package backup

import (
	"context"
	"os"
	"path/filepath"
	"testing"
	"time"

	"jarl/internal/store"
)

func newDB(t *testing.T) string {
	t.Helper()
	path := filepath.Join(t.TempDir(), "jarl.db")
	st, err := store.Open(path)
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { st.Close() })
	return path
}

func TestWriteVerifyInspect(t *testing.T) {
	ctx := context.Background()
	src := newDB(t)
	dir := filepath.Join(t.TempDir(), "backups")
	now := time.Date(2026, 10, 8, 3, 15, 12, 0, time.UTC)
	f, err := Write(ctx, src, dir, KindJarl, now)
	if err != nil {
		t.Fatal(err)
	}
	if filepath.Base(f.Path) != "jarl-20261008T031512Z.db" || f.Size == 0 {
		t.Errorf("backup = %+v", f)
	}
	if fi, _ := os.Stat(f.Path); fi.Mode().Perm() != 0o600 {
		t.Errorf("mode %v", fi.Mode())
	}
	if err := Verify(ctx, f.Path); err != nil {
		t.Error(err)
	}
	in, err := Inspect(ctx, f.Path)
	if err != nil || in.Schema != store.SchemaVersion() {
		t.Errorf("inspect: %+v %v", in, err)
	}
	// The same second again is refused rather than overwritten.
	if _, err := Write(ctx, src, dir, KindJarl, now); err == nil {
		t.Error("overwrote a backup")
	}
	// No temporary files are left.
	ents, _ := os.ReadDir(dir)
	if len(ents) != 1 {
		t.Errorf("files: %v", ents)
	}
	// A missing database is an error, and isn't created.
	missing := filepath.Join(t.TempDir(), "nope.db")
	if _, err := Write(ctx, missing, dir, KindJarl, now.Add(time.Second)); err == nil {
		t.Error("backed up a missing database")
	}
	if _, err := os.Stat(missing); err == nil {
		t.Error("created the missing database")
	}
}

func TestVerifyCorrupt(t *testing.T) {
	ctx := context.Background()
	path := filepath.Join(t.TempDir(), "bad.db")
	os.WriteFile(path, []byte("SQLite format 3\x00 but not really a database, just text that goes on"), 0o600)
	if err := Verify(ctx, path); err == nil {
		t.Error("a corrupt file passed")
	}
	if _, err := Inspect(ctx, path); err == nil {
		t.Error("inspected a corrupt file")
	}
}

func TestPrune(t *testing.T) {
	dir := t.TempDir()
	now := time.Date(2026, 10, 8, 3, 0, 0, 0, time.UTC)
	touch := func(name string) {
		os.WriteFile(filepath.Join(dir, name), []byte("x"), 0o600)
	}
	// Daily backups from 0 to 39 days old, plus files that aren't ours.
	for d := 0; d < 40; d++ {
		touch(Name(KindJarl, now.Add(-time.Duration(d)*24*time.Hour)))
	}
	touch(Name(KindStats, now.Add(-100*24*time.Hour)))
	touch("jarl-before-upgrade.db")
	touch("jarl-20200101T000000Z.db.bak")
	touch("notes.txt")

	removed, err := Prune(dir, KindJarl, now, 30*24*time.Hour, 7)
	if err != nil {
		t.Fatal(err)
	}
	if len(removed) != 9 { // 31..39 days old
		t.Errorf("removed %d: %v", len(removed), removed)
	}
	files, _ := List(dir)
	jarl := 0
	for _, f := range files {
		if f.Kind == KindJarl {
			jarl++
			if now.Sub(f.Time) > 30*24*time.Hour {
				t.Errorf("kept %s", f.Path)
			}
		}
	}
	if jarl != 31 {
		t.Errorf("%d jarl backups left", jarl)
	}
	for _, name := range []string{"jarl-before-upgrade.db", "jarl-20200101T000000Z.db.bak", "notes.txt", Name(KindStats, now.Add(-100*24*time.Hour))} {
		if _, err := os.Stat(filepath.Join(dir, name)); err != nil {
			t.Errorf("%s was deleted", name)
		}
	}

	// After a long outage every backup is old: the newest keepAtLeast stay.
	removed, _ = Prune(dir, KindJarl, now.Add(365*24*time.Hour), 30*24*time.Hour, 7)
	files, _ = List(dir)
	n := 0
	for _, f := range files {
		if f.Kind == KindJarl {
			n++
		}
	}
	if n != 7 || len(removed) != 24 {
		t.Errorf("after a year: %d left, %d removed", n, len(removed))
	}
	// Retention 0 keeps everything.
	if removed, _ := Prune(dir, KindJarl, now.Add(3650*24*time.Hour), 0, 1); len(removed) != 0 {
		t.Errorf("retention 0 removed %v", removed)
	}
}

func TestPruneTempFiles(t *testing.T) {
	dir := t.TempDir()
	now := time.Now()
	old := filepath.Join(dir, "."+Name(KindJarl, now.Add(-48*time.Hour))+".tmp")
	fresh := filepath.Join(dir, "."+Name(KindJarl, now)+".tmp")
	os.WriteFile(old, nil, 0o600)
	os.WriteFile(fresh, nil, 0o600)
	os.Chtimes(old, now.Add(-48*time.Hour), now.Add(-48*time.Hour))
	Prune(dir, KindJarl, now, 24*time.Hour, 1)
	if _, err := os.Stat(old); err == nil {
		t.Error("old temporary file kept")
	}
	if _, err := os.Stat(fresh); err != nil {
		t.Error("a running backup's temporary file was deleted")
	}
}