/*
 * mkdio -- markdown front end input functions
 *
 * Copyright (C) 2007 David L Parsons.
 * The redistribution terms are provided in the COPYRIGHT file that must
 * be distributed with this source code.
 */
#include "config.h"
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

#include "cstring.h"
#include "markdown.h"
#include "amalloc.h"

typedef ANCHOR(Line) LineAnchor;


/* create a new blank Document
 */
Document*
__mkd_new_Document()
{
    Document *ret = calloc(sizeof(Document), 1);

    if ( ret ) {
	if ( ret->ctx = calloc(sizeof(MMIOT), 1) ) {
	    ret->magic = VALID_DOCUMENT;
	    return ret;
	}
	free(ret);
    }
    return 0;
}


/* add a line to the markdown input chain, expanding tabs and
 * noting the presence of special characters as we go.
 */
void
__mkd_enqueue(Document* a, Cstring *line)
{
    Line *p = calloc(sizeof *p, 1);
    unsigned char c;
    int xp = 0;
    int           size = S(*line);
    unsigned char *str = (unsigned char*)T(*line);

    CREATE(p->text);
    ATTACH(a->content, p);

    while ( size-- ) {
	if ( (c = *str++) == '\t' ) {
	    /* expand tabs into ->tabstop spaces.  We use ->tabstop
	     * because the ENTIRE FREAKING COMPUTER WORLD uses editors
	     * that don't do ^T/^D, but instead use tabs for indentation,
	     * and, of course, set their tabs down to 4 spaces 
	     */
	    do {
		EXPAND(p->text) = ' ';
	    } while ( ++xp % a->tabstop );
	}
	else if ( c >= ' ' ) {
	    if ( c == '|' )
		p->flags |= PIPECHAR;
	    EXPAND(p->text) = c;
	    ++xp;
	}
    }
    EXPAND(p->text) = 0;
    S(p->text)--;
    p->dle = mkd_firstnonblank(p);
}


/* trim leading characters from a line, then adjust the dle.
 */
void
__mkd_trim_line(Line *p, int clip)
{
    if ( clip >= S(p->text) ) {
	S(p->text) = p->dle = 0;
	T(p->text)[0] = 0;
    }
    else if ( clip > 0 ) {
	CLIP(p->text, 0, clip);
	p->dle = mkd_firstnonblank(p);
    }
}


/* build a Document from any old input.
 */
typedef int (*getc_func)(void*);

Document *
populate(getc_func getc, void* ctx, mkd_flag_t flags)
{
    Cstring line;
    Document *a = __mkd_new_Document();
    int c;
    int pandoc = 0;

    if ( !a ) return 0;

    a->tabstop = is_flag_set(flags, MKD_TABSTOP) ? 4 : TABSTOP;

    CREATE(line);

    while ( (c = (*getc)(ctx)) != EOF ) {
	if ( c == '\n' ) {
	    if ( pandoc != EOF && pandoc < 3 ) {
		if ( S(line) && (T(line)[0] == '%') )
		    pandoc++;
		else
		    pandoc = EOF;
	    }
	    __mkd_enqueue(a, &line);
	    S(line) = 0;
	}
	else if ( isprint(c) || isspace(c) || (c & 0x80) )
	    EXPAND(line) = c;
    }

    if ( S(line) )
	__mkd_enqueue(a, &line);

    DELETE(line);

    if ( (pandoc == 3) && !(is_flag_set(flags, MKD_NOHEADER) || is_flag_set(flags, MKD_STRICT)) ) {
	/* the first three lines started with %, so we have a header.
	 * clip the first three lines out of content and hang them
	 * off header.
	 */
	Line *headers = T(a->content);

	a->title = headers;             __mkd_trim_line(a->title, 1);
	a->author= headers->next;       __mkd_trim_line(a->author, 1);
	a->date  = headers->next->next; __mkd_trim_line(a->date, 1);

	T(a->content) = headers->next->next->next;
    }

    return a;
}


/* convert a file into a linked list
 */
Document *
mkd_in(FILE *f, mkd_flag_t flags)
{
    return populate((getc_func)fgetc, f, flags & INPUT_MASK);
}


/* return a single character out of a buffer
 */
int
__mkd_io_strget(struct string_stream *in)
{
    if ( !in->size ) return EOF;

    --(in->size);

    return *(in->data)++;
}


/* convert a block of text into a linked list
 */
Document *
mkd_string(const char *buf, int len, mkd_flag_t flags)
{
    struct string_stream about;

    about.data = buf;
    about.size = len;

    return populate((getc_func)__mkd_io_strget, &about, flags & INPUT_MASK);
}


/* write the html to a file (xmlified if necessary)
 */
int
mkd_generatehtml(Document *p, FILE *output)
{
    char *doc;
    int szdoc;

    DO_OR_DIE( szdoc = mkd_document(p,&doc) );
    if ( is_flag_set(p->ctx->flags, MKD_CDATA) )
	DO_OR_DIE( mkd_generatexml(doc, szdoc, output) );
    else if ( fwrite(doc, szdoc, 1, output) != 1 )
	return EOF;
    DO_OR_DIE( putc('\n', output) );
    return 0;
}


/* convert some markdown text to html
 */
int
markdown(Document *document, FILE *out, mkd_flag_t flags)
{
    if ( mkd_compile(document, flags) ) {
	mkd_generatehtml(document, out);
	mkd_cleanup(document);
	return 0;
    }
    return -1;
}


/* anchor_format a string, returning the formatted string in malloc()ed space
 * MKD_URLENCODEDANCHOR is now perverted to being a html5 anchor
 *
 * !labelformat:  print all characters
 * labelformat && h4anchor: prefix nonalpha label with L,
 *                          expand all nonalnum, _, ':', '.' to hex
 *                          except space which maps to -
 * labelformat && !h4anchor:expand space to -, other isspace() & '%' to hex
 */
static char *
mkd_anchor_format(char *s, int len, int labelformat, mkd_flag_t flags)
{
    char *res;
    unsigned char c;
    int i, needed, out = 0;
    int h4anchor = !is_flag_set(flags, MKD_URLENCODEDANCHOR);
    static const unsigned char hexchars[] = "0123456789abcdef";

    needed = labelformat ? (4*len) : len;

    if ( (res = malloc(needed)) == NULL )
	return NULL;

    if ( h4anchor && labelformat && !isalpha(s[0]) )
	res[out++] = 'L';
	
    
    for ( i=0; i < len ; i++ ) {
	c = s[i];
	if ( labelformat ) {
	    if ( h4anchor
		    ? (isalnum(c) || (c == '_') || (c == ':') || (c == '.' ) )
		    : !(isspace(c) || c == '%') )
		res[out++] = c;
	    else if ( c == ' ' )
		res[out++] = '-';
	    else {
		    res[out++] = h4anchor ? '-' : '%';
		    res[out++] = hexchars[c >> 4 & 0xf];
		    res[out++] = hexchars[c      & 0xf];
		    if ( h4anchor )
			res[out++] = '-';
	    }
	}
	else
	    res[out++] = c;
    }
    
    res[out++] = 0;
    return res;
} /* mkd_anchor_format */


/* write out a Cstring, mangled into a form suitable for `<a href=` or `<a id=`
 */
void
mkd_string_to_anchor(char *s, int len, mkd_sta_function_t outchar,
				       void *out, int labelformat,
				       MMIOT *f)
{
    char *res;
    char *line;
    int size;

    int i;

    size = mkd_line(s, len, &line, IS_LABEL);

    if ( !line )
	return;

    if ( f->cb->e_anchor )
	res = (*(f->cb->e_anchor))(line, size, f->cb->e_data);
    else
	res = mkd_anchor_format(line, size, labelformat, f->flags);

    free(line);

    if ( !res )
	return;

    for ( i=0; res[i]; i++ )
	(*outchar)(res[i], out);

    if ( f->cb->e_anchor ) {
	if ( f->cb->e_free )
	    (*(f->cb->e_free))(res, f->cb->e_data);
    }
    else 
	free(res);
}


/*  ___mkd_reparse() a line
 */
static void
mkd_parse_line(char *bfr, int size, MMIOT *f, mkd_flag_t flags)
{
    ___mkd_initmmiot(f, 0);
    f->flags = flags & USER_FLAGS;
    ___mkd_reparse(bfr, size, 0, f, 0);
    ___mkd_emblock(f);
}


/* ___mkd_reparse() a line, returning it in malloc()ed memory
 */
int
mkd_line(char *bfr, int size, char **res, mkd_flag_t flags)
{
    MMIOT f;
    int len;
    
    mkd_parse_line(bfr, size, &f, flags);

    if ( len = S(f.out) ) {
	EXPAND(f.out) = 0;
	/* strdup() doesn't use amalloc(), so in an amalloc()ed
	 * build this copies the string safely out of our memory
	 * paranoia arena.  In a non-amalloc world, it's a spurious
	 * memory allocation, but it avoids unintentional hilarity
	 * with amalloc()
	 */
	*res = strdup(T(f.out));
    }
    else {
	 *res = 0;
	 len = EOF;
     }
    ___mkd_freemmiot(&f, 0);
    return len;
}


/* ___mkd_reparse() a line, writing it to a FILE
 */
int
mkd_generateline(char *bfr, int size, FILE *output, mkd_flag_t flags)
{
    MMIOT f;
    int status;

    mkd_parse_line(bfr, size, &f, flags);
    if ( is_flag_set(flags, MKD_CDATA) )
	status = mkd_generatexml(T(f.out), S(f.out), output) != EOF;
    else
	status = fwrite(T(f.out), S(f.out), 1, output) == S(f.out);

    ___mkd_freemmiot(&f, 0);
    return status ? 0 : EOF;
}


/* set the url display callback
 */
void
mkd_e_url(Document *f, mkd_callback_t edit)
{
    if ( f ) {
	if ( f->cb.e_url != edit )
	    f->dirty = 1;
	f->cb.e_url = edit;
    }
}


/* set the url options callback
 */
void
mkd_e_flags(Document *f, mkd_callback_t edit)
{
    if ( f ) {
	if ( f->cb.e_flags != edit )
	    f->dirty = 1;
	f->cb.e_flags = edit;
    }
}


/* set the anchor formatter
 */
void
mkd_e_anchor(Document *f, mkd_callback_t format)
{
    if ( f ) {
	if ( f->cb.e_anchor != format )
	    f->dirty = 1;
	f->cb.e_anchor = format;
    }
}


/* set the url display/options deallocator
 */
void
mkd_e_free(Document *f, mkd_free_t dealloc)
{
    if ( f ) {
	if ( f->cb.e_free != dealloc )
	    f->dirty = 1;
	f->cb.e_free = dealloc;
    }
}


/* set the url display/options context data field
 */
void
mkd_e_data(Document *f, void *data)
{
    if ( f ) {
	if ( f->cb.e_data != data )
	    f->dirty = 1;
	f->cb.e_data = data;
    }
}


/* set the code block display callback
 */
void
mkd_e_code_format(Document *f, mkd_callback_t codefmt)
{
    if ( f && (f->cb.e_codefmt != codefmt) ) {
	f->dirty = 1;
	f->cb.e_codefmt = codefmt;
    }
}


/* set the href prefix for markdown extra style footnotes
 */
void
mkd_ref_prefix(Document *f, char *data)
{
    if ( f ) {
	if ( f->ref_prefix != data )
	    f->dirty = 1;
	f->ref_prefix = data;
    }
}
