package tenantsettings

import (
	"context"
	"os"
	"testing"

	"github.com/jackc/pgx/v5/pgxpool"
)

func setupTest(t *testing.T) (*Store, string, string, func()) {
	t.Helper()
	adminDSN := os.Getenv("TEST_ADMIN_DSN")
	if adminDSN == "" {
		t.Skip("TEST_ADMIN_DSN nicht gesetzt, Integrationstest uebersprungen")
	}
	ctx := context.Background()

	pool, err := pgxpool.New(ctx, adminDSN)
	if err != nil {
		t.Fatalf("pool: %v", err)
	}
	if _, err := pool.Exec(ctx, `
		CREATE TABLE IF NOT EXISTS tenants (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
			slug TEXT NOT NULL UNIQUE,
			name TEXT NOT NULL,
			db_name TEXT NOT NULL UNIQUE,
			db_dsn TEXT NOT NULL,
			status TEXT NOT NULL DEFAULT 'active',
			created_at TIMESTAMPTZ NOT NULL DEFAULT now()
		);
		CREATE TABLE IF NOT EXISTS tenant_settings (
			tenant_id UUID PRIMARY KEY REFERENCES tenants(id),
			display_name TEXT, logo_url TEXT, color_scheme TEXT, timezone TEXT, language TEXT,
			version INT NOT NULL DEFAULT 0, updated_at TIMESTAMPTZ NOT NULL DEFAULT now()
		);
		CREATE TABLE IF NOT EXISTS tenant_settings_history (
			id UUID PRIMARY KEY DEFAULT gen_random_uuid(), tenant_id UUID NOT NULL,
			display_name TEXT, logo_url TEXT, color_scheme TEXT, timezone TEXT, language TEXT,
			version INT NOT NULL, changed_at TIMESTAMPTZ NOT NULL DEFAULT now()
		);
	`); err != nil {
		t.Fatalf("schema: %v", err)
	}

	var tenantA, tenantB string
	if err := pool.QueryRow(ctx, `INSERT INTO tenants (slug, name, db_name, db_dsn) VALUES ('ts_a', 'A', 'tenant_ts_a', 'unused') RETURNING id`).Scan(&tenantA); err != nil {
		t.Fatalf("tenant a anlegen: %v", err)
	}
	if err := pool.QueryRow(ctx, `INSERT INTO tenants (slug, name, db_name, db_dsn) VALUES ('ts_b', 'B', 'tenant_ts_b', 'unused') RETURNING id`).Scan(&tenantB); err != nil {
		t.Fatalf("tenant b anlegen: %v", err)
	}

	cleanup := func() {
		_, _ = pool.Exec(ctx, `DELETE FROM tenant_settings_history WHERE tenant_id IN ($1, $2)`, tenantA, tenantB)
		_, _ = pool.Exec(ctx, `DELETE FROM tenant_settings WHERE tenant_id IN ($1, $2)`, tenantA, tenantB)
		_, _ = pool.Exec(ctx, `DELETE FROM tenants WHERE id IN ($1, $2)`, tenantA, tenantB)
		pool.Close()
	}
	return NewStore(pool), tenantA, tenantB, cleanup
}

func strp(s string) *string { return &s }

// Akzeptanzkriterium 2 + Pruefung 2: fehlende Werte liefern Defaults, kein Fehler.
func TestGet_UnsetTenantReturnsDefaults(t *testing.T) {
	store, tenantA, _, cleanup := setupTest(t)
	defer cleanup()
	ctx := context.Background()

	got, err := store.Get(ctx, tenantA)
	if err != nil {
		t.Fatalf("get: %v", err)
	}
	want := Defaults()
	if got != want {
		t.Fatalf("erwartet defaults %+v, habe %+v", want, got)
	}
}

// Akzeptanzkriterium 1 + 2: Teil-Update laesst nicht gesetzte Felder auf Default.
func TestUpdate_PartialPatchKeepsOtherFieldsAtDefault(t *testing.T) {
	store, tenantA, _, cleanup := setupTest(t)
	defer cleanup()
	ctx := context.Background()

	got, err := store.Update(ctx, tenantA, Patch{DisplayName: strp("Acme GmbH")})
	if err != nil {
		t.Fatalf("update: %v", err)
	}
	if got.DisplayName != "Acme GmbH" {
		t.Fatalf("erwartet 'Acme GmbH', habe %q", got.DisplayName)
	}
	d := Defaults()
	if got.ColorScheme != d.ColorScheme || got.Timezone != d.Timezone || got.Language != d.Language {
		t.Fatalf("nicht gesetzte felder haetten auf default bleiben sollen, habe %+v", got)
	}
	if got.Version != 1 {
		t.Fatalf("erwartet version 1, habe %d", got.Version)
	}
}

// Akzeptanzkriterium 1 + Pruefung 1: Aenderung eines Tenants wirkt sich
// nicht auf einen anderen aus.
func TestUpdate_IsolatedBetweenTenants(t *testing.T) {
	store, tenantA, tenantB, cleanup := setupTest(t)
	defer cleanup()
	ctx := context.Background()

	if _, err := store.Update(ctx, tenantA, Patch{DisplayName: strp("Tenant A")}); err != nil {
		t.Fatalf("update a: %v", err)
	}

	gotB, err := store.Get(ctx, tenantB)
	if err != nil {
		t.Fatalf("get b: %v", err)
	}
	if gotB != Defaults() {
		t.Fatalf("tenant b sollte unberuehrt bei defaults bleiben, habe %+v", gotB)
	}
}

// Akzeptanzkriterium 3: Aenderungen versioniert nachvollziehbar.
func TestUpdate_HistoryTracksVersions(t *testing.T) {
	store, tenantA, _, cleanup := setupTest(t)
	defer cleanup()
	ctx := context.Background()

	if _, err := store.Update(ctx, tenantA, Patch{DisplayName: strp("v1")}); err != nil {
		t.Fatalf("update 1: %v", err)
	}
	if _, err := store.Update(ctx, tenantA, Patch{DisplayName: strp("v2")}); err != nil {
		t.Fatalf("update 2: %v", err)
	}
	if _, err := store.Update(ctx, tenantA, Patch{ColorScheme: strp("dark")}); err != nil {
		t.Fatalf("update 3: %v", err)
	}

	history, err := store.History(ctx, tenantA)
	if err != nil {
		t.Fatalf("history: %v", err)
	}
	if len(history) != 3 {
		t.Fatalf("erwartet 3 historieneintraege, habe %d", len(history))
	}
	if history[0].DisplayName != "v1" || history[0].Version != 1 {
		t.Fatalf("history[0] unerwartet: %+v", history[0])
	}
	if history[1].DisplayName != "v2" || history[1].Version != 2 {
		t.Fatalf("history[1] unerwartet: %+v", history[1])
	}
	if history[2].ColorScheme != "dark" || history[2].DisplayName != "v2" || history[2].Version != 3 {
		t.Fatalf("history[2] unerwartet (display_name haette aus vorherigem update erhalten bleiben sollen): %+v", history[2])
	}
}