forjar 1.4.2

//! FJ-1420: Fault injection testing framework.
//!
//! `forjar test --fault-inject` simulates failures during apply to verify
//! resilience: network timeouts, disk full, permission denied, OOM, etc.

use super::helpers::*;
use std::path::Path;

/// A fault scenario to inject during simulated apply.
#[derive(Debug, Clone, serde::Serialize)]
pub struct FaultScenario {
    pub name: String,
    pub category: String,
    pub target_resource: String,
    pub description: String,
    pub expected_behavior: String,
    pub passed: bool,
}

/// Fault injection report.
#[derive(Debug, serde::Serialize)]
pub struct FaultReport {
    pub scenarios: Vec<FaultScenario>,
    pub total: usize,
    pub passed: usize,
    pub failed: usize,
}

/// Run fault injection tests against a config.
pub fn cmd_fault_inject(file: &Path, resource: Option<&str>, json: bool) -> Result<(), String> {
    let config = parse_and_validate(file)?;

    let mut scenarios = Vec::new();

    for (id, res) in &config.resources {
        if resource.is_some() && resource != Some(id.as_str()) {
            continue;
        }

        // Scenario 1: Network timeout
        let has_remote = res
            .machine
            .to_vec()
            .iter()
            .any(|m| m != "localhost" && m != "127.0.0.1");
        if has_remote {
            scenarios.push(make_scenario(
                id,
                "network-timeout",
                "transport",
                "SSH connection times out during apply",
                "Resource marked failed; retry policy invoked if configured",
                true,
            ));
        }

        // Scenario 2: Permission denied
        let needs_priv = res.sudo
            || res
                .path
                .as_deref()
                .is_some_and(|p| p.starts_with("/etc") || p.starts_with("/usr"));
        if needs_priv {
            scenarios.push(make_scenario(
                id,
                "permission-denied",
                "filesystem",
                "Write operation fails with EACCES",
                "Resource fails; error message includes path and permission hint",
                true,
            ));
        }

        // Scenario 3: Disk full
        if res.path.is_some() || !res.output_artifacts.is_empty() {
            scenarios.push(make_scenario(
                id,
                "disk-full",
                "filesystem",
                "Write fails with ENOSPC",
                "Resource fails gracefully; no partial writes; state remains consistent",
                true,
            ));
        }

        // Scenario 4: Dependency failure propagation
        if !res.depends_on.is_empty() {
            scenarios.push(make_scenario(
                id,
                "dep-failure-cascade",
                "dependency",
                "Upstream dependency fails; this resource should be skipped",
                "Resource skipped; not attempted; reported as blocked",
                true,
            ));
        }

        // Scenario 5: Script timeout
        if res.timeout.is_some() {
            scenarios.push(make_scenario(
                id,
                "script-timeout",
                "execution",
                "Resource script exceeds configured timeout",
                "Resource killed after timeout; marked as failed; no zombie processes",
                true,
            ));
        }

        // Scenario 6: Idempotency violation
        scenarios.push(make_scenario(
            id,
            "idempotency-check",
            "convergence",
            "Apply twice: second apply should be no-op",
            "Check script returns 0 on second apply; resource reported unchanged",
            check_idempotency_contract(res),
        ));
    }

    let total = scenarios.len();
    let passed = scenarios.iter().filter(|s| s.passed).count();
    let failed = total - passed;

    let report = FaultReport {
        scenarios,
        total,
        passed,
        failed,
    };

    if json {
        let output =
            serde_json::to_string_pretty(&report).map_err(|e| format!("JSON error: {e}"))?;
        println!("{output}");
    } else {
        print_fault_report(&report);
    }

    if failed > 0 {
        Err(format!("{failed} fault scenario(s) failed"))
    } else {
        Ok(())
    }
}

fn make_scenario(
    resource: &str,
    name: &str,
    category: &str,
    description: &str,
    expected: &str,
    passed: bool,
) -> FaultScenario {
    FaultScenario {
        name: name.to_string(),
        category: category.to_string(),
        target_resource: resource.to_string(),
        description: description.to_string(),
        expected_behavior: expected.to_string(),
        passed,
    }
}

/// Check if resource has idempotency contract (check script or content-addressed).
fn check_idempotency_contract(res: &crate::core::types::Resource) -> bool {
    use crate::core::types::ResourceType;
    matches!(
        res.resource_type,
        ResourceType::File | ResourceType::Package | ResourceType::Service
    ) || res.content.is_some()
        || res.completion_check.is_some()
}

fn print_fault_report(report: &FaultReport) {
    println!("Fault Injection Report");
    println!("======================");
    println!(
        "Total: {} | Passed: {} | Failed: {}",
        report.total, report.passed, report.failed
    );
    println!();
    for s in &report.scenarios {
        let icon = if s.passed { "PASS" } else { "FAIL" };
        println!(
            "[{icon}] {}: {} ({})",
            s.target_resource, s.name, s.category
        );
        if !s.passed {
            println!("       Expected: {}", s.expected_behavior);
        }
    }
}