local M = {}

function M.lsp_conf()
    local lspconf = require('lspconfig')

    local on_attach = function(client, bufnr)
        vim.api.nvim_buf_set_option(bufnr, 'omnifunc', 'v:lua.vim.lsp.omnifunc')

        local function buf_set_keymap(...)
            vim.api.nvim_buf_set_keymap(bufnr, ...)
        end

        local opts = {noremap = true, silent = true}
        buf_set_keymap('n', 'gD', '<Cmd>lua vim.lsp.buf.declaration()<CR>', opts)
        buf_set_keymap('n', 'gd', '<Cmd>lua vim.lsp.buf.definition()<CR>', opts)
        buf_set_keymap('n', 'K', '<Cmd>lua vim.lsp.buf.hover()<CR>', opts)
        buf_set_keymap('n', 'gi', '<Cmd>lua vim.lsp.buf.implementation()<CR>', opts)
        buf_set_keymap('n', '<leader>lx', '<Cmd>lua vim.lsp.buf.signature_help()<CR>', opts)
        buf_set_keymap('n', '<leader>la', '<Cmd>lua vim.lsp.buf.add_workspace_folder()<CR>', opts)
        buf_set_keymap('n', '<leader>lr', '<Cmd>lua vim.lsp.buf.remove_workspace_folder()<CR>', opts)
        buf_set_keymap('n', '<leader>lw', '<Cmd>lua print(vim.inspect(vim.lsp.buf.list_workspace_folders()))<CR>', opts)
        buf_set_keymap('n', '<leader>ld', '<Cmd>lua vim.lsp.buf.type_definition()<CR>', opts)
        buf_set_keymap('n', '<leader>ln', '<Cmd>lua vim.lsp.buf.rename()<CR>', opts)
        buf_set_keymap('n', 'gr', '<Cmd>lua vim.lsp.buf.references()<CR>', opts)
        buf_set_keymap('n', '<leader>le', '<Cmd>lua vim.lsp.diagnostic.show_line_diagnostics()<CR>', opts)
        buf_set_keymap('n', '[d', '<Cmd>lua vim.lsp.diagnostic.goto_prev()<CR>', opts)
        buf_set_keymap('n', ']d', '<Cmd>lua vim.lsp.diagnostic.goto_next()<CR>', opts)
        buf_set_keymap('n', '<leader>ll', '<Cmd>lua vim.lsp.diagnostic.set_loclist()<CR>', opts)

        if client.resolved_capabilities.document_formatting then
            buf_set_keymap('n', '<leader>lo', '<Cmd>lua vim.lsp.buf.formatting()<CR>', opts)
        elseif client.resolved_capabilities.document_range_formatting then
            buf_set_keymap('n', '<leader>lo', '<Cmd>lua vim.lsp.buf.range_formatting({},{0,0},{vim.fn.line("$"),0})<CR>', opts)
        end

        -- Attach lsp_signature.nvim
        require('lsp_signature').on_attach({
            bind = true, -- This is mandatory, otherwise border config doesn't work
            floating_window = true,
            fix_pos = true,
            hint_prefix = '🐬 ',
            transpancy = 5,
            handler_opts = {border = 'none'},
            zindex = 50, -- set to 200 to make the float window on top of others
            toggle_key = '<M-x>'
        }, bufnr)
    end

    -- Add additional capabilities supported by nvim-cmp
    local capabilities = vim.lsp.protocol.make_client_capabilities()
    capabilities.textDocument.completion.completionItem.documentationFormat = {'markdown', 'plaintext'}
    capabilities.textDocument.completion.completionItem.snippetSupport = true
    capabilities.textDocument.completion.completionItem.preselectSupport = true
    capabilities.textDocument.completion.completionItem.insertReplaceSupport = true
    capabilities.textDocument.completion.completionItem.labelDetailsSupport = true
    capabilities.textDocument.completion.completionItem.deprecatedSupport = true
    capabilities.textDocument.completion.completionItem.commitCharactersSupport = true
    capabilities.textDocument.completion.completionItem.tagSupport = {valueSet = {1}}
    capabilities.textDocument.completion.completionItem.resolveSupport = {
        properties = {
            'documentation',
            'detail',
            'additionalTextEdits',
        },
    }

    ---------------------------
    -- Server configurations --
    ---------------------------
    -- https://github.com/neovim/nvim-lspconfig/blob/master/CONFIG.md

    -- C/C++
    lspconf.clangd.setup {
        on_attach = on_attach,
        capabilities = capabilities,
        filetypes = {'c', 'cpp'},
        cmd = {
            'clangd',
            '-j=2',
            '--background-index',
            '--clang-tidy',
            '--completion-style=detailed',
            '--pch-storage=memory',
            '--header-insertion=iwyu',
            '--header-insertion=decorators'
        }
    }

    -- Lua
    local runtime_path = vim.split(package.path, ';')
    table.insert(runtime_path, 'lua/?.lua')
    table.insert(runtime_path, 'lua/?/init.lua')

    lspconf.sumneko_lua.setup {
        on_attach = on_attach,
        capabilities = capabilities,
        cmd = {
            vim.fn.stdpath('data') .. '/lsp/lua-language-server/bin/Linux/lua-language-server',
            '-E',
            vim.fn.stdpath('data') .. '/lsp/lua-language-server/main.lua'
        },
        settings = {
            Lua = {
                diagnostics = {
                    globals = {'vim'}
                },
                runtime = {
                    version = 'LuaJIT',
                    path = runtime_path
                },
                workspace = {
                    library = vim.api.nvim_get_runtime_file('', true),
                    maxPreload = 100000,
                    preloadFileSize = 100000
                },
                telemetry = {
                    enable = false
                }
            }
        }
    }

    -- Go
    lspconf.gopls.setup {
        on_attach = on_attach,
        capabilities = capabilities,
        cmd = {'gopls', '--remote=auto'},
        init_options = {
            usePlaceholders = true,
            completeUnimported = true
        }
    }

    -- Emmet
    if not lspconf.emmet_ls then
        require('lspconfig/configs').emmet_ls = {
            default_config = {
                cmd = {'emmet-ls', '--stdio'},
                filetypes = {'html', 'css'},
                root_dir = function(fname)
                    return vim.loop.cwd()
                end,
                settings = {}
            }
        }
    end
    lspconf.emmet_ls.setup {capabilities = capabilities}

    -- Others
    local servers = {
        'dockerls',
        'bashls',
        'pyright',
        'tsserver',
        'html',
        'jsonls',
        'cmake',
        'sqls',
        'rust_analyzer'
    }
    for _, server in ipairs(servers) do
        lspconf[server].setup {
            on_attach = on_attach,
            capabilities = capabilities
        }
    end

    -- Replace the default lsp diagnostic letters with prettier symbols
    vim.fn.sign_define('LspDiagnosticsSignError', {text = ''})
    vim.fn.sign_define('LspDiagnosticsSignWarning', {text = ''})
    vim.fn.sign_define('LspDiagnosticsSignInformation', {text = ''})
    vim.fn.sign_define('LspDiagnosticsSignHint', {text = ''})
end

function M.sqls_conf()
    require('sqls').setup {
        picker = 'telescope'
    }
end

function M.trouble_conf()
    require('trouble').setup {
        mode = 'lsp_workspace_diagnostics',
        fold_open = ' ',
        fold_closed = '',
        action_keys = {
            open_split = {'<c-h>'},
            open_vsplit = {'<c-v>'},
            open_tab = {'<c-t>'}
        },
        signs = {
            error = '',
            warning = '',
            hint = '',
            information = '',
            other = ''
        }
    }
end

function M.outline_conf()
    vim.g.symbols_outline = {
        highlight_hovered_item = false,
        show_guides = false
    }
end

function M.lint_conf()
    require('lint').linters_by_ft = {
        markdown = {'vale', 'markdownlint', 'languagetool'},
        tex = {'vale', 'languagetool'},
        vim = {'vint'},
        -- lua = {'luacheck'},
        c = {'clangtidy', 'cppcheck'},
        cpp = {'clangtidy', 'clazy', 'cppcheck'},
        python = {'pylint', 'flake8', 'pycodestyle'},
        go = {'revive', 'golangcilint'},
        sh = {'shellcheck'},
        bash = {'shellcheck'},
        zsh = {'shellcheck'},
        html = {'tidy', 'stylelint'},
        css = {'stylelint'},
        scss = {'stylelint'},
        sass = {'stylelint'},
        javascript = {'eslint', 'stylelint'}
    }
    -- TODO: custom cmds for linters installed with pip (using virtualenv)
    -- vint, pylint, flake8, pycodestyle, codespell
    vim.api.nvim_command [[ au BufRead,BufWritePost * lua require('lint').try_lint() ]]
end

function M.dap_conf()
    local dap = require('dap')
    vim.fn.sign_define('DapBreakpoint', {text='', texthl='Red'})
    vim.fn.sign_define('DapLogPoint', {text='', texthl='Red'})
    vim.fn.sign_define('DapStopped', {text='', texthl='Red'})
    vim.fn.sign_define('DapBreakpointRejected', {text='ﱢ', texthl='Red'})
end

function M.dapui_conf()
end

return M