// Copyright 2024 Dolthub, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package functions

import (
	"cmp"
	"fmt"
	"math"
	"strconv"
	"strings"

	"github.com/dolthub/go-mysql-server/sql"

	"github.com/dolthub/doltgresql/core/id"
	"github.com/dolthub/doltgresql/server/functions/framework"
	pgtypes "github.com/dolthub/doltgresql/server/types"
	"github.com/dolthub/doltgresql/utils"
)

// initOid registers the functions to the catalog.
func initOid() {
	framework.RegisterFunction(oidin)
	framework.RegisterFunction(oidout)
	framework.RegisterFunction(oidrecv)
	framework.RegisterFunction(oidsend)
	framework.RegisterFunction(btoidcmp)
}

// oidin represents the PostgreSQL function of oid type IO input.
var oidin = framework.Function1{
	Name:       "oidin",
	Return:     pgtypes.Oid,
	Parameters: [1]*pgtypes.DoltgresType{pgtypes.Cstring},
	Strict:     true,
	Callable: func(ctx *sql.Context, _ [2]*pgtypes.DoltgresType, val any) (any, error) {
		input := val.(string)
		iVal, err := strconv.ParseInt(strings.TrimSpace(input), 10, 64)
		if err != nil {
			return id.Null, pgtypes.ErrInvalidSyntaxForType.New("oid", input)
		}
		// Note: This minimum is different (-4294967295) for Postgres 15.4 compiled by Visual C++
		if iVal > int64(math.MaxUint32) || iVal < int64(math.MinInt32) {
			return id.Null, pgtypes.ErrValueIsOutOfRangeForType.New(input, "oid")
		}
		uVal := uint32(iVal)
		if internalID := id.Cache().ToInternal(uVal); internalID.IsValid() {
			return internalID, nil
		}
		return id.NewOID(uVal).AsId(), nil
	},
}

// oidout represents the PostgreSQL function of oid type IO output.
var oidout = framework.Function1{
	Name:       "oidout",
	Return:     pgtypes.Cstring,
	Parameters: [1]*pgtypes.DoltgresType{pgtypes.Oid},
	Strict:     true,
	Callable: func(ctx *sql.Context, _ [2]*pgtypes.DoltgresType, val any) (any, error) {
		return fmt.Sprintf("%d", id.Cache().ToOID(val.(id.Id))), nil
	},
}

// oidrecv represents the PostgreSQL function of oid type IO receive.
var oidrecv = framework.Function1{
	Name:       "oidrecv",
	Return:     pgtypes.Oid,
	Parameters: [1]*pgtypes.DoltgresType{pgtypes.Internal},
	Strict:     true,
	Callable: func(ctx *sql.Context, _ [2]*pgtypes.DoltgresType, val any) (any, error) {
		data := val.([]byte)
		if data == nil {
			return nil, nil
		}
		reader := utils.NewWireReader(data)
		readValue := reader.ReadUint32()
		cachedID := id.Cache().ToInternal(readValue)
		if cachedID.IsValid() {
			return cachedID, nil
		}
		return id.NewOID(readValue).AsId(), nil
	},
}

// oidsend represents the PostgreSQL function of oid type IO send.
var oidsend = framework.Function1{
	Name:       "oidsend",
	Return:     pgtypes.Bytea,
	Parameters: [1]*pgtypes.DoltgresType{pgtypes.Oid},
	Strict:     true,
	Callable: func(ctx *sql.Context, _ [2]*pgtypes.DoltgresType, val any) (any, error) {
		writer := utils.NewWireWriter()
		writer.WriteUint32(id.Cache().ToOID(val.(id.Id)))
		return writer.BufferData(), nil
	},
}

// btoidcmp represents the PostgreSQL function of oid type compare.
var btoidcmp = framework.Function2{
	Name:       "btoidcmp",
	Return:     pgtypes.Int32,
	Parameters: [2]*pgtypes.DoltgresType{pgtypes.Oid, pgtypes.Oid},
	Strict:     true,
	Callable: func(ctx *sql.Context, _ [3]*pgtypes.DoltgresType, val1, val2 any) (any, error) {
		return int32(cmp.Compare(val1.(id.Id), val2.(id.Id))), nil
	},
}