package cmdlang

import (
	"bytes"
	"context"
	"fmt"
	"github.com/stretchr/testify/assert"
	"strings"
	"testing"
)

// Builtins used for test
func WithTestBuiltin() InstOption {
	return func(i *Inst) {
		i.rootEC.addCmd("firstarg", invokableFunc(func(ctx context.Context, args invocationArgs) (object, error) {
			return args.args[0], nil
		}))

		i.rootEC.addCmd("sjoin", invokableFunc(func(ctx context.Context, args invocationArgs) (object, error) {
			if len(args.args) == 0 {
				return strObject(""), nil
			}

			var line strings.Builder
			for _, arg := range args.args {
				if s, ok := arg.(fmt.Stringer); ok {
					line.WriteString(s.String())
				}
			}

			return strObject(line.String()), nil
		}))

		i.rootEC.addCmd("pipe", invokableFunc(func(ctx context.Context, args invocationArgs) (object, error) {
			return &listIterStream{
				list: args.args,
			}, nil
		}))

		i.rootEC.addCmd("joinpipe", invokableStreamFunc(func(ctx context.Context, inStream stream, args invocationArgs) (object, error) {
			sb := strings.Builder{}
			if err := forEach(inStream, func(o object, i int) error {
				if i > 0 {
					sb.WriteString(",")
				}
				sb.WriteString(o.String())
				return nil
			}); err != nil {
				return nil, err
			}
			return strObject(sb.String()), nil
		}))

		i.rootEC.setVar("a", strObject("alpha"))
		i.rootEC.setVar("bee", strObject("buzz"))
	}
}

func TestBuiltins_Echo(t *testing.T) {
	tests := []struct {
		desc string
		expr string
		want string
	}{
		{desc: "no args", expr: `echo`, want: "\n"},
		{desc: "single arg", expr: `echo "hello"`, want: "hello\n"},
		{desc: "dual args", expr: `echo "hello " "world"`, want: "hello world\n"},
		{desc: "multi-line 1", expr: `
			echo "Hello"
			echo "world"
		`, want: "Hello\nworld\n"},
		{desc: "multi-line 2", expr: `
			echo "Hello"


			echo "world"
		`, want: "Hello\nworld\n"},
		{desc: "multi-line 3", expr: `

;;;
			echo "Hello"
;

			echo "world"
;
		`, want: "Hello\nworld\n"},
	}

	for _, tt := range tests {
		t.Run(tt.desc, func(t *testing.T) {
			ctx := context.Background()
			outW := bytes.NewBuffer(nil)

			inst := New(WithOut(outW), WithTestBuiltin())
			res, err := inst.Eval(ctx, tt.expr)

			assert.NoError(t, err)
			assert.Nil(t, res)
			assert.Equal(t, tt.want, outW.String())
		})
	}
}

func TestBuiltins_If(t *testing.T) {
	tests := []struct {
		desc string
		expr string
		want string
	}{
		{desc: "single then", expr: `
			set x "Hello"
			if $x {
				echo "true"
			}`, want: "true\n(nil)\n"},
		{desc: "single then and else", expr: `
			set x "Hello"
			if $x {
				echo "true"
			} else {
				echo "false"
			}`, want: "true\n(nil)\n"},
		{desc: "single then, elif and else", expr: `
			set x "Hello"
			if $y {
				echo "y is true"
			} elif $x {
				echo "x is true"
			} else {
				echo "nothings x"
			}`, want: "x is true\n(nil)\n"},
		{desc: "single then and elif, no else", expr: `
			set x "Hello"
			if $y {
				echo "y is true"
			} elif $x {
				echo "x is true"
			}`, want: "x is true\n(nil)\n"},
		{desc: "single then, two elif, and else", expr: `
			set x "Hello"
			if $z {
				echo "z is true"
			} elif $y {
				echo "y is true"
			} elif $x {
				echo "x is true"
			}`, want: "x is true\n(nil)\n"},
		{desc: "single then, two elif, and else, expecting else", expr: `
			if $z {
				echo "z is true"
			} elif $y {
				echo "y is true"
			} elif $x {
				echo "x is true"
			} else {
				echo "none is true"
			}`, want: "none is true\n(nil)\n"},
		{desc: "compressed then", expr: `set x "Hello" ; if $x { echo "true" }`, want: "true\n(nil)\n"},
		{desc: "compressed else", expr: `if $x { echo "true" } else { echo "false" }`, want: "false\n(nil)\n"},
		{desc: "compressed if", expr: `if $x { echo "x" } elif $y { echo "y" } else { echo "false" }`, want: "false\n(nil)\n"},
	}

	for _, tt := range tests {
		t.Run(tt.desc, func(t *testing.T) {
			ctx := context.Background()
			outW := bytes.NewBuffer(nil)

			inst := New(WithOut(outW), WithTestBuiltin())
			err := inst.EvalAndDisplay(ctx, tt.expr)

			assert.NoError(t, err)
			assert.Equal(t, tt.want, outW.String())
		})
	}
}

func TestBuiltins_ForEach(t *testing.T) {
	tests := []struct {
		desc string
		expr string
		want string
	}{
		{desc: "iterate over list", expr: `
			foreach ["1" "2" "3"] { |v|
				echo $v
			}`, want: "1\n2\n3\n(nil)\n"},
		{desc: "iterate over map", expr: `
			foreach [a:"1"] { |k v| echo $k "=" $v }`, want: "a=1\n(nil)\n"},
	}

	for _, tt := range tests {
		t.Run(tt.desc, func(t *testing.T) {
			ctx := context.Background()
			outW := bytes.NewBuffer(nil)

			inst := New(WithOut(outW), WithTestBuiltin())
			err := inst.EvalAndDisplay(ctx, tt.expr)

			assert.NoError(t, err)
			assert.Equal(t, tt.want, outW.String())
		})
	}
}