Mdthbs

I know this is a shit question, but I don't know what to do because I don't have much time left.

I need a diagram like this for my thesis:

I already tried making this with tikz. First I tried it with the libraries shapes and arrows on my own with node and path, but I couldn't do it.
Then I tried it with the trees library, but it also didn't work out how I wanted.
Now I need you help. I guess it's just a few lines of code.

Here is the code of my best attempt so far

documentclass[a4,border=10pt]{article}

 usepackage{tikz}

 usetikzlibrary{shapes,arrows}



 begin{document}

 % Define block styles

 tikzstyle{decision} = [diamond, draw, fill=blue!20, 

    text width=4.5em, text badly centered, node distance=3cm, inner sep=0pt]

 tikzstyle{block} = [rectangle, draw, fill=blue!20, 

    text width=5em, text centered, minimum height=4em]

 tikzstyle{line} = [draw, -latex']



 begin{tikzpicture}[node distance = 2cm, auto]

    % Place nodes

    node [decision] (outsideThreat) {Bedrohung von außen?};

    node [block, left of=outsideThreat, below of=outsideThreat] (firewall)  {Firewall};

    node [decision, right of=outsideThreat, below of=outsideThreat] (knownThreat)  {Bedrohung bekannt?};

    node [block, below of=knownThreat, left of=knownThreat] (idsAds) {IDS/ADS};

    node [block, below of=knownThreat, right of=knownThreat] (honeypots)  {Honeypots};

     % Draw edges

    path [line] (outsideThreat) --(outsideThreat-|firewall) -- node {yes}  (firewall);

     path [line] (outsideThreat) --(knownThreat|-outsideThreat) -- node {no}  (knownThreat);

    path [line] (firewall) -- (knownThreat);

    path [line] (knownThreat) --(knownThreat-|idsAds) -- node {yes} (idsAds);  

    path [line] (knownThreat) --(honeypots|-knownThreat) -- node {no} (honeypots);

 end{tikzpicture}

 end{document}

This code produces this output:

I can't manage to get the Firewall block and the Bedrohung bekannt? decision on the same level horizontally. And don't know how to achieve the exact arrows of my example above.

Here is one way!

documentclass[tikz,border=3mm]{standalone}

usetikzlibrary{shapes.geometric} 

begin{document}

begin{tikzpicture}[thick,>=stealth]

tikzset{box/.style=

   {draw,minimum height=1.2cm,minimum width=3cm}}

path 

(0,2) node[diamond,draw] (d1) {decision1}

(-5,-2) node[box] (b1) {block1}

(4,-2) node[diamond,draw] (d2) {decision2}

++(-90:1.5) coordinate (d2s) {}

+(4,-2) node[box] (b3) {block3}

+(-3,-1.5) node[box] (b4) {block4};

draw (0,0)--(d1);

draw[->] (0,0)-|(d2) node[pos=.25,above]{no};

draw[->] (0,0)-|(b1) node[pos=.25,above]{yes};

draw[->] (b1)--(d2) node[midway,above]{some condition};

draw (d2)--(d2s);

draw[->] (d2s)-|(b3) node[pos=.25,above]{no};

draw[->] (d2s)-|(b4) node[pos=.25,above]{yes};

end{tikzpicture}

end{document}

With forest you can automatize several things. In particular, you can leave the decision whether or not a node is a decision to forest.

documentclass[tikz,border=3.14mm]{standalone}

usepackage[edges]{forest}

usetikzlibrary{shapes.geometric}

begin{document}

begin{forest}

forked edges,

for tree={l sep=3em,s sep=3em,edge={-stealth},

 where n children=2{diamond}{rectangle,inner sep=1ex},draw,

 if n=1{edge label={node [pos=0.25, below] {yes} } }{edge label={node [pos=0.25, below] {no} } }}

[decision 1

 [block 1,alias=b1]

 [decision 2,alias=d2

  [block 2]

  [block 3]

 ]

]

draw[-stealth] (b1) -- (d2) node[midway,above]{pft};

end{forest}

end{document}

For fun, a simple pstricks code:

documentclass[border=6pt]{standalone}%

usepackage[utf8]{inputenc}

usepackage[T1]{fontenc}

usepackage{pst-node}

newcommand{psstrut}{rule[-0.55cm]{0pt}{1.25cm}}

newcommand{diastrut}{rule[-0.65cm]{0pt}{1.45cm}}%



begin{document}



{sffamilyeverymath{displaystyle}%

psset{framesep=1pt, arrows=->, arrowinset=0.1,linejoin=1}

begin{psmatrix}[rowsep=2.5cm, colsep=2cm, emnode=r]% 

%%% Nodes

& dianode[framesep = -2pt]{d1}{{diastrut Decision 1}}\

[name=b1] psframebox{makebox[2.5cm]{psstrut block 1}} & & dianode[framesep = -2pt]{d2}{{diastrut Decision 2}}\

 & [name=b2] psframebox{makebox[2.5cm]{psstrut block 2}} & & [name=b3] psframebox{makebox[2.5cm]{psstrut block 3}}

 %%% Node connections

 psset{angleA=-90, angleB=90, armA=0.8cm, armB=0.8cm, labelsep=2pt}

 ncangles{d1}{b1}nbput{yes}

 ncangles{d1}{d2}naput{no}

 ncline{b1}{d2}naput{some condition}

 ncangles{d2}{b2}nbput{yes}

 ncangles{d2}{b3}naput{no}

 end{psmatrix}}



end{document}