package app

import (
	"bytes"
	"reflect"
	"testing"

	"gitea.maximumdirect.net/eric/weatherreporter/internal/collect"
	"gitea.maximumdirect.net/eric/weatherreporter/internal/weatherdata"
)

func TestPrepareReportBuildsImmutableDeterministicInputs(t *testing.T) {
	cfg := generationConfig()
	bundle := generationBundle(t)
	resolved, err := ResolveGenerate(GenerateRequest{
		Config: cfg, Report: ReportDaily,
		Date: generationTime("2026-05-29T12:00:00-05:00"), Now: generationTime("2026-05-29T08:30:00-05:00"),
	}, generationTime("2026-05-29T08:30:00-05:00"))
	if err != nil {
		t.Fatalf("ResolveGenerate() error = %v", err)
	}

	request := prepareReportRequest{Config: cfg, Resolved: resolved, Collection: collect.Result{Bundle: &bundle}}
	prepared, err := prepareReport(request)
	if err != nil {
		t.Fatalf("prepareReport() error = %v", err)
	}
	repeated, err := prepareReport(request)
	if err != nil {
		t.Fatalf("second prepareReport() error = %v", err)
	}
	if len(prepared.dataPackage) == 0 || !bytes.Equal(prepared.dataPackage, repeated.dataPackage) || !reflect.DeepEqual(prepared.briefingMetadata, repeated.briefingMetadata) {
		t.Fatalf("prepared package/metadata are not deterministic: %q/%#v", prepared.dataPackage, prepared.briefingMetadata)
	}

	originalDataPackage := append([]byte(nil), prepared.dataPackage...)
	originalMetadata := prepared.briefingMetadata
	originalWarnings := append([]weatherdata.SourceWarning(nil), prepared.sourceWarnings...)
	metadata, snapshot, reportFacts, err := prepared.renderInputs()
	if err != nil {
		t.Fatalf("renderInputs() error = %v", err)
	}
	metadata.SourceWarnings = append(metadata.SourceWarnings, weatherdata.SourceWarning{Source: "test", Message: "consumer mutation"})
	snapshot.Outputs = nil
	reportFacts.Collected.Hourly.Periods[0].TextDescription = "consumer mutation"
	bundle.Hourly.Periods[0].TextDescription = "mutated after preparation"
	bundle.Warnings = append(bundle.Warnings, weatherdata.SourceWarning{Source: "test", Message: "mutated warning"})
	if len(bundle.Sources) > 0 {
		if bundle.Sources[0].Query == nil {
			bundle.Sources[0].Query = map[string]string{}
		}
		bundle.Sources[0].Query["mutated"] = "true"
	}

	if !bytes.Equal(prepared.dataPackage, originalDataPackage) || !reflect.DeepEqual(prepared.briefingMetadata, originalMetadata) || !reflect.DeepEqual(prepared.sourceWarnings, originalWarnings) {
		t.Fatalf("prepared values changed after caller mutation: %#v", prepared)
	}
	if prepared.reportFacts.Collected.Hourly.Periods[0].TextDescription == "mutated after preparation" {
		t.Fatal("prepared report facts retain caller-owned weather data")
	}
	if prepared.reportFacts.Collected.Hourly.Periods[0].TextDescription == "consumer mutation" || len(prepared.moduleSnapshot.Outputs) == 0 {
		t.Fatal("prepared report values retain consumer mutation")
	}
}