/*
 * Licensed under a two-clause BSD-style license.
 * See LICENSE for details.
 */

#include "git-compat-util.h"
#include "fast_export.h"
#include "line_buffer.h"
#include "repo_tree.h"
#include "string_pool.h"
#include "strbuf.h"

#define MAX_GITSVN_LINE_LEN 4096

static uint32_t first_commit_done;
static struct line_buffer report_buffer = LINE_BUFFER_INIT;

void fast_export_init(int fd)
{
        if (buffer_fdinit(&report_buffer, fd))
                die_errno("cannot read from file descriptor %d", fd);
}

void fast_export_deinit(void)
{
        if (buffer_deinit(&report_buffer))
                die_errno("error closing fast-import feedback stream");
}

void fast_export_reset(void)
{
        buffer_reset(&report_buffer);
}

void fast_export_delete(uint32_t depth, const uint32_t *path)
{
        putchar('D');
        putchar(' ');
        pool_print_seq(depth, path, '/', stdout);
        putchar('\n');
}

static void fast_export_truncate(uint32_t depth, const uint32_t *path, uint32_t mode)
{
        fast_export_modify(depth, path, mode, "inline");
        printf("data 0\n\n");
}

void fast_export_modify(uint32_t depth, const uint32_t *path, uint32_t mode,
                        const char *dataref)
{
        /* Mode must be 100644, 100755, 120000, or 160000. */
        if (!dataref) {
                fast_export_truncate(depth, path, mode);
                return;
        }
        printf("M %06"PRIo32" %s ", mode, dataref);
        pool_print_seq(depth, path, '/', stdout);
        putchar('\n');
}

static char gitsvnline[MAX_GITSVN_LINE_LEN];
void fast_export_begin_commit(uint32_t revision, uint32_t author, char *log,
                        uint32_t uuid, uint32_t url,
                        unsigned long timestamp)
{
        if (!log)
                log = "";
        if (~uuid && ~url) {
                snprintf(gitsvnline, MAX_GITSVN_LINE_LEN,
                                "\n\ngit-svn-id: %s@%"PRIu32" %s\n",
                                 pool_fetch(url), revision, pool_fetch(uuid));
        } else {
                *gitsvnline = '\0';
        }
        printf("commit refs/heads/master\n");
        printf("mark :%"PRIu32"\n", revision);
        printf("committer %s <%s@%s> %ld +0000\n",
                   ~author ? pool_fetch(author) : "nobody",
                   ~author ? pool_fetch(author) : "nobody",
                   ~uuid ? pool_fetch(uuid) : "local", timestamp);
        printf("data %"PRIu32"\n%s%s\n",
                   (uint32_t) (strlen(log) + strlen(gitsvnline)),
                   log, gitsvnline);
        if (!first_commit_done) {
                if (revision > 1)
                        printf("from refs/heads/master^0\n");
                first_commit_done = 1;
        }
}

void fast_export_end_commit(uint32_t revision)
{
        printf("progress Imported commit %"PRIu32".\n\n", revision);
}

static void ls_from_rev(uint32_t rev, uint32_t depth, const uint32_t *path)
{
        /* ls :5 path/to/old/file */
        printf("ls :%"PRIu32" ", rev);
        pool_print_seq(depth, path, '/', stdout);
        putchar('\n');
        fflush(stdout);
}

static void ls_from_active_commit(uint32_t depth, const uint32_t *path)
{
        /* ls "path/to/file" */
        printf("ls \"");
        pool_print_seq(depth, path, '/', stdout);
        printf("\"\n");
        fflush(stdout);
}

static const char *get_response_line(void)
{
        const char *line = buffer_read_line(&report_buffer);
        if (line)
                return line;
        if (buffer_ferror(&report_buffer))
                die_errno("error reading from fast-import");
        die("unexpected end of fast-import feedback");
}

void fast_export_data(uint32_t mode, uint32_t len, struct line_buffer *input)
{
        if (mode == REPO_MODE_LNK) {
                /* svn symlink blobs start with "link " */
                buffer_skip_bytes(input, 5);
                len -= 5;
        }
        printf("data %"PRIu32"\n", len);
        buffer_copy_bytes(input, len);
        fputc('\n', stdout);
}

static int parse_ls_response(const char *response, uint32_t *mode,
                                        struct strbuf *dataref)
{
        const char *tab;
        const char *response_end;

        assert(response);
        response_end = response + strlen(response);

        if (*response == 'm') { /* Missing. */
                errno = ENOENT;
                return -1;
        }

        /* Mode. */
        if (response_end - response < strlen("100644") ||
            response[strlen("100644")] != ' ')
                die("invalid ls response: missing mode: %s", response);
        *mode = 0;
        for (; *response != ' '; response++) {
                char ch = *response;
                if (ch < '0' || ch > '7')
                        die("invalid ls response: mode is not octal: %s", response);
                *mode *= 8;
                *mode += ch - '0';
        }

        /* ' blob ' or ' tree ' */
        if (response_end - response < strlen(" blob ") ||
            (response[1] != 'b' && response[1] != 't'))
                die("unexpected ls response: not a tree or blob: %s", response);
        response += strlen(" blob ");

        /* Dataref. */
        tab = memchr(response, '\t', response_end - response);
        if (!tab)
                die("invalid ls response: missing tab: %s", response);
        strbuf_add(dataref, response, tab - response);
        return 0;
}

int fast_export_ls_rev(uint32_t rev, uint32_t depth, const uint32_t *path,
                                uint32_t *mode, struct strbuf *dataref)
{
        ls_from_rev(rev, depth, path);
        return parse_ls_response(get_response_line(), mode, dataref);
}

int fast_export_ls(uint32_t depth, const uint32_t *path,
                                uint32_t *mode, struct strbuf *dataref)
{
        ls_from_active_commit(depth, path);
        return parse_ls_response(get_response_line(), mode, dataref);
}