datalogic-rs 5.0.0

//! Example demonstrating the structured-objects (templating) feature.
//!
//! When templating mode is enabled, Engine treats unknown keys as
//! literal output fields rather than operators. This enables JSON templating
//! where the output structure mirrors the input template.
//!
//! Uses the v5 string-based API ([`Engine::evaluate_str`]) — no
//! `serde_json::Value` boundary, no `compat` feature required.

use datalogic_rs::Engine;

fn main() {
    println!("Structured Objects (templating) Examples\n");
    println!("=========================================\n");

    let engine = Engine::builder().with_templating(true).build();

    // Example 1: Basic object template
    println!("1. Basic Object Template");
    println!("------------------------");

    let template = r#"{
        "name": {"var": "user.name"},
        "email": {"var": "user.email"},
        "active": true
    }"#;
    let data = r#"{
        "user": {
            "name": "Alice Johnson",
            "email": "alice@example.com"
        }
    }"#;

    let result = engine.eval_str(template, data).unwrap();
    println!("   Template: {}", template);
    println!("   Result:   {}\n", result);

    // Example 2: Nested object structures
    println!("2. Nested Object Structures");
    println!("---------------------------");

    let template = r#"{
        "profile": {
            "firstName": {"var": "first"},
            "lastName": {"var": "last"},
            "fullName": {"cat": [{"var": "first"}, " ", {"var": "last"}]}
        },
        "metadata": {
            "createdAt": {"var": "timestamp"},
            "version": "1.0"
        }
    }"#;
    let data = r#"{
        "first": "John",
        "last": "Doe",
        "timestamp": "2024-01-15T10:30:00Z"
    }"#;

    let result = engine.eval_str(template, data).unwrap();
    println!("   Result: {}\n", result);

    // Example 3: Conditional fields — compile once, evaluate against multiple
    // payloads via the reusable `Session` handle.
    println!("3. Conditional Fields");
    println!("---------------------");

    let template = r#"{
        "status": {"if": [
            {"var": "isActive"},
            "active",
            "inactive"
        ]},
        "tier": {"if": [
            {">": [{"var": "points"}, 1000]}, "gold",
            {"if": [
                {">": [{"var": "points"}, 500]}, "silver",
                "bronze"
            ]}
        ]},
        "points": {"var": "points"}
    }"#;

    let compiled = engine.compile(template).unwrap();
    let mut session = engine.session();

    let result1 = session
        .eval_str(&compiled, r#"{"isActive": true, "points": 1500}"#)
        .unwrap();
    println!("   User with 1500 points: {}", result1);

    let result2 = session
        .eval_str(&compiled, r#"{"isActive": false, "points": 750}"#)
        .unwrap();
    println!("   User with 750 points:  {}\n", result2);

    // Example 4: Arrays with mapped content
    println!("4. Arrays with Mapped Content");
    println!("-----------------------------");

    let template = r#"{
        "items": {"map": [
            {"var": "products"},
            {
                "id": {"var": ".id"},
                "displayName": {"cat": [{"var": ".name"}, " ($", {"var": ".price"}, ")"]},
                "inStock": {">": [{"var": ".quantity"}, 0]}
            }
        ]},
        "totalProducts": {"length": {"var": "products"}}
    }"#;
    let data = r#"{
        "products": [
            {"id": 1, "name": "Widget", "price": 9.99, "quantity": 50},
            {"id": 2, "name": "Gadget", "price": 19.99, "quantity": 0},
            {"id": 3, "name": "Gizmo", "price": 14.99, "quantity": 25}
        ]
    }"#;

    let result = engine.eval_str(template, data).unwrap();
    println!("   Result: {}\n", result);

    // Example 5: API response transformation
    println!("5. API Response Transformation");
    println!("------------------------------");

    let template = r#"{
        "success": true,
        "data": {
            "user": {
                "id": {"var": "userId"},
                "displayName": {"var": "name"},
                "role": {"if": [
                    {"var": "isAdmin"},
                    "administrator",
                    "user"
                ]}
            },
            "permissions": {"filter": [
                {"var": "allPermissions"},
                {"var": ".enabled"}
            ]}
        },
        "timestamp": {"now": []}
    }"#;
    let data = r#"{
        "userId": "usr_12345",
        "name": "Jane Smith",
        "isAdmin": true,
        "allPermissions": [
            {"name": "read", "enabled": true},
            {"name": "write", "enabled": true},
            {"name": "delete", "enabled": false}
        ]
    }"#;

    let result = engine.eval_str(template, data).unwrap();
    println!("   Result: {}\n", result);

    // Example 6: Comparing with vs without templating
    println!("6. With vs Without templating");
    println!("------------------------------");

    let standard_engine = Engine::new();
    let templating_engine = Engine::builder().with_templating(true).build();

    let template = r#"{
        "result": {"var": "x"},
        "label": "Output"
    }"#;
    let data = r#"{"x": 42}"#;

    let standard_result = standard_engine.eval_str(template, data);
    println!(
        "   Standard engine: {:?}",
        standard_result.err().map(|e| e.to_string())
    );

    let templating_result = templating_engine.eval_str(template, data).unwrap();
    println!("   Templating engine: {}", templating_result);

    println!("\nDone!");
}