// 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"`
	ForecastDiscussion  string `json:"forecast_discussion"`
	PrecipitationTiming string `json:"precipitation_timing,omitempty"`
	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.ForecastDiscussion = strings.TrimSpace(value.ForecastDiscussion)
	value.PrecipitationTiming = strings.TrimSpace(value.PrecipitationTiming)
	value.Confidence = strings.TrimSpace(value.Confidence)
	if value.Summary == "" {
		return Hourly{}, nil, fmt.Errorf("hourly generated text summary is required")
	}
	if value.ForecastDiscussion == "" {
		return Hourly{}, nil, fmt.Errorf("hourly generated text forecast discussion 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
}