#include "cache.h"
#include "remote.h"
#include "strbuf.h"
#include "walker.h"
#include "http.h"
#include "exec_cmd.h"
#include "run-command.h"
#include "pkt-line.h"
#include "sideband.h"

static struct remote *remote;
static const char *url;
static struct walker *walker;

struct options {
        int verbosity;
        unsigned long depth;
        unsigned progress : 1,
                followtags : 1,
                dry_run : 1,
                thin : 1;
};
static struct options options;

static void init_walker(void)
{
        if (!walker)
                walker = get_http_walker(url, remote);
}

static int set_option(const char *name, const char *value)
{
        if (!strcmp(name, "verbosity")) {
                char *end;
                int v = strtol(value, &end, 10);
                if (value == end || *end)
                        return -1;
                options.verbosity = v;
                return 0;
        }
        else if (!strcmp(name, "progress")) {
                if (!strcmp(value, "true"))
                        options.progress = 1;
                else if (!strcmp(value, "false"))
                        options.progress = 0;
                else
                        return -1;
                return 1 /* TODO implement later */;
        }
        else if (!strcmp(name, "depth")) {
                char *end;
                unsigned long v = strtoul(value, &end, 10);
                if (value == end || *end)
                        return -1;
                options.depth = v;
                return 1 /* TODO implement later */;
        }
        else if (!strcmp(name, "followtags")) {
                if (!strcmp(value, "true"))
                        options.followtags = 1;
                else if (!strcmp(value, "false"))
                        options.followtags = 0;
                else
                        return -1;
                return 1 /* TODO implement later */;
        }
        else if (!strcmp(name, "dry-run")) {
                if (!strcmp(value, "true"))
                        options.dry_run = 1;
                else if (!strcmp(value, "false"))
                        options.dry_run = 0;
                else
                        return -1;
                return 0;
        }
        else {
                return 1 /* unsupported */;
        }
}

struct discovery {
        const char *service;
        char *buf_alloc;
        char *buf;
        size_t len;
        unsigned proto_git : 1;
};
static struct discovery *last_discovery;

static void free_discovery(struct discovery *d)
{
        if (d) {
                if (d == last_discovery)
                        last_discovery = NULL;
                free(d->buf_alloc);
                free(d);
        }
}

static struct discovery* discover_refs(const char *service)
{
        struct strbuf buffer = STRBUF_INIT;
        struct discovery *last = last_discovery;
        char *refs_url;
        int http_ret, is_http = 0;

        if (last && !strcmp(service, last->service))
                return last;
        free_discovery(last);

        strbuf_addf(&buffer, "%s/info/refs", url);
        if (!prefixcmp(url, "http://") || !prefixcmp(url, "https://")) {
                is_http = 1;
                if (!strchr(url, '?'))
                        strbuf_addch(&buffer, '?');
                else
                        strbuf_addch(&buffer, '&');
                strbuf_addf(&buffer, "service=%s", service);
        }
        refs_url = strbuf_detach(&buffer, NULL);

        init_walker();
        http_ret = http_get_strbuf(refs_url, &buffer, HTTP_NO_CACHE);
        switch (http_ret) {
        case HTTP_OK:
                break;
        case HTTP_MISSING_TARGET:
                die("%s not found: did you run git update-server-info on the"
                    " server?", refs_url);
        default:
                http_error(refs_url, http_ret);
                die("HTTP request failed");
        }

        last= xcalloc(1, sizeof(*last_discovery));
        last->service = service;
        last->buf_alloc = strbuf_detach(&buffer, &last->len);
        last->buf = last->buf_alloc;

        if (is_http && 5 <= last->len && last->buf[4] == '#') {
                /* smart HTTP response; validate that the service
                 * pkt-line matches our request.
                 */
                struct strbuf exp = STRBUF_INIT;

                if (packet_get_line(&buffer, &last->buf, &last->len) <= 0)
                        die("%s has invalid packet header", refs_url);
                if (buffer.len && buffer.buf[buffer.len - 1] == '\n')
                        strbuf_setlen(&buffer, buffer.len - 1);

                strbuf_addf(&exp, "# service=%s", service);
                if (strbuf_cmp(&exp, &buffer))
                        die("invalid server response; got '%s'", buffer.buf);
                strbuf_release(&exp);

                /* The header can include additional metadata lines, up
                 * until a packet flush marker.  Ignore these now, but
                 * in the future we might start to scan them.
                 */
                strbuf_reset(&buffer);
                while (packet_get_line(&buffer, &last->buf, &last->len) > 0)
                        strbuf_reset(&buffer);

                last->proto_git = 1;
        }

        free(refs_url);
        strbuf_release(&buffer);
        last_discovery = last;
        return last;
}

static int write_discovery(int fd, void *data)
{
        struct discovery *heads = data;
        int err = 0;
        if (write_in_full(fd, heads->buf, heads->len) != heads->len)
                err = 1;
        close(fd);
        return err;
}

static struct ref *parse_git_refs(struct discovery *heads)
{
        struct ref *list = NULL;
        struct async async;

        memset(&async, 0, sizeof(async));
        async.proc = write_discovery;
        async.data = heads;

        if (start_async(&async))
                die("cannot start thread to parse advertised refs");
        get_remote_heads(async.out, &list, 0, NULL, 0, NULL);
        close(async.out);
        if (finish_async(&async))
                die("ref parsing thread failed");
        return list;
}

static struct ref *parse_info_refs(struct discovery *heads)
{
        char *data, *start, *mid;
        char *ref_name;
        int i = 0;

        struct ref *refs = NULL;
        struct ref *ref = NULL;
        struct ref *last_ref = NULL;

        data = heads->buf;
        start = NULL;
        mid = data;
        while (i < heads->len) {
                if (!start) {
                        start = &data[i];
                }
                if (data[i] == '\t')
                        mid = &data[i];
                if (data[i] == '\n') {
                        data[i] = 0;
                        ref_name = mid + 1;
                        ref = xmalloc(sizeof(struct ref) +
                                      strlen(ref_name) + 1);
                        memset(ref, 0, sizeof(struct ref));
                        strcpy(ref->name, ref_name);
                        get_sha1_hex(start, ref->old_sha1);
                        if (!refs)
                                refs = ref;
                        if (last_ref)
                                last_ref->next = ref;
                        last_ref = ref;
                        start = NULL;
                }
                i++;
        }

        init_walker();
        ref = alloc_ref("HEAD");
        if (!walker->fetch_ref(walker, ref) &&
            !resolve_remote_symref(ref, refs)) {
                ref->next = refs;
                refs = ref;
        } else {
                free(ref);
        }

        return refs;
}

static struct ref *get_refs(int for_push)
{
        struct discovery *heads;

        if (for_push)
                heads = discover_refs("git-receive-pack");
        else
                heads = discover_refs("git-upload-pack");

        if (heads->proto_git)
                return parse_git_refs(heads);
        return parse_info_refs(heads);
}

static void output_refs(struct ref *refs)
{
        struct ref *posn;
        for (posn = refs; posn; posn = posn->next) {
                if (posn->symref)
                        printf("@%s %s\n", posn->symref, posn->name);
                else
                        printf("%s %s\n", sha1_to_hex(posn->old_sha1), posn->name);
        }
        printf("\n");
        fflush(stdout);
        free_refs(refs);
}

struct rpc_state {
        const char *service_name;
        const char **argv;
        char *service_url;
        char *hdr_content_type;
        char *hdr_accept;
        char *buf;
        size_t alloc;
        size_t len;
        size_t pos;
        int in;
        int out;
        struct strbuf result;
};

static size_t rpc_out(void *ptr, size_t eltsize,
                size_t nmemb, void *buffer_)
{
        size_t max = eltsize * nmemb;
        struct rpc_state *rpc = buffer_;
        size_t avail = rpc->len - rpc->pos;

        if (!avail) {
                avail = packet_read_line(rpc->out, rpc->buf, rpc->alloc);
                if (!avail)
                        return 0;
                rpc->pos = 0;
                rpc->len = avail;
        }

        if (max < avail);
                avail = max;
        memcpy(ptr, rpc->buf + rpc->pos, avail);
        rpc->pos += avail;
        return avail;
}

static size_t rpc_in(const void *ptr, size_t eltsize,
                size_t nmemb, void *buffer_)
{
        size_t size = eltsize * nmemb;
        struct rpc_state *rpc = buffer_;
        write_or_die(rpc->in, ptr, size);
        return size;
}

static int post_rpc(struct rpc_state *rpc)
{
        struct active_request_slot *slot;
        struct slot_results results;
        struct curl_slist *headers = NULL;
        int err = 0, large_request = 0;

        /* Try to load the entire request, if we can fit it into the
         * allocated buffer space we can use HTTP/1.0 and avoid the
         * chunked encoding mess.
         */
        while (1) {
                size_t left = rpc->alloc - rpc->len;
                char *buf = rpc->buf + rpc->len;
                int n;

                if (left < LARGE_PACKET_MAX) {
                        large_request = 1;
                        break;
                }

                n = packet_read_line(rpc->out, buf, left);
                if (!n)
                        break;
                rpc->len += n;
        }

        slot = get_active_slot();
        slot->results = &results;

        curl_easy_setopt(slot->curl, CURLOPT_POST, 1);
        curl_easy_setopt(slot->curl, CURLOPT_NOBODY, 0);
        curl_easy_setopt(slot->curl, CURLOPT_URL, rpc->service_url);

        headers = curl_slist_append(headers, rpc->hdr_content_type);
        headers = curl_slist_append(headers, rpc->hdr_accept);

        if (large_request) {
                /* The request body is large and the size cannot be predicted.
                 * We must use chunked encoding to send it.
                 */
                headers = curl_slist_append(headers, "Expect: 100-continue");
                headers = curl_slist_append(headers, "Transfer-Encoding: chunked");
                curl_easy_setopt(slot->curl, CURLOPT_READFUNCTION, rpc_out);
                curl_easy_setopt(slot->curl, CURLOPT_INFILE, rpc);
                if (options.verbosity > 1) {
                        fprintf(stderr, "POST %s (chunked)\n", rpc->service_name);
                        fflush(stderr);
                }

        } else {
                /* We know the complete request size in advance, use the
                 * more normal Content-Length approach.
                 */
                curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDS, rpc->buf);
                curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDSIZE, rpc->len);
                if (options.verbosity > 1) {
                        fprintf(stderr, "POST %s (%lu bytes)\n",
                                rpc->service_name, (unsigned long)rpc->len);
                        fflush(stderr);
                }
        }

        curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, headers);
        curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, rpc_in);
        curl_easy_setopt(slot->curl, CURLOPT_FILE, rpc);

        slot->curl_result = curl_easy_perform(slot->curl);
        finish_active_slot(slot);

        if (results.curl_result != CURLE_OK) {
                err |= error("RPC failed; result=%d, HTTP code = %ld",
                        results.curl_result, results.http_code);
        }

        curl_slist_free_all(headers);
        return err;
}

static int rpc_service(struct rpc_state *rpc, struct discovery *heads)
{
        const char *svc = rpc->service_name;
        struct strbuf buf = STRBUF_INIT;
        struct child_process client;
        int err = 0;

        init_walker();
        memset(&client, 0, sizeof(client));
        client.in = -1;
        client.out = -1;
        client.git_cmd = 1;
        client.argv = rpc->argv;
        if (start_command(&client))
                exit(1);
        if (heads)
                write_or_die(client.in, heads->buf, heads->len);

        rpc->alloc = http_post_buffer;
        rpc->buf = xmalloc(rpc->alloc);
        rpc->in = client.in;
        rpc->out = client.out;
        strbuf_init(&rpc->result, 0);

        strbuf_addf(&buf, "%s/%s", url, svc);
        rpc->service_url = strbuf_detach(&buf, NULL);

        strbuf_addf(&buf, "Content-Type: application/x-%s-request", svc);
        rpc->hdr_content_type = strbuf_detach(&buf, NULL);

        strbuf_addf(&buf, "Accept: application/x-%s-response", svc);
        rpc->hdr_accept = strbuf_detach(&buf, NULL);

        while (!err) {
                int n = packet_read_line(rpc->out, rpc->buf, rpc->alloc);
                if (!n)
                        break;
                rpc->pos = 0;
                rpc->len = n;
                err |= post_rpc(rpc);
        }
        strbuf_read(&rpc->result, client.out, 0);

        close(client.in);
        close(client.out);
        client.in = -1;
        client.out = -1;

        err |= finish_command(&client);
        free(rpc->service_url);
        free(rpc->hdr_content_type);
        free(rpc->hdr_accept);
        free(rpc->buf);
        strbuf_release(&buf);
        return err;
}

static int fetch_dumb(int nr_heads, struct ref **to_fetch)
{
        char **targets = xmalloc(nr_heads * sizeof(char*));
        int ret, i;

        for (i = 0; i < nr_heads; i++)
                targets[i] = xstrdup(sha1_to_hex(to_fetch[i]->old_sha1));

        init_walker();
        walker->get_all = 1;
        walker->get_tree = 1;
        walker->get_history = 1;
        walker->get_verbosely = options.verbosity >= 3;
        walker->get_recover = 0;
        ret = walker_fetch(walker, nr_heads, targets, NULL, NULL);

        for (i = 0; i < nr_heads; i++)
                free(targets[i]);
        free(targets);

        return ret ? error("Fetch failed.") : 0;
}

static void parse_fetch(struct strbuf *buf)
{
        struct ref **to_fetch = NULL;
        struct ref *list_head = NULL;
        struct ref **list = &list_head;
        int alloc_heads = 0, nr_heads = 0;

        do {
                if (!prefixcmp(buf->buf, "fetch ")) {
                        char *p = buf->buf + strlen("fetch ");
                        char *name;
                        struct ref *ref;
                        unsigned char old_sha1[20];

                        if (strlen(p) < 40 || get_sha1_hex(p, old_sha1))
                                die("protocol error: expected sha/ref, got %s'", p);
                        if (p[40] == ' ')
                                name = p + 41;
                        else if (!p[40])
                                name = "";
                        else
                                die("protocol error: expected sha/ref, got %s'", p);

                        ref = alloc_ref(name);
                        hashcpy(ref->old_sha1, old_sha1);

                        *list = ref;
                        list = &ref->next;

                        ALLOC_GROW(to_fetch, nr_heads + 1, alloc_heads);
                        to_fetch[nr_heads++] = ref;
                }
                else
                        die("http transport does not support %s", buf->buf);

                strbuf_reset(buf);
                if (strbuf_getline(buf, stdin, '\n') == EOF)
                        return;
                if (!*buf->buf)
                        break;
        } while (1);

        if (fetch_dumb(nr_heads, to_fetch))
                exit(128); /* error already reported */
        free_refs(list_head);
        free(to_fetch);

        printf("\n");
        fflush(stdout);
        strbuf_reset(buf);
}

static int push_dav(int nr_spec, char **specs)
{
        const char **argv = xmalloc((10 + nr_spec) * sizeof(char*));
        int argc = 0, i;

        argv[argc++] = "http-push";
        argv[argc++] = "--helper-status";
        if (options.dry_run)
                argv[argc++] = "--dry-run";
        if (options.verbosity > 1)
                argv[argc++] = "--verbose";
        argv[argc++] = url;
        for (i = 0; i < nr_spec; i++)
                argv[argc++] = specs[i];
        argv[argc++] = NULL;

        if (run_command_v_opt(argv, RUN_GIT_CMD))
                die("git-%s failed", argv[0]);
        free(argv);
        return 0;
}

static int push_git(struct discovery *heads, int nr_spec, char **specs)
{
        struct rpc_state rpc;
        const char **argv;
        int argc = 0, i, err;

        argv = xmalloc((10 + nr_spec) * sizeof(char*));
        argv[argc++] = "send-pack";
        argv[argc++] = "--stateless-rpc";
        argv[argc++] = "--helper-status";
        if (options.thin)
                argv[argc++] = "--thin";
        if (options.dry_run)
                argv[argc++] = "--dry-run";
        if (options.verbosity > 1)
                argv[argc++] = "--verbose";
        argv[argc++] = url;
        for (i = 0; i < nr_spec; i++)
                argv[argc++] = specs[i];
        argv[argc++] = NULL;

        memset(&rpc, 0, sizeof(rpc));
        rpc.service_name = "git-receive-pack",
        rpc.argv = argv;

        err = rpc_service(&rpc, heads);
        if (rpc.result.len)
                safe_write(1, rpc.result.buf, rpc.result.len);
        strbuf_release(&rpc.result);
        free(argv);
        return err;
}

static int push(int nr_spec, char **specs)
{
        struct discovery *heads = discover_refs("git-receive-pack");
        int ret;

        if (heads->proto_git)
                ret = push_git(heads, nr_spec, specs);
        else
                ret = push_dav(nr_spec, specs);
        free_discovery(heads);
        return ret;
}

static void parse_push(struct strbuf *buf)
{
        char **specs = NULL;
        int alloc_spec = 0, nr_spec = 0, i;

        do {
                if (!prefixcmp(buf->buf, "push ")) {
                        ALLOC_GROW(specs, nr_spec + 1, alloc_spec);
                        specs[nr_spec++] = xstrdup(buf->buf + 5);
                }
                else
                        die("http transport does not support %s", buf->buf);

                strbuf_reset(buf);
                if (strbuf_getline(buf, stdin, '\n') == EOF)
                        return;
                if (!*buf->buf)
                        break;
        } while (1);

        if (push(nr_spec, specs))
                exit(128); /* error already reported */
        for (i = 0; i < nr_spec; i++)
                free(specs[i]);
        free(specs);

        printf("\n");
        fflush(stdout);
}

int main(int argc, const char **argv)
{
        struct strbuf buf = STRBUF_INIT;

        git_extract_argv0_path(argv[0]);
        setup_git_directory();
        if (argc < 2) {
                fprintf(stderr, "Remote needed\n");
                return 1;
        }

        options.verbosity = 1;
        options.progress = !!isatty(2);
        options.thin = 1;

        remote = remote_get(argv[1]);

        if (argc > 2) {
                url = argv[2];
        } else {
                url = remote->url[0];
        }

        do {
                if (strbuf_getline(&buf, stdin, '\n') == EOF)
                        break;
                if (!prefixcmp(buf.buf, "fetch ")) {
                        parse_fetch(&buf);

                } else if (!strcmp(buf.buf, "list") || !prefixcmp(buf.buf, "list ")) {
                        int for_push = !!strstr(buf.buf + 4, "for-push");
                        output_refs(get_refs(for_push));

                } else if (!prefixcmp(buf.buf, "push ")) {
                        parse_push(&buf);

                } else if (!prefixcmp(buf.buf, "option ")) {
                        char *name = buf.buf + strlen("option ");
                        char *value = strchr(name, ' ');
                        int result;

                        if (value)
                                *value++ = '\0';
                        else
                                value = "true";

                        result = set_option(name, value);
                        if (!result)
                                printf("ok\n");
                        else if (result < 0)
                                printf("error invalid value\n");
                        else
                                printf("unsupported\n");
                        fflush(stdout);

                } else if (!strcmp(buf.buf, "capabilities")) {
                        printf("fetch\n");
                        printf("option\n");
                        printf("push\n");
                        printf("\n");
                        fflush(stdout);
                } else {
                        return 1;
                }
                strbuf_reset(&buf);
        } while (1);
        return 0;
}