path: root/libpanto-c/src/lib.zig

const std = @import("std");
const allocator = std.heap.c_allocator;

const panto = @import("panto");

var threaded: ?std.Io.Threaded = null;
threadlocal var last_error: ?[]u8 = null;

const PantoAgent = opaque {};
const PantoStream = opaque {};
const PantoConversation = opaque {};
const PantoSession = opaque {};
const PantoSessionStore = opaque {};

const AgentHandle = struct { agent: *panto.Agent, config: *panto.Config };
const ConversationHandle = struct { conversation: panto.Conversation };
const SessionHandle = struct { session: panto.Session, owns_info: bool = true };
const StoreHandle = struct { ctx: *anyopaque, vtable: *const PantoSessionStoreVTable };

pub const PantoSlice = extern struct { ptr: ?[*]const u8, len: usize };
pub const PantoStatus = enum(c_int) { ok = 0, err = 1 };
pub const PantoNextStatus = enum(c_int) { event = 0, done = 1, err = 2 };
pub const PantoAPIStyle = enum(c_int) { openai_chat = 0, anthropic_messages = 1 };
pub const PantoReasoningEffort = enum(c_int) { default = 0, off, minimal, low, medium, high };
pub const PantoThinking = enum(c_int) { disabled = 0, enabled, adaptive };
pub const PantoEffort = enum(c_int) { low = 0, medium, high, xhigh, max };
pub const PantoMessageRole = enum(c_int) { system = 0, user, assistant };
pub const PantoContentBlockTag = enum(c_int) { Text = 0, Thinking, ToolUse, ToolResult, System, CompactionSummary };
pub const PantoSystemMode = enum(c_int) { append = 0, replace };
pub const PantoEventTag = enum(c_int) { message_start = 0, block_start, tool_details, content_delta, block_complete, message_complete, provider_retry, tool_dispatch_start, tool_dispatch_complete, turn_complete };

pub const PantoUsage = extern struct { input: u64, output: u64, cache_read: u64, cache_write: u64, reasoning: u64 };
pub const PantoSessionInfo = extern struct { id: PantoSlice, created: PantoSlice, modified: PantoSlice, last_user_message: PantoSlice, base_url: PantoSlice, model: PantoSlice, message_count: usize, api_style: PantoAPIStyle, reasoning: PantoReasoningEffort };
pub const PantoSessionInfoList = extern struct { ptr: ?[*]PantoSessionInfo, len: usize };
pub const PantoSessionResult = extern struct { found: bool, session: ?*PantoSession };
pub const PantoOpenAIChatConfig = extern struct { api_key: PantoSlice, base_url: PantoSlice, model: PantoSlice, reasoning: PantoReasoningEffort, max_tokens: u32 };
pub const PantoAnthropicMessagesConfig = extern struct { api_key: PantoSlice, base_url: PantoSlice, model: PantoSlice, api_version: PantoSlice, max_tokens: u32, thinking: PantoThinking, effort: PantoEffort, has_thinking_budget_tokens: bool, thinking_budget_tokens: u32, thinking_interleaved: bool };
pub const PantoProviderConfig = extern struct { tag: PantoAPIStyle, data: extern union { openai_chat: PantoOpenAIChatConfig, anthropic_messages: PantoAnthropicMessagesConfig } };
pub const PantoCompactionConfig = extern struct { keep_verbatim: u32, has_model: bool, model: PantoProviderConfig, has_compaction_prompt: bool, compaction_prompt: PantoSlice };
pub const PantoRetryConfig = extern struct { max_attempts: usize, initial_delay_ms: u64, max_delay_ms: u64, multiplier: f64, jitter: bool };
pub const PantoConfig = extern struct { provider: PantoProviderConfig, compaction: PantoCompactionConfig, retry: PantoRetryConfig };

pub const PantoBlockStart = extern struct { block_type: PantoContentBlockTag, index: usize };
pub const PantoToolDetails = extern struct { index: usize, id: PantoSlice, name: PantoSlice };
pub const PantoContentDelta = extern struct { index: usize, delta: PantoSlice };
pub const PantoBlockComplete = extern struct { index: usize, block_type: PantoContentBlockTag };
pub const PantoMessageComplete = extern struct { has_usage: bool, usage: PantoUsage };
pub const PantoProviderRetry = extern struct { attempt: usize, max_attempts: usize, delay_ms: u64, error_name: PantoSlice, has_status_code: bool, status_code: u16, has_retry_after_ms: bool, retry_after_ms: u64, message: PantoSlice, compaction: bool };
pub const PantoToolDispatchStart = extern struct { count: usize };
pub const PantoToolDispatchComplete = extern struct { message_index: usize };
pub const PantoEvent = extern struct { tag: PantoEventTag, data: extern union { message_start: PantoMessageRole, block_start: PantoBlockStart, tool_details: PantoToolDetails, content_delta: PantoContentDelta, block_complete: PantoBlockComplete, message_complete: PantoMessageComplete, provider_retry: PantoProviderRetry, tool_dispatch_start: PantoToolDispatchStart, tool_dispatch_complete: PantoToolDispatchComplete } };
pub const PantoPersistentMessage = extern struct { role: PantoMessageRole, has_usage: bool, usage: PantoUsage, has_metadata: bool, metadata: PantoSlice };
pub const PantoSessionStoreVTable = extern struct {
    create: *const fn (*anyopaque, **PantoSession) callconv(.c) PantoStatus,
    list: *const fn (*anyopaque, *PantoSessionInfoList) callconv(.c) PantoStatus,
    free_session_infos: *const fn (*anyopaque, PantoSessionInfoList) callconv(.c) void,
    resolve: *const fn (*anyopaque, PantoSlice, *PantoSessionResult) callconv(.c) PantoStatus,
    latest: *const fn (*anyopaque, *PantoSessionResult) callconv(.c) PantoStatus,
    load: *const fn (*anyopaque, PantoSlice, **PantoConversation) callconv(.c) PantoStatus,
    append_messages: *const fn (*anyopaque, PantoSlice, [*]const PantoPersistentMessage, usize) callconv(.c) PantoStatus,
    destroy: ?*const fn (*anyopaque) callconv(.c) void,
};

fn setErr(comptime fmt: []const u8, args: anytype) PantoStatus {
    setErrVoid(fmt, args);
    return .err;
}
fn setErrNext(comptime fmt: []const u8, args: anytype) PantoNextStatus {
    setErrVoid(fmt, args);
    return .err;
}
fn setErrVoid(comptime fmt: []const u8, args: anytype) void {
    if (last_error) |e| allocator.free(e);
    last_error = std.fmt.allocPrint(allocator, fmt, args) catch null;
}
fn slice(s: PantoSlice) []const u8 {
    return if (s.ptr) |p| p[0..s.len] else &.{};
}
fn outSlice(s: []const u8) PantoSlice {
    return .{ .ptr = s.ptr, .len = s.len };
}
fn dupSlice(s: PantoSlice) ![]u8 {
    return allocator.dupe(u8, slice(s));
}
fn dupOut(s: []const u8) !PantoSlice {
    return outSlice(try allocator.dupe(u8, s));
}
fn cloneSessionInfo(info: PantoSessionInfo) !panto.SessionInfo {
    return .{ .id = try dupSlice(info.id), .created = try dupSlice(info.created), .modified = try dupSlice(info.modified), .message_count = info.message_count, .last_user_message = try dupSlice(info.last_user_message), .api_style = @enumFromInt(@intFromEnum(info.api_style)), .base_url = try dupSlice(info.base_url), .model = try dupSlice(info.model), .reasoning = @enumFromInt(@intFromEnum(info.reasoning)) };
}
fn marshalSessionInfo(info: panto.SessionInfo) !PantoSessionInfo {
    return .{ .id = try dupOut(info.id), .created = try dupOut(info.created), .modified = try dupOut(info.modified), .last_user_message = try dupOut(info.last_user_message), .base_url = try dupOut(info.base_url), .model = try dupOut(info.model), .message_count = info.message_count, .api_style = @enumFromInt(@intFromEnum(info.api_style)), .reasoning = @enumFromInt(@intFromEnum(info.reasoning)) };
}
fn freePantoSessionInfo(info: PantoSessionInfo) void { freePS(info.id); freePS(info.created); freePS(info.modified); freePS(info.last_user_message); freePS(info.base_url); freePS(info.model); }
fn wrapSession(session: panto.Session, owns_info: bool) !*PantoSession { const h = try allocator.create(SessionHandle); h.* = .{ .session = session, .owns_info = owns_info }; return @ptrCast(h); }
fn unwrapStore(store: *PantoSessionStore) panto.SessionStore { return .{ .ptr = store, .vtable = &c_store_vtable }; }

export fn panto_init() void {
    if (threaded == null) {
        threaded = std.Io.Threaded.init(allocator, .{});
        panto.init(allocator, threaded.?.io());
    }
}
export fn panto_deinit() void {
    panto.deinit();
    if (threaded) |*t| t.deinit();
    threaded = null;
}
export fn panto_last_error() PantoSlice {
    return if (last_error) |e| outSlice(e) else .{ .ptr = null, .len = 0 };
}
export fn panto_error_free(s: PantoSlice) void {
    if (s.ptr) |p| allocator.free(@constCast(p[0..s.len]));
}

export fn panto_conversation_create(out: **PantoConversation) PantoStatus {
    const h = allocator.create(ConversationHandle) catch return setErr("OutOfMemory", .{});
    h.* = .{ .conversation = panto.Conversation.init(allocator) };
    out.* = @ptrCast(h);
    return .ok;
}
export fn panto_conversation_destroy(c: ?*PantoConversation) void {
    if (c) |ptr| {
        const h: *ConversationHandle = @ptrCast(@alignCast(ptr));
        h.conversation.deinit();
        allocator.destroy(h);
    }
}
export fn panto_session_create_null(out: **PantoSession) PantoStatus {
    const h = allocator.create(SessionHandle) catch return setErr("OutOfMemory", .{});
    var ns = panto.NullStore.init(allocator);
    h.* = .{ .session = ns.store().create() };
    out.* = @ptrCast(h);
    return .ok;
}
export fn panto_session_create(store: *PantoSessionStore, info: PantoSessionInfo, out: **PantoSession) PantoStatus {
    const cloned = cloneSessionInfo(info) catch |e| return setErr("{t}", .{e});
    out.* = wrapSession(.{ .info = cloned, .store = unwrapStore(store) }, true) catch |e| return setErr("{t}", .{e});
    return .ok;
}
export fn panto_session_destroy(s: ?*PantoSession) void {
    if (s) |ptr| {
        const h: *SessionHandle = @ptrCast(@alignCast(ptr));
        if (h.owns_info) h.session.info.deinit(allocator);
        allocator.destroy(h);
    }
}
export fn panto_session_store_create(ctx: *anyopaque, vt: *const PantoSessionStoreVTable, out: **PantoSessionStore) PantoStatus {
    const h = allocator.create(StoreHandle) catch return setErr("OutOfMemory", .{});
    h.* = .{ .ctx = ctx, .vtable = vt };
    out.* = @ptrCast(h);
    return .ok;
}
export fn panto_session_store_destroy(store: ?*PantoSessionStore) void {
    if (store) |ptr| { const h: *StoreHandle = @ptrCast(@alignCast(ptr)); if (h.vtable.destroy) |d| d(h.ctx); allocator.destroy(h); }
}
export fn panto_session_store_create_session(store: *PantoSessionStore, out: **PantoSession) PantoStatus { return cStoreCreate(store, out); }
export fn panto_session_store_list(store: *PantoSessionStore, out: *PantoSessionInfoList) PantoStatus { return cStoreList(store, out); }
export fn panto_session_info_list_destroy(infos: PantoSessionInfoList) void { if (infos.ptr) |p| { for (p[0..infos.len]) |info| freePantoSessionInfo(info); allocator.free(p[0..infos.len]); } }
export fn panto_session_store_resolve(store: *PantoSessionStore, id: PantoSlice, out: *PantoSessionResult) PantoStatus { return cStoreResolve(store, id, out); }
export fn panto_session_store_latest(store: *PantoSessionStore, out: *PantoSessionResult) PantoStatus { return cStoreLatest(store, out); }
export fn panto_session_load(session: *PantoSession, out: **PantoConversation) PantoStatus {
    const h: *SessionHandle = @ptrCast(@alignCast(session));
    const conv = h.session.load() catch |e| return setErr("{t}", .{e});
    const ch = allocator.create(ConversationHandle) catch return setErr("OutOfMemory", .{});
    ch.* = .{ .conversation = conv };
    out.* = @ptrCast(ch);
    return .ok;
}

fn convertConfig(c: *const PantoConfig) !*panto.Config {
    const out = try allocator.create(panto.Config);
    errdefer allocator.destroy(out);
    out.* = .{ .provider = try convertProvider(c.provider), .compaction = .{ .keep_verbatim = c.compaction.keep_verbatim, .model = if (c.compaction.has_model) try convertProvider(c.compaction.model) else null, .compaction_prompt = if (c.compaction.has_compaction_prompt) try dupSlice(c.compaction.compaction_prompt) else null }, .retry = .{ .max_attempts = c.retry.max_attempts, .initial_delay_ms = c.retry.initial_delay_ms, .max_delay_ms = c.retry.max_delay_ms, .multiplier = c.retry.multiplier, .jitter = c.retry.jitter } };
    return out;
}
fn convertProvider(p: PantoProviderConfig) !panto.ProviderConfig {
    return switch (p.tag) {
        .openai_chat => .{ .openai_chat = .{ .api_key = try dupSlice(p.data.openai_chat.api_key), .base_url = try dupSlice(p.data.openai_chat.base_url), .model = try dupSlice(p.data.openai_chat.model), .reasoning = @enumFromInt(@intFromEnum(p.data.openai_chat.reasoning)), .max_tokens = p.data.openai_chat.max_tokens } },
        .anthropic_messages => .{ .anthropic_messages = .{ .api_key = try dupSlice(p.data.anthropic_messages.api_key), .base_url = try dupSlice(p.data.anthropic_messages.base_url), .model = try dupSlice(p.data.anthropic_messages.model), .api_version = if (p.data.anthropic_messages.api_version.len == 0) "2023-06-01" else try dupSlice(p.data.anthropic_messages.api_version), .max_tokens = p.data.anthropic_messages.max_tokens, .thinking = @enumFromInt(@intFromEnum(p.data.anthropic_messages.thinking)), .effort = @enumFromInt(@intFromEnum(p.data.anthropic_messages.effort)), .thinking_budget_tokens = if (p.data.anthropic_messages.has_thinking_budget_tokens) p.data.anthropic_messages.thinking_budget_tokens else null, .thinking_interleaved = p.data.anthropic_messages.thinking_interleaved } },
    };
}
fn freeConfig(c: *panto.Config) void {
    freeProvider(&c.provider);
    if (c.compaction.model) |*m| freeProvider(m);
    if (c.compaction.compaction_prompt) |s| allocator.free(s);
    allocator.destroy(c);
}
fn freeProvider(pv: *panto.ProviderConfig) void {
    switch (pv.*) {
        .openai_chat => |c| {
            allocator.free(c.api_key);
            allocator.free(c.base_url);
            allocator.free(c.model);
        },
        .anthropic_messages => |c| {
            allocator.free(c.api_key);
            allocator.free(c.base_url);
            allocator.free(c.model);
            if (c.api_version.ptr != "2023-06-01".ptr) allocator.free(c.api_version);
        },
    }
}

fn cStoreCreate(ctx: *anyopaque, out: **PantoSession) PantoStatus { const h: *StoreHandle = @ptrCast(@alignCast(ctx)); return h.vtable.create(h.ctx, out); }
fn cStoreList(ctx: *anyopaque, out: *PantoSessionInfoList) PantoStatus { const h: *StoreHandle = @ptrCast(@alignCast(ctx)); return h.vtable.list(h.ctx, out); }
fn cStoreResolve(ctx: *anyopaque, id: PantoSlice, out: *PantoSessionResult) PantoStatus { const h: *StoreHandle = @ptrCast(@alignCast(ctx)); return h.vtable.resolve(h.ctx, id, out); }
fn cStoreLatest(ctx: *anyopaque, out: *PantoSessionResult) PantoStatus { const h: *StoreHandle = @ptrCast(@alignCast(ctx)); return h.vtable.latest(h.ctx, out); }
fn cStoreLoad(ctx: *anyopaque, id: []const u8) anyerror!?panto.Conversation { const h: *StoreHandle = @ptrCast(@alignCast(ctx)); var out: *PantoConversation = undefined; if (h.vtable.load(h.ctx, outSlice(id), &out) != .ok) return error.CStoreLoadFailed; const ch: *ConversationHandle = @ptrCast(@alignCast(out)); const conv = ch.conversation; ch.conversation = panto.Conversation.init(allocator); panto_conversation_destroy(out); return conv; }
fn cStoreAppend(ctx: *anyopaque, session_id: []const u8, messages: []panto.PersistentMessage) anyerror!void { const h: *StoreHandle = @ptrCast(@alignCast(ctx)); const cmsgs = try allocator.alloc(PantoPersistentMessage, messages.len); defer allocator.free(cmsgs); for (messages, 0..) |m, i| cmsgs[i] = .{ .role = @enumFromInt(@intFromEnum(m.message.role)), .has_usage = m.usage != null, .usage = if (m.usage) |u| usage(u) else .{ .input = 0, .output = 0, .cache_read = 0, .cache_write = 0, .reasoning = 0 }, .has_metadata = m.message.metadata != null, .metadata = outSlice(m.message.metadata orelse "") }; if (h.vtable.append_messages(h.ctx, outSlice(session_id), cmsgs.ptr, cmsgs.len) != .ok) return error.CStoreAppendFailed; }
fn cStoreListZ(ctx: *anyopaque) anyerror![]panto.SessionInfo {
    const h: *StoreHandle = @ptrCast(@alignCast(ctx));
    var list: PantoSessionInfoList = undefined;
    if (h.vtable.list(h.ctx, &list) != .ok) return error.CStoreListFailed;
    defer h.vtable.free_session_infos(h.ctx, list);
    const out = try allocator.alloc(panto.SessionInfo, list.len);
    errdefer allocator.free(out);
    if (list.ptr) |p| {
        for (p[0..list.len], 0..) |info, i| out[i] = try cloneSessionInfo(info);
    }
    return out;
}
fn cStoreFreeInfos(_: *anyopaque, infos: []panto.SessionInfo) void { for (infos) |info| info.deinit(allocator); allocator.free(infos); }
fn cStoreResolveZ(ctx: *anyopaque, id: []const u8) anyerror!?panto.Session { const h: *StoreHandle = @ptrCast(@alignCast(ctx)); var res: PantoSessionResult = undefined; if (h.vtable.resolve(h.ctx, outSlice(id), &res) != .ok) return error.CStoreResolveFailed; if (!res.found) return null; const sh: *SessionHandle = @ptrCast(@alignCast(res.session.?)); return sh.session; }
fn cStoreLatestZ(ctx: *anyopaque) anyerror!?panto.Session { const h: *StoreHandle = @ptrCast(@alignCast(ctx)); var res: PantoSessionResult = undefined; if (h.vtable.latest(h.ctx, &res) != .ok) return error.CStoreLatestFailed; if (!res.found) return null; const sh: *SessionHandle = @ptrCast(@alignCast(res.session.?)); return sh.session; }
fn cStoreCreateZ(ctx: *anyopaque) panto.Session {
    var out: *PantoSession = undefined;
    if (cStoreCreate(ctx, &out) != .ok) {
        var ns = panto.NullStore.init(allocator);
        return ns.store().create();
    }
    const sh: *SessionHandle = @ptrCast(@alignCast(out));
    return sh.session;
}
const c_store_vtable: panto.SessionStore.VTable = .{ .create = cStoreCreateZ, .list = cStoreListZ, .freeSessionInfos = cStoreFreeInfos, .resolve = cStoreResolveZ, .latest = cStoreLatestZ, .load = cStoreLoad, .appendMessages = cStoreAppend };

export fn panto_agent_create(c: *const PantoConfig, s: ?*PantoSession, conv: ?*PantoConversation, out: **PantoAgent) PantoStatus {
    const cfg = convertConfig(c) catch |e| return setErr("{t}", .{e});
    const sess = if (s) |sp| blk: {
        const sh: *SessionHandle = @ptrCast(@alignCast(sp));
        sh.owns_info = false;
        break :blk sh.session;
    } else blk: {
        var ns = panto.NullStore.init(allocator);
        break :blk ns.store().create();
    };
    var maybe_conv: ?panto.Conversation = null;
    if (conv) |cp| {
        const ch: *ConversationHandle = @ptrCast(@alignCast(cp));
        maybe_conv = ch.conversation;
        ch.conversation = panto.Conversation.init(allocator);
    }
    const a = panto.Agent.init(allocator, threaded.?.io(), cfg, sess, maybe_conv) catch |e| {
        freeConfig(cfg);
        return setErr("{t}", .{e});
    };
    const h = allocator.create(AgentHandle) catch return setErr("OutOfMemory", .{});
    h.* = .{ .agent = a, .config = cfg };
    out.* = @ptrCast(h);
    return .ok;
}
export fn panto_agent_destroy(a: ?*PantoAgent) void {
    if (a) |ptr| {
        const h: *AgentHandle = @ptrCast(@alignCast(ptr));
        h.agent.deinit();
        freeConfig(h.config);
        allocator.destroy(h);
    }
}
export fn panto_agent_session_id(a: *PantoAgent) PantoSlice {
    const h: *AgentHandle = @ptrCast(@alignCast(a));
    return outSlice(h.agent.sessionId());
}
export fn panto_agent_set_config(a: *PantoAgent, c: *const PantoConfig) PantoStatus {
    const h: *AgentHandle = @ptrCast(@alignCast(a));
    const cfg = convertConfig(c) catch |e| return setErr("{t}", .{e});
    const old = h.config;
    h.config = cfg;
    h.agent.setConfig(cfg);
    freeConfig(old);
    return .ok;
}
export fn panto_agent_add_system_message(a: *PantoAgent, text: PantoSlice) PantoStatus {
    const h: *AgentHandle = @ptrCast(@alignCast(a));
    h.agent.addSystemMessage(slice(text)) catch |e| return setErr("{t}", .{e});
    return .ok;
}
export fn panto_agent_set_system_prompt(a: *PantoAgent, text: PantoSlice) PantoStatus {
    const h: *AgentHandle = @ptrCast(@alignCast(a));
    h.agent.setSystemPrompt(slice(text)) catch |e| return setErr("{t}", .{e});
    return .ok;
}
export fn panto_agent_run(a: *PantoAgent, text: PantoSlice, out: **PantoStream) PantoStatus {
    const h: *AgentHandle = @ptrCast(@alignCast(a));
    const st = h.agent.run(.{ .text = slice(text) }) catch |e| return setErr("{t}", .{e});
    out.* = @ptrCast(st);
    return .ok;
}
export fn panto_stream_destroy(s: ?*PantoStream) void {
    if (s) |ptr| {
        const st: *panto.Stream = @ptrCast(@alignCast(ptr));
        st.deinit();
    }
}
export fn panto_stream_next(s: *PantoStream, out: *PantoEvent) PantoNextStatus {
    const st: *panto.Stream = @ptrCast(@alignCast(s));
    const ev = st.next() catch |e| return setErrNext("{t}", .{e});
    if (ev) |e| {
        out.* = marshalEvent(e) catch |err| return setErrNext("{t}", .{err});
        return .event;
    }
    return .done;
}
export fn panto_event_free(ev: *PantoEvent) void {
    switch (ev.tag) {
        .tool_details => {
            freePS(ev.data.tool_details.id);
            freePS(ev.data.tool_details.name);
        },
        .content_delta => freePS(ev.data.content_delta.delta),
        .provider_retry => {
            freePS(ev.data.provider_retry.error_name);
            freePS(ev.data.provider_retry.message);
        },
        else => {},
    }
    ev.* = undefined;
}
fn freePS(s: PantoSlice) void {
    if (s.ptr) |p| allocator.free(@constCast(p[0..s.len]));
}

fn marshalEvent(ev: panto.Event) !PantoEvent {
    return switch (ev) {
        .message_start => |r| .{ .tag = .message_start, .data = .{ .message_start = @enumFromInt(@intFromEnum(r)) } },
        .block_start => |b| .{ .tag = .block_start, .data = .{ .block_start = .{ .block_type = @enumFromInt(@intFromEnum(b.block_type)), .index = b.index } } },
        .tool_details => |t| .{ .tag = .tool_details, .data = .{ .tool_details = .{ .index = t.index, .id = try dupOut(t.id), .name = try dupOut(t.name) } } },
        .content_delta => |d| .{ .tag = .content_delta, .data = .{ .content_delta = .{ .index = d.index, .delta = try dupOut(d.delta) } } },
        .block_complete => |b| .{ .tag = .block_complete, .data = .{ .block_complete = .{ .index = b.index, .block_type = @enumFromInt(@intFromEnum(b.block)) } } },
        .message_complete => |m| .{ .tag = .message_complete, .data = .{ .message_complete = .{ .has_usage = m.usage != null, .usage = if (m.usage) |u| usage(u) else .{ .input = 0, .output = 0, .cache_read = 0, .cache_write = 0, .reasoning = 0 } } } },
        .provider_retry => |r| .{ .tag = .provider_retry, .data = .{ .provider_retry = .{ .attempt = r.attempt, .max_attempts = r.max_attempts, .delay_ms = r.delay_ms, .error_name = try dupOut(@errorName(r.err)), .has_status_code = r.status_code != null, .status_code = r.status_code orelse 0, .has_retry_after_ms = r.retry_after_ms != null, .retry_after_ms = r.retry_after_ms orelse 0, .message = try dupOut(r.message orelse ""), .compaction = r.compaction } } },
        .tool_dispatch_start => |t| .{ .tag = .tool_dispatch_start, .data = .{ .tool_dispatch_start = .{ .count = t.count } } },
        .tool_dispatch_complete => .{ .tag = .tool_dispatch_complete, .data = .{ .tool_dispatch_complete = .{ .message_index = 0 } } },
        .turn_complete => .{ .tag = .turn_complete, .data = undefined },
    };
}
fn usage(u: panto.Usage) PantoUsage {
    return .{ .input = u.input, .output = u.output, .cache_read = u.cache_read, .cache_write = u.cache_write, .reasoning = u.reasoning };
}

test "c abi exports compile" {
    try std.testing.expect(true);
}