local cmp = require("cmp")
local nvim_lsp = require("lspconfig")
local cmp_window = require("cmp.utils.window")

vim.o.completeopt = "menuone,noselect"
vim.o.shortmess = vim.o.shortmess .. "c"

local function on_attach(client, bufn)
    local function map(...)
        vim.api.nvim_buf_set_keymap(bufn, ...)
    end

    local function buf_set_option(...)
	vim.api.nvim_buf_set_option(bufn, ...)
    end

    local opts = { noremap = true, silent = true }
    map("n", "gD", "<Cmd>lua vim.lsp.buf.declaration()<CR>", opts)
    map("n", "gd", "<Cmd>lua vim.lsp.buf.definition()<CR>", opts)
    map("n", "K", "<Cmd>lua vim.lsp.buf.hover()<CR>", opts)
    map("n", "gi", "<Cmd>lua vim.lsp.buf.implementation()<CR>", opts)
    map("n", "<C-k>", "<Cmd>lua vim.lsp.buf.signature_help()<CR>", opts)
    map("n", "<leader>D", "<Cmd>lua vim.lsp.buf.type_definition()<CR>", opts)
    map("n", "gr", "<Cmd>lua vim.lsp.buf.references()<CR>", opts)
    map("n", "<leader>e", "<cmd>lua vim.lsp.diagnostic.show_line_diagnostics()<CR>", opts)
    map("n", "[d", "<Cmd>lua vim.lsp.diagnostic.goto_prev()<CR>", opts)
    map("n", "]d", "<Cmd>lua vim.lsp.diagnostic.goto_next()<CR>", opts)
    map("n", "<leader>q", "<Cmd>lua vim.lsp.diagnostic.set_loclist()<CR>", opts)
    map("n", "ga", "<Cmd>lua vim.lsp.buf.code_action()<CR>", opts)
end

local function has_words_before()
    local line, col = unpack(vim.api.nvim_win_get_cursor(0))
    return col ~= 0 and vim.api.nvim_buf_get_lines(0, line - 1, line, true)[1]:sub(col, col):match("%s") == nil
end

local function feedkey(key, mode)
    vim.api.nvim_feedkeys(vim.api.nvim_replace_termcodes(key, true, true, true), mode, true)
end

local function border(hl_name)
    return {
        { "╭", hl_name },
        { "─", hl_name },
        { "╮", hl_name },
        { "│", hl_name },
        { "╯", hl_name },
        { "─", hl_name },
        { "╰", hl_name },
        { "│", hl_name },
    }
end

cmp_window.info_ = cmp_window.info
cmp_window.info = function(self)
    local info = self:info_()
    info.scrollable = false
    return info
end

cmp.setup({
    window = {
        completion = {
            border = border "CmpBorder",
            winhighlight = "Normal:CmpPmenu,CursorLine:PmenuSel,Search:None",
        },
        documentation = {
            border = border "CmpDocBorder"
        },
    },
    snippet = {
        expand = function(args)
            vim.fn["vsnip#anonymous"](args.body)
        end,
    },
    mapping = cmp.mapping.preset.insert({
        ['<C-b>'] = cmp.mapping.scroll_docs(-4),
        ['<C-f>'] = cmp.mapping.scroll_docs(4),
        ['<C-Space>'] = cmp.mapping.complete(),
        ['<C-e>'] = cmp.mapping.abort(),
        ['<CR>'] = cmp.mapping.confirm({select = true}),
        ["<Tab>"] = cmp.mapping(function(fallback)
            if cmp.visible() then
                cmp.select_next_item()
            elseif vim.fn["vsnip#available"](1) == 1 then
                feedkey("<Plug>(vsnip-expand-or-jump)", "")
            elseif has_words_before() then
                cmp.complete()
            else
                fallback()
            end
        end, {"i", "s"}),
 
        ["<S-Tab"] = cmp.mapping(function()
            if cmp.visible() then
                cmp.select_prev_item()
            elseif vim.fn["vsnip#jumpable"](-1) == 1 then
                feedkey("<Plug>(vsnip-jump-prev)", "")
            end
        end, {"i", "s"}),
    }),
    sources = cmp.config.sources({
        { name = "nvim_lsp" },
        { name = "vsnip" },
        { name = "treesitter" },
        { name = "path", option = { trailing_slash = true }},
        { name = "buffer" }
    }),
})

cmp.setup.cmdline(":", {
    mapping = cmp.mapping.preset.cmdline(),
    sources = cmp.config.sources({
        { name = "path" },
    }, {
        { name = "cmdline" },
    }),
})

vim.lsp.handlers["textDocument/publishDiagnostics"] = vim.lsp.with(
    vim.lsp.diagnostic.on_publish_diagnostics, {
        virtual_text = true,
        signs = true,
        update_in_insert = true
    }
)

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

local servers = { "ccls", "bashls", "rnix", "texlab", "lua_ls" }

for _, lang in pairs(servers) do
    nvim_lsp[lang].setup({
        root_dir = vim.loop.cwd,
        on_attach = on_attach,
        capabilities = capabilities
    })
end

require("nvim-treesitter.configs").setup({
    highlight = { enable = true, },
})

require("gitsigns").setup({})