-- Go LSP configuration
-- Uses gopls installed via Mason

local capabilities = require("cmp_nvim_lsp").default_capabilities(vim.lsp.protocol.make_client_capabilities())

vim.lsp.config("gopls", {
    cmd = { "gopls" },
    filetypes = { "go", "gomod", "gowork", "gotmpl" },
    capabilities = capabilities,
    root_markers = { "go.mod", ".git" },
    settings = {
        gopls = {
            hints = {
                assignVariableTypes = true,
                compositeLiteralFields = true,
                compositeLiteralTypes = true,
                constantValues = true,
                functionTypeParameters = true,
                parameterNames = true,
                rangeVariableTypes = true,
            },
            analyses = {
                unusedparams = true,
                shadow = true,
                nilness = true,
            },
            staticcheck = true,
            gofumpt = true, -- prefer gofumpt formatting
            usePlaceholders = true,
            completeUnimported = true,
        },
    },
})

-- Go-specific LSP attach handlers
vim.api.nvim_create_autocmd("LspAttach", {
    callback = function(args)
        local client = vim.lsp.get_client_by_id(args.data.client_id)
        if client and client.name == "gopls" then
            local bufnr = args.buf

            -- Go: organize imports on demand
            vim.keymap.set("n", "<leader>gi", function()
                vim.lsp.buf.code_action({
                    context = { only = { "source.organizeImports" } },
                    apply = true,
                })
            end, { buffer = bufnr, desc = "Go: Organize imports" })

            -- Go: toggle test file
            vim.keymap.set("n", "<leader>gt", function()
                local fname = vim.fn.expand("%")
                if fname:match("_test%.go$") then
                    vim.cmd("edit " .. fname:gsub("_test%.go$", ".go"))
                else
                    vim.cmd("edit " .. fname:gsub("%.go$", "_test.go"))
                end
            end, { buffer = bufnr, desc = "Go: Toggle test file" })

            -- Go: run current file's tests
            vim.keymap.set("n", "<leader>gr", function()
                vim.cmd("!go test ./...")
            end, { buffer = bufnr, desc = "Go: Run tests" })
        end
    end,
})

vim.lsp.enable("gopls")