#import "ARTTokenParams+Private.h"

#import <CommonCrypto/CommonDigest.h>
#import <CommonCrypto/CommonHMAC.h>

#import "ARTDefault.h"
#import "ARTEncoder.h"
#import "ARTTokenRequest.h"

@implementation ARTTokenParams

- (instancetype)init {
    return [self initWithClientId:nil nonce:nil];
}

- (instancetype)initWithClientId:(NSString *)clientId {
    return [self initWithClientId:clientId nonce:nil];
}

- (instancetype)initWithClientId:(NSString *)clientId nonce:(NSString *)nonce {
    if (self = [super init]) {
        _timestamp = nil;
        _capability = nil; // capabilities of the underlying key
        _clientId = clientId;
        _nonce = nonce;
    }
    return self;
}

- (instancetype)initWithOptions:(ARTClientOptions *)options {
    self = [self initWithClientId:options.clientId];
    if (options.defaultTokenParams) {
        if (options.defaultTokenParams.ttl != nil) _ttl = options.defaultTokenParams.ttl;
        if (options.defaultTokenParams.capability) _capability = options.defaultTokenParams.capability;
    }
    return self;
}

- (instancetype)initWithTokenParams:(ARTTokenParams *)tokenParams {
    self = [self initWithClientId:tokenParams.clientId];
    self.timestamp = nil;
    self.ttl = tokenParams.ttl;
    self.capability = tokenParams.capability;
    return self;
}

- (NSString *)description {
    return [NSString stringWithFormat: @"ARTTokenParams: ttl=%@ capability=%@ timestamp=%@",
            self.ttl, self.capability, self.timestamp];
}

- (id)copyWithZone:(NSZone *)zone {
    ARTTokenParams *token = [[[self class] allocWithZone:zone] initWithClientId:_clientId nonce:_nonce];

    token.ttl = _ttl;
    token.capability = _capability;
    token.timestamp = _timestamp;

    return token;
}

- (NSMutableArray *)toArray {
    NSMutableArray *params = [[NSMutableArray alloc] init];
    
    if (self.clientId)
        [params addObject:[NSURLQueryItem queryItemWithName:@"clientId" value:self.clientId]];
    if (self.ttl != nil)
        [params addObject:[NSURLQueryItem queryItemWithName:@"ttl" value:[NSString stringWithFormat:@"%@", self.ttl]]];
    if (self.capability)
        [params addObject:[NSURLQueryItem queryItemWithName:@"capability" value:self.capability]];
    if (self.timestamp)
        [params addObject:[NSURLQueryItem queryItemWithName:@"timestamp" value:[NSString stringWithFormat:@"%llu", dateToMilliseconds(self.timestamp)]]];
    
    return params;
}

- (NSMutableDictionary<NSString *, NSString *> *)toDictionary {
    NSMutableDictionary<NSString *, NSString *> *const params = [NSMutableDictionary new];
    
    if (self.clientId)
        params[@"clientId"] = self.clientId;
    if (self.ttl != nil)
        params[@"ttl"] = [NSString stringWithFormat:@"%@", self.ttl];
    if (self.capability)
        params[@"capability"] = self.capability;
    if (self.timestamp)
        params[@"timestamp"] = [NSString stringWithFormat:@"%llu", dateToMilliseconds(self.timestamp)];
    
    return params;
}

- (NSArray *)toArrayWithUnion:(NSArray *)items {
    NSMutableArray *tokenParams = [self toArray];
    BOOL add = YES;
    
    for (NSURLQueryItem *item in items) {
        for (NSURLQueryItem *param in tokenParams) {
            // Check if exist
            if ([param.name isEqualToString:item.name]) {
                add = NO;
                break;
            }
        }
        if (add) {
            [tokenParams addObject:item];
        }
        add = YES;
    }
    
    return tokenParams;
}

- (NSStringDictionary *)toDictionaryWithUnion:(NSArray<NSURLQueryItem *> *const)items {
    NSMutableDictionary<NSString *, NSString *> *const tokenParams = [self toDictionary];
    BOOL add = YES;
    
    for (NSURLQueryItem *item in items) {
        for (NSString *key in tokenParams.allKeys) {
            // Check if exist
            if ([key isEqualToString:item.name]) {
                add = NO;
                break;
            }
        }
        if (add) {
            tokenParams[item.name] = item.value;
        }
        add = YES;
    }
    
    return [tokenParams copy]; // immutable
}

static NSString *hmacForDataAndKey(NSData *data, NSData *key) {
    const void *cKey = [key bytes];
    const void *cData = [data bytes];
    size_t keyLen = [key length];
    size_t dataLen = [data length];
    
    unsigned char hmac[CC_SHA256_DIGEST_LENGTH];
    
    CCHmac(kCCHmacAlgSHA256, cKey, keyLen, cData, dataLen, hmac);
    NSData *mac = [[NSData alloc] initWithBytes:hmac length:sizeof(hmac)];
    NSString *str = [mac base64EncodedStringWithOptions:0];
    return str;
}

- (ARTTokenRequest *)sign:(NSString *)key {
    return [self sign:key withNonce:self.nonce ? self.nonce : generateNonce()];
}

- (ARTTokenRequest *)sign:(NSString *)key withNonce:(NSString *)nonce {
    NSArray *keyComponents = decomposeKey(key);
    NSString *keyName = keyComponents[0];
    NSString *keySecret = keyComponents[1];
    NSString *capability = self.capability ? self.capability : @"";
    NSString *clientId = self.clientId ? self.clientId : @"";
    NSString *ttl = self.ttl != nil ? [NSString stringWithFormat:@"%lld", timeIntervalToMilliseconds([self.ttl doubleValue])] : @"";

    NSString *signText = [NSString stringWithFormat:@"%@\n%@\n%@\n%@\n%lld\n%@\n", keyName, ttl, capability, clientId, dateToMilliseconds(self.timestamp), nonce];
    NSString *mac = hmacForDataAndKey([signText dataUsingEncoding:NSUTF8StringEncoding], [keySecret dataUsingEncoding:NSUTF8StringEncoding]);

    return [[ARTTokenRequest alloc] initWithTokenParams:self keyName:keyName nonce:nonce mac:mac];
}

@end