#include "cache.h"
#include "transport.h"
#include "quote.h"
#include "run-command.h"
#include "commit.h"
#include "diff.h"
#include "revision.h"
#include "quote.h"
#include "remote.h"

static int debug;

struct helper_data
{
        const char *name;
        struct child_process *helper;
        FILE *out;
        unsigned fetch : 1,
                import : 1,
                option : 1,
                push : 1;
        /* These go from remote name (as in "list") to private name */
        struct refspec *refspecs;
        int refspec_nr;
};

static void sendline(struct helper_data *helper, struct strbuf *buffer)
{
        if (debug)
                fprintf(stderr, "Debug: Remote helper: -> %s", buffer->buf);
        if (write_in_full(helper->helper->in, buffer->buf, buffer->len)
                != buffer->len)
                die_errno("Full write to remote helper failed");
}

static int recvline(struct helper_data *helper, struct strbuf *buffer)
{
        strbuf_reset(buffer);
        if (debug)
                fprintf(stderr, "Debug: Remote helper: Waiting...\n");
        if (strbuf_getline(buffer, helper->out, '\n') == EOF) {
                if (debug)
                        fprintf(stderr, "Debug: Remote helper quit.\n");
                exit(128);
        }

        if (debug)
                fprintf(stderr, "Debug: Remote helper: <- %s\n", buffer->buf);
        return 0;
}

static void xchgline(struct helper_data *helper, struct strbuf *buffer)
{
        sendline(helper, buffer);
        recvline(helper, buffer);
}

static void write_constant(int fd, const char *str)
{
        if (debug)
                fprintf(stderr, "Debug: Remote helper: -> %s", str);
        if (write_in_full(fd, str, strlen(str)) != strlen(str))
                die_errno("Full write to remote helper failed");
}

static struct child_process *get_helper(struct transport *transport)
{
        struct helper_data *data = transport->data;
        struct strbuf buf = STRBUF_INIT;
        struct child_process *helper;
        const char **refspecs = NULL;
        int refspec_nr = 0;
        int refspec_alloc = 0;

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

        data->out = xfdopen(helper->out, "r");
        while (1) {
                recvline(data, &buf);

                if (!*buf.buf)
                        break;
                if (debug)
                        fprintf(stderr, "Debug: Got cap %s\n", buf.buf);
                if (!strcmp(buf.buf, "fetch"))
                        data->fetch = 1;
                if (!strcmp(buf.buf, "option"))
                        data->option = 1;
                if (!strcmp(buf.buf, "push"))
                        data->push = 1;
                if (!strcmp(buf.buf, "import"))
                        data->import = 1;
                if (!data->refspecs && !prefixcmp(buf.buf, "refspec ")) {
                        ALLOC_GROW(refspecs,
                                   refspec_nr + 1,
                                   refspec_alloc);
                        refspecs[refspec_nr++] = strdup(buf.buf + strlen("refspec "));
                }
        }
        if (refspecs) {
                int i;
                data->refspec_nr = refspec_nr;
                data->refspecs = parse_fetch_refspec(refspec_nr, refspecs);
                for (i = 0; i < refspec_nr; i++) {
                        free((char *)refspecs[i]);
                }
                free(refspecs);
        }
        strbuf_release(&buf);
        if (debug)
                fprintf(stderr, "Debug: Capabilities complete.\n");
        return data->helper;
}

static int disconnect_helper(struct transport *transport)
{
        struct helper_data *data = transport->data;
        struct strbuf buf = STRBUF_INIT;

        if (data->helper) {
                if (debug)
                        fprintf(stderr, "Debug: Disconnecting.\n");
                strbuf_addf(&buf, "\n");
                sendline(data, &buf);
                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 const char *unsupported_options[] = {
        TRANS_OPT_UPLOADPACK,
        TRANS_OPT_RECEIVEPACK,
        TRANS_OPT_THIN,
        TRANS_OPT_KEEP
        };
static const char *boolean_options[] = {
        TRANS_OPT_THIN,
        TRANS_OPT_KEEP,
        TRANS_OPT_FOLLOWTAGS
        };

static int set_helper_option(struct transport *transport,
                          const char *name, const char *value)
{
        struct helper_data *data = transport->data;
        struct strbuf buf = STRBUF_INIT;
        int i, ret, is_bool = 0;

        get_helper(transport);

        if (!data->option)
                return 1;

        for (i = 0; i < ARRAY_SIZE(unsupported_options); i++) {
                if (!strcmp(name, unsupported_options[i]))
                        return 1;
        }

        for (i = 0; i < ARRAY_SIZE(boolean_options); i++) {
                if (!strcmp(name, boolean_options[i])) {
                        is_bool = 1;
                        break;
                }
        }

        strbuf_addf(&buf, "option %s ", name);
        if (is_bool)
                strbuf_addstr(&buf, value ? "true" : "false");
        else
                quote_c_style(value, &buf, NULL, 0);
        strbuf_addch(&buf, '\n');

        xchgline(data, &buf);

        if (!strcmp(buf.buf, "ok"))
                ret = 0;
        else if (!prefixcmp(buf.buf, "error")) {
                ret = -1;
        } else if (!strcmp(buf.buf, "unsupported"))
                ret = 1;
        else {
                warning("%s unexpectedly said: '%s'", data->name, buf.buf);
                ret = 1;
        }
        strbuf_release(&buf);
        return ret;
}

static void standard_options(struct transport *t)
{
        char buf[16];
        int n;
        int v = t->verbose;
        int no_progress = v < 0 || (!t->progress && !isatty(1));

        set_helper_option(t, "progress", !no_progress ? "true" : "false");

        n = snprintf(buf, sizeof(buf), "%d", v + 1);
        if (n >= sizeof(buf))
                die("impossibly large verbosity value");
        set_helper_option(t, "verbosity", buf);
}

static int release_helper(struct transport *transport)
{
        struct helper_data *data = transport->data;
        free_refspec(data->refspec_nr, data->refspecs);
        data->refspecs = NULL;
        disconnect_helper(transport);
        free(transport->data);
        return 0;
}

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

        standard_options(transport);

        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');
        sendline(data, &buf);

        while (1) {
                recvline(data, &buf);

                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 get_importer(struct transport *transport, struct child_process *fastimport)
{
        struct child_process *helper = get_helper(transport);
        memset(fastimport, 0, sizeof(*fastimport));
        fastimport->in = helper->out;
        fastimport->argv = xcalloc(5, sizeof(*fastimport->argv));
        fastimport->argv[0] = "fast-import";
        fastimport->argv[1] = "--quiet";

        fastimport->git_cmd = 1;
        return start_command(fastimport);
}

static int fetch_with_import(struct transport *transport,
                             int nr_heads, struct ref **to_fetch)
{
        struct child_process fastimport;
        struct helper_data *data = transport->data;
        int i;
        struct ref *posn;
        struct strbuf buf = STRBUF_INIT;

        get_helper(transport);

        if (get_importer(transport, &fastimport))
                die("Couldn't run fast-import");

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

                strbuf_addf(&buf, "import %s\n", posn->name);
                sendline(data, &buf);
                strbuf_reset(&buf);
        }
        disconnect_helper(transport);
        finish_command(&fastimport);
        free(fastimport.argv);
        fastimport.argv = NULL;

        for (i = 0; i < nr_heads; i++) {
                char *private;
                posn = to_fetch[i];
                if (posn->status & REF_STATUS_UPTODATE)
                        continue;
                if (data->refspecs)
                        private = apply_refspecs(data->refspecs, data->refspec_nr, posn->name);
                else
                        private = strdup(posn->name);
                read_ref(private, posn->old_sha1);
                free(private);
        }
        strbuf_release(&buf);
        return 0;
}

static int fetch(struct transport *transport,
                 int nr_heads, 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);

        if (data->import)
                return fetch_with_import(transport, nr_heads, to_fetch);

        return -1;
}

static int push_refs(struct transport *transport,
                struct ref *remote_refs, int flags)
{
        int force_all = flags & TRANSPORT_PUSH_FORCE;
        int mirror = flags & TRANSPORT_PUSH_MIRROR;
        struct helper_data *data = transport->data;
        struct strbuf buf = STRBUF_INIT;
        struct child_process *helper;
        struct ref *ref;

        if (!remote_refs)
                return 0;

        helper = get_helper(transport);
        if (!data->push)
                return 1;

        for (ref = remote_refs; ref; ref = ref->next) {
                if (ref->peer_ref)
                        hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
                else if (!mirror)
                        continue;

                ref->deletion = is_null_sha1(ref->new_sha1);
                if (!ref->deletion &&
                        !hashcmp(ref->old_sha1, ref->new_sha1)) {
                        ref->status = REF_STATUS_UPTODATE;
                        continue;
                }

                if (force_all)
                        ref->force = 1;

                strbuf_addstr(&buf, "push ");
                if (!ref->deletion) {
                        if (ref->force)
                                strbuf_addch(&buf, '+');
                        if (ref->peer_ref)
                                strbuf_addstr(&buf, ref->peer_ref->name);
                        else
                                strbuf_addstr(&buf, sha1_to_hex(ref->new_sha1));
                }
                strbuf_addch(&buf, ':');
                strbuf_addstr(&buf, ref->name);
                strbuf_addch(&buf, '\n');
        }
        if (buf.len == 0)
                return 0;

        transport->verbose = flags & TRANSPORT_PUSH_VERBOSE ? 1 : 0;
        standard_options(transport);

        if (flags & TRANSPORT_PUSH_DRY_RUN) {
                if (set_helper_option(transport, "dry-run", "true") != 0)
                        die("helper %s does not support dry-run", data->name);
        }

        strbuf_addch(&buf, '\n');
        sendline(data, &buf);

        ref = remote_refs;
        while (1) {
                char *refname, *msg;
                int status;

                recvline(data, &buf);
                if (!buf.len)
                        break;

                if (!prefixcmp(buf.buf, "ok ")) {
                        status = REF_STATUS_OK;
                        refname = buf.buf + 3;
                } else if (!prefixcmp(buf.buf, "error ")) {
                        status = REF_STATUS_REMOTE_REJECT;
                        refname = buf.buf + 6;
                } else
                        die("expected ok/error, helper said '%s'\n", buf.buf);

                msg = strchr(refname, ' ');
                if (msg) {
                        struct strbuf msg_buf = STRBUF_INIT;
                        const char *end;

                        *msg++ = '\0';
                        if (!unquote_c_style(&msg_buf, msg, &end))
                                msg = strbuf_detach(&msg_buf, NULL);
                        else
                                msg = xstrdup(msg);
                        strbuf_release(&msg_buf);

                        if (!strcmp(msg, "no match")) {
                                status = REF_STATUS_NONE;
                                free(msg);
                                msg = NULL;
                        }
                        else if (!strcmp(msg, "up to date")) {
                                status = REF_STATUS_UPTODATE;
                                free(msg);
                                msg = NULL;
                        }
                        else if (!strcmp(msg, "non-fast forward")) {
                                status = REF_STATUS_REJECT_NONFASTFORWARD;
                                free(msg);
                                msg = NULL;
                        }
                }

                if (ref)
                        ref = find_ref_by_name(ref, refname);
                if (!ref)
                        ref = find_ref_by_name(remote_refs, refname);
                if (!ref) {
                        warning("helper reported unexpected status of %s", refname);
                        continue;
                }

                ref->status = status;
                ref->remote_status = msg;
        }
        strbuf_release(&buf);
        return 0;
}

static int has_attribute(const char *attrs, const char *attr) {
        int len;
        if (!attrs)
                return 0;

        len = strlen(attr);
        for (;;) {
                const char *space = strchrnul(attrs, ' ');
                if (len == space - attrs && !strncmp(attrs, attr, len))
                        return 1;
                if (!*space)
                        return 0;
                attrs = space + 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);

        if (data->push && for_push)
                write_str_in_full(helper->in, "list for-push\n");
        else
                write_str_in_full(helper->in, "list\n");

        while (1) {
                char *eov, *eon;
                recvline(data, &buf);

                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);
                if (eon) {
                        if (has_attribute(eon + 1, "unchanged")) {
                                (*tail)->status |= REF_STATUS_UPTODATE;
                                read_ref((*tail)->name, (*tail)->old_sha1);
                        }
                }
                tail = &((*tail)->next);
        }
        if (debug)
                fprintf(stderr, "Debug: Read ref listing.\n");
        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;

        if (getenv("GIT_TRANSPORT_HELPER_DEBUG"))
                debug = 1;

        transport->data = data;
        transport->set_option = set_helper_option;
        transport->get_refs_list = get_refs_list;
        transport->fetch = fetch;
        transport->push_refs = push_refs;
        transport->disconnect = release_helper;
        return 0;
}