Adds graph editing

Project.toml

@@ -10,6 +10,8 @@ DataAPI = "9a962f9c-6df0-11e9-0e5d-c546b8b5ee8a"
 DataFrames = "a93c6f00-e57d-5684-b7b6-d8193f3e46c0"
 Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"
 FLoops = "cc61a311-1640-44b5-9fba-1b764f453329"
+InteractiveUtils = "b77e0a4c-d291-57a0-90e8-8db25a27a240"
+JSON = "682c06a0-de6a-54ab-a142-c8b1cf79cde6"
 Markdown = "d6f4376e-aef5-505a-96c1-9c027394607a"
 MultiScaleTreeGraph = "dd4a991b-8a45-4075-bede-262ee62d5583"
 PlantMeteo = "4630fe09-e0fb-4da5-a846-781cb73437b6"
@@ -18,13 +20,22 @@ Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 Tables = "bd369af6-aec1-5ad0-b16a-f7cc5008161c"
 Term = "22787eb5-b846-44ae-b979-8e399b8463ab"
 
+[weakdeps]
+HTTP = "cd3eb016-35fb-5094-929b-558a96fad6f3"
+
+[extensions]
+PlantSimEngineGraphEditorExt = "HTTP"
+
 [compat]
 AbstractTrees = "0.4"
 CSV = "0.10"
 DataAPI = "1.15"
 DataFrames = "1"
 Dates = "1.10"
 FLoops = "0.2"
+HTTP = "1"
+InteractiveUtils = "1.10"
+JSON = "1"
 Markdown = "1.10"
 MultiScaleTreeGraph = "0.15.1"
 PlantMeteo = "0.8.2"

docs/make.jl

@@ -34,6 +34,7 @@ makedocs(;
             "Detailed first simulation" => "./step_by_step/detailed_first_example.md",
             "Coupling" => "./step_by_step/simple_model_coupling.md",
             "Model Switching" => "./step_by_step/model_switching.md",
+            "Graph visualization and editing" => "./step_by_step/graph_visualization_editor.md",
             "Quick examples" => "./step_by_step/quick_and_dirty_examples.md",
             "Implementing a process" => "./step_by_step/implement_a_process.md",
             "Implementing a model" => "./step_by_step/implement_a_model.md",

docs/src/step_by_step/graph_visualization_editor.md

@@ -0,0 +1,86 @@
+# Graph visualization and editing
+
+`PlantSimEngine` can export a dependency graph view from a [`ModelMapping`](@ref). The static viewer is available from the core package and does not require any web server dependency.
+
+```julia
+using PlantSimEngine
+using PlantSimEngine.Examples
+
+mapping = ModelMapping(
+    ToyLAIModel(),
+    Beer(0.5);
+    status=(TT_cu=1.0:200.0,),
+)
+
+write_graph_view("dependency_graph.html", mapping)
+```
+
+The same serialization path is used by the interactive editor. The editor is implemented as a Julia package extension, so the HTTP/WebSocket stack is loaded only when [`HTTP.jl`](https://github.com/JuliaWeb/HTTP.jl) is available and loaded in the active session.
+
+```julia
+using PlantSimEngine
+using PlantSimEngine.Examples
+using HTTP
+
+mapping = ModelMapping(
+    ToyLAIModel(),
+    Beer(0.5);
+    status=(TT_cu=1.0:200.0,),
+)
+
+session = edit_graph(mapping)
+session.url
+session
+```
+
+To start from a blank graph and build a mapping from scratch, omit the mapping:
+
+```julia
+session = edit_graph()
+```
+
+By default, `edit_graph` opens `session.url` in the system default browser. Pass `open_browser=false` to keep the session headless, for example in scripts or tests:
+
+```julia
+session = edit_graph(mapping; open_browser=false)
+```
+
+The browser sends edit commands to Julia over a WebSocket. Julia remains the source of truth: it applies the edit, rebuilds the [`ModelMapping`](@ref), recompiles graph diagnostics, and sends the updated graph back to the browser.
+
+To stop the HTTP/WebSocket session, run:
+
+```julia
+close(session)
+```
+
+Use [`current_mapping`](@ref) to recover the latest mapping from the session:
+
+```julia
+edited_mapping = current_mapping(session)
+close(session)
+```
+
+The web editor also exposes a dedicated "Mapping code" panel. It shows the current [`ModelMapping`](@ref) as Julia code, and can write that code to a `.jl` file so it can be copied/pasted or reused in scripts. The generated file is intentionally plain Julia: it imports the packages needed by the selected models and defines a top-level `mapping` variable:
+
+```julia
+using PlantSimEngine
+using PlantSimEngine.Examples
+
+mapping = ModelMapping(
+    # ...
+)
+```
+
+After writing a file once, every successful edit, undo, redo, or recent-file load automatically rewrites that same file. The session also keeps a recovery autosave in the temporary directory. The top-left "Open" button can reopen a mapping script from a file path or from the recent mapping list. Use git or another version-control system for mapping scripts that matter for a simulation workflow.
+
+The editor extension currently supports the same edit operations as the Julia API:
+
+- add, remove, and replace a model at a scale;
+- update an existing model's parameter values, scale, or rate from the inspector;
+- keep the model default rate, or set a custom `ClockSpec(dt, phase)` when adding a model;
+- set a mapped input variable, either from the inspector or by drawing a connection from an output port to an input port;
+- map a scalar source value or a vector of values from one or several source scales;
+- mark or unmark a variable as [`PreviousTimeStep`](@ref);
+- undo and redo edits inside the live session.
+
+If `HTTP` is not loaded, `edit_graph(mapping)` throws an error explaining that the interactive editor requires `using HTTP`. Static graph visualization through [`write_graph_view`](@ref), `graph_view`, and [`graph_view_json`](@ref) remains available without loading `HTTP`.