package cli

import (
	"bytes"
	"context"
	"io"
	"log/slog"
	"os"
	"path/filepath"
	"strings"
	"testing"

	"github.com/mithral/vellum/internal/auth"
	"github.com/mithral/vellum/internal/core"
)

// testConfig points a Config at a fresh database inside a temp dir. The CLI
// itself opens and migrates it, mirroring the auth_test.go setup pattern.
func testConfig(t *testing.T) core.Config {
	t.Helper()
	return core.Config{DBPath: filepath.Join(t.TempDir(), "vellum.db")}
}

func testLogger() *slog.Logger {
	return slog.New(slog.NewTextHandler(io.Discard, nil))
}

// runCapturing runs the exported entrypoint with os.Stdout redirected so the
// subcommand's output can be asserted on.
func runCapturing(t *testing.T, args []string, cfg core.Config, log *slog.Logger) (string, bool, error) {
	t.Helper()

	old := os.Stdout
	r, w, err := os.Pipe()
	if err != nil {
		t.Fatalf("pipe: %v", err)
	}
	os.Stdout = w

	handled, runErr := Run(args, cfg, log)

	os.Stdout = old
	if err := w.Close(); err != nil {
		t.Fatalf("close stdout pipe: %v", err)
	}
	out, err := io.ReadAll(r)
	if err != nil {
		t.Fatalf("read stdout: %v", err)
	}
	_ = r.Close()
	return string(out), handled, runErr
}

func TestRunUserAddAndList(t *testing.T) {
	cfg := testConfig(t)
	log := testLogger()

	if _, handled, err := runCapturing(t, []string{"user", "add", "alice", "password123"}, cfg, log); !handled || err != nil {
		t.Fatalf("user add alice: handled=%v err=%v", handled, err)
	}
	if _, handled, err := runCapturing(t, []string{"user", "add", "root", "password123", "--admin"}, cfg, log); !handled || err != nil {
		t.Fatalf("user add root --admin: handled=%v err=%v", handled, err)
	}

	out, handled, err := runCapturing(t, []string{"user", "list"}, cfg, log)
	if !handled {
		t.Fatal("user list was not handled")
	}
	if err != nil {
		t.Fatalf("user list: %v", err)
	}

	lines := strings.Split(strings.TrimSpace(out), "\n")
	if len(lines) != 2 {
		t.Fatalf("user list printed %d lines, want 2:\n%s", len(lines), out)
	}
	if !strings.Contains(lines[0], "alice") || strings.Contains(lines[0], "admin=true") {
		t.Errorf("alice line = %q, want non-admin alice", lines[0])
	}
	if !strings.Contains(lines[1], "root") || !strings.Contains(lines[1], "admin=true") {
		t.Errorf("root line = %q, want admin root", lines[1])
	}

	// The password written through the CLI must actually authenticate.
	db, err := core.OpenDB(cfg.DBPath)
	if err != nil {
		t.Fatalf("reopen db: %v", err)
	}
	defer db.Close()
	if _, err := auth.Authenticate(context.Background(), db, "alice", "password123"); err != nil {
		t.Fatalf("alice cannot authenticate after CLI add: %v", err)
	}
}

func TestRunUserPasswd(t *testing.T) {
	cfg := testConfig(t)
	log := testLogger()
	ctx := context.Background()

	if _, handled, err := runCapturing(t, []string{"user", "add", "bob", "oldpassword"}, cfg, log); !handled || err != nil {
		t.Fatalf("user add bob: handled=%v err=%v", handled, err)
	}

	// The password change goes through GetUserByUsername + SetPassword.
	if _, handled, err := runCapturing(t, []string{"user", "passwd", "bob", "newpassword"}, cfg, log); !handled || err != nil {
		t.Fatalf("user passwd bob: handled=%v err=%v", handled, err)
	}

	db, err := core.OpenDB(cfg.DBPath)
	if err != nil {
		t.Fatalf("reopen db: %v", err)
	}
	defer db.Close()
	if _, err := auth.Authenticate(ctx, db, "bob", "newpassword"); err != nil {
		t.Fatalf("new password does not authenticate: %v", err)
	}
	if _, err := auth.Authenticate(ctx, db, "bob", "oldpassword"); err == nil {
		t.Error("old password still authenticates after passwd")
	}

	// Unknown users are reported cleanly rather than as sql.ErrNoRows.
	if _, handled, err := runCapturing(t, []string{"user", "passwd", "nobody", "whatever"}, cfg, log); !handled || err == nil {
		t.Errorf("passwd for unknown user: handled=%v err=%v, want handled error", handled, err)
	}
}

func TestRunBackup(t *testing.T) {
	cfg := testConfig(t)
	log := testLogger()
	ctx := context.Background()

	// Seed a row so the backup has something to carry across.
	if _, handled, err := runCapturing(t, []string{"user", "add", "carol", "password123"}, cfg, log); !handled || err != nil {
		t.Fatalf("user add carol: handled=%v err=%v", handled, err)
	}

	dest := filepath.Join(t.TempDir(), "backup.db")
	handled, err := run(ctx, []string{"backup", dest}, cfg, log, io.Discard)
	if !handled {
		t.Fatal("backup was not handled")
	}
	if err != nil {
		t.Fatalf("backup: %v", err)
	}

	info, err := os.Stat(dest)
	if err != nil {
		t.Fatalf("stat backup: %v", err)
	}
	if info.Size() == 0 {
		t.Fatal("backup file is empty")
	}

	// The backup must be a complete, independently usable database.
	bdb, err := core.OpenDB(dest)
	if err != nil {
		t.Fatalf("open backup: %v", err)
	}
	defer bdb.Close()
	if _, err := auth.GetUserByUsername(ctx, bdb, "carol"); err != nil {
		t.Fatalf("backup is missing the seeded user: %v", err)
	}
}

func TestRunUnhandled(t *testing.T) {
	cfg := testConfig(t)
	var buf bytes.Buffer

	handled, err := run(context.Background(), []string{"serve"}, cfg, testLogger(), &buf)
	if handled {
		t.Error("unknown command reported handled=true")
	}
	if err != nil {
		t.Errorf("unknown command returned error: %v", err)
	}

	handled, err = run(context.Background(), nil, cfg, testLogger(), &buf)
	if handled || err != nil {
		t.Errorf("empty args: handled=%v err=%v, want false,nil", handled, err)
	}
}