path: root/backend/api/src/req.zig

const z = @import( "std" );
const u = @import( "util.zig" );
const HttpClient = @import( "tls12" );

const ClientResponse = HttpClient.Response;
const ClientRequest = HttpClient.Request;

const ArenaAllocator = z.heap.ArenaAllocator;
const Allocator = z.mem.Allocator;
const print = z.debug.print;

pub const Header = z.http.Header;

pub const OnChunkFunc = *const fn ( []const u8 ) void;
pub fn OnChunkFuncWithData( t: type ) type {
  return *const fn ( []const u8, t ) void;
}
pub const OnReqEndFunc = *const fn( *Result ) void;
pub fn OnReqEndFuncWithData( t: type ) type {
  return *const fn( *Result, t ) void;
}


const ParamsBase = struct {
  url: []const u8,
  body: ?[]const u8 = null,
  method: z.http.Method = z.http.Method.GET,
  headers: ?[]const Header = null,
};

pub fn Params() type {
  return u.MergeTypes( ParamsBase, struct { chunk_fn: ?OnChunkFunc = null } );
}
pub fn ParamsAsync() type {
  return u.MergeTypes( ParamsBase, struct { end_fn: ?OnReqEndFunc = null, chunk_fn: ?OnChunkFunc = null, mutex: z.Thread.Mutex = .{} } );
}
pub fn ParamsWithData( t: type ) type {
  return u.MergeTypes( ParamsBase, struct { chunk_fn: ?OnChunkFuncWithData(t), chunk_data: t = undefined } );
}
pub fn ParamsWithDataAsync( t: type ) type {
  return u.MergeTypes( ParamsBase, struct { end_fn: ?OnReqEndFuncWithData(t), chunk_fn: ?OnChunkFuncWithData(t), chunk_data: t = undefined, mutex: z.Thread.Mutex = .{} } );
}


pub const Result = struct {
  ok: bool = false,
  url: []const u8 = &[_]u8{ 0 },
  status: z.http.Status = z.http.Status.teapot,
  body: ?[]const u8 = null,
  headers: z.ArrayList( z.http.Header ),
  alloc: z.mem.Allocator = undefined,

  pub fn deinit( self: *const Result ) void {
    if( self.body ) |*body|
      self.alloc.free( body.* );

    self.headers.deinit();
  }
};

pub fn send( params: Params(), a: Allocator ) Result {
  var ret = Result{
    .alloc = a,
    .url = params.url,
    .headers = z.ArrayList( Header ).init( a )
  };

  const uri = z.Uri.parse( params.url ) catch return ret;
  var client = HttpClient{ .allocator = a };
  defer client.deinit();

  const header_buf: []u8 = a.alloc( u8, 1024 * 8 ) catch return ret;
  defer a.free( header_buf );

  var req = client.open( params.method, uri, .{
    .server_header_buffer = header_buf
  }) catch |e| { z.debug.print( "{any}\n", .{ e } ); return ret; };
  defer req.deinit();

  if( params.headers ) |hdrs|
    req.extra_headers = hdrs;

  if( params.body != null and params.method == z.http.Method.POST )
    req.transfer_encoding = .{ .content_length = params.body.?.len };

  req.send() catch return ret;
  if( params.body != null and params.method == z.http.Method.POST ) {
    var writer = req.writer();
    writer.writeAll( params.body.? ) catch return ret;
  }
  req.finish() catch return ret;
  req.wait() catch return ret;

  ret.ok = true;
  if( params.chunk_fn != null ) {
    receiveChunked( &ret, &req, params, a ) catch { ret.ok = false; };
  } else {
    receiveSingle( &ret, &req, a ) catch { ret.ok = false; };
  }

  receiveHeaders( &ret, &req );
  return ret;
}

///compared to send, takes an additional data arg that gets passed to the chunk_fn
pub fn sendWithData( t: type, params: ParamsWithData(t), a: Allocator ) Result {
  var ret = Result{
    .alloc = a,
    .url = params.url,
    .headers = z.ArrayList( Header ).init( a )
  };

  const uri = z.Uri.parse( params.url ) catch return ret;
  var client = HttpClient{ .allocator = a };
  defer client.deinit();

  const header_buf: []u8 = a.alloc( u8, 1024 * 8 ) catch return ret;
  defer a.free( header_buf );

  var req = client.open( params.method, uri, .{
    .server_header_buffer = header_buf
  }) catch |e| { z.debug.print( "http error: {any}\n", .{ e } ); return ret; };
  defer req.deinit();

  if( params.headers ) |hdrs|
    req.extra_headers = hdrs;

  if( params.body != null and params.method == z.http.Method.POST )
    req.transfer_encoding = .{ .content_length = params.body.?.len };

  req.send() catch return ret;
  if( params.body != null and params.method == z.http.Method.POST ) {
    var writer = req.writer();
    writer.writeAll( params.body.? ) catch return ret;
  }
  req.finish() catch return ret;
  req.wait() catch return ret;

  receiveHeaders( &ret, &req );
  if( params.chunk_fn != null ) {
    receiveChunkedWithData( t, &ret, &req, params, a ) catch { ret.ok = false; };
  } else {
    receiveSingle( &ret, &req, a ) catch { ret.ok = false; };
  }

  ret.ok = req.response.status == .ok;
  return ret;
}

///UNFINISHED: DOES NOT WORK YET
pub fn dispatchSendWithData( t: type, params: ParamsWithDataAsync(t), _a: ArenaAllocator ) void {
  var arena = _a;
  const a = arena.allocator();
  defer arena.deinit();
  var ret = Result{
    .alloc = a,
    .url = params.url,
    .headers = z.ArrayList( Header ).init( a )
  };

  defer if( params.end_fn ) |f| f( &ret, params.chunk_data );

  const uri = z.Uri.parse( params.url ) catch return;
  var client = HttpClient{ .allocator = a };

  const header_buf: []u8 = a.alloc( u8, 1024 * 8 ) catch return;

  var req = client.open( params.method, uri, .{
    .server_header_buffer = header_buf,
  }) catch |e| { z.debug.print( "http error: {any}\n", .{ e } ); return; };

  if( params.headers ) |hdrs|
    req.extra_headers = hdrs;

  if( params.body != null and params.method == z.http.Method.POST )
    req.transfer_encoding = .{ .content_length = params.body.?.len };

  req.send() catch return;
  if( params.body != null and params.method == z.http.Method.POST ) {
    var writer = req.writer();
    writer.writeAll( params.body.? ) catch return;
  }
  req.finish() catch return;
  req.wait() catch return;

  receiveHeaders( &ret, &req );
  if( params.chunk_fn != null ) {
    receiveChunkedWithDataAsync( t, &ret, &req, params, a ) catch { ret.ok = false; };
  } else {
    receiveSingle( &ret, &req, a ) catch { ret.ok = false; };
  }

  ret.ok = req.response.status == .ok;
}

pub fn sendWithDataAsync( t: type, params: ParamsWithDataAsync(t), _arena: ArenaAllocator ) void {
  var arena = _arena;
  const a = arena.allocator();
  const paramsc = params;

  _=z.Thread.spawn( .{ .allocator = a }, dispatchSendWithData, .{ t, paramsc, arena } ) catch |e| {
    arena.deinit();
    z.debug.print( "error spawning thread: {any}\n", .{ e } ); return;
  };
}

fn receiveHeaders( ret: *Result, req: *ClientRequest ) void {
  var iter = req.response.iterateHeaders();
  while( iter.next() ) |header|
    ret.headers.append( header ) catch continue;
}

fn receiveSingle( ret: *Result, res: *ClientRequest, a: Allocator ) !void {
  ret.status = res.response.status;
  // fuck it we ball
  const slice = try res.reader().readAllAlloc( a, 1024 * 1024 );
  ret.body = slice;
  if( ret.status != .ok )
    ret.ok = false;
}

fn receiveChunked( ret: *Result, req: *ClientRequest, q: Params(), a: Allocator ) !void {
  ret.status = req.response.status;

  var full_str = z.ArrayList( u8 ).init( a );
  defer full_str.deinit();
  const writer = full_str.writer();

  var buf = try a.alloc( u8, 1024 * 16 );
  defer a.free( buf );

  var bytes_total: usize = 0;
  const reader = req.reader();
  while( true ) {
    const bytes_read = try reader.read( buf );
    if( bytes_read == 0 )
      break;

    bytes_total += bytes_read;
    _=try writer.write( buf[0..bytes_read] );
    const f = q.chunk_fn;
    if( f ) |func| func( buf[0..bytes_read] );
    z.Thread.yield() catch {};
  }

  const slice = try a.alloc( u8, bytes_total );
  @memcpy( slice[0..bytes_total], full_str.items[0..bytes_total] );
  ret.body = slice;
}

fn receiveChunkedWithData( t: type, ret: *Result, req: *ClientRequest, q: ParamsWithData(t), a: Allocator ) !void {
  ret.status = req.response.status;

  var full_str = z.ArrayList( u8 ).init( a );
  defer full_str.deinit();
  const writer = full_str.writer();

  var buf = try a.alloc( u8, 1024 * 16 );
  defer a.free( buf );

  var bytes_total: usize = 0;
  const reader = req.reader();

  //todo: throw this into another thread
  while( true ) {
    const bytes_read = try reader.read( buf );
    if( bytes_read == 0 )
      break;

    bytes_total += bytes_read;
    _=try writer.write( buf[0..bytes_read] );
    const f = q.chunk_fn;
    if( f ) |func| func( buf[0..bytes_read], q.chunk_data );
    z.Thread.yield() catch {};
  }

  const slice = try a.alloc( u8, bytes_total );
  @memcpy( slice[0..bytes_total], full_str.items[0..bytes_total] );
  ret.body = slice;
}

fn receiveChunkedWithDataAsync( t: type, ret: *Result, req: *ClientRequest, q: ParamsWithDataAsync(t), a: Allocator ) !void {
  ret.status = req.response.status;

  var full_str = z.ArrayList( u8 ).init( a );
  defer full_str.deinit();
  const writer = full_str.writer();

  var buf = try a.alloc( u8, 1024 * 16 );
  defer a.free( buf );

  var bytes_total: usize = 0;
  const reader = req.reader();

  //todo: throw this into another thread
  while( true ) {
    const bytes_read = try reader.read( buf );
    if( bytes_read == 0 )
      break;

    bytes_total += bytes_read;
    _=try writer.write( buf[0..bytes_read] );
    const f = q.chunk_fn;
    if( f ) |func| func( buf[0..bytes_read], q.chunk_data );
    z.Thread.yield() catch {};
  }

  const slice = try a.alloc( u8, bytes_total );
  @memcpy( slice[0..bytes_total], full_str.items[0..bytes_total] );
  ret.body = slice;
}