/*
 * Atmosphère Fusée Secondary Storage parser.
 *
 * Copyright (c) 2019-2020 CTCaer
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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 <string.h>

#include "fss.h"
#include "hos.h"
#include "../config.h"
#include <libs/fatfs/ff.h>
#include <mem/heap.h>
#include "../storage/emummc.h"
#include <storage/nx_sd.h>

#include <gfx_utils.h>
#define DPRINTF(...)

extern hekate_config h_cfg;

extern bool is_ipl_updated(void *buf, char *path, bool force);

// FSS0 Magic and Meta header offset.
#define FSS0_MAGIC 0x30535346
#define FSS0_META_OFFSET 0x4
#define FSS0_VERSION_0_17_0 0x110000

// FSS0 Content Types.
#define CNT_TYPE_FSP 0
#define CNT_TYPE_EXO 1  // Exosphere (Secure Monitor).
#define CNT_TYPE_WBT 2  // Warmboot (SC7Exit fw).
#define CNT_TYPE_RBT 3  // Rebootstub (Warmboot based reboot fw).
#define CNT_TYPE_SP1 4  // Sept Primary (TSEC and Sept Secondary loader).
#define CNT_TYPE_SP2 5  // Sept Secondary (Acts as pkg11 and derives keys).
#define CNT_TYPE_KIP 6  // KIP1 (Used for replacement or addition).
#define CNT_TYPE_BMP 7
#define CNT_TYPE_EMC 8
#define CNT_TYPE_KLD 9  // Kernel Loader.
#define CNT_TYPE_KRN 10 // Kernel.
#define CNT_TYPE_EXF 11 // Exosphere Mariko fatal payload.

// FSS0 Content Flags.
#define CNT_FLAG0_EXPERIMENTAL BIT(0)

// FSS0 Meta Header.
typedef struct _fss_meta_t
{
	u32 magic;
	u32 size;
	u32 crt0_off;
	u32 cnt_off;
	u32 cnt_count;
	u32 hos_ver;
	u32 version;
	u32 git_rev;
} fss_meta_t;

// FSS0 Content Header.
typedef struct _fss_content_t
{
	u32 offset;
	u32 size;
	u8 type;
	u8 flags0;
	u8 flags1;
	u8 flags2;
	u32 rsvd1;
	char name[0x10];
} fss_content_t;

int parse_fss(launch_ctxt_t *ctxt, const char *path, fss0_sept_t *sept_ctxt)
{
	FIL fp;

	bool stock = false;
	int sept_used = 0;

	// Skip if stock and Exosphere and warmboot are not needed.
	if (!sept_ctxt)
	{
		bool pkg1_old = ctxt->pkg1_id->kb <= KB_FIRMWARE_VERSION_620;
		bool emummc_disabled = !emu_cfg.enabled || h_cfg.emummc_force_disable;

		LIST_FOREACH_ENTRY(ini_kv_t, kv, &ctxt->cfg->kvs, link)
		{
			if (!strcmp("stock", kv->key))
				if (kv->val[0] == '1')
					stock = true;
		}

#ifdef HOS_MARIKO_STOCK_SECMON
		if (stock && emummc_disabled && (pkg1_old || h_cfg.t210b01))
#else
		if (stock && emummc_disabled && pkg1_old)
#endif
			return 1;
	}

	if (f_open(&fp, path, FA_READ) != FR_OK)
		return 0;

	void *fss = malloc(f_size(&fp));

	// Read first 1024 bytes of the fss file.
	f_read(&fp, fss, 1024, NULL);

	// Get FSS0 Meta header offset.
	u32 fss_meta_addr = *(u32 *)(fss + FSS0_META_OFFSET);
	fss_meta_t *fss_meta = (fss_meta_t *)(fss + fss_meta_addr);

	// Check if valid FSS0 and parse it.
	if (fss_meta->magic == FSS0_MAGIC)
	{
		bool mariko_not_supported = false;
		if (h_cfg.t210b01 && (fss_meta->version < FSS0_VERSION_0_17_0))
		{
			gfx_con.mute = false;
			mariko_not_supported = true;
		}

		gfx_printf("Found FSS0, Atmosphere %d.%d.%d-%08x\n"
			"Max HOS supported: %d.%d.%d\n"
			"Unpacking and loading components..  ",
			fss_meta->version >> 24, (fss_meta->version >> 16) & 0xFF, (fss_meta->version >> 8) & 0xFF, fss_meta->git_rev,
			fss_meta->hos_ver >> 24, (fss_meta->hos_ver >> 16) & 0xFF, (fss_meta->hos_ver >> 8) & 0xFF);

		if (mariko_not_supported)
		{
			EPRINTF("\nMariko not supported on < 0.17.0!");
			goto fail;
		}

		if (!sept_ctxt)
		{
			ctxt->atmosphere = true;
			ctxt->fss0_hosver = fss_meta->hos_ver;
		}

		// Parse FSS0 contents.
		fss_content_t *curr_fss_cnt = (fss_content_t *)(fss + fss_meta->cnt_off);
		void *content;
		for (u32 i = 0; i < fss_meta->cnt_count; i++)
		{
			content = (void *)(fss + curr_fss_cnt[i].offset);

			// Check if offset is inside limits.
			if ((curr_fss_cnt[i].offset + curr_fss_cnt[i].size) > fss_meta->size)
				continue;

			// If content is experimental and experimental flag is not enabled, skip it.
			if ((curr_fss_cnt[i].flags0 & CNT_FLAG0_EXPERIMENTAL) && !ctxt->fss0_experimental)
				continue;

			// Parse content.
			if (!sept_ctxt)
			{
				// Prepare content context.
				switch (curr_fss_cnt[i].type)
				{
				case CNT_TYPE_KIP:
					if (stock)
						continue;
					merge_kip_t *mkip1 = (merge_kip_t *)malloc(sizeof(merge_kip_t));
					mkip1->kip1 = content;
					list_append(&ctxt->kip1_list, &mkip1->link);
					DPRINTF("Loaded %s.kip1 from FSS0 (size %08X)\n", curr_fss_cnt[i].name, curr_fss_cnt[i].size);
					break;

				case CNT_TYPE_KRN:
					if (stock)
						continue;
					ctxt->kernel_size = curr_fss_cnt[i].size;
					ctxt->kernel = content;
					break;

				case CNT_TYPE_EXO:
					ctxt->secmon_size = curr_fss_cnt[i].size;
					ctxt->secmon = content;
					break;

				case CNT_TYPE_EXF:
					ctxt->exofatal_size = curr_fss_cnt[i].size;
					ctxt->exofatal = content;
					break;

				case CNT_TYPE_WBT:
					if (h_cfg.t210b01)
						continue;
					ctxt->warmboot_size = curr_fss_cnt[i].size;
					ctxt->warmboot = content;
					break;

				default:
					continue;
				}

				// Load content to launch context.
				f_lseek(&fp, curr_fss_cnt[i].offset);
				f_read(&fp, content, curr_fss_cnt[i].size, NULL);
			}
			else
			{
				// Load sept content directly to launch context.
				switch (curr_fss_cnt[i].type)
				{
				case CNT_TYPE_SP1:
					f_lseek(&fp, curr_fss_cnt[i].offset);
					f_read(&fp, sept_ctxt->sept_primary, curr_fss_cnt[i].size, NULL);
					break;
				case CNT_TYPE_SP2:
					if (!memcmp(curr_fss_cnt[i].name, (sept_ctxt->kb < KB_FIRMWARE_VERSION_810) ? "septsecondary00" : "septsecondary01", 15))
					{
						f_lseek(&fp, curr_fss_cnt[i].offset);
						f_read(&fp, sept_ctxt->sept_secondary, curr_fss_cnt[i].size, NULL);
						sept_used = 1;
						goto out;
					}
					break;
				default:
					break;
				}
			}
		}

out:
		gfx_printf("Done!\n");
		f_close(&fp);

		return (!sept_ctxt ? 1 : sept_used);
	}

fail:
	f_close(&fp);
	free(fss);

	return 0;
}

int load_sept_from_ffs0(fss0_sept_t *sept_ctxt)
{
	LIST_FOREACH_ENTRY(ini_kv_t, kv, &sept_ctxt->cfg_sec->kvs, link)
	{
		if (!strcmp("fss0", kv->key))
			return parse_fss(NULL, kv->val, sept_ctxt);
	}

	return 0;
}