better hover

lua/hover.lua

@@ -0,0 +1,182 @@
+-- Cycling hover: K shows line diagnostics one at a time, then the LSP hover.
+-- Repeated K cycles through them; <CR> enters the floating window.
+local M = {}
+
+M.win = nil   -- floating window handle
+M.buf = nil   -- floating buffer handle
+M.items = nil -- list of render functions for the current cycle
+M.idx = 0     -- current position in the cycle
+M.bufnr = nil -- source buffer the cycle was started from
+M.lnum = nil  -- 0-indexed source line
+M.col = nil   -- 0-indexed source column
+
+local group = vim.api.nvim_create_augroup("HoverCycle", { clear = true })
+
+local SEVERITY = { "ERROR", "WARN", "INFO", "HINT" }
+
+local function float_open()
+    return M.win ~= nil and vim.api.nvim_win_is_valid(M.win)
+end
+
+local function close_float()
+    if float_open() then
+        vim.api.nvim_win_close(M.win, true)
+    end
+    M.win = nil
+    M.buf = nil
+end
+
+-- Open (or replace) the float with the given lines.
+local function open_float(lines, ft)
+    close_float()
+
+    local buf = vim.api.nvim_create_buf(false, true)
+    vim.api.nvim_buf_set_lines(buf, 0, -1, false, lines)
+    vim.bo[buf].bufhidden = "wipe"
+
+    local width = 1
+    for _, l in ipairs(lines) do
+        width = math.max(width, vim.fn.strdisplaywidth(l))
+    end
+    width = math.min(width, math.floor(vim.o.columns * 0.8))
+    local height = math.min(math.max(#lines, 1), math.floor(vim.o.lines * 0.6))
+
+    local win = vim.api.nvim_open_win(buf, false, {
+        relative = "cursor",
+        row = 1,
+        col = 0,
+        width = width,
+        height = height,
+        style = "minimal",
+        border = "rounded",
+        focusable = true,
+    })
+    vim.wo[win].wrap = true
+    vim.wo[win].conceallevel = 2
+    vim.wo[win].concealcursor = "nc"
+
+    M.win = win
+    M.buf = buf
+
+    -- Set filetype only now that the buffer is shown in a window, so the
+    -- FileType autocmds (treesitter + render-markdown) render into it.
+    if ft then vim.bo[buf].filetype = ft end
+    vim.bo[buf].modifiable = false
+
+    -- Close when the cursor moves in the source buffer. Switching INTO the
+    -- float (via <CR>) does not move the source cursor, so it survives that.
+    vim.api.nvim_clear_autocmds({ group = group })
+    vim.api.nvim_create_autocmd({ "CursorMoved", "CursorMovedI", "InsertEnter" }, {
+        group = group,
+        buffer = M.bufnr,
+        callback = function() close_float() end,
+    })
+
+    vim.keymap.set("n", "q", close_float, { buffer = buf, nowait = true, silent = true })
+end
+
+local function with_header(header, body, ft)
+    local lines = {}
+    if header then
+        lines[1] = header
+        lines[2] = ""
+    end
+    vim.list_extend(lines, body)
+    open_float(lines, ft)
+end
+
+local function show_lsp_hover(idx, n)
+    local header = n > 1 and ("Hover [%d/%d]"):format(idx, n) or nil
+
+    local clients = vim.lsp.get_clients({ bufnr = M.bufnr, method = "textDocument/hover" })
+    if #clients == 0 then
+        with_header(header, { "No LSP hover available" })
+        return
+    end
+
+    local params = vim.lsp.util.make_position_params(0, clients[1].offset_encoding)
+    vim.lsp.buf_request(M.bufnr, "textDocument/hover", params, function(_, result)
+        if M.idx ~= idx or M.bufnr ~= vim.api.nvim_get_current_buf() then
+            return -- cycle moved on before the response arrived
+        end
+        local body = {}
+        if result and result.contents then
+            body = vim.lsp.util.convert_input_to_markdown_lines(result.contents)
+        end
+        if vim.tbl_isempty(body) then body = { "No hover information" } end
+
+        with_header(header, body, "markdown")
+    end)
+end
+
+-- True if the diagnostic's range covers the (lnum, col) cursor position.
+local function under_cursor(d, lnum, col)
+    local end_lnum = d.end_lnum or d.lnum
+    local end_col = d.end_col or (d.col + 1)
+    if lnum < d.lnum or lnum > end_lnum then return false end
+    if lnum == d.lnum and col < d.col then return false end
+    if lnum == end_lnum and col >= math.max(end_col, d.col + 1) then return false end
+    return true
+end
+
+-- Diagnostics whose range is under the cursor, sorted by start column.
+local function cursor_diags()
+    local diags = vim.tbl_filter(
+        function(d) return under_cursor(d, M.lnum, M.col) end,
+        vim.diagnostic.get(M.bufnr, { lnum = M.lnum }))
+    table.sort(diags, function(a, b) return a.col < b.col end)
+    return diags
+end
+
+local function build_items()
+    local items = {}
+    local diags = cursor_diags()
+
+    for _, d in ipairs(diags) do
+        items[#items + 1] = function(idx, n)
+            local sev = SEVERITY[d.severity] or "DIAG"
+            local header = n > 1 and ("Diagnostic [%d/%d] %s"):format(idx, n, sev)
+                or ("Diagnostic %s"):format(sev)
+            with_header(header, vim.split(d.message, "\n", { plain = true }))
+        end
+    end
+
+    items[#items + 1] = show_lsp_hover
+    return items
+end
+
+local function show()
+    M.items[M.idx](M.idx, #M.items)
+end
+
+-- Mapped to K.
+function M.hover()
+    if float_open() then
+        M.idx = M.idx % #M.items + 1
+        show()
+        return
+    end
+
+    M.bufnr = vim.api.nvim_get_current_buf()
+    local pos = vim.api.nvim_win_get_cursor(0)
+    M.lnum = pos[1] - 1
+    M.col = pos[2]
+
+    -- No diagnostic under cursor -> a single LSP-hover item (no cycle header),
+    -- still rendered in our managed float so <CR> can enter it.
+    M.items = build_items()
+    M.idx = 1
+    show()
+end
+
+-- Mapped to <CR>: focus the float if open, otherwise default <CR>.
+function M.enter()
+    if float_open() then
+        vim.api.nvim_set_current_win(M.win)
+    else
+        vim.api.nvim_feedkeys(
+            vim.api.nvim_replace_termcodes("<CR>", true, false, true), "n", false)
+    end
+end
+
+return M