/*
 * mirror.c: Use a transparent proxy to mirror Subversion instances.
 *
 * ====================================================================
 * Copyright (c) 2000-2004 CollabNet.  All rights reserved.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution.  The terms
 * are also available at http://subversion.tigris.org/license-1.html.
 * If newer versions of this license are posted there, you may use a
 * newer version instead, at your option.
 *
 * This software consists of voluntary contributions made by many
 * individuals.  For exact contribution history, see the revision
 * history and logs, available at http://subversion.tigris.org/.
 * ====================================================================
 */

#include <apr_strmatch.h>

#include <httpd.h>
#include <http_core.h>

#include "dav_svn.h"

int dav_svn__proxy_merge_fixup(request_rec *r)
{
    const char *root_dir, *master_uri;

    root_dir = dav_svn__get_root_dir(r);
    master_uri = dav_svn__get_master_uri(r);

    if (root_dir && master_uri) {
        const char *seg;

        /* We know we can always safely handle these. */
        if (r->method_number == M_PROPFIND ||
            r->method_number == M_GET ||
            r->method_number == M_REPORT ||
            r->method_number == M_OPTIONS) {
            return OK;
        }

        seg = ap_strstr(r->unparsed_uri, root_dir);
        if (seg && (r->method_number == M_MERGE ||
            ap_strstr_c(seg, dav_svn__get_special_uri(r)))) {
            seg += strlen(root_dir);

            r->proxyreq = PROXYREQ_REVERSE;
            r->uri = r->unparsed_uri;
            r->filename = apr_pstrcat(r->pool, "proxy:", master_uri,
                                      "/", seg, NULL);
            r->handler = "proxy-server";
            ap_add_output_filter("LocationRewrite", NULL, r, r->connection);
            ap_add_output_filter("ReposRewrite", NULL, r, r->connection);
            ap_add_input_filter("IncomingRewrite", NULL, r, r->connection);
        }
    }
    return OK;
}

typedef struct locate_ctx_t
{
    const apr_strmatch_pattern *pattern;
    apr_size_t pattern_len;
    apr_uri_t uri;
    const char *localpath;
    apr_size_t  localpath_len;
    const char *remotepath;
    apr_size_t  remotepath_len;
} locate_ctx_t;

apr_status_t dav_svn__location_in_filter(ap_filter_t *f,
                                         apr_bucket_brigade *bb,
                                         ap_input_mode_t mode,
                                         apr_read_type_e block,
                                         apr_off_t readbytes)
{
    request_rec *r = f->r;
    locate_ctx_t *ctx = f->ctx;
    apr_status_t rv;
    apr_bucket *bkt;
    const char *master_uri;

    master_uri = dav_svn__get_master_uri(r);

    if (r->main || !master_uri) {
        ap_remove_input_filter(f);
        return ap_get_brigade(f->next, bb, mode, block, readbytes);
    }

    if (!f->ctx) {
        ctx = f->ctx = apr_pcalloc(r->pool, sizeof(*ctx));

        apr_uri_parse(r->pool, master_uri, &ctx->uri);
        ctx->remotepath = ctx->uri.path;
        ctx->remotepath_len = strlen(ctx->remotepath);
        ctx->localpath = dav_svn__get_root_dir(r);
        ctx->localpath_len = strlen(ctx->localpath);
        ctx->pattern = apr_strmatch_precompile(r->pool, ctx->localpath, 0);
        ctx->pattern_len = ctx->localpath_len;
    }

    rv = ap_get_brigade(f->next, bb, mode, block, readbytes);
    if (rv) {
        return rv;
    }

    bkt = APR_BRIGADE_FIRST(bb);
    while (bkt != APR_BRIGADE_SENTINEL(bb)) {

        const char *data, *match;
        apr_size_t len;

        if (APR_BUCKET_IS_METADATA(bkt)) {
            bkt = APR_BUCKET_NEXT(bkt);
            continue;
        }

        /* read */
        apr_bucket_read(bkt, &data, &len, APR_BLOCK_READ);
        match = apr_strmatch(ctx->pattern, data, len);
        if (match) {
            apr_bucket *next_bucket;
            apr_bucket_split(bkt, match - data);
            next_bucket = APR_BUCKET_NEXT(bkt);
            apr_bucket_split(next_bucket, ctx->pattern_len);
            bkt = APR_BUCKET_NEXT(next_bucket);
            apr_bucket_delete(next_bucket);
            next_bucket = apr_bucket_pool_create(ctx->remotepath,
                                                 ctx->remotepath_len,
                                                 r->pool, bb->bucket_alloc);
            APR_BUCKET_INSERT_BEFORE(bkt, next_bucket);
        }
        else {
            bkt = APR_BUCKET_NEXT(bkt);
        }
    }
    return APR_SUCCESS;
}

apr_status_t dav_svn__location_header_filter(ap_filter_t *f,
                                             apr_bucket_brigade *bb)
{
    request_rec *r = f->r;
    const char *master_uri;

    master_uri = dav_svn__get_master_uri(r);

    if (!r->main && master_uri) {
        const char *location, *start_foo = NULL;

        location = apr_table_get(r->headers_out, "Location");
        if (location) {
            start_foo = ap_strstr_c(location, master_uri);
        }
        if (start_foo) {
            const char *new_uri;
            start_foo += strlen(master_uri);
            new_uri = ap_construct_url(r->pool,
                                       apr_pstrcat(r->pool,
                                                   dav_svn__get_root_dir(r),
                                                   start_foo, NULL),
                                       r);
            apr_table_set(r->headers_out, "Location", new_uri);
        }
    }
    ap_remove_output_filter(f);
    return ap_pass_brigade(f->next, bb);
}

apr_status_t dav_svn__location_body_filter(ap_filter_t *f,
                                           apr_bucket_brigade *bb)
{
    request_rec *r = f->r;
    locate_ctx_t *ctx = f->ctx;
    apr_bucket *bkt;
    const char *master_uri;

    master_uri = dav_svn__get_master_uri(r);

    if (r->main || !master_uri) {
        ap_remove_output_filter(f);
        return ap_pass_brigade(f->next, bb);
    }

    if (!f->ctx) {
        ctx = f->ctx = apr_pcalloc(r->pool, sizeof(*ctx));

        apr_uri_parse(r->pool, master_uri, &ctx->uri);
        ctx->remotepath = ctx->uri.path;
        ctx->remotepath_len = strlen(ctx->remotepath);
        ctx->localpath = dav_svn__get_root_dir(r);
        ctx->localpath_len = strlen(ctx->localpath);
        ctx->pattern = apr_strmatch_precompile(r->pool, ctx->remotepath, 0);
        ctx->pattern_len = ctx->remotepath_len;
    }

    bkt = APR_BRIGADE_FIRST(bb);
    while (bkt != APR_BRIGADE_SENTINEL(bb)) {

        const char *data, *match;
        apr_size_t len;

        /* read */
        apr_bucket_read(bkt, &data, &len, APR_BLOCK_READ);
        match = apr_strmatch(ctx->pattern, data, len);
        if (match) {
            apr_bucket *next_bucket;
            apr_bucket_split(bkt, match - data);
            next_bucket = APR_BUCKET_NEXT(bkt);
            apr_bucket_split(next_bucket, ctx->pattern_len);
            bkt = APR_BUCKET_NEXT(next_bucket);
            apr_bucket_delete(next_bucket);
            next_bucket = apr_bucket_pool_create(ctx->localpath,
                                                 ctx->localpath_len,
                                                 r->pool, bb->bucket_alloc);
            APR_BUCKET_INSERT_BEFORE(bkt, next_bucket);
        }
        else {
            bkt = APR_BUCKET_NEXT(bkt);
        }
    }
    return ap_pass_brigade(f->next, bb);
}