package storage

import (
	"context"
	"path/filepath"
	"strings"
	"testing"

	"github.com/metazla/meta-core/internal/kv"
)

// newTestClient opens a fresh database in the test's temp dir.
func newTestClient(t *testing.T) *Client {
	t.Helper()
	c := NewClient()
	if err := c.Connect(filepath.Join(t.TempDir(), "meta-core.db")); err != nil {
		t.Fatalf("connect: %v", err)
	}
	t.Cleanup(func() { _ = c.Close() })
	return c
}

// allKeys lists every row (test helper; full scan).
func allKeys(t *testing.T, c *Client) []string {
	t.Helper()
	var keys []string
	if err := c.Store().ScanPrefix(context.Background(), "", 1000, func(rows []kv.KV) error {
		for _, r := range rows {
			keys = append(keys, r.K)
		}
		return nil
	}); err != nil {
		t.Fatalf("scan: %v", err)
	}
	return keys
}

// TestClearAllMetadata_PurgesCIDReverseIndex is the regression test for the
// leak: ClearAllMetadata used to delete every record key and the root index,
// but left the cid:<cid> → root reverse-index entries behind. Those stale
// aliases are not cosmetic — ResolveRoot consults them, so a surviving entry
// silently redirects a later write into a deleted root.
func TestClearAllMetadata_PurgesCIDReverseIndex(t *testing.T) {
	c := newTestClient(t)

	// Two records, each with several CID aliases (a midhash plus siblings) —
	// exactly what the watcher produces.
	aliases := map[string][]string{}
	for i, f := range []string{"watch/a.mkv", "watch/b.mkv"} {
		uuid, err := c.Mint(f, int64(100+i), int64(1000+i))
		if err != nil {
			t.Fatalf("mint: %v", err)
		}
		cids := []string{"bafkmid" + uuid, "bafkfull" + uuid}
		for _, cidStr := range cids {
			if err := c.AddAlias(uuid, cidStr); err != nil {
				t.Fatalf("add alias %s: %v", cidStr, err)
			}
		}
		if _, err := c.AddDuplicatePath(uuid, "watch/copy-"+f); err != nil {
			t.Fatalf("add duplicate: %v", err)
		}
		aliases[uuid] = cids
	}

	// An entry already orphaned by a previous (buggy) clear: a reverse-index
	// key whose root no longer exists. The sweep is expected to collect it too.
	if err := c.SetRawValue(CIDIndexPrefix+"bafkorphan", "01OLDDEADROOT"); err != nil {
		t.Fatalf("seed orphan: %v", err)
	}

	for uuid, cids := range aliases {
		for _, cidStr := range cids {
			if got := c.ResolveRoot(cidStr); got != uuid {
				t.Fatalf("pre-clear ResolveRoot(%s) = %q, want %q", cidStr, got, uuid)
			}
		}
	}

	deleted, err := c.ClearAllMetadata()
	if err != nil {
		t.Fatalf("ClearAllMetadata: %v", err)
	}
	if deleted != 2 {
		t.Errorf("deletedCount = %d, want 2 (files, not keys)", deleted)
	}

	// Nothing record-shaped may survive: not the records, not their aliases,
	// duplicates or search rows, not the pre-existing orphan. (The event
	// streams and the schema sentinel are not metadata and stay.)
	for _, k := range allKeys(t, c) {
		for _, ns := range []string{recordNS, CIDIndexPrefix, rootsNS, ftsNS, dupNS} {
			if strings.HasPrefix(k, ns) {
				t.Errorf("key survived the clear: %q", k)
			}
		}
	}
	var ftsRows int
	if err := c.Store().DB().QueryRow(`SELECT count(*) FROM fts`).Scan(&ftsRows); err != nil || ftsRows != 0 {
		t.Errorf("fts rows after clear = %d (err %v), want 0", ftsRows, err)
	}

	for _, cids := range aliases {
		for _, cidStr := range cids {
			if got := c.ResolveRoot(cidStr); got != cidStr {
				t.Errorf("post-clear ResolveRoot(%s) = %q, want the hash unchanged (stale alias)", cidStr, got)
			}
		}
	}
	if got, err := c.GetByCID("bafkorphan"); err != nil || got != "" {
		t.Errorf("post-clear GetByCID(bafkorphan) = %q (err %v), want \"\"", got, err)
	}
}

// TestClearAllMetadata_LeavesForeignKeysAlone guards the sweep's blast radius:
// keys outside the metadata namespaces (magnet cache, coverage markers, a key
// that merely CONTAINS "cid:") must survive a metadata wipe.
func TestClearAllMetadata_LeavesForeignKeysAlone(t *testing.T) {
	c := newTestClient(t)

	uuid, err := c.Mint("watch/a.mkv", 100, 1000)
	if err != nil {
		t.Fatalf("mint: %v", err)
	}
	if err := c.AddAlias(uuid, "bafkmine"); err != nil {
		t.Fatalf("add alias: %v", err)
	}
	for k, v := range map[string]string{"other:cid:bafktheirs": "01THEIRROOT", "btmagnet:abc": "magnet:?xt=urn:btih:abc", "unrelated": "keep-me"} {
		if err := c.SetRawValue(k, v); err != nil {
			t.Fatalf("seed %s: %v", k, err)
		}
	}

	if _, err := c.ClearAllMetadata(); err != nil {
		t.Fatalf("ClearAllMetadata: %v", err)
	}

	for _, k := range []string{"other:cid:bafktheirs", "btmagnet:abc", "unrelated"} {
		if _, _, ok, _ := c.GetKeyInfo(k); !ok {
			t.Errorf("clear deleted foreign key %q", k)
		}
	}
	if _, _, ok, _ := c.GetKeyInfo(CIDIndexPrefix + "bafkmine"); ok {
		t.Errorf("own reverse-index entry survived the clear")
	}
}

// withClient runs fn against a fresh client.
func withClient(t *testing.T, fn func(t *testing.T, c *Client)) {
	t.Helper()
	fn(t, newTestClient(t))
}