#include "cache.h"
#include "transport.h"

#include "run-command.h"
#include "commit.h"
#include "diff.h"
#include "revision.h"

struct helper_data
{
        const char *name;
        struct child_process *helper;
        FILE *out;
        unsigned fetch : 1;
};

static struct child_process *get_helper(struct transport *transport)
{
        struct helper_data *data = transport->data;
        struct strbuf buf = STRBUF_INIT;
        struct child_process *helper;

        if (data->helper)
                return data->helper;

        helper = xcalloc(1, sizeof(*helper));
        helper->in = -1;
        helper->out = -1;
        helper->err = 0;
        helper->argv = xcalloc(4, sizeof(*helper->argv));
        strbuf_addf(&buf, "remote-%s", data->name);
        helper->argv[0] = strbuf_detach(&buf, NULL);
        helper->argv[1] = transport->remote->name;
        helper->argv[2] = transport->url;
        helper->git_cmd = 1;
        if (start_command(helper))
                die("Unable to run helper: git %s", helper->argv[0]);
        data->helper = helper;

        write_str_in_full(helper->in, "capabilities\n");

        data->out = xfdopen(helper->out, "r");
        while (1) {
                if (strbuf_getline(&buf, data->out, '\n') == EOF)
                        exit(128); /* child died, message supplied already */

                if (!*buf.buf)
                        break;
                if (!strcmp(buf.buf, "fetch"))
                        data->fetch = 1;
        }
        return data->helper;
}

static int disconnect_helper(struct transport *transport)
{
        struct helper_data *data = transport->data;
        if (data->helper) {
                write_str_in_full(data->helper->in, "\n");
                close(data->helper->in);
                fclose(data->out);
                finish_command(data->helper);
                free((char *)data->helper->argv[0]);
                free(data->helper->argv);
                free(data->helper);
                data->helper = NULL;
        }
        return 0;
}

static int fetch_with_fetch(struct transport *transport,
                            int nr_heads, const struct ref **to_fetch)
{
        struct helper_data *data = transport->data;
        int i;
        struct strbuf buf = STRBUF_INIT;

        for (i = 0; i < nr_heads; i++) {
                const struct ref *posn = to_fetch[i];
                if (posn->status & REF_STATUS_UPTODATE)
                        continue;

                strbuf_addf(&buf, "fetch %s %s\n",
                            sha1_to_hex(posn->old_sha1), posn->name);
        }

        strbuf_addch(&buf, '\n');
        if (write_in_full(data->helper->in, buf.buf, buf.len) != buf.len)
                die_errno("cannot send fetch to %s", data->name);

        while (1) {
                strbuf_reset(&buf);
                if (strbuf_getline(&buf, data->out, '\n') == EOF)
                        exit(128); /* child died, message supplied already */

                if (!prefixcmp(buf.buf, "lock ")) {
                        const char *name = buf.buf + 5;
                        if (transport->pack_lockfile)
                                warning("%s also locked %s", data->name, name);
                        else
                                transport->pack_lockfile = xstrdup(name);
                }
                else if (!buf.len)
                        break;
                else
                        warning("%s unexpectedly said: '%s'", data->name, buf.buf);
        }
        strbuf_release(&buf);
        return 0;
}

static int fetch(struct transport *transport,
                 int nr_heads, const struct ref **to_fetch)
{
        struct helper_data *data = transport->data;
        int i, count;

        count = 0;
        for (i = 0; i < nr_heads; i++)
                if (!(to_fetch[i]->status & REF_STATUS_UPTODATE))
                        count++;

        if (!count)
                return 0;

        if (data->fetch)
                return fetch_with_fetch(transport, nr_heads, to_fetch);

        return -1;
}

static struct ref *get_refs_list(struct transport *transport, int for_push)
{
        struct helper_data *data = transport->data;
        struct child_process *helper;
        struct ref *ret = NULL;
        struct ref **tail = &ret;
        struct ref *posn;
        struct strbuf buf = STRBUF_INIT;

        helper = get_helper(transport);

        write_str_in_full(helper->in, "list\n");

        while (1) {
                char *eov, *eon;
                if (strbuf_getline(&buf, data->out, '\n') == EOF)
                        exit(128); /* child died, message supplied already */

                if (!*buf.buf)
                        break;

                eov = strchr(buf.buf, ' ');
                if (!eov)
                        die("Malformed response in ref list: %s", buf.buf);
                eon = strchr(eov + 1, ' ');
                *eov = '\0';
                if (eon)
                        *eon = '\0';
                *tail = alloc_ref(eov + 1);
                if (buf.buf[0] == '@')
                        (*tail)->symref = xstrdup(buf.buf + 1);
                else if (buf.buf[0] != '?')
                        get_sha1_hex(buf.buf, (*tail)->old_sha1);
                tail = &((*tail)->next);
        }
        strbuf_release(&buf);

        for (posn = ret; posn; posn = posn->next)
                resolve_remote_symref(posn, ret);

        return ret;
}

int transport_helper_init(struct transport *transport, const char *name)
{
        struct helper_data *data = xcalloc(sizeof(*data), 1);
        data->name = name;

        transport->data = data;
        transport->get_refs_list = get_refs_list;
        transport->fetch = fetch;
        transport->disconnect = disconnect_helper;
        return 0;
}