package env

import (
	"os"
	"testing"
	"time"
)

func TestDuration(t *testing.T) {
	tests := []struct {
		name         string
		key          string
		value        string
		defaultValue time.Duration
		expected     time.Duration
		shouldSet    bool
	}{
		{"valid positive duration", "TEST_DURATION", "100", 0, 100 * time.Nanosecond, true},
		{"valid zero", "TEST_DURATION", "0", 10 * time.Second, 0, true},
		{"large value", "TEST_DURATION", "1000000000", 0, 1 * time.Second, true},
		{"valid negative duration", "TEST_DURATION", "-100", 0, -100 * time.Nanosecond, true},
		{"not set", "TEST_DURATION_NOTSET", "", 5 * time.Minute, 5 * time.Minute, false},
		{"invalid value", "TEST_DURATION", "not_a_number", 30 * time.Second, 30 * time.Second, true},
		{"empty string", "TEST_DURATION", "", 1 * time.Hour, 1 * time.Hour, true},
		{"float value", "TEST_DURATION", "10.5", 2 * time.Second, 2 * time.Second, true},
		{"very large value", "TEST_DURATION", "9223372036854775807", 0, 9223372036854775807 * time.Nanosecond, true},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			if tt.shouldSet {
				os.Setenv(tt.key, tt.value)
				defer os.Unsetenv(tt.key)
			}

			result := Duration(tt.key, tt.defaultValue)
			if result != tt.expected {
				t.Errorf("Duration() = %v, want %v", result, tt.expected)
			}
		})
	}
}