#pragma once

#include <string>

// Persistent node-connectivity banner shown at the top of the content column when the wallet
// cannot reach its node. Distinct from the transient toast notifications: it stays visible for
// as long as the fault persists, so an offline wallet is never silently mistaken for a working
// one. The decision (whether to show, how severe, which action) is a pure function of a state
// snapshot so it can be unit-tested; App::renderNodeStatusBanner() feeds it the live state and
// draws the strip. See src/app.cpp.
namespace dragonx::ui {

// Visual weight. Warning (amber) = recoverable / a reconnect is offered; Error (red) = a hard
// fault the user must act on (the daemon gave up crashing, or a lite wallet failed to open).
enum class NodeBannerSeverity {
    Warning,
    Error,
};

// What the banner's action button does. App maps this to the concrete call.
enum class NodeBannerAction {
    None,            // no button — nothing the user can usefully do from here
    Reconnect,       // full node: re-run the RPC connect state machine (App::tryConnect)
    RestartNode,     // full node: the embedded daemon crashed & auto-restart gave up (App::restartDaemon)
    OpenConfigFolder,// external node: open the folder holding DRAGONX.conf so the user can fix the login
    RecoverLegacyFunds, // a degraded legacy wallet with stuck transparent funds: open migrate-to-seed
};

// Why the banner is up. App maps this to a translated headline; `detail` carries the live,
// already-human-readable status text (connection_status_ / daemon lastError / lite open error).
enum class NodeBannerReason {
    None,
    FullNodeOffline,  // a reachable node was lost, or never came up; reconnect offered
    DaemonCrashed,    // the embedded daemon crashed repeatedly and auto-restart stopped
    LiteOpenFailed,   // lite build: the wallet failed to open
    NoPeers,          // connected to the daemon but no peer-derived tip (0 peers) — stalled, stale
    NodeBusy,         // the node is up but busy (rebuilding witnesses / catching up / not answering)
    AuthFailed,       // the node rejected the wallet's RPC login (bad rpcuser/rpcpassword in the conf)
    LegacyFundsStuck, // a DEGRADED legacy wallet (can't derive a z-address) holding transparent funds it
                      // therefore can't shield/spend — offer the migrate-to-seed recovery
};

struct NodeBannerState {
    bool               show     = false;
    NodeBannerSeverity severity = NodeBannerSeverity::Warning;
    NodeBannerReason   reason   = NodeBannerReason::None;
    NodeBannerAction   action   = NodeBannerAction::None;
    std::string        detail;  // passthrough status/error text (may be empty)
};

// Snapshot of the connection state the banner reads. Plain values so the decision is testable
// without an App instance.
struct NodeBannerInputs {
    bool lite                 = false;  // lite build (no embedded daemon / RPC)
    bool connected            = false;  // state_.connected — the master "online" flag
    bool warming_up           = false;  // daemon reachable, RPC warmup (code -28)
    bool daemon_initializing  = false;  // daemon launching / block index loading
    bool connection_in_progress = false;  // a connect attempt is actively running

    // Peer connectivity: a full node connected to the daemon but with NO peer-derived tip
    // (longestchain == 0 -> tip_known false) has no peers, so it silently stalls at a stale height
    // while balance/sync look "done". `blocks` gates the check so we don't flag the brief window
    // before the first chain-info refresh. (audit: no-peer-banner)
    bool tip_known            = true;   // sync.tip_known — a peer-derived network tip is known
    int  blocks               = 0;      // sync.blocks — >0 once chain info has been fetched

    // Full-node embedded-daemon crash signal.
    bool using_embedded_daemon = false;
    bool has_daemon_controller = false;
    bool daemon_running        = false;
    int  daemon_crash_count    = 0;

    // The node is running but busy with something it can't be interrupted out of (a witness rebuild, the
    // startup replay) or too busy to answer RPC. Wallet data may be stale; a reconnect would only add
    // requests, so the banner offers no action. node_busy_detail is the live, translated description.
    bool        node_busy = false;
    std::string node_busy_detail;

    bool auth_failed = false;        // the node rejected the wallet's RPC login (bad rpcuser/rpcpassword)

    // The wallet opened DEGRADED (no usable HD seed, so z_getnewaddress / shielding fail) AND it holds
    // transparent funds that are therefore stuck. App sets this ONLY from wallet_degraded_ + a transparent
    // balance — never from merely-non-mnemonic status, which is a functional wallet and must not be flagged.
    bool legacy_funds_stuck = false;

    std::string connection_status;  // human-readable status line (already translated)
    std::string daemon_last_error;  // DaemonController::lastError() (may be empty)
    std::string lite_open_error;    // lite: last wallet-open failure reason
};

// Auto-restart give-up threshold — mirrors the crash cap in app_network.cpp's connect loop.
inline constexpr int kNodeBannerCrashGiveUpCount = 3;

inline NodeBannerState evaluateNodeStatusBanner(const NodeBannerInputs& in) {
    NodeBannerState s;

    if (in.lite) {
        // Lite has no daemon/RPC; "online" == wallet open. Only a genuine open failure is a
        // fault worth a persistent banner (a not-yet-created wallet is handled by the normal
        // "No wallet open" prompt, and leaves lite_open_error empty).
        if (!in.connected && !in.lite_open_error.empty()) {
            s.show     = true;
            s.severity = NodeBannerSeverity::Error;
            s.reason   = NodeBannerReason::LiteOpenFailed;
            s.action   = NodeBannerAction::None;
            s.detail   = in.lite_open_error;
        }
        return s;
    }

    // Full node, busy. Before the startup-phase returns below: the overlay sets daemon_initializing while
    // the node is busy too, and the banner must still say why the wallet isn't updating. No action: a
    // "Reconnect" would only queue more requests behind the busy node.
    if (in.node_busy) {
        s.show     = true;
        s.severity = NodeBannerSeverity::Warning;
        s.reason   = NodeBannerReason::NodeBusy;
        s.action   = NodeBannerAction::None;
        s.detail   = in.node_busy_detail;
        return s;
    }

    // Full node. In an expected startup phase → the loading/warmup overlay owns the screen, so no
    // banner. An active connect attempt likewise shows progress, not an error — don't flicker a
    // banner over it. (These return even if `connected` has flipped early, matching prior behavior.)
    if (in.warming_up || in.daemon_initializing) return s;
    if (in.connection_in_progress) return s;

    // Connected to the daemon (RPC works) but with no peer-derived tip → the node has no peers and
    // cannot learn about new blocks; it silently stalls at a stale height while everything looks
    // synced. Surface it as a recoverable warning. A plain reconnect won't help, but restarting the
    // embedded daemon re-triggers peer discovery (it re-reads the -addnode seeds), so offer that when
    // we own the node; an external node is the user's own to restart, so no button there. The detail
    // is left empty: here connection_status is just "Connected", which would contradict the
    // "no peers" headline — App renders a translated, actionable hint for this reason instead.
    if (in.connected) {
        if (!in.tip_known && in.blocks > 0) {
            s.show     = true;
            s.severity = NodeBannerSeverity::Warning;
            s.reason   = NodeBannerReason::NoPeers;
            s.action   = (in.using_embedded_daemon && in.has_daemon_controller)
                             ? NodeBannerAction::RestartNode
                             : NodeBannerAction::None;
            s.detail.clear();
            return s;
        }
        // Connected and synced, but a degraded legacy wallet can't shield its transparent funds. Offer the
        // recovery flow. Checked after NoPeers (can't recover until the node can see the chain anyway).
        if (in.legacy_funds_stuck) {
            s.show     = true;
            s.severity = NodeBannerSeverity::Warning;
            s.reason   = NodeBannerReason::LegacyFundsStuck;
            s.action   = NodeBannerAction::RecoverLegacyFunds;
            s.detail.clear();
        }
        return s;
    }

    // Genuinely offline. Distinguish "the embedded daemon crashed and we stopped retrying" (a
    // hard fault needing a manual restart) from an ordinary lost/failed connection (retryable).
    if (in.using_embedded_daemon && in.has_daemon_controller && !in.daemon_running &&
        in.daemon_crash_count >= kNodeBannerCrashGiveUpCount) {
        s.show     = true;
        s.severity = NodeBannerSeverity::Error;
        s.reason   = NodeBannerReason::DaemonCrashed;
        s.action   = NodeBannerAction::RestartNode;
        s.detail   = !in.daemon_last_error.empty() ? in.daemon_last_error : in.connection_status;
        return s;
    }

    // The node rejected the wallet's RPC login — retrying won't help (the creds are wrong). Restarting
    // the embedded node regenerates its cookie/creds; for an external node the user fixes DRAGONX.conf,
    // so offer to open its folder. App renders a translated, actionable detail (connection_status here
    // is the jargon "Auth failed…" line).
    if (in.auth_failed) {
        s.show     = true;
        s.severity = NodeBannerSeverity::Error;
        s.reason   = NodeBannerReason::AuthFailed;
        s.action   = (in.using_embedded_daemon && in.has_daemon_controller)
                         ? NodeBannerAction::RestartNode
                         : NodeBannerAction::OpenConfigFolder;
        s.detail.clear();
        return s;
    }

    s.show     = true;
    s.severity = NodeBannerSeverity::Warning;
    s.reason   = NodeBannerReason::FullNodeOffline;
    s.action   = NodeBannerAction::Reconnect;
    s.detail   = in.connection_status;
    return s;
}

}  // namespace dragonx::ui