//! HoloLake numbered IPC root.
//!
//! Stable numbers are coordinates, not authority. Every operation first receives a
//! short-lived server-issued grant bound to the exact caller/channel/module/operation/
//! target tuple, protocol version, nonce and canonical payload digest. The grant is
//! consumed once before the internal handler runs. No business handler is registered
//! directly with Tauri.

use base64::Engine;
use ring::{digest, hmac, rand as ring_rand};
use ring_rand::SecureRandom;
use rusqlite::{params, Connection, OptionalExtension};
use serde::{Deserialize, Serialize};
use serde_json::{Map, Value};
use std::collections::{HashMap, HashSet};
use std::fs;
use std::path::PathBuf;
use std::sync::Mutex;
use std::time::{SystemTime, UNIX_EPOCH};
use tauri::{AppHandle, Manager, State};
use uuid::Uuid;

const EMBEDDED_REGISTRY: &str = include_str!("../../contracts/numbered-ipc-registry.json");
const EXPECTED_SCHEMA: &str = "hololake.numbered-ipc-registry/v1";
const EXPECTED_RECORD_ID: &str = "HLP-NUMBERED-IPC-ROOT-001";

#[derive(Clone, Debug, Deserialize)]
struct NumberedIpcRegistry {
    schema: String,
    record_id: String,
    runtime: RuntimeRules,
    payload_contract: PayloadContract,
    operations: Vec<OperationRoute>,
}

#[derive(Clone, Debug, Deserialize)]
struct RuntimeRules {
    public_tauri_command: String,
    caller_number: String,
    caller_number_subject_kind: String,
    caller_number_grants_persona_binding: bool,
    protocol_version: String,
    legacy_direct_commands_allowed: bool,
    grants_issued_server_side: bool,
    grant_single_use: bool,
    payload_bound_grants: bool,
    authority_binding_issued_server_side: bool,
    verified_human_binding_required_for_protected_routes: bool,
    persona_binding_claimed: bool,
    user_channel_body_binding_stage: String,
    maximum_grant_ttl_ms: u64,
    unknown_route: String,
    mismatched_coordinate: String,
    expired_or_replayed_grant: String,
    receipt_required: bool,
}

#[derive(Clone, Debug, Deserialize)]
struct PayloadContract {
    unknown_or_unclassified_alias: String,
    unknown_top_level_field: String,
    empty_object_aliases: Vec<String>,
    input_wrapper_aliases: Vec<String>,
    direct_field_aliases: HashMap<String, Vec<String>>,
}

#[derive(Clone, Debug, Deserialize)]
struct OperationRoute {
    operation_number: String,
    alias: String,
    handler: String,
    channel_number: String,
    module_number: String,
    target_number: String,
    admission: String,
    effect: String,
    payload_schema: String,
}

#[derive(Clone, Debug, Deserialize, Serialize, PartialEq, Eq)]
#[serde(rename_all = "camelCase")]
struct NumberedCoordinate {
    protocol_version: String,
    caller_number: String,
    channel_number: String,
    module_number: String,
    operation_number: String,
    target_number: String,
    request_nonce: String,
}

#[derive(Clone, Debug, Deserialize)]
#[serde(rename_all = "camelCase", deny_unknown_fields)]
struct NumberedEnvelope {
    #[serde(flatten)]
    coordinate: NumberedCoordinate,
    #[serde(default = "default_ttl_ms")]
    requested_ttl_ms: u64,
    #[serde(default)]
    payload: Value,
}

#[derive(Clone, Debug, Deserialize)]
#[serde(rename_all = "SCREAMING_SNAKE_CASE")]
enum NumberedIpcAction {
    IssueGrant,
    Execute,
}

#[derive(Clone, Debug, Deserialize)]
#[serde(rename_all = "camelCase", deny_unknown_fields)]
struct NumberedIpcInput {
    action: NumberedIpcAction,
    envelope: NumberedEnvelope,
    grant: Option<NumberedGrant>,
}

#[derive(Clone, Debug, Deserialize, Serialize)]
#[serde(rename_all = "camelCase")]
pub struct NumberedGrant {
    grant_id: String,
    expires_at_unix_ms: u64,
    payload_sha256: String,
    authority_binding_sha256: String,
    signature: String,
}

#[derive(Clone, Debug)]
struct GrantRecord {
    coordinate: NumberedCoordinate,
    expires_at_unix_ms: u64,
    payload_sha256: String,
    authority_binding_sha256: String,
    signature: String,
}

#[derive(Clone, Debug, Serialize)]
#[serde(rename_all = "camelCase")]
pub struct NumberedIpcReceipt {
    receipt_id: String,
    state: String,
    decision: String,
    operation_number: String,
    payload_sha256: String,
    authority_binding_sha256: String,
    observed_at_unix_ms: u64,
    previous_receipt_hash: String,
    receipt_hash: String,
    error: Option<String>,
}

#[derive(Clone, Debug, Serialize)]
#[serde(rename_all = "camelCase")]
pub struct NumberedIpcResponse {
    schema: &'static str,
    decision: String,
    grant: Option<NumberedGrant>,
    result: Option<Value>,
    error: Option<String>,
    receipt: NumberedIpcReceipt,
}

pub struct NumberedIpcState {
    signing_key: hmac::Key,
    grants: Mutex<HashMap<String, GrantRecord>>,
    ledger: Mutex<()>,
}

impl Default for NumberedIpcState {
    fn default() -> Self {
        let random = ring_rand::SystemRandom::new();
        let mut secret = [0_u8; 32];
        random
            .fill(&mut secret)
            .expect("operating system randomness is required for numbered IPC");
        Self {
            signing_key: hmac::Key::new(hmac::HMAC_SHA256, &secret),
            grants: Mutex::new(HashMap::new()),
            ledger: Mutex::new(()),
        }
    }
}

fn default_ttl_ms() -> u64 {
    10_000
}

fn now_unix_ms() -> u64 {
    SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .map(|duration| duration.as_millis() as u64)
        .unwrap_or(0)
}

fn sha256_hex(bytes: &[u8]) -> String {
    digest::digest(&digest::SHA256, bytes)
        .as_ref()
        .iter()
        .map(|byte| format!("{byte:02x}"))
        .collect()
}

fn canonical_value(value: &Value) -> Value {
    match value {
        Value::Array(values) => Value::Array(values.iter().map(canonical_value).collect()),
        Value::Object(object) => {
            let mut keys = object.keys().collect::<Vec<_>>();
            keys.sort();
            let mut canonical = Map::new();
            for key in keys {
                canonical.insert(key.clone(), canonical_value(&object[key]));
            }
            Value::Object(canonical)
        }
        _ => value.clone(),
    }
}

fn payload_digest(payload: &Value) -> Result<String, String> {
    let bytes = serde_json::to_vec(&canonical_value(payload))
        .map_err(|error| format!("HOLOLAKE_NUMBERED_IPC_PAYLOAD_INVALID: {error}"))?;
    if bytes.len() > 1_048_576 {
        return Err("HOLOLAKE_NUMBERED_IPC_PAYLOAD_TOO_LARGE".into());
    }
    Ok(sha256_hex(&bytes))
}

fn grant_signing_bytes(
    grant_id: &str,
    coordinate: &NumberedCoordinate,
    expires_at_unix_ms: u64,
    payload_sha256: &str,
    authority_binding_sha256: &str,
) -> Vec<u8> {
    format!(
        "HLP-NIPC-GRANT-v1\n{grant_id}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{}\n{expires_at_unix_ms}\n{payload_sha256}\n{authority_binding_sha256}",
        coordinate.protocol_version,
        coordinate.caller_number,
        coordinate.channel_number,
        coordinate.module_number,
        coordinate.operation_number,
        coordinate.target_number,
        coordinate.request_nonce,
        EXPECTED_RECORD_ID,
    )
    .into_bytes()
}

fn load_registry() -> Result<NumberedIpcRegistry, String> {
    let registry: NumberedIpcRegistry = serde_json::from_str(EMBEDDED_REGISTRY)
        .map_err(|error| format!("HOLOLAKE_NUMBERED_IPC_REGISTRY_INVALID: {error}"))?;
    validate_registry(&registry)?;
    Ok(registry)
}

fn validate_registry(registry: &NumberedIpcRegistry) -> Result<(), String> {
    let runtime = &registry.runtime;
    if registry.schema != EXPECTED_SCHEMA
        || registry.record_id != EXPECTED_RECORD_ID
        || runtime.public_tauri_command != "numbered_ipc"
        || runtime.caller_number_subject_kind != "PHYSICAL_WEBVIEW_ENTRY_NOT_PERSONA_IDENTITY"
        || runtime.caller_number_grants_persona_binding
        || runtime.legacy_direct_commands_allowed
        || !runtime.grants_issued_server_side
        || !runtime.grant_single_use
        || !runtime.payload_bound_grants
        || !runtime.authority_binding_issued_server_side
        || !runtime.verified_human_binding_required_for_protected_routes
        || runtime.persona_binding_claimed
        || runtime.user_channel_body_binding_stage != "SEPARATE_EVIDENCE_LAYER_NOT_YET_CLAIMED"
        || !runtime.receipt_required
        || runtime.maximum_grant_ttl_ms == 0
        || runtime.maximum_grant_ttl_ms > 30_000
        || runtime.unknown_route != "FAIL_CLOSED"
        || runtime.mismatched_coordinate != "FAIL_CLOSED"
        || runtime.expired_or_replayed_grant != "FAIL_CLOSED"
        || registry.operations.len() < 60
    {
        return Err("HOLOLAKE_NUMBERED_IPC_REGISTRY_BOUNDARY_INVALID".into());
    }
    if registry.payload_contract.unknown_or_unclassified_alias != "FAIL_CLOSED_BEFORE_GRANT"
        || registry.payload_contract.unknown_top_level_field != "FAIL_CLOSED_BEFORE_GRANT"
    {
        return Err("HOLOLAKE_NUMBERED_IPC_PAYLOAD_CONTRACT_INVALID".into());
    }
    let mut operation_numbers = HashSet::new();
    let mut aliases = HashSet::new();
    let mut coordinates = HashSet::new();
    for route in &registry.operations {
        let coordinate = format!(
            "{}/{}/{}/{}",
            route.channel_number, route.module_number, route.operation_number, route.target_number
        );
        if !operation_numbers.insert(route.operation_number.as_str())
            || !aliases.insert(route.alias.as_str())
            || !coordinates.insert(coordinate)
            || !route.operation_number.starts_with("HLP-NIPC-OP-")
            || !route.module_number.starts_with("HLP-NIPC-MOD-")
            || !route.channel_number.starts_with("HLP-NIPC-CH-")
            || !route.target_number.starts_with("HLP-NIPC-TGT-")
            || !route.handler.contains("::")
            || !matches!(
                route.admission.as_str(),
                "PREAUTH_SYSTEM_ROUTE" | "VERIFIED_HUMAN_ROUTE"
            )
            || !matches!(route.effect.as_str(), "READ_OR_STATUS" | "STATE_CHANGE")
            || !route
                .payload_schema
                .starts_with("hololake.numbered-ipc.payload/")
        {
            return Err("HOLOLAKE_NUMBERED_IPC_ROUTE_INVALID".into());
        }
    }
    let mut payload_aliases = HashSet::new();
    for alias in registry
        .payload_contract
        .empty_object_aliases
        .iter()
        .chain(registry.payload_contract.input_wrapper_aliases.iter())
        .chain(registry.payload_contract.direct_field_aliases.keys())
    {
        if !payload_aliases.insert(alias.as_str()) {
            return Err("HOLOLAKE_NUMBERED_IPC_PAYLOAD_ALIAS_DUPLICATED".into());
        }
    }
    if payload_aliases != aliases {
        return Err("HOLOLAKE_NUMBERED_IPC_PAYLOAD_COVERAGE_INCOMPLETE".into());
    }
    Ok(())
}

fn validate_payload_shape(
    registry: &NumberedIpcRegistry,
    route: &OperationRoute,
    payload: &Value,
) -> Result<(), String> {
    let object = payload
        .as_object()
        .ok_or_else(|| "HOLOLAKE_NUMBERED_IPC_PAYLOAD_OBJECT_REQUIRED".to_string())?;
    if registry
        .payload_contract
        .empty_object_aliases
        .iter()
        .any(|alias| alias == &route.alias)
    {
        return if object.is_empty() {
            Ok(())
        } else {
            Err("HOLOLAKE_NUMBERED_IPC_PAYLOAD_FIELD_UNKNOWN".into())
        };
    }
    if registry
        .payload_contract
        .input_wrapper_aliases
        .iter()
        .any(|alias| alias == &route.alias)
    {
        return if object.len() == 1 && object.contains_key("input") {
            Ok(())
        } else {
            Err("HOLOLAKE_NUMBERED_IPC_INPUT_WRAPPER_REQUIRED".into())
        };
    }
    if let Some(required_fields) = registry
        .payload_contract
        .direct_field_aliases
        .get(&route.alias)
    {
        let required = required_fields
            .iter()
            .map(String::as_str)
            .collect::<HashSet<_>>();
        let observed = object.keys().map(String::as_str).collect::<HashSet<_>>();
        if observed != required
            || required_fields
                .iter()
                .any(|field| !object.get(field).is_some_and(Value::is_string))
        {
            return Err("HOLOLAKE_NUMBERED_IPC_DIRECT_FIELDS_INVALID".into());
        }
        return Ok(());
    }
    Err("HOLOLAKE_NUMBERED_IPC_PAYLOAD_ALIAS_UNCLASSIFIED".into())
}

fn resolve_route<'a>(
    registry: &'a NumberedIpcRegistry,
    coordinate: &NumberedCoordinate,
) -> Result<&'a OperationRoute, String> {
    if coordinate.protocol_version != registry.runtime.protocol_version
        || coordinate.caller_number != registry.runtime.caller_number
    {
        return Err("HOLOLAKE_NUMBERED_IPC_CALLER_OR_PROTOCOL_MISMATCH".into());
    }
    if coordinate.request_nonce.len() < 16
        || coordinate.request_nonce.len() > 128
        || coordinate
            .request_nonce
            .chars()
            .any(|character| character.is_whitespace() || character.is_control())
    {
        return Err("HOLOLAKE_NUMBERED_IPC_NONCE_INVALID".into());
    }
    let route = registry
        .operations
        .iter()
        .find(|route| route.operation_number == coordinate.operation_number)
        .ok_or_else(|| "HOLOLAKE_NUMBERED_IPC_ROUTE_UNKNOWN".to_string())?;
    if route.channel_number != coordinate.channel_number
        || route.module_number != coordinate.module_number
        || route.target_number != coordinate.target_number
    {
        return Err("HOLOLAKE_NUMBERED_IPC_ROUTE_COORDINATE_MISMATCH".into());
    }
    Ok(route)
}

fn enforce_admission(app: &AppHandle, route: &OperationRoute) -> Result<String, String> {
    if route.admission == "PREAUTH_SYSTEM_ROUTE" {
        return Ok("SYSTEM_PHYSICAL_ENTRY:HLP-NIPC-CALLER-MAIN-WEBVIEW-0001".into());
    }
    let state = app.state::<crate::zero_point::ZeroPointState>();
    match crate::zero_point::verified_user_route(&state)? {
        Some((human_number, registry_domain)) => {
            Ok(format!("VERIFIED_HUMAN:{registry_domain}:{human_number}"))
        }
        None => Err("HOLOLAKE_NUMBERED_IPC_VERIFIED_HUMAN_REQUIRED".into()),
    }
}

fn issue_grant_at(
    state: &NumberedIpcState,
    registry: &NumberedIpcRegistry,
    envelope: &NumberedEnvelope,
    authority_binding: &str,
    now: u64,
) -> Result<(NumberedGrant, String), String> {
    let route = resolve_route(registry, &envelope.coordinate)?;
    validate_payload_shape(registry, route, &envelope.payload)?;
    if envelope.requested_ttl_ms == 0
        || envelope.requested_ttl_ms > registry.runtime.maximum_grant_ttl_ms
    {
        return Err("HOLOLAKE_NUMBERED_IPC_GRANT_TTL_INVALID".into());
    }
    let payload_sha256 = payload_digest(&envelope.payload)?;
    let authority_binding_sha256 = sha256_hex(authority_binding.as_bytes());
    let grant_id = format!("HLP-NIPC-GRANT-{}", Uuid::new_v4().simple());
    let expires_at_unix_ms = now.saturating_add(envelope.requested_ttl_ms);
    let signature = base64::engine::general_purpose::URL_SAFE_NO_PAD.encode(hmac::sign(
        &state.signing_key,
        &grant_signing_bytes(
            &grant_id,
            &envelope.coordinate,
            expires_at_unix_ms,
            &payload_sha256,
            &authority_binding_sha256,
        ),
    ));
    let record = GrantRecord {
        coordinate: envelope.coordinate.clone(),
        expires_at_unix_ms,
        payload_sha256: payload_sha256.clone(),
        authority_binding_sha256: authority_binding_sha256.clone(),
        signature: signature.clone(),
    };
    let mut grants = state
        .grants
        .lock()
        .map_err(|_| "HOLOLAKE_NUMBERED_IPC_GRANT_LOCK_POISONED".to_string())?;
    grants.retain(|_, existing| existing.expires_at_unix_ms >= now);
    grants.insert(grant_id.clone(), record);
    Ok((
        NumberedGrant {
            grant_id,
            expires_at_unix_ms,
            payload_sha256: payload_sha256.clone(),
            authority_binding_sha256,
            signature,
        },
        payload_sha256,
    ))
}

fn consume_grant_at(
    state: &NumberedIpcState,
    registry: &NumberedIpcRegistry,
    envelope: &NumberedEnvelope,
    grant: &NumberedGrant,
    authority_binding: &str,
    now: u64,
) -> Result<String, String> {
    let route = resolve_route(registry, &envelope.coordinate)?;
    validate_payload_shape(registry, route, &envelope.payload)?;
    let payload_sha256 = payload_digest(&envelope.payload)?;
    let authority_binding_sha256 = sha256_hex(authority_binding.as_bytes());
    let record = state
        .grants
        .lock()
        .map_err(|_| "HOLOLAKE_NUMBERED_IPC_GRANT_LOCK_POISONED".to_string())?
        .remove(&grant.grant_id)
        .ok_or_else(|| "HOLOLAKE_NUMBERED_IPC_GRANT_UNKNOWN_OR_REPLAYED".to_string())?;
    if now > record.expires_at_unix_ms
        || grant.expires_at_unix_ms != record.expires_at_unix_ms
        || grant.payload_sha256 != record.payload_sha256
        || payload_sha256 != record.payload_sha256
        || grant.authority_binding_sha256 != record.authority_binding_sha256
        || authority_binding_sha256 != record.authority_binding_sha256
        || grant.signature != record.signature
        || envelope.coordinate != record.coordinate
    {
        return Err("HOLOLAKE_NUMBERED_IPC_GRANT_MISMATCH_OR_EXPIRED".into());
    }
    let signature = base64::engine::general_purpose::URL_SAFE_NO_PAD
        .decode(&grant.signature)
        .map_err(|_| "HOLOLAKE_NUMBERED_IPC_GRANT_SIGNATURE_INVALID".to_string())?;
    hmac::verify(
        &state.signing_key,
        &grant_signing_bytes(
            &grant.grant_id,
            &envelope.coordinate,
            grant.expires_at_unix_ms,
            &grant.payload_sha256,
            &grant.authority_binding_sha256,
        ),
        &signature,
    )
    .map_err(|_| "HOLOLAKE_NUMBERED_IPC_GRANT_SIGNATURE_INVALID".to_string())?;
    Ok(payload_sha256)
}

fn ledger_path(app: &AppHandle) -> Result<PathBuf, String> {
    let root = app
        .path()
        .app_data_dir()
        .map_err(|error| format!("HOLOLAKE_NUMBERED_IPC_HOME_FAILED: {error}"))?
        .join("numbered-ipc-v1");
    fs::create_dir_all(&root)
        .map_err(|error| format!("HOLOLAKE_NUMBERED_IPC_HOME_CREATE_FAILED: {error}"))?;
    Ok(root.join("receipts.sqlite3"))
}

fn open_ledger(app: &AppHandle) -> Result<Connection, String> {
    let connection = Connection::open(ledger_path(app)?)
        .map_err(|error| format!("HOLOLAKE_NUMBERED_IPC_LEDGER_OPEN_FAILED: {error}"))?;
    connection
        .execute_batch(
            "PRAGMA journal_mode=WAL;
             PRAGMA busy_timeout=5000;
             CREATE TABLE IF NOT EXISTS receipts(
               sequence INTEGER PRIMARY KEY AUTOINCREMENT,
               receipt_id TEXT NOT NULL UNIQUE,
               state TEXT NOT NULL,
               decision TEXT NOT NULL,
               operation_number TEXT NOT NULL,
               payload_sha256 TEXT NOT NULL,
               authority_binding_sha256 TEXT NOT NULL DEFAULT '',
               observed_at_unix_ms INTEGER NOT NULL,
               previous_receipt_hash TEXT NOT NULL,
               receipt_hash TEXT NOT NULL UNIQUE,
               error TEXT
             );",
        )
        .map_err(|error| format!("HOLOLAKE_NUMBERED_IPC_LEDGER_SCHEMA_FAILED: {error}"))?;
    let has_authority_binding = {
        let mut statement = connection
            .prepare("PRAGMA table_info(receipts)")
            .map_err(|error| format!("HOLOLAKE_NUMBERED_IPC_LEDGER_SCHEMA_READ_FAILED: {error}"))?;
        let columns = statement
            .query_map([], |row| row.get::<_, String>(1))
            .map_err(|error| format!("HOLOLAKE_NUMBERED_IPC_LEDGER_SCHEMA_READ_FAILED: {error}"))?;
        let mut found = false;
        for column in columns {
            if column.map_err(|error| {
                format!("HOLOLAKE_NUMBERED_IPC_LEDGER_SCHEMA_READ_FAILED: {error}")
            })? == "authority_binding_sha256"
            {
                found = true;
            }
        }
        found
    };
    if !has_authority_binding {
        connection
            .execute(
                "ALTER TABLE receipts ADD COLUMN authority_binding_sha256 TEXT NOT NULL DEFAULT ''",
                [],
            )
            .map_err(|error| {
                format!("HOLOLAKE_NUMBERED_IPC_LEDGER_SCHEMA_MIGRATION_FAILED: {error}")
            })?;
    }
    Ok(connection)
}

#[allow(clippy::too_many_arguments)]
fn append_receipt(
    app: &AppHandle,
    state: &NumberedIpcState,
    event_state: &str,
    decision: &str,
    operation_number: &str,
    payload_sha256: &str,
    authority_binding_sha256: &str,
    error: Option<String>,
    now: u64,
) -> Result<NumberedIpcReceipt, String> {
    let _guard = state
        .ledger
        .lock()
        .map_err(|_| "HOLOLAKE_NUMBERED_IPC_LEDGER_LOCK_POISONED".to_string())?;
    let connection = open_ledger(app)?;
    let previous_receipt_hash = connection
        .query_row(
            "SELECT receipt_hash FROM receipts ORDER BY sequence DESC LIMIT 1",
            [],
            |row| row.get::<_, String>(0),
        )
        .optional()
        .map_err(|error| format!("HOLOLAKE_NUMBERED_IPC_LEDGER_READ_FAILED: {error}"))?
        .unwrap_or_else(|| "0".repeat(64));
    let receipt_id = format!("HLP-NIPC-RECEIPT-{}", Uuid::new_v4().simple());
    let receipt_hash = sha256_hex(
        format!(
            "HLP-NIPC-RECEIPT-v1\n{previous_receipt_hash}\n{receipt_id}\n{event_state}\n{decision}\n{operation_number}\n{payload_sha256}\n{authority_binding_sha256}\n{now}\n{}",
            error.as_deref().unwrap_or("")
        )
        .as_bytes(),
    );
    connection
        .execute(
            "INSERT INTO receipts(receipt_id,state,decision,operation_number,payload_sha256,
             authority_binding_sha256,observed_at_unix_ms,previous_receipt_hash,receipt_hash,error)
             VALUES(?1,?2,?3,?4,?5,?6,?7,?8,?9,?10)",
            params![
                receipt_id,
                event_state,
                decision,
                operation_number,
                payload_sha256,
                authority_binding_sha256,
                now,
                previous_receipt_hash,
                receipt_hash,
                error,
            ],
        )
        .map_err(|error| format!("HOLOLAKE_NUMBERED_IPC_LEDGER_APPEND_FAILED: {error}"))?;
    Ok(NumberedIpcReceipt {
        receipt_id,
        state: event_state.into(),
        decision: decision.into(),
        operation_number: operation_number.into(),
        payload_sha256: payload_sha256.into(),
        authority_binding_sha256: authority_binding_sha256.into(),
        observed_at_unix_ms: now,
        previous_receipt_hash,
        receipt_hash,
        error,
    })
}

#[allow(clippy::too_many_arguments)]
fn response(
    app: &AppHandle,
    state: &NumberedIpcState,
    event_state: &str,
    decision: &str,
    operation_number: &str,
    payload_sha256: &str,
    grant: Option<NumberedGrant>,
    result: Option<Value>,
    error: Option<String>,
    now: u64,
) -> Result<NumberedIpcResponse, String> {
    let receipt = append_receipt(
        app,
        state,
        event_state,
        decision,
        operation_number,
        payload_sha256,
        &sha256_hex(b"UNBOUND_AUTHORITY"),
        error.clone(),
        now,
    )?;
    Ok(NumberedIpcResponse {
        schema: "hololake.numbered-ipc-response/v1",
        decision: decision.into(),
        grant,
        result,
        error,
        receipt,
    })
}

#[allow(clippy::too_many_arguments)]
fn bound_response(
    app: &AppHandle,
    state: &NumberedIpcState,
    authority_binding: &str,
    event_state: &str,
    decision: &str,
    operation_number: &str,
    payload_sha256: &str,
    grant: Option<NumberedGrant>,
    result: Option<Value>,
    error: Option<String>,
    now: u64,
) -> Result<NumberedIpcResponse, String> {
    let receipt = append_receipt(
        app,
        state,
        event_state,
        decision,
        operation_number,
        payload_sha256,
        &sha256_hex(authority_binding.as_bytes()),
        error.clone(),
        now,
    )?;
    Ok(NumberedIpcResponse {
        schema: "hololake.numbered-ipc-response/v1",
        decision: decision.into(),
        grant,
        result,
        error,
        receipt,
    })
}

pub(crate) fn start_on_application_open(app: &AppHandle) -> Result<(), String> {
    let _ = load_registry()?;
    let _ = open_ledger(app)?;
    Ok(())
}

#[tauri::command]
pub async fn numbered_ipc(
    app: AppHandle,
    state: State<'_, NumberedIpcState>,
    input: Value,
) -> Result<NumberedIpcResponse, String> {
    let now = now_unix_ms();
    let request: NumberedIpcInput = serde_json::from_value(input)
        .map_err(|error| format!("HOLOLAKE_NUMBERED_IPC_ENVELOPE_INVALID: {error}"))?;
    let registry = load_registry()?;
    let operation_number = request.envelope.coordinate.operation_number.clone();
    let digest = payload_digest(&request.envelope.payload).unwrap_or_default();
    let route = match resolve_route(&registry, &request.envelope.coordinate) {
        Ok(route) => route,
        Err(error) => {
            return response(
                &app,
                &state,
                "ROUTE_REJECTED",
                "DENY",
                &operation_number,
                &digest,
                None,
                None,
                Some(error),
                now,
            )
        }
    };
    let authority_binding = match enforce_admission(&app, route) {
        Ok(binding) => binding,
        Err(error) => {
            return response(
                &app,
                &state,
                "ADMISSION_REJECTED",
                "DENY",
                &operation_number,
                &digest,
                None,
                None,
                Some(error),
                now,
            )
        }
    };
    match request.action {
        NumberedIpcAction::IssueGrant => {
            if request.grant.is_some() {
                return bound_response(
                    &app,
                    &state,
                    &authority_binding,
                    "GRANT_REJECTED",
                    "DENY",
                    &operation_number,
                    &digest,
                    None,
                    None,
                    Some("HOLOLAKE_NUMBERED_IPC_UNEXPECTED_GRANT".into()),
                    now,
                );
            }
            match issue_grant_at(
                &state,
                &registry,
                &request.envelope,
                &authority_binding,
                now,
            ) {
                Ok((grant, payload_sha256)) => bound_response(
                    &app,
                    &state,
                    &authority_binding,
                    "GRANT_ISSUED",
                    "ALLOW",
                    &operation_number,
                    &payload_sha256,
                    Some(grant),
                    None,
                    None,
                    now,
                ),
                Err(error) => bound_response(
                    &app,
                    &state,
                    &authority_binding,
                    "GRANT_REJECTED",
                    "DENY",
                    &operation_number,
                    &digest,
                    None,
                    None,
                    Some(error),
                    now,
                ),
            }
        }
        NumberedIpcAction::Execute => {
            let Some(grant) = request.grant.as_ref() else {
                return bound_response(
                    &app,
                    &state,
                    &authority_binding,
                    "EXECUTION_REJECTED",
                    "DENY",
                    &operation_number,
                    &digest,
                    None,
                    None,
                    Some("HOLOLAKE_NUMBERED_IPC_GRANT_REQUIRED".into()),
                    now,
                );
            };
            let payload_sha256 = match consume_grant_at(
                &state,
                &registry,
                &request.envelope,
                grant,
                &authority_binding,
                now,
            ) {
                Ok(payload_sha256) => payload_sha256,
                Err(error) => {
                    return bound_response(
                        &app,
                        &state,
                        &authority_binding,
                        "EXECUTION_REJECTED",
                        "DENY",
                        &operation_number,
                        &digest,
                        None,
                        None,
                        Some(error),
                        now,
                    )
                }
            };
            match crate::numbered_ipc_dispatch::dispatch(
                app.clone(),
                &route.handler,
                request.envelope.payload,
            )
            .await
            {
                Ok(result) => bound_response(
                    &app,
                    &state,
                    &authority_binding,
                    "EXECUTED",
                    "ALLOW",
                    &operation_number,
                    &payload_sha256,
                    None,
                    Some(result),
                    None,
                    now_unix_ms(),
                ),
                Err(error) => bound_response(
                    &app,
                    &state,
                    &authority_binding,
                    "HANDLER_REJECTED",
                    "DENY",
                    &operation_number,
                    &payload_sha256,
                    None,
                    None,
                    Some(error),
                    now_unix_ms(),
                ),
            }
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    fn envelope_for(route: &OperationRoute, payload: Value) -> NumberedEnvelope {
        NumberedEnvelope {
            coordinate: NumberedCoordinate {
                protocol_version: "HLP-NIPC-v1".into(),
                caller_number: "HLP-NIPC-CALLER-MAIN-WEBVIEW-0001".into(),
                channel_number: route.channel_number.clone(),
                module_number: route.module_number.clone(),
                operation_number: route.operation_number.clone(),
                target_number: route.target_number.clone(),
                request_nonce: format!("test-{}", Uuid::new_v4().simple()),
            },
            requested_ttl_ms: 1_000,
            payload,
        }
    }

    #[test]
    fn registry_is_closed_and_contains_every_migrated_command() {
        let registry = load_registry().unwrap();
        assert_eq!(registry.operations.len(), 147);
        assert!(!registry.runtime.legacy_direct_commands_allowed);
    }

    #[test]
    fn route_coordinates_cannot_be_mixed() {
        let registry = load_registry().unwrap();
        let mut envelope = envelope_for(&registry.operations[0], Value::Null);
        envelope.coordinate.target_number = registry.operations[1].target_number.clone();
        assert_eq!(
            resolve_route(&registry, &envelope.coordinate).unwrap_err(),
            "HOLOLAKE_NUMBERED_IPC_ROUTE_COORDINATE_MISMATCH"
        );
    }

    #[test]
    fn grant_is_payload_bound_single_use_and_expires() {
        let registry = load_registry().unwrap();
        let state = NumberedIpcState::default();
        let route = registry
            .operations
            .iter()
            .find(|route| route.alias == "confirm_hololake_update_install")
            .unwrap();
        let envelope = envelope_for(route, serde_json::json!({"input": {"a": 1}}));
        let authority = "VERIFIED_HUMAN:ICE_GL:test-user";
        let (grant, _) = issue_grant_at(&state, &registry, &envelope, authority, 100).unwrap();
        assert!(consume_grant_at(&state, &registry, &envelope, &grant, authority, 101).is_ok());
        assert_eq!(
            consume_grant_at(&state, &registry, &envelope, &grant, authority, 102).unwrap_err(),
            "HOLOLAKE_NUMBERED_IPC_GRANT_UNKNOWN_OR_REPLAYED"
        );

        let (expired, _) = issue_grant_at(&state, &registry, &envelope, authority, 200).unwrap();
        assert_eq!(
            consume_grant_at(&state, &registry, &envelope, &expired, authority, 1_201,)
                .unwrap_err(),
            "HOLOLAKE_NUMBERED_IPC_GRANT_MISMATCH_OR_EXPIRED"
        );

        let changed = envelope_for(route, serde_json::json!({"input": {"a": 2}}));
        let (bound, _) = issue_grant_at(&state, &registry, &changed, authority, 300).unwrap();
        let mut tampered = changed.clone();
        tampered.payload = serde_json::json!({"input": {"a": 3}});
        assert_eq!(
            consume_grant_at(&state, &registry, &tampered, &bound, authority, 301).unwrap_err(),
            "HOLOLAKE_NUMBERED_IPC_GRANT_MISMATCH_OR_EXPIRED"
        );

        let (rebound, _) = issue_grant_at(&state, &registry, &envelope, authority, 400).unwrap();
        assert_eq!(
            consume_grant_at(
                &state,
                &registry,
                &envelope,
                &rebound,
                "VERIFIED_HUMAN:TCS_GL:other-user",
                401,
            )
            .unwrap_err(),
            "HOLOLAKE_NUMBERED_IPC_GRANT_MISMATCH_OR_EXPIRED"
        );
    }

    #[test]
    fn payload_outer_shape_is_closed_before_a_grant_is_issued() {
        let registry = load_registry().unwrap();
        let empty_route = registry
            .operations
            .iter()
            .find(|route| route.alias == "get_hololake_home_status")
            .unwrap();
        assert!(validate_payload_shape(&registry, empty_route, &serde_json::json!({})).is_ok());
        assert_eq!(
            validate_payload_shape(
                &registry,
                empty_route,
                &serde_json::json!({"unexpected": true}),
            )
            .unwrap_err(),
            "HOLOLAKE_NUMBERED_IPC_PAYLOAD_FIELD_UNKNOWN"
        );

        let direct_route = registry
            .operations
            .iter()
            .find(|route| route.alias == "perform_code_repo_login")
            .unwrap();
        assert!(validate_payload_shape(
            &registry,
            direct_route,
            &serde_json::json!({"username": "u", "password": "p"}),
        )
        .is_ok());
        assert_eq!(
            validate_payload_shape(
                &registry,
                direct_route,
                &serde_json::json!({"username": "u", "password": "p", "role": "admin"}),
            )
            .unwrap_err(),
            "HOLOLAKE_NUMBERED_IPC_DIRECT_FIELDS_INVALID"
        );
    }
}