package backend

import (
	"strings"
	"testing"

	"github.com/emersion/go-imap/v2"
)

func TestSanitizeIMAPFlagsDropsRecentAndWildcard(t *testing.T) {
	got := sanitizeIMAPFlags([]imap.Flag{imap.FlagSeen, imap.Flag(`\Recent`), imap.FlagWildcard, imap.FlagAnswered})
	if len(got) != 2 || got[0] != imap.FlagSeen || got[1] != imap.FlagAnswered {
		t.Fatalf("sanitizeIMAPFlags returned %#v", got)
	}
}

func TestMessageIDFallsBackToBodyHash(t *testing.T) {
	body := []byte("From: a@example.com\r\nSubject: Test\r\n\r\nBody")
	id := messageID(body)
	if !strings.HasPrefix(id, "sha256:") {
		t.Fatalf("expected sha256 fallback, got %q", id)
	}
	if id != messageID(body) {
		t.Fatal("messageID hash fallback is not stable")
	}
}

func TestNormalizeMessageIDExtractsBracketedIDBeforeBrokenComment(t *testing.T) {
	tests := map[string]string{
		"<normal@example.com>":    "normal@example.com",
		"bracketless@example.com": "bracketless@example.com",
		" <5486CB7400AF1FB7@mr001msb.fastweb.it> (added by postmaster) ": "5486CB7400AF1FB7@mr001msb.fastweb.it",
		"comment <embedded@example.com> trailing":                        "embedded@example.com",
	}
	for input, want := range tests {
		if got := normalizeMessageID(input); got != want {
			t.Errorf("normalizeMessageID(%q)=%q, want %q", input, got, want)
		}
	}
}

func TestIdentityKeepsOldMalformedHeaderNormalizationAsAlias(t *testing.T) {
	tests := []struct {
		header string
		clean  string
		legacy string
	}{
		{
			header: `<476BDFDB019289BE@mail21.bluewin.ch> (added by postmaster@bluewin.ch)`,
			clean:  `476BDFDB019289BE@mail21.bluewin.ch`,
			legacy: `476BDFDB019289BE@mail21.bluewin.ch> (added by postmaster@bluewin.ch)`,
		},
		{
			header: `<22578196653698419217.BB8A0E8F48F3F290@dr-gold.de>+D271B1409C3C6028`,
			clean:  `22578196653698419217.BB8A0E8F48F3F290@dr-gold.de`,
			legacy: `22578196653698419217.BB8A0E8F48F3F290@dr-gold.de>+D271B1409C3C6028`,
		},
	}
	for _, tt := range tests {
		body := []byte("Message-ID: " + tt.header + "\r\nSubject: malformed ID\r\n\r\nbody")
		identity := identityForRawMessage(RawMessage{MessageID: messageID(body), Body: body})
		if identity.MessageID != tt.clean {
			t.Fatalf("MessageID=%q, want %q", identity.MessageID, tt.clean)
		}
		found := false
		for _, alias := range identity.LegacyMessageIDs {
			if alias == tt.legacy {
				found = true
				break
			}
		}
		if !found {
			t.Fatalf("legacy alias %q missing from %#v", tt.legacy, identity.LegacyMessageIDs)
		}
	}
}

func TestBodySHA256IsStableAcrossMboxNormalization(t *testing.T) {
	raw := []byte("From: a@example.com\r\nSubject: Test\r\n\r\nFirst\r\nFrom escaped\r\n\r\n")
	record := mboxRecord(RawMessage{Body: raw})
	parts := splitMboxRecordsWithOffsets(record)
	if len(parts) != 1 {
		t.Fatalf("mbox parts=%d, want 1", len(parts))
	}
	if got, want := bodySHA256(parts[0].Message), bodySHA256(raw); got != want {
		t.Fatalf("mbox hash=%s, raw hash=%s", got, want)
	}
}

func TestIdentityUsesMessageIDAndBodyHash(t *testing.T) {
	first := identityForRawMessage(RawMessage{MessageID: "<same@example.com>", Body: []byte("Message-ID: <same@example.com>\r\n\r\nfirst")})
	second := identityForRawMessage(RawMessage{MessageID: "<same@example.com>", Body: []byte("Message-ID: <same@example.com>\r\n\r\nsecond")})
	if first.MessageID != second.MessageID {
		t.Fatalf("message IDs differ: %#v %#v", first, second)
	}
	if first.BodySHA256 == second.BodySHA256 {
		t.Fatalf("different bodies have same identity hash: %#v %#v", first, second)
	}
}

func TestIdentityWithoutMessageIDKeepsLegacyRawHash(t *testing.T) {
	body := []byte("From: a@example.com\r\n\r\nbody")
	identity := identityForRawMessage(RawMessage{MessageID: messageID(body), Body: body})
	if identity.MessageID != "" || identity.BodySHA256 == "" || !strings.HasPrefix(identity.LegacyMessageID, "sha256:") {
		t.Fatalf("unexpected identity: %#v", identity)
	}
}