package proxmox

import (
	"encoding/json"
	"fmt"
	"testing"
)

func TestDiskUnmarshalWearout(t *testing.T) {
	tests := []struct {
		name     string
		wearout  json.RawMessage
		expected int
	}{
		{
			name:     "numeric",
			wearout:  json.RawMessage(`81`),
			expected: 81,
		},
		{
			name:     "numeric string",
			wearout:  json.RawMessage(`"81"`),
			expected: 81,
		},
		{
			name:     "escaped numeric string",
			wearout:  json.RawMessage(`"\"81\""`),
			expected: 81,
		},
		{
			name:     "percentage string",
			wearout:  json.RawMessage(`"81%"`),
			expected: 81,
		},
		{
			name:     "percentage with spaces",
			wearout:  json.RawMessage(`"  82 % "`),
			expected: 82,
		},
		{
			name:     "not applicable string",
			wearout:  json.RawMessage(`"N/A"`),
			expected: wearoutUnknown,
		},
		{
			name:     "empty string",
			wearout:  json.RawMessage(`""`),
			expected: wearoutUnknown,
		},
		{
			name:     "null value",
			wearout:  json.RawMessage(`null`),
			expected: wearoutUnknown,
		},
		{
			name:     "unknown string",
			wearout:  json.RawMessage(`"Unknown"`),
			expected: wearoutUnknown,
		},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			payload := fmt.Sprintf(`{"devpath":"/dev/sda","model":"Example","serial":"123","type":"hdd","health":"OK","wearout":%s,"size":1000,"rpm":7200,"used":"LVM","vendor":"Example","wwn":"example"}`, tc.wearout)
			var disk Disk
			if err := json.Unmarshal([]byte(payload), &disk); err != nil {
				t.Fatalf("unexpected error unmarshalling disk: %v", err)
			}
			if disk.Wearout != tc.expected {
				t.Fatalf("wearout: got %d, want %d", disk.Wearout, tc.expected)
			}
		})
	}
}

func TestVMFileSystemUnmarshalFlexibleNumbers(t *testing.T) {
	t.Run("accepts numeric values", func(t *testing.T) {
		payload := `{"name":"rootfs","type":"zfs","mountpoint":"/","total-bytes":8589934592,"used-bytes":3221225472,"disk":[{"dev":"/dev/vtbd0p2"}]}`
		var fs VMFileSystem
		if err := json.Unmarshal([]byte(payload), &fs); err != nil {
			t.Fatalf("unexpected error unmarshalling numeric fields: %v", err)
		}
		if fs.TotalBytes != 8589934592 || fs.UsedBytes != 3221225472 {
			t.Fatalf("unexpected numeric values: got total=%d used=%d", fs.TotalBytes, fs.UsedBytes)
		}
	})

	t.Run("accepts numeric strings", func(t *testing.T) {
		payload := `{"name":"rootfs","type":"ufs","mountpoint":"/","total-bytes":"5368709120","used-bytes":"2147483648","disk":[{"dev":"/dev/vtbd0p3"}]}`
		var fs VMFileSystem
		if err := json.Unmarshal([]byte(payload), &fs); err != nil {
			t.Fatalf("unexpected error unmarshalling string fields: %v", err)
		}
		if fs.TotalBytes != 5368709120 || fs.UsedBytes != 2147483648 {
			t.Fatalf("unexpected string values: got total=%d used=%d", fs.TotalBytes, fs.UsedBytes)
		}
	})

	t.Run("accepts float-like strings", func(t *testing.T) {
		payload := `{"name":"rootfs","type":"ufs","mountpoint":"/","total-bytes":"1073741824.0","used-bytes":"536870912.0","disk":[{"dev":"/dev/vtbd0p4"}]}`
		var fs VMFileSystem
		if err := json.Unmarshal([]byte(payload), &fs); err != nil {
			t.Fatalf("unexpected error unmarshalling float-like strings: %v", err)
		}
		if fs.TotalBytes != 1073741824 || fs.UsedBytes != 536870912 {
			t.Fatalf("unexpected float string values: got total=%d used=%d", fs.TotalBytes, fs.UsedBytes)
		}
	})
}

func TestMemoryStatusEffectiveAvailable(t *testing.T) {
	t.Run("nil receiver returns zero", func(t *testing.T) {
		var status *MemoryStatus
		if status.EffectiveAvailable() != 0 {
			t.Fatalf("expected nil receiver to return 0")
		}
	})

	tests := []struct {
		name   string
		status MemoryStatus
		want   uint64
	}{
		{
			name:   "uses available field when set",
			status: MemoryStatus{Total: 16 * 1024, Available: 6 * 1024},
			want:   6 * 1024,
		},
		{
			name:   "uses avail field fallback",
			status: MemoryStatus{Total: 16 * 1024, Avail: 5 * 1024},
			want:   5 * 1024,
		},
		{
			name:   "derives from free buffers cached",
			status: MemoryStatus{Total: 32 * 1024, Free: 4 * 1024, Buffers: 2 * 1024, Cached: 6 * 1024},
			want:   12 * 1024,
		},
		{
			name: "available zero but buffers and cache present",
			status: MemoryStatus{
				Total:   64 * 1024,
				Used:    40 * 1024,
				Free:    6 * 1024,
				Buffers: 8 * 1024,
				Cached:  10 * 1024,
			},
			want: 24 * 1024,
		},
		{
			name:   "caps derived value at total",
			status: MemoryStatus{Total: 8 * 1024, Free: 4 * 1024, Buffers: 4 * 1024, Cached: 4 * 1024},
			want:   8 * 1024,
		},
		{
			name:   "returns zero when no data",
			status: MemoryStatus{Total: 24 * 1024},
			want:   0,
		},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			if got := tc.status.EffectiveAvailable(); got != tc.want {
				t.Fatalf("EffectiveAvailable: got %d, want %d", got, tc.want)
			}
		})
	}
}

// TestMemoryStatusEffectiveAvailable_RegressionIssue435 tests the specific scenarios
// reported in GitHub issue #435 where memory calculations incorrectly included cache/buffers
func TestMemoryStatusEffectiveAvailable_RegressionIssue435(t *testing.T) {
	tests := []struct {
		name          string
		status        MemoryStatus
		wantAvailable uint64
		wantUsedPct   float64 // Expected usage percentage when using EffectiveAvailable
		description   string
	}{
		{
			name: "real proxmox 8.x node with available field",
			status: MemoryStatus{
				Total:     16466186240, // 16GB
				Used:      13981696000, // ~14GB (includes cache)
				Free:      1558323200,  // ~1.5GB
				Available: 7422545920,  // ~7GB (cache-aware - this is what we should use!)
				Buffers:   23592960,    // ~23MB
				Cached:    5478891520,  // ~5.4GB
			},
			wantAvailable: 7422545920,
			wantUsedPct:   54.92, // Should be ~55%, not ~85%!
			description:   "Proxmox 8.x returns 'available' field - most accurate",
		},
		{
			name: "older proxmox with avail field",
			status: MemoryStatus{
				Total: 8589934592, // 8GB
				Used:  6871947674, // ~6.4GB (includes cache)
				Free:  805306368,  // ~768MB
				Avail: 3221225472, // ~3GB (cache-aware)
			},
			wantAvailable: 3221225472,
			wantUsedPct:   62.5, // Should be ~62.5%, not ~80%
			description:   "Older Proxmox uses 'avail' field as fallback",
		},
		{
			name: "proxmox without available/avail - derive from components",
			status: MemoryStatus{
				Total:   16777216000, // ~16GB
				Used:    13421772800, // ~12.5GB (includes cache)
				Free:    2147483648,  // 2GB
				Buffers: 536870912,   // 512MB
				Cached:  4294967296,  // 4GB
			},
			wantAvailable: 6979321856, // Free + Buffers + Cached = ~6.5GB
			wantUsedPct:   58.4,       // Should be ~58%, not ~80%
			description:   "When available/avail missing, derive from free+buffers+cached",
		},
		{
			name: "proxmox 8.4 hides cache fields - derive from total-minus-used gap",
			status: MemoryStatus{
				Total:   134794743808, // ~125.6GB
				Used:    107351023616, // ~100GB actual usage
				Free:    6471057408,   // ~6GB bare free reported
				Buffers: 0,
				Cached:  0,
			},
			wantAvailable: 27443720192, // total - used => ~25.6GB reclaimable (free + cache)
			wantUsedPct:   79.6,        // Matches Proxmox node dashboard
			description:   "Proxmox 8.4 stops reporting buffers/cached; use total-used gap to recover cache-aware metric",
		},
		{
			name: "issue #435 specific case - 86% vs 42% real usage",
			status: MemoryStatus{
				Total:     33554432000, // ~32GB
				Used:      28857589760, // ~27GB (includes cache - WRONG!)
				Free:      1073741824,  // 1GB
				Available: 19327352832, // ~18GB (cache-aware - CORRECT!)
			},
			wantAvailable: 19327352832,
			wantUsedPct:   42.4, // Should be ~42%, not 86%!
			description:   "Real user report: 86% shown when actual usage is 42%",
		},
		{
			name: "missing available but buffers/cached still present (issue 553 guard)",
			status: MemoryStatus{
				Total:   34359738368, // 32GB
				Used:    27917287424, // ~26GB reported used (includes cache)
				Free:    2147483648,  // 2GB
				Buffers: 3221225472,  // 3GB
				Cached:  8053063680,  // 7.5GB
			},
			wantAvailable: 13421772800, // Free + Buffers + Cached
			wantUsedPct:   60.94,
			description:   "When available=0 but buffers/cached exist, derive reclaimable memory instead of alerting",
		},
		{
			name: "missing all cache-aware fields - fallback to zero",
			status: MemoryStatus{
				Total: 8589934592,
				Used:  6871947674,
				Free:  0, // All fields missing
			},
			wantAvailable: 1717986918, // Derived from total - used
			wantUsedPct:   80.0,       // Still aligns with cache-inclusive calculation when nothing else reported
			description:   "When all cache fields missing, fall back to total-used gap instead of zero",
		},
	}

	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			got := tc.status.EffectiveAvailable()
			if got != tc.wantAvailable {
				t.Errorf("EffectiveAvailable() = %d, want %d\nScenario: %s",
					got, tc.wantAvailable, tc.description)
			}

			// Calculate what the usage percentage would be with cache-aware calculation
			if tc.wantAvailable > 0 && tc.wantAvailable <= tc.status.Total {
				actualUsed := tc.status.Total - tc.wantAvailable
				usagePct := (float64(actualUsed) / float64(tc.status.Total)) * 100

				// Allow 0.5% tolerance for floating point differences
				if usagePct < tc.wantUsedPct-0.5 || usagePct > tc.wantUsedPct+0.5 {
					t.Errorf("Calculated usage = %.2f%%, want ~%.2f%%\nScenario: %s",
						usagePct, tc.wantUsedPct, tc.description)
				}
			}
		})
	}
}