package promptinput

import (
	"strings"
	"testing"
	"time"

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

func TestBuildDailyDataPackage(t *testing.T) {
	pkg, err := Build(validBuildRequest(t))
	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 metadata run id", pkg.RunID)
	}
	if pkg.Report.PromptID != "weather.daily_report" {
		t.Fatalf("PromptID = %q, want weather.daily_report", pkg.Report.PromptID)
	}
	if pkg.Report.CurrentLocalDate != "2026-05-29" {
		t.Fatalf("CurrentLocalDate = %q, want 2026-05-29", pkg.Report.CurrentLocalDate)
	}
	if pkg.Briefing.Order[0] != "metadata" || pkg.Briefing.Order[1] != "current_conditions" || pkg.Briefing.Order[2] != "derived_daily_summary" {
		t.Fatalf("Briefing.Order = %#v, want snapshot stanza order", pkg.Briefing.Order)
	}
	if got := pkg.Briefing.Values["current_conditions"].(map[string]string)["condition_text"]; got != "Partly cloudy" {
		t.Fatalf("current_conditions.condition_text = %q, want Partly cloudy", got)
	}
	if pkg.RecentChanges.Items == nil || len(pkg.RecentChanges.Items) != 0 {
		t.Fatalf("RecentChanges.Items = %#v, want empty slice", pkg.RecentChanges.Items)
	}
}

func TestBuildCurrentLocalDateUsesReportTimezone(t *testing.T) {
	req := validBuildRequest(t)
	req.Metadata.GeneratedAt = time.Date(2026, 5, 30, 2, 30, 0, 0, time.UTC)
	req.Metadata.Timezone = "America/Chicago"

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

	if pkg.Report.CurrentLocalDate != "2026-05-29" {
		t.Fatalf("CurrentLocalDate = %q, want local Chicago date 2026-05-29", pkg.Report.CurrentLocalDate)
	}
}

func TestBuildRejectsInvalidReportTimezone(t *testing.T) {
	req := validBuildRequest(t)
	req.Metadata.Timezone = "Not/AZone"

	_, err := Build(req)
	if err == nil {
		t.Fatal("Build() error = nil, want invalid timezone error")
	}
	if !strings.Contains(err.Error(), "report timezone") {
		t.Fatalf("error = %q, want report timezone context", err.Error())
	}
}

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

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

func TestBuildUsesNamedSnapshotStanzas(t *testing.T) {
	req := validBuildRequest(t)
	req.Metadata.RunID = "20260529T100000Z_three_day"
	req.Metadata.ReportID = report.ThreeDay
	req.Metadata.PromptID = "weather.three_day_outlook"
	req.Modules = snapshotWithOutputs(t,
		module.Output{ID: module.Metadata, StanzaName: "metadata", Value: map[string]string{"run_id": req.Metadata.RunID}},
		module.Output{ID: module.ForecastDelta, StanzaName: "three_day", Value: map[string]any{"days": []string{"2026-05-29"}}},
	)

	pkg, err := Build(req)
	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 _, ok := pkg.Briefing.Values["three_day"]; !ok {
		t.Fatal("Briefing.Values[three_day] missing")
	}
}

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

	first, err := MarshalYAML(pkg)
	if err != nil {
		t.Fatalf("first marshal: %v", err)
	}
	second, err := MarshalYAML(pkg)
	if err != nil {
		t.Fatalf("second marshal: %v", err)
	}
	if string(first) != string(second) {
		t.Fatalf("YAML output changed between marshals:\n%s\n---\n%s", string(first), string(second))
	}
	if !strings.Contains(string(first), "schema_version: weatherreporter.data_package.v2") ||
		!strings.Contains(string(first), "briefing:\n") ||
		!strings.Contains(string(first), "    current_conditions:\n") ||
		!strings.Contains(string(first), "        condition_text: Partly cloudy") {
		t.Fatalf("YAML output missing expected named stanzas:\n%s", string(first))
	}
}

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

	loaded, err := LoadYAML(data)
	if err != nil {
		t.Fatalf("LoadYAML() error = %v", err)
	}

	if loaded.SchemaVersion != SchemaVersion || loaded.RunID != pkg.RunID {
		t.Fatalf("loaded package = %#v, want schema and run id", loaded)
	}
	if loaded.Briefing.Order[1] != "current_conditions" {
		t.Fatalf("loaded briefing order = %#v, want current_conditions second", loaded.Briefing.Order)
	}
}

func validBuildRequest(t *testing.T) BuildRequest {
	t.Helper()
	generatedAt := time.Date(2026, 5, 29, 10, 0, 0, 0, time.UTC)
	return BuildRequest{
		Metadata: Metadata{
			RunID:       "20260529T100000Z_daily_today",
			ReportID:    report.DailyToday,
			Variant:     "today",
			PromptID:    "weather.daily_report",
			GeneratedAt: generatedAt,
			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),
			},
		},
		Modules: snapshotWithOutputs(t,
			module.Output{ID: module.Metadata, StanzaName: "metadata", Value: map[string]string{"run_id": "20260529T100000Z_daily_today"}},
			module.Output{ID: module.CurrentConditions, StanzaName: "current_conditions", Value: map[string]string{"condition_text": "Partly cloudy"}},
			module.Output{ID: module.DerivedDailySummary, StanzaName: "derived_daily_summary", Value: map[string]string{"date": "2026-05-29"}},
		),
	}
}

func snapshotWithOutputs(t *testing.T, outputs ...module.Output) module.Snapshot {
	t.Helper()
	snapshot, err := module.NewSnapshot(outputs)
	if err != nil {
		t.Fatalf("NewSnapshot() error = %v", err)
	}
	return snapshot
}