package app

import (
	"fmt"
	"sort"
	"strings"
	"github.com/seaweedfs/seaweedfs/weed/admin/dash"
	"github.com/seaweedfs/seaweedfs/weed/storage/erasure_coding"
)

templ ClusterEcVolumes(data dash.ClusterEcVolumesData) {
    <div class="d-flex justify-content-between flex-wrap flex-md-nowrap align-items-center pt-3 pb-2 mb-3 border-bottom">
        <div>
            <h1 class="h2">
                <i class="fas fa-database me-2"></i>EC Volumes
            </h1>
            if data.Collection != "" {
                <div class="d-flex align-items-center mt-2">
                    if data.Collection == "default" {
                        <span class="badge bg-secondary text-white me-2">
                            <i class="fas fa-filter me-1"></i>Collection: default
                        </span>
                    } else {
                        <span class="badge bg-info text-white me-2">
                            <i class="fas fa-filter me-1"></i>Collection: {data.Collection}
                        </span>
                    }
                    <a href={ dash.PUrl(ctx, "/storage/ec-volumes") } class="btn btn-sm btn-outline-secondary">
                        <i class="fas fa-times me-1"></i>Clear Filter
                    </a>
                </div>
            }
        </div>
        <div class="btn-toolbar mb-2 mb-md-0">
            <div class="btn-group me-2">
                <select class="form-select form-select-sm me-2" id="pageSizeSelect" onchange="changePageSize(this.value)" style="width: auto;">
                    <option value="5" if data.PageSize == 5 { selected="selected" }>5 per page</option>
                    <option value="10" if data.PageSize == 10 { selected="selected" }>10 per page</option>
                    <option value="25" if data.PageSize == 25 { selected="selected" }>25 per page</option>
                    <option value="50" if data.PageSize == 50 { selected="selected" }>50 per page</option>
                    <option value="100" if data.PageSize == 100 { selected="selected" }>100 per page</option>
                </select>
                <button type="button" class="btn btn-sm btn-outline-primary" onclick="window.location.reload()">
                    <i class="fas fa-refresh me-1"></i>Refresh
                </button>
            </div>
        </div>
    </div>

    <!-- Statistics Cards -->
    <div class="row mb-4">
        <div class="col-md-3">
            <div class="card text-bg-primary">
                <div class="card-body">
                    <div class="d-flex justify-content-between">
                        <div>
                            <h6 class="card-title">Total Volumes</h6>
                            <h4 class="mb-0">{fmt.Sprintf("%d", data.TotalVolumes)}</h4>
                        </div>
                        <div class="align-self-center">
                            <i class="fas fa-cubes fa-2x"></i>
                        </div>
                    </div>
                </div>
            </div>
        </div>
        <div class="col-md-3">
            <div class="card text-bg-info">
                <div class="card-body">
                    <div class="d-flex justify-content-between">
                        <div>
                            <h6 class="card-title">Total Shards</h6>
                            <h4 class="mb-0">{fmt.Sprintf("%d", data.TotalShards)}</h4>
                        </div>
                        <div class="align-self-center">
                            <i class="fas fa-puzzle-piece fa-2x"></i>
                        </div>
                    </div>
                </div>
            </div>
        </div>
        <div class="col-md-3">
            <div class="card text-bg-success">
                <div class="card-body">
                    <div class="d-flex justify-content-between">
                        <div>
                            <h6 class="card-title">Healthy Volumes</h6>
                            <h4 class="mb-0">{fmt.Sprintf("%d", data.CompleteVolumes)}</h4>
                            <small>All { fmt.Sprintf("%d", erasure_coding.TotalShardsCount) } shards present</small>
                        </div>
                        <div class="align-self-center">
                            <i class="fas fa-check-circle fa-2x"></i>
                        </div>
                    </div>
                </div>
            </div>
        </div>
        <div class="col-md-3">
            <div class="card text-bg-warning">
                <div class="card-body">
                    <div class="d-flex justify-content-between">
                        <div>
                            <h6 class="card-title">Degraded Volumes</h6>
                            <h4 class="mb-0">{fmt.Sprintf("%d", data.IncompleteVolumes)}</h4>
                            <small>Incomplete/Critical</small>
                        </div>
                        <div class="align-self-center">
                            <i class="fas fa-exclamation-triangle fa-2x"></i>
                        </div>
                    </div>
                </div>
            </div>
        </div>
    </div>

    <!-- EC Storage Information Note -->
    <div class="alert alert-info mb-4" role="alert">
        <i class="fas fa-info-circle me-2"></i>
        <strong>EC Storage Note:</strong> 
        EC volumes use erasure coding ({ fmt.Sprintf("%d+%d", erasure_coding.DataShardsCount, erasure_coding.ParityShardsCount) }) which stores data across { fmt.Sprintf("%d", erasure_coding.TotalShardsCount) } shards with redundancy. 
        Physical storage is approximately { fmt.Sprintf("%.1fx", float64(erasure_coding.TotalShardsCount)/float64(erasure_coding.DataShardsCount)) } the original logical data size due to { fmt.Sprintf("%d", erasure_coding.ParityShardsCount) } parity shards.
    </div>

    <!-- Volumes Table -->
    <div class="table-responsive">
        <table class="table table-striped table-hover" id="ecVolumesTable">
            <thead>
                <tr>
                    <th>
                        <a href="#" onclick="sortBy('volume_id')" class="text-dark text-decoration-none">
                            Volume ID
                            if data.SortBy == "volume_id" {
                                if data.SortOrder == "asc" {
                                    <i class="fas fa-sort-up ms-1"></i>
                                } else {
                                    <i class="fas fa-sort-down ms-1"></i>
                                }
                            } else {
                                <i class="fas fa-sort ms-1 text-muted"></i>
                            }
                        </a>
                    </th>
                    if data.ShowCollectionColumn {
                        <th>
                            <a href="#" onclick="sortBy('collection')" class="text-dark text-decoration-none">
                                Collection
                                if data.SortBy == "collection" {
                                    if data.SortOrder == "asc" {
                                        <i class="fas fa-sort-up ms-1"></i>
                                    } else {
                                        <i class="fas fa-sort-down ms-1"></i>
                                    }
                                } else {
                                    <i class="fas fa-sort ms-1 text-muted"></i>
                                }
                            </a>
                        </th>
                    }
                    <th>
                        <a href="#" onclick="sortBy('total_shards')" class="text-dark text-decoration-none">
                            Shard Count
                            if data.SortBy == "total_shards" {
                                if data.SortOrder == "asc" {
                                    <i class="fas fa-sort-up ms-1"></i>
                                } else {
                                    <i class="fas fa-sort-down ms-1"></i>
                                }
                            } else {
                                <i class="fas fa-sort ms-1 text-muted"></i>
                            }
                        </a>
                    </th>
                    <th class="text-dark">Shard Size</th>
                    <th class="text-dark">Shard Locations</th>
                    <th>
                        <a href="#" onclick="sortBy('completeness')" class="text-dark text-decoration-none">
                            Status
                            if data.SortBy == "completeness" {
                                if data.SortOrder == "asc" {
                                    <i class="fas fa-sort-up ms-1"></i>
                                } else {
                                    <i class="fas fa-sort-down ms-1"></i>
                                }
                            } else {
                                <i class="fas fa-sort ms-1 text-muted"></i>
                            }
                        </a>
                    </th>
                    if data.ShowDataCenterColumn {
                        <th class="text-dark">Data Centers</th>
                    }
                    <th class="text-dark">Actions</th>
                </tr>
            </thead>
            <tbody>
                for _, volume := range data.EcVolumes {
                    <tr>
                        <td>
                            <span class="fw-bold">{fmt.Sprintf("%d", volume.VolumeID)}</span>
                        </td>
                        if data.ShowCollectionColumn {
                            <td>
                                if volume.Collection != "" {
                                    <a href={ dash.PUrl(ctx, fmt.Sprintf("/storage/ec-shards?collection=%s", volume.Collection)) } class="text-decoration-none">
                                        <span class="badge bg-info text-white">{volume.Collection}</span>
                                    </a>
                                } else {
                                    <a href={ dash.PUrl(ctx, "/storage/ec-shards?collection=default") } class="text-decoration-none">
                                        <span class="badge bg-secondary text-white">default</span>
                                    </a>
                                }
                            </td>
                        }
                        <td>
                            <span class="badge bg-primary">{fmt.Sprintf("%d/%d", volume.TotalShards, erasure_coding.TotalShardsCount)}</span>
                        </td>
                        <td>
                            @displayShardSizes(volume.ShardSizes)
                        </td>
                        <td>
                            @displayVolumeDistribution(volume)
                        </td>
                        <td>
                            @displayEcVolumeStatus(volume)
                        </td>
                        if data.ShowDataCenterColumn {
                            <td>
                                for i, dc := range volume.DataCenters {
                                    if i > 0 {
                                        <span>, </span>
                                    }
                                    <span class="badge bg-primary text-white">{dc}</span>
                                }
                            </td>
                        }
                        <td>
                            <div class="btn-group" role="group">
                                <button type="button" class="btn btn-sm btn-outline-primary" 
                                        onclick="showVolumeDetails(event)" 
                                        data-volume-id={ fmt.Sprintf("%d", volume.VolumeID) }
                                        title="View EC volume details">
                                    <i class="fas fa-info-circle"></i>
                                </button>
                                if !volume.IsComplete {
                                    <button type="button" class="btn btn-sm btn-outline-warning" 
                                            onclick="repairVolume(event)" 
                                            data-volume-id={ fmt.Sprintf("%d", volume.VolumeID) }
                                            title="Repair missing shards">
                                        <i class="fas fa-wrench"></i>
                                    </button>
                                }
                            </div>
                        </td>
                    </tr>
                }
            </tbody>
        </table>
    </div>

    <!-- Pagination -->
    if data.TotalPages > 1 {
        <nav aria-label="EC Volumes pagination">
            <ul class="pagination justify-content-center">
                if data.Page > 1 {
                    <li class="page-item">
                        <a class="page-link" href="#" onclick="goToPage(event)" data-page="1">
                            <i class="fas fa-angle-double-left"></i>
                        </a>
                    </li>
                    <li class="page-item">
                        <a class="page-link" href="#" onclick="goToPage(event)" data-page={ fmt.Sprintf("%d", data.Page-1) }>
                            <i class="fas fa-chevron-left"></i>
                        </a>
                    </li>
                }
                
                <!-- First page -->
                if data.Page > 3 {
                    <li class="page-item">
                        <a class="page-link" href="#" onclick="goToPage(event)" data-page="1">1</a>
                    </li>
                    if data.Page > 4 {
                        <li class="page-item disabled">
                            <span class="page-link">...</span>
                        </li>
                    }
                }
                
                <!-- Current page neighbors -->
                if data.Page > 1 {
                    <li class="page-item">
                        <a class="page-link" href="#" onclick="goToPage(event)" data-page={ fmt.Sprintf("%d", data.Page-1) }>{fmt.Sprintf("%d", data.Page-1)}</a>
                    </li>
                }
                
                <li class="page-item active">
                    <span class="page-link">{fmt.Sprintf("%d", data.Page)}</span>
                </li>
                
                if data.Page < data.TotalPages {
                    <li class="page-item">
                        <a class="page-link" href="#" onclick="goToPage(event)" data-page={ fmt.Sprintf("%d", data.Page+1) }>{fmt.Sprintf("%d", data.Page+1)}</a>
                    </li>
                }
                
                <!-- Last page -->
                if data.Page < data.TotalPages-2 {
                    if data.Page < data.TotalPages-3 {
                        <li class="page-item disabled">
                            <span class="page-link">...</span>
                        </li>
                    }
                    <li class="page-item">
                        <a class="page-link" href="#" onclick="goToPage(event)" data-page={ fmt.Sprintf("%d", data.TotalPages) }>{fmt.Sprintf("%d", data.TotalPages)}</a>
                    </li>
                }
                
                if data.Page < data.TotalPages {
                    <li class="page-item">
                        <a class="page-link" href="#" onclick="goToPage(event)" data-page={ fmt.Sprintf("%d", data.Page+1) }>
                            <i class="fas fa-chevron-right"></i>
                        </a>
                    </li>
                    <li class="page-item">
                        <a class="page-link" href="#" onclick="goToPage(event)" data-page={ fmt.Sprintf("%d", data.TotalPages) }>
                            <i class="fas fa-angle-double-right"></i>
                        </a>
                    </li>
                }
            </ul>
        </nav>
    }

    <!-- JavaScript -->
    <script>
        function sortBy(field) {
            const currentSort = new URLSearchParams(window.location.search).get('sort_by');
            const currentOrder = new URLSearchParams(window.location.search).get('sort_order') || 'asc';
            
            let newOrder = 'asc';
            if (currentSort === field && currentOrder === 'asc') {
                newOrder = 'desc';
            }
            
            updateUrl({
                sort_by: field,
                sort_order: newOrder,
                page: 1
            });
        }

        function goToPage(event) {
            event.preventDefault();
            const page = event.target.closest('a').getAttribute('data-page');
            updateUrl({ page: page });
        }

        function changePageSize(newPageSize) {
            updateUrl({ page_size: newPageSize, page: 1 });
        }

        function updateUrl(params) {
            const url = new URL(window.location);
            Object.keys(params).forEach(key => {
                if (params[key] != null) {
                    url.searchParams.set(key, params[key]);
                } else {
                    url.searchParams.delete(key);
                }
            });
            window.location.href = url.toString();
        }

        function showVolumeDetails(event) {
            const volumeId = event.target.closest('button').getAttribute('data-volume-id');
            window.location.href = (window.__BASE_PATH__ || '') + `/storage/ec-volumes/${volumeId}`;
        }

        function repairVolume(event) {
            const volumeId = event.target.closest('button').getAttribute('data-volume-id');
            showConfirm(`Are you sure you want to repair missing shards for volume ${volumeId}?`, function() {
                fetch((window.__BASE_PATH__ || '') + `/api/storage/ec-volumes/${volumeId}/repair`, {
                    method: 'POST',
                    headers: {
                        'Content-Type': 'application/json',
                    }
                })
                .then(response => {
                    if (!response.ok) {
                        throw new Error(`HTTP ${response.status}: ${response.statusText}`);
                    }
                    return response.json();
                })
                .then(data => {
                    if (data && data.success) {
                        showAlert('Repair initiated successfully', 'success');
                        location.reload();
                    } else {
                        showAlert('Failed to initiate repair: ' + (data && data.error ? data.error : 'Unknown error'), 'error');
                    }
                })
                .catch(error => {
                    showAlert('Error: ' + error.message, 'error');
                });
            });
        }
    </script>
}

// displayShardSizes renders shard sizes in a compact format
templ displayShardSizes(shardSizes map[int]int64) {
	if len(shardSizes) == 0 {
		<span class="text-muted">-</span>
	} else {
		@renderShardSizesContent(shardSizes)
	}
}

// renderShardSizesContent renders the content of shard sizes
templ renderShardSizesContent(shardSizes map[int]int64) {
	if areAllShardSizesSame(shardSizes) {
		// All shards have the same size, show just the common size
		<span class="text-success">{getCommonShardSize(shardSizes)}</span>
	} else {
		// Shards have different sizes, show individual sizes
		<div class="shard-sizes" style="max-width: 300px;">
			{ formatIndividualShardSizes(shardSizes) }
		</div>
	}
}

// ServerShardInfo represents server and its shard ranges with sizes
type ServerShardInfo struct {
	Server      string
	ShardRanges string
}

// groupShardsByServer groups shards by server and formats ranges
func groupShardsByServer(shardLocations map[int]string) []ServerShardInfo {
	if len(shardLocations) == 0 {
		return []ServerShardInfo{}
	}

	// Group shards by server
	serverShards := make(map[string][]int)
	for shardId, server := range shardLocations {
		serverShards[server] = append(serverShards[server], shardId)
	}

	var serverInfos []ServerShardInfo
	for server, shards := range serverShards {
		// Sort shards for each server
		sort.Ints(shards)
		
		// Format shard ranges compactly
		shardRanges := formatShardRanges(shards)
		serverInfos = append(serverInfos, ServerShardInfo{
			Server:      server,
			ShardRanges: shardRanges,
		})
	}

	// Sort by server name
	sort.Slice(serverInfos, func(i, j int) bool {
		return serverInfos[i].Server < serverInfos[j].Server
	})

	return serverInfos
}

// Helper function to format shard ranges compactly (e.g., "0-3,7,9-11")
func formatShardRanges(shards []int) string {
	if len(shards) == 0 {
		return ""
	}

	var ranges []string
	start := shards[0]
	end := shards[0]

	for i := 1; i < len(shards); i++ {
		if shards[i] == end+1 {
			end = shards[i]
		} else {
			if start == end {
				ranges = append(ranges, fmt.Sprintf("%d", start))
			} else {
				ranges = append(ranges, fmt.Sprintf("%d-%d", start, end))
			}
			start = shards[i]
			end = shards[i]
		}
	}

	// Add the last range
	if start == end {
		ranges = append(ranges, fmt.Sprintf("%d", start))
	} else {
		ranges = append(ranges, fmt.Sprintf("%d-%d", start, end))
	}

	return strings.Join(ranges, ",")
}

// Helper function to convert bytes to human readable format
func bytesToHumanReadable(bytes int64) string {
	const unit = 1024
	if bytes < unit {
		return fmt.Sprintf("%dB", bytes)
	}
	div, exp := int64(unit), 0
	for n := bytes / unit; n >= unit; n /= unit {
		div *= unit
		exp++
	}
	return fmt.Sprintf("%.1f%cB", float64(bytes)/float64(div), "KMGTPE"[exp])
}

// Helper function to format missing shards
func formatMissingShards(missingShards []int) string {
	if len(missingShards) == 0 {
		return ""
	}
	
	var shardStrs []string
	for _, shard := range missingShards {
		shardStrs = append(shardStrs, fmt.Sprintf("%d", shard))
	}
	
	return strings.Join(shardStrs, ", ")
}

// Helper function to check if all shard sizes are the same
func areAllShardSizesSame(shardSizes map[int]int64) bool {
	if len(shardSizes) <= 1 {
		return true
	}
	
	var firstSize int64 = -1
	for _, size := range shardSizes {
		if firstSize == -1 {
			firstSize = size
		} else if size != firstSize {
			return false
		}
	}
	return true
}

// Helper function to get the common shard size (when all shards are the same size)
func getCommonShardSize(shardSizes map[int]int64) string {
	for _, size := range shardSizes {
		return bytesToHumanReadable(size)
	}
	return "-"
}

// Helper function to format individual shard sizes
func formatIndividualShardSizes(shardSizes map[int]int64) string {
	if len(shardSizes) == 0 {
		return ""
	}
	
	// Group shards by size for more compact display
	sizeGroups := make(map[int64][]int)
	for shardId, size := range shardSizes {
		sizeGroups[size] = append(sizeGroups[size], shardId)
	}
	
	// If there are only 1-2 different sizes, show them grouped
	if len(sizeGroups) <= 3 {
		var groupStrs []string
		for size, shardIds := range sizeGroups {
			// Sort shard IDs
			sort.Ints(shardIds)
			
			var idRanges []string
			if len(shardIds) <= erasure_coding.ParityShardsCount {
				// Show individual IDs if few shards
				for _, id := range shardIds {
					idRanges = append(idRanges, fmt.Sprintf("%d", id))
				}
			} else {
				// Show count if many shards
				idRanges = append(idRanges, fmt.Sprintf("%d shards", len(shardIds)))
			}
			groupStrs = append(groupStrs, fmt.Sprintf("%s: %s", strings.Join(idRanges, ","), bytesToHumanReadable(size)))
		}
		return strings.Join(groupStrs, " | ")
	}
	
	// If too many different sizes, show summary
	return fmt.Sprintf("%d different sizes", len(sizeGroups))
}

// displayVolumeDistribution shows the distribution summary for a volume
templ displayVolumeDistribution(volume dash.EcVolumeWithShards) {
    <div class="small">
        <i class="fas fa-sitemap me-1"></i>
        { calculateVolumeDistributionSummary(volume) }
    </div>
}

// displayEcVolumeStatus shows an improved status display for EC volumes.
// Status thresholds are based on EC recovery capability:
// - Critical: More than DataShardsCount missing (data is unrecoverable)
// - Degraded: More than half of DataShardsCount missing (high risk)
// - Incomplete: More than half of ParityShardsCount missing (reduced redundancy)
// - Minor Issues: Few shards missing (still fully recoverable)
templ displayEcVolumeStatus(volume dash.EcVolumeWithShards) {
    if volume.IsComplete {
        <span class="badge bg-success"><i class="fas fa-check me-1"></i>Complete</span>
    } else {
        if len(volume.MissingShards) > erasure_coding.DataShardsCount {
            // Unrecoverable: more shards missing than EC can reconstruct
            <span class="badge bg-danger"><i class="fas fa-skull me-1"></i>Critical ({fmt.Sprintf("%d", len(volume.MissingShards))} missing)</span>
        } else if len(volume.MissingShards) > (erasure_coding.DataShardsCount/2) {
            // High risk: approaching unrecoverable state
            <span class="badge bg-warning"><i class="fas fa-exclamation-triangle me-1"></i>Degraded ({fmt.Sprintf("%d", len(volume.MissingShards))} missing)</span>
        } else if len(volume.MissingShards) > (erasure_coding.ParityShardsCount/2) {
            // Reduced redundancy but still recoverable
            <span class="badge bg-warning"><i class="fas fa-info-circle me-1"></i>Incomplete ({fmt.Sprintf("%d", len(volume.MissingShards))} missing)</span>
        } else {
            // Minor: few shards missing, fully recoverable with good margin
            <span class="badge bg-info"><i class="fas fa-info-circle me-1"></i>Minor Issues ({fmt.Sprintf("%d", len(volume.MissingShards))} missing)</span>
        }
    }
}

// calculateVolumeDistributionSummary calculates and formats the distribution summary for a volume
func calculateVolumeDistributionSummary(volume dash.EcVolumeWithShards) string {
    dataCenters := make(map[string]bool)
    racks := make(map[string]bool)
    servers := make(map[string]bool)
    
    // Count unique servers from shard locations
    for _, server := range volume.ShardLocations {
        servers[server] = true
    }
    
    // Use the DataCenters field if available
    for _, dc := range volume.DataCenters {
        dataCenters[dc] = true
    }
    
    // Use the Servers field if available
    for _, server := range volume.Servers {
        servers[server] = true
    }
    
    // Use the Racks field if available
    for _, rack := range volume.Racks {
        racks[rack] = true
    }
    
    // If we don't have rack information, estimate it from servers as fallback
    rackCount := len(racks)
    if rackCount == 0 {
        // Fallback estimation - assume each server might be in a different rack
        rackCount = len(servers)
        if len(dataCenters) > 0 {
            // More conservative estimate if we have DC info
            rackCount = (len(servers) + len(dataCenters) - 1) / len(dataCenters)
            if rackCount == 0 {
                rackCount = 1
            }
        }
    }
    
    return fmt.Sprintf("%d DCs, %d racks, %d servers", len(dataCenters), rackCount, len(servers))
} 