/*
 *   This file is part of open_agb_firm
 *   Copyright (C) 2021 derrek, profi200
 *
 *   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 3 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, see <http://www.gnu.org/licenses/>.
 */

#include <stdlib.h>
#include <string.h>
#include "types.h"
#include "error_codes.h"
#include "fs.h"
#include "util.h"
#include "arm11/drivers/hid.h"
#include "arm11/console.h"
#include "arm11/fmt.h"
#include "drivers/gfx.h"
#include "arm11/acf.h"
#include "arm11/atp.h"
#include "arm11/acl.h"

#define screenClean() memset(consoleGet()->frameBuffer, 0, CWIDTH*CHEIGHT*sizeof(uint16_t))

// Notes on these settings:
// MAX_ENT_BUF_SIZE should be big enough to hold the average file/dir name length * MAX_DIR_ENTRIES.
#define MAX_ENT_BUF_SIZE  (1024u * 196) // 196 KiB.
#define MAX_DIR_ENTRIES   (999u)
#define DIR_READ_BLOCKS   (10u)

#define CWIDTH                  320u
#define CHEIGHT                 240u

#define ENT_TYPE_FILE  (0)
#define ENT_TYPE_DIR   (1)

typedef struct
{
	u32 num;                       // Total number of entries.
	char entBuf[MAX_ENT_BUF_SIZE]; // Format: char entryType; char name[X]; // null terminated.
	char *ptrs[MAX_DIR_ENTRIES];   // For fast sorting.
} DirList;

int dlistCompare(const void *a, const void *b)
{
	const char *entA = *(char**)a;
	const char *entB = *(char**)b;

	// Compare the entry type. Dirs have priority over files.
	if(*entA != *entB) return (int)*entB - *entA;

	// Compare the string.
	int res;
	do
	{
		res = *++entA - *++entB;
	} while(res == 0 && *entA != '\0' && *entB != '\0');

	return res;
}

static Result scanDir(const char *const path, DirList *const dList, const char *const filter, const char *match, int *index)
{
	FILINFO *const fis = (FILINFO*)malloc(sizeof(FILINFO) * DIR_READ_BLOCKS);
	if(fis == NULL) return RES_OUT_OF_MEM;

	dList->num = 0;

	Result res;
	DHandle dh;
	u32 received = 0;
	if((res = fOpenDir(&dh, path)) == RES_OK)
	{
		u32 read;           // Number of entries read by fReadDir().
		u32 numEntries = 0; // Total number of processed entries.
		u32 entBufPos = 0;  // Entry buffer position/number of bytes used.
		const u32 filterLen = strlen(filter);
		do
		{
			if((res = fReadDir(dh, fis, DIR_READ_BLOCKS, &read)) != RES_OK) break;
			received = numEntries + read;
			read = (read <= MAX_DIR_ENTRIES - numEntries ? read : MAX_DIR_ENTRIES - numEntries);

			for(u32 i = 0; i < read; i++)
			{
				const char entType = (fis[i].fattrib & AM_DIR ? ENT_TYPE_DIR : ENT_TYPE_FILE);
				const u32 nameLen = strlen(fis[i].fname);
				if(entType == ENT_TYPE_FILE)
				{
					if(nameLen <= filterLen || strcmp(filter, fis[i].fname + nameLen - filterLen) != 0)
						continue;
				}

				// nameLen does not include the entry type and NULL termination.
				if(entBufPos + nameLen + 2 > MAX_ENT_BUF_SIZE) 
				{
					res = RES_PATH_TOO_LONG;
					goto scanEnd;
				}

				char *const entry = &dList->entBuf[entBufPos];
				*entry = entType;
				safeStrcpy(&entry[1], fis[i].fname, 256);
				dList->ptrs[numEntries++] = entry;
				entBufPos += nameLen + 2;
			}
		} while(read == DIR_READ_BLOCKS);

scanEnd:
		dList->num = numEntries;

		fCloseDir(dh);
	}

	free(fis);

	qsort(dList->ptrs, dList->num, sizeof(char*), dlistCompare);

	if( match != NULL )
	{
		for( u32 i=0; i < dList->num; ++i )
		{
			if( strcmp(match, &dList->ptrs[i][1]) == 0 )
			{
				*index = i;
				break;
			}
		}
	}

	return received > MAX_DIR_ENTRIES ? RES_OUT_OF_RANGE :  res;
}

static Result rom_get_serial( const char *file, char serial[5] )
{
	FHandle f;
	Result res;
	u32 readed;
	serial[0] = serial[4] = '\0';
	if( RES_OK != (res=fOpen(&f, file, FA_OPEN_EXISTING | FA_READ)) )
	{
		return res;
	}
	if( RES_OK != (res=fLseek(f, 0xac)) )
	{
		fClose( f );
		return res;
	}
	if( RES_OK != (res=fRead(f, serial, 4, &readed)) 
		|| readed != 4 )
	{
		fClose(f);
		return res;
	}
	fClose(f);
	return RES_OK;
}

static atp_text_t folder_help[] = {
	"操 作 说 明",
	"~    ~    ~    ~    ~    ~    ~",
	"蓝色　　　　　　　　　　　　　目录",
	"白色　　　　　　　　　　　　　游戏",
	"~    ~    ~    ~    ~    ~    ~",
	"上下方向键　　　切换选中文件或目录",
	"左右方向键　　　　　　　　　　翻页",
	"Ａ键　　　　　　查看目录或启动游戏",
	"Ｂ键　　　　　　　　　　上层文件夹",
	"Ｘ键　　　　　　　　　　　　金手指",
	"Ｙ键　　　　　　　　　　　暂不使用",
	"ＳＴＡＲＴ　　　　　　　　查看说明",
	"ＳＥＬＥＣＴ　　　　　　　系统设置"
};

static atp_error_t display_folder( atp_callerdata_t data, atp_counter_t index, atp_itemcfg_t *config )
{
	void* *dat = (void **)data;
	DirList *const dList = (DirList*)dat[0];
	u8 type = *dList->ptrs[index];
	if( type == ENT_TYPE_DIR )
		config->text_color = ATP_COLOR_BLUE;
	config->text = &dList->ptrs[index][1];
	config->value = index;
	return ATP_SUCCESS;
}

#define DECLARE_ERROR_PAGE(name, message) 	static atp_error_t name (atp_callerdata_t, atp_counter_t, atp_linecfg_t *c) \
											{ \
												c->text = message; \
												c->text_align = ATP_PLACEMENT_CENTER; \
												c->text_color = ATP_COLOR_RED; \
												return ATP_SUCCESS; \
											}

DECLARE_ERROR_PAGE( display_openlib, "打开金手指文件出错" )
DECLARE_ERROR_PAGE( display_selcht, "查找金手指配置出错" )
DECLARE_ERROR_PAGE( display_noserial, "提取游戏识别码失败" )
DECLARE_ERROR_PAGE( display_nocheat, "找不到对应的金手指配置" )
DECLARE_ERROR_PAGE( display_empty, "没有合适的文件" )
DECLARE_ERROR_PAGE( display_toolong, "路径过长，改名或移动文件后再试" )
DECLARE_ERROR_PAGE( display_pathfull, "游戏或目录过量，最多显示999个" )
DECLARE_ERROR_PAGE( display_longname, "文件名总计过长，只显示前面的文件" )

DECLARE_ERROR_PAGE( display_ok, "ok" )

static atp_error_t display_help( atp_callerdata_t table, atp_counter_t index, atp_linecfg_t *config )
{
	atp_text_t *list = (atp_text_t*)table;
	config->text_align = ATP_PLACEMENT_CENTER;
	config->text_color = index == 0 ? ATP_COLOR_MAGENTA : ATP_COLOR_LIGHT;
	config->text = list[index];
	return ATP_SUCCESS;
}

atp_error_t help_page( atp_text_t *wording, atp_counter_t length )
{
	atp_tips( NULL, "返回：按A/B" );
	atp_error_t res = atp_show( length, display_help, (atp_callerdata_t)wording );
	atp_tips( NULL, "指引：按START" );
	return res;
}

atp_error_t select_region( atp_callerdata_t data, atp_counter_t index, atp_itemcfg_t *config )
{
	static char text[16];
	acl_chtid_t sid;
	acl_region_t sreg;
	char *p = data;
	char *t;
	acl_query_cheat_set(index, &sid, &sreg);
	if( sreg == p[0] ) p[1]++;
	else 
	{
		p[0] = sreg;
		p[1] = 'A';
	}
	switch( sreg )
	{
		case 'C': t = "官方中文"; break;
		case 'J': t = "日文版"; break;
		case 'E': t = "英文版"; break;
		case 'F': t = "法语版"; break;
		case 'S': t = "西班牙语"; break;
		case 'I': t = "意大利语"; break;
		case 'D': t = "德语版"; break;
		default: t = "其他语种"; break;
	}
	ee_sprintf(text, "%s-%c", t, p[1]);
	config->text = text;
	config->value = sreg;
	return ATP_SUCCESS;
}

extern atp_error_t oaf_config_page();

#define DIRBUFFSIZE 512
#define WAIT_ON_ACT( act ) ( ATP_POWER_OFF == (act) ) ? ATP_POWER_OFF : ATP_PAGE_REFRESH
#define WAIT_ON_ERRPAGE( page ) WAIT_ON_ACT( atp_show(1, (page), NULL) )

static atp_pageopt_t serve_on_key( atp_callerdata_t data, atp_counter_t index, atp_boolean_t x, atp_boolean_t y, atp_boolean_t l, atp_boolean_t r, atp_boolean_t start, atp_boolean_t select )
{
	if( start )
	{
		atp_tips( "", NULL );
		return WAIT_ON_ACT( help_page( folder_help, sizeof(folder_help)/sizeof(atp_text_t) ) );
	}
	else if( select )
	{
		return WAIT_ON_ACT( oaf_config_page() );
	}
	else if( x )
	{
		void* *dat = (void **)data;
		DirList const *dList = (DirList*)dat[0];
		char *path = (char*)dat[1];

		const char *file = &dList->ptrs[index][1];
		int pathlen = strlen(path);
		int filelen = strlen(file);

		if( pathlen + filelen > DIRBUFFSIZE - 1)
		{
			return WAIT_ON_ERRPAGE( display_toolong );
		}
		else if( ENT_TYPE_DIR == dList->ptrs[index][0] )
		{
			return WAIT_ON_ERRPAGE( display_empty );
		}

		path[pathlen] = '/';
		safeStrcpy( path+pathlen+1, file, DIRBUFFSIZE - filelen );

#define RECOVER_PATH path[pathlen] = '\0'
		// 确定game serial
		char serial[5];
		if( RES_OK != rom_get_serial(path, serial) )
		{
			RECOVER_PATH;
			return WAIT_ON_ERRPAGE( display_noserial );
		}
		else RECOVER_PATH;

		acl_count_t len;
		if( RES_OK != acl_open_lib( "gba.acl" ) )
		{
			return WAIT_ON_ERRPAGE( display_openlib );
		}
		if( RES_OK != acl_select_game( serial, 0, &len ) )
		{
			acl_close_lib();
			return WAIT_ON_ERRPAGE( display_selcht );
		}
		if( len == 0 )
		{
			atp_tips( "", NULL );
			acl_close_lib();
			serial[5] = 'a'+len;
			fsQuickWrite("serial.txt", serial, 5);
			return WAIT_ON_ERRPAGE( display_nocheat );
		}

		fsQuickWrite("serial.txt", serial, 4);
		
		// 显示配置页面
		atp_error_t res;
		atp_itemval_t item;
		char type[2] = {' ', 'A'};
		res = atp_select("选择一个金手指配置", len, select_region, NULL, type, 0, 0, &item );

		acl_close_lib();
		return WAIT_ON_ACT( res );
	}
	return ATP_PAGE_NOOPTION;
}

#define PATH_SAME 0
#define PATH_PUSH 1
#define PATH_POP  2
#define DIRUP 	{ \
					char *tmpPathPtr = curDir + pathLen; \
					while(*--tmpPathPtr != '/'); \
					if(*(tmpPathPtr - 1) == ':') tmpPathPtr++; \
					*tmpPathPtr = '\0'; \
					path_recover = PATH_POP; \
					upFrom = tmpPathPtr + 1; \
				}
Result browseFiles(const char *const basePath, char selected[512])
{
	if(basePath == NULL || selected == NULL) return RES_INVALID_ARG;
	// TODO: Check if the base path is empty.

	char *curDir = (char*)malloc(DIRBUFFSIZE);
	if(curDir == NULL) return RES_OUT_OF_MEM;
	safeStrcpy(curDir, basePath, 512);

	DirList *const dList = (DirList*)malloc(sizeof(DirList));
	if(dList == NULL) return RES_OUT_OF_MEM;

	Result res;
	if((res = scanDir(curDir, dList, ".gba", NULL, NULL)) != RES_OK) 
	{
		if( res == RES_OUT_OF_RANGE )
			atp_show(1, display_pathfull, NULL);
		else if( res == RES_PATH_TOO_LONG )
			atp_show(1, display_longname, NULL );
		else goto end;
	}
	
	const char *upFrom = NULL;
	int selecting = 0;
	while( 1 )
	{
		atp_itemval_t value;
		atp_error_t error;
		int path_recover = PATH_SAME;
		const u32 count = dList->num;

		u32 pathLen = strlen(curDir);

		if( count > 0 )
		{
			GFX_waitForVBlank0();
        	hidScanInput();
			atp_tips( NULL, "指引：按START" );
			void *cust[2] = {dList, curDir};
			error = atp_select( curDir, count, display_folder, serve_on_key, (atp_callerdata_t)cust, selecting, 0, &value );
		}
		else error = atp_show( 1, display_empty, NULL );

		if( error == ATP_POWER_OFF )
		{
			res = error;
			break;
		}
		else if( error == ATP_SUCCESS )
		{// 进入目录或文件
			if( count == 0 )
			{
				DIRUP;
			}
			else 
			{
				const char *fname = &dList->ptrs[value][1];
				u32 namelen = strlen( fname ) + 1;
				if( namelen + pathLen > DIRBUFFSIZE-1 )
				{
					atp_show( 1, display_toolong, NULL );
					continue;
				}
				curDir[pathLen++] = '/';
				safeStrcpy( curDir+pathLen, fname, DIRBUFFSIZE - namelen );
				if( *dList->ptrs[value] == ENT_TYPE_FILE )
				{
					safeStrcpy( selected, curDir, 512 );
					break;
				}
				else 
				{
					path_recover = PATH_PUSH;
					selecting = 0;
					upFrom = NULL;
				}
			}
		}
		else if( error == ATP_NO_ACTION )
		{// 上层目录
			if( strcmp(curDir, FS_DRIVE_NAMES) == 0 )
			{
				atp_tips("没有上层目录", NULL);
				help_page( folder_help, sizeof(folder_help)/sizeof(atp_text_t) );
				atp_tips("", NULL);
			}
			else DIRUP;
		}

		if( path_recover )
		{
			if(RES_OK != (res = scanDir(curDir, dList, ".gba", upFrom, &selecting)) )
			{
				if( res == RES_OUT_OF_RANGE )
					atp_show( 1, display_pathfull, NULL );	// give a warning for user, and keep show the list
				else if( res == RES_PATH_TOO_LONG )
					atp_show( 1, display_longname, NULL );
				else break;
			}
			path_recover = PATH_SAME;
		}
	}

end:
	free(dList);
	free(curDir);

	// Clear screen.
	screenClean();

	return res;
}