package compiler

import (
	"fmt"
	"testing"
)

func TestNewSymbolPosition(t *testing.T) {
	tests := []struct {
		n       uint16
		endMark bool
		err     bool
	}{
		{
			n:       0,
			endMark: false,
			err:     true,
		},
		{
			n:       0,
			endMark: true,
			err:     true,
		},
		{
			n:       symbolPositionMin - 1,
			endMark: false,
			err:     true,
		},
		{
			n:       symbolPositionMin - 1,
			endMark: true,
			err:     true,
		},
		{
			n:       symbolPositionMin,
			endMark: false,
		},
		{
			n:       symbolPositionMin,
			endMark: true,
		},
		{
			n:       symbolPositionMax,
			endMark: false,
		},
		{
			n:       symbolPositionMax,
			endMark: true,
		},
		{
			n:       symbolPositionMax + 1,
			endMark: false,
			err:     true,
		},
		{
			n:       symbolPositionMax + 1,
			endMark: true,
			err:     true,
		},
	}
	for i, tt := range tests {
		t.Run(fmt.Sprintf("#%v n: %v, endMark: %v", i, tt.n, tt.endMark), func(t *testing.T) {
			pos, err := newSymbolPosition(tt.n, tt.endMark)
			if tt.err {
				if err == nil {
					t.Fatal("err is nil")
				}
				return
			}
			if err != nil {
				t.Fatal(err)
			}
			n, endMark := pos.describe()
			if n != tt.n || endMark != tt.endMark {
				t.Errorf("unexpected symbol position; want: n: %v, endMark: %v, got: n: %v, endMark: %v", tt.n, tt.endMark, n, endMark)
			}
		})
	}
}

func TestASTNode(t *testing.T) {
	tests := []struct {
		root     astNode
		nullable bool
		first    *symbolPositionSet
		last     *symbolPositionSet
	}{
		{
			root:     newSymbolNodeWithPos(0, 1),
			nullable: false,
			first:    newSymbolPositionSet().add(1),
			last:     newSymbolPositionSet().add(1),
		},
		{
			root:     newEndMarkerNodeWithPos(1, 1),
			nullable: false,
			first:    newSymbolPositionSet().add(1),
			last:     newSymbolPositionSet().add(1),
		},
		{
			root: newConcatNode(
				newSymbolNodeWithPos(0, 1),
				newSymbolNodeWithPos(0, 2),
			),
			nullable: false,
			first:    newSymbolPositionSet().add(1),
			last:     newSymbolPositionSet().add(2),
		},
		{
			root: newConcatNode(
				newRepeatNode(newSymbolNodeWithPos(0, 1)),
				newSymbolNodeWithPos(0, 2),
			),
			nullable: false,
			first:    newSymbolPositionSet().add(1).add(2),
			last:     newSymbolPositionSet().add(2),
		},
		{
			root: newConcatNode(
				newSymbolNodeWithPos(0, 1),
				newRepeatNode(newSymbolNodeWithPos(0, 2)),
			),
			nullable: false,
			first:    newSymbolPositionSet().add(1),
			last:     newSymbolPositionSet().add(1).add(2),
		},
		{
			root: newConcatNode(
				newRepeatNode(newSymbolNodeWithPos(0, 1)),
				newRepeatNode(newSymbolNodeWithPos(0, 2)),
			),
			nullable: true,
			first:    newSymbolPositionSet().add(1).add(2),
			last:     newSymbolPositionSet().add(1).add(2),
		},
		{
			root: newAltNode(
				newSymbolNodeWithPos(0, 1),
				newSymbolNodeWithPos(0, 2),
			),
			nullable: false,
			first:    newSymbolPositionSet().add(1).add(2),
			last:     newSymbolPositionSet().add(1).add(2),
		},
		{
			root: newAltNode(
				newRepeatNode(newSymbolNodeWithPos(0, 1)),
				newSymbolNodeWithPos(0, 2),
			),
			nullable: true,
			first:    newSymbolPositionSet().add(1).add(2),
			last:     newSymbolPositionSet().add(1).add(2),
		},
		{
			root: newAltNode(
				newSymbolNodeWithPos(0, 1),
				newRepeatNode(newSymbolNodeWithPos(0, 2)),
			),
			nullable: true,
			first:    newSymbolPositionSet().add(1).add(2),
			last:     newSymbolPositionSet().add(1).add(2),
		},
		{
			root: newAltNode(
				newRepeatNode(newSymbolNodeWithPos(0, 1)),
				newRepeatNode(newSymbolNodeWithPos(0, 2)),
			),
			nullable: true,
			first:    newSymbolPositionSet().add(1).add(2),
			last:     newSymbolPositionSet().add(1).add(2),
		},
		{
			root:     newRepeatNode(newSymbolNodeWithPos(0, 1)),
			nullable: true,
			first:    newSymbolPositionSet().add(1),
			last:     newSymbolPositionSet().add(1),
		},
		{
			root:     newOptionNode(newSymbolNodeWithPos(0, 1)),
			nullable: true,
			first:    newSymbolPositionSet().add(1),
			last:     newSymbolPositionSet().add(1),
		},
	}
	for i, tt := range tests {
		t.Run(fmt.Sprintf("#%v", i), func(t *testing.T) {
			if tt.root.nullable() != tt.nullable {
				t.Errorf("unexpected nullable attribute; want: %v, got: %v", tt.nullable, tt.root.nullable())
			}
			if tt.first.hash() != tt.root.first().hash() {
				t.Errorf("unexpected first positions attribute; want: %v, got: %v", tt.first, tt.root.first())
			}
			if tt.last.hash() != tt.root.last().hash() {
				t.Errorf("unexpected last positions attribute; want: %v, got: %v", tt.last, tt.root.last())
			}
		})
	}
}