// can't use rustfmt here because it screws up the file.
#![cfg_attr(rustfmt, rustfmt_skip)]
use types::{FromRedisValue, ToRedisArgs, RedisResult, NumericBehavior};
use client::Client;
use connection::{Connection, ConnectionLike, Msg};
use cmd::{cmd, Cmd, Pipeline, Iter};


macro_rules! implement_commands {
    (
        $(
            $(#[$attr:meta])+
            fn $name:ident<$($tyargs:ident : $ty:ident),*>(
                $($argname:ident: $argty:ty),*) $body:block
        )*
    ) =>
    (
        /// Implements common redis commands for connection like objects.  This
        /// allows you to send commands straight to a connection or client.  It
        /// is also implemented for redis results of clients which makes for
        /// very convenient access in some basic cases.
        ///
        /// This allows you to use nicer syntax for some common operations.
        /// For instance this code:
        ///
        /// ```rust,no_run
        /// # fn do_something() -> redis::RedisResult<()> {
        /// let client = try!(redis::Client::open("redis://127.0.0.1/"));
        /// let con = try!(client.get_connection());
        /// redis::cmd("SET").arg("my_key").arg(42).execute(&con);
        /// assert_eq!(redis::cmd("GET").arg("my_key").query(&con), Ok(42));
        /// # Ok(()) }
        /// ```
        ///
        /// Will become this:
        ///
        /// ```rust,no_run
        /// # fn do_something() -> redis::RedisResult<()> {
        /// use redis::Commands;
        /// let client = try!(redis::Client::open("redis://127.0.0.1/"));
        /// let con = try!(client.get_connection());
        /// assert_eq!(con.get("my_key"), Ok(42));
        /// # Ok(()) }
        /// ```
        pub trait Commands : ConnectionLike+Sized {
            $(
                $(#[$attr])*
                #[inline]
                fn $name<$($tyargs: $ty,)* RV: FromRedisValue>(
                    &self $(, $argname: $argty)*) -> RedisResult<RV>
                    { ($body).query(self) }
            )*

            /// Incrementally iterate the keys space.
            #[inline]
            fn scan<RV: FromRedisValue>(&self) -> RedisResult<Iter<RV>> {
                cmd("SCAN").cursor_arg(0).iter(self)
            }

            /// Incrementally iterate the keys space for keys matching a pattern.
            #[inline]
            fn scan_match<P: ToRedisArgs, RV: FromRedisValue>(&self, pattern: P) -> RedisResult<Iter<RV>> {
                cmd("SCAN").cursor_arg(0).arg("MATCH").arg(pattern).iter(self)
            }

            /// Incrementally iterate hash fields and associated values.
            #[inline]
            fn hscan<K: ToRedisArgs, RV: FromRedisValue>(&self, key: K) -> RedisResult<Iter<RV>> {
                cmd("HSCAN").arg(key).cursor_arg(0).iter(self)
            }

            /// Incrementally iterate hash fields and associated values for
            /// field names matching a pattern.
            #[inline]
            fn hscan_match<K: ToRedisArgs, P: ToRedisArgs, RV: FromRedisValue>
                    (&self, key: K, pattern: P) -> RedisResult<Iter<RV>> {
                cmd("HSCAN").arg(key).cursor_arg(0).arg("MATCH").arg(pattern).iter(self)
            }

            /// Incrementally iterate set elements.
            #[inline]
            fn sscan<K: ToRedisArgs, RV: FromRedisValue>(&self, key: K) -> RedisResult<Iter<RV>> {
                cmd("SSCAN").arg(key).cursor_arg(0).iter(self)
            }

            /// Incrementally iterate set elements for elements matching a pattern.
            #[inline]
            fn sscan_match<K: ToRedisArgs, P: ToRedisArgs, RV: FromRedisValue>
                    (&self, key: K, pattern: P) -> RedisResult<Iter<RV>> {
                cmd("SSCAN").arg(key).cursor_arg(0).arg("MATCH").arg(pattern).iter(self)
            }

            /// Incrementally iterate sorted set elements.
            #[inline]
            fn zscan<K: ToRedisArgs, RV: FromRedisValue>(&self, key: K) -> RedisResult<Iter<RV>> {
                cmd("ZSCAN").arg(key).cursor_arg(0).iter(self)
            }

            /// Incrementally iterate sorted set elements for elements matching a pattern.
            #[inline]
            fn zscan_match<K: ToRedisArgs, P: ToRedisArgs, RV: FromRedisValue>
                    (&self, key: K, pattern: P) -> RedisResult<Iter<RV>> {
                cmd("ZSCAN").arg(key).cursor_arg(0).arg("MATCH").arg(pattern).iter(self)
            }
        }

        /// Implements common redis commands for pipelines.  Unlike the regular
        /// commands trait, this returns the pipeline rather than a result
        /// directly.  Other than that it works the same however.
        pub trait PipelineCommands {
            #[doc(hidden)]
            #[inline]
            fn perform(&mut self, con: &Cmd) -> &mut Self;

            $(
                $(#[$attr])*
                #[inline]
                fn $name<'a $(, $tyargs: $ty)*>(
                    &mut self $(, $argname: $argty)*) -> &mut Self
                    { self.perform($body) }
            )*
        }
    )
}

implement_commands! {
    // most common operations

    /// Get the value of a key.  If key is a vec this becomes an `MGET`.
    fn get<K: ToRedisArgs>(key: K) {
        cmd(if key.is_single_arg() { "GET" } else { "MGET" }).arg(key)
    }

    /// Gets all keys matching pattern
    fn keys<K: ToRedisArgs>(key: K) {
        cmd("KEYS").arg(key)
    }

    /// Set the string value of a key.
    fn set<K: ToRedisArgs, V: ToRedisArgs>(key: K, value: V) {
        cmd("SET").arg(key).arg(value)
    }

    /// Sets multiple keys to their values.
    fn set_multiple<K: ToRedisArgs, V: ToRedisArgs>(items: &[(K, V)]) {
        cmd("MSET").arg(items)
    }

    /// Set the value and expiration of a key.
    fn set_ex<K: ToRedisArgs, V: ToRedisArgs>(key: K, value: V, seconds: usize) {
        cmd("SETEX").arg(key).arg(seconds).arg(value)
    }

    /// Set the value of a key, only if the key does not exist
    fn set_nx<K: ToRedisArgs, V: ToRedisArgs>(key: K, value: V) {
        cmd("SETNX").arg(key).arg(value)
    }

    /// Sets multiple keys to their values failing if at least one already exists.
    fn mset_nx<K: ToRedisArgs, V: ToRedisArgs>(items: &[(K, V)]) {
        cmd("MSETNX").arg(items)
    }

    /// Set the string value of a key and return its old value.
    fn getset<K: ToRedisArgs, V: ToRedisArgs>(key: K, value: V) {
        cmd("GETSET").arg(key).arg(value)
    }

    /// Delete one or more keys.
    fn del<K: ToRedisArgs>(key: K) {
        cmd("DEL").arg(key)
    }

    /// Determine if a key exists.
    fn exists<K: ToRedisArgs>(key: K) {
        cmd("EXISTS").arg(key)
    }

    /// Set a key's time to live in seconds.
    fn expire<K: ToRedisArgs>(key: K, seconds: usize) {
        cmd("EXPIRE").arg(key).arg(seconds)
    }

    /// Set the expiration for a key as a UNIX timestamp.
    fn expire_at<K: ToRedisArgs>(key: K, ts: usize) {
        cmd("EXPIREAT").arg(key).arg(ts)
    }

    /// Set a key's time to live in milliseconds.
    fn pexpire<K: ToRedisArgs>(key: K, ms: usize) {
        cmd("PEXPIRE").arg(key).arg(ms)
    }

    /// Set the expiration for a key as a UNIX timestamp in milliseconds.
    fn pexpire_at<K: ToRedisArgs>(key: K, ts: usize) {
        cmd("PEXPIREAT").arg(key).arg(ts)
    }

    /// Remove the expiration from a key.
    fn persist<K: ToRedisArgs>(key: K) {
        cmd("PERSIST").arg(key)
    }

    /// Rename a key.
    fn rename<K: ToRedisArgs>(key: K, new_key: K) {
        cmd("RENAME").arg(key).arg(new_key)
    }

    /// Rename a key, only if the new key does not exist.
    fn rename_nx<K: ToRedisArgs>(key: K, new_key: K) {
        cmd("RENAMENX").arg(key).arg(new_key)
    }

    // common string operations

    /// Append a value to a key.
    fn append<K: ToRedisArgs, V: ToRedisArgs>(key: K, value: V) {
        cmd("APPEND").arg(key).arg(value)
    }

    /// Increment the numeric value of a key by the given amount.  This
    /// issues a `INCRBY` or `INCRBYFLOAT` depending on the type.
    fn incr<K: ToRedisArgs, V: ToRedisArgs>(key: K, delta: V) {
        cmd(if delta.describe_numeric_behavior() == NumericBehavior::NumberIsFloat {
            "INCRBYFLOAT"
        } else {
            "INCRBY"
        }).arg(key).arg(delta)
    }

    /// Sets or clears the bit at offset in the string value stored at key.
    fn setbit<K: ToRedisArgs>(key: K, offset: usize, value: bool) {
        cmd("SETBIT").arg(key).arg(offset).arg(if value {1} else {0})
    }

    /// Returns the bit value at offset in the string value stored at key.
    fn getbit<K: ToRedisArgs>(key: K, offset: usize) {
        cmd("GETBIT").arg(key).arg(offset)
    }

    /// Count set bits in a string.
    fn bitcount<K: ToRedisArgs>(key: K) {
        cmd("BITCOUNT").arg(key)
    }

    /// Count set bits in a string in a range.
    fn bitcount_range<K: ToRedisArgs>(key: K, start: usize, end: usize) {
        cmd("BITCOUNT").arg(key).arg(start).arg(end)
    }

    /// Perform a bitwise AND between multiple keys (containing string values)
    /// and store the result in the destination key.
    fn bit_and<K: ToRedisArgs>(dstkey: K, srckeys: K) {
        cmd("BITOP").arg("AND").arg(dstkey).arg(srckeys)
    }

    /// Perform a bitwise OR between multiple keys (containing string values)
    /// and store the result in the destination key.
    fn bit_or<K: ToRedisArgs>(dstkey: K, srckeys: K) {
        cmd("BITOP").arg("OR").arg(dstkey).arg(srckeys)
    }

    /// Perform a bitwise XOR between multiple keys (containing string values)
    /// and store the result in the destination key.
    fn bit_xor<K: ToRedisArgs>(dstkey: K, srckeys: K) {
        cmd("BITOP").arg("XOR").arg(dstkey).arg(srckeys)
    }

    /// Perform a bitwise NOT of the key (containing string values)
    /// and store the result in the destination key.
    fn bit_not<K: ToRedisArgs>(dstkey: K, srckey: K) {
        cmd("BITOP").arg("NOT").arg(dstkey).arg(srckey)
    }

    /// Get the length of the value stored in a key.
    fn strlen<K: ToRedisArgs>(key: K) {
        cmd("STRLEN").arg(key)
    }

    // hash operations

    /// Gets a single (or multiple) fields from a hash.
    fn hget<K: ToRedisArgs, F: ToRedisArgs>(key: K, field: F) {
        cmd(if field.is_single_arg() { "HGET" } else { "HMGET" }).arg(key).arg(field)
    }

    /// Deletes a single (or multiple) fields from a hash.
    fn hdel<K: ToRedisArgs, F: ToRedisArgs>(key: K, field: F) {
        cmd("HDEL").arg(key).arg(field)
    }

    /// Sets a single field in a hash.
    fn hset<K: ToRedisArgs, F: ToRedisArgs, V: ToRedisArgs>(key: K, field: F, value: V) {
        cmd("HSET").arg(key).arg(field).arg(value)
    }

    /// Sets a single field in a hash if it does not exist.
    fn hset_nx<K: ToRedisArgs, F: ToRedisArgs, V: ToRedisArgs>(key: K, field: F, value: V) {
        cmd("HSETNX").arg(key).arg(field).arg(value)
    }

    /// Sets a multiple fields in a hash.
    fn hset_multiple<K: ToRedisArgs, F: ToRedisArgs, V: ToRedisArgs>(key: K, items: &[(F, V)]) {
        cmd("HMSET").arg(key).arg(items)
    }

    /// Increments a value.
    fn hincr<K: ToRedisArgs, F: ToRedisArgs, D: ToRedisArgs>(key: K, field: F, delta: D) {
        cmd(if delta.describe_numeric_behavior() == NumericBehavior::NumberIsFloat {
            "HINCRBYFLOAT"
        } else {
            "HINCRBY"
        }).arg(key).arg(field).arg(delta)
    }

    /// Checks if a field in a hash exists.
    fn hexists<K: ToRedisArgs, F: ToRedisArgs>(key: K, field: F) {
        cmd("HEXISTS").arg(key).arg(field)
    }

    /// Gets all the keys in a hash.
    fn hkeys<K: ToRedisArgs>(key: K) {
        cmd("HKEYS").arg(key)
    }

    /// Gets all the values in a hash.
    fn hvals<K: ToRedisArgs>(key: K) {
        cmd("HVALS").arg(key)
    }

    /// Gets all the fields and values in a hash.
    fn hgetall<K: ToRedisArgs>(key: K) {
        cmd("HGETALL").arg(key)
    }

    /// Gets the length of a hash.
    fn hlen<K: ToRedisArgs>(key: K) {
        cmd("HLEN").arg(key)
    }

    // list operations

    /// Remove and get the first element in a list, or block until one is available.
    fn blpop<K: ToRedisArgs>(key: K, timeout: usize) {
        cmd("BLPOP").arg(key).arg(timeout)
    }

    /// Remove and get the last element in a list, or block until one is available.
    fn brpop<K: ToRedisArgs>(key: K, timeout: usize) {
        cmd("BRPOP").arg(key).arg(timeout)
    }

    /// Pop a value from a list, push it to another list and return it;
    /// or block until one is available.
    fn brpoplpush<K: ToRedisArgs>(srckey: K, dstkey: K, timeout: usize) {
        cmd("BRPOPLPUSH").arg(srckey).arg(dstkey).arg(timeout)
    }

    /// Get an element from a list by its index.
    fn lindex<K: ToRedisArgs>(key: K, index: isize) {
        cmd("LINDEX").arg(key).arg(index)
    }

    /// Insert an element before another element in a list.
    fn linsert_before<K: ToRedisArgs, P: ToRedisArgs, V: ToRedisArgs>(
            key: K, pivot: P, value: V) {
        cmd("LINSERT").arg(key).arg("BEFORE").arg(pivot).arg(value)
    }

    /// Insert an element after another element in a list.
    fn linsert_after<K: ToRedisArgs, P: ToRedisArgs, V: ToRedisArgs>(
            key: K, pivot: P, value: V) {
        cmd("LINSERT").arg(key).arg("AFTER").arg(pivot).arg(value)
    }

    /// Returns the length of the list stored at key.
    fn llen<K: ToRedisArgs>(key: K) {
        cmd("LLEN").arg(key)
    }

    /// Removes and returns the first element of the list stored at key.
    fn lpop<K: ToRedisArgs>(key: K) {
        cmd("LPOP").arg(key)
    }

    /// Insert all the specified values at the head of the list stored at key.
    fn lpush<K: ToRedisArgs, V: ToRedisArgs>(key: K, value: V) {
        cmd("LPUSH").arg(key).arg(value)
    }

    /// Inserts a value at the head of the list stored at key, only if key
    /// already exists and holds a list.
    fn lpush_exists<K: ToRedisArgs, V: ToRedisArgs>(key: K, value: V) {
        cmd("LPUSHX").arg(key).arg(value)
    }

    /// Returns the specified elements of the list stored at key.
    fn lrange<K: ToRedisArgs>(key: K, start: isize, stop: isize) {
        cmd("LRANGE").arg(key).arg(start).arg(stop)
    }

    /// Removes the first count occurrences of elements equal to value
    /// from the list stored at key.
    fn lrem<K: ToRedisArgs, V: ToRedisArgs>(key: K, count: isize, value: V) {
        cmd("LREM").arg(key).arg(count).arg(value)
    }

    /// Trim an existing list so that it will contain only the specified
    /// range of elements specified.
    fn ltrim<K: ToRedisArgs>(key: K, start: isize, stop: isize) {
        cmd("LTRIM").arg(key).arg(start).arg(stop)
    }

    /// Sets the list element at index to value
    fn lset<K: ToRedisArgs, V: ToRedisArgs>(key: K, index: isize, value: V) {
        cmd("LSET").arg(key).arg(index).arg(value)
    }

    /// Removes and returns the last element of the list stored at key.
    fn rpop<K: ToRedisArgs>(key: K) {
        cmd("RPOP").arg(key)
    }

    /// Pop a value from a list, push it to another list and return it.
    fn rpoplpush<K: ToRedisArgs>(key: K, dstkey: K) {
        cmd("RPOPLPUSH").arg(key).arg(dstkey)
    }

    /// Insert all the specified values at the tail of the list stored at key.
    fn rpush<K: ToRedisArgs, V: ToRedisArgs>(key: K, value: V) {
        cmd("RPUSH").arg(key).arg(value)
    }

    /// Inserts value at the tail of the list stored at key, only if key
    /// already exists and holds a list.
    fn rpush_exists<K: ToRedisArgs, V: ToRedisArgs>(key: K, value: V) {
        cmd("RPUSHX").arg(key).arg(value)
    }

    // set commands

    /// Add one or more members to a set.
    fn sadd<K: ToRedisArgs, M: ToRedisArgs>(key: K, member: M) {
        cmd("SADD").arg(key).arg(member)
    }

    /// Get the number of members in a set.
    fn scard<K: ToRedisArgs>(key: K) {
        cmd("SCARD").arg(key)
    }

    /// Subtract multiple sets.
    fn sdiff<K: ToRedisArgs>(keys: K) {
        cmd("SDIFF").arg(keys)
    }

    /// Subtract multiple sets and store the resulting set in a key.
    fn sdiffstore<K: ToRedisArgs>(dstkey: K, keys: K) {
        cmd("SDIFFSTORE").arg(dstkey).arg(keys)
    }

    /// Intersect multiple sets.
    fn sinter<K: ToRedisArgs>(keys: K) {
        cmd("SINTER").arg(keys)
    }

    /// Intersect multiple sets and store the resulting set in a key.
    fn sdinterstore<K: ToRedisArgs>(dstkey: K, keys: K) {
        cmd("SINTERSTORE").arg(dstkey).arg(keys)
    }

    /// Determine if a given value is a member of a set.
    fn sismember<K: ToRedisArgs, M: ToRedisArgs>(key: K, member: M) {
        cmd("SISMEMBER").arg(key).arg(member)
    }

    /// Get all the members in a set.
    fn smembers<K: ToRedisArgs>(key: K) {
        cmd("SMEMBERS").arg(key)
    }

    /// Move a member from one set to another.
    fn smove<K: ToRedisArgs, M: ToRedisArgs>(srckey: K, dstkey: K, member: M) {
        cmd("SMOVE").arg(srckey).arg(dstkey).arg(member)
    }

    /// Remove and return a random member from a set.
    fn spop<K: ToRedisArgs>(key: K) {
        cmd("SPOP").arg(key)
    }

    /// Get one random member from a set.
    fn srandmember<K: ToRedisArgs>(key: K) {
        cmd("SRANDMEMBER").arg(key)
    }

    /// Get multiple random members from a set.
    fn srandmember_multiple<K: ToRedisArgs>(key: K, count: usize) {
        cmd("SRANDMEMBER").arg(key).arg(count)
    }

    /// Remove one or more members from a set.
    fn srem<K: ToRedisArgs, M: ToRedisArgs>(key: K, member: M) {
        cmd("SREM").arg(key).arg(member)
    }

    /// Add multiple sets.
    fn sunion<K: ToRedisArgs>(keys: K) {
        cmd("SUNION").arg(keys)
    }

    /// Add multiple sets and store the resulting set in a key.
    fn sunionstore<K: ToRedisArgs>(dstkey: K, keys: K) {
        cmd("SUNIONSTORE").arg(dstkey).arg(keys)
    }

    // sorted set commands

    /// Add one member to a sorted set, or update its score if it already exists.
    fn zadd<K: ToRedisArgs, S: ToRedisArgs, M: ToRedisArgs>(key: K, member: M, score: S) {
        cmd("ZADD").arg(key).arg(score).arg(member)
    }

    /// Add multiple members to a sorted set, or update its score if it already exists.
    fn zadd_multiple<K: ToRedisArgs, S: ToRedisArgs, M: ToRedisArgs>(key: K, items: &[(S, M)]) {
        cmd("ZADD").arg(key).arg(items)
    }

    /// Get the number of members in a sorted set.
    fn zcard<K: ToRedisArgs>(key: K) {
        cmd("ZCARD").arg(key)
    }

    /// Count the members in a sorted set with scores within the given values.
    fn zcount<K: ToRedisArgs, M: ToRedisArgs, MM: ToRedisArgs>(key: K, min: M, max: MM) {
        cmd("ZCOUNT").arg(key).arg(min).arg(max)
    }

    /// Increments the member in a sorted set at key by delta.
    /// If the member does not exist, it is added with delta as its score.
    fn zincr<K: ToRedisArgs, M: ToRedisArgs, D: ToRedisArgs>(key: K, member: M, delta: D) {
        cmd("ZINCRBY").arg(key).arg(delta).arg(member)
    }

    /// Intersect multiple sorted sets and store the resulting sorted set in
    /// a new key using SUM as aggregation function.
    fn zinterstore<K: ToRedisArgs>(dstkey: K, keys: &[K]) {
        cmd("ZINTERSTORE").arg(dstkey).arg(keys.len()).arg(keys)
    }

    /// Intersect multiple sorted sets and store the resulting sorted set in
    /// a new key using MIN as aggregation function.
    fn zinterstore_min<K: ToRedisArgs>(dstkey: K, keys: &[K]) {
        cmd("ZINTERSTORE").arg(dstkey).arg(keys.len()).arg(keys).arg("AGGREGATE").arg("MIN")
    }

    /// Intersect multiple sorted sets and store the resulting sorted set in
    /// a new key using MAX as aggregation function.
    fn zinterstore_max<K: ToRedisArgs>(dstkey: K, keys: &[K]) {
        cmd("ZINTERSTORE").arg(dstkey).arg(keys.len()).arg(keys).arg("AGGREGATE").arg("MAX")
    }

    /// Count the number of members in a sorted set between a given lexicographical range.
    fn zlexcount<K: ToRedisArgs, L: ToRedisArgs>(key: K, min: L, max: L) {
        cmd("ZLEXCOUNT").arg(key).arg(min).arg(max)
    }

    /// Return a range of members in a sorted set, by index
    fn zrange<K: ToRedisArgs>(key: K, start: isize, stop: isize) {
        cmd("ZRANGE").arg(key).arg(start).arg(stop)
    }

    /// Return a range of members in a sorted set, by index with scores.
    fn zrange_withscores<K: ToRedisArgs>(key: K, start: isize, stop: isize) {
        cmd("ZRANGE").arg(key).arg(start).arg(stop).arg("WITHSCORES")
    }

    /// Return a range of members in a sorted set, by lexicographical range.
    fn zrangebylex<K: ToRedisArgs, M: ToRedisArgs, MM: ToRedisArgs>(key: K, min: M, max: MM) {
        cmd("ZRANGEBYLEX").arg(key).arg(min).arg(max)
    }

    /// Return a range of members in a sorted set, by lexicographical
    /// range with offset and limit.
    fn zrangebylex_limit<K: ToRedisArgs, M: ToRedisArgs, MM: ToRedisArgs>(
            key: K, min: M, max: MM, offset: isize, count: isize) {
        cmd("ZRANGEBYLEX").arg(key).arg(min).arg(max).arg("LIMIT").arg(offset).arg(count)
    }

    /// Return a range of members in a sorted set, by lexicographical range.
    fn zrevrangebylex<K: ToRedisArgs, MM: ToRedisArgs, M: ToRedisArgs>(key: K, max: MM, min: M) {
        cmd("ZREVRANGEBYLEX").arg(key).arg(max).arg(min)
    }

    /// Return a range of members in a sorted set, by lexicographical
    /// range with offset and limit.
    fn zrevrangebylex_limit<K: ToRedisArgs, MM: ToRedisArgs, M: ToRedisArgs>(
            key: K, max: MM, min: M, offset: isize, count: isize) {
        cmd("ZREVRANGEBYLEX").arg(key).arg(max).arg(min).arg("LIMIT").arg(offset).arg(count)
    }

    /// Return a range of members in a sorted set, by score.
    fn zrangebyscore<K: ToRedisArgs, M: ToRedisArgs, MM: ToRedisArgs>(key: K, min: M, max: MM) {
        cmd("ZRANGEBYSCORE").arg(key).arg(min).arg(max)
    }

    /// Return a range of members in a sorted set, by score with scores.
    fn zrangebyscore_withscores<K: ToRedisArgs, M: ToRedisArgs, MM: ToRedisArgs>(key: K, min: M, max: MM) {
        cmd("ZRANGEBYSCORE").arg(key).arg(min).arg(max).arg("WITHSCORES")
    }

    /// Return a range of members in a sorted set, by score with limit.
    fn zrangebyscore_limit<K: ToRedisArgs, M: ToRedisArgs, MM: ToRedisArgs>
            (key: K, min: M, max: MM, offset: isize, count: isize) {
        cmd("ZRANGEBYSCORE").arg(key).arg(min).arg(max).arg("LIMIT").arg(offset).arg(count)
    }

    /// Return a range of members in a sorted set, by score with limit with scores.
    fn zrangebyscore_limit_withscores<K: ToRedisArgs, M: ToRedisArgs, MM: ToRedisArgs>
            (key: K, min: M, max: MM, offset: isize, count: isize) {
        cmd("ZRANGEBYSCORE").arg(key).arg(min).arg(max).arg("WITHSCORES")
            .arg("LIMIT").arg(offset).arg(count)
    }

    /// Determine the index of a member in a sorted set.
    fn zrank<K: ToRedisArgs, M: ToRedisArgs>(key: K, member: M) {
        cmd("ZRANK").arg(key).arg(member)
    }

    /// Remove one or more members from a sorted set.
    fn zrem<K: ToRedisArgs, M: ToRedisArgs>(key: K, members: M) {
        cmd("ZREM").arg(key).arg(members)
    }

    /// Remove all members in a sorted set between the given lexicographical range.
    fn zrembylex<K: ToRedisArgs, M: ToRedisArgs, MM: ToRedisArgs>(key: K, min: M, max: MM) {
        cmd("ZREMBYLEX").arg(key).arg(min).arg(max)
    }

    /// Remove all members in a sorted set within the given indexes.
    fn zrembyrank<K: ToRedisArgs>(key: K, start: isize, stop: isize) {
        cmd("ZREMBYRANK").arg(key).arg(start).arg(stop)
    }

    /// Remove all members in a sorted set within the given scores.
    fn zrembyscore<K: ToRedisArgs, M: ToRedisArgs, MM: ToRedisArgs>(key: K, min: M, max: MM) {
        cmd("ZREMRANGEBYSCORE").arg(key).arg(min).arg(max)
    }

    /// Return a range of members in a sorted set, by index, with scores
    /// ordered from high to low.
    fn zrevrange<K: ToRedisArgs>(key: K, start: isize, stop: isize) {
        cmd("ZREVRANGE").arg(key).arg(start).arg(stop)
    }

    /// Return a range of members in a sorted set, by index, with scores
    /// ordered from high to low.
    fn zrevrange_withscores<K: ToRedisArgs>(key: K, start: isize, stop: isize) {
        cmd("ZREVRANGE").arg(key).arg(start).arg(stop).arg("WITHSCORES")
    }

    /// Return a range of members in a sorted set, by score.
    fn zrevrangebyscore<K: ToRedisArgs, MM: ToRedisArgs, M: ToRedisArgs>(key: K, max: MM, min: M) {
        cmd("ZREVRANGEBYSCORE").arg(key).arg(max).arg(min)
    }

    /// Return a range of members in a sorted set, by score with scores.
    fn zrevrangebyscore_withscores<K: ToRedisArgs, MM: ToRedisArgs, M: ToRedisArgs>(key: K, max: MM, min: M) {
        cmd("ZREVRANGEBYSCORE").arg(key).arg(max).arg(min).arg("WITHSCORES")
    }

    /// Return a range of members in a sorted set, by score with limit.
    fn zrevrangebyscore_limit<K: ToRedisArgs, MM: ToRedisArgs, M: ToRedisArgs>
            (key: K, max: MM, min: M, offset: isize, count: isize) {
        cmd("ZREVRANGEBYSCORE").arg(key).arg(max).arg(min).arg("LIMIT").arg(offset).arg(count)
    }

    /// Return a range of members in a sorted set, by score with limit with scores.
    fn zrevrangebyscore_limit_withscores<K: ToRedisArgs, MM: ToRedisArgs, M: ToRedisArgs>
            (key: K, max: MM, min: M, offset: isize, count: isize) {
        cmd("ZREVRANGEBYSCORE").arg(key).arg(max).arg(min).arg("WITHSCORES")
            .arg("LIMIT").arg(offset).arg(count)
    }

    /// Determine the index of a member in a sorted set, with scores ordered from high to low.
    fn zrevrank<K: ToRedisArgs, M: ToRedisArgs>(key: K, member: M) {
        cmd("ZREVRANK").arg(key).arg(member)
    }

    /// Get the score associated with the given member in a sorted set.
    fn zscore<K: ToRedisArgs, M: ToRedisArgs>(key: K, member: M) {
        cmd("ZSCORE").arg(key).arg(member)
    }

    /// Unions multiple sorted sets and store the resulting sorted set in
    /// a new key using SUM as aggregation function.
    fn zunionstore<K: ToRedisArgs>(dstkey: K, keys: &[K]) {
        cmd("ZUNIONSTORE").arg(dstkey).arg(keys.len()).arg(keys)
    }

    /// Unions multiple sorted sets and store the resulting sorted set in
    /// a new key using MIN as aggregation function.
    fn zunionstore_min<K: ToRedisArgs>(dstkey: K, keys: &[K]) {
        cmd("ZUNIONSTORE").arg(dstkey).arg(keys.len()).arg(keys).arg("AGGREGATE").arg("MIN")
    }

    /// Unions multiple sorted sets and store the resulting sorted set in
    /// a new key using MAX as aggregation function.
    fn zunionstore_max<K: ToRedisArgs>(dstkey: K, keys: &[K]) {
        cmd("ZUNIONSTORE").arg(dstkey).arg(keys.len()).arg(keys).arg("AGGREGATE").arg("MAX")
    }

    // hyperloglog commands

    /// Adds the specified elements to the specified HyperLogLog.
    fn pfadd<K: ToRedisArgs, E: ToRedisArgs>(key: K, element: E) {
        cmd("PFADD").arg(key).arg(element)
    }

    /// Return the approximated cardinality of the set(s) observed by the
    /// HyperLogLog at key(s).
    fn pfcount<K: ToRedisArgs>(key: K) {
        cmd("PFCOUNT").arg(key)
    }

    /// Merge N different HyperLogLogs into a single one.
    fn pfmerge<K: ToRedisArgs>(dstkey: K, srckeys: K) {
        cmd("PFMERGE").arg(dstkey).arg(srckeys)
    }

    /// Posts a message to the given channel.
    fn publish<K: ToRedisArgs, E: ToRedisArgs>(channel: K, message: E) {
        cmd("PUBLISH").arg(channel).arg(message)
    }
}

/// Allows pubsub callbacks to stop receiving messages.
///
/// Arbitrary data may be returned from `Break`.
pub enum ControlFlow<U> {
    Continue,
    Break(U),
}

/// The PubSub trait allows subscribing to one or more channels
/// and receiving a callback whenever a message arrives.
///
/// Each method handles subscribing to the list of keys, waiting for
/// messages, and unsubscribing from the same list of channels once
/// a ControlFlow::Break is encountered.
///
/// Once (p)subscribe returns Ok(U), the connection is again safe to use
/// for calling other methods.
///
/// # Examples
///
/// ```rust,no_run
/// # fn do_something() -> redis::RedisResult<()> {
/// use redis::{PubSubCommands, ControlFlow};
/// let client = redis::Client::open("redis://127.0.0.1/")?;
/// let mut con = client.get_connection()?;
/// let mut count = 0;
/// con.subscribe(&["foo"], |msg| {
///     // do something with message
///     assert_eq!(msg.get_channel(), Ok(String::from("foo")));
///
///     // increment messages seen counter
///     count += 1;
///     match count {
///         // stop after receiving 10 messages
///         10 => ControlFlow::Break(()),
///         _ => ControlFlow::Continue,
///     }
/// });
/// # Ok(()) }
/// ```
// TODO In the future, it would be nice to implement Try such that `?` will work
//      within the closure.
pub trait PubSubCommands: Sized {
    /// Subscribe to a list of channels using SUBSCRIBE and run the provided
    /// closure for each message received.
    ///
    /// For every `Msg` passed to the provided closure, either
    /// `ControlFlow::Break` or `ControlFlow::Continue` must be returned. This
    /// method will not return until `ControlFlow::Break` is observed.
    fn subscribe<'a, C, F, U>(&mut self, _: C, _: F) -> RedisResult<U>
        where F: FnMut(Msg) -> ControlFlow<U>,
              C: ToRedisArgs;

    /// Subscribe to a list of channels using PSUBSCRIBE and run the provided
    /// closure for each message received.
    ///
    /// For every `Msg` passed to the provided closure, either
    /// `ControlFlow::Break` or `ControlFlow::Continue` must be returned. This
    /// method will not return until `ControlFlow::Break` is observed.
    fn psubscribe<'a, P, F, U>(&mut self, _: P, _: F) -> RedisResult<U>
        where F: FnMut(Msg) -> ControlFlow<U>,
              P: ToRedisArgs;
}

impl Commands for Connection {}
impl Commands for Client {}

impl PubSubCommands for Connection {
    fn subscribe<'a, C, F, U>(&mut self, channels: C, mut func: F) -> RedisResult<U>
        where F: FnMut(Msg) -> ControlFlow<U>,
              C: ToRedisArgs
    {
        let mut pubsub = self.as_pubsub();
        pubsub.subscribe(channels)?;

        loop {
            let msg = pubsub.get_message()?;
            match func(msg) {
                ControlFlow::Continue => continue,
                ControlFlow::Break(value) => return Ok(value),
            }
        }
    }

    fn psubscribe<'a, P, F, U>(&mut self, patterns: P, mut func: F) -> RedisResult<U>
        where F: FnMut(Msg) -> ControlFlow<U>,
              P: ToRedisArgs
    {
        let mut pubsub = self.as_pubsub();
        pubsub.psubscribe(patterns)?;

        loop {
            let msg = pubsub.get_message()?;
            match func(msg) {
                ControlFlow::Continue => continue,
                ControlFlow::Break(value) => return Ok(value),
            }
        };
    }
}

impl PipelineCommands for Pipeline {
    fn perform(&mut self, cmd: &Cmd) -> &mut Pipeline {
        self.add_command(cmd)
    }
}