-- lsp.lua -
--
-- Source: Tony Banters
-- - <https://github.com/tonybanters/nvim/blob/master/lua/plugins/lsp.lua>
-- - <https://www.youtube.com/watch?v=46z_h4bNzjk>
--
return {
  'neovim/nvim-lspconfig',
  dependencies = {
    'williamboman/mason.nvim',
    'williamboman/mason-lspconfig.nvim',
    -- Auto-completion
    'hrsh7th/nvim-cmp',
    'hrsh7th/cmp-buffer',
    'hrsh7th/cmp-path',
    'saadparwaiz1/cmp_luasnip',
    'hrsh7th/cmp-nvim-lsp',
    'hrsh7th/cmp-nvim-lua',
    -- Snippets
    'L3MON4D3/LuaSnip',
    'rafamadriz/friendly-snippets',
  },
  -- Auto-formatter (for Lua files)
  config = function()
    local autoformat_filetypes = {
      "lua",
    }
    -- Create a keymap for vim.lsp.buf.implementation
    vim.api.nvim_create_autocmd('LspAttach', {
      callback = function(args)
        local client = vim.lsp.get_client_by_id(args.data.client_id)
        if not client then return end
        if vim.tbl_contains(autoformat_filetypes, vim.bo.filetype) then
          vim.api.nvim_create_autocmd("BufWritePre", {
            buffer = args.buf,
            callback = function()
              vim.lsp.buf.format({
                formatting_options = { tabSize = 2, insertSpaces = true },
                bufnr = args.buf,
                id = client.id
              })
            end
          })
        end
      end
    })

    -- Configure error/warnings interface
    vim.diagnostic.config({
      virtual_text = true,
      severity_sort = true,
      float = {
        style = 'minimal',
        border = 'rounded',
        header = '',
        prefix = '',
      },
      signs = {
        text = {
          [vim.diagnostic.severity.ERROR] = '✘',
          [vim.diagnostic.severity.WARN] = '▲',
          [vim.diagnostic.severity.HINT] = '⚑',
          [vim.diagnostic.severity.INFO] = '»',
        },
      },
    })

    -- Add cmp_nvim_lsp capabilities settings to lspconfig
    -- This should be executed before you configure any language server
    local lspconfig_defaults = require('lspconfig').util.default_config
    lspconfig_defaults.capabilities = vim.tbl_deep_extend(
      'force',
      lspconfig_defaults.capabilities,
      require('cmp_nvim_lsp').default_capabilities()
    )

    -- This is where you enable features that only work
    -- if there is a language server active in the file
    vim.api.nvim_create_autocmd('LspAttach', {
      callback = function(event)
        local opts = { buffer = event.buf }

        vim.keymap.set('n', 'K', '<cmd>lua vim.lsp.buf.hover()<cr>', opts)
        vim.keymap.set('n', 'gd', '<cmd>lua vim.lsp.buf.definition()<cr>', opts)
        vim.keymap.set('n', 'gD', '<cmd>lua vim.lsp.buf.declaration()<cr>', opts)
        vim.keymap.set('n', 'gi', '<cmd>lua vim.lsp.buf.implementation()<cr>', opts)
        vim.keymap.set('n', 'go', '<cmd>lua vim.lsp.buf.type_definition()<cr>', opts)
        vim.keymap.set('n', 'gr', '<cmd>lua vim.lsp.buf.references()<cr>', opts)
        vim.keymap.set('n', 'gs', '<cmd>lua vim.lsp.buf.signature_help()<cr>', opts)
        vim.keymap.set('n', 'gl', '<cmd>lua vim.diagnostic.open_float()<cr>', opts)
        vim.keymap.set('n', '<F2>', '<cmd>lua vim.lsp.buf.rename()<cr>', opts)
        vim.keymap.set({ 'n', 'x' }, '<F3>', '<cmd>lua vim.lsp.buf.format({async = true})<cr>', opts)
        vim.keymap.set('n', '<F4>', '<cmd>lua vim.lsp.buf.code_action()<cr>', opts)
      end,
    })

    require('mason').setup({})
    require('mason-lspconfig').setup({
      ensure_installed = {
        "awk_ls",    -- AWK
        "bashls",    -- Shell script
        "clangd",    -- C, C++
        "dockerls",  -- Docker, Docker, Docker, Docker!
        "harper_ls", -- English
        "html",
        "markdown_oxide",
        "lua_ls",
        "ruff",     -- Python
        "spectral", -- JSON, YAML
        "texlab",
      },
      handlers = {
        -- This first function is the "default handler"
        -- it applies to every language server without a custom handler
        function(server_name)
          require('lspconfig')[server_name].setup({})
        end,

        -- this is the "custom handler" for `lua_ls`
        lua_ls = function()
          require('lspconfig').lua_ls.setup({
            settings = {
              Lua = {
                runtime = {
                  version = 'LuaJIT',
                },
                diagnostics = {
                  globals = { 'vim' },
                },
                workspace = {
                  library = { vim.env.VIMRUNTIME },
                },
              },
            },
          })
        end,
      },
    })

    local cmp = require('cmp')

    require("luasnip.loaders.from_vscode").load({ paths = os.getenv("HOME") .. "/.config/Code/User/snippets/" })
    require('luasnip.loaders.from_vscode').lazy_load()

    vim.opt.completeopt = { 'menu', 'menuone', 'noselect' }

    cmp.setup({
      preselect = 'item',
      completion = {
        completeopt = 'menu,menuone,noinsert'
      },
      window = {
        documentation = cmp.config.window.bordered(),
      },
      sources = {
        { name = 'path' },
        { name = 'nvim_lsp' },
        { name = 'buffer',  keyword_length = 3 },
        { name = 'luasnip', keyword_length = 2 },
      },
      snippet = {
        expand = function(args)
          require('luasnip').lsp_expand(args.body)
        end,
      },
      formatting = {
        fields = { 'abbr', 'menu', 'kind' },
        format = function(entry, item)
          local n = entry.source.name
          if n == 'nvim_lsp' then
            item.menu = '[LSP]'
          else
            item.menu = string.format('[%s]', n)
          end
          return item
        end,
      },
      mapping = cmp.mapping.preset.insert({
        -- confirm completion item
        ['<CR>'] = cmp.mapping.confirm({ select = false }),

        -- scroll documentation window
        ['<C-f>'] = cmp.mapping.scroll_docs(5),
        ['<C-u>'] = cmp.mapping.scroll_docs(-5),

        -- toggle completion menu
        ['<C-e>'] = cmp.mapping(function(fallback)
          if cmp.visible() then
            cmp.abort()
          else
            cmp.complete()
          end
        end),

        -- tab complete
        ['<Tab>'] = cmp.mapping(function(fallback)
          local col = vim.fn.col('.') - 1

          if cmp.visible() then
            cmp.select_next_item({ behavior = 'select' })
          elseif col == 0 or vim.fn.getline('.'):sub(col, col):match('%s') then
            fallback()
          else
            cmp.complete()
          end
        end, { 'i', 's' }),

        -- go to previous item
        ['<S-Tab>'] = cmp.mapping.select_prev_item({ behavior = 'select' }),

        -- navigate to next snippet placeholder
        ['<C-d>'] = cmp.mapping(function(fallback)
          local luasnip = require('luasnip')

          if luasnip.jumpable(1) then
            luasnip.jump(1)
          else
            fallback()
          end
        end, { 'i', 's' }),

        -- navigate to the previous snippet placeholder
        ['<C-b>'] = cmp.mapping(function(fallback)
          local luasnip = require('luasnip')

          if luasnip.jumpable(-1) then
            luasnip.jump(-1)
          else
            fallback()
          end
        end, { 'i', 's' }),
      }),
    })
  end
}
