/*
**  OSSP cfg - Configuration Parsing
**  Copyright (c) 2002-2006 Ralf S. Engelschall <rse@engelschall.com>
**  Copyright (c) 2002-2006 The OSSP Project (http://www.ossp.org/)
**
**  This file is part of OSSP cfg, a configuration parsing
**  library which can be found at http://www.ossp.org/pkg/lib/cfg/.
**
**  Permission to use, copy, modify, and distribute this software for
**  any purpose with or without fee is hereby granted, provided that
**  the above copyright notice and this permission notice appear in all
**  copies.
**
**  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
**  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
**  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
**  IN NO EVENT SHALL THE AUTHORS AND COPYRIGHT HOLDERS AND THEIR
**  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
**  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
**  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
**  USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
**  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
**  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
**  OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
**  SUCH DAMAGE.
**
**  cfg_syn.c: syntax parsing and formatting
*/

#include <stdio.h>
#include <ctype.h>

#include "cfg.h"
#include "cfg_grid.h"
#include "cfg_node.h"
#include "cfg_fmt.h"
#include "cfg_syn.h"
#include "cfg_buf.h"
#include "cfg_global.h"

/* prototypes for Flex-generated scanner */
extern int  cfg_syn_lex_init(void *);
extern int  cfg_syn_lex_destroy(void *);
extern void cfg_syn_set_extra(void *, void *);

/* prototypes for Bison-generated parser */
extern int  cfg_syn_parse(void *);

/* build a node tree according to a textual specification */
cfg_rc_t cfg_syn_import(
    cfg_t *cfg,
    cfg_node_t **node,
    const char *in_ptr,
    size_t in_len,
    char *err_buf,
    size_t err_len)
{
    cfg_syn_ctx_t ctx;
    cfg_buf_t *buf;
    cfg_rc_t rc;
    void *yyscan;

    /* argument sanity checking */
    if (node == NULL || in_ptr == NULL)
        return CFG_ERR_ARG;

    /* initialize scanner */
    cfg_syn_lex_init(&yyscan);
    cfg_syn_set_extra(&ctx, yyscan);

    /* initialize temporary buffer context */
    if ((rc = cfg_buf_create(&buf)) != CFG_OK)
        return rc;

    /* establish our own context which is passed
       through the parser and scanner */
    ctx.inputptr = in_ptr;
    ctx.inputbuf = in_ptr;
    ctx.inputlen = in_len;
    ctx.cfg      = cfg;
    ctx.node     = NULL;
    ctx.rv       = CFG_OK;
    ctx.buf      = buf;
    ctx.err_buf  = err_buf;
    ctx.err_len  = err_len;
    ctx.yyscan   = yyscan;

    /* start the parser loop */
    if (cfg_syn_parse(&ctx))
        ctx.rv = (ctx.rv == CFG_OK ? CFG_ERR_INT : ctx.rv);

    /* destroy temporary buffer */
    cfg_buf_destroy(buf);

    /* destroy scanner */
    cfg_syn_lex_destroy(yyscan);

    /* provide root/top-level node as result */
    *node = ctx.node;

    return ctx.rv;
}

/* helper function for copying out input with escaping of characters */
static size_t cfg_syn_error_cpyout(char *out_ptr, const char *in_ptr, size_t in_len)
{
    size_t out_len;
    char c;

    out_len = 0;
    while (in_len-- > 0) {
        c = *in_ptr++;
        switch (c) {
            case '\n': *out_ptr++ = '\\'; *out_ptr++ = 'n'; out_len += 2; break;
            case '\r': *out_ptr++ = '\\'; *out_ptr++ = 'r'; out_len += 2; break;
            case '\t': *out_ptr++ = '\\'; *out_ptr++ = 't'; out_len += 2; break;
            case '\b': *out_ptr++ = '\\'; *out_ptr++ = 'b'; out_len += 2; break;
            case '\f': *out_ptr++ = '\\'; *out_ptr++ = 'f'; out_len += 2; break;
            default: {
                if (!isprint((int)c)) {
                    *out_ptr++ = '\\';
                    *out_ptr++ = '?';
                    out_len += 2;
                }
                else {
                    *out_ptr++ = c;
                    out_len++;
                }
            }
        }
    }
    return out_len;
}

/* remember a parsing error (used internally) */
void cfg_syn_error(cfg_syn_ctx_t *ctx, cfg_rc_t rv, YYLTYPE *loc, const char *fmt, ...)
{
    va_list ap;
    const char *cpF, *cpL;
    const char *cpP, *cpE;
    int line, column;
    char *cpBuf;
    char *cp;
    size_t n;

    /* remember error code */
    ctx->rv = rv;

    /* short circuit processing if no error buffer exists */
    if (ctx->err_buf == NULL || ctx->err_len <= 0)
        return;

    /* determine first and last positions of token */
    cpF = ctx->inputbuf+loc->first;
    if (cpF < ctx->inputbuf)
        cpF = ctx->inputbuf;
    if (cpF > ctx->inputbuf+ctx->inputlen)
        cpF = ctx->inputbuf+ctx->inputlen;
    cpL = ctx->inputbuf+loc->last;
    if (cpL < ctx->inputbuf)
        cpL = ctx->inputbuf;
    if (cpL > ctx->inputbuf+ctx->inputlen)
        cpL = ctx->inputbuf+ctx->inputlen;

    /* determine epilog and prolog of token */
    cpP = cpF-4;
    if (cpP < ctx->inputbuf)
        cpP = ctx->inputbuf;
    cpE = cpL+4;
    if (cpE > ctx->inputbuf+ctx->inputlen)
        cpE = ctx->inputbuf+ctx->inputlen;

    /* calculate line and column of token */
    line   = 1;
    column = 1;
    for (cp = (char *)ctx->inputbuf; cp < (ctx->inputbuf+ctx->inputlen) && cp != cpF; cp++) {
        column++;
        if (*cp == '\n') {
            column = 1;
            line++;
        }
    }

    /* extract token context with mark token borders */
    if ((cpBuf = malloc((size_t)(((cpE-cpP)*2)+2+1))) == NULL)
        return;
    cp = cpBuf;
    cp += cfg_syn_error_cpyout(cp, cpP, cpF-cpP);
    *cp++ = '<';
    cp += cfg_syn_error_cpyout(cp, cpF, cpL-cpF);
    *cp++ = '>';
    cp += cfg_syn_error_cpyout(cp, cpL, cpE-cpL);
    *cp++ = '\0';

    /* remember parsing error: part I (context part) */
    cfg_fmt_sprintf(ctx->err_buf, ctx->err_len,
                    "line %d, column %d: `%s': ",
                    line, column, cpBuf);
    free(cpBuf);

    /* remember parsing error: part II (parsing part) */
    n = strlen(ctx->err_buf);
    va_start(ap, fmt);
    cfg_fmt_vsprintf(ctx->err_buf+n, ctx->err_len-n, fmt, ap);
    va_end(ap);

    return;
}

/* internal cfg_syn_export structure */
typedef struct {
    cfg_t *cfg;
    cfg_buf_t *buf;
    int indent;
} export_t;

/* internal cfg_syn_export helper function: sprintf(3) style output formatting */
static void export_format(export_t *ctx, char *fmt, ...)
{
    int i;
    char *cp;
    char *cp2;
    va_list ap;
    char *str;

    va_start(ap, fmt);
    if ((str = cfg_fmt_vasprintf(fmt, ap)) == NULL)
        return;
    cp = str;
    while ((cp2 = strchr(cp, '\n')) != NULL) {
        cfg_buf_format(ctx->buf, "%.*s", cp2-cp+1, cp);
        for (i = 0; i < ctx->indent; i++)
            cfg_buf_format(ctx->buf, "    ");
        cp = cp2+1;
    }
    if (cp[0] != '\0')
        cfg_buf_format(ctx->buf, "%s", cp);
    free(str);
    va_end(ap);
    return;
}

/* internal cfg_syn_export helper function: indentation handling */
static void export_indent(export_t *ctx, signed int n)
{
    if (n > 0) {
        while (n > 0) {
            n--;
            ctx->indent++;
            cfg_buf_format(ctx->buf, "    ");
        }
    }
    else {
        while (n < 0 && ctx->indent > 0) {
            n++;
            ctx->indent--;
            cfg_buf_resize(ctx->buf, -4);
        }
    }
}

/* internal cfg_syn_export helper function: token output formatting */
static void export_token(export_t *ctx, const char *token)
{
    const char *cp;
    char *out;
    int plain;
    char c;

    plain = 1;
    for (cp = token; *cp != '\0'; cp++) {
        if (   !isprint((int)(*cp))
            || strchr(" \n\r\t\b\f;{}\\\"'", (int)(*cp)) != NULL) {
            plain = 0;
            break;
        }
    }
    if (plain)
        export_format(ctx, "%s", token);
    else {
        export_format(ctx, "\"");
        cp = token;
        while ((c = *cp++) != '\0') {
            out = NULL;
            switch (c) {
                case '\n': out = "\\n";  break;
                case '\r': out = "\\r";  break;
                case '\t': out = "\\t";  break;
                case '\b': out = "\\b";  break;
                case '\f': out = "\\f";  break;
                case '\\': out = "\\\\"; break;
                case '"' : out = "\\\""; break;
            }
            if (out != NULL)
                export_format(ctx, "%s", out);
            else {
                if (isprint((int)c))
                    export_format(ctx, "%c", c);
                else
                    export_format(ctx, "\\x%02x", c);
            }
        }
        export_format(ctx, "\"");
    }
    return;
}

/* internal cfg_syn_export helper function: recursive node processing */
static void export_node(export_t *ctx, cfg_node_t *node)
{
    cfg_node_type_t type;
    cfg_node_t *node2;
    cfg_rc_t rc;
    char *token;

    if ((rc = cfg_node_get(ctx->cfg, node, CFG_NODE_ATTR_TYPE, &type)) != CFG_OK)
        return;
    if (type == CFG_NODE_TYPE_SEQ) {
        /* node is a sequence */
        export_format(ctx, "{\n");
        export_indent(ctx, 1);
        cfg_node_get(ctx->cfg, node, CFG_NODE_ATTR_CHILD1, &node2);
        while (node2 != NULL) {
            export_node(ctx, node2); /* recursion */
            cfg_node_get(ctx->cfg, node2, CFG_NODE_ATTR_RBROTH, &node2);
        }
        export_indent(ctx, -1);
        export_format(ctx, "}");
    }
    else if (type == CFG_NODE_TYPE_DIR) {
        /* node is a directive */
        cfg_node_get(ctx->cfg, node, CFG_NODE_ATTR_CHILD1, &node2);
        while (node2 != NULL) {
            export_node(ctx, node2); /* recursion */
            cfg_node_get(ctx->cfg, node2, CFG_NODE_ATTR_RBROTH, &node2);
            if (node2 != NULL)
                export_format(ctx, " ");
        }
        cfg_node_get(ctx->cfg, node, CFG_NODE_ATTR_RBROTH, &node2);
        if (node2 != NULL)
            export_format(ctx, ";");
        export_format(ctx, "\n");
    }
    else if (type == CFG_NODE_TYPE_ARG) {
        /* node is a token */
        cfg_node_get(ctx->cfg, node, CFG_NODE_ATTR_TOKEN, &token);
        if (token != NULL)
            export_token(ctx, token);
        else
            export_format(ctx, "<?>");
    }
    return;
}

/* export configuration node tree into textual OSSP cfg syntax */
cfg_rc_t cfg_syn_export(
    cfg_t *cfg,
    cfg_node_t *node,
    char **output)
{
    cfg_buf_t *buf;
    cfg_rc_t rc;
    export_t ctx;
    cfg_node_t *root;

    if (node == NULL || output == NULL)
        return CFG_ERR_ARG;
    if ((rc = cfg_buf_create(&buf)) != CFG_OK)
        return rc;

    ctx.cfg    = cfg;
    ctx.buf    = buf;
    ctx.indent = 0;

    if ((rc = cfg_node_root(cfg, NULL, &root)) != CFG_OK)
        return rc;
    if (node == root) {
        /* if we dump the whole configuration, treat the first SEQ node special
           because of the implicit braces around it. So expand it manually instead
           of just calling once export_node(&ctx, node); */
        cfg_node_get(cfg, node, CFG_NODE_ATTR_CHILD1, &node);
        while (node != NULL) {
            export_node(&ctx, node);
            cfg_node_get(cfg, node, CFG_NODE_ATTR_RBROTH, &node);
        }
    }
    else {
        export_node(&ctx, node);
    }

    cfg_buf_content(buf, output, NULL, NULL);
    cfg_buf_destroy(buf);

    return CFG_OK;
}

/* internal cfg_syn_destroy helper function: recursive node destruction */
static cfg_rc_t cfg_syn_destroy_node(cfg_t *cfg, cfg_node_t *node)
{
    if (node == NULL)
        return CFG_ERR_ARG;
    if (node->child1 != NULL)
        cfg_syn_destroy_node(cfg, node->child1); /* recursion */
    if (node->rbroth != NULL)
        cfg_syn_destroy_node(cfg, node->rbroth); /* recursion */
    cfg_node_destroy(cfg, node);
    return CFG_OK;
}

/* destroy syntax node tree */
cfg_rc_t cfg_syn_destroy(cfg_t *cfg, cfg_node_t *node)
{
    if (node == NULL)
        return CFG_ERR_ARG;
    cfg_syn_destroy_node(cfg, node);
    return CFG_OK;
}