astralis/examples/EnumerableOperations.vala

using Astralis;
using Invercargill;
using Invercargill.DataStructures;

/**
 * EnumerableOperations Example
 * 
 * Demonstrates various LINQ-like operations available in Invercargill Enumerable.
 * This example shows filtering, mapping, grouping, and aggregation operations.
 */
void main() {
    var router = new Router();
    var server = new Server(8087, router);
    
    // Root endpoint
    router.map_func("/", (context) => {
        return new BufferedHttpResult.from_string(
            """Enumerable Operations Demo

This example demonstrates various LINQ-like operations available in Invercargill Enumerable:

Endpoints:
  GET /filter                - Filtering examples
  GET /map                   - Mapping/Projection examples
  GET /group-by              - Grouping examples
  GET /aggregate              - Aggregation examples
  GET /sort                  - Sorting examples
  GET /set-operations        - Set operations (union, intersection, etc.)
  GET /advanced               - Advanced operations (zip, partition, etc.)
"""
        );
    });
    
    // Filtering examples
    router.map_func("/filter", (context) => {
        var numbers = Wrap.array<int>({1, 2, 3, 4, 5, 6, 7, 8, 9, 10});
        
        var parts = new Series<string>();
        parts.add_start("Original: ");
        parts.add_start(enumerable_int_to_string(numbers.as_enumerable()));
        parts.add_start("\n\n");
        
        // Filter even numbers
        var even = numbers.as_enumerable()
            .where(n => n % 2 == 0);
        parts.add_start("Even numbers: ");
        parts.add_start(enumerable_int_to_string(even));
        parts.add_start("\n");
        
        // Filter odd numbers
        var odd = numbers.as_enumerable()
            .where(n => n % 2 != 0);
        parts.add_start("Odd numbers: ");
        parts.add_start(enumerable_int_to_string(odd));
        parts.add_start("\n");
        
        // Filter numbers greater than 5
        var greater_than_5 = numbers.as_enumerable()
            .where(n => n > 5);
        parts.add_start("Greater than 5: ");
        parts.add_start(enumerable_int_to_string(greater_than_5));
        parts.add_start("\n\n");
        
        // Chained filters
        var filtered = numbers.as_enumerable()
            .where(n => n > 3)
            .where(n => n < 8);
        parts.add_start("Between 3 and 8: ");
        parts.add_start(enumerable_int_to_string(filtered));
        
        var result = parts.to_immutable_buffer()
            .aggregate<string>("", (acc, s) => acc + s);
        
        return new BufferedHttpResult.from_string(result);
    });
    
    // Mapping/Projection examples
    router.map_func("/map", (context) => {
        var numbers = Wrap.array<int>({1, 2, 3, 4, 5});
        
        var parts = new Series<string>();
        parts.add_start("Original: ");
        parts.add_start(enumerable_int_to_string(numbers.as_enumerable()));
        parts.add_start("\n\n");
        
        // Square each number
        var squared = numbers.as_enumerable()
            .select<int>(n => n * n);
        parts.add_start("Squared: ");
        parts.add_start(enumerable_int_to_string(squared));
        parts.add_start("\n");
        
        // Double each number
        var doubled = numbers.as_enumerable()
            .select<int>(n => n * 2);
        parts.add_start("Doubled: ");
        parts.add_start(enumerable_int_to_string(doubled));
        parts.add_start("\n");
        
        // Convert to string
        var as_strings = numbers.as_enumerable()
            .select<string>(n => n.to_string());
        parts.add_start("As strings: ");
        parts.add_start(enumerable_string_to_string(as_strings));
        parts.add_start("\n\n");
        
        // With index
        var with_index = numbers.as_enumerable()
            .with_positions()
            .select<string>(pair => @"$(pair.item) at index $(pair.position)");
        parts.add_start("With index: ");
        parts.add_start(enumerable_string_to_string(with_index));
        
        var result = parts.to_immutable_buffer()
            .aggregate<string>("", (acc, s) => acc + s);
        
        return new BufferedHttpResult.from_string(result);
    });
    
    // Grouping examples
    router.map_func("/group-by", (context) => {
        var words = Wrap.array<string>({
            "apple", "banana", "cherry", "apricot", 
            "blueberry", "blackberry", "coconut"
        });
        
        var parts = new Series<string>();
        parts.add_start("Words: ");
        parts.add_start(enumerable_string_to_string(words.as_enumerable()));
        parts.add_start("\n\n");
        
        // Group by first letter
        var grouped = words.as_enumerable()
            .group_by<string>(w => w.get_char(0).to_string());
        
        parts.add_start("Grouped by first letter:\n");
        grouped.iterate((grouping) => {
            parts.add_start(@"  $(grouping.key): ");
            parts.add_start(enumerable_string_to_string(grouping.to_immutable_buffer()));
            parts.add_start("\n");
        });
        
        var result = parts.to_immutable_buffer()
            .aggregate<string>("", (acc, s) => acc + s);
        
        return new BufferedHttpResult.from_string(result);
    });
    
    // Aggregation examples
    router.map_func("/aggregate", (context) => {
        var numbers = Wrap.array<int>({1, 2, 3, 4, 5, 6, 7, 8, 9, 10});
        
        var parts = new Series<string>();
        parts.add_start("Numbers: ");
        parts.add_start(enumerable_int_to_string(numbers.as_enumerable()));
        parts.add_start("\n\n");
        
        // Count
        var count = numbers.as_enumerable().count();
        parts.add_start(@"Count: $count\n");
        
        // Sum using aggregate
        var sum = numbers.as_enumerable()
            .aggregate<int>(0, (acc, n) => acc + n);
        parts.add_start(@"Sum: $sum\n");
        
        // Average
        var avg = (double)sum / count;
        parts.add_start(@"Average: $avg\n");
        
        // Min
        var min = numbers.as_enumerable().min(n => n);
        parts.add_start(@"Min: $min\n");
        
        // Max
        var max = numbers.as_enumerable().max(n => n);
        parts.add_start(@"Max: $max\n");
        
        // First
        var first = numbers.as_enumerable().first();
        parts.add_start(@"First: $first\n");
        
        // Last
        var last = numbers.as_enumerable().last();
        parts.add_start(@"Last: $last\n");
        
        var result = parts.to_immutable_buffer()
            .aggregate<string>("", (acc, s) => acc + s);
        
        return new BufferedHttpResult.from_string(result);
    });
    
    // Sorting examples
    router.map_func("/sort", (context) => {
        var numbers = Wrap.array<int>({5, 2, 8, 1, 9, 3, 7, 4, 6, 10});
        
        var parts = new Series<string>();
        parts.add_start("Original: ");
        parts.add_start(enumerable_int_to_string(numbers.as_enumerable()));
        parts.add_start("\n\n");
        
        // Sort ascending
        var sorted_asc = numbers.as_enumerable()
            .order_by<int>(n => n);
        parts.add_start("Ascending: ");
        parts.add_start(enumerable_int_to_string(sorted_asc));
        parts.add_start("\n");
        
        // Sort descending
        var sorted_desc = numbers.as_enumerable()
            .order_by_descending<int>(n => n);
        parts.add_start("Descending: ");
        parts.add_start(enumerable_int_to_string(sorted_desc));
        
        var result = parts.to_immutable_buffer()
            .aggregate<string>("", (acc, s) => acc + s);
        
        return new BufferedHttpResult.from_string(result);
    });
    
    // Set operations
    router.map_func("/set-operations", (context) => {
        var set1 = Wrap.array<int>({1, 2, 3, 4, 5});
        var set2 = Wrap.array<int>({4, 5, 6, 7, 8});
        
        var parts = new Series<string>();
        parts.add_start("Set 1: ");
        parts.add_start(enumerable_int_to_string(set1.as_enumerable()));
        parts.add_start("\n");
        parts.add_start("Set 2: ");
        parts.add_start(enumerable_int_to_string(set2.as_enumerable()));
        parts.add_start("\n\n");
        
        // Union (concat)
        var union = set1.as_enumerable().concat(set2.as_enumerable());
        parts.add_start("Union: ");
        parts.add_start(enumerable_int_to_string(union));
        parts.add_start("\n");
        
        // Common (intersection)
        var common = set1.as_enumerable().common(set2.as_enumerable());
        parts.add_start("Common: ");
        parts.add_start(enumerable_int_to_string(common));
        parts.add_start("\n");
        
        // Non-common (difference)
        var diff = set1.as_enumerable().non_common(set2.as_enumerable());
        parts.add_start("In set1 but not set2: ");
        parts.add_start(enumerable_int_to_string(diff));
        
        var result = parts.to_immutable_buffer()
            .aggregate<string>("", (acc, s) => acc + s);
        
        return new BufferedHttpResult.from_string(result);
    });
    
    // Advanced operations
    router.map_func("/advanced", (context) => {
        var numbers = Wrap.array<int>({1, 2, 3, 4, 5});
        
        var parts = new Series<string>();
        
        // Take
        var taken = numbers.as_enumerable().take(3);
        parts.add_start("Take 3: ");
        parts.add_start(enumerable_int_to_string(taken));
        parts.add_start("\n");
        
        // Skip
        var skipped = numbers.as_enumerable().skip(2);
        parts.add_start("Skip 2: ");
        parts.add_start(enumerable_int_to_string(skipped));
        parts.add_start("\n");
        
        // Distinct
        var with_dupes = Wrap.array<int>({1, 2, 2, 3, 3, 3, 4});
        var distinct = with_dupes.as_enumerable().distinct();
        parts.add_start("Distinct from {1,2,2,3,3,3,4}: ");
        parts.add_start(enumerable_int_to_string(distinct));
        parts.add_start("\n");
        
        // Reverse
        var reversed = numbers.as_enumerable().reverse();
        parts.add_start("Reversed: ");
        parts.add_start(enumerable_int_to_string(reversed));
        
        var result = parts.to_immutable_buffer()
            .aggregate<string>("", (acc, s) => acc + s);
        
        return new BufferedHttpResult.from_string(result);
    });
    
    print("Enumerable Operations Demo Server running on port 8087\n");
    print("Try these endpoints:\n");
    print("  - http://localhost:8087/\n");
    print("  - http://localhost:8087/filter\n");
    print("  - http://localhost:8087/map\n");
    print("  - http://localhost:8087/group-by\n");
    print("  - http://localhost:8087/aggregate\n");
    print("  - http://localhost:8087/sort\n");
    print("  - http://localhost:8087/set-operations\n");
    print("  - http://localhost:8087/advanced\n");
    
    server.run();
}

// Helper functions

string enumerable_int_to_string(Enumerable<int> enumerable) {
    return enumerable.to_immutable_buffer()
        .aggregate<string>("[", (acc, n) => {
            if (acc == "[") return acc + n.to_string();
            return acc + ", " + n.to_string();
        }) + "]";
}

string enumerable_string_to_string(Enumerable<string> enumerable) {
    return enumerable.to_immutable_buffer()
        .aggregate<string>("[", (acc, s) => {
            if (acc == "[") return acc + "\"" + s + "\"";
            return acc + ", \"" + s + "\"";
        }) + "]";
}