/* P0-15e: Cap'n Proto partial merge semantics
 *
 * Verifies that the three persistence Cap'n Proto mapped types
 * (capnp_persist_cfg_t, capnp_snap_hdr_t, capnp_repl_envelope_t)
 * and the generated struct PersistConfig / SnapshotHeader / ReplEnvelope
 * round-trip through their C struct representations correctly.
 *
 * These are structural/compile-time + value round-trip tests that span
 * the Cap'n Proto schema generation (P0-C) and the typemap.h definitions.
 */
#include <stdint.h>
#include <stdio.h>
#include <string.h>

#include <unity/unity.h>

#include "config.h"
#include "controller.capnp.h"
#include "persist.h"

/* ------------------------------------------------------------------ */
/* Helpers: persist_config_t → capnp_persist_cfg_t round-trip         */
/* ------------------------------------------------------------------ */

/* Manually map persist_config_t fields to capnp_persist_cfg_t, matching the
 * field mapping in the persist.c checkpoint serialisation path. */
static capnp_persist_cfg_t cfg_to_capnp(const persist_config_t* c)
{
    capnp_persist_cfg_t out;
    memset(&out, 0, sizeof(out));
    out.walSyncMs             = c->wal_sync_ms;
    out.snapIntervalS         = c->snap_interval_s;
    out.snapWalSizeMb         = c->snap_wal_size_mb;
    out.snapKeepN             = c->snap_keep_n;
    out.transientJobTimeoutS  = c->transient_job_timeout_s;
    out.finishedRetainS       = c->finished_retain_s;
    out.workerRetainS         = c->worker_retain_s;
    out.syncTimeoutMs         = c->sync_timeout_ms;
    return out;
}

/* ------------------------------------------------------------------ */
/* Test 1: persist_config_t → capnp_persist_cfg_t round-trip          */
/* ------------------------------------------------------------------ */

static void test_persist_config_capnp_round_trip(void)
{
    persist_config_t src = persist_config_defaults();
    /* Override to known values for deterministic checking */
    src.wal_sync_ms             = 42u;
    src.snap_interval_s         = 120u;
    src.snap_wal_size_mb        = 128u;
    src.snap_keep_n             = 3u;
    src.transient_job_timeout_s = 600u;
    src.finished_retain_s       = 7200u;
    src.worker_retain_s         = 172800u;
    src.sync_timeout_ms         = 100u;

    capnp_persist_cfg_t out = cfg_to_capnp(&src);

    TEST_ASSERT_EQUAL_UINT32(src.wal_sync_ms,             out.walSyncMs);
    TEST_ASSERT_EQUAL_UINT32(src.snap_interval_s,         out.snapIntervalS);
    TEST_ASSERT_EQUAL_UINT32(src.snap_wal_size_mb,        out.snapWalSizeMb);
    TEST_ASSERT_EQUAL_UINT32(src.snap_keep_n,             out.snapKeepN);
    TEST_ASSERT_EQUAL_UINT32(src.transient_job_timeout_s, out.transientJobTimeoutS);
    TEST_ASSERT_EQUAL_UINT32(src.finished_retain_s,       out.finishedRetainS);
    TEST_ASSERT_EQUAL_UINT32(src.worker_retain_s,         out.workerRetainS);
    TEST_ASSERT_EQUAL_UINT32(src.sync_timeout_ms,         out.syncTimeoutMs);

    printf("test_persist_config_capnp_round_trip: PASS\n");
}

/* ------------------------------------------------------------------ */
/* Test 2: SnapshotHeader struct fields and version default            */
/* ------------------------------------------------------------------ */

static void test_snapshot_header_capnp_fields(void)
{
    /* Verify struct size constant matches the documented schema */
    TEST_ASSERT_EQUAL_INT(48, (int)SnapshotHeader_struct_bytes_count);

    /* Populate a capnp_snap_hdr_t with known values and check them */
    capnp_snap_hdr_t hdr;
    memset(&hdr, 0, sizeof(hdr));
    hdr.lsn            = 12345ULL;
    hdr.term           = 2ULL;
    hdr.timestamp      = 999999ULL;
    hdr.version        = 1u;
    hdr.nJobs          = 10u;
    hdr.nQueues        = 3u;
    hdr.nWorkers       = 5u;
    hdr.checksum       = 0xDEADBEEFu;
    hdr.headerChecksum = 0xCAFEBABEu;

    TEST_ASSERT_EQUAL_UINT64(12345ULL, hdr.lsn);
    TEST_ASSERT_EQUAL_UINT64(2ULL,     hdr.term);
    TEST_ASSERT_EQUAL_UINT64(999999ULL, hdr.timestamp);
    TEST_ASSERT_EQUAL_UINT32(1u,        hdr.version);
    TEST_ASSERT_EQUAL_UINT32(10u,       hdr.nJobs);
    TEST_ASSERT_EQUAL_UINT32(3u,        hdr.nQueues);
    TEST_ASSERT_EQUAL_UINT32(5u,        hdr.nWorkers);
    TEST_ASSERT_EQUAL_UINT32(0xDEADBEEFu, hdr.checksum);
    TEST_ASSERT_EQUAL_UINT32(0xCAFEBABEu, hdr.headerChecksum);

    printf("test_snapshot_header_capnp_fields: PASS\n");
}

/* ------------------------------------------------------------------ */
/* Test 3: ReplEnvelope struct fields accessible                       */
/* ------------------------------------------------------------------ */

static void test_repl_envelope_capnp_fields(void)
{
    /* Verify struct size constant */
    TEST_ASSERT_EQUAL_INT(40, (int)ReplEnvelope_struct_bytes_count);

    capnp_repl_envelope_t env;
    memset(&env, 0, sizeof(env));
    env.term      = 7ULL;
    env.lsn       = 100ULL;
    env.entryType = (uint32_t)WAL_JOB_SUBMIT;
    env.payload   = NULL; /* optional data pointer */
    env.crc       = 0x12345678u;
    env.prevCrc   = WAL_CRC_NONE;

    TEST_ASSERT_EQUAL_UINT64(7ULL,               env.term);
    TEST_ASSERT_EQUAL_UINT64(100ULL,             env.lsn);
    TEST_ASSERT_EQUAL_UINT32(WAL_JOB_SUBMIT,     env.entryType);
    TEST_ASSERT_EQUAL_UINT32(0x12345678u,        env.crc);
    TEST_ASSERT_EQUAL_UINT32(WAL_CRC_NONE,       env.prevCrc);

    printf("test_repl_envelope_capnp_fields: PASS\n");
}

/* ------------------------------------------------------------------ */
/* Suite entry point                                                    */
/* ------------------------------------------------------------------ */

void test_e2e_capnp(void)
{
    printf("\n>> P0-15e: Cap'n Proto partial merge semantics\n\n");

    RUN_TEST(test_persist_config_capnp_round_trip);
    RUN_TEST(test_snapshot_header_capnp_fields);
    RUN_TEST(test_repl_envelope_capnp_fields);
}