//! Displaying match data

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <macros.h>
#include <comp.h>
#include <display.h>

#define FLAGSET(f, flag) (( (f) & (flag) ) == (flag))
#define DFLAGSET(f, flagname) FLAGSET(f, DISPF_SHOW_ ## flagname)

#define CMP(x,cmp,y)  ( (x) cmp (y) ? (x) : (y) )
#define CMPv(x,cmp,y) ({ let _x = (x); let _y = (y); CMP(_x, cmp, _y); })
#define MIN(x, y) CMP((x), <, (y))
#define MINv(x, y) CMPv((x), <, (y))
#define MAX(x, y) CMP((x), >, (y))
#define MAXv(x, y) CMPv((x), >, (y))

// Returns number of bytes written to `dest`. Otherwise same as `strncpy()`.
static usize strncpy_n(char*pOUT dest, const char* restrict src, usize n)
{
	usize i;
	for(i=0;i<n;i++)
		if(! (*dest++ = *src++)) return i;
	dest[i] = 0;
	return i;
}

// Will not write past `dn` bytes of `dest`, will not read past `sn` bytes of `src`. Otherwise, same as `strncpy_n()`.
static usize s_strncpy_n(usize sn, usize dn; char dest[static pOUT dn], usize dn, const char src[static restrict sn], usize sn)
{
	usize i;
	usize n = MIN(sn,dn); 
	for(i=0;i<n;i++)
		if(! (*dest++ = *src++)) return i;
	if(i<dn) dest[i] = 0;
	return i;
}

// Will not write past `dn` bytes of `dest`, will not read past `sn` bytes of `src`. Otherwise, same as `strncat_n()`.
static inline usize s_strncat_n(usize sn, usize dn; char dest[static pOUT dn], usize dn, const char src[static restrict sn], usize sn)
{
	usize dl = MINv(strlen(dest), dn);
	return s_strncpy_n(dest + dl, dn - dl, src, sn);
}

// Returns number of bytes written to (dest+strlen(dest)). Otherwise same as `strncat()`.
static inline usize strncat_n(char*pOUT dest, const char* restrict src, usize n)
{
	usize dl = strlen(dest);
	return strncpy_n(dest+dl, src, n);
}

//TODO: This isn't working at all...
#ifdef _DEBUG_USE_UNSAFE_DISPLAY_FMT_ARGS
_dead
#endif
static usize _display_get_fmt_n(dispflags_t flags, bool matched, usize _n, char str[pOUT _n])
{
	register usize n = _n, fw=0;
	const char* fmts[] = { 
				DFLAGSET(flags, FAILURES) 
				? "failure: " 
				: "",  

				"match: ", 
				"%lu: ", 
				SLICE_FORMAT, 
				" (len %lu)", 
				(const char*)NULL,
	};
	usize   w = s_strncpy_n(str, n, fmts[!!matched], n); // SAFETY: Will never read past `fmts[x]` nul-terminator, so setting n as both dest and src length here is safe.
//TODO: Fix this... It isn't working...
#define ADDSTR(s) do { \
		debug_assert((s)); \
		w = MINv(s_strncat_n(str, n, (s), n), n); \
		/* Remove written from `n` */ \
		n -= w; \
		/* Check if we have written into the limit (if so, w will be equal to n above, since w is high-bounded to n by `MINv()` above. So if n is 0, we have hit the limit. */ \
		ifU(!n) { \
			/*XXX: Should this be `str[w-1]?` If this assert fails then yes it should. */ \
			debug_assert(w < _n); \
			str[w] = 0; \
			return fw + w; \
		} \
		/* Increase `str` pointer by written */ \
		str += w; \
		/* Increase return value by written. */ \
		fw += w; \
	} while(0)

	if(DFLAGSET(flags, NUMBER)) ADDSTR(fmts[2]);
	if(DFLAGSET(flags, SLICE)) ADDSTR(fmts[3]);
	if(DFLAGSET(flags, LENGTH)) ADDSTR(fmts[4]);
	ADDSTR("\n");
	TRACE("Output string written: %lu, (rlen %lu)", fw, n);
#undef ADDSTR
	return fw;
}


//XXX: This works, but seems inherantly unsafe. Rewrite to use the above `strn*_n()` functions for better length tracking.
#ifndef _DEBUG_USE_UNSAFE_DISPLAY_FMT_ARGS
_dead deprecated_message("this is unsafe, use `_display_get_fmt_n`") 
#endif
static usize _display_get_fmt0(dispflags_t flags, bool matched, usize _len, char str[pOUT _len])
{
	register usize len = _len;
	static const char* fmts[] = { "match: ", "%lu: ", SLICE_FORMAT, " (len %lu)", "failure: ", (const char*)NULL };
#define ADDSTR(s) do { debug_assert((s)); strncat(str, (s), len); w = strlen((s)); w = w > len ? len : w; ifU(len<=w) { str[len-1] = 0; return w; } len -= w; str += w; fw+=w; } while(0)
	usize fw;
	usize w = strlen(strncpy(str, matched ? fmts[0] 
					: DFLAGSET(flags, FAILURES) ? fmts[4]
					: "", len)); if(len<=w || w == 0) { str[len-1] = 0; return 0; } len -= w; str += w; fw = w;
	if(DFLAGSET(flags, NUMBER)) ADDSTR(fmts[1]);
	if(DFLAGSET(flags, SLICE)) ADDSTR(fmts[2]);
	if(DFLAGSET(flags, LENGTH)) ADDSTR(fmts[3]);
	ADDSTR("\n");
	TRACE("Output string written: %lu, (rlen %lu)", fw, len);
	return fw;
#undef ADDSTR
}

#ifdef _DEBUG_USE_UNSAFE_DISPLAY_FMT_ARGS
#define _display_get_fmt(...) _display_get_fmt0(__VA_ARGS__)
#else
#define _display_get_fmt(...) _display_get_fmt_n(__VA_ARGS__)
#endif

static void _display_normal(FILE* output, dispin_t*pIN input, dispflags_t flags)
{
	bool matched = input->matched;
	slice_t cslice = input->cslice;
	const void* base = input->base;
	usize i = input->index;

#ifdef _DEBUG_MANCALC_OFFSETS
	struct {
		usize start, end;
	} pos = {
		.start = AS(cslice.ptr - base, usize),
	};
	pos.end = pos.start + cslice.len;
#else
	let pos = slice_sted((slice_t[]){ SLICE(AS(cslice.ptr - base, usize), cslice.len)});
#endif
	INFO("Mapped region slice for %lu, pre-transform (at %p): " SLICE_FORMAT ", len: %lu", i+1, base, SLICE_FORMAT_ARGS(&cslice), cslice.len);

	// --- get format string from `flags` ---
	char fmt[200]; //TODO: Find the realistic max for this.
	usize fmtw = _display_get_fmt(flags, matched, sizeof(fmt)-1, fmt);
	assert(fmtw+1 < sizeof(fmt));
	fmt[fmtw+1] = 0;
	// ---
	TRACE("Format string get: `%s' (%lu)", fmt, fmtw);

	fprintf(output, fmt, i+1, pos.start, pos.end, pos.end-pos.start);
} 

void display_result(FILE* output, dispin_t input, dispkind_t how, dispflags_t flags)
{
	flags = flags ?: DISPLAY_FLAGS_DEFAULT;
	output = output ?: stdout;

	TRACE("Outputting as %d to %p with flags 0x%08lx", (int)how, output, (usize)flags);
	switch(how)
	{
		case DISPK_NORMAL:
			_display_normal(output, &input, flags);
			break;
		case DISPK_CSV:
		case DISPK_BINARY:
		case DISPK_INI:
			TODO("display kind %d is unimplemented", (int)how);
		default: COLD_EXPR(FATAL("unknown display kind: %d", (int)how));
	}
}