package calculator

import (
	"strings"
	"testing"
)

func TestEvaluateBasicArithmetic(t *testing.T) {
	tests := []struct {
		expression string
		want       float64
	}{
		{expression: "1+2*3", want: 7},
		{expression: "(1+2)*3", want: 9},
		{expression: "12.5*(3+4)/2", want: 43.75},
		{expression: "-2 + 3", want: 1},
		{expression: "（8＋4）÷3", want: 4},
	}
	for _, tt := range tests {
		got, err := Evaluate(tt.expression)
		if err != nil {
			t.Fatalf("Evaluate(%q) error: %v", tt.expression, err)
		}
		if got != tt.want {
			t.Fatalf("Evaluate(%q) = %v, want %v", tt.expression, got, tt.want)
		}
	}
}

func TestEvaluateErrors(t *testing.T) {
	for _, expression := range []string{"1/0", "1+", "(1+2", "2^3"} {
		if _, err := Evaluate(expression); err == nil {
			t.Fatalf("Evaluate(%q) expected error", expression)
		}
	}
}

func TestToolDefinitionAndExecuteTool(t *testing.T) {
	definition := ToolDefinition("custom calculator")
	if definition.Function == nil || definition.Function.Name != ToolName || definition.Function.Description != "custom calculator" {
		t.Fatalf("unexpected definition: %#v", definition)
	}
	text, err := ExecuteTool(`{"expression":"12.5*(3+4)/2","reason":"用户询问计算结果"}`)
	if err != nil {
		t.Fatal(err)
	}
	for _, want := range []string{"计算器工具结果", "12.5*(3+4)/2", "43.75", "用户询问计算结果"} {
		if !strings.Contains(text, want) {
			t.Fatalf("tool result missing %q:\n%s", want, text)
		}
	}
}