#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_hunk.h>
#include <ngx_event_write.h>
#include <ngx_http.h>
#include <ngx_http_config.h>


static ngx_command_t ngx_http_ssi_filter_commands[];

static void *ngx_http_ssi_filter_create_conf(ngx_pool_t *pool);

ngx_http_module_t  ngx_http_ssi_filter_module = {
    NGX_HTTP_MODULE,
    NULL,                                  /* create server config */
    ngx_http_ssi_filter_create_conf,     /* create location config */
    ngx_http_ssi_filter_commands,        /* module directives */
    NULL,                                  /* init module */
    NULL                                   /* init output body filter */
};


static ngx_command_t ngx_http_ssi_filter_commands[] = {

    {"ssi", ngx_conf_set_size_slot,
     offsetof(ngx_http_write_filter_conf_t, buffer_output),
     NGX_HTTP_LOC_CONF, NGX_CONF_TAKE1, 
     "set write filter size to buffer output"},

    {NULL}

};


int ngx_http_ssi_filter(ngx_http_request_t *r, ngx_chain_t *in)
{
    int    last;
    off_t  size, flush;
    ngx_chain_t  *ch, **prev, *chain;
    ngx_http_ssi_filter_ctx_t  *ctx;
    ngx_http_ssi_filter_conf_t *conf;

    ctx = (ngx_http_ssi_filter_ctx_t *)
                              ngx_get_module_ctx(r->main ? r->main : r,
                                                 ngx_http_ssi_filter_module);
    if (ctx == NULL) {
        ngx_http_create_ctx(r, ctx,
                            ngx_http_ssi_filter_module,
                            sizeof(ngx_http_ssi_filter_ctx_t));

        ctx->state = &ssi_start;
    }

    state = ctx->state;

    ch = in;
    p = ch->hunk->pos.mem; 

    for ( ;; ) {

        if (state == ssi_start_state) {
            for (/* void */ ; p < ch->hunk->last.mem; p++) {
                if (*p == '<') {
                    state = ssi_exclam_state;
                    saved_pos = p;
                    saved_chain = ch;
                    break;
                }
            }
        }

        for (/* void */ ;
             p < ch->hunk->last.mem && state > ssi_start_state;
             p++)
        {

            if (*p == '<') {
                state = ssi_exclam_state;
                saved_pos = p;
                saved_chain = ch;
                continue;
            }

            switch (state) {

            case ssi_exclam_state:
                if (*p == '!') {
                    state = ssi_dash1_state;

                else {
                    state = ssi_ssi_state;
                    saved_pos = NULL;
                    saved_chain = NULL;
                }

                break;

            case ssi_dash1_state:
                if (*p == '-') {
                    state = ssi_dash2_state;

                else {
                    state = ssi_ssi_state;
                    saved_pos = NULL;
                    saved_chain = NULL;
                }

                break;

            case ssi_dash2_state:
                if (*p == '-') {
                    state = ssi_sharp_state;

                else {
                    state = ssi_ssi_state;
                    saved_pos = NULL;
                    saved_chain = NULL;
                }

                break;

            case ssi_sharp_state:
                switch (*p) {
                case '#':
                    state = ssi_command_state;
                    break;

                case ' ':
                case '\t':
                case CR:
                case LF:
                    break;

                default:
                    state = ssi_ssi_state;
                    saved_pos = NULL;
                    saved_chain = NULL;
                    break;
                }

                break;
            }
        }

        ch = ch->next;
        if (ch == NULL) {
            ctx->state = state;
            break;
        }

        p = ch->hunk->pos.mem; 
    }

    for (p = saved_pos, ch = saved_chain;
         ch;
         ch = ch->next, p = ch->hunk->pos.mem)
    {
        ngx_memcpy(saved_line, p, ch->hunk->last.mem - p);
        saved_size += ch->hunk->last.mem - p;
        if (ch->next == NULL)
             break;
    }














    for (/* void */; in; in = in->next) {

        for (p = in->hunk->pos.mem;
             in->hunk->pos.mem < in->hunk->last.mem;
             p++)
        {
            switch (state) {

            case ssi_start_state:
                if (*p == '<') {
                    state = ssi_exclam_state;
                    save_line = p;
                }
                break;

            case ssi_exclam_state:
            }
        }
    }



















    size = flush = 0;
    last = 0;
    prev = &ctx->out;

    /* find size, flush point and last link of saved chain */
    for (ch = ctx->out; ch; ch = ch->next) {
        prev = &ch->next;
        size += ch->hunk->last.file - ch->hunk->pos.file;

        ngx_log_debug(r->connection->log, "old chunk: %x " QX_FMT " " QD_FMT _
                      ch->hunk->type _ ch->hunk->pos.file _
                      ch->hunk->last.file - ch->hunk->pos.file);

        if (ch->hunk->type & NGX_HUNK_FLUSH|NGX_HUNK_RECYCLED)
            flush = size;

        if (ch->hunk->type & NGX_HUNK_LAST)
            last = 1;
    }

    /* add new chain to existent one */
    for (/* void */; in; in = in->next) {
        ngx_test_null(ch, ngx_palloc(r->pool, sizeof(ngx_chain_t)), NGX_ERROR);

        ch->hunk = in->hunk;
        ch->next = NULL;
        *prev = ch;
        prev = &ch->next;
        size += ch->hunk->last.file - ch->hunk->pos.file;

        ngx_log_debug(r->connection->log, "new chunk: %x " QX_FMT " " QD_FMT _
                      ch->hunk->type _ ch->hunk->pos.file _
                      ch->hunk->last.file - ch->hunk->pos.file);

        if (ch->hunk->type & NGX_HUNK_FLUSH|NGX_HUNK_RECYCLED)
            flush = size;

        if (ch->hunk->type & NGX_HUNK_LAST)
            last = 1;
    }

    conf = (ngx_http_write_filter_conf_t *)
                   ngx_get_module_loc_conf(r->main ? r->main : r,
                                                ngx_http_write_filter_module);

    if (!last && flush == 0 && size < conf->buffer_output)
        return NGX_OK;

    chain = ngx_event_write(r->connection, ctx->out, flush);
    if (chain == (ngx_chain_t *) -1)
        return NGX_ERROR;

    ctx->out = chain;

    ngx_log_debug(r->connection->log, "write filter %x" _ chain);

    return (chain ? NGX_AGAIN : NGX_OK);
}


static void *ngx_http_ssi_filter_create_conf(ngx_pool_t *pool)
{
    ngx_http_ssi_filter_conf_t *conf;

    ngx_test_null(conf,
                  ngx_palloc(pool, sizeof(ngx_http_ssi_filter_conf_t)),
                  NULL);

    conf->buffer_output = NGX_CONF_UNSET;

    return conf;
}