanguageModel model = getModel();
+        String reportJson;
+        try {
+            reportJson = mapper.writeValueAsString(report);
+        } catch (JsonProcessingException e) {
+            reportJson = safeReport(report);
+        }
+
+        String location = city != null && !city.isBlank() ? city : "the provided coordinates";
+        String tz = timezone != null ? timezone : "auto";
+
+        String prompt = "You are an assistant that summarizes short-term weather forecasts for lay people.\n" +
+                "Given the JSON weather report from Open-Meteo (hourly arrays for next ~72 hours) and context, provide:\n" +
+                "1) A concise overview of the upcoming weather for the next 1-3 days in " + location + " (timezone: " + tz + ").\n" +
+                "2) Practical tips.\n" +
+                "3) 3-5 activity suggestions suited to the conditions (indoor/outdoor).\n" +
+                "Be specific about temperature ranges, precipitation likelihood, wind, and humidity.\n" +
+                "Keep it under 180 words, use short paragraphs and bullet points.\n\n" +
+                "Weather JSON:\n" + reportJson + "\n\n" +
+                "Respond in plain text (no JSON).";
+
+        try {
+            return model.generate(prompt);
+        } catch (RuntimeException ex) {
+            return "AI summary unavailable at the moment. Reason: " + ex.getMessage();
+        }
+    }
+
+    private String safeReport(WeatherReport r) {
+        try { return mapper.writeValueAsString(r); } catch (Exception e) { return "{}"; }
+    }
+
+    private ChatLanguageModel getModel() {
+        ChatLanguageModel m = cachedModel;
+        if (m == null) {
+            synchronized (this) {
+                m = cachedModel;
+                if (m == null) {
+                    cachedModel = m = GoogleAiGeminiChatModel.builder()
+                            .apiKey(apiKey)
+                            .modelName(modelName)
+                            .build();
+                }
+            }
+        }
+        return m;
+    }
+}

src/main/java/com/example/weatherapp/weather/WeatherService.java

@@ -32,15 +32,15 @@ public WeatherReport fetchHourlyReport(double lat, double lon) {
                         "temperature_2m",
                         "precipitation",
                         "wind_speed_10m",
-                        "relative_humidity_2m"
-                ))
+                        "relative_humidity_2m"))
                 .queryParam("forecast_days", 3)
                 .queryParam("timezone", "auto")
                 .toUriString();
 
         ResponseEntity<Map> resp = restTemplate.getForEntity(url, Map.class);
         Map body = resp.getBody();
-        if (body == null) throw new IllegalStateException("Empty response from weather API");
+        if (body == null)
+            throw new IllegalStateException("Empty response from weather API");
 
         // Map response into our DTO
         WeatherReport report = new WeatherReport();
@@ -52,11 +52,13 @@ public WeatherReport fetchHourlyReport(double lat, double lon) {
         if (!(hourlyObj instanceof Map<?, ?> hourly)) {
             throw new IllegalStateException("Unexpected response: missing hourly");
         }
-        report.setTimes(asStringList(hourly.get("time")));
-        report.setTemperature2m(asDoubleList(hourly.get("temperature_2m")));
-        report.setPrecipitation(asDoubleList(hourly.get("precipitation")));
-        report.setWindSpeed10m(asDoubleList(hourly.get("wind_speed_10m")));
-        report.setRelativeHumidity2m(asDoubleList(hourly.get("relative_humidity_2m")));
+        WeatherReport.Hourly hourlyData = new WeatherReport.Hourly();
+        hourlyData.setTime(asStringList(hourly.get("time")));
+        hourlyData.setTemperature2m(asDoubleList(hourly.get("temperature_2m")));
+        hourlyData.setPrecipitation(asDoubleList(hourly.get("precipitation")));
+        hourlyData.setWindSpeed10m(asDoubleList(hourly.get("wind_speed_10m")));
+        hourlyData.setRelativeHumidity2m(asDoubleList(hourly.get("relative_humidity_2m")));
+        report.setHourly(hourlyData);
 
         return report;
     }
@@ -72,45 +74,113 @@ private static List<String> asStringList(Object o) {
 
     @SuppressWarnings("unchecked")
     private static List<Double> asDoubleList(Object o) {
-        if (o == null) return null;
+        if (o == null)
+            return null;
         return ((List<?>) o).stream().map(WeatherService::asDouble).toList();
     }
 
     private static Double asDouble(Object o) {
-        if (o == null) return null;
-        if (o instanceof Number n) return n.doubleValue();
-        try { return Double.parseDouble(String.valueOf(o)); } catch (Exception e) { return null; }
+        if (o == null)
+            return null;
+        if (o instanceof Number n)
+            return n.doubleValue();
+        try {
+            return Double.parseDouble(String.valueOf(o));
+        } catch (Exception e) {
+            return null;
+        }
     }
 
     @JsonIgnoreProperties(ignoreUnknown = true)
     public static class WeatherReport {
         private Double latitude;
         private Double longitude;
         private String timezone;
-        private List<String> times;
-        @JsonProperty("temperature_2m")
-        private List<Double> temperature2m;
-        private List<Double> precipitation;
-        @JsonProperty("wind_speed_10m")
-        private List<Double> windSpeed10m;
-        @JsonProperty("relative_humidity_2m")
-        private List<Double> relativeHumidity2m;
-
-        public Double getLatitude() { return latitude; }
-        public void setLatitude(Double latitude) { this.latitude = latitude; }
-        public Double getLongitude() { return longitude; }
-        public void setLongitude(Double longitude) { this.longitude = longitude; }
-        public String getTimezone() { return timezone; }
-        public void setTimezone(String timezone) { this.timezone = timezone; }
-        public List<String> getTimes() { return times; }
-        public void setTimes(List<String> times) { this.times = times; }
-        public List<Double> getTemperature2m() { return temperature2m; }
-        public void setTemperature2m(List<Double> temperature2m) { this.temperature2m = temperature2m; }
-        public List<Double> getPrecipitation() { return precipitation; }
-        public void setPrecipitation(List<Double> precipitation) { this.precipitation = precipitation; }
-        public List<Double> getWindSpeed10m() { return windSpeed10m; }
-        public void setWindSpeed10m(List<Double> windSpeed10m) { this.windSpeed10m = windSpeed10m; }
-        public List<Double> getRelativeHumidity2m() { return relativeHumidity2m; }
-        public void setRelativeHumidity2m(List<Double> relativeHumidity2m) { this.relativeHumidity2m = relativeHumidity2m; }
+        private Hourly hourly;
+
+        public Double getLatitude() {
+            return latitude;
+        }
+
+        public void setLatitude(Double latitude) {
+            this.latitude = latitude;
+        }
+
+        public Double getLongitude() {
+            return longitude;
+        }
+
+        public void setLongitude(Double longitude) {
+            this.longitude = longitude;
+        }
+
+        public String getTimezone() {
+            return timezone;
+        }
+
+        public void setTimezone(String timezone) {
+            this.timezone = timezone;
+        }
+
+        public Hourly getHourly() {
+            return hourly;
+        }
+
+        public void setHourly(Hourly hourly) {
+            this.hourly = hourly;
+        }
+
+        // Nested class to match the "hourly" object structure
+        @JsonIgnoreProperties(ignoreUnknown = true)
+        public static class Hourly {
+            private List<String> time;
+            @JsonProperty("temperature_2m")
+            private List<Double> temperature2m;
+            private List<Double> precipitation;
+            @JsonProperty("wind_speed_10m")
+            private List<Double> windSpeed10m;
+            @JsonProperty("relative_humidity_2m")
+            private List<Double> relativeHumidity2m;
+
+            public List<String> getTime() {
+                return time;
+            }
+
+            public void setTime(List<String> time) {
+                this.time = time;
+            }
+
+            public List<Double> getTemperature2m() {
+                return temperature2m;
+            }
+
+            public void setTemperature2m(List<Double> temperature2m) {
+                this.temperature2m = temperature2m;
+            }
+
+            public List<Double> getPrecipitation() {
+                return precipitation;
+            }
+
+            public void setPrecipitation(List<Double> precipitation) {
+                this.precipitation = precipitation;
+            }
+
+            public List<Double> getWindSpeed10m() {
+                return windSpeed10m;
+            }
+
+            public void setWindSpeed10m(List<Double> windSpeed10m) {
+                this.windSpeed10m = windSpeed10m;
+            }
+
+            public List<Double> getRelativeHumidity2m() {
+                return relativeHumidity2m;
+            }
+
+            public void setRelativeHumidity2m(List<Double> relativeHumidity2m) {
+                this.relativeHumidity2m = relativeHumidity2m;
+            }
+        }
     }
 }

src/main/java/com/example/weatherapp/web/AiSummaryController.java

@@ -0,0 +1,40 @@
+package com.example.weatherapp.web;
+
+import com.example.weatherapp.ai.AiSummaryService;
+import com.example.weatherapp.weather.WeatherService.WeatherReport;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+import java.util.Map;
+
+@RestController
+@RequestMapping("/api/ai-summary")
+public class AiSummaryController {
+
+    private final AiSummaryService aiSummaryService;
+
+    public AiSummaryController(AiSummaryService aiSummaryService) {
+        this.aiSummaryService = aiSummaryService;
+    }
+
+    @PostMapping(consumes = MediaType.APPLICATION_JSON_VALUE, produces = MediaType.APPLICATION_JSON_VALUE)
+    public ResponseEntity<?> summarize(@RequestBody WeatherReport report,
+                                       @RequestParam(value = "timezone", required = false) String timezone,
+                                       @RequestParam(value = "city", required = false) String city) {
+        try {
+            String text = aiSummaryService.summarize(report, timezone, city);
+            return ResponseEntity.ok(Map.of(
+                    "summary", text,
+                    "model", "gemini",
+                    "configured", aiSummaryService.isConfigured()
+            ));
+        } catch (Exception e) {
+            return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body(Map.of(
+                    "summary", "AI summary failed.",
+                    "error", e.getMessage()
+            ));
+        }
+    }
+}

src/main/resources/application.properties

@@ -1,3 +1,8 @@
 spring.application.name=weather-app-java
 server.port=8080
 spring.thymeleaf.cache=false
+
+# Google Gemini API configuration (Google AI Studio / Generative Language API)
+# Provide via environment variable for security in production
+ai.gemini.api-key=${AI_API_KEY:}
+ai.gemini.model=${GOOGLE_GEMINI_MODEL:gemini-1.5-flash}