package backup_test

import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"io"
	"log/slog"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"strings"
	"sync"
	"testing"
	"time"

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

	"git.fabledsword.com/bvandeusen/minstrel/internal/backup"
)

func newService(t *testing.T) (*backup.Service, *pgxpool.Pool) {
	t.Helper()
	pool := newPool(t)
	svc := backup.NewService(pool, slog.New(slog.NewTextHandler(io.Discard, nil)), "test-build")
	t.Cleanup(svc.Close)
	return svc, pool
}

// waitIdle waits for the running backup to finish, for at most 30 seconds.
func waitIdle(t *testing.T, svc *backup.Service) {
	t.Helper()
	deadline := time.Now().Add(30 * time.Second)
	for !svc.Running().IsZero() {
		if time.Now().After(deadline) {
			t.Fatal("the backup is still running after 30s")
		}
		time.Sleep(20 * time.Millisecond)
	}
}

func status(t *testing.T, svc *backup.Service) backup.Status {
	t.Helper()
	st, err := svc.Status(context.Background())
	if err != nil {
		t.Fatal(err)
	}
	return st
}

func TestABackupIsOffAndRefusesToStartUntilSetUp_Integration(t *testing.T) {
	svc, _ := newService(t)
	st := status(t, svc)
	if st.State != backup.StateOff || st.Config.Enabled || st.NextRun != nil || len(st.Runs) != 0 {
		t.Errorf("a fresh server's backup = %+v, want off with no runs", st)
	}
	if err := svc.Start(context.Background(), backup.TriggerManual); !errors.Is(err, backup.ErrNotReady) {
		t.Errorf("Start = %v, want ErrNotReady", err)
	}
	if err := svc.Save(context.Background(), backup.Update{Enabled: true, Destination: backup.DestinationS3, RunHour: 3}); err != nil {
		t.Fatal(err)
	}
	if st := status(t, svc); st.State != backup.StateIncomplete || len(st.Problems) != 4 {
		t.Errorf("switched on with no bucket: %s %v", st.State, st.Problems)
	}
}

func TestABackupRunsIntoAFolder_Integration(t *testing.T) {
	svc, _ := newService(t)
	dir := t.TempDir()
	ctx := context.Background()
	if err := svc.Save(ctx, backup.Update{Enabled: true, Destination: backup.DestinationFolder, Folder: dir, RunHour: 3}); err != nil {
		t.Fatal(err)
	}
	if st := status(t, svc); st.State != backup.StateWaiting || st.NextRun == nil {
		t.Errorf("set up, never run: %s next %v", st.State, st.NextRun)
	}
	if err := svc.Start(ctx, backup.TriggerManual); err != nil {
		t.Fatal(err)
	}
	waitIdle(t, svc)

	st := status(t, svc)
	if st.State != backup.StateOK || len(st.Runs) != 1 || st.LastSuccess == nil {
		t.Fatalf("after a run: %+v", st)
	}
	run := st.Runs[0]
	if run.Status != "succeeded" || run.Trigger != backup.TriggerManual || run.FinishedAt == nil ||
		filepath.Dir(run.Location) != filepath.Join(dir, "database") || run.Error != "" {
		t.Fatalf("run = %+v", run)
	}
	f, err := os.Open(run.Location)
	if err != nil {
		t.Fatal(err)
	}
	defer func() { _ = f.Close() }()
	info, _ := f.Stat()
	if info.Size() != run.Bytes {
		t.Errorf("recorded %d bytes, the file holds %d", run.Bytes, info.Size())
	}
	m, _, err := backup.Read(f)
	if err != nil || m.Build != "test-build" {
		t.Errorf("the backup reads back as %+v, %v", m, err)
	}

	res, err := svc.Test(ctx, backup.Update{Destination: backup.DestinationFolder, Folder: dir, RunHour: 3})
	if err != nil || res.Backups != 1 || res.Latest == nil {
		t.Errorf("Test = %+v, %v; want the one backup", res, err)
	}
}

func TestAMissingFolderFailsTheRunAndSaysSo_Integration(t *testing.T) {
	svc, _ := newService(t)
	ctx := context.Background()
	missing := filepath.Join(t.TempDir(), "not-mounted")
	if err := svc.Save(ctx, backup.Update{Enabled: true, Destination: backup.DestinationFolder, Folder: missing, RunHour: 3}); err != nil {
		t.Fatal(err)
	}
	if _, err := svc.Test(ctx, backup.Update{Destination: backup.DestinationFolder, Folder: missing}); err == nil {
		t.Error("Test passed on a missing folder")
	}
	if err := svc.Start(ctx, backup.TriggerManual); err != nil {
		t.Fatal(err)
	}
	waitIdle(t, svc)
	st := status(t, svc)
	if st.State != backup.StateFailing || st.FailingSince == nil || len(st.Runs) != 1 ||
		!strings.Contains(st.Runs[0].Error, "isn't there") {
		t.Errorf("after a failed run: %s %+v", st.State, st.Runs)
	}
	if _, err := os.Stat(missing); !os.IsNotExist(err) {
		t.Error("the run created the missing folder")
	}
}

// fakeBucket answers PUTs and lists like an S3 bucket. While hold is open a
// PUT waits on it.
type fakeBucket struct {
	mu   sync.Mutex
	puts map[string][]byte
	hold chan struct{}
}

func (b *fakeBucket) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	if !strings.HasPrefix(r.Header.Get("Authorization"), "AWS4-HMAC-SHA256 Credential=ak/") {
		w.WriteHeader(http.StatusForbidden)
		return
	}
	switch r.Method {
	case http.MethodPut:
		if b.hold != nil {
			<-b.hold
		}
		body, _ := io.ReadAll(r.Body)
		b.mu.Lock()
		b.puts[r.URL.Path] = body
		b.mu.Unlock()
	case http.MethodGet:
		b.mu.Lock()
		defer b.mu.Unlock()
		_, _ = fmt.Fprint(w, `<ListBucketResult><IsTruncated>false</IsTruncated>`)
		for p, body := range b.puts {
			_, _ = fmt.Fprintf(w, `<Contents><Key>%s</Key><Size>%d</Size><LastModified>2026-11-02T03:00:05.000Z</LastModified></Contents>`,
				strings.TrimPrefix(p, "/minstrel/"), len(body))
		}
		_, _ = fmt.Fprint(w, `</ListBucketResult>`)
	}
}

func bucketUpdate(endpoint string) backup.Update {
	return backup.Update{Enabled: true, Destination: backup.DestinationS3, Endpoint: endpoint,
		Bucket: "minstrel", AccessKey: "ak", SecretKey: "sk", RunHour: 3}
}

func TestABackupRunsIntoABucket_Integration(t *testing.T) {
	svc, pool := newService(t)
	fake := &fakeBucket{puts: map[string][]byte{}}
	srv := httptest.NewServer(fake)
	defer srv.Close()
	ctx := context.Background()

	if err := svc.Save(ctx, bucketUpdate(srv.URL)); err != nil {
		t.Fatal(err)
	}
	var stored string
	if err := pool.QueryRow(ctx, "SELECT secret_key FROM backup_settings").Scan(&stored); err != nil {
		t.Fatal(err)
	}
	if !strings.HasPrefix(stored, "v1.") {
		t.Fatalf("the secret key is stored as %q, want it sealed", stored)
	}
	if cfg, _ := svc.Config(ctx); !cfg.HasSecretKey {
		t.Error("the config doesn't say a secret key is stored")
	}
	if err := svc.Start(ctx, backup.TriggerManual); err != nil {
		t.Fatal(err)
	}
	waitIdle(t, svc)

	st := status(t, svc)
	if st.State != backup.StateOK || len(st.Runs) != 1 || st.Runs[0].Status != "succeeded" {
		t.Fatalf("after a run: %s %+v", st.State, st.Runs)
	}
	key := st.Runs[0].Location
	if !strings.HasPrefix(key, "database/minstrel-") || !backup.IsFileName(filepath.Base(key)) {
		t.Errorf("stored under %q", key)
	}
	fake.mu.Lock()
	body := fake.puts["/minstrel/"+key]
	fake.mu.Unlock()
	if int64(len(body)) != st.Runs[0].Bytes {
		t.Errorf("the bucket got %d bytes, the run recorded %d", len(body), st.Runs[0].Bytes)
	}
	if _, _, err := backup.Read(bytes.NewReader(body)); err != nil {
		t.Errorf("the uploaded backup doesn't read: %v", err)
	}

	// The test sends no secret key: it uses the stored one, and only lists.
	u := bucketUpdate(srv.URL)
	u.SecretKey = ""
	res, err := svc.Test(ctx, u)
	if err != nil || res.Backups != 1 {
		t.Errorf("Test = %+v, %v; want the one backup", res, err)
	}
	fake.mu.Lock()
	defer fake.mu.Unlock()
	if len(fake.puts) != 1 {
		t.Errorf("the test wrote to the bucket: %d objects", len(fake.puts))
	}
}

func TestOneBackupAtATime_Integration(t *testing.T) {
	svc, _ := newService(t)
	fake := &fakeBucket{puts: map[string][]byte{}, hold: make(chan struct{})}
	srv := httptest.NewServer(fake)
	defer srv.Close()
	ctx := context.Background()
	if err := svc.Save(ctx, bucketUpdate(srv.URL)); err != nil {
		t.Fatal(err)
	}
	if err := svc.Start(ctx, backup.TriggerManual); err != nil {
		t.Fatal(err)
	}
	if err := svc.Start(ctx, backup.TriggerManual); !errors.Is(err, backup.ErrRunning) {
		t.Errorf("a second Start = %v, want ErrRunning", err)
	}
	if st := status(t, svc); st.RunningSince == nil {
		t.Error("the status doesn't say a backup is running")
	}
	close(fake.hold)
	waitIdle(t, svc)
}

func TestRecoverFailsARunTheLastShutdownCutOff_Integration(t *testing.T) {
	svc, pool := newService(t)
	ctx := context.Background()
	if _, err := pool.Exec(ctx, "INSERT INTO backup_runs (trigger) VALUES ('schedule')"); err != nil {
		t.Fatal(err)
	}
	svc.Recover(ctx)
	st := status(t, svc)
	if len(st.Runs) != 1 || st.Runs[0].Status != "failed" || st.Runs[0].FinishedAt == nil ||
		!strings.Contains(st.Runs[0].Error, "server stopped") {
		t.Errorf("runs = %+v", st.Runs)
	}
}

func TestSaveRefusesABadValueAndKeepsTheOldSettings_Integration(t *testing.T) {
	svc, _ := newService(t)
	ctx := context.Background()
	err := svc.Save(ctx, backup.Update{Enabled: true, Destination: backup.DestinationFolder, Folder: "relative/path"})
	var fe *backup.FieldError
	if !errors.As(err, &fe) || fe.Field != "folder" {
		t.Fatalf("err = %v, want a FieldError on folder", err)
	}
	if cfg, _ := svc.Config(ctx); cfg.Enabled || cfg.Folder != "" {
		t.Errorf("a refused save changed the settings: %+v", cfg)
	}
}