/* ====================================================================
 * Copyright 1999 Web Juice, LLC. All rights reserved.
 *
 * context.c
 *
 * Functions for manipulating the context structure in the template
 * library.
 *
 * ==================================================================== */
#include <stdlib.h>
#include <context.h>
#include <varlist.h>
#include <nclist.h>
/* ====================================================================
 * NAME:          context_init
 *
 * DESCRIPTION:   Initializes and returns a pointer to a new context
 *                structure.
 *
 * RETURN VALUES: Returns NULL if the memory allocation fails; otherwise
 *                returns a pointer to a varlist structure.
 *
 * BUGS:          Hopefully none.
 * ==================================================================== */
context_p
context_init(void)
{
    context_p ctx;
    ctx = (context_p)calloc(1, sizeof(context));
    if (ctx == NULL)
    {
        return NULL;
    }
    ctx->variables = varlist_init();
    if (ctx->variables == NULL)
    {
        free(ctx);
        return NULL;
    }
    ctx->named_child_contexts = nclist_init();
    if (ctx->named_child_contexts == NULL)
    {
        varlist_destroy(ctx->variables);
        free(ctx);
        return NULL;
    }
    ctx->parent_context  = NULL;
    ctx->next_context    = NULL;
    ctx->output_contents = 1;
    ctx->anonymous       = 0;
    return(ctx);
}
/* ====================================================================
 * NAME:          context_destroy
 *
 * DESCRIPTION:   Frees up all memory associated with a context.
 *
 * RETURN VALUES: None.
 *
 * BUGS:          Because a free()d pointer still *looks* valid, it is
 *                difficult to protect against the problems that arise
 *                if the user calls this function too early.
 * ==================================================================== */
void
context_destroy(context_p ctx)
{
    context_p next;
    if (ctx == NULL)
    {
        return;
    }
    next = ctx->next_context;
    if (ctx->named_child_contexts != NULL)
    {
        nclist_destroy(ctx->named_child_contexts);
    }
    if (ctx->variables != NULL)
    {
        varlist_destroy(ctx->variables);
    }
    ctx->named_child_contexts = NULL;
    ctx->variables            = NULL;
    ctx->next_context         = NULL;
    ctx->parent_context       = NULL;
    free(ctx);
    context_destroy(next);
}
/* ====================================================================
 * NAME:          context_get_value
 *
 * DESCRIPTION:   Returns the value of the variable stored under the given
 *                name in the current context or any parents' variable list.
 *
 * RETURN VALUES: This function will return NULL if there are any problems
 *                or if there is no value.  It returns a string containing
 *                the value on success.
 *
 * BUGS:          Hopefully none.
 * ==================================================================== */
char *
context_get_value(context_p ctx, char *name)
{
    char *result;
    if (ctx == NULL)
    {
        return NULL;
    }
    result = varlist_get_value(ctx->variables, name);
    if (result != NULL)
    {
        return(result);
    }
    if (ctx->parent_context == NULL)
    {
        return NULL;
    }
    return(context_get_value(ctx->parent_context, name));
}
/* ====================================================================
 * NAME:          context_set_value
 *
 * DESCRIPTION:   Set a variable in the context's variable list.
 *
 * RETURN VALUES: Returns 0 if there's any trouble.  Returns 1 if the
 *                variable was successfully set.
 *
 * BUGS:          Hopefully none.
 * ==================================================================== */
int
context_set_value(context_p ctx, char *name, char *value)
{
    if (ctx == NULL)
    {
        return 0;
    }
    return(varlist_set_value(ctx->variables, name, value));
}
/* ====================================================================
 * NAME:          context_get_anonymous_child
 *
 * DESCRIPTION:   Creates and returns an unnamed context with the parent
 *                set to the current context (i.e. a new context within
 *                the scope of the current context).
 *
 * RETURN VALUES: Returns NULL if there's a problem; returns a pointer to
 *                the new context otherwise.
 *
 * BUGS:          Hopefully none.
 * ==================================================================== */
context_p
context_get_anonymous_child(context_p ctx)
{
    context_p anonymous_ctx;
    if (ctx == NULL)
    {
        return NULL;
    }
    anonymous_ctx = context_init();
    if (anonymous_ctx == NULL)
    {
        return NULL;
    }
    anonymous_ctx->parent_context = ctx;
    anonymous_ctx->anonymous      = 1;
    return(anonymous_ctx);
}
/* ====================================================================
 * NAME:          context_get_named_child
 *
 * DESCRIPTION:   This function returns a named context within the scope
 *                of the current context, if it exists.
 *
 * RETURN VALUES: Returns NULL if there is any problem, or if the context
 *                doesn't exist; else returns a pointer to the context.
 *
 * BUGS:          Hopefully none.
 * ==================================================================== */
context_p
context_get_named_child(context_p ctx, char *name)
{
    context_p result;
    if (ctx == NULL)
    { 
        return NULL;
    }
    result = nclist_get_context(ctx->named_child_contexts, name);
    if (result != NULL)
    {
        return(result);
    }
    if (ctx->parent_context == NULL)
    {
        return NULL;
    }
    return(context_get_named_child(ctx->parent_context, name));
}
/* ====================================================================
 * NAME:          context_set_named_child
 *
 * DESCRIPTION:   This function creates a new named context within the
 *                scope of the current context.
 *
 * RETURN VALUES: Returns 0 if there is any trouble; returns 1 on success.
 *
 * BUGS:          Hopefully none.
 * ==================================================================== */
int
context_set_named_child(context_p ctx, char *name)
{
    context_p named_ctx;
    if (ctx == NULL)
    {
        return 0;
    }
    if (! nclist_new_context(ctx->named_child_contexts, name))
    {
        return 0;
    }
    named_ctx = context_get_named_child(ctx, name);
    if (named_ctx == NULL)
    {
        return 0;
    }
    named_ctx->parent_context = ctx;
    return 1;
}
/* ====================================================================
 * NAME:          context_add_peer
 *
 * DESCRIPTION:   This function adds a peer context (a.k.a. loop iteration)
 *                to the context passed in, and initializes it.
 *
 * RETURN VALUES: Returns NULL if there is any trouble; returns a pointer to
 *                the new peer context otherwise.
 *
 * BUGS:          Hopefully none.
 * ==================================================================== */
context_p
context_add_peer(context_p ctx)
{
    context_p peer_ctx;
    context_p current = ctx;
    if (ctx == NULL)
    {
        return NULL;
    }
    peer_ctx = context_init();
    if (peer_ctx == NULL)
    {
        return NULL;
    }
    peer_ctx->parent_context = ctx->parent_context;
    while (current->next_context !=  NULL)
    {
        current = current->next_context;
    }
    current->next_context = peer_ctx;
    return(peer_ctx);
}
/* ====================================================================
 * NAME:          context_output_contents
 *
 * DESCRIPTION:   This function adds a peer context (a.k.a. loop iteration)
 *
 * RETURN VALUES: None.
 *
 * BUGS:          Hopefully none.
 * ==================================================================== */
void
context_output_contents(context_p ctx, char output_contents)
{
    if (ctx == NULL)
    {
        return;
    }
    ctx->output_contents = output_contents;
    return;
}