/* Drives the download state machine without a network: feeds blocks straight
 * from the original file (as a perfect seed would) and checks the reassembled,
 * hash-verified output on disk is byte-identical. Also checks a corrupt block
 * is rejected at piece completion. */
#include "naut/piece.h"
#include "naut/metainfo.h"
#include "naut/storage.h"
#include "naut/worker.h"
#include "test.h"
#include <poll.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#ifndef NAUT_FIXTURES
#define NAUT_FIXTURES "tests/fixtures"
#endif

static uint8_t *slurp(const char *path, size_t *len) {
    FILE *f = fopen(path, "rb");
    if (!f) { fprintf(stderr, "  open %s failed\n", path); return NULL; }
    fseek(f, 0, SEEK_END); long n = ftell(f); fseek(f, 0, SEEK_SET);
    uint8_t *b = malloc(n);
    if (fread(b, 1, n, f) != (size_t)n) { fclose(f); free(b); return NULL; }
    fclose(f); *len = (size_t)n; return b;
}

int main(void) {
    /* load torrent + its original payload */
    size_t tlen, olen;
    uint8_t *tor = slurp(NAUT_FIXTURES "/single_v1.torrent", &tlen);
    uint8_t *orig = slurp(NAUT_FIXTURES "/data/single.bin", &olen);
    CHECK(tor && orig);
    if (!tor || !orig) return 1;

    naut_metainfo mi;
    CHECK(naut_metainfo_parse(tor, tlen, &mi) == NAUT_OK);
    CHECK_EQ(mi.total_length, (int64_t)olen);

    char tmpl[] = "/tmp/naut_dl_XXXXXX";
    char *root = mkdtemp(tmpl);
    naut_err err;
    naut_storage *st = naut_storage_open(mi.files, mi.num_files, root, &err);
    CHECK(st && err == NAUT_OK);

    naut_download *d = naut_download_create(&mi, st);
    CHECK(d != NULL);

    /* feed every requested block straight from the original */
    uint32_t idx, begin, len;
    int completed = 0;
    while (naut_download_next_request(d, &idx, &begin, &len)) {
        uint64_t global = (uint64_t)idx * (uint64_t)mi.piece_length + begin;
        bool done = false;
        CHECK(naut_download_on_block(d, idx, begin, orig + global, len, &done) == NAUT_OK);
        if (done) completed++;
    }
    CHECK(naut_download_complete(d));
    CHECK_EQ(completed, (int)naut_download_num_pieces(d));
    CHECK_EQ((long long)naut_download_bytes_done(d), (long long)olen);
    naut_download_destroy(d);

    /* on-disk result must be byte-identical to the original */
    naut_storage_sync(st);
    naut_storage_close(st);
    char outpath[512]; snprintf(outpath, sizeof outpath, "%s/%s", root, mi.files[0].path);
    size_t glen; uint8_t *got = slurp(outpath, &glen);
    CHECK(got && glen == olen && memcmp(got, orig, olen) == 0);
    free(got);

    /* The same path with SHA-1 verification offloaded to bounded workers. */
    {
        char t2[] = "/tmp/naut_async_XXXXXX";
        char *r2 = mkdtemp(t2);
        naut_storage *st2 = naut_storage_open(mi.files, mi.num_files, r2, &err);
        naut_download *d2 = naut_download_create(&mi, st2);
        naut_worker_pool *workers = naut_worker_pool_create(2, 64, -1);
        CHECK(st2 && d2 && workers);
        naut_download_set_worker_pool(d2, workers);
        while (naut_download_next_request(d2, &idx, &begin, &len)) {
            uint64_t global =
                (uint64_t)idx * (uint64_t)mi.piece_length + begin;
            bool done = false;
            CHECK(naut_download_on_block(
                d2, idx, begin, orig + global, len, &done) == NAUT_OK);
            CHECK(!done);
        }
        uint32_t async_completed = 0;
        while (!naut_download_complete(d2)) {
            struct pollfd pfd = {
                .fd = naut_worker_eventfd(workers),
                .events = POLLIN,
            };
            CHECK(poll(&pfd, 1, 5000) > 0);
            uint64_t count;
            (void)read(pfd.fd, &count, sizeof count);
            uint32_t batch = 0;
            CHECK(naut_download_poll(d2, &batch) == NAUT_OK);
            async_completed += batch;
        }
        CHECK_EQ(async_completed, (int)mi.num_pieces);
        naut_worker_pool_destroy(workers);
        naut_download_destroy(d2);
        naut_storage_close(st2);
        char cmd[256];
        snprintf(cmd, sizeof cmd, "rm -rf '%s'", r2);
        if (system(cmd)) {}
    }

    /* corrupt-block rejection: a bad first block fails SHA-1 at completion */
    {
        char t2[] = "/tmp/naut_dl2_XXXXXX"; char *r2 = mkdtemp(t2);
        naut_storage *st2 = naut_storage_open(mi.files, mi.num_files, r2, &err);
        naut_download *d2 = naut_download_create(&mi, st2);
        CHECK(naut_download_next_request(d2, &idx, &begin, &len));   /* piece 0, block 0 */
        uint8_t bad[NAUT_BLOCK];
        memcpy(bad, orig, len); bad[0] ^= 0xff;                      /* flip a bit */
        bool done = false;
        CHECK(naut_download_on_block(d2, idx, begin, bad, len, &done) == NAUT_ERR_PROTO);
        CHECK(!done);
        naut_download_destroy(d2);
        naut_storage_close(st2);
        char cmd[256]; snprintf(cmd, sizeof cmd, "rm -rf '%s'", r2); if (system(cmd)) {}
    }

    char cmd[256]; snprintf(cmd, sizeof cmd, "rm -rf '%s'", root); if (system(cmd)) {}
    naut_metainfo_free(&mi);
    free(tor); free(orig);
    TEST_MAIN_END();
}