Add hourly generated text contract

internal/generatedtext/hourly.go

@@ -0,0 +1,55 @@
+// Package generatedtext validates structured LLM text and render contexts.
+package generatedtext
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"strings"
+)
+
+type Hourly struct {
+	Summary    string `json:"summary"`
+	Timing     string `json:"timing"`
+	Impacts    string `json:"impacts"`
+	Confidence string `json:"confidence,omitempty"`
+}
+
+func ValidateHourly(data []byte) (Hourly, []byte, error) {
+	decoder := json.NewDecoder(bytes.NewReader(data))
+	decoder.DisallowUnknownFields()
+
+	var value Hourly
+	if err := decoder.Decode(&value); err != nil {
+		return Hourly{}, nil, fmt.Errorf("decode hourly generated text: %w", err)
+	}
+	var extra any
+	if err := decoder.Decode(&extra); err != nil {
+		if err != io.EOF {
+			return Hourly{}, nil, fmt.Errorf("decode hourly generated text: %w", err)
+		}
+	} else {
+		return Hourly{}, nil, fmt.Errorf("decode hourly generated text: multiple JSON values")
+	}
+
+	value.Summary = strings.TrimSpace(value.Summary)
+	value.Timing = strings.TrimSpace(value.Timing)
+	value.Impacts = strings.TrimSpace(value.Impacts)
+	value.Confidence = strings.TrimSpace(value.Confidence)
+	if value.Summary == "" {
+		return Hourly{}, nil, fmt.Errorf("hourly generated text summary is required")
+	}
+	if value.Timing == "" {
+		return Hourly{}, nil, fmt.Errorf("hourly generated text timing is required")
+	}
+	if value.Impacts == "" {
+		return Hourly{}, nil, fmt.Errorf("hourly generated text impacts is required")
+	}
+
+	normalized, err := json.Marshal(value)
+	if err != nil {
+		return Hourly{}, nil, fmt.Errorf("normalize hourly generated text: %w", err)
+	}
+	return value, normalized, nil
+}