#include <ccan/str/str.h>
#include <ccan/talloc/talloc.h>
#include <ccan/grab_file/grab_file.h>
#include <ccan/str_talloc/str_talloc.h>
#include <ccan/read_write_all/read_write_all.h>
#include <ccan/compiler/compiler.h>
#include "tools.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <err.h>
#include <stdbool.h>
#include <unistd.h>
#include <errno.h>

static char ** PRINTF_FMT(2, 3)
lines_from_cmd(const void *ctx, const char *format, ...)
{
	va_list ap;
	char *cmd, *buffer;
	FILE *p;

	va_start(ap, format);
	cmd = talloc_vasprintf(ctx, format, ap);
	va_end(ap);

	p = popen(cmd, "r");
	if (!p)
		err(1, "Executing '%s'", cmd);

	buffer = grab_fd(ctx, fileno(p), NULL);
	if (!buffer)
		err(1, "Reading from '%s'", cmd);
	pclose(p);

	return strsplit(ctx, buffer, "\n");
}

/* Be careful about trying to compile over running programs (parallel make).
 * temp_file helps here. */
char *compile_info(const void *ctx, const char *dir)
{
	char *info_c_file, *info, *ccandir, *compiled, *output;
	size_t len;
	int fd;

	/* Copy it to a file with proper .c suffix. */
	info = grab_file(ctx, talloc_asprintf(ctx, "%s/_info", dir), &len);
	if (!info)
		return NULL;

	info_c_file = temp_file(ctx, ".c", "_info");
	fd = open(info_c_file, O_WRONLY|O_CREAT|O_EXCL, 0600);
	if (fd < 0)
		return NULL;
	if (!write_all(fd, info, len))
		return NULL;

	if (close(fd) != 0)
		return NULL;

	ccandir = talloc_dirname(ctx, dir);
	if (strrchr(ccandir, '/'))
		*strrchr(ccandir, '/') = '\0';

	compiled = temp_file(ctx, "", "info");
	if (compile_and_link(ctx, info_c_file, ccandir, "",
			     CCAN_COMPILER, CCAN_CFLAGS " -I.", "",
			     compiled, &output))
		return compiled;
	return NULL;
}

static char **get_one_deps(const void *ctx, const char *dir, const char *style,
			   char *(*get_info)(const void *ctx, const char *dir))
{
	char **deps, *cmd;
	char *infofile = get_info(ctx, dir);

	if (!infofile)
		return NULL;

	cmd = talloc_asprintf(ctx, "%s %s", infofile, style);
	deps = lines_from_cmd(cmd, "%s", cmd);
	if (!deps) {
		/* You must understand depends, maybe not testdepends. */
		if (streq(style, "depends"))
			err(1, "Could not run '%s'", cmd);
		deps = talloc(ctx, char *);
		deps[0] = NULL;
	}
	return deps;
}

/* Make copy of src, replacing "from" with "to". */
static char *replace(const void *ctx, const char *src,
		     const char *from, const char *to)
{
	char *ret = talloc_strdup(ctx, "");
	unsigned int rlen, len, add;

	rlen = len = 0;
	for (;;) {
		const char *next = strstr(src+len, from);
		if (!next)
			add = strlen(src+len) + 1;
		else
			add = next - (src+len);

		ret = talloc_realloc(ctx, ret, char, rlen + add + strlen(to)+1);
		memcpy(ret+rlen, src+len, add);
		if (!next)
			return ret;
		len += add;
		rlen += add;
		strcpy(ret+rlen, to);
		rlen += strlen(to);
		len += strlen(from);
	}
}

/* This is a terrible hack.  We scan for ccan/ strings. */
static char **get_one_safe_deps(const void *ctx,
				const char *dir,
				const char *style,
				char *(*unused)(const void *, const char *))
{
	char **deps, **lines, *raw, *fname;
	unsigned int i, n;
	bool correct_style = false;

	fname = talloc_asprintf(ctx, "%s/_info", dir);
	raw = grab_file(fname, fname, NULL);
	if (!raw)
		errx(1, "Could not open %s", fname);

	/* Replace \n by actual line breaks, and split it. */
	lines = strsplit(raw, replace(raw, raw, "\\n", "\n"), "\n");

	deps = talloc_array(ctx, char *, talloc_array_length(lines));

	for (n = i = 0; lines[i]; i++) {
		char *str;
		unsigned int len;

		/* Ignore lines starting with # (e.g. #include) */
		if (lines[i][0] == '#')
			continue;

		if (strstr(lines[i], "\"testdepends\""))
			correct_style = streq(style, "testdepends");
		else if (strstr(lines[i], "\"depends\""))
			correct_style = streq(style, "depends");

		if (!correct_style)
			continue;

		/* Start of line, or after ". */
		if (strstarts(lines[i], "ccan/"))
			str = lines[i];
		else {
			str = strstr(lines[i], "\"ccan/");
			if (!str)
				continue;
			str++;
		}
		
		len = strspn(str, "/abcdefghijklmnopqrstuvxwyz12345678980_");
		if (len == 5)
			continue;
		deps[n++] = talloc_strndup(deps, str, len);
	}
	deps[n] = NULL;
	talloc_free(fname);

	/* Make sure talloc_array_length() works */
	return talloc_realloc(NULL, deps, char *, n + 1);
}

static bool have_dep(char **deps, const char *dep)
{
	unsigned int i;

	for (i = 0; deps[i]; i++)
		if (streq(deps[i], dep))
			return true;
	return false;
}



/* Gets all the dependencies, recursively. */
static char **
get_all_deps(const void *ctx, const char *dir, const char *style,
	     char *(*get_info)(const void *ctx, const char *dir),
	     char **(*get_one)(const void *, const char *, const char *,
			       char *(*get_info)(const void *, const char *)))
{
	char **deps;
	unsigned int i;

	deps = get_one(ctx, dir, style, get_info);
	for (i = 0; i < talloc_array_length(deps)-1; i++) {
		char **newdeps;
		unsigned int j;
		char *subdir;

		if (!strstarts(deps[i], "ccan/"))
			continue;

		subdir = talloc_asprintf(ctx, "%s/%s",
					 talloc_dirname(ctx, dir),
					 deps[i] + strlen("ccan/"));
		newdeps = get_one(ctx, subdir, "depends", get_info);

		/* Should be short, so brute-force out dups. */
		for (j = 0; j < talloc_array_length(newdeps)-1; j++) {
			unsigned int num;

			if (have_dep(deps, newdeps[j]))
				continue;

			num = talloc_array_length(deps)-1;
			deps = talloc_realloc(NULL, deps, char *, num + 2);
			deps[num] = newdeps[j];
			deps[num+1] = NULL;
		}
	}
	return deps;
}

/* Can return NULL: _info may not support 'libs'. */
static char **get_one_libs(const void *ctx, const char *dir,
			   char *(*get_info)(const void *ctx, const char *dir))
{
	char *cmd, **lines;

	cmd = talloc_asprintf(ctx, "%s libs", get_info(ctx, dir));
	lines = lines_from_cmd(cmd, "%s", cmd);
	/* Strip final NULL. */
	if (lines)
		lines = talloc_realloc(NULL, lines, char *,
				       talloc_array_length(lines)-1);
	return lines;
}

/* O(n^2) but n is small. */
static char **add_deps(char **deps1, char **deps2)
{
	unsigned int i, len;

	len = talloc_array_length(deps1);

	for (i = 0; deps2[i]; i++) {
		if (have_dep(deps1, deps2[i]))
			continue;
		deps1 = talloc_realloc(NULL, deps1, char *, len + 1);
		deps1[len-1] = talloc_steal(deps1, deps2[i]);
		deps1[len++] = NULL;
	}
	return deps1;
}

char **get_libs(const void *ctx, const char *dir, const char *style,
		char *(*get_info)(const void *ctx, const char *dir))
{
	char **deps, **libs;
	unsigned int i, len;

	libs = get_one_libs(ctx, dir, get_info);
	len = talloc_array_length(libs);

	if (style) {
		deps = get_deps(ctx, dir, style, true, get_info);
		if (streq(style, "testdepends"))
			deps = add_deps(deps,
					get_deps(ctx, dir, "depends", true,
						 get_info));

		for (i = 0; deps[i]; i++) {
			char **newlibs, *subdir;
			size_t newlen;

			if (!strstarts(deps[i], "ccan/"))
				continue;

			subdir = talloc_asprintf(ctx, "%s/%s",
						 talloc_dirname(ctx, dir),
						 deps[i] + strlen("ccan/"));

			newlibs = get_one_libs(ctx, subdir, get_info);
			newlen = talloc_array_length(newlibs);
			libs = talloc_realloc(ctx, libs, char *, len + newlen);
			memcpy(&libs[len], newlibs,
			       sizeof(newlibs[0])*newlen);
			len += newlen;
		}
	}

	/* Append NULL entry. */
	libs = talloc_realloc(ctx, libs, char *, len + 1);
	libs[len] = NULL;
	return libs;
}

/* FIXME: This is O(n^2), which is dumb. */
static char **uniquify_deps(char **deps)
{
	unsigned int i, j, num;

	if (!deps)
		return NULL;

	num = talloc_array_length(deps) - 1;
	for (i = 0; i < num; i++) {
		for (j = i + 1; j < num; j++) {
			if (streq(deps[i], deps[j])) {
				memmove(&deps[j], &deps[j+1],
					(num - j - 1) * sizeof(char *));
				num--;
			}
		}
	}
	deps[num] = NULL;
	/* Make sure talloc_array_length() works */
	return talloc_realloc(NULL, deps, char *, num + 1);
}

char **get_deps(const void *ctx, const char *dir, const char *style,
		bool recurse,
		char *(*get_info)(const void *ctx, const char *dir))
{
	char **ret;

	if (!recurse) {
		ret = get_one_deps(ctx, dir, style, get_info);
	} else
		ret = get_all_deps(ctx, dir, style, get_info, get_one_deps);

	return uniquify_deps(ret);
}

char **get_safe_ccan_deps(const void *ctx, const char *dir, const char *style,
			  bool recurse)
{
	char **ret;
	if (!recurse) {
		ret = get_one_safe_deps(ctx, dir, style, NULL);
	} else {
		ret = get_all_deps(ctx, dir, style, NULL, get_one_safe_deps);
	}
	return uniquify_deps(ret);
}