//
//  8088Tests.m
//  Clock SignalTests
//
//  Created by Thomas Harte on 13/09/2023.
//  Copyright © 2023 Thomas Harte. All rights reserved.
//

#import <XCTest/XCTest.h>

#include <array>
#include <cassert>

#include <iostream>
#include <sstream>
#include <fstream>

#include "NSData+dataWithContentsOfGZippedFile.h"

#include "../../../InstructionSets/x86/Decoder.hpp"

namespace {

// The tests themselves are not duplicated in this repository;
// provide their real path here.
constexpr char TestSuiteHome[] = "/Users/tharte/Projects/ProcessorTests/8088/v1";

}

@interface i8088Tests : XCTestCase
@end

@implementation i8088Tests

- (NSArray<NSString *> *)testFiles {
	NSString *path = [NSString stringWithUTF8String:TestSuiteHome];
	NSSet *allowList = [NSSet setWithArray:@[
	]];

	NSSet *ignoreList = nil;

	NSArray<NSString *> *files = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:path error:nil];
	files = [files filteredArrayUsingPredicate:[NSPredicate predicateWithBlock:^BOOL(NSString* evaluatedObject, NSDictionary<NSString *,id> *) {
		if(allowList.count && ![allowList containsObject:[evaluatedObject lastPathComponent]]) {
			return NO;
		}
		if([ignoreList containsObject:[evaluatedObject lastPathComponent]]) {
			return NO;
		}
		return [evaluatedObject hasSuffix:@"json.gz"];
	}]];

	NSMutableArray<NSString *> *fullPaths = [[NSMutableArray alloc] init];
	for(NSString *file in files) {
		[fullPaths addObject:[path stringByAppendingPathComponent:file]];
	}

	return [fullPaths sortedArrayUsingSelector:@selector(compare:)];
}

- (NSString *)toString:(const InstructionSet::x86::Instruction<false> &)instruction offsetLength:(int)offsetLength immediateLength:(int)immediateLength {
	const auto operation = to_string(instruction, InstructionSet::x86::Model::i8086, offsetLength, immediateLength);
	return [[NSString stringWithUTF8String:operation.c_str()] stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
}

- (bool)applyDecodingTest:(NSDictionary *)test file:(NSString *)file assert:(BOOL)assert {
	using Decoder = InstructionSet::x86::Decoder<InstructionSet::x86::Model::i8086>;
	Decoder decoder;

	// Build a vector of the instruction bytes; this makes manual step debugging easier.
	NSArray<NSNumber *> *encoding = test[@"bytes"];
	std::vector<uint8_t> data;
	data.reserve(encoding.count);
	for(NSNumber *number in encoding) {
		data.push_back([number intValue]);
	}
	auto hex_instruction = [&]() -> NSString * {
		NSMutableString *hexInstruction = [[NSMutableString alloc] init];
		for(uint8_t byte: data) {
			[hexInstruction appendFormat:@"%02x ", byte];
		}
		return hexInstruction;
	};

	const auto decoded = decoder.decode(data.data(), data.size());
	if(assert) {
		XCTAssert(
			decoded.first == [encoding count],
			"Wrong length of instruction decoded for %@ — decoded %d rather than %lu from %@; file %@",
				test[@"name"],
				decoded.first,
				(unsigned long)[encoding count],
				hex_instruction(),
				file
		);
	}
	if(decoded.first != [encoding count]) {
		return false;
	}

	// The decoder doesn't preserve the original offset length, which makes no functional difference but
	// does affect the way that offsets are printed in the test set.
	NSSet<NSString *> *decodings = [NSSet setWithObjects:
		[self toString:decoded.second offsetLength:4 immediateLength:4],
		[self toString:decoded.second offsetLength:2 immediateLength:4],
		[self toString:decoded.second offsetLength:0 immediateLength:4],
		[self toString:decoded.second offsetLength:4 immediateLength:2],
		[self toString:decoded.second offsetLength:2 immediateLength:2],
		[self toString:decoded.second offsetLength:0 immediateLength:2],
		nil];

	auto compare_decoding = [&](NSString *name) -> bool {
		return [decodings containsObject:name];
	};

	bool isEqual = compare_decoding(test[@"name"]);

	// Attempt clerical reconciliation:
	//
	// TEMPORARY HACK: the test set incorrectly states 'bp+si' whenever it means 'bp+di'.
	// Though it also uses 'bp+si' correctly when it means 'bp+si'. Until fixed, take
	// a pass on potential issues there.
	//
	// SEPARATELY: The test suite retains a distinction between SHL and SAL, which the decoder doesn't. So consider that
	// a potential point of difference.
	//
	// Also, the decoder treats INT3 and INT 3 as the same thing. So allow for a meshing of those.
	int adjustment = 7;
	while(!isEqual && adjustment) {
		NSString *alteredName = [test[@"name"] stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];

		if(adjustment & 4) {
			alteredName = [alteredName stringByReplacingOccurrencesOfString:@"bp+si" withString:@"bp+di"];
		}
		if(adjustment & 2) {
			alteredName = [alteredName stringByReplacingOccurrencesOfString:@"shl" withString:@"sal"];
		}
		if(adjustment & 1) {
			alteredName = [alteredName stringByReplacingOccurrencesOfString:@"int3" withString:@"int 03h"];
		}

		isEqual = compare_decoding(alteredName);
		--adjustment;
	}

	if(assert) {
		XCTAssert(
			isEqual,
			"%@ doesn't match %@ or similar, was %@ within %@",
				test[@"name"],
				[decodings anyObject],
				hex_instruction(),
				file
		);
	}

	return isEqual;
}

- (void)testDecoding {
	NSMutableSet<NSString *> *failures = [[NSMutableSet alloc] init];
	NSArray<NSString *> *testFiles = [self testFiles];

	for(NSString *file in testFiles) {
		NSData *data = [NSData dataWithContentsOfGZippedFile:file];
		NSArray<NSDictionary *> *testsInFile = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil];
		NSUInteger successes = 0;
		for(NSDictionary *test in testsInFile) {
			// A single failure per instruction is fine.
			if(![self applyDecodingTest:test file:file assert:YES]) {
				[failures addObject:file];

				// Attempt a second decoding, to provide a debugger hook.
				[self applyDecodingTest:test file:file assert:NO];

				break;
			}
			++successes;
		}
		if(successes != [testsInFile count]) {
			NSLog(@"Failed after %ld successes", successes);
		}
	}

	NSLog(@"%ld failures out of %ld tests: %@", failures.count, testFiles.count, [[failures allObjects] sortedArrayUsingSelector:@selector(caseInsensitiveCompare:)]);
}

@end