// Emacs style mode select   -*- C++ -*- 
//-----------------------------------------------------------------------------
//
// Copyright(C) 2006 Simon Howard
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
// 02111-1307, USA.
//
// DESCRIPTION:
//     Search for and locate an IWAD file, and initialise according
//     to the IWAD type.
//
//-----------------------------------------------------------------------------

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

#include "deh_main.h"
#include "doomdef.h"
#include "doomstat.h"
#include "i_system.h"
#include "m_argv.h"
#include "m_misc.h"
#include "w_wad.h"
#include "z_zone.h"

// Array of locations to search for IWAD files

#define MAX_IWAD_DIRS 32
static char *iwad_dirs[MAX_IWAD_DIRS];
static int num_iwad_dirs = 0;

static void AddIWADDir(char *dir)
{
    iwad_dirs[num_iwad_dirs] = dir;
    ++num_iwad_dirs;
}

// This is Windows-specific code that automatically finds the location
// of installed IWAD files.  The registry is inspected to find special
// keys installed by the Windows installers for various CD versions
// of Doom.  From these keys we can deduce where to find an IWAD.

#ifdef _WIN32

#define WIN32_LEAN_AND_MEAN
#include <windows.h>

typedef struct 
{
    HKEY root;
    char *path;
    char *value;
} registry_value_t;

#define UNINSTALLER_STRING "\\uninstl.exe /S "

// Keys installed by the various CD editions.  These are actually the 
// commands to invoke the uninstaller and look like this:
//
// C:\Program Files\Path\uninstl.exe /S C:\Program Files\Path
//
// With some munging we can find where Doom was installed.

static registry_value_t uninstall_values[] = 
{
    // Ultimate Doom, CD version (Depths of Doom trilogy)

    {
        HKEY_LOCAL_MACHINE, 
        "Software\\Microsoft\\Windows\\CurrentVersion\\"
            "Uninstall\\Ultimate Doom for Windows 95",
        "UninstallString",
    },

    // Doom II, CD version (Depths of Doom trilogy)

    {
        HKEY_LOCAL_MACHINE, 
        "Software\\Microsoft\\Windows\\CurrentVersion\\"
            "Uninstall\\Doom II for Windows 95",
        "UninstallString",
    },

    // Final Doom

    {
        HKEY_LOCAL_MACHINE, 
        "Software\\Microsoft\\Windows\\CurrentVersion\\"
            "Uninstall\\Final Doom for Windows 95",
        "UninstallString",
    },

    // Shareware version

    {
        HKEY_LOCAL_MACHINE, 
        "Software\\Microsoft\\Windows\\CurrentVersion\\"
            "Uninstall\\Doom Shareware for Windows 95",
        "UninstallString",
    },
};

// Value installed by the Collector's Edition when it is installed

static registry_value_t collectors_edition_value =
{
    HKEY_LOCAL_MACHINE,
    "Software\\Activision\\DOOM Collector's Edition\\v1.0",
    "INSTALLPATH",
};

// Subdirectories of the above install path, where IWADs are installed.

static char *collectors_edition_subdirs[] = 
{
    "Doom2",
    "Final Doom",
    "Ultimate Doom",
};

static char *GetRegistryString(registry_value_t *reg_val)
{
    HKEY key;
    DWORD len;
    DWORD valtype;
    char *result;

    // Open the key (directory where the value is stored)

    if (RegOpenKeyEx(reg_val->root, reg_val->path, 0, KEY_READ, &key) 
          != ERROR_SUCCESS)
    {
        return NULL;
    }

    // Find the type and length of the string

    if (RegQueryValueEx(key, reg_val->value, NULL, &valtype, NULL, &len) 
          != ERROR_SUCCESS)
    {
        return NULL;
    }

    // Only accept strings

    if (valtype != REG_SZ)
    {
        return NULL;
    }

    // Allocate a buffer for the value and read the value

    result = Z_Malloc(len, PU_STATIC, 0);

    if (RegQueryValueEx(key, reg_val->value, NULL, &valtype, (unsigned char *) result, &len) 
          != ERROR_SUCCESS)
    {
        Z_Free(result);
        return NULL;
    }

    // Close the key
        
    RegCloseKey(key);

    return result;
}

// Check for the uninstall strings from the CD versions

static void CheckUninstallStrings(void)
{
    int i;

    for (i=0; i<sizeof(uninstall_values) / sizeof(*uninstall_values); ++i)
    {
        char *val;
        char *path;
        char *unstr;

        val = GetRegistryString(&uninstall_values[i]);

        if (val == NULL)
        {
            continue;
        }

        unstr = strstr(val, UNINSTALLER_STRING);

        if (unstr == NULL)
        {
            Z_Free(val);
        }
        else
        {
            path = unstr + strlen(UNINSTALLER_STRING);

            AddIWADDir(path);
        }
    }
}

// Check for Doom: Collector's Edition

static void CheckCollectorsEdition(void)
{
    char *install_path;
    char *subpath;
    int i;

    install_path = GetRegistryString(&collectors_edition_value);

    if (install_path == NULL)
    {
        return;
    }

    for (i=0; i<sizeof(collectors_edition_subdirs)
                  / sizeof(*collectors_edition_subdirs); ++i)
    {
        subpath = Z_Malloc(strlen(install_path)
                           + strlen(collectors_edition_subdirs[i])
                           + 5,
                           PU_STATIC, 0);

        sprintf(subpath, "%s\\%s", install_path, collectors_edition_subdirs[i]);

        AddIWADDir(subpath);
    }

    Z_Free(install_path);
}

#endif

static struct 
{
    char *name;
    GameMission_t mission;
} iwads[] = {
    {"doom2.wad",    doom2},
    {"plutonia.wad", pack_plut},
    {"tnt.wad",      pack_tnt},
    {"doom.wad",     doom},
    {"doom1.wad",    doom},
};

// Search a directory to try to find an IWAD
// Returns the location of the IWAD if found, otherwise NULL.

static char *SearchDirectoryForIWAD(char *dir)
{
    size_t i;

    for (i=0; i<sizeof(iwads) / sizeof(*iwads); ++i) 
    {
        char *filename; 
        char *iwadname;

        iwadname = DEH_String(iwads[i].name);
        
        filename = Z_Malloc(strlen(dir) + strlen(iwadname) + 3, PU_STATIC, 0);

        sprintf(filename, "%s/%s", dir, iwadname);

        if (M_FileExists(filename))
        {
            gamemission = iwads[i].mission;
            return filename;
        }

        Z_Free(filename);
    }

    return NULL;
}

// When given an IWAD with the '-iwad' parameter,
// attempt to identify it by its name.

static void IdentifyIWADByName(char *name)
{
    size_t i;

    gamemission = none;
    
    for (i=0; i<sizeof(iwads) / sizeof(*iwads); ++i)
    {
        char *iwadname;

        iwadname = DEH_String(iwads[i].name);

        if (strlen(name) < strlen(iwadname))
            continue;

        // Check if it ends in this IWAD name.

        if (!strcasecmp(name + strlen(name) - strlen(iwadname), 
                        iwadname))
        {
            gamemission = iwads[i].mission;
            break;
        }
    }
}

//
// Build a list of IWAD files
//

static void BuildIWADDirList(void)
{
    char *doomwaddir;

    // Check the DOOMWADDIR environment variable.

    doomwaddir = getenv("DOOMWADDIR");

    if (doomwaddir != NULL)
    {
        AddIWADDir(doomwaddir);
    }

    // Look in the current directory.  Doom always does this.

    AddIWADDir(".");

#ifdef _WIN32

    // Search the registry and find where IWADs have been installed.

    CheckUninstallStrings();
    CheckCollectorsEdition();

#else

    // Standard places where IWAD files are installed under Unix.

    AddIWADDir("/usr/share/games/doom");
    AddIWADDir("/usr/local/share/games/doom");

#endif
}

//
// FindIWAD
// Checks availability of IWAD files by name,
// to determine whether registered/commercial features
// should be executed (notably loading PWADs).
//

char *D_FindIWAD(void)
{
    char *result;
    int iwadparm;
    int i;

    iwadparm = M_CheckParm("-iwad");

    if (iwadparm)
    {
        result = myargv[iwadparm + 1];
        IdentifyIWADByName(result);
    }
    else
    {
        // Build a list of locations to look for an IWAD

        BuildIWADDirList();

        // Search through the list and look for an IWAD

        result = NULL;

        for (i=0; result == NULL && i<num_iwad_dirs; ++i)
        {
            result = SearchDirectoryForIWAD(iwad_dirs[i]);
        }
    }

    return result;
}

// 
// SetSaveGameDir
//
// Chooses the directory used to store saved games.
//

void D_SetSaveGameDir(void)
{
    size_t i;

    if (!strcmp(configdir, ""))
    {
        // Use the current directory, just like configdir.

        savegamedir = strdup("");
    }
    else
    {
        // Directory for savegames

        savegamedir = Z_Malloc(strlen(configdir) + 30, PU_STATIC, 0);
        sprintf(savegamedir, "%ssavegames", configdir);

        M_MakeDirectory(savegamedir);

        // Find what subdirectory to use for savegames
        //
        // They should be stored in something like
        //    ~/.chocolate-doom/savegames/doom.wad/
        //
        // The directory depends on the IWAD, so that savegames for
        // different IWADs are kept separate.
        //
        // Note that we match on gamemission rather than on IWAD name.
        // This ensures that doom1.wad and doom.wad saves are stored
        // in the same place.

        for (i=0; i<sizeof(iwads) / sizeof(*iwads); ++i)
        {
            if (gamemission == iwads[i].mission)
            {
                strcat(savegamedir, "/");
                strcat(savegamedir, iwads[i].name);
                strcat(savegamedir, "/");
                M_MakeDirectory(savegamedir);
                break;
            }
        }
    }
}

// Strings for dehacked replacements of the startup banner
//
// These are from the original source: some of them are perhaps
// not used in any dehacked patches

static char *banners[] = 
{
    // doom1.wad
    "                            "
    "DOOM Shareware Startup v%i.%i"
    "                           ",
    // doom.wad
    "                            "
    "DOOM Registered Startup v%i.%i"
    "                           ",
    // Registered DOOM uses this
    "                          "
    "DOOM System Startup v%i.%i"
    "                          ",
    // doom.wad (Ultimate DOOM)
    "                         "
    "The Ultimate DOOM Startup v%i.%i"
    "                        ",
    // doom2.wad
    "                         "
    "DOOM 2: Hell on Earth v%i.%i"
    "                           ",
    // tnt.wad
    "                     "
    "DOOM 2: TNT - Evilution v%i.%i"
    "                           ",
    // plutonia.wad
    "                   "
    "DOOM 2: Plutonia Experiment v%i.%i"
    "                           ",
};

//
// Get game name: if the startup banner has been replaced, use that.
// Otherwise, use the name given
// 

static char *GetGameName(char *gamename)
{
    size_t i;
    char *deh_sub;
    
    for (i=0; i<sizeof(banners) / sizeof(*banners); ++i)
    {
        // Has the banner been replaced?

        deh_sub = DEH_String(banners[i]);
        
        if (deh_sub != banners[i])
        {
            // Has been replaced
            // We need to expand via printf to include the Doom version 
            // number
            // We also need to cut off spaces to get the basic name

            gamename = Z_Malloc(strlen(deh_sub) + 10, PU_STATIC, 0);
            sprintf(gamename, deh_sub, DOOM_VERSION / 100, DOOM_VERSION % 100);

            while (gamename[0] != '\0' && isspace(gamename[0]))
                strcpy(gamename, gamename+1);

            while (gamename[0] != '\0' && isspace(gamename[strlen(gamename)-1]))
                gamename[strlen(gamename) - 1] = '\0';
            
            return gamename;
        }
    }

    return gamename;
}


//
// Find out what version of Doom is playing.
//

void D_IdentifyVersion(void)
{
    // gamemission is set up by the D_FindIWAD function.  But if 
    // we specify '-iwad', we have to identify using 
    // IdentifyIWADByName.  However, if the iwad does not match
    // any known IWAD name, we may have a dilemma.  Try to 
    // identify by its contents.

    if (gamemission == none)
    {
        unsigned int i;

        for (i=0; i<numlumps; ++i)
        {
            if (!strncasecmp(lumpinfo[i].name, "MAP01", 8))
            {
                gamemission = doom2;
                break;
            } 
            else if (!strncasecmp(lumpinfo[i].name, "E1M1", 8))
            {
                gamemission = doom;
                break;
            }
        }

        if (gamemission == none)
        {
            // Still no idea.  I don't think this is going to work.

            I_Error("Unknown or invalid IWAD file.");
        }
    }

    // Make sure gamemode is set up correctly

    if (gamemission == doom)
    {
        // Doom 1.  But which version?

        if (W_CheckNumForName("E4M1") > 0)
        {
            // Ultimate Doom

            gamemode = retail;
        } 
        else if (W_CheckNumForName("E3M1") > 0)
        {
            gamemode = registered;
        }
        else
        {
            gamemode = shareware;
        }
    }
    else
    {
        // Doom 2 of some kind.

        gamemode = commercial;
    }
}

// Set the gamedescription string

void D_SetGameDescription(void)
{
    gamedescription = "Unknown";

    if (gamemission == doom)
    {
        // Doom 1.  But which version?

        if (gamemode == retail)
        {
            // Ultimate Doom

            gamedescription = GetGameName("The Ultimate DOOM");
        } 
        else if (gamemode == registered)
        {
            gamedescription = GetGameName("DOOM Registered");
        }
        else if (gamemode == shareware)
        {
            gamedescription = GetGameName("DOOM Shareware");
        }
    }
    else
    {
        // Doom 2 of some kind.  But which mission?

        if (gamemission == doom2)
            gamedescription = GetGameName("DOOM 2: Hell on Earth");
        else if (gamemission == pack_plut)
            gamedescription = GetGameName("DOOM 2: Plutonia Experiment"); 
        else if (gamemission == pack_tnt)
            gamedescription = GetGameName("DOOM 2: TNT - Evilution");
    }
}