#include "cache.h"
#include "commit.h"

#include "pull.h"

#include <curl/curl.h>
#include <curl/easy.h>

#if LIBCURL_VERSION_NUM < 0x070704
#define curl_global_cleanup() do { /* nothing */ } while(0)
#endif
#if LIBCURL_VERSION_NUM < 0x070800
#define curl_global_init(a) do { /* nothing */ } while(0)
#endif
#if LIBCURL_VERSION_NUM < 0x070907
#define curl_easy_setopt(a, b, c) do { /* nothing */ } while(0)
#endif

static CURL *curl;

static char *base;

static SHA_CTX c;
static z_stream stream;

static int local;
static int zret;

static int curl_ssl_verify;

struct buffer
{
        size_t posn;
        size_t size;
        void *buffer;
};

static size_t fwrite_buffer(void *ptr, size_t eltsize, size_t nmemb,
                            struct buffer *buffer) {
        size_t size = eltsize * nmemb;
        if (size > buffer->size - buffer->posn)
                size = buffer->size - buffer->posn;
        memcpy(buffer->buffer + buffer->posn, ptr, size);
        buffer->posn += size;
        return size;
}

static size_t fwrite_sha1_file(void *ptr, size_t eltsize, size_t nmemb, 
                               void *data) {
        unsigned char expn[4096];
        size_t size = eltsize * nmemb;
        int posn = 0;
        do {
                ssize_t retval = write(local, ptr + posn, size - posn);
                if (retval < 0)
                        return posn;
                posn += retval;
        } while (posn < size);

        stream.avail_in = size;
        stream.next_in = ptr;
        do {
                stream.next_out = expn;
                stream.avail_out = sizeof(expn);
                zret = inflate(&stream, Z_SYNC_FLUSH);
                SHA1_Update(&c, expn, sizeof(expn) - stream.avail_out);
        } while (stream.avail_in && zret == Z_OK);
        return size;
}

int fetch(unsigned char *sha1)
{
        char *hex = sha1_to_hex(sha1);
        char *filename = sha1_file_name(sha1);
        unsigned char real_sha1[20];
        char *url;
        char *posn;

        local = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);

        if (local < 0)
                return error("Couldn't open %s\n", filename);

        memset(&stream, 0, sizeof(stream));

        inflateInit(&stream);

        SHA1_Init(&c);

        curl_easy_setopt(curl, CURLOPT_FILE, NULL);
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);

        url = xmalloc(strlen(base) + 50);
        strcpy(url, base);
        posn = url + strlen(base);
        strcpy(posn, "objects/");
        posn += 8;
        memcpy(posn, hex, 2);
        posn += 2;
        *(posn++) = '/';
        strcpy(posn, hex + 2);

        curl_easy_setopt(curl, CURLOPT_URL, url);

        if (curl_easy_perform(curl))
                return error("Couldn't get %s for %s\n", url, hex);

        close(local);
        inflateEnd(&stream);
        SHA1_Final(real_sha1, &c);
        if (zret != Z_STREAM_END) {
                unlink(filename);
                return error("File %s (%s) corrupt\n", hex, url);
        }
        if (memcmp(sha1, real_sha1, 20)) {
                unlink(filename);
                return error("File %s has bad hash\n", hex);
        }
        
        pull_say("got %s\n", hex);
        return 0;
}

int fetch_ref(char *ref, unsigned char *sha1)
{
        char *url, *posn;
        char hex[42];
        struct buffer buffer;
        buffer.size = 41;
        buffer.posn = 0;
        buffer.buffer = hex;
        hex[41] = '\0';
        
        curl_easy_setopt(curl, CURLOPT_FILE, &buffer);
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);

        url = xmalloc(strlen(base) + 6 + strlen(ref));
        strcpy(url, base);
        posn = url + strlen(base);
        strcpy(posn, "refs/");
        posn += 5;
        strcpy(posn, ref);

        curl_easy_setopt(curl, CURLOPT_URL, url);

        if (curl_easy_perform(curl))
                return error("Couldn't get %s for %s\n", url, ref);

        hex[40] = '\0';
        get_sha1_hex(hex, sha1);
        return 0;
}

int main(int argc, char **argv)
{
        char *commit_id;
        char *url;
        int arg = 1;

        while (arg < argc && argv[arg][0] == '-') {
                if (argv[arg][1] == 't') {
                        get_tree = 1;
                } else if (argv[arg][1] == 'c') {
                        get_history = 1;
                } else if (argv[arg][1] == 'a') {
                        get_all = 1;
                        get_tree = 1;
                        get_history = 1;
                } else if (argv[arg][1] == 'v') {
                        get_verbosely = 1;
                } else if (argv[arg][1] == 'w') {
                        write_ref = argv[arg + 1];
                        arg++;
                }
                arg++;
        }
        if (argc < arg + 2) {
                usage("git-http-pull [-c] [-t] [-a] [-d] [-v] [--recover] [-w ref] commit-id url");
                return 1;
        }
        commit_id = argv[arg];
        url = argv[arg + 1];

        curl_global_init(CURL_GLOBAL_ALL);

        curl = curl_easy_init();

        curl_ssl_verify = gitenv("GIT_SSL_NO_VERIFY") ? 0 : 1;
        curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, curl_ssl_verify);
        curl_easy_setopt(curl, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);

        base = url;

        if (pull(commit_id))
                return 1;

        curl_global_cleanup();
        return 0;
}