Add autocrypt line to the compose menu.

Remove the hardcoded HDR_ATTACH offset calcuation, and add an explicit
enum for the "-- Attachments" line to make loops and padding array
sizes easier.

Add security and recommendataion fields on the line.

Add mutt_autocrypt_ui_recommendation, following the autocrypt spec
guidelines.

4 files changed, 109 insertions, 0 deletions

diff --git a/autocrypt/autocrypt.c b/autocrypt/autocrypt.c
index 228c24a6..dd3ccb82 100644
--- a/autocrypt/autocrypt.c
+++ b/autocrypt/autocrypt.c
@@ -22,6 +22,7 @@
 
 #include "mutt.h"
 #include "mutt_curses.h"
+#include "mutt_crypt.h"
 #include "mime.h"
 #include "mutt_idna.h"
 #include "autocrypt.h"
@@ -437,3 +438,74 @@ cleanup:
 
   return rv;
 }
+
+autocrypt_rec_t mutt_autocrypt_ui_recommendation (HEADER *hdr)
+{
+  autocrypt_rec_t rv = AUTOCRYPT_REC_OFF;
+  AUTOCRYPT_ACCOUNT *account = NULL;
+  AUTOCRYPT_PEER *peer = NULL;
+  ADDRESS *recip, *recips = NULL, *last = NULL;
+  int all_encrypt = 1, has_discourage = 0;
+
+  if (!option (OPTAUTOCRYPT) ||
+      mutt_autocrypt_init (0) ||
+      !hdr ||
+      !hdr->env->from ||
+      hdr->env->from->next)
+    return AUTOCRYPT_REC_OFF;
+
+  if (hdr->security & APPLICATION_SMIME)
+    return AUTOCRYPT_REC_OFF;
+
+  if (mutt_autocrypt_db_account_get (hdr->env->from, &account) <= 0)
+    goto cleanup;
+
+  last = rfc822_append (&recips, hdr->env->to, 0);
+  last = rfc822_append (last ? &last : &recips, hdr->env->cc, 0);
+  rfc822_append (last ? &last : &recips, hdr->env->bcc, 0);
+
+  rv = AUTOCRYPT_REC_NO;
+  if (!recips)
+    goto cleanup;
+
+  for (recip = recips; recip; recip = recip->next)
+  {
+    if (mutt_autocrypt_db_peer_get (recip, &peer) <= 0)
+      goto cleanup;
+
+    if (mutt_autocrypt_gpgme_is_valid_key (peer->keyid))
+    {
+      if (!(peer->last_seen && peer->autocrypt_timestamp) ||
+          (peer->last_seen - peer->autocrypt_timestamp > 35 * 24 * 60 * 60))
+      {
+        has_discourage = 1;
+        all_encrypt = 0;
+      }
+
+      if (!account->prefer_encrypt || !peer->prefer_encrypt)
+        all_encrypt = 0;
+    }
+    else if (mutt_autocrypt_gpgme_is_valid_key (peer->gossip_keyid))
+    {
+      has_discourage = 1;
+      all_encrypt = 0;
+    }
+    else
+      goto cleanup;
+
+    mutt_autocrypt_db_peer_free (&peer);
+  }
+
+  if (all_encrypt)
+    rv = AUTOCRYPT_REC_YES;
+  else if (has_discourage)
+    rv = AUTOCRYPT_REC_DISCOURAGE;
+  else
+    rv = AUTOCRYPT_REC_AVAILABLE;
+
+cleanup:
+  mutt_autocrypt_db_account_free (&account);
+  rfc822_free_address (&recips);
+  mutt_autocrypt_db_peer_free (&peer);
+  return rv;
+}
diff --git a/autocrypt/autocrypt.h b/autocrypt/autocrypt.h
index a2401bc3..2608277d 100644
--- a/autocrypt/autocrypt.h
+++ b/autocrypt/autocrypt.h
@@ -62,9 +62,19 @@ typedef struct
   char *gossip_keydata;
 } AUTOCRYPT_GOSSIP_HISTORY;
 
+typedef enum
+{
+  AUTOCRYPT_REC_OFF,
+  AUTOCRYPT_REC_NO,
+  AUTOCRYPT_REC_DISCOURAGE,
+  AUTOCRYPT_REC_AVAILABLE,
+  AUTOCRYPT_REC_YES
+} autocrypt_rec_t;
+
 int mutt_autocrypt_init (int);
 void mutt_autocrypt_cleanup (void);
 int mutt_autocrypt_process_autocrypt_header (HEADER *hdr, ENVELOPE *env);
 int mutt_autocrypt_process_gossip_header (HEADER *hdr, ENVELOPE *env);
+autocrypt_rec_t mutt_autocrypt_ui_recommendation (HEADER *hdr);
 
 #endif
diff --git a/autocrypt/autocrypt_gpgme.c b/autocrypt/autocrypt_gpgme.c
index 952f648b..84bb9ffc 100644
--- a/autocrypt/autocrypt_gpgme.c
+++ b/autocrypt/autocrypt_gpgme.c
@@ -212,3 +212,29 @@ cleanup:
   mutt_buffer_pool_release (&raw_keydata);
   return rv;
 }
+
+int mutt_autocrypt_gpgme_is_valid_key (const char *keyid)
+{
+  int rv = 0;
+  gpgme_ctx_t ctx = NULL;
+  gpgme_key_t key = NULL;
+
+  if (!keyid)
+    return 0;
+
+  if (create_gpgme_context (&ctx))
+    goto cleanup;
+
+  if (gpgme_get_key (ctx, keyid, &key, 0))
+    goto cleanup;
+
+  rv = 1;
+  if (key->revoked || key->expired || key->disabled || key->invalid ||
+      !key->can_encrypt)
+    rv = 0;
+
+cleanup:
+  gpgme_key_unref (key);
+  gpgme_release (ctx);
+  return rv;
+}
diff --git a/autocrypt/autocrypt_private.h b/autocrypt/autocrypt_private.h
index 1ba51920..3e370da6 100644
--- a/autocrypt/autocrypt_private.h
+++ b/autocrypt/autocrypt_private.h
@@ -54,5 +54,6 @@ int mutt_autocrypt_schema_update (void);
 int mutt_autocrypt_gpgme_init (void);
 int mutt_autocrypt_gpgme_create_key (ADDRESS *addr, BUFFER *keyid, BUFFER *keydata);
 int mutt_autocrypt_gpgme_import_key (const char *keydata, BUFFER *keyid);
+int mutt_autocrypt_gpgme_is_valid_key (const char *keyid);
 
 #endif