//! PersonaService — the SoulStream identity, held by the bundled Freenet
//! identity delegate and reached only through the FreenetAdapter.
//!
//! The delegate wasm ships as an app asset (`assets/identity_delegate.wasm`,
//! sha256 84dd8dbb…, the generation every F1–F2b spike validated). Its key
//! namespace is (code hash, params), so THESE BYTES ARE A COMMITMENT:
//! changing them re-keys the delegate and strands every user's persona —
//! and the platform's copy-forward is disabled (GHSA-824h-7x5x-wfmf), so
//! the only migration is export-artifact → new generation → import,
//! verified by reading the identity back (F1's record). Treat any change
//! as a migration event, never a routine rebuild.
//!
//! Privilege rules, same as everywhere on this boundary:
//! - the PRIVATE key never leaves the delegate; what crosses to the webview
//!   is the public key, the key version, and status strings;
//! - the passphrase-sealed recovery artifact is written/read by RUST at a
//!   caller-chosen path — its bytes never transit the webview;
//! - signing stays Rust-internal (`sign` is pub(crate) for future
//!   Community services, not a Tauri command).
//!
//! Wire pin: `InMsg`/`OutMsg` are bincode enums whose VARIANT ORDER must
//! match research/freenet-f1/identity-delegate/src/lib.rs exactly — bincode
//! encodes the variant index, so reordering is a silent protocol break.

use freenet_adapter::FreenetAdapter;
use serde::{Deserialize, Serialize};

use crate::state::AppState;

const DELEGATE_WASM: &[u8] = include_bytes!("../assets/identity_delegate.wasm");
const DELEGATE_PARAMS: &[u8] = b"soulstream-identity-v1";

/// Recovery-artifact KDF defaults: Argon2id inside the delegate's wasm.
/// 64 MiB / 3 passes measured comfortably inside the delegate's caps
/// (8–64 MiB, t ≤ 8 — F1). The artifact itself is 93 bytes.
const EXPORT_M_COST_KIB: u32 = 64 * 1024;
const EXPORT_T_COST: u32 = 3;

// ---- delegate protocol (bincode; variant order is the wire) ----

#[derive(Debug, Serialize, Deserialize)]
enum InMsg {
    CreateIdentity { force: bool },
    GetPublicKey,
    Sign { domain: String, payload: Vec<u8> },
    ExportIdentity { passphrase: String, m_cost_kib: u32, t_cost: u32 },
    ImportIdentity { artifact: Vec<u8>, passphrase: String, force: bool },
    RotateIdentity,
    GetTransition,
    RemoveIdentity,
}

#[derive(Debug, Serialize, Deserialize)]
enum OutMsg {
    Identity { public_key: [u8; 32], key_version: u32, created: bool },
    NotInitialized,
    Signature { public_key: [u8; 32], key_version: u32, sig: Vec<u8> },
    Artifact { bytes: Vec<u8> },
    Rotated { old_public: [u8; 32], new_public: [u8; 32], key_version: u32, transition_sig: Vec<u8> },
    Transition { old_public: [u8; 32], new_public: [u8; 32], key_version: u32, transition_sig: Vec<u8> },
    NoTransition,
    Removed,
    Refused { reason: String },
}

// ---- public shapes (webview-safe: public data only) ----

#[derive(Debug, Clone, Serialize)]
pub struct PersonaInfo {
    pub public_key: String,
    pub key_version: u32,
}

#[derive(Debug, Serialize)]
pub struct PersonaStatus {
    /// Adapter reachable and enabled — persona ops can run at all.
    pub available: bool,
    pub adapter: freenet_adapter::AdapterStatus,
    /// None when available but no identity exists yet.
    pub persona: Option<PersonaInfo>,
    /// This build's delegate generation (b58 key) — diagnostics, and the
    /// value that must not drift between releases.
    pub delegate_key: String,
}

#[derive(Debug, Serialize)]
pub struct RotationInfo {
    pub old_public: String,
    pub new_public: String,
    pub key_version: u32,
}

// ---- core (adapter-facing, testable without Tauri) ----

async fn call(adapter: &FreenetAdapter, msg: InMsg) -> Result<OutMsg, String> {
    // Registration is idempotent and cheap; doing it per-op means the
    // service self-heals across node restarts and adapter reconnects.
    adapter
        .delegate_register(DELEGATE_WASM.to_vec(), DELEGATE_PARAMS)
        .await
        .map_err(|e| e.to_string())?;
    let payload = bincode::serialize(&msg).map_err(|e| e.to_string())?;
    let reply = adapter
        .delegate_message(DELEGATE_WASM.to_vec(), DELEGATE_PARAMS, payload)
        .await
        .map_err(|e| e.to_string())?;
    bincode::deserialize(&reply).map_err(|e| format!("delegate reply did not decode: {e}"))
}

fn info(public_key: [u8; 32], key_version: u32) -> PersonaInfo {
    PersonaInfo {
        public_key: bs58::encode(public_key).into_string(),
        key_version,
    }
}

pub(crate) async fn current(adapter: &FreenetAdapter) -> Result<Option<PersonaInfo>, String> {
    match call(adapter, InMsg::GetPublicKey).await? {
        OutMsg::Identity { public_key, key_version, .. } => Ok(Some(info(public_key, key_version))),
        OutMsg::NotInitialized => Ok(None),
        OutMsg::Refused { reason } => Err(reason),
        other => Err(format!("unexpected delegate reply: {other:?}")),
    }
}

pub(crate) async fn create(adapter: &FreenetAdapter) -> Result<PersonaInfo, String> {
    match call(adapter, InMsg::CreateIdentity { force: false }).await? {
        OutMsg::Identity { public_key, key_version, .. } => Ok(info(public_key, key_version)),
        OutMsg::Refused { reason } => Err(reason),
        other => Err(format!("unexpected delegate reply: {other:?}")),
    }
}

/// Seal the identity to a passphrase and write the artifact at `path`.
/// The bytes go disk-direct from Rust; nothing crosses the webview.
pub(crate) async fn export_to(
    adapter: &FreenetAdapter,
    passphrase: &str,
    path: &str,
) -> Result<usize, String> {
    match call(
        adapter,
        InMsg::ExportIdentity {
            passphrase: passphrase.to_string(),
            m_cost_kib: EXPORT_M_COST_KIB,
            t_cost: EXPORT_T_COST,
        },
    )
    .await?
    {
        OutMsg::Artifact { bytes } => {
            let n = bytes.len();
            std::fs::write(path, bytes).map_err(|e| format!("writing artifact: {e}"))?;
            Ok(n)
        }
        OutMsg::NotInitialized => Err("no persona exists yet".into()),
        OutMsg::Refused { reason } => Err(reason),
        other => Err(format!("unexpected delegate reply: {other:?}")),
    }
}

/// Restore from a recovery artifact file. Refuses to overwrite an existing
/// persona unless `force` — same trust-reset semantics the F1 record set.
pub(crate) async fn import_from(
    adapter: &FreenetAdapter,
    passphrase: &str,
    path: &str,
    force: bool,
) -> Result<PersonaInfo, String> {
    let artifact = std::fs::read(path).map_err(|e| format!("reading artifact: {e}"))?;
    match call(
        adapter,
        InMsg::ImportIdentity { artifact, passphrase: passphrase.to_string(), force },
    )
    .await?
    {
        OutMsg::Identity { public_key, key_version, .. } => Ok(info(public_key, key_version)),
        OutMsg::Refused { reason } => Err(reason),
        other => Err(format!("unexpected delegate reply: {other:?}")),
    }
}

pub(crate) async fn rotate(adapter: &FreenetAdapter) -> Result<RotationInfo, String> {
    match call(adapter, InMsg::RotateIdentity).await? {
        OutMsg::Rotated { old_public, new_public, key_version, .. } => Ok(RotationInfo {
            old_public: bs58::encode(old_public).into_string(),
            new_public: bs58::encode(new_public).into_string(),
            key_version,
        }),
        OutMsg::NotInitialized => Err("no persona exists yet".into()),
        OutMsg::Refused { reason } => Err(reason),
        other => Err(format!("unexpected delegate reply: {other:?}")),
    }
}

pub(crate) async fn remove(adapter: &FreenetAdapter) -> Result<(), String> {
    match call(adapter, InMsg::RemoveIdentity).await? {
        OutMsg::Removed => Ok(()),
        OutMsg::Refused { reason } => Err(reason),
        other => Err(format!("unexpected delegate reply: {other:?}")),
    }
}

/// Domain-separated signing for the Rust services (profiles today;
/// playlists, links next). Deliberately not a Tauri command.
pub(crate) async fn sign(
    adapter: &FreenetAdapter,
    domain: &str,
    payload: Vec<u8>,
) -> Result<Vec<u8>, String> {
    match call(adapter, InMsg::Sign { domain: domain.to_string(), payload }).await? {
        OutMsg::Signature { sig, .. } => Ok(sig),
        OutMsg::NotInitialized => Err("no persona exists yet".into()),
        OutMsg::Refused { reason } => Err(reason),
        other => Err(format!("unexpected delegate reply: {other:?}")),
    }
}

// ---- Tauri surface ----

#[tauri::command]
pub async fn persona_status(state: tauri::State<'_, AppState>) -> Result<PersonaStatus, String> {
    let adapter = state.freenet.clone();
    let delegate_key = FreenetAdapter::delegate_key_b58(DELEGATE_WASM.to_vec(), DELEGATE_PARAMS);
    let adapter_status = adapter.status();
    let available = adapter.is_enabled()
        && adapter_status == freenet_adapter::AdapterStatus::Connected;
    let persona = if available { current(&adapter).await.ok().flatten() } else { None };
    Ok(PersonaStatus { available, adapter: adapter_status, persona, delegate_key })
}

#[tauri::command]
pub async fn persona_create(
    app: tauri::AppHandle,
    state: tauri::State<'_, AppState>,
) -> Result<PersonaInfo, String> {
    let info = create(&state.freenet.clone()).await?;
    // Minted here: the profile ledger knows nothing can exist on the
    // network yet, so no search is ever spent looking for it.
    crate::profile::ledger_note_persona(&app, &info.public_key, true);
    Ok(info)
}

#[tauri::command]
pub async fn persona_export(
    state: tauri::State<'_, AppState>,
    passphrase: String,
    path: String,
) -> Result<usize, String> {
    export_to(&state.freenet.clone(), &passphrase, &path).await
}

#[tauri::command]
pub async fn persona_import(
    app: tauri::AppHandle,
    state: tauri::State<'_, AppState>,
    passphrase: String,
    path: String,
    force: bool,
) -> Result<PersonaInfo, String> {
    let info = import_from(&state.freenet.clone(), &passphrase, &path, force).await?;
    // Imported: another device may have published — the first read asks.
    crate::profile::ledger_note_persona(&app, &info.public_key, false);
    Ok(info)
}

#[tauri::command]
pub async fn persona_rotate(
    app: tauri::AppHandle,
    state: tauri::State<'_, AppState>,
) -> Result<RotationInfo, String> {
    let info = rotate(&state.freenet.clone()).await?;
    // A new key addresses a new profile contract: nothing published there yet.
    crate::profile::ledger_note_persona(&app, &info.new_public, true);
    crate::profile::ledger_forget_persona(&app, &info.old_public);
    Ok(info)
}

#[tauri::command]
pub async fn persona_remove(
    app: tauri::AppHandle,
    state: tauri::State<'_, AppState>,
) -> Result<(), String> {
    let adapter = state.freenet.clone();
    let gone = current(&adapter).await.ok().flatten();
    remove(&adapter).await?;
    if let Some(info) = gone {
        crate::profile::ledger_forget_persona(&app, &info.public_key);
    }
    Ok(())
}

// ---- tests ----

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

    #[test]
    fn wire_shapes_roundtrip() {
        // The variant ORDER is the wire; this pins encode/decode symmetry
        // for the message we depend on most.
        let msg = InMsg::ImportIdentity {
            artifact: vec![1, 2, 3],
            passphrase: "pw".into(),
            force: true,
        };
        let bytes = bincode::serialize(&msg).unwrap();
        // Variant index 4 (0-based) leads the encoding as a u32.
        assert_eq!(&bytes[..4], &4u32.to_le_bytes());
        let out = OutMsg::Identity { public_key: [7; 32], key_version: 3, created: false };
        let bytes = bincode::serialize(&out).unwrap();
        let back: OutMsg = bincode::deserialize(&bytes).unwrap();
        assert!(matches!(back, OutMsg::Identity { key_version: 3, .. }));
    }

    #[test]
    fn bundled_delegate_generation_is_pinned() {
        // If this changes, a migration event is happening — see the module
        // docs. Update deliberately, never in passing.
        let key = FreenetAdapter::delegate_key_b58(DELEGATE_WASM.to_vec(), DELEGATE_PARAMS);
        // The gen-2 identity delegate — the generation every F2→F2b spike
        // validated (research/freenet-f1's upgrade probe minted it).
        assert_eq!(key, "EtHTvPUtxbZ8TXGZJrmkj21xjQNqVmWdWAohVgydBgst");
        assert_eq!(DELEGATE_WASM.len(), 202026);
    }

    #[tokio::test]
    async fn ops_refuse_while_disabled() {
        let adapter = FreenetAdapter::default();
        let err = current(&adapter).await.unwrap_err();
        assert!(err.contains("disabled"), "{err}");
    }

    /// Live: needs a local freenet node on 7509.
    ///   cargo test -p app --release persona_live -- --ignored
    /// Mutates the node's persona namespace (create/remove/rotate) — run
    /// against a throwaway node, not one holding an identity you keep.
    #[tokio::test]
    #[ignore = "needs a local freenet node on 7509; mutates its persona"]
    async fn persona_live_full_loop() {
        let adapter = FreenetAdapter::default();
        adapter.enable();
        let mut tries = 0;
        while adapter.status() != freenet_adapter::AdapterStatus::Connected {
            tokio::time::sleep(std::time::Duration::from_millis(200)).await;
            tries += 1;
            assert!(tries < 50, "adapter never connected: {:?}", adapter.status());
        }

        // Clean slate, then the full lifecycle.
        let _ = remove(&adapter).await;
        assert!(current(&adapter).await.unwrap().is_none());
        let created = create(&adapter).await.expect("create");
        assert_eq!(created.key_version, 1);
        // No silent overwrite.
        let dup = create(&adapter).await;
        assert!(dup.is_err());

        // Export → remove → import reproduces the fingerprint.
        let dir = std::env::temp_dir().join("soulstream-persona-test");
        std::fs::create_dir_all(&dir).unwrap();
        let path = dir.join("recovery.ssid");
        let path_str = path.to_string_lossy().to_string();
        let n = export_to(&adapter, "correct horse battery", &path_str).await.expect("export");
        assert_eq!(n, 93, "the artifact is 93 bytes by construction");
        remove(&adapter).await.expect("remove");
        let restored = import_from(&adapter, "correct horse battery", &path_str, false)
            .await
            .expect("import");
        assert_eq!(restored.public_key, created.public_key);
        // Wrong passphrase refuses.
        let bad = import_from(&adapter, "wrong passphrase!", &path_str, true).await;
        assert!(bad.is_err());

        // Rotation bumps the version and changes the key.
        let rot = rotate(&adapter).await.expect("rotate");
        assert_eq!(rot.old_public, created.public_key);
        assert_eq!(rot.key_version, 2);
        let now = current(&adapter).await.unwrap().unwrap();
        assert_eq!(now.public_key, rot.new_public);

        // Signing works for Rust callers under an allowed domain.
        let sig = sign(&adapter, "soulstream.profile/v1", b"payload".to_vec())
            .await
            .expect("sign");
        assert_eq!(sig.len(), 64);
        // ...and refuses an unapproved domain with a typed reason.
        let refused = sign(&adapter, "evil.domain/v1", b"payload".to_vec()).await;
        assert!(refused.is_err());

        adapter.disable();
        let _ = std::fs::remove_file(&path);
    }
}