/* Proves the "move files as they finish" feature at the engine level:
 *  - per-file completion fires the moment a file's last piece verifies,
 *    BEFORE the whole torrent is done;
 *  - a completed file can be relocated mid-download while later pieces (for
 *    other files) keep arriving, with no corruption. */
#include "naut/piece.h"
#include "naut/metainfo.h"
#include "naut/storage.h"
#include "test.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.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) 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;
}

struct cbctx {
    naut_download *d;
    naut_storage  *st;
    char           destdir[256];
    int   order[8], norder;
    bool  moved0;
    bool  file0_done_while_incomplete;
};

static void on_file(void *ctx, uint32_t fidx, const char *path) {
    struct cbctx *c = ctx;
    c->order[c->norder++] = (int)fidx;
    if (fidx == 0 && !c->moved0) {
        c->file0_done_while_incomplete = !naut_download_complete(c->d);
        char dest[512]; snprintf(dest, sizeof dest, "%s/done_a.txt", c->destdir);
        /* relocate file 0 RIGHT NOW, mid-download */
        CHECK(naut_storage_relocate(c->st, 0, dest) == NAUT_OK);
        c->moved0 = true;
        (void)path;
    }
}

int main(void) {
    size_t tlen;
    uint8_t *tor = slurp(NAUT_FIXTURES "/multi_v1.torrent", &tlen);
    CHECK(tor != NULL); if (!tor) return 1;
    naut_metainfo mi;
    CHECK(naut_metainfo_parse(tor, tlen, &mi) == NAUT_OK);
    CHECK_EQ(mi.num_files, 2);

    /* build the flat byte space from the original files, in torrent order */
    uint8_t *global = malloc(mi.total_length);
    uint64_t goff = 0;
    for (size_t i = 0; i < mi.num_files; i++) {
        char p[512]; snprintf(p, sizeof p, "%s/data/%s", NAUT_FIXTURES, mi.files[i].path);
        size_t fl; uint8_t *fb = slurp(p, &fl);
        CHECK(fb && fl == (size_t)mi.files[i].length);
        memcpy(global + goff, fb, fl); goff += fl; free(fb);
    }

    char tmpl[] = "/tmp/naut_fm_XXXXXX"; char *root = mkdtemp(tmpl);
    char destdir[256]; snprintf(destdir, sizeof destdir, "%s_moved", root);

    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);

    struct cbctx ctx; memset(&ctx, 0, sizeof ctx);
    ctx.d = d; ctx.st = st; snprintf(ctx.destdir, sizeof ctx.destdir, "%s", destdir);
    naut_download_set_file_cb(d, on_file, &ctx);

    uint32_t idx, begin, len;
    while (naut_download_next_request(d, &idx, &begin, &len)) {
        uint64_t g = (uint64_t)idx * (uint64_t)mi.piece_length + begin;
        bool done = false;
        CHECK(naut_download_on_block(d, idx, begin, global + g, len, &done) == NAUT_OK);
    }
    CHECK(naut_download_complete(d));

    /* file 0 finished and was moved while the torrent was still incomplete */
    CHECK_EQ(ctx.norder, 2);
    CHECK_EQ(ctx.order[0], 0);             /* file 0 completed first */
    CHECK_EQ(ctx.order[1], 1);
    CHECK(ctx.file0_done_while_incomplete); /* fired before whole-torrent done */
    CHECK(ctx.moved0);
    CHECK(naut_download_file_complete(d, 0) && naut_download_file_complete(d, 1));

    naut_storage_sync(st);
    naut_storage_close(st);

    /* relocated file 0 is at the destination, byte-correct */
    char dest[512]; snprintf(dest, sizeof dest, "%s/done_a.txt", destdir);
    size_t dl; uint8_t *got0 = slurp(dest, &dl);
    CHECK(got0 && dl == (size_t)mi.files[0].length && memcmp(got0, global, dl) == 0);
    free(got0);

    /* file 1 stayed put and is byte-correct (pieces after the move landed fine) */
    char p1[512]; snprintf(p1, sizeof p1, "%s/%s", root, mi.files[1].path);
    size_t l1; uint8_t *got1 = slurp(p1, &l1);
    CHECK(got1 && l1 == (size_t)mi.files[1].length &&
          memcmp(got1, global + mi.files[0].length, l1) == 0);
    free(got1);

    naut_download_destroy(d);
    free(global); free(tor); naut_metainfo_free(&mi);
    char cmd[600]; snprintf(cmd, sizeof cmd, "rm -rf '%s' '%s'", root, destdir);
    if (system(cmd)) {}
    TEST_MAIN_END();
}