package cli

import (
	"testing"
	"time"

	"github.com/stretchr/testify/assert"
)

func TestParseDuration(t *testing.T) {
	tests := []struct {
		name     string
		input    string
		expected time.Duration
		wantErr  bool
	}{
		// Standard Go durations
		{
			name:     "standard seconds",
			input:    "30s",
			expected: 30 * time.Second,
		},
		{
			name:     "standard minutes",
			input:    "45m",
			expected: 45 * time.Minute,
		},
		{
			name:     "standard hours",
			input:    "2h",
			expected: 2 * time.Hour,
		},
		{
			name:     "standard combined",
			input:    "3h30m",
			expected: 3*time.Hour + 30*time.Minute,
		},
		{
			name:     "standard complex",
			input:    "1h45m30s",
			expected: 1*time.Hour + 45*time.Minute + 30*time.Second,
		},
		{
			name:     "standard with milliseconds",
			input:    "1s500ms",
			expected: 1*time.Second + 500*time.Millisecond,
		},
		// Extended units - days
		{
			name:     "single day",
			input:    "1d",
			expected: 24 * time.Hour,
		},
		{
			name:     "multiple days",
			input:    "7d",
			expected: 7 * 24 * time.Hour,
		},
		{
			name:     "fractional days",
			input:    "1.5d",
			expected: 36 * time.Hour,
		},
		{
			name:     "days spelled out",
			input:    "3days",
			expected: 3 * 24 * time.Hour,
		},
		// Extended units - weeks
		{
			name:     "single week",
			input:    "1w",
			expected: 7 * 24 * time.Hour,
		},
		{
			name:     "multiple weeks",
			input:    "4w",
			expected: 4 * 7 * 24 * time.Hour,
		},
		{
			name:     "weeks spelled out",
			input:    "2weeks",
			expected: 2 * 7 * 24 * time.Hour,
		},
		// Extended units - months
		{
			name:     "single month",
			input:    "1mo",
			expected: 30 * 24 * time.Hour,
		},
		{
			name:     "multiple months",
			input:    "6mo",
			expected: 6 * 30 * 24 * time.Hour,
		},
		{
			name:     "months spelled out",
			input:    "3months",
			expected: 3 * 30 * 24 * time.Hour,
		},
		// Extended units - years
		{
			name:     "single year",
			input:    "1y",
			expected: 365 * 24 * time.Hour,
		},
		{
			name:     "multiple years",
			input:    "2y",
			expected: 2 * 365 * 24 * time.Hour,
		},
		{
			name:     "years spelled out",
			input:    "1year",
			expected: 365 * 24 * time.Hour,
		},
		// Combined extended units
		{
			name:     "weeks and days",
			input:    "2w3d",
			expected: 2*7*24*time.Hour + 3*24*time.Hour,
		},
		{
			name:     "years and months",
			input:    "1y6mo",
			expected: 365*24*time.Hour + 6*30*24*time.Hour,
		},
		{
			name:     "days and hours",
			input:    "1d12h",
			expected: 24*time.Hour + 12*time.Hour,
		},
		{
			name:     "complex combination",
			input:    "1y2mo3w4d5h6m7s",
			expected: 365*24*time.Hour + 2*30*24*time.Hour + 3*7*24*time.Hour + 4*24*time.Hour + 5*time.Hour + 6*time.Minute + 7*time.Second,
		},
		{
			name:     "with spaces",
			input:    "1d 12h 30m",
			expected: 24*time.Hour + 12*time.Hour + 30*time.Minute,
		},
		// Edge cases
		{
			name:     "zero duration",
			input:    "0s",
			expected: 0,
		},
		{
			name:     "large duration",
			input:    "10y",
			expected: 10 * 365 * 24 * time.Hour,
		},
		// Error cases
		{
			name:    "empty string",
			input:   "",
			wantErr: true,
		},
		{
			name:    "invalid format",
			input:   "abc",
			wantErr: true,
		},
		{
			name:    "unknown unit",
			input:   "5x",
			wantErr: true,
		},
		{
			name:    "invalid number",
			input:   "xyzd",
			wantErr: true,
		},
		{
			name:    "negative not supported",
			input:   "-5d",
			wantErr: true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got, err := parseDuration(tt.input)

			if tt.wantErr {
				assert.Error(t, err, "expected error for input %q", tt.input)
				return
			}

			assert.NoError(t, err, "unexpected error for input %q", tt.input)
			assert.Equal(t, tt.expected, got, "duration mismatch for input %q", tt.input)
		})
	}
}

func TestParseDurationSpecialCases(t *testing.T) {
	// Test that standard Go durations work exactly as expected
	standardDurations := []string{
		"300ms",
		"1.5h",
		"2h45m",
		"72h",
		"1us",
		"1µs",
		"1ns",
	}

	for _, d := range standardDurations {
		expected, err := time.ParseDuration(d)
		assert.NoError(t, err)

		got, err := parseDuration(d)
		assert.NoError(t, err)
		assert.Equal(t, expected, got, "standard duration %q should parse identically", d)
	}
}

func TestParseDurationRealWorldExamples(t *testing.T) {
	// Test real-world snapshot purge scenarios
	tests := []struct {
		description string
		input       string
		olderThan   time.Duration
	}{
		{
			description: "keep snapshots from last 30 days",
			input:       "30d",
			olderThan:   30 * 24 * time.Hour,
		},
		{
			description: "keep snapshots from last 6 months",
			input:       "6mo",
			olderThan:   6 * 30 * 24 * time.Hour,
		},
		{
			description: "keep snapshots from last year",
			input:       "1y",
			olderThan:   365 * 24 * time.Hour,
		},
		{
			description: "keep snapshots from last week and a half",
			input:       "1w3d",
			olderThan:   10 * 24 * time.Hour,
		},
		{
			description: "keep snapshots from last 90 days",
			input:       "90d",
			olderThan:   90 * 24 * time.Hour,
		},
	}

	for _, tt := range tests {
		t.Run(tt.description, func(t *testing.T) {
			got, err := parseDuration(tt.input)
			assert.NoError(t, err)
			assert.Equal(t, tt.olderThan, got)

			// Verify the duration makes sense for snapshot purging
			assert.Greater(t, got, time.Hour, "snapshot purge duration should be at least an hour")
		})
	}
}