/*
 *	Copyright (c) 2024 Scott Duensing, scott@kangaroopunch.com
 *
 *	Permission is hereby granted, free of charge, to any person obtaining a copy
 *	of this software and associated documentation files (the "Software"), to deal
 *	in the Software without restriction, including without limitation the rights
 *	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 *	copies of the Software, and to permit persons to whom the Software is
 *	furnished to do so, subject to the following conditions:
 *
 *	The above copyright notice and this permission notice shall be included in
 *	all copies or substantial portions of the Software.
 *
 *	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 *	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 *	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 *	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 *	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 *	SOFTWARE.
 */


#include <string.h>

#include "memory.h"
#include "story.h"
#include "state.h"

#include "zork1.h"


// The F256 has 512k of RAM.  We use everything except the lower 64k.
static uint8_t _RAM[1024 * (512 - 64)];


uint8_t memoryByte(uint16_t address) {
	return _RAM[address];
}


void memorySetByte(uint16_t address, uint8_t value) {
	_RAM[address] = value;
}


void memorySetWord(uint16_t address, uint16_t value) {
	_RAM[address]     = (value & 0xff00) << 8;   // MSB first.
	_RAM[address + 1] = value & 0x00ff;
}


uint32_t memoryUnpackAddress(uint16_t address, uint8_t type) {
	switch (storyVersion()) {
		case 1:
		case 2:
		case 3:
			return (uint32_t)address * 2;
		case 4:
		case 5:
			return (uint32_t)address * 4;
		case 6:
			if (type == MEMORY_ROUTINE) {
				return ((uint32_t)address * 4) + storyRoutinesOffset();
			} else {
				return ((uint32_t)address * 4) + storyStringsOffset();
			}
		case 8:
			return (uint32_t)address * 8;
	}

	return ((uint16_t)_RAM[address] << 8) | ((uint16_t)_RAM[address + 1]);
}


uint16_t memoryWord(uint16_t address) {
	return ((uint16_t)_RAM[address] << 8) | ((uint16_t)_RAM[address + 1]);
}


void memoryLoadStory(void) {
	// For now, we just copy an embedded Zork 1 into RAM.
	memcpy(_RAM, zork1, zork1_len);

	// Later, we probably want to see if the user has a memory expansion
	// installed.  If they do, we can use it and then use the lower memory
	// for graphics and sound.

	// Zero out all state data.
	memset(&__state, 0, sizeof(stateT));

	// Currently no status bar.
	POKE(STORY_FLAG_V3, PEEK(STORY_FLAG_V3) | STORY_FLAG_V3_STATUS_LINE_NOT_AVAILABLE);

	// Uncomment for status bar and window splitting.
	//POKE(STORY_FLAG_V3, PEEK(STORY_FLAG_V3) & ~STORY_FLAG_V3_STATUS_LINE_NOT_AVAILABLE);
	//POKE(STORY_FLAG_V3, PEEK(STORY_FLAG_V3) | STORY_FLAG_V3_SCREEN_SPLITTING);

	// V6+ this is the address of main(), not just a raw starting address.
	__state.pc = storyInitialPC();
	__state.sp = 0;
}