// Package module defines stable module contracts for prompt-facing stanzas.
package module

import (
	"encoding/json"
	"fmt"
)

const SnapshotSchemaVersion = "weatherreporter.modules.v1"

type ID string

const (
	Metadata                ID = "metadata"
	CurrentConditions       ID = "current_conditions"
	NarrativeForecast       ID = "narrative_forecast"
	HourlyForecast          ID = "hourly_forecast"
	DerivedDailySummary     ID = "derived_daily_summary"
	DerivedDaypartSummaries ID = "derived_daypart_summaries"
	PrecipTiming            ID = "precip_timing"
	AlertDigest             ID = "alert_digest"
	AreaForecastDiscussion  ID = "area_forecast_discussion"
	WeatherStory            ID = "weather_story"
	SPCConvectiveOutlooks   ID = "spc_convective_outlooks"
	SPCConvectiveDiscussion ID = "spc_convective_discussion"
	OutdoorWindows          ID = "outdoor_windows"
	TodayPlanning           ID = "today_planning"
	TomorrowPlanning        ID = "tomorrow_planning"
	DailyPlanning           ID = "daily_planning"
)

type ConfigItem struct {
	ID      ID  `json:"id"`
	Options any `json:"options,omitempty"`
}

type Output struct {
	ID          ID     `json:"id"`
	StanzaName  string `json:"stanzaName"`
	Value       any    `json:"value"`
	PromptValue any    `json:"-" yaml:"-"`
}

type Snapshot struct {
	SchemaVersion string   `json:"schemaVersion"`
	Outputs       []Output `json:"outputs"`
}

func (o Output) DataPackageValue() any {
	if o.PromptValue != nil {
		return o.PromptValue
	}
	return o.Value
}

func NewSnapshot(outputs []Output) (Snapshot, error) {
	snapshot := Snapshot{
		SchemaVersion: SnapshotSchemaVersion,
		Outputs:       append([]Output(nil), outputs...),
	}
	if err := snapshot.Validate(); err != nil {
		return Snapshot{}, err
	}
	return snapshot, nil
}

func (s Snapshot) Validate() error {
	if s.SchemaVersion == "" {
		return fmt.Errorf("schemaVersion is required")
	}
	seenModules := map[ID]struct{}{}
	seenStanzas := map[string]struct{}{}
	for i, output := range s.Outputs {
		if output.ID == "" {
			return fmt.Errorf("outputs[%d].id is required", i)
		}
		if output.StanzaName == "" {
			return fmt.Errorf("outputs[%d].stanzaName is required", i)
		}
		if _, ok := seenModules[output.ID]; ok {
			return fmt.Errorf("duplicate module output %q", output.ID)
		}
		seenModules[output.ID] = struct{}{}
		if _, ok := seenStanzas[output.StanzaName]; ok {
			return fmt.Errorf("duplicate stanza name %q", output.StanzaName)
		}
		seenStanzas[output.StanzaName] = struct{}{}
	}
	return nil
}

func (s Snapshot) LookupStanza(name string) (Output, bool) {
	for _, output := range s.Outputs {
		if output.StanzaName == name {
			return output, true
		}
	}
	return Output{}, false
}

func StanzaValue[T any](s Snapshot, name string) (T, bool, error) {
	var zero T
	output, ok := s.LookupStanza(name)
	if !ok {
		return zero, false, nil
	}
	data, err := json.Marshal(output.Value)
	if err != nil {
		return zero, true, fmt.Errorf("marshal stanza %q: %w", name, err)
	}
	if err := json.Unmarshal(data, &zero); err != nil {
		return zero, true, fmt.Errorf("decode stanza %q: %w", name, err)
	}
	return zero, true, nil
}

type FactRequirement string

const (
	CollectedCurrentConditions           FactRequirement = "collected.current_conditions"
	CollectedNarrativeForecast           FactRequirement = "collected.narrative_forecast"
	CollectedHourlyForecast              FactRequirement = "collected.hourly_forecast"
	CollectedAlerts                      FactRequirement = "collected.alerts"
	CollectedDiscussion                  FactRequirement = "collected.discussion"
	CollectedWeatherStory                FactRequirement = "collected.weather_story"
	CollectedSPCConvectiveOutlooks       FactRequirement = "collected.spc_convective_outlooks"
	CollectedSourceMetadata              FactRequirement = "collected.source_metadata"
	RequiresDerivedHourlyPeriods         FactRequirement = "derived.hourly_periods"
	RequiresDerivedNarrativePeriods      FactRequirement = "derived.narrative_periods"
	RequiresDerivedAlertOverlaps         FactRequirement = "derived.alert_overlaps"
	RequiresDerivedDailySummaries        FactRequirement = "derived.daily_summaries"
	RequiresDerivedDaypartSummaries      FactRequirement = "derived.daypart_summaries"
	RequiresDerivedPrecipTiming          FactRequirement = "derived.precip_timing"
	RequiresDerivedSPCConvectiveOutlooks FactRequirement = "derived.spc_convective_outlooks"
)

type MissingDataBehavior string

const (
	MissingDataOmit  MissingDataBehavior = "omit"
	MissingDataEmpty MissingDataBehavior = "empty"
	MissingDataError MissingDataBehavior = "error"
	MissingDataWarn  MissingDataBehavior = "warn"
)

type MetadataOptions struct{}
type CurrentConditionsOptions struct{}
type NarrativeForecastOptions struct{}
type HourlyForecastOptions struct{}
type DerivedDailySummaryOptions struct{}
type DerivedDaypartSummariesOptions struct{}
type PrecipTimingOptions struct{}
type AlertDigestOptions struct{}
type AreaForecastDiscussionOptions struct {
	Sections []string `json:"sections,omitempty" yaml:"sections,omitempty"`
}
type WeatherStoryOptions struct{}
type SPCConvectiveOutlooksOptions struct{}
type SPCConvectiveDiscussionOptions struct{}
type OutdoorWindowsOptions struct{}
type TodayPlanningOptions struct{}
type TomorrowPlanningOptions struct{}
type DailyPlanningOptions struct{}