package io.flamenet.e2e

import org.json.JSONObject
import javax.crypto.KeyGenerator
import kotlin.test.Test
import kotlin.test.assertEquals
import kotlin.test.assertTrue

/**
 * Disappearing messages (§6.11), at the vault.
 */
class DisappearingTest {
    private class MapStorage : Vault.Storage {
        private val records = mutableMapOf<String, ByteArray>()

        override fun read(name: String) = records[name]

        override fun write(
            name: String,
            bytes: ByteArray,
        ) {
            records[name] = bytes
        }

        override fun delete(name: String) {
            records.remove(name)
        }

        override fun names() = records.keys.toList()
    }

    private fun vault() = Vault(MapStorage(), KeyGenerator.getInstance("AES").apply { init(256) }.generateKey())

    private fun line(
        text: String,
        at: Long,
    ) = JSONObject().put("text", text).put("mine", true).put("at", at)

    private val now = 1_700_000_000_000L

    @Test
    fun `with no timer nothing is removed`() {
        val v = vault()
        v.append("t", line("ancient", 1L))
        assertEquals(1, v.history("t", now).length())
    }

    @Test
    fun `messages older than the timer are gone on the next read`() {
        val v = vault()
        v.saveDisappearSeconds("t", 60)
        v.append("t", line("old", now - 120_000))
        v.append("t", line("fresh", now - 10_000))

        val kept = v.history("t", now)
        assertEquals(1, kept.length())
        assertEquals("fresh", kept.getJSONObject(0).optString("text"))
    }

    /** Gone from disk, not merely filtered out of the answer. */
    @Test
    fun `expiry is a deletion, not a filter`() {
        val v = vault()
        v.saveDisappearSeconds("t", 60)
        v.append("t", line("old", now - 120_000))
        v.history("t", now)

        // Read again with the timer switched off: an expired message must not
        // come back, which it would if the first read had only hidden it.
        v.saveDisappearSeconds("t", 0)
        assertEquals(0, v.history("t", now).length())
    }

    /**
     * A message with no timestamp predates the field.
     */
    @Test
    fun `a message with no timestamp is kept`() {
        val v = vault()
        v.saveDisappearSeconds("t", 60)
        v.append("t", JSONObject().put("text", "from before").put("mine", true))
        assertEquals(1, v.history("t", now).length())
    }

    @Test
    fun `the timer is per conversation`() {
        val v = vault()
        v.saveDisappearSeconds("timed", 60)
        v.append("timed", line("old", now - 120_000))
        v.append("untimed", line("old", now - 120_000))

        assertEquals(0, v.history("timed", now).length())
        assertEquals(1, v.history("untimed", now).length())
    }

    @Test
    fun `turning the timer off forgets it`() {
        val v = vault()
        v.saveDisappearSeconds("t", 3600)
        assertEquals(3600, v.disappearSeconds("t"))
        v.saveDisappearSeconds("t", 0)
        assertEquals(0, v.disappearSeconds("t"))
    }

    /** Exactly at the boundary the message survives, off-by-one deletes data. */
    @Test
    fun `a message exactly at the cutoff survives`() {
        val v = vault()
        v.saveDisappearSeconds("t", 60)
        v.append("t", line("edge", now - 60_000))
        assertTrue(v.history("t", now).length() == 1)
    }
}