# `Choreo.Render.Mermaid`
[🔗](https://github.com/code-shoily/choreo/blob/v0.14.1/lib/choreo/render/mermaid.ex#L1)

Mermaid.js rendering for `Choreo` architecture diagrams.

This module translates a `Choreo` struct into Mermaid syntax. The default
output is a flowchart, but the native `architecture-beta` diagram type is
also supported via the `:syntax` option.

## Node shapes

Infrastructure types map to Mermaid flowchart shapes:

| Type            | Mermaid shape   | Syntax                    |
| --------------- | --------------- | ------------------------- |
| `database`      | `:cylinder`     | `[(label)]`               |
| `cache`         | `:hexagon`      | `{{label}}`               |
| `service`       | `:subroutine`   | `[[label]]`               |
| `network`       | `:rounded_rect` | `[label]`                 |
| `user`          | `:circle`       | `((label))`               |
| `load_balancer` | `:hexagon`      | `{{label}}`               |
| `queue`         | `:stadium`      | `([label])`               |
| `storage`       | `:rounded_rect` | `[label]`                 |
| `generic`       | `:rounded_rect` | `[label]`                 |

Edges are styled according to their semantic type (`:connection` or
`:dataflow`). Dataflow edges use a dashed purple stroke; virtual
edges (from transitive filtering) use a light-grey stroke.

## Themes

All built-in themes (`:default`, `:dark`, `:minimal`, `:warm`, `:forest`,
`:ocean`) are supported. Per-type colours and shapes are resolved from
`Choreo.Theme` and translated into Mermaid `style` declarations.

## Examples

    mermaid = Choreo.Render.Mermaid.to_mermaid(system)
    mermaid = Choreo.Render.Mermaid.to_mermaid(system, theme: :dark)

    theme = Choreo.Theme.custom(colors: [database: "#ff0000"])
    mermaid = Choreo.Render.Mermaid.to_mermaid(system, theme: theme)

The output can be wrapped in a Markdown code block:

````markdown
```mermaid
<%= mermaid %>
```
````

# `theme`

```elixir
@spec theme(atom(), keyword()) :: map()
```

Returns a theme for `Choreo` infrastructure Mermaid diagrams.

See also `Choreo.theme/2`.

# `to_mermaid`

```elixir
@spec to_mermaid(Choreo.t(), keyword()) :: String.t()
```

Renders a `Choreo` struct to a Mermaid string.

## Options

  * `:syntax` - `:flowchart` (default) or `:architecture` (native
    `architecture-beta` diagram type)
  * `:theme` - `:default`, `:dark`, `:minimal`, `:warm`, `:forest`, `:ocean`
    or a `Choreo.Theme` struct (only applies to `:flowchart`)
  * `:direction` - `:td` (default), `:lr`, `:bt`, `:rl` (only applies to
    `:flowchart`)
  * `:highlighted_nodes` - list of node IDs to highlight (only applies to
    `:flowchart`)
  * `:highlighted_edges` - list of edge IDs or `{from, to}` tuples to
    highlight (only applies to `:flowchart`)
  * Any other option accepted by `Yog.Multi.Mermaid.to_mermaid/2`

## Examples

    iex> system = Choreo.new() |> Choreo.add_service(:api)
    iex> mermaid = Choreo.Render.Mermaid.to_mermaid(system)
    iex> String.contains?(mermaid, "graph TD")
    true
    iex> String.contains?(mermaid, "api")
    true

---

*Consult [api-reference.md](api-reference.md) for complete listing*