#set text(lang: "sl")
#set page("a4", margin: 5mm)
#import "@preview/fletcher:0.5.8" as fletcher: diagram, node, edge
#import fletcher.shapes: house, chevron, pill, hexagon

#let commit-color = green
#let tag-color = orange
#let branch-color = purple
#let thin = 0.5pt;
#let thindotted = (thickness: thin, dash: "dotted");
#let thindashed = (thickness: thin, dash: "dashed");
#let commit-node(coord, hash, ..args) = node(coord, raw(hash), shape: pill, fill: commit-color.lighten(50%), stroke: thin, ..args)
#let commit-object(coord, hash, name, ..args) = node(coord, align(left, [#text(size: 8pt, gray.darken(50%), raw(hash))\ #name]), corner-radius: 7pt, fill: commit-color.lighten(50%), stroke: none, ..args)
#let tree-object(coord, hash, ..args) = commit-object(coord, hash, [tree], width: 2cm, fill: blue.lighten(50%), ..args)
#let file-object(coord, hash, name, ..args) = commit-object(coord, hash, name, width: 2cm, fill: gray.lighten(50%), ..args)

#diagram(debug: 1, node-stroke: 2pt, edge-stroke: 1pt,
    {
        let store = (0.6, 6.7)
        let (co1, co2) = {
            let x = 0.2
            let y = store.at(1)
            ((x, y+0.5), (x, y+1))
        }
        let (tree1, tree2) = {
            let x = 1.2
            ((x, co1.at(1)), (x, co2.at(1)))
        }
        let (f1, f2, f3) = { 
            let x = 2.2;
            let y = store.at(1)
            ((x, y), (x, y + 0.5), (x, y + 1))
        }
        let (A, B, C, D, E, F, G) = ((2, 6), (2, 5), (2, 4), (2, 3), (2, 2), (2, 1), (2, 0))
        let (B1, B2) = ((3, 4.5), (3, 3.5))
        let (E1, E2, E3) = ((3, 1.5), (3, 0.5), (3, -0.5))
        let (Br1, Br2) = ((F.at(0)-0.5, F.at(1)), (E2.at(0)-0.5, E2.at(1)))
        let (T1, T2) = ((E.at(0)-0.5, E.at(1)), (B.at(0)-0.5, B.at(1)))
        let refs = (3.5, store.at(1))
        let tags = (0.5, 3)
        let commit = (3.8, 2.5)
        let branches = (0.5, 0)
        let stage =(3.7, 0)
        let mc = (2.5, D.at(1)-0.5)
        node(store, [Content addressable object store], stroke: none, width: 4cm)
        commit-object(co1, "e264a1", [second commit])
        commit-object(co2, "16f29", [first commit], width: 2.8cm)
        tree-object(tree1, "16f29")
        tree-object(tree2, "16f29")
        file-object(f1, "16f29", [`new content`])
        file-object(f2, "16f29", [`unchanged`])
        file-object(f3, "16f29", [`first content`])
        edge(tree1, f2, [`bar.txt`], "->", label-angle: auto)
        edge(tree1, f1, [`foo.txt`], "->", label-angle: auto)
        edge(tree2, f2, [`bar.txt`], "->", label-angle: auto)
        edge(tree2, f3, [`foo.txt`], "->", label-angle: auto)
        edge(co2, tree2, "->")
        edge(co1, tree1, "->")



        node(store, stroke: thin, enclose:(co1, f3, f1))
    
        commit-node(A, "A 16f299")
        commit-node(B, "B 16f299")
        commit-node(C, "C 16f299")
        commit-node(D, "D 16f299")
        commit-node(E, "E 16f299")
        commit-node(F, "F 16f299")
        // merge commit
        node(mc, [Merge commit\ #text(size: 8pt)[commit with two parents]], stroke: thin, corner-radius: 10pt)
        // merged branch
        commit-node(B1, "B1 16f299")
        commit-node(B2, "B2 16f299")
        // unmerged branch
        commit-node(E1, "E1 16f299")
        commit-node(E2, "E2 16f299")
        commit-node(E3, "E3 16f299", fill: none, stroke: thindashed)
        // branches
        node(Br1, [main], shape: hexagon, stroke: branch-color)
        node(Br2, [hotfix], shape: hexagon, stroke: branch-color)
        // tags
        node(T1, [v-1.0], shape: chevron, stroke: tag-color)
        node(T2, [v-1.1], shape: chevron, stroke: tag-color)
        // refs
        node(refs, stroke: thin, inset:5pt,  snap: false, enclose: (refs, (refs.at(0)+1, refs.at(1)+1)), 
            align(left, [
                *References* (`.git/refs`)\ *Tags* (`.git/refs/tags`)\ `tag-1`: `8dd6d4b...`\ *Branches* (`.git/refs/heads`) \ `main`: `8dd6d4b...`\
            `feature-1`: `8dd6d4b...`\
            `hotfix`: `8dd6d4b...`
            ])
        )   
        node(branches, [#text(branch-color.darken(20%))[*BRANCH*]\ #text[reference that moves along when commiting canges]], 
        stroke: thin, corner-radius: 10pt, inset: 5pt, width: 4cm) /*,  enclose: (
            (branches.at(0)-0.5, branches.at(1)), 
            (branches.at(0)+1, branches.at(1))))*/
        node(tags, [#text(tag-color)[*TAG*]\ reference that don't move], 
        stroke: thin, corner-radius: 10pt, inset: 5pt,  width: 4cm)/*,  enclose: ((tags.at(0)-0.5, tags.at(1)), (tags.at(0)+1, tags.at(1))))*/
        node(stage, [*Staging area*\ #text(size: 8pt)[filesystem snapshot that will be commited in the next commit]], stroke: thindashed, corner-radius: 10pt, width: 3cm)
        node(commit, [
            #text(commit-color)[*COMMIT*]\ snapshot of filesystem tree in object store\
            #rect[
        ```
tree 65c47fee...
parent 16f299...
author MV <mv@ex...
committer MV <mv...

Add bar.txt
        ```]
        ], width:5cm, stroke: thin, corner-radius: 10pt)
        node((G.at(0)+0.4, G.at(1) - 0.3), [*Version history*\ 
                      #align(left, text(size: 8pt)[ 
                      _Directed Acyclic Graph (DAG)_ describes version history.
                      Commits are nodes in DAG, while an edge connect a commit with its parent.
        ])], stroke:none, width: 5cm)
        node(A, snap: false, enclose: (A, E3), stroke: thindashed, width: 3cm, fill: gray.lighten(70%))
        let ic = (A.at(0)+0.7, A.at(1)-0.2); 
        node(ic, [Initial commit], shape: pill, stroke: thin)
        edge(ic, A, stroke: thindotted)
        // history
        edge(B, A, "->")
        edge(C, B, "->")
        edge(D, C, "->")
        edge(E, D, "->")
        edge(F, E, "->")
        // merged branch
        edge(B1, B, "->", layer: 1, label: [parent of], label-angle: auto)
        edge(B2, B1, "->")
        edge(D, B2, "->")
        // unmerged branch
        edge(E1, E, "->")
        edge(E2, E1, "->")
        edge(E3, E2, "->", stroke: (dash: "dashed"))
        // refs
        edge(Br1, F)
        edge(Br2, E2)
        edge(T1, E)
        edge(T2, B)
        edge(Br1, branches, stroke: thindotted)
        edge(Br2, branches, stroke: thindotted)
        edge(T1, tags, stroke: thindotted)
        edge(T2, tags, stroke: thindotted)
        edge(commit, E, stroke: thindotted)
        edge(stage, E3, stroke: thindotted)
        edge((-0.5, A.at(1)), (-0.5, G.at(1)), "->", label: [time], label-side: left, label-angle: 90deg)
        edge(mc, D, stroke: thindotted)
    }
)