//! Traits dealing with Postgres data types

extern mod extra;

use extra::time::Timespec;
use extra::json;
use extra::json::Json;
use extra::uuid::Uuid;
use std::hashmap::HashMap;
use std::io::Decorator;
use std::io::mem::{MemWriter, BufReader};
use std::mem;
use std::str;
use std::vec;

use self::array::{Array, ArrayBase, DimensionInfo};
use self::range::{RangeBound, Inclusive, Exclusive, Range};

pub mod array;
pub mod range;

/// A Postgres OID
pub type Oid = i32;

// Values from pg_type.h
static BOOLOID: Oid = 16;
static BYTEAOID: Oid = 17;
static CHAROID: Oid = 18;
static INT8OID: Oid = 20;
static INT2OID: Oid = 21;
static INT4OID: Oid = 23;
static TEXTOID: Oid = 25;
static JSONOID: Oid = 114;
static FLOAT4OID: Oid = 700;
static FLOAT8OID: Oid = 701;
static BOOLARRAYOID: Oid = 1000;
static BYTEAARRAYOID: Oid = 1001;
static CHARARRAYOID: Oid = 1002;
static INT2ARRAYOID: Oid = 1005;
static INT4ARRAYOID: Oid = 1007;
static TEXTARRAYOID: Oid = 1009;
static BPCHARARRAYOID: Oid = 1014;
static INT8ARRAYOID: Oid = 1016;
static FLOAT4ARRAYOID: Oid = 1021;
static FLAOT8ARRAYOID: Oid = 1022;
static BPCHAROID: Oid = 1042;
static VARCHAROID: Oid = 1043;
static TIMESTAMPOID: Oid = 1114;
static TIMESTAMPZOID: Oid = 1184;
static UUIDOID: Oid = 2950;
static INT4RANGEOID: Oid = 3904;
static TSRANGEOID: Oid = 3908;
static TSTZRANGEOID: Oid = 3910;
static INT8RANGEOID: Oid = 3926;

static USEC_PER_SEC: i64 = 1_000_000;
static NSEC_PER_USEC: i64 = 1_000;

// Number of seconds from 1970-01-01 to 2000-01-01
static TIME_SEC_CONVERSION: i64 = 946684800;

static RANGE_UPPER_UNBOUNDED: i8 = 0b0001_0000;
static RANGE_LOWER_UNBOUNDED: i8 = 0b0000_1000;
static RANGE_UPPER_INCLUSIVE: i8 = 0b0000_0100;
static RANGE_LOWER_INCLUSIVE: i8 = 0b0000_0010;
static RANGE_EMPTY: i8           = 0b0000_0001;

macro_rules! make_postgres_type(
    ($($doc:attr $variant:ident => $oid:ident $(member $member:ident)*),+) => (
        /// A Postgres type
        #[deriving(Eq)]
        #[allow(missing_doc)] // FIXME mozilla/rust#10853
        pub enum PostgresType {
            $(
                $doc
                $variant,
            )+
            /// An unknown type
            PgUnknownType {
                /// The name of the type
                name: ~str,
                /// The OID of the type
                oid: Oid
            }
        }

        impl PostgresType {
            #[doc(hidden)]
            pub fn from_oid(oid: Oid) -> PostgresType {
                match oid {
                    $($oid => $variant,)+
                    // We have to load an empty string now, it'll get filled in later
                    oid => PgUnknownType { name: ~"", oid: oid }
                }
            }

            #[doc(hidden)]
            pub fn to_oid(&self) -> Oid {
                match *self {
                    $($variant => $oid,)+
                    PgUnknownType { oid, .. } => oid
                }
            }

            fn member_type(&self) -> PostgresType {
                match *self {
                    $(
                        $($variant => $member,)*
                    )+
                    _ => unreachable!()
                }
            }

            /// Returns the wire format needed for the value of `self`.
            pub fn result_format(&self) -> Format {
                match *self {
                    PgUnknownType { name: ~"hstore", .. } => Binary,
                    PgUnknownType { .. } => Text,
                    _ => Binary
                }
            }
        }
    )
)

make_postgres_type!(
    #[doc="BOOL"]
    PgBool => BOOLOID,
    #[doc="BYTEA"]
    PgByteA => BYTEAOID,
    #[doc="\"char\""]
    PgChar => CHAROID,
    #[doc="INT8/BIGINT"]
    PgInt8 => INT8OID,
    #[doc="INT2/SMALLINT"]
    PgInt2 => INT2OID,
    #[doc="INT4/INT"]
    PgInt4 => INT4OID,
    #[doc="TEXT"]
    PgText => TEXTOID,
    #[doc="JSON"]
    PgJson => JSONOID,
    #[doc="FLOAT4/REAL"]
    PgFloat4 => FLOAT4OID,
    #[doc="FLOAT8/DOUBLE PRECISION"]
    PgFloat8 => FLOAT8OID,
    #[doc="BOOL[]"]
    PgBoolArray => BOOLARRAYOID member PgBool,
    #[doc="BYTEA[]"]
    PgByteAArray => BYTEAARRAYOID member PgByteA,
    #[doc="\"char\"[]"]
    PgCharArray => CHARARRAYOID member PgChar,
    #[doc="INT2[]"]
    PgInt2Array => INT2ARRAYOID member PgInt2,
    #[doc="INT4[]"]
    PgInt4Array => INT4ARRAYOID member PgInt4,
    #[doc="TEXT[]"]
    PgTextArray => TEXTARRAYOID member PgText,
    #[doc="CHAR(n)[]"]
    PgCharNArray => BPCHARARRAYOID member PgCharN,
    #[doc="INT8[]"]
    PgInt8Array => INT8ARRAYOID member PgInt8,
    #[doc="FLOAT4[]"]
    PgFloat4Array => FLOAT4ARRAYOID member PgFloat4,
    #[doc="FLOAT8[]"]
    PgFloat8Array => FLAOT8ARRAYOID member PgFloat8,
    #[doc="TIMESTAMP"]
    PgTimestamp => TIMESTAMPOID,
    #[doc="TIMESTAMP WITH TIME ZONE"]
    PgTimestampZ => TIMESTAMPZOID,
    #[doc="CHAR(n)/CHARACTER(n)"]
    PgCharN => BPCHAROID,
    #[doc="VARCHAR/CHARACTER VARYING"]
    PgVarchar => VARCHAROID,
    #[doc="UUID"]
    PgUuid => UUIDOID,
    #[doc="INT4RANGE"]
    PgInt4Range => INT4RANGEOID,
    #[doc="INT8RANGE"]
    PgInt8Range => INT8RANGEOID,
    #[doc="TSRANGE"]
    PgTsRange => TSRANGEOID,
    #[doc="TSTZRANGE"]
    PgTstzRange => TSTZRANGEOID
)

/// The wire format of a Postgres value
pub enum Format {
    /// A user-readable string format
    Text = 0,
    /// A machine-readable binary format
    Binary = 1
}

macro_rules! check_types(
    ($($expected:pat)|+, $actual:ident) => (
        match $actual {
            $(&$expected)|+ => (),
            actual => fail!("Invalid Postgres type {:?}", actual)
        }
    )
)

/// A trait for types that can be created from a Postgres value
pub trait FromSql {
    /// Creates a new value of this type from a buffer of Postgres data.
    ///
    /// If the value was `NULL`, the buffer will be `None`.
    ///
    /// # Failure
    ///
    /// Fails if this type can not be created from the provided Postgres type.
    fn from_sql(ty: &PostgresType, raw: &Option<~[u8]>) -> Self;
}

trait RawFromSql {
    fn raw_from_sql<R: Reader>(len: uint, raw: &mut R) -> Self;
}

macro_rules! raw_from_impl(
    ($t:ty, $f:ident) => (
        impl RawFromSql for $t {
            fn raw_from_sql<R: Reader>(_len: uint, raw: &mut R) -> $t {
                raw.$f()
            }
        }
    )
)

impl RawFromSql for bool {
    fn raw_from_sql<R: Reader>(_len: uint, raw: &mut R) -> bool {
        raw.read_u8() != 0
    }
}

impl RawFromSql for ~[u8] {
    fn raw_from_sql<R: Reader>(len: uint, raw: &mut R) -> ~[u8] {
        raw.read_bytes(len)
    }
}

impl RawFromSql for ~str {
    fn raw_from_sql<R: Reader>(len: uint, raw: &mut R) -> ~str {
        str::from_utf8_owned(raw.read_bytes(len))
    }
}

raw_from_impl!(i8, read_i8)
raw_from_impl!(i16, read_be_i16)
raw_from_impl!(i32, read_be_i32)
raw_from_impl!(i64, read_be_i64)
raw_from_impl!(f32, read_be_f32)
raw_from_impl!(f64, read_be_f64)

impl RawFromSql for Timespec {
    fn raw_from_sql<R: Reader>(_len: uint, raw: &mut R) -> Timespec {
        let t = raw.read_be_i64();
        let mut sec = t / USEC_PER_SEC + TIME_SEC_CONVERSION;
        let mut usec = t % USEC_PER_SEC;

        if usec < 0 {
            sec -= 1;
            usec = USEC_PER_SEC + usec;
        }

        Timespec::new(sec, (usec * NSEC_PER_USEC) as i32)
    }
}

macro_rules! from_map_impl(
    ($($expected:pat)|+, $t:ty, $blk:expr) => (
        impl FromSql for Option<$t> {
            fn from_sql(ty: &PostgresType, raw: &Option<~[u8]>) -> Option<$t> {
                check_types!($($expected)|+, ty)
                raw.as_ref().map($blk)
            }
        }

        impl FromSql for $t {
            fn from_sql(ty: &PostgresType, raw: &Option<~[u8]>) -> $t {
                // FIXME when you can specify Self types properly
                let ret: Option<$t> = FromSql::from_sql(ty, raw);
                ret.unwrap()
            }
        }
    )
)

macro_rules! from_raw_from_impl(
    ($($expected:pat)|+, $t:ty) => (
        from_map_impl!($($expected)|+, $t, |buf| {
            let mut reader = BufReader::new(buf.as_slice());
            RawFromSql::raw_from_sql(buf.len(), &mut reader)
        })
    )
)

from_raw_from_impl!(PgBool, bool)
from_raw_from_impl!(PgByteA, ~[u8])
from_raw_from_impl!(PgVarchar | PgText | PgCharN, ~str)
from_raw_from_impl!(PgChar, i8)
from_raw_from_impl!(PgInt2, i16)
from_raw_from_impl!(PgInt4, i32)
from_raw_from_impl!(PgInt8, i64)
from_raw_from_impl!(PgFloat4, f32)
from_raw_from_impl!(PgFloat8, f64)

from_map_impl!(PgJson, Json, |buf| {
    json::from_str(str::from_utf8(buf.as_slice())).unwrap()
})

from_map_impl!(PgUuid, Uuid, |buf| {
    Uuid::from_bytes(buf.as_slice()).unwrap()
})

from_raw_from_impl!(PgTimestamp | PgTimestampZ, Timespec)

macro_rules! from_range_impl(
    ($($oid:ident)|+, $t:ty) => (
        from_map_impl!($($oid)|+, Range<$t>, |buf| {
            let mut rdr = BufReader::new(buf.as_slice());
            let t = rdr.read_i8();

            if t & RANGE_EMPTY != 0 {
                Range::empty()
            } else {
                let lower = match t & RANGE_LOWER_UNBOUNDED {
                    0 => {
                        let type_ = match t & RANGE_LOWER_INCLUSIVE {
                            0 => Exclusive,
                            _ => Inclusive
                        };
                        let len = rdr.read_be_i32() as uint;
                        Some(RangeBound::new(
                                RawFromSql::raw_from_sql(len, &mut rdr), type_))
                    }
                    _ => None
                };
                let upper = match t & RANGE_UPPER_UNBOUNDED {
                    0 => {
                        let type_ = match t & RANGE_UPPER_INCLUSIVE {
                            0 => Exclusive,
                            _ => Inclusive
                        };
                        let len = rdr.read_be_i32() as uint;
                        Some(RangeBound::new(
                                RawFromSql::raw_from_sql(len, &mut rdr), type_))
                    }
                    _ => None
                };

                Range::new(lower, upper)
            }
        })
    )
)

from_range_impl!(PgInt4Range, i32)
from_range_impl!(PgInt8Range, i64)
from_range_impl!(PgTsRange | PgTstzRange, Timespec)

macro_rules! from_array_impl(
    ($($oid:ident)|+, $t:ty) => (
        from_map_impl!($($oid)|+, ArrayBase<Option<$t>>, |buf| {
            let mut rdr = BufReader::new(buf.as_slice());

            let ndim = rdr.read_be_i32() as uint;
            let _has_null = rdr.read_be_i32() == 1;
            let _element_type: Oid = rdr.read_be_i32();

            let mut dim_info = vec::with_capacity(ndim);
            for _ in range(0, ndim) {
                dim_info.push(DimensionInfo {
                    len: rdr.read_be_i32() as uint,
                    lower_bound: rdr.read_be_i32() as int
                });
            }
            let nele = dim_info.iter().fold(1, |acc, info| acc * info.len);

            let mut elements = vec::with_capacity(nele);
            for _ in range(0, nele) {
                let len = rdr.read_be_i32();
                if len < 0 {
                    elements.push(None);
                } else {
                    elements.push(Some(RawFromSql::raw_from_sql(len as uint,
                                                                &mut rdr)));
                }
            }

            ArrayBase::from_raw(elements, dim_info)
        })
    )
)

from_array_impl!(PgBoolArray, bool)
from_array_impl!(PgByteAArray, ~[u8])
from_array_impl!(PgCharArray, i8)
from_array_impl!(PgInt2Array, i16)
from_array_impl!(PgInt4Array, i32)
from_array_impl!(PgTextArray | PgCharNArray, ~str)
from_array_impl!(PgInt8Array, i64)
from_array_impl!(PgFloat4Array, f32)
from_array_impl!(PgFloat8Array, f64)

from_map_impl!(PgUnknownType { name: ~"hstore", .. },
               HashMap<~str, Option<~str>>, |buf| {
    let mut rdr = BufReader::new(buf.as_slice());
    let mut map = HashMap::new();

    let count = rdr.read_be_i32();

    for _ in range(0, count) {
        let key_len = rdr.read_be_i32();
        let key = str::from_utf8_owned(rdr.read_bytes(key_len as uint));

        let val_len = rdr.read_be_i32();
        let val = if val_len < 0 {
            None
        } else {
            Some(str::from_utf8_owned(rdr.read_bytes(val_len as uint)))
        };

        map.insert(key, val);
    }

    map
})

/// A trait for types that can be converted into Postgres values
pub trait ToSql {
    /// Converts the value of `self` into a format appropriate for the Postgres
    /// backend.
    ///
    /// # Failure
    ///
    /// Fails if this type cannot be converted into the specified Postgres
    /// type.
    fn to_sql(&self, ty: &PostgresType) -> (Format, Option<~[u8]>);
}

trait RawToSql {
    fn raw_to_sql<W: Writer>(&self, w: &mut W);

    fn raw_size(&self) -> uint;
}

macro_rules! raw_to_impl(
    ($t:ty, $f:ident) => (
        impl RawToSql for $t {
            fn raw_to_sql<W: Writer>(&self, w: &mut W) {
                w.$f(*self)
            }

            fn raw_size(&self) -> uint {
                mem::size_of::<$t>()
            }
        }
    )
)

impl RawToSql for bool {
    fn raw_to_sql<W: Writer>(&self, w: &mut W) {
        w.write_u8(*self as u8)
    }

    fn raw_size(&self) -> uint {
        1
    }
}

impl RawToSql for ~[u8] {
    fn raw_to_sql<W: Writer>(&self, w: &mut W) {
        w.write(self.as_slice())
    }

    fn raw_size(&self) -> uint {
        self.len()
    }
}

impl RawToSql for ~str {
    fn raw_to_sql<W: Writer>(&self, w: &mut W) {
        w.write(self.as_bytes())
    }

    fn raw_size(&self) -> uint {
        self.len()
    }
}

raw_to_impl!(i8, write_i8)
raw_to_impl!(i16, write_be_i16)
raw_to_impl!(i32, write_be_i32)
raw_to_impl!(i64, write_be_i64)
raw_to_impl!(f32, write_be_f32)
raw_to_impl!(f64, write_be_f64)

impl RawToSql for Timespec {
    fn raw_to_sql<W: Writer>(&self, w: &mut W) {
        let t = (self.sec - TIME_SEC_CONVERSION) * USEC_PER_SEC
            + self.nsec as i64 / NSEC_PER_USEC;
        w.write_be_i64(t);
    }

    fn raw_size(&self) -> uint {
        mem::size_of::<i64>()
    }
}

macro_rules! to_option_impl(
    ($($oid:pat)|+, $t:ty) => (
        impl ToSql for Option<$t> {
            fn to_sql(&self, ty: &PostgresType) -> (Format, Option<~[u8]>) {
                check_types!($($oid)|+, ty)

                match *self {
                    None => (Text, None),
                    Some(ref val) => val.to_sql(ty)
                }
            }
        }
    )
)

macro_rules! to_option_impl_self(
    ($($oid:pat)|+, $t:ty) => (
        impl<'self> ToSql for Option<$t> {
            fn to_sql(&self, ty: &PostgresType) -> (Format, Option<~[u8]>) {
                check_types!($($oid)|+, ty)

                match *self {
                    None => (Text, None),
                    Some(ref val) => val.to_sql(ty)
                }
            }
        }
    )
)

macro_rules! to_raw_to_impl(
    ($($oid:ident)|+, $t:ty) => (
        impl ToSql for $t {
            fn to_sql(&self, ty: &PostgresType) -> (Format, Option<~[u8]>) {
                check_types!($($oid)|+, ty)

                let mut writer = MemWriter::new();
                self.raw_to_sql(&mut writer);
                (Binary, Some(writer.inner()))
            }
        }

        to_option_impl!($($oid)|+, $t)
    )
)

to_raw_to_impl!(PgBool, bool)
to_raw_to_impl!(PgByteA, ~[u8])
to_raw_to_impl!(PgVarchar | PgText | PgCharN, ~str)
to_raw_to_impl!(PgChar, i8)
to_raw_to_impl!(PgInt2, i16)
to_raw_to_impl!(PgInt4, i32)
to_raw_to_impl!(PgInt8, i64)
to_raw_to_impl!(PgFloat4, f32)
to_raw_to_impl!(PgFloat8, f64)

impl<'self> ToSql for &'self str {
    fn to_sql(&self, ty: &PostgresType) -> (Format, Option<~[u8]>) {
        check_types!(PgVarchar | PgText | PgCharN, ty)
        (Text, Some(self.as_bytes().to_owned()))
    }
}

to_option_impl_self!(PgVarchar | PgText | PgCharN, &'self str)

impl<'self> ToSql for &'self [u8] {
    fn to_sql(&self, ty: &PostgresType) -> (Format, Option<~[u8]>) {
        check_types!(PgByteA, ty)
        (Binary, Some(self.to_owned()))
    }
}

to_option_impl_self!(PgByteA, &'self [u8])

impl ToSql for Json {
    fn to_sql(&self, ty: &PostgresType) -> (Format, Option<~[u8]>) {
        check_types!(PgJson, ty)
        (Text, Some(self.to_str().into_bytes()))
    }
}

to_option_impl!(PgJson, Json)

impl ToSql for Uuid {
    fn to_sql(&self, ty: &PostgresType) -> (Format, Option<~[u8]>) {
        check_types!(PgUuid, ty)
        (Binary, Some(self.to_bytes().to_owned()))
    }
}

to_option_impl!(PgUuid, Uuid)

to_raw_to_impl!(PgTimestamp | PgTimestampZ, Timespec)

macro_rules! to_range_impl(
    ($($oid:ident)|+, $t:ty) => (
        impl ToSql for Range<$t> {
            fn to_sql(&self, ty: &PostgresType) -> (Format, Option<~[u8]>) {
                check_types!($($oid)|+, ty)
                let mut buf = MemWriter::new();

                let mut tag = 0;
                if self.is_empty() {
                    tag |= RANGE_EMPTY;
                } else {
                    match *self.lower() {
                        None => tag |= RANGE_LOWER_UNBOUNDED,
                        Some(RangeBound { type_: Inclusive, .. }) =>
                            tag |= RANGE_LOWER_INCLUSIVE,
                        _ => {}
                    }
                    match *self.upper() {
                        None => tag |= RANGE_UPPER_UNBOUNDED,
                        Some(RangeBound { type_: Inclusive, .. }) =>
                            tag |= RANGE_UPPER_INCLUSIVE,
                        _ => {}
                    }
                }

                buf.write_i8(tag);

                match *self.lower() {
                    Some(ref bound) => {
                        buf.write_be_i32(bound.value.raw_size() as i32);
                        bound.value.raw_to_sql(&mut buf);
                    }
                    None => {}
                }
                match *self.upper() {
                    Some(ref bound) => {
                        buf.write_be_i32(bound.value.raw_size() as i32);
                        bound.value.raw_to_sql(&mut buf);
                    }
                    None => {}
                }

                (Binary, Some(buf.inner()))
            }
        }

        to_option_impl!($($oid)|+, Range<$t>)
    )
)

to_range_impl!(PgInt4Range, i32)
to_range_impl!(PgInt8Range, i64)
to_range_impl!(PgTsRange | PgTstzRange, Timespec)

macro_rules! to_array_impl(
    ($($oid:ident)|+, $t:ty) => (
        impl ToSql for ArrayBase<Option<$t>> {
            fn to_sql(&self, ty: &PostgresType) -> (Format, Option<~[u8]>) {
                check_types!($($oid)|+, ty)
                let mut buf = MemWriter::new();

                buf.write_be_i32(self.dimension_info().len() as i32);
                buf.write_be_i32(1);
                buf.write_be_i32(ty.member_type().to_oid());

                for info in self.dimension_info().iter() {
                    buf.write_be_i32(info.len as i32);
                    buf.write_be_i32(info.lower_bound as i32);
                }

                for v in self.values() {
                    match *v {
                        Some(ref val) => {
                            buf.write_be_i32(val.raw_size() as i32);
                            val.raw_to_sql(&mut buf);
                        }
                        None => buf.write_be_i32(-1)
                    }
                }

                (Binary, Some(buf.inner()))
            }
        }

        to_option_impl!($($oid)|+, ArrayBase<Option<$t>>)
    )
)

to_array_impl!(PgBoolArray, bool)
to_array_impl!(PgByteAArray, ~[u8])
to_array_impl!(PgCharArray, i8)
to_array_impl!(PgInt2Array, i16)
to_array_impl!(PgInt4Array, i32)
to_array_impl!(PgTextArray | PgCharNArray, ~str)
to_array_impl!(PgInt8Array, i64)
to_array_impl!(PgFloat4Array, f32)
to_array_impl!(PgFloat8Array, f64)

impl<'self> ToSql for HashMap<~str, Option<~str>> {
    fn to_sql(&self, ty: &PostgresType) -> (Format, Option<~[u8]>) {
        check_types!(PgUnknownType { name: ~"hstore", .. }, ty)
        let mut buf = MemWriter::new();

        buf.write_be_i32(self.len() as i32);

        for (key, val) in self.iter() {
            buf.write_be_i32(key.len() as i32);
            buf.write(key.as_bytes());

            match *val {
                Some(ref val) => {
                    buf.write_be_i32(val.len() as i32);
                    buf.write(val.as_bytes());
                }
                None => buf.write_be_i32(-1)
            }
        }

        (Binary, Some(buf.inner()))
    }
}
to_option_impl!(PgUnknownType { name: ~"hstore", .. },
                HashMap<~str, Option<~str>>)