-- ===========================================================================
-- HLS pragma diagnostics for Neovim (EMBS)
-- ---------------------------------------------------------------------------
-- Runs hls_pragma_lint.py over C/C++ buffers and reports the results through
-- vim.diagnostic, so they show up exactly like clangd's errors.
--
-- No plugin manager involved: this file lives in the hlsdev nvim runtimepath
-- entry, and Neovim sources plugin/*.lua automatically.
--
-- Commands:
--   :HlsPragmaLint      re-run on the current buffer
--   :lua vim.diagnostic.reset(...)   (see :h vim.diagnostic)
-- ===========================================================================

if vim.g.loaded_hls_pragma_lint then
    return
end
vim.g.loaded_hls_pragma_lint = true

local ns = vim.api.nvim_create_namespace('hls_pragma_lint')

-- Locate hls_pragma_lint.py next to this runtimepath entry.
local plugin_dir = vim.fn.fnamemodify(debug.getinfo(1, 'S').source:sub(2), ':p:h')
local linter = vim.fn.fnamemodify(plugin_dir, ':h:h') .. '/hls_pragma_lint.py'

local function python()
    if vim.fn.executable('python3') == 1 then
        return 'python3'
    end
    return nil
end

local SEVERITY = {
    error = vim.diagnostic.severity.ERROR,
    warning = vim.diagnostic.severity.WARN,
    info = vim.diagnostic.severity.INFO,
}

local function parse(output, bufnr)
    local diags = {}
    for line in vim.gsplit(output, '\n', { plain = true }) do
        local _, l, c, sev, msg = line:match('^(.-):(%d+):(%d+): (%a+): (.*)$')
        if l then
            table.insert(diags, {
                bufnr = bufnr,
                lnum = tonumber(l) - 1,
                col = tonumber(c) - 1,
                severity = SEVERITY[sev] or vim.diagnostic.severity.INFO,
                message = msg,
                source = 'hls-pragma',
            })
        end
    end
    return diags
end

local function lint(bufnr)
    bufnr = bufnr or vim.api.nvim_get_current_buf()
    if not vim.api.nvim_buf_is_valid(bufnr) then
        return
    end
    local ft = vim.bo[bufnr].filetype
    if ft ~= 'c' and ft ~= 'cpp' then
        return
    end
    if vim.fn.filereadable(linter) ~= 1 then
        return
    end
    local py = python()
    if not py then
        return
    end
    local path = vim.api.nvim_buf_get_name(bufnr)
    if path == '' then
        return
    end

    local out = vim.fn.system({ py, linter, path })
    vim.diagnostic.set(ns, bufnr, parse(out, bufnr))
end

vim.api.nvim_create_autocmd({ 'BufWritePost', 'BufReadPost' }, {
    group = vim.api.nvim_create_augroup('HlsPragmaLint', { clear = true }),
    pattern = { '*.c', '*.cpp', '*.cc', '*.h', '*.hpp' },
    callback = function(ev)
        lint(ev.buf)
    end,
})

vim.api.nvim_create_user_command('HlsPragmaLint', function()
    lint(0)
end, { desc = 'Check #pragma HLS lines in this buffer' })