// config.reef — TOML service definition parser
//
// Parses /etc/zyginit.d/*.toml service definitions into ServiceDef structs.
// Uses Reef's built-in TOML parser: import encoding.toml
//
// This module should be implemented first — it has no illumos dependencies
// and can be tested on any platform.

import encoding.toml
import io.fs

// Service types
enum ServiceType {
    Daemon,     // long-running process, restarted on exit
    Oneshot,    // runs once, considered "started" after exit 0
    Transient,  // runs once, not tracked after exit
}

// Restart policy
enum RestartPolicy {
    Always,
    OnFailure,
    Never,
}

// Stop method
enum StopMethod {
    Contract,   // signal all processes in contract (default)
    Exec,       // run a stop command
}

// Service definition — parsed from TOML
struct ServiceDef {
    name: String,
    description: String,
    service_type: ServiceType,

    // exec
    start_cmd: String,
    stop_cmd: Option<String>,

    // stop
    stop_method: StopMethod,
    stop_signal: String,       // "TERM", "HUP", etc.
    stop_timeout: i32,         // seconds

    // dependencies
    requires: Vec<String>,     // hard dependencies — must be running
    after: Vec<String>,        // ordering — start after these, but don't require

    // contract
    contract_param: Vec<String>,
    contract_fatal: Vec<String>,

    // restart
    restart_policy: RestartPolicy,
    restart_delay: i32,        // seconds
    max_retries: i32,          // -1 = unlimited
}

// Parse a single TOML file into a ServiceDef
fn parse_service(path: String) -> Result<ServiceDef, String> {
    // TODO: implement
    // 1. Read file contents
    // 2. Parse TOML
    // 3. Extract fields with defaults
    // 4. Validate required fields
    Err("not yet implemented")
}

// Scan /etc/zyginit.d/enabled.d/ and return list of enabled service paths
fn scan_enabled(config_dir: String) -> Result<Vec<String>, String> {
    // TODO: implement
    // 1. Read symlinks in enabled.d/
    // 2. Resolve each to its .toml file
    // 3. Return list of absolute paths
    Err("not yet implemented")
}

// Load all enabled services
fn load_enabled_services(config_dir: String) -> Result<Vec<ServiceDef>, String> {
    // TODO: implement
    // 1. scan_enabled()
    // 2. parse_service() for each
    // 3. Return Vec of ServiceDefs
    Err("not yet implemented")
}
// contract.reef — illumos process contract FFI bindings
//
// Provides Reef wrappers around libcontract for managing service processes.
// Process contracts are an illumos kernel feature — this module ONLY works
// on illumos/Hammerhead.
//
// Reference: illumos libcontract(3LIB), contract(5), process(5)
// Source reference: hammerhead/usr/src/cmd/svc/startd/contract.c

// C FFI declarations for libcontract
extern "C" {
    // Template management
    fn ct_tmpl_activate(fd: i32) -> i32;
    fn ct_tmpl_clear(fd: i32) -> i32;
    fn ct_tmpl_set_informative(fd: i32, events: u32) -> i32;
    fn ct_tmpl_set_critical(fd: i32, events: u32) -> i32;

    // Process contract template
    fn ct_pr_tmpl_set_fatal(fd: i32, events: u32) -> i32;
    fn ct_pr_tmpl_set_param(fd: i32, params: u32) -> i32;

    // Contract status
    fn ct_status_read(fd: i32, detail: i32, statp: *mut CtStatus) -> i32;
    fn ct_status_free(status: *mut CtStatus);
    fn ct_status_get_id(status: *CtStatus) -> i32;

    // Contract control
    fn ct_ctl_abandon(fd: i32) -> i32;
    fn ct_ctl_adopt(fd: i32) -> i32;

    // POSIX
    fn open(path: *const u8, flags: i32) -> i32;
    fn close(fd: i32) -> i32;
    fn fork() -> i32;
    fn execvp(file: *const u8, argv: *const *const u8) -> i32;
    fn setsid() -> i32;
    fn sigsend(idtype: i32, id: i64, sig: i32) -> i32;
    fn poll(fds: *mut PollFd, nfds: i32, timeout: i32) -> i32;
}

// Contract event flags
const CT_PR_EV_EMPTY: u32 = 0x01;    // all processes exited
const CT_PR_EV_FORK: u32 = 0x02;     // process forked
const CT_PR_EV_EXIT: u32 = 0x04;     // process exited
const CT_PR_EV_CORE: u32 = 0x08;     // process dumped core
const CT_PR_EV_SIGNAL: u32 = 0x10;   // fatal signal
const CT_PR_EV_HWERR: u32 = 0x20;    // hardware error

// Contract parameter flags
const CT_PR_INHERIT: u32 = 0x01;     // inherit contract on fork
const CT_PR_NOORPHAN: u32 = 0x02;    // kill orphans on contract abandon

// Contract template path
const CTFS_PROCESS_TEMPLATE: &str = "/system/contract/process/template";
const CTFS_PROCESS_LATEST: &str = "/system/contract/process/latest";
const CTFS_PROCESS_BUNDLE: &str = "/system/contract/process/bundle";

// Managed contract handle
struct Contract {
    id: i32,           // contract ID from kernel
    service_name: String,
    bundle_fd: i32,    // fd for event monitoring
}

// Set up a contract template for forking a service
fn setup_template() -> Result<i32, String> {
    // TODO: implement
    // 1. open(CTFS_PROCESS_TEMPLATE, O_RDWR)
    // 2. ct_tmpl_set_informative(fd, CT_PR_EV_EMPTY)
    // 3. ct_tmpl_set_critical(fd, CT_PR_EV_EMPTY | CT_PR_EV_HWERR)
    // 4. ct_pr_tmpl_set_fatal(fd, CT_PR_EV_HWERR)
    // 5. ct_pr_tmpl_set_param(fd, CT_PR_INHERIT | CT_PR_NOORPHAN)
    // 6. ct_tmpl_activate(fd)
    // 7. Return fd
    Err("not yet implemented")
}

// After fork(), retrieve the contract ID for the new child
fn get_latest_contract() -> Result<i32, String> {
    // TODO: implement
    // 1. open(CTFS_PROCESS_LATEST, O_RDONLY)
    // 2. ct_status_read()
    // 3. ct_status_get_id()
    // 4. Return contract ID
    Err("not yet implemented")
}

// Open the contract bundle fd for poll()-based event monitoring
fn open_bundle() -> Result<i32, String> {
    // TODO: implement
    Err("not yet implemented")
}

// Kill all processes in a contract
fn kill_contract(contract_id: i32, signal: i32) -> Result<(), String> {
    // TODO: implement using sigsend(P_CTID, contract_id, signal)
    Err("not yet implemented")
}

// Re-adopt an existing contract (after zyginit restart)
fn adopt_contract(contract_id: i32) -> Result<(), String> {
    // TODO: implement
    Err("not yet implemented")
}
// depgraph.reef — Dependency graph and topological sort
//
// Builds a directed acyclic graph from ServiceDef dependencies,
// performs topological sort to determine boot order, and identifies
// services that can start in parallel.
//
// This module has no illumos dependencies — can be tested on any platform.

import config.{ServiceDef}

// A node in the dependency graph
struct DepNode {
    name: String,
    service: ServiceDef,
    edges: Vec<String>,     // services this depends on (requires + after)
    in_degree: i32,         // number of unsatisfied dependencies
}

// The full dependency graph
struct DepGraph {
    nodes: Map<String, DepNode>,
}

// Build a dependency graph from a list of service definitions
fn build_graph(services: Vec<ServiceDef>) -> Result<DepGraph, String> {
    // TODO: implement
    // 1. Create a DepNode for each service
    // 2. Add edges for requires + after dependencies
    // 3. Detect missing dependencies (warn, don't fail)
    // 4. Detect cycles (fail with clear error message)
    Err("not yet implemented")
}

// Topological sort — returns services grouped by startup tier
// Services within the same tier can start in parallel.
//
// Returns: Vec<Vec<String>> — each inner Vec is a parallel tier
// Example: [["root-fs"], ["filesystem", "loopback"], ["network", "syslog"], ["sshd", "cron"]]
fn topo_sort(graph: DepGraph) -> Result<Vec<Vec<String>>, String> {
    // TODO: implement using Kahn's algorithm
    // 1. Find all nodes with in_degree == 0 → first tier
    // 2. Remove those nodes, decrement in_degree of dependents
    // 3. Repeat until all nodes placed
    // 4. If nodes remain with in_degree > 0 → cycle detected
    Err("not yet implemented")
}

// Check for dependency cycles — returns the cycle path if found
fn detect_cycle(graph: DepGraph) -> Option<Vec<String>> {
    // TODO: implement using DFS with coloring
    None
}
// socket.reef — Unix domain socket server for zygctl communication
//
// Listens on /var/run/zyginit.sock for commands from zygctl.
// Protocol: newline-delimited text commands, JSON responses.
//
// Commands:
//   status              → list all services and their states
//   status <name>       → status of a single service
//   start <name>        → start a service (transient, not persisted)
//   stop <name>         → stop a service
//   restart <name>      → stop then start
//   enable <name>       → create symlink in enabled.d/ (persisted)
//   disable <name>      → remove symlink from enabled.d/
//   list                → list all known service definitions

const SOCKET_PATH: &str = "/var/run/zyginit.sock";

// Create and bind the Unix domain socket
fn create_socket() -> Result<i32, String> {
    // TODO: implement
    // 1. socket(AF_UNIX, SOCK_STREAM, 0)
    // 2. bind() to SOCKET_PATH
    // 3. listen()
    // 4. Return fd for poll()
    Err("not yet implemented")
}

// Handle a client connection — read command, dispatch, respond
fn handle_client(client_fd: i32) -> Result<(), String> {
    // TODO: implement
    // 1. Read command line from client
    // 2. Parse command + args
    // 3. Dispatch to appropriate handler
    // 4. Send response (JSON)
    // 5. Close client fd
    Err("not yet implemented")
}
// supervisor.reef — Service lifecycle management
//
// Handles starting, stopping, and restarting services using process
// contracts. Implements restart policies (always, on-failure, never).

import config.{ServiceDef, ServiceType, RestartPolicy, StopMethod}
import contract.{Contract, setup_template, get_latest_contract, kill_contract}

// Runtime state of a service
enum ServiceState {
    Disabled,       // not enabled
    Waiting,        // waiting for dependencies
    Starting,       // exec'd, waiting for confirmation
    Running,        // running (has contract)
    Stopping,       // stop signal sent, waiting for exit
    Stopped,        // cleanly stopped
    Failed,         // exited with error
    Maintenance,    // exceeded max retries
}

// Runtime info for a managed service
struct ServiceRuntime {
    def: ServiceDef,
    state: ServiceState,
    contract: Option<Contract>,
    pid: Option<i32>,
    restart_count: i32,
    last_exit_code: Option<i32>,
    last_start_time: i64,     // unix timestamp
}

// Start a service — fork, set up contract, exec
fn start_service(svc: ServiceDef) -> Result<ServiceRuntime, String> {
    // TODO: implement
    // 1. setup_template() for contract
    // 2. fork()
    // 3. In child: setsid(), exec(svc.start_cmd)
    // 4. In parent: get_latest_contract(), ct_tmpl_clear()
    // 5. Return ServiceRuntime with Running state
    Err("not yet implemented")
}

// Stop a service
fn stop_service(rt: ServiceRuntime) -> Result<ServiceRuntime, String> {
    // TODO: implement
    // Based on svc.stop_method:
    //   Contract: kill_contract(contract_id, signal)
    //   Exec: fork/exec the stop command
    // Wait up to stop_timeout, then SIGKILL
    Err("not yet implemented")
}

// Handle a contract event (service exited)
fn handle_exit(rt: ServiceRuntime, exit_code: i32) -> ServiceRuntime {
    // TODO: implement
    // Based on restart_policy:
    //   Always: schedule restart after delay
    //   OnFailure: restart only if exit_code != 0
    //   Never: mark as Stopped
    // Check max_retries — enter Maintenance if exceeded
    rt
}
// zygctl.reef — Administrative CLI for zyginit
//
// Communicates with the running zyginit daemon over Unix domain socket
// at /var/run/zyginit.sock.
//
// Usage:
//   zygctl status              # list all services
//   zygctl status <name>       # status of one service
//   zygctl start <name>        # start a service (transient)
//   zygctl stop <name>         # stop a service
//   zygctl restart <name>      # restart a service
//   zygctl enable <name>       # enable at boot (creates symlink)
//   zygctl disable <name>      # disable at boot (removes symlink)
//   zygctl list                # list all service definitions

const SOCKET_PATH: &str = "/var/run/zyginit.sock";

fn main() -> i32 {
    // TODO: implement
    // 1. Parse command-line arguments
    // 2. Connect to Unix domain socket
    // 3. Send command
    // 4. Read and display response
    // 5. For enable/disable: also manage symlinks in enabled.d/

    0
}
// zyginit.reef — Main init daemon (PID 1)
//
// This is the entry point for the Zygaena init system.
// It replaces SMF's svc.startd + svc.configd + master restarter.
//
// Boot sequence:
//   1. Scan /etc/zyginit.d/enabled.d/ for enabled services
//   2. Parse TOML definitions → ServiceDef structs
//   3. Build dependency graph → topological sort
//   4. Start services in parallel, respecting dependency order
//   5. Mount tmpfs, create /var/run/zyginit.sock
//   6. Enter poll(2) event loop

import config.{load_enabled_services, ServiceDef}
import depgraph.{build_graph, topo_sort}
import contract.{open_bundle}
import supervisor.{start_service, handle_exit, ServiceRuntime, ServiceState}
import socket.{create_socket, handle_client}

const CONFIG_DIR: &str = "/etc/zyginit.d";
const DIAG_DIR: &str = "/var/run/zyginit";

fn main() -> i32 {
    // TODO: implement

    // Phase 1: Load configuration
    // let services = load_enabled_services(CONFIG_DIR)?;

    // Phase 2: Build dependency graph and compute boot order
    // let graph = build_graph(services)?;
    // let tiers = topo_sort(graph)?;

    // Phase 3: Start services tier by tier
    // for tier in tiers {
    //     // Start all services in this tier in parallel
    //     for svc_name in tier {
    //         start_service(services[svc_name]);
    //     }
    //     // Wait for all services in tier to reach Running state
    // }

    // Phase 4: Set up communication
    // let bundle_fd = open_bundle()?;
    // let socket_fd = create_socket()?;
    // let signal_fd = setup_signal_pipe()?;  // self-pipe trick for signals

    // Phase 5: Event loop
    // loop {
    //     poll([bundle_fd, socket_fd, signal_fd], -1);
    //     // Handle contract events (service exits)
    //     // Handle socket connections (zygctl commands)
    //     // Handle signals (SIGCHLD, SIGTERM, SIGHUP for reload)
    // }

    0
}