//! The firmware-agnostic discovery facade.
//!
//! The kernel calls `platform.discover()` and gets back a generic `DeviceTree`
//! without ever naming ACPI or device-tree — the same way it imports `arch`
//! without naming x86_64. Which backend runs is decided *at runtime* from what
//! the bootloader handed us (an ACPI RSDP today, a device-tree blob later),
//! because a single image — a future ARM kernel especially — may boot under
//! either firmware. That's a deliberate divergence from `arch`, which is a
//! compile-time choice.

const std = @import("std");
const danos = @import("danos");
const device = @import("device.zig");
const acpi = @import("acpi.zig");
const power = @import("power.zig");
const devicetree = @import("devicetree.zig");

pub const DeviceTree = device.DeviceTree;
pub const Device = device.Device;
pub const DeviceClass = device.DeviceClass;
pub const Hal = device.Hal;
pub const PowerInfo = acpi.PowerInfo;
pub const AmlStats = acpi.AmlStats;
pub const PlatformInfo = acpi.PlatformInfo;
pub const RegAccess = acpi.RegAccess;
pub const IsoEntry = acpi.IsoEntry;

/// The register map + sleep types discovery extracted, for logging/diagnostics.
pub fn powerInfo() PowerInfo {
    return acpi.power_info;
}

/// The scalar firmware facts the arch layer needs to avoid legacy assumptions
/// (8259 presence, LAPIC base, PM timer, SPCR UART, IRQ overrides).
pub fn platformInfo() PlatformInfo {
    return acpi.platform_info;
}

/// AML parse integrity/diagnostics (namespace node count, bytes consumed).
pub fn amlStats() AmlStats {
    return acpi.aml_stats;
}

/// Enumerate hardware into a fresh device tree. `hal` supplies the hardware
/// primitives the backend needs (MMIO mapping for PCIe config space, port I/O for
/// ACPI registers); pass the arch implementation. Errors leave nothing to clean up
/// beyond the tree's own allocations.
pub fn discover(
    boot_info: *const danos.BootInfo,
    allocator: std.mem.Allocator,
    hal: Hal,
) !DeviceTree {
    var dt = try DeviceTree.init(allocator);

    if (boot_info.acpi_rsdp != 0) {
        try acpi.discover(boot_info.acpi_rsdp, &dt, hal);
    } else {
        // No ACPI RSDP. A device-tree boot would parse its blob here; today that
        // path is a stub, so this reports the machine described itself no way we
        // understand yet.
        try devicetree.discover(&dt);
    }

    return dt;
}

/// Restart the machine. Never returns on success; returns only if no reset method
/// worked (extremely unlikely). Backend-agnostic entry the kernel calls.
pub fn reboot(hal: Hal) void {
    power.reboot(hal);
}

/// Power the machine off (ACPI S5). Never returns on success.
pub fn shutdown(hal: Hal) void {
    power.shutdown(hal);
}