feat(molten-nvim): enhance molten config and add custom init function and statusline

lua/astrocommunity/code-runner/molten-nvim/README.md

@@ -24,3 +24,12 @@ A neovim plugin for interactively running code with the jupyter kernel. Fork of
 > For up to date docs, visit the repository.
 
 **Repository:** <https://github.com/benlubas/molten-nvim>
+
+## Customizations
+
+This plugin config adds a custom init function for Python venvs. When calling `<Leader>mmp`, we check if a venv is activated. If it is, we check if a jupyter kernel spec for this venv already exists and `:MoltenInit` this kernel spec. If no kernel spec is found, we prompt for a unique name, create the kernel spec and `:MoltenInit` it.
+
+It also adds a status line indication if molten is activated and what kernel is initialized.
+
+> [!TIP]
+> When using a global molten venv as described in the repository, we need to set the variable `python3_host_prog` to the Python executable there, which in AstroNVim is done in `AstroCore` in the `options.g` table, for example: `python3_host_prog = vim.fn.expand "~/.virtualenvs/neovim/bin/python3"`.

lua/astrocommunity/code-runner/molten-nvim/init.lua

@@ -1,20 +1,132 @@
+local function ensure_kernel_for_venv()
+  local venv_path = os.getenv "VIRTUAL_ENV" or os.getenv "CONDA_PREFIX"
+  if not venv_path then
+    vim.notify("No virtual environment found.", vim.log.levels.WARN)
+    return
+  end
+
+  -- Canonicalize the venv_path to ensure consistency
+  venv_path = vim.fn.fnamemodify(venv_path, ":p")
+
+  -- Check if the kernel spec already exists
+  local handle = io.popen "jupyter kernelspec list --json"
+  local existing_kernels = {}
+  if handle then
+    local result = handle:read "*a"
+    handle:close()
+    local json = vim.fn.json_decode(result)
+    -- Iterate over available kernel specs to find the one for this virtual environment
+    for kernel_name, data in pairs(json.kernelspecs) do
+      existing_kernels[kernel_name] = true -- Store existing kernel names for validation
+      local kernel_path = vim.fn.fnamemodify(data.spec.argv[1], ":p") -- Canonicalize the kernel path
+      if kernel_path:find(venv_path, 1, true) then
+        vim.notify("Kernel spec for this virtual environment already exists.", vim.log.levels.INFO)
+        return kernel_name
+      end
+    end
+  end
+
+  -- Prompt the user for a custom kernel name, ensuring it is unique
+  local new_kernel_name
+  repeat
+    new_kernel_name = vim.fn.input "Enter a unique name for the new kernel spec: "
+    if new_kernel_name == "" then
+      vim.notify("Please provide a valid kernel name.", vim.log.levels.ERROR)
+      return
+    elseif existing_kernels[new_kernel_name] then
+      vim.notify(
+        "Kernel name '" .. new_kernel_name .. "' already exists. Please choose another name.",
+        vim.log.levels.WARN
+      )
+      new_kernel_name = nil
+    end
+  until new_kernel_name
+
+  -- Create the kernel spec with the unique name
+  print "Creating a new kernel spec for this virtual environment..."
+  local cmd = string.format(
+    '%s -m ipykernel install --user --name="%s"',
+    vim.fn.shellescape(venv_path .. "/bin/python"),
+    new_kernel_name
+  )
+
+  os.execute(cmd)
+  vim.notify("Kernel spec '" .. new_kernel_name .. "' created successfully.", vim.log.levels.INFO)
+  return new_kernel_name
+end
+
 ---@type LazySpec
 return {
   "benlubas/molten-nvim",
   lazy = false,
   version = "^1", -- use version <2.0.0 to avoid breaking changes
   build = ":UpdateRemotePlugins",
   dependencies = {
-    "AstroNvim/astrocore",
-    opts = function(_, opts)
-      if not opts.mappings then opts.mappings = {} end
-      local prefix = "<leader>m"
-
-      opts.mappings.n[prefix .. "mi"] = { "<Cmd>MoltenInit<CR>", desc = "Initialize the plugin" }
-      opts.mappings.n[prefix .. "e"] = { "<Cmd>MoltenEvaluateOperator<CR>", desc = "Run operator selection" }
-      opts.mappings.n[prefix .. "rl"] = { "<Cmd>MoltenEvaluateLine<CR>", desc = "Evaluate line" }
-      opts.mappings.n[prefix .. "rr"] = { "<Cmd>MoltenReevaluateCell<CR>", desc = "Re-evaluate cell" }
-      opts.mappings.v[prefix .. "r"] = { ":<C-u>MoltenEvaluateVisual<CR>gv", desc = "Evaluate visual selection" }
-    end,
+    { "AstroNvim/astroui", opts = { icons = { Molten = "󱓞" } } },
+    {
+      "AstroNvim/astrocore",
+      opts = function(_, opts)
+        if not opts.mappings then opts.mappings = {} end
+        local prefix = "<leader>m"
+
+        opts.mappings.n[prefix] = { desc = require("astroui").get_icon("Molten", 1, true) .. "Molten" }
+        opts.mappings.n[prefix .. "e"] = { "<Cmd>MoltenEvaluateOperator<CR>", desc = "Run operator selection" }
+        opts.mappings.n[prefix .. "l"] = { "<Cmd>MoltenEvaluateLine<CR>", desc = "Evaluate line" }
+        opts.mappings.n[prefix .. "c"] = { "<Cmd>MoltenReevaluateCell<CR>", desc = "Re-evaluate cell" }
+
+        opts.mappings.n[prefix .. "m"] = { desc = "Commands" }
+        opts.mappings.n[prefix .. "mi"] = { "<Cmd>MoltenInit<CR>", desc = "Initialize the plugin" }
+        opts.mappings.n[prefix .. "mh"] = { "<Cmd>MoltenHideOutput<CR>", desc = "Hide Output" }
+        opts.mappings.n[prefix .. "mI"] = { "<Cmd>MoltenInterrupt<CR>", desc = "Interrupt Kernel" }
+        opts.mappings.n[prefix .. "mR"] = { "<Cmd>MoltenRestart<CR>", desc = "Restart Kernel" }
+        -- Dynamic Kernel Initialization based on Python Virtual Environment
+        opts.mappings.n[prefix .. "mp"] = {
+          function()
+            local kernel_name = ensure_kernel_for_venv()
+            if kernel_name then
+              vim.cmd(("MoltenInit %s"):format(kernel_name))
+            else
+              vim.notify("No kernel to initialize.", vim.log.levels.WARN)
+            end
+          end,
+          desc = "Initialize for Python venv",
+          silent = true,
+        }
+
+        opts.mappings.v[prefix] = { desc = require("astroui").get_icon("Molten", 1, true) .. "Molten" }
+        opts.mappings.v[prefix .. "r"] = { ":<C-u>MoltenEvaluateVisual<CR>gv", desc = "Evaluate visual selection" }
+
+        opts.mappings.n["]c"] = { "<Cmd>MoltenNext<CR>", desc = "Next Molten Cel" }
+        opts.mappings.n["[c"] = { "<Cmd>MoltenPrev<CR>", desc = "Previous Molten Cell" }
+      end,
+    },
+    {
+      -- Configure heirline.nvim to add the Molten status component
+      "rebelot/heirline.nvim",
+      opts = function(_, opts)
+        local utils = require "heirline.utils"
+        local molten_component = {
+          provider = function()
+            -- Display the status of Molten and attached kernels
+            local init_status = require("molten.status").initialized()
+            local kernel_status = require("molten.status").kernels()
+            local info = (init_status ~= "" and init_status .. ": ") .. kernel_status
+            return info ~= "" and info or ""
+          end,
+          condition = function() return require("molten.status").initialized() ~= "" end,
+          padding = { left = 1, right = 1 },
+          hl = function()
+            local theme_hl = utils.get_highlight "@comment.note"
+            return {
+              bg = theme_hl.bg,
+              fg = theme_hl.fg,
+            }
+          end,
+        }
+        local spacer = { provider = " " }
+        table.insert(opts.statusline, #opts.statusline, spacer)
+        table.insert(opts.statusline, #opts.statusline, molten_component)
+      end,
+    },
   },
 }