feat(app): add the entry view model and the OTP period

Totp now carries its period, so the entry view can draw how much of the
code's lifetime is left. EntryFields groups a decrypted entry the way the
spec lays it out.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

2 files changed, 92 insertions, 0 deletions

diff --git a/app/src/main/java/app/passwordstore/ui/entry/EntryModel.kt b/app/src/main/java/app/passwordstore/ui/entry/EntryModel.kt
new file mode 100644
index 00000000..8dbc9eb9
--- /dev/null
+++ b/app/src/main/java/app/passwordstore/ui/entry/EntryModel.kt
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2026 Danilo M. <danix@danix.xyz>
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package app.passwordstore.ui.entry
+
+import androidx.compose.runtime.Immutable
+import app.passwordstore.data.passfile.PasswordEntry
+import app.passwordstore.data.passfile.Totp
+import kotlinx.collections.immutable.ImmutableList
+import kotlinx.collections.immutable.toImmutableList
+
+/**
+ * What the entry view shows. [password] and [username] open the first group (the one-time code
+ * joins them from the entry's TOTP flow); [extras] are the remaining `key: value` lines in file
+ * order, plus lines that are not `key: value` under the parser's "Extra Content" key. Blank values
+ * are null, so their rows are not shown.
+ */
+@Immutable
+data class EntryFields(
+  val password: String?,
+  val username: String?,
+  val extras: ImmutableList<Pair<String, String>>,
+)
+
+fun entryFields(entry: PasswordEntry): EntryFields =
+  EntryFields(
+    password = entry.password?.takeIf { it.isNotBlank() },
+    username = entry.username?.takeIf { it.isNotBlank() },
+    extras = entry.extraContent.toList().toImmutableList(),
+  )
+
+/** Share of the code's lifetime left: 1 right after it was generated, toward 0 at expiry. */
+fun Totp.fractionLeft(): Float = (remainingTime / period).toFloat()
diff --git a/app/src/test/java/app/passwordstore/ui/entry/EntryModelTest.kt b/app/src/test/java/app/passwordstore/ui/entry/EntryModelTest.kt
new file mode 100644
index 00000000..290c51a9
--- /dev/null
+++ b/app/src/test/java/app/passwordstore/ui/entry/EntryModelTest.kt
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2026 Danilo M. <danix@danix.xyz>
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package app.passwordstore.ui.entry
+
+import app.passwordstore.data.passfile.PasswordEntry
+import app.passwordstore.data.passfile.Totp
+import app.passwordstore.util.time.UserClock
+import app.passwordstore.util.totp.UriTotpFinder
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNull
+import kotlin.test.assertTrue
+import kotlin.time.Duration.Companion.seconds
+
+class EntryModelTest {
+
+  private fun entry(content: String) =
+    PasswordEntry(UserClock(), UriTotpFinder(), content.encodeToByteArray())
+
+  @Test
+  fun firstGroupAndExtrasInFileOrder() {
+    val fields =
+      entryFields(entry("hunter2\nusername: alice\nurl: https://example.org\npin: 1234\n"))
+    assertEquals("hunter2", fields.password)
+    assertEquals("alice", fields.username)
+    assertEquals(listOf("url" to "https://example.org", "pin" to "1234"), fields.extras)
+  }
+
+  @Test
+  fun blankPasswordAndMissingUsernameAreLeftOut() {
+    val fields = entryFields(entry("\nnote: none\n"))
+    assertNull(fields.password)
+    assertNull(fields.username)
+    assertEquals(listOf("note" to "none"), fields.extras)
+  }
+
+  @Test
+  fun otpUriIsNotAnExtraField() {
+    val fields =
+      entryFields(
+        entry(
+          "s3cret\notpauth://totp/example.com:carol?secret=JBSWY3DPEHPK3PXP&issuer=example.com\n"
+        )
+      )
+    assertEquals("s3cret", fields.password)
+    assertTrue(fields.extras.isEmpty())
+  }
+
+  @Test
+  fun fractionLeftOfTheOtpPeriod() {
+    assertEquals(1f, Totp("123456", 30.seconds, 30.seconds).fractionLeft())
+    assertEquals(0.5f, Totp("123456", 15.seconds, 30.seconds).fractionLeft())
+  }
+}