package promptinput

import (
	"encoding/json"
	"strings"
	"testing"
	"time"

	"gitea.maximumdirect.net/eric/weatherreporter/internal/briefing"
	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
)

func TestBuildDailyDataPackage(t *testing.T) {
	briefingPackage := validBriefingPackage()

	pkg, err := Build(briefingPackage)
	if err != nil {
		t.Fatalf("Build() error = %v", err)
	}

	if pkg.SchemaVersion != SchemaVersion {
		t.Fatalf("SchemaVersion = %q, want %q", pkg.SchemaVersion, SchemaVersion)
	}
	if pkg.RunID != "20260529T100000Z_daily_today" {
		t.Fatalf("RunID = %q, want briefing run id", pkg.RunID)
	}
	if pkg.Report.PromptID != "weather.daily_report" {
		t.Fatalf("PromptID = %q, want weather.daily_report", pkg.Report.PromptID)
	}
	if pkg.Briefing.Daily == nil {
		t.Fatal("Briefing.Daily = nil")
	}
	if pkg.RecentChanges.Items == nil || len(pkg.RecentChanges.Items) != 0 {
		t.Fatalf("RecentChanges.Items = %#v, want empty slice", pkg.RecentChanges.Items)
	}
}

func TestValidateRequiresFields(t *testing.T) {
	pkg, err := Build(validBriefingPackage())
	if err != nil {
		t.Fatalf("Build() error = %v", err)
	}
	pkg.RunID = ""

	err = Validate(pkg)
	if err == nil {
		t.Fatal("Validate() error = nil, want required field error")
	}
	if !strings.Contains(err.Error(), "runId") {
		t.Fatalf("error = %q, want runId context", err.Error())
	}
}

func TestBuildThreeDayDataPackage(t *testing.T) {
	briefingPackage := validBriefingPackage()
	briefingPackage.Metadata.RunID = "20260529T100000Z_three_day"
	briefingPackage.Metadata.ReportID = report.ThreeDay
	briefingPackage.Metadata.PromptID = "weather.three_day_outlook"
	briefingPackage.Daily = nil
	briefingPackage.ThreeDay = &briefing.ThreeDay{
		Days: []briefing.OutlookDay{{Date: "2026-05-29"}},
	}

	pkg, err := Build(briefingPackage)
	if err != nil {
		t.Fatalf("Build() error = %v", err)
	}

	if pkg.Report.ID != report.ThreeDay {
		t.Fatalf("Report.ID = %q, want three_day", pkg.Report.ID)
	}
	if pkg.Briefing.ThreeDay == nil {
		t.Fatal("Briefing.ThreeDay = nil")
	}
}

func TestBuildWeekendDataPackage(t *testing.T) {
	briefingPackage := validBriefingPackage()
	briefingPackage.Metadata.RunID = "20260529T100000Z_weekend"
	briefingPackage.Metadata.ReportID = report.Weekend
	briefingPackage.Metadata.PromptID = "weather.weekend_outlook"
	briefingPackage.Daily = nil
	briefingPackage.Weekend = &briefing.Weekend{
		Days: []briefing.OutlookDay{{Date: "2026-05-30"}},
	}

	pkg, err := Build(briefingPackage)
	if err != nil {
		t.Fatalf("Build() error = %v", err)
	}

	if pkg.Report.ID != report.Weekend {
		t.Fatalf("Report.ID = %q, want weekend", pkg.Report.ID)
	}
	if pkg.Briefing.Weekend == nil {
		t.Fatal("Briefing.Weekend = nil")
	}
}

func TestBuildStormDataPackage(t *testing.T) {
	briefingPackage := validBriefingPackage()
	briefingPackage.Metadata.RunID = "20260529T100000Z_storm"
	briefingPackage.Metadata.ReportID = report.Storm
	briefingPackage.Metadata.PromptID = "weather.storm_report"
	briefingPackage.Daily = nil
	briefingPackage.Storm = &briefing.Storm{
		TimingWindow: briefingPackage.Metadata.ValidPeriod,
		Hazards:      []string{"Thunderstorms"},
	}

	pkg, err := Build(briefingPackage)
	if err != nil {
		t.Fatalf("Build() error = %v", err)
	}

	if pkg.Report.ID != report.Storm {
		t.Fatalf("Report.ID = %q, want storm", pkg.Report.ID)
	}
	if pkg.Report.PromptID != "weather.storm_report" {
		t.Fatalf("PromptID = %q, want weather.storm_report", pkg.Report.PromptID)
	}
	if pkg.Briefing.Storm == nil {
		t.Fatal("Briefing.Storm = nil")
	}
}

func TestMarshalDeterministic(t *testing.T) {
	pkg, err := Build(validBriefingPackage())
	if err != nil {
		t.Fatalf("Build() error = %v", err)
	}

	first, err := json.MarshalIndent(pkg, "", "  ")
	if err != nil {
		t.Fatalf("first marshal: %v", err)
	}
	second, err := json.MarshalIndent(pkg, "", "  ")
	if err != nil {
		t.Fatalf("second marshal: %v", err)
	}
	if string(first) != string(second) {
		t.Fatalf("JSON output changed between marshals:\n%s\n---\n%s", string(first), string(second))
	}
}

func validBriefingPackage() briefing.Package {
	generatedAt := time.Date(2026, 5, 29, 10, 0, 0, 0, time.UTC)
	return briefing.Package{
		Metadata: briefing.Metadata{
			SchemaVersion: briefing.SchemaVersion,
			RunID:         "20260529T100000Z_daily_today",
			ReportID:      report.DailyToday,
			PromptID:      "weather.daily_report",
			GeneratedAt:   generatedAt,
			Units:         "us",
			Timezone:      "America/Chicago",
			ValidPeriod: timeutil.Period{
				Start: time.Date(2026, 5, 29, 5, 0, 0, 0, time.UTC),
				End:   time.Date(2026, 5, 30, 5, 0, 0, 0, time.UTC),
			},
		},
		Daily: &briefing.Daily{
			ForecastSummaryDate: "2026-05-29",
		},
	}
}