#include "config.h"

#include <stdlib.h>
#include <stdio.h>
#include <wchar.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <errno.h>
#include <libgen.h>

#include "fallback.h"
#include "util.h"

#include "common.h"
#include "env.h"
#include "wutil.h"
#include "path.h"
#include "expand.h"

/**
   Unexpected error in path_get_path()
*/
#define MISSING_COMMAND_ERR_MSG _( L"Error while searching for command '%ls'" )

static bool path_get_path_core(const wcstring &cmd, wcstring *out_path, const env_var_t &bin_path_var)
{
	int err = ENOENT;
	
	debug( 3, L"path_get_path( '%ls' )", cmd.c_str() );
    
    /* If the command has a slash, it must be a full path */
	if (cmd.find(L'/') != wcstring::npos)
	{
		if( waccess( cmd, X_OK )==0 )
		{
			struct stat buff;
			if(wstat( cmd, &buff ))
			{
				return false;
			}
			
			if( S_ISREG(buff.st_mode) )
            {
				if (out_path)
                    out_path->assign(cmd);
                return true;
            }
			else
			{
				errno = EACCES;
				return false;
			}
		}
		else
		{
			struct stat buff;
			wstat( cmd, &buff );
			return false;
		}
		
	}
	else
	{
        wcstring bin_path;
		if (! bin_path_var.missing())
        {
            bin_path = bin_path_var;
        }
        else
		{
			if (contains( PREFIX L"/bin", L"/bin", L"/usr/bin" ))
			{
				bin_path = L"/bin" ARRAY_SEP_STR L"/usr/bin";
			}
			else
			{
				bin_path = L"/bin" ARRAY_SEP_STR L"/usr/bin" ARRAY_SEP_STR PREFIX L"/bin";
			}
		}
		
        wcstring nxt_path;
        wcstokenizer tokenizer(bin_path, ARRAY_SEP_STR);
		while (tokenizer.next(nxt_path))
		{
            if (nxt_path.empty())
                continue;
            append_path_component(nxt_path, cmd);
			if( waccess( nxt_path, X_OK )==0 )
			{
				struct stat buff;
				if( wstat( nxt_path, &buff )==-1 )
				{
					if( errno != EACCES )
					{
						wperror( L"stat" );
					}
					continue;
				}
				if( S_ISREG(buff.st_mode) )
				{
                    if (out_path)
                        out_path->swap(nxt_path);
					return true;
				}
				err = EACCES;
				
			}
			else
			{
				switch( errno )
				{
					case ENOENT:
					case ENAMETOOLONG:
					case EACCES:
					case ENOTDIR:
						break;
					default:
					{
						debug( 1,
                              MISSING_COMMAND_ERR_MSG,
                              nxt_path.c_str() );
						wperror( L"access" );
					}
				}
			}
		}
	}
    
	errno = err;
	return false;
}

bool path_get_path(const wcstring &cmd, wcstring *out_path, const env_vars_snapshot_t &vars)
{
    return path_get_path_core(cmd, out_path, vars.get(L"PATH"));
}

bool path_get_path(const wcstring &cmd, wcstring *out_path)
{
    return path_get_path_core(cmd, out_path, env_get_string(L"PATH"));
}

bool path_get_cdpath_string(const wcstring &dir_str, wcstring &result, const env_var_t &cdpath)
{
	wchar_t *res = 0;
	int err = ENOENT;
    bool success = false;
    
    const wchar_t *const dir = dir_str.c_str();
	if( dir[0] == L'/'|| (wcsncmp( dir, L"./", 2 )==0) )
	{
		struct stat buf;
		if( wstat( dir, &buf ) == 0 )
		{
			if( S_ISDIR(buf.st_mode) )
			{
				result = dir_str;
                success = true;
			}
			else
			{
				err = ENOTDIR;
			}
            
		}
	}
	else
	{
        
        wcstring path = L".";
                
        // Respect CDPATH
        env_var_t cdpath = env_get_string(L"CDPATH");
        if (! cdpath.missing_or_empty()) {
            path = cdpath.c_str();
        }
        
        wcstokenizer tokenizer(path, ARRAY_SEP_STR);
        wcstring next_path;
        while (tokenizer.next(next_path))
        {
            expand_tilde(next_path);
            if (next_path.size() == 0) continue;
            
            wcstring whole_path = next_path;
            append_path_component(whole_path, dir);
            
			struct stat buf;
			if( wstat( whole_path, &buf ) == 0 )
			{
				if( S_ISDIR(buf.st_mode) )
				{
                    result = whole_path;
                    success = true;
					break;
				}
				else
				{
					err = ENOTDIR;
				}
			}
			else
			{
				if( lwstat( whole_path, &buf ) == 0 )
				{
					err = EROTTEN;
				}
			}
        }
    }
		
    
	if( !success )
	{
		errno = err;
	}
    
	return res;
}

bool path_get_cdpath(const wcstring &dir, wcstring *out, const wchar_t *wd, const env_vars_snapshot_t &env_vars)
{
	int err = ENOENT;
	if (dir.empty())
		return false;
        
    if (wd)
    {
        size_t len = wcslen(wd);
        assert(wd[len - 1] == L'/');
    }
    
    wcstring_list_t paths;
    if (dir.at(0) == L'/') {
        /* Absolute path */
        paths.push_back(dir);
    } else if (string_prefixes_string(L"./", dir) ||
               string_prefixes_string(L"../", dir) ||
               dir == L"." || dir == L"..") {
        /* Path is relative to the working directory */
        wcstring path;
        if (wd)
            path.append(wd);
        path.append(dir);
        paths.push_back(path);
    } else {
        // Respect CDPATH
        env_var_t path = env_vars.get(L"CDPATH");
        if (path.missing_or_empty())
            path = L"."; //We'll change this to the wd if we have one

        wcstring nxt_path;
        wcstokenizer tokenizer(path, ARRAY_SEP_STR);
        while (tokenizer.next(nxt_path))
        {
        
            if (nxt_path == L"." && wd != NULL) {
                // nxt_path is just '.', and we have a working directory, so use the wd instead
                // TODO: if nxt_path starts with ./ we need to replace the . with the wd
                nxt_path = wd;
            }
            expand_tilde(nxt_path);

//			debug( 2, L"woot %ls\n", expanded_path.c_str() );

            if (nxt_path.empty())
                continue;
            
            wcstring whole_path = nxt_path;
            append_path_component(whole_path, dir);
            paths.push_back(whole_path);
        }
    }
    
    bool success = false;
    for (wcstring_list_t::const_iterator iter = paths.begin(); iter != paths.end(); ++iter) {
		struct stat buf;
        const wcstring &dir = *iter;
		if( wstat( dir, &buf ) == 0 )
		{
			if( S_ISDIR(buf.st_mode) )
			{
                success = true;
                if (out)
                    out->assign(dir);
                break;
			}
			else
			{
				err = ENOTDIR;
			}
		}
    }
     
    if (! success)
		errno = err;
    return success;
}

bool path_can_be_implicit_cd(const wcstring &path, wcstring *out_path, const wchar_t *wd, const env_vars_snapshot_t &vars)
{
    wcstring exp_path = path;
    expand_tilde(exp_path);
    
    bool result = false;
    if (string_prefixes_string(L"/", exp_path) ||
        string_prefixes_string(L"./", exp_path) ||
        string_prefixes_string(L"../", exp_path) ||
        exp_path == L"..")
    {
        /* These paths can be implicit cd, so see if you cd to the path. Note that a single period cannot (that's used for sourcing files anyways) */
        result = path_get_cdpath(exp_path, out_path, wd, vars);
    }
    return result;
}

bool path_get_config(wcstring &path)
{
	int done = 0;
	wcstring res;
	
	const env_var_t xdg_dir  = env_get_string( L"XDG_CONFIG_HOME" );
	if( ! xdg_dir.missing() )
	{
		res = xdg_dir + L"/fish";
		if( !create_directory( res ) )
		{
			done = 1;
		}
	}
	else
	{		
		const env_var_t home = env_get_string( L"HOME" );
		if( ! home.missing() )
		{
			res = home + L"/.config/fish";
			if( !create_directory( res ) )
			{
				done = 1;
			}
		}
	}
	
	if( done )
	{
        path = res;
        return true;
	}
	else
	{
		debug( 0, _(L"Unable to create a configuration directory for fish. Your personal settings will not be saved. Please set the $XDG_CONFIG_HOME variable to a directory where the current user has write access." ));
		return false;
	}	

}

static void replace_all(wcstring &str, const wchar_t *needle, const wchar_t *replacement)
{
    size_t needle_len = wcslen(needle);
    size_t offset = 0;
    while((offset = str.find(needle, offset)) != wcstring::npos)
    {
        str.replace(offset, needle_len, replacement);
        offset += needle_len;
    }
}

void path_make_canonical( wcstring &path )
{

    /* Remove double slashes */
    size_t size;
    do {
        size = path.size();
        replace_all(path, L"//", L"/");
    } while (path.size() != size);
    
    /* Remove trailing slashes, except don't remove the first one */
    while (size-- > 1) {
        if (path.at(size) != L'/')
            break;
    }
    /* Now size is either -1 (if the entire string was slashes) or is the index of the last non-slash character. Either way this will set it to the correct size. */
    path.resize(size+1);
}

bool path_is_valid(const wcstring &path, const wcstring &working_directory)
{
    bool path_is_valid;
    /* Some special paths are always valid */
    if (path.empty()) {
        path_is_valid = false;
    } else if (path == L"." || path == L"./") {
        path_is_valid = true;
    } else if (path == L".." || path == L"../") {
        path_is_valid = (! working_directory.empty() && working_directory != L"/");
    } else if (path.at(0) != '/') {
        /* Prepend the working directory. Note that we know path is not empty here. */
        wcstring tmp = working_directory;
        tmp.append(path);
        path_is_valid = (0 == waccess(tmp, F_OK));
    } else {
        /* Simple check */
        path_is_valid = (0 == waccess(path, F_OK));
    }
    return path_is_valid;
}

bool paths_are_same_file(const wcstring &path1, const wcstring &path2) {
    if (path1 == path2)
        return true;
        
    struct stat s1, s2;
    if (wstat(path1, &s1) == 0 && wstat(path2, &s2) == 0) {
        return s1.st_ino == s2.st_ino && s1.st_dev == s2.st_dev;
    } else {
        return false;
    }
}

wcstring get_working_directory(void) {
    wcstring wd = L"./";
    wchar_t dir_path[4096];
    const wchar_t *cwd = wgetcwd( dir_path, 4096 );
    if (cwd) {
        wd = cwd;
        /* Make sure the working directory ends with a slash */
        if (! wd.empty() && wd.at(wd.size() - 1) != L'/')
            wd.push_back(L'/');
    }
    return wd;
}