// Copyright 2017 The Wuffs Authors.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//
// SPDX-License-Identifier: Apache-2.0 OR MIT

package check

import (
	"fmt"

	"github.com/google/wuffs/lang/builtin"

	a "github.com/google/wuffs/lang/ast"
	t "github.com/google/wuffs/lang/token"
)

var (
	exprArgs    = a.NewExpr(0, 0, t.IDArgs, nil, nil, nil, nil)
	exprNullptr = a.NewExpr(0, 0, t.IDNullptr, nil, nil, nil, nil)
	exprThis    = a.NewExpr(0, 0, t.IDThis, nil, nil, nil, nil)
)

var (
	typeExprGeneric1    = a.NewTypeExpr(0, t.IDBase, t.IDDagger1, nil, nil, nil)
	typeExprGeneric2    = a.NewTypeExpr(0, t.IDBase, t.IDDagger2, nil, nil, nil)
	typeExprGenericRo1  = a.NewTypeExpr(0, t.IDBase, t.IDRho1, nil, nil, nil)
	typeExprIdeal       = a.NewTypeExpr(0, t.IDBase, t.IDQIdeal, nil, nil, nil)
	typeExprList        = a.NewTypeExpr(0, t.IDBase, t.IDComma, nil, nil, nil)
	typeExprNonNullptr  = a.NewTypeExpr(0, t.IDBase, t.IDQNonNullptr, nil, nil, nil)
	typeExprNullptr     = a.NewTypeExpr(0, t.IDBase, t.IDQNullptr, nil, nil, nil)
	typeExprPackage     = a.NewTypeExpr(0, t.IDBase, t.IDQPackage, nil, nil, nil)
	typeExprPlaceholder = a.NewTypeExpr(0, t.IDBase, t.IDQPlaceholder, nil, nil, nil)
	typeExprTypeExpr    = a.NewTypeExpr(0, t.IDBase, t.IDQTypeExpr, nil, nil, nil)

	typeExprU8  = a.NewTypeExpr(0, t.IDBase, t.IDU8, nil, nil, nil)
	typeExprU16 = a.NewTypeExpr(0, t.IDBase, t.IDU16, nil, nil, nil)
	typeExprU32 = a.NewTypeExpr(0, t.IDBase, t.IDU32, nil, nil, nil)
	typeExprU64 = a.NewTypeExpr(0, t.IDBase, t.IDU64, nil, nil, nil)

	typeExprBitvec256 = a.NewTypeExpr(0, t.IDBase, t.IDBitvec256, nil, nil, nil)

	typeExprOptionalU63 = a.NewTypeExpr(0, t.IDBase, t.IDOptionalU63, nil, nil, nil)

	typeExprEmptyStruct = a.NewTypeExpr(0, t.IDBase, t.IDEmptyStruct, nil, nil, nil)
	typeExprBool        = a.NewTypeExpr(0, t.IDBase, t.IDBool, nil, nil, nil)
	typeExprUtility     = a.NewTypeExpr(0, t.IDBase, t.IDUtility, nil, nil, nil)

	typeExprRangeIEU32 = a.NewTypeExpr(0, t.IDBase, t.IDRangeIEU32, nil, nil, nil)
	typeExprRangeIIU32 = a.NewTypeExpr(0, t.IDBase, t.IDRangeIIU32, nil, nil, nil)
	typeExprRangeIEU64 = a.NewTypeExpr(0, t.IDBase, t.IDRangeIEU64, nil, nil, nil)
	typeExprRangeIIU64 = a.NewTypeExpr(0, t.IDBase, t.IDRangeIIU64, nil, nil, nil)
	typeExprRectIEU32  = a.NewTypeExpr(0, t.IDBase, t.IDRectIEU32, nil, nil, nil)
	typeExprRectIIU32  = a.NewTypeExpr(0, t.IDBase, t.IDRectIIU32, nil, nil, nil)

	typeExprMoreInformation = a.NewTypeExpr(0, t.IDBase, t.IDMoreInformation, nil, nil, nil)

	typeExprStatus = a.NewTypeExpr(0, t.IDBase, t.IDStatus, nil, nil, nil)

	typeExprIOReader    = a.NewTypeExpr(0, t.IDBase, t.IDIOReader, nil, nil, nil)
	typeExprIOWriter    = a.NewTypeExpr(0, t.IDBase, t.IDIOWriter, nil, nil, nil)
	typeExprTokenReader = a.NewTypeExpr(0, t.IDBase, t.IDTokenReader, nil, nil, nil)
	typeExprTokenWriter = a.NewTypeExpr(0, t.IDBase, t.IDTokenWriter, nil, nil, nil)

	typeExprFrameConfig   = a.NewTypeExpr(0, t.IDBase, t.IDFrameConfig, nil, nil, nil)
	typeExprImageConfig   = a.NewTypeExpr(0, t.IDBase, t.IDImageConfig, nil, nil, nil)
	typeExprPixelBlend    = a.NewTypeExpr(0, t.IDBase, t.IDPixelBlend, nil, nil, nil)
	typeExprPixelBuffer   = a.NewTypeExpr(0, t.IDBase, t.IDPixelBuffer, nil, nil, nil)
	typeExprPixelConfig   = a.NewTypeExpr(0, t.IDBase, t.IDPixelConfig, nil, nil, nil)
	typeExprPixelFormat   = a.NewTypeExpr(0, t.IDBase, t.IDPixelFormat, nil, nil, nil)
	typeExprPixelSwizzler = a.NewTypeExpr(0, t.IDBase, t.IDPixelSwizzler, nil, nil, nil)

	typeExprDecodeFrameOptions = a.NewTypeExpr(0, t.IDBase, t.IDDecodeFrameOptions, nil, nil, nil)

	typeExprARMCRC32Utility = a.NewTypeExpr(0, t.IDBase, t.IDARMCRC32Utility, nil, nil, nil)
	typeExprARMCRC32U32     = a.NewTypeExpr(0, t.IDBase, t.IDARMCRC32U32, nil, nil, nil)

	typeExprARMNeonUtility = a.NewTypeExpr(0, t.IDBase, t.IDARMNeonUtility, nil, nil, nil)
	typeExprARMNeonU8x8    = a.NewTypeExpr(0, t.IDBase, t.IDARMNeonU8x8, nil, nil, nil)
	typeExprARMNeonU16x4   = a.NewTypeExpr(0, t.IDBase, t.IDARMNeonU16x4, nil, nil, nil)
	typeExprARMNeonU32x2   = a.NewTypeExpr(0, t.IDBase, t.IDARMNeonU32x2, nil, nil, nil)
	typeExprARMNeonU64x1   = a.NewTypeExpr(0, t.IDBase, t.IDARMNeonU64x1, nil, nil, nil)
	typeExprARMNeonU8x16   = a.NewTypeExpr(0, t.IDBase, t.IDARMNeonU8x16, nil, nil, nil)
	typeExprARMNeonU16x8   = a.NewTypeExpr(0, t.IDBase, t.IDARMNeonU16x8, nil, nil, nil)
	typeExprARMNeonU32x4   = a.NewTypeExpr(0, t.IDBase, t.IDARMNeonU32x4, nil, nil, nil)
	typeExprARMNeonU64x2   = a.NewTypeExpr(0, t.IDBase, t.IDARMNeonU64x2, nil, nil, nil)

	typeExprX86SSE42Utility = a.NewTypeExpr(0, t.IDBase, t.IDX86SSE42Utility, nil, nil, nil)
	typeExprX86M128I        = a.NewTypeExpr(0, t.IDBase, t.IDX86M128I, nil, nil, nil)

	typeExprX86AVX2Utility = a.NewTypeExpr(0, t.IDBase, t.IDX86AVX2Utility, nil, nil, nil)
	typeExprX86M256I       = a.NewTypeExpr(0, t.IDBase, t.IDX86M256I, nil, nil, nil)

	typeExprRosliceU8 = a.NewTypeExpr(t.IDRoslice, 0, 0, nil, nil, typeExprU8)
	typeExprRotableU8 = a.NewTypeExpr(t.IDRotable, 0, 0, nil, nil, typeExprU8)
	typeExprSliceU8   = a.NewTypeExpr(t.IDSlice, 0, 0, nil, nil, typeExprU8)
	typeExprTableU8   = a.NewTypeExpr(t.IDTable, 0, 0, nil, nil, typeExprU8)
)

func setPlaceholderMBoundsMType(n *a.Node) {
	n.SetMBounds(bounds{zero, zero})
	n.SetMType(typeExprPlaceholder)
}

// typeMap maps from variable names (as token IDs) to types.
type typeMap map[t.ID]*a.TypeExpr

var builtInTypeMap = typeMap{
	t.IDU8:  typeExprU8,
	t.IDU16: typeExprU16,
	t.IDU32: typeExprU32,
	t.IDU64: typeExprU64,

	t.IDBitvec256: typeExprBitvec256,

	t.IDOptionalU63: typeExprOptionalU63,

	t.IDEmptyStruct: typeExprEmptyStruct,
	t.IDBool:        typeExprBool,
	t.IDUtility:     typeExprUtility,

	t.IDRangeIEU32: typeExprRangeIEU32,
	t.IDRangeIIU32: typeExprRangeIIU32,
	t.IDRangeIEU64: typeExprRangeIEU64,
	t.IDRangeIIU64: typeExprRangeIIU64,
	t.IDRectIEU32:  typeExprRectIEU32,
	t.IDRectIIU32:  typeExprRectIIU32,

	t.IDMoreInformation: typeExprMoreInformation,

	t.IDStatus: typeExprStatus,

	t.IDIOReader:    typeExprIOReader,
	t.IDIOWriter:    typeExprIOWriter,
	t.IDTokenReader: typeExprTokenReader,
	t.IDTokenWriter: typeExprTokenWriter,

	t.IDFrameConfig:   typeExprFrameConfig,
	t.IDImageConfig:   typeExprImageConfig,
	t.IDPixelBlend:    typeExprPixelBlend,
	t.IDPixelBuffer:   typeExprPixelBuffer,
	t.IDPixelConfig:   typeExprPixelConfig,
	t.IDPixelFormat:   typeExprPixelFormat,
	t.IDPixelSwizzler: typeExprPixelSwizzler,

	t.IDDecodeFrameOptions: typeExprDecodeFrameOptions,

	t.IDARMCRC32Utility: typeExprARMCRC32Utility,
	t.IDARMCRC32U32:     typeExprARMCRC32U32,

	t.IDARMNeonUtility: typeExprARMNeonUtility,
	t.IDARMNeonU8x8:    typeExprARMNeonU8x8,
	t.IDARMNeonU16x4:   typeExprARMNeonU16x4,
	t.IDARMNeonU32x2:   typeExprARMNeonU32x2,
	t.IDARMNeonU64x1:   typeExprARMNeonU64x1,
	t.IDARMNeonU8x16:   typeExprARMNeonU8x16,
	t.IDARMNeonU16x8:   typeExprARMNeonU16x8,
	t.IDARMNeonU32x4:   typeExprARMNeonU32x4,
	t.IDARMNeonU64x2:   typeExprARMNeonU64x2,

	t.IDX86SSE42Utility: typeExprX86SSE42Utility,
	t.IDX86M128I:        typeExprX86M128I,

	t.IDX86AVX2Utility: typeExprX86AVX2Utility,
	t.IDX86M256I:       typeExprX86M256I,
}

func (c *Checker) parseBuiltInFuncs(m map[t.QQID]*a.Func, mRonly map[t.QQID]*a.Func, ss []string) error {
	return builtin.ParseFuncs(c.tm, ss, func(f *a.Func) error {
		if err := c.checkFuncSignature1(f.AsNode(), false); err != nil {
			return err
		}
		if m != nil {
			m[f.QQID()] = f
		}
		if (mRonly != nil) && f.Effect().Pure() {
			mRonly[f.QQID()] = f
		}
		return nil
	})
}

func (c *Checker) resolveFunc(typ *a.TypeExpr) (*a.Func, error) {
	if typ.Decorator() != t.IDFunc {
		return nil, fmt.Errorf("check: resolveFunc cannot look up non-func TypeExpr %q", typ.Str(c.tm))
	}
	lTyp := typ.Receiver()
	lQID := lTyp.QID()
	qqid := t.QQID{lQID[0], lQID[1], typ.FuncName()}

	if lTyp.IsEitherSliceType() {
		qqid[0] = t.IDBase
		qqid[1] = t.IDDagger1
		if f := c.builtInSliceFuncs[qqid]; f != nil {
			if (lTyp.Decorator() == t.IDSlice) || f.Effect().Pure() {
				return f, nil
			}
		}
		if lTyp.Eq(typeExprSliceU8) || lTyp.Eq(typeExprRosliceU8) {
			if f := c.builtInSliceU8Funcs[qqid]; f != nil {
				if (lTyp.Decorator() == t.IDSlice) || f.Effect().Pure() {
					return f, nil
				}
			}
		}

	} else if lTyp.IsEitherTableType() {
		qqid[0] = t.IDBase
		qqid[1] = t.IDDagger2
		if f := c.builtInTableFuncs[qqid]; f != nil {
			if (lTyp.Decorator() == t.IDTable) || f.Effect().Pure() {
				return f, nil
			}
		}

	} else if f := c.funcs[qqid]; f != nil {
		return f, nil
	}
	return nil, fmt.Errorf("check: resolveFunc cannot look up %q", typ.Str(c.tm))
}