Add "vibe-coded" go-helper utils

lua/scripts/go-extract-interface.lua

@@ -0,0 +1,137 @@
+local M = {}
+
+-- Parse method signature from a line
+local function parse_method(line)
+    -- Match: func (receiver) MethodName(params) (returns)
+    local pattern = "^func%s+%([^)]+%)%s+([%w_]+)%s*(%b())%s*(.*)"
+    local name, params, returns = line:match(pattern)
+
+    if name then
+        -- Clean up returns (remove leading spaces and parentheses if single return)
+        returns = returns:gsub("^%s+", "")
+        if returns:match("^%b()") then
+            returns = " " .. returns
+        elseif returns ~= "" then
+            returns = " " .. returns
+        end
+
+        return name .. params .. returns
+    end
+    return nil
+end
+
+-- Find all methods for a given struct type
+local function find_struct_methods(struct_name, bufnr)
+    local methods = {}
+    local lines = vim.api.nvim_buf_get_lines(bufnr, 0, -1, false)
+
+    -- Pattern to match methods with the struct as receiver
+    -- Matches both pointer and value receivers
+    local patterns = {
+        "^func%s+%(%s*%w+%s+%*?" .. struct_name .. "%s*%)", -- Standard pattern
+    }
+
+    for i, line in ipairs(lines) do
+        for _, pattern in ipairs(patterns) do
+            if line:match(pattern) then
+                local method_sig = parse_method(line)
+                if method_sig then
+                    table.insert(methods, method_sig)
+                end
+            end
+        end
+    end
+
+    return methods
+end
+
+-- Get struct name under cursor
+local function get_struct_name()
+    local line = vim.api.nvim_get_current_line()
+
+    -- Try to match: type StructName struct
+    local struct_name = line:match("^type%s+([%w_]+)%s+struct")
+
+    if not struct_name then
+        -- Try to match if cursor is on struct keyword
+        struct_name = line:match("type%s+([%w_]+)%s+struct")
+    end
+
+    return struct_name
+end
+
+-- Generate interface from methods
+local function generate_interface(struct_name, methods)
+    if #methods == 0 then
+        return nil, "No methods found for struct " .. struct_name
+    end
+
+    -- Create interface name (conventionally, I + StructName or StructName + er)
+    local interface_name = "I" .. struct_name
+
+    local lines = {
+        "type " .. interface_name .. " interface {",
+    }
+
+    for _, method in ipairs(methods) do
+        local method_without_bracket = method:gsub("{$", "")
+        local cleaned_method = method_without_bracket:gsub("%s+$", "")
+        table.insert(lines, "\t" .. cleaned_method)
+    end
+
+    table.insert(lines, "}")
+
+    return lines, nil
+end
+
+-- Main function to extract interface
+function M.extract_interface()
+    local bufnr = vim.api.nvim_get_current_buf()
+
+    -- Check if we're in a Go file
+    local filetype = vim.bo[bufnr].filetype
+    if filetype ~= "go" then
+        vim.notify("This command only works in Go files", vim.log.levels.ERROR)
+        return
+    end
+
+    -- Get struct name under cursor
+    local struct_name = get_struct_name()
+    if not struct_name then
+        vim.notify("Cursor is not on a struct definition", vim.log.levels.ERROR)
+        return
+    end
+
+    -- Find all methods for this struct
+    local methods = find_struct_methods(struct_name, bufnr)
+
+    -- Generate interface
+    local interface_lines, err = generate_interface(struct_name, methods)
+    if err then
+        vim.notify(err, vim.log.levels.WARN)
+        return
+    end
+
+    -- Insert interface above the struct definition
+    local cursor_line = vim.api.nvim_win_get_cursor(0)[1]
+    vim.api.nvim_buf_set_lines(bufnr, cursor_line - 1, cursor_line - 1, false, interface_lines)
+    vim.api.nvim_buf_set_lines(bufnr, cursor_line, cursor_line, false, { "" }) -- Empty line
+
+    vim.notify("Interface extracted: " .. #methods .. " methods found", vim.log.levels.INFO)
+end
+
+-- Setup function for lazy.nvim
+function M.setup()
+    -- Create command
+    vim.api.nvim_create_user_command("GoExtractInterface", M.extract_interface, {
+        desc = "Extract interface from Go struct under cursor",
+    })
+
+    -- Optional: Add keybinding
+    vim.keymap.set("n", "<leader>cei", M.extract_interface, {
+        desc = "Extract interface from struct",
+        silent = true,
+    })
+end
+
+return M