//
// Copyright(C) 2005-2014 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.
//
// DESCRIPTION:
// Handles merging of PWADs, similar to deutex's -merge option
//
// Ideally this should work exactly the same as in deutex, but trying to
// read the deutex source code made my brain hurt.
//

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

#include "doomtype.h"
#include "i_system.h"
#include "m_misc.h"
#include "w_merge.h"
#include "w_wad.h"
#include "z_zone.h"

typedef enum 
{ 
    SECTION_NORMAL, 
    SECTION_FLATS, 
    SECTION_SPRITES,
} section_t;

typedef struct
{
    lumpinfo_t *lumps;
    int numlumps;
} searchlist_t;

typedef struct
{
    char sprname[4];
    char frame;
    lumpinfo_t *angle_lumps[8];
} sprite_frame_t;

static searchlist_t iwad;
static searchlist_t iwad_sprites;
static searchlist_t pwad;

static searchlist_t iwad_flats;
static searchlist_t pwad_sprites;
static searchlist_t pwad_flats;

// lumps with these sprites must be replaced in the IWAD
static sprite_frame_t *sprite_frames;
static int num_sprite_frames;
static int sprite_frames_alloced;

// Search in a list to find a lump with a particular name
// Linear search (slow!)
//
// Returns -1 if not found

static int FindInList(searchlist_t *list, char *name)
{
    int i;

    for (i=0; i<list->numlumps; ++i)
    {
        if (!strncasecmp(list->lumps[i].name, name, 8))
            return i;
    }

    return -1;
}

static boolean SetupList(searchlist_t *list, searchlist_t *src_list,
                         char *startname, char *endname,
                         char *startname2, char *endname2)
{
    int startlump, endlump;

    list->numlumps = 0;
    startlump = FindInList(src_list, startname);

    if (startname2 != NULL && startlump < 0)
    {
        startlump = FindInList(src_list, startname2);
    }

    if (startlump >= 0)
    {
        endlump = FindInList(src_list, endname);

        if (endname2 != NULL && endlump < 0)
        {
            endlump = FindInList(src_list, endname2);
        }

        if (endlump > startlump)
        {
            list->lumps = src_list->lumps + startlump + 1;
            list->numlumps = endlump - startlump - 1;
            return true;
        }
    }

    return false;
}

// Sets up the sprite/flat search lists

static void SetupLists(void)
{
    // IWAD

    if (!SetupList(&iwad_flats, &iwad, "F_START", "F_END", NULL, NULL))
    {
        I_Error("Flats section not found in IWAD");
    }

    if (!SetupList(&iwad_sprites, &iwad, "S_START", "S_END", NULL, NULL))

    {
        I_Error("Sprites section not found in IWAD");
    }
    
    // PWAD

    SetupList(&pwad_flats, &pwad, "F_START", "F_END", "FF_START", "FF_END");
    SetupList(&pwad_sprites, &pwad, "S_START", "S_END", "SS_START", "SS_END");
}

// Initialize the replace list

static void InitSpriteList(void)
{
    if (sprite_frames == NULL)
    {
        sprite_frames_alloced = 128;
        sprite_frames = Z_Malloc(sizeof(*sprite_frames) * sprite_frames_alloced,
                                 PU_STATIC, NULL);
    }

    num_sprite_frames = 0;
}

static boolean ValidSpriteLumpName(char *name)
{
    if (name[0] == '\0' || name[1] == '\0'
     || name[2] == '\0' || name[3] == '\0')
    {
        return false;
    }

    // First frame:

    if (name[4] == '\0' || !isdigit(name[5]))
    {
        return false;
    }

    // Second frame (optional):

    if (name[6] != '\0' && !isdigit(name[7]))
    {
        return false;
    }

    return true;
}

// Find a sprite frame

static sprite_frame_t *FindSpriteFrame(char *name, int frame)
{
    sprite_frame_t *result;
    int i;

    // Search the list and try to find the frame

    for (i=0; i<num_sprite_frames; ++i)
    {
        sprite_frame_t *cur = &sprite_frames[i];

        if (!strncasecmp(cur->sprname, name, 4) && cur->frame == frame)
        {
            return cur;
        }
    }

    // Not found in list; Need to add to the list

    // Grow list?

    if (num_sprite_frames >= sprite_frames_alloced)
    {
        sprite_frame_t *newframes;

        newframes = Z_Malloc(sprite_frames_alloced * 2 * sizeof(*sprite_frames),
                             PU_STATIC, NULL);
        memcpy(newframes, sprite_frames,
               sprite_frames_alloced * sizeof(*sprite_frames));
        Z_Free(sprite_frames);
        sprite_frames_alloced *= 2;
        sprite_frames = newframes;
    }

    // Add to end of list
    
    result = &sprite_frames[num_sprite_frames];
    strncpy(result->sprname, name, 4);
    result->frame = frame;

    for (i=0; i<8; ++i)
        result->angle_lumps[i] = NULL;

    ++num_sprite_frames;

    return result;
}

// Check if sprite lump is needed in the new wad

static boolean SpriteLumpNeeded(lumpinfo_t *lump)
{
    sprite_frame_t *sprite;
    int angle_num;
    int i;

    if (!ValidSpriteLumpName(lump->name))
    {
        return true;
    }

    // check the first frame

    sprite = FindSpriteFrame(lump->name, lump->name[4]);
    angle_num = lump->name[5] - '0';

    if (angle_num == 0)
    {
        // must check all frames

        for (i=0; i<8; ++i)
        {
            if (sprite->angle_lumps[i] == lump)
                return true;
        }
    }
    else 
    {
        // check if this lump is being used for this frame

        if (sprite->angle_lumps[angle_num - 1] == lump)
            return true;
    }
            
    // second frame if any
    
    // no second frame?
    if (lump->name[6] == '\0')
        return false;

    sprite = FindSpriteFrame(lump->name, lump->name[6]);
    angle_num = lump->name[7] - '0';

    if (angle_num == 0)
    {
        // must check all frames

        for (i=0; i<8; ++i)
        {
            if (sprite->angle_lumps[i] == lump)
                return true;
        }
    }
    else 
    {
        // check if this lump is being used for this frame

        if (sprite->angle_lumps[angle_num - 1] == lump)
            return true;
    }

    return false;
}

static void AddSpriteLump(lumpinfo_t *lump)
{
    sprite_frame_t *sprite;
    int angle_num;
    int i;

    if (!ValidSpriteLumpName(lump->name))
    {
        return;
    }
    
    // first angle

    sprite = FindSpriteFrame(lump->name, lump->name[4]);
    angle_num = lump->name[5] - '0';
    
    if (angle_num == 0) 
    {
        for (i=0; i<8; ++i)
            sprite->angle_lumps[i] = lump;
    }
    else
    {
        sprite->angle_lumps[angle_num - 1] = lump;
    }
    
    // second angle

    // no second angle?
  
    if (lump->name[6] == '\0')
        return;
    
    sprite = FindSpriteFrame(lump->name, lump->name[6]);
    angle_num = lump->name[7] - '0';
    
    if (angle_num == 0) 
    {
        for (i=0; i<8; ++i)
            sprite->angle_lumps[i] = lump;
    }
    else
    {
        sprite->angle_lumps[angle_num - 1] = lump;
    }
}

// Generate the list.  Run at the start, before merging

static void GenerateSpriteList(void)
{
    int i;

    InitSpriteList();
    
    // Add all sprites from the IWAD
    
    for (i=0; i<iwad_sprites.numlumps; ++i)
    {
        AddSpriteLump(&iwad_sprites.lumps[i]);
    }
    
    // Add all sprites from the PWAD
    // (replaces IWAD sprites)

    for (i=0; i<pwad_sprites.numlumps; ++i)
    {
        AddSpriteLump(&pwad_sprites.lumps[i]);
    }
}

// Perform the merge.
//
// The merge code creates a new lumpinfo list, adding entries from the
// IWAD first followed by the PWAD.
//
// For the IWAD:
//  * Flats are added.  If a flat with the same name is in the PWAD, 
//    it is ignored(deleted).  At the end of the section, all flats in the 
//    PWAD are inserted.  This is consistent with the behavior of 
//    deutex/deusf.
//  * Sprites are added.  The "replace list" is generated before the merge
//    from the list of sprites in the PWAD.  Any sprites in the IWAD found
//    to match the replace list are removed.  At the end of the section,
//    the sprites from the PWAD are inserted.
// 
// For the PWAD:
//  * All Sprites and Flats are ignored, with the assumption they have 
//    already been merged into the IWAD's sections.

static void DoMerge(void)
{
    section_t current_section;
    lumpinfo_t *newlumps;
    int num_newlumps;
    int lumpindex;
    int i, n;
    
    // Can't ever have more lumps than we already have
    newlumps = malloc(sizeof(lumpinfo_t) * numlumps);
    num_newlumps = 0;

    // Add IWAD lumps
    current_section = SECTION_NORMAL;

    for (i=0; i<iwad.numlumps; ++i)
    {
        lumpinfo_t *lump = &iwad.lumps[i];

        switch (current_section)
        {
            case SECTION_NORMAL:
                if (!strncasecmp(lump->name, "F_START", 8))
                {
                    current_section = SECTION_FLATS;
                }
                else if (!strncasecmp(lump->name, "S_START", 8))
                {
                    current_section = SECTION_SPRITES;
                }

                newlumps[num_newlumps++] = *lump;

                break;

            case SECTION_FLATS:

                // Have we reached the end of the section?

                if (!strncasecmp(lump->name, "F_END", 8))
                {
                    // Add all new flats from the PWAD to the end
                    // of the section

                    for (n=0; n<pwad_flats.numlumps; ++n)
                    {
                        newlumps[num_newlumps++] = pwad_flats.lumps[n];
                    }

                    newlumps[num_newlumps++] = *lump;

                    // back to normal reading
                    current_section = SECTION_NORMAL;
                }
                else
                {
                    // If there is a flat in the PWAD with the same name,
                    // do not add it now.  All PWAD flats are added to the
                    // end of the section. Otherwise, if it is only in the
                    // IWAD, add it now

                    lumpindex = FindInList(&pwad_flats, lump->name);

                    if (lumpindex < 0)
                    {
                        newlumps[num_newlumps++] = *lump;
                    }
                }

                break;

            case SECTION_SPRITES:

                // Have we reached the end of the section?

                if (!strncasecmp(lump->name, "S_END", 8))
                {
                    // add all the pwad sprites

                    for (n=0; n<pwad_sprites.numlumps; ++n)
                    {
                        if (SpriteLumpNeeded(&pwad_sprites.lumps[n]))
                        {
                            newlumps[num_newlumps++] = pwad_sprites.lumps[n];
                        }
                    }

                    // copy the ending
                    newlumps[num_newlumps++] = *lump;

                    // back to normal reading
                    current_section = SECTION_NORMAL;
                }
                else
                {
                    // Is this lump holding a sprite to be replaced in the
                    // PWAD? If so, wait until the end to add it.

                    if (SpriteLumpNeeded(lump))
                    {
                        newlumps[num_newlumps++] = *lump;
                    }
                }

                break;
        }
    }
   
    // Add PWAD lumps
    current_section = SECTION_NORMAL;

    for (i=0; i<pwad.numlumps; ++i)
    {
        lumpinfo_t *lump = &pwad.lumps[i];

        switch (current_section)
        {
            case SECTION_NORMAL:
                if (!strncasecmp(lump->name, "F_START", 8)
                 || !strncasecmp(lump->name, "FF_START", 8))
                {
                    current_section = SECTION_FLATS;
                }
                else if (!strncasecmp(lump->name, "S_START", 8)
                      || !strncasecmp(lump->name, "SS_START", 8))
                {
                    current_section = SECTION_SPRITES;
                }
                else
                {
                    // Don't include the headers of sections
       
                    newlumps[num_newlumps++] = *lump;
                }
                break;

            case SECTION_FLATS:

                // PWAD flats are ignored (already merged)
  
                if (!strncasecmp(lump->name, "FF_END", 8)
                 || !strncasecmp(lump->name, "F_END", 8))
                {
                    // end of section
                    current_section = SECTION_NORMAL;
                }
                break;

            case SECTION_SPRITES:

                // PWAD sprites are ignored (already merged)

                if (!strncasecmp(lump->name, "SS_END", 8)
                 || !strncasecmp(lump->name, "S_END", 8))
                {
                    // end of section
                    current_section = SECTION_NORMAL;
                }
                break;
        }
    }

    // Switch to the new lumpinfo, and free the old one

    free(lumpinfo);
    lumpinfo = newlumps;
    numlumps = num_newlumps;

}

void W_PrintDirectory(void)
{
    unsigned int i, n;

    // debug
    for (i=0; i<numlumps; ++i)
    {
        for (n=0; n<8 && lumpinfo[i].name[n] != '\0'; ++n)
            putchar(lumpinfo[i].name[n]);
        putchar('\n');
    }
}

// Merge in a file by name

void W_MergeFile(char *filename)
{
    int old_numlumps;

    old_numlumps = numlumps;

    // Load PWAD

    if (W_AddFile(filename) == NULL)
        return;

    // iwad is at the start, pwad was appended to the end

    iwad.lumps = lumpinfo;
    iwad.numlumps = old_numlumps;

    pwad.lumps = lumpinfo + old_numlumps;
    pwad.numlumps = numlumps - old_numlumps;
    
    // Setup sprite/flat lists

    SetupLists();

    // Generate list of sprites to be replaced by the PWAD

    GenerateSpriteList();

    // Perform the merge

    DoMerge();
}

// Replace lumps in the given list with lumps from the PWAD

static void W_NWTAddLumps(searchlist_t *list)
{
    int i;

    // Go through the IWAD list given, replacing lumps with lumps of 
    // the same name from the PWAD

    for (i=0; i<list->numlumps; ++i)
    {
        int index;

        index = FindInList(&pwad, list->lumps[i].name);

        if (index > 0)
        {
            memcpy(&list->lumps[i], &pwad.lumps[index], 
                   sizeof(lumpinfo_t));
        }
    }
    
}

// Merge sprites and flats in the way NWT does with its -af and -as 
// command-line options.

void W_NWTMergeFile(char *filename, int flags)
{
    int old_numlumps;

    old_numlumps = numlumps;

    // Load PWAD

    if (W_AddFile(filename) == NULL)
        return;

    // iwad is at the start, pwad was appended to the end

    iwad.lumps = lumpinfo;
    iwad.numlumps = old_numlumps;

    pwad.lumps = lumpinfo + old_numlumps;
    pwad.numlumps = numlumps - old_numlumps;
    
    // Setup sprite/flat lists

    SetupLists();

    // Merge in flats?
    
    if (flags & W_NWT_MERGE_FLATS)
    {
        W_NWTAddLumps(&iwad_flats);
    }

    // Sprites?

    if (flags & W_NWT_MERGE_SPRITES)
    {
        W_NWTAddLumps(&iwad_sprites);
    }
    
    // Discard the PWAD

    numlumps = old_numlumps;
}

// Simulates the NWT -merge command line parameter.  What this does is load
// a PWAD, then search the IWAD sprites, removing any sprite lumps that also
// exist in the PWAD.

void W_NWTDashMerge(char *filename)
{
    wad_file_t *wad_file;
    int old_numlumps;
    int i;

    old_numlumps = numlumps;

    // Load PWAD

    wad_file = W_AddFile(filename);

    if (wad_file == NULL)
    {
        return;
    }

    // iwad is at the start, pwad was appended to the end

    iwad.lumps = lumpinfo;
    iwad.numlumps = old_numlumps;

    pwad.lumps = lumpinfo + old_numlumps;
    pwad.numlumps = numlumps - old_numlumps;
    
    // Setup sprite/flat lists

    SetupLists();

    // Search through the IWAD sprites list.

    for (i=0; i<iwad_sprites.numlumps; ++i)
    {
        if (FindInList(&pwad, iwad_sprites.lumps[i].name) >= 0)
        {
            // Replace this entry with an empty string.  This is what
            // nwt -merge does.

            M_StringCopy(iwad_sprites.lumps[i].name, "", 8);
        }
    }

    // Discard PWAD
    // The PWAD must now be added in again with -file.

    numlumps = old_numlumps;

    W_CloseFile(wad_file);
}