/*
 * peer_compat.c - Legacy single-peer peer_* ABI implemented as a thin wrapper
 * over the multi-peer engine. A peer_handle is a private engine configured with
 * exactly one loop, holding one torrent with one connection. The semantics match
 * the old standalone peer, so existing callers and tests keep working unchanged.
 */
#include "../include/peer.h"
#include "../include/engine.h"

#include <stdlib.h>
#include <string.h>

struct peer_handle {
    engine  *eng;
    uint32_t tid;
    uint32_t num_pieces;
};

peer_handle *peer_create(const peer_config *cfg) {
    if (!cfg || cfg->num_pieces == 0 || cfg->piece_length == 0 ||
        cfg->total_size == 0)
        return NULL;

    peer_handle *h = calloc(1, sizeof *h);
    if (!h) return NULL;

    engine_config ec;
    memset(&ec, 0, sizeof ec);
    ec.loop_count = 1;                       /* single loop = single peer    */
    ec.slots_per_loop = cfg->num_slots;      /* 0 => engine default          */
    ec.max_pipeline = cfg->max_pipeline;
    ec.request_timeout_ms = cfg->request_timeout_ms;
    ec.recv_buffer_bytes = cfg->recv_buffer_bytes;

    h->eng = engine_create(&ec);
    if (!h->eng) { free(h); return NULL; }

    int32_t id = engine_add_torrent(h->eng, cfg->info_hash, cfg->peer_id,
                                    cfg->piece_length, cfg->total_size,
                                    cfg->num_pieces);
    if (id < 0) { engine_destroy(h->eng); free(h); return NULL; }
    h->tid = (uint32_t)id;
    h->num_pieces = cfg->num_pieces;
    return h;
}

int peer_start(peer_handle *h, const char *ip, uint16_t port) {
    if (!h || !ip) return -1;
    return engine_add_peer(h->eng, h->tid, ip, port);
}

int peer_set_priorities(peer_handle *h, const uint8_t *priorities, uint32_t count) {
    if (!h) return -1;
    return engine_set_priorities(h->eng, h->tid, priorities, count);
}

int peer_set_priority(peer_handle *h, uint32_t piece_index, uint8_t priority) {
    if (!h) return -1;
    return engine_set_priority(h->eng, h->tid, piece_index, priority);
}

int peer_request_piece(peer_handle *h, uint32_t piece_index) {
    if (!h) return -1;
    return engine_request_piece(h->eng, h->tid, piece_index);
}

void peer_stop(peer_handle *h) {
    /* The engine has no per-torrent stop; teardown happens in peer_destroy.
     * Connections idle harmlessly until then. */
    (void)h;
}

void peer_destroy(peer_handle *h) {
    if (!h) return;
    if (h->eng) engine_destroy(h->eng);
    free(h);
}

void *peer_arena_base(const peer_handle *h) {
    return engine_arena_base(h->eng, 0);
}

uint64_t peer_arena_bytes(const peer_handle *h) {
    return engine_arena_bytes(h->eng, 0);
}

uint32_t peer_poll_ready(peer_handle *h, block_desc *out, uint32_t max) {
    uint32_t total = 0;
    engine_block tmp[256];
    while (total < max) {
        uint32_t want = max - total;
        if (want > 256) want = 256;
        uint32_t n = engine_poll_ready(h->eng, tmp, want);
        for (uint32_t i = 0; i < n; i++) {
            out[total].piece = tmp[i].piece;
            out[total].begin = tmp[i].begin;
            out[total].len   = tmp[i].len;
            out[total].slot  = tmp[i].slot;   /* single loop => loop index 0  */
            total++;
        }
        if (n < want) break;
    }
    return total;
}

void peer_release_slot(peer_handle *h, uint32_t slot) {
    engine_release_slot(h->eng, 0, slot);
}

int peer_wait(peer_handle *h, int timeout_ms) {
    return engine_wait(h->eng, timeout_ms);
}

void peer_get_status(const peer_handle *h, peer_status *out) {
    torrent_status ts;
    engine_torrent_status(h->eng, h->tid, &ts);
    out->state = ts.state;
    out->error = ts.error;
    out->bytes_received = ts.bytes_received;
    out->blocks_received = ts.blocks_received;
    out->outstanding = ts.outstanding;
    out->free_slots = ts.free_slots;
    out->pipeline_target = ts.pipeline_target;
    out->rate_bps = ts.rate_bps;
    out->rtt_min_ms = ts.rtt_min_ms;
}