-- Install packer
local install_path = vim.fn.stdpath 'data' ..
                         '/site/pack/packer/start/packer.nvim'
local is_bootstrap = false
if vim.fn.empty(vim.fn.glob(install_path)) > 0 then
    is_bootstrap = true
    vim.fn.system {
        'git', 'clone', '--depth', '1',
        'https://github.com/wbthomason/packer.nvim', install_path
    }
    vim.cmd [[packadd packer.nvim]]
end

require('packer').startup(function(use)
    -- Package manager
    use 'wbthomason/packer.nvim'

    use { -- LSP Configuration & Plugins
        'neovim/nvim-lspconfig',
        requires = {
            -- Automatically install LSPs to stdpath for neovim
            'williamboman/mason.nvim', 'williamboman/mason-lspconfig.nvim',

            -- Useful status updates for LSP
            'j-hui/fidget.nvim',

            -- Additional lua configuration, makes nvim stuff amazing
            'folke/neodev.nvim'
        }
    }

    use { -- Autocompletion
        'hrsh7th/nvim-cmp',
        requires = {
            'hrsh7th/cmp-nvim-lsp', 'hrsh7th/cmp-buffer', 'L3MON4D3/LuaSnip',
            'saadparwaiz1/cmp_luasnip', 'hrsh7th/cmp-path'
        }
    }

    use { -- Highlight, edit, and navigate code
        'nvim-treesitter/nvim-treesitter',
        run = function()
            pcall(require('nvim-treesitter.install').update {with_sync = true})
        end
    }

    use { -- Additional text objects via treesitter
        'nvim-treesitter/nvim-treesitter-textobjects',
        after = 'nvim-treesitter'
    }

    -- Git related plugins
    use 'tpope/vim-fugitive'
    use 'tpope/vim-rhubarb'
    use 'lewis6991/gitsigns.nvim'

    use 'ellisonleao/gruvbox.nvim'
    use 'nvim-lualine/lualine.nvim' -- Fancier statusline
    use 'lukas-reineke/indent-blankline.nvim' -- Add indentation guides even on blank lines
    use 'numToStr/Comment.nvim' -- "gc" to comment visual regions/lines
    use 'tpope/vim-sleuth' -- Detect tabstop and shiftwidth automatically

    -- Fuzzy Finder (files, lsp, etc)
    use {
        'nvim-telescope/telescope.nvim',
        branch = '0.1.x',
        requires = {'nvim-lua/plenary.nvim'}
    }

    -- Fuzzy Finder Algorithm which requires local dependencies to be built. Only load if `make` is available
    use {
        'nvim-telescope/telescope-fzf-native.nvim',
        run = 'make',
        cond = vim.fn.executable 'make' == 1
    }

    use 'LnL7/vim-nix'
    use 'alx741/yesod.vim'
    use '5outh/yesod-routes.vim'

    -- Add custom plugins to packer from ~/.config/nvim/lua/custom/plugins.lua
    local has_plugins, plugins = pcall(require, 'custom.plugins')
    if has_plugins then plugins(use) end

    if is_bootstrap then require('packer').sync() end
end)

-- When we are bootstrapping a configuration, it doesn't
-- make sense to execute the rest of the init.lua.
--
-- You'll need to restart nvim, and then it will work.
if is_bootstrap then
    print '=================================='
    print '    Plugins are being installed'
    print '    Wait until Packer completes,'
    print '       then restart nvim'
    print '=================================='
    return
end

-- Automatically source and re-compile packer whenever you save this init.lua
local packer_group = vim.api.nvim_create_augroup('Packer', {clear = true})
vim.api.nvim_create_autocmd('BufWritePost', {
    command = 'source <afile> | silent! LspStop | silent! LspStart | PackerCompile',
    group = packer_group,
    pattern = vim.fn.expand '$MYVIMRC'
})

-- [[ Setting options ]]
-- See `:help vim.o`

-- Set highlight on search
vim.o.hlsearch = false

-- Make line numbers default
vim.wo.number = true

-- Enable mouse mode
vim.o.mouse = ''

-- Enable break indent
vim.o.breakindent = true

-- Save undo history
vim.o.undofile = true

-- Case insensitive searching UNLESS /C or capital in search
vim.o.ignorecase = true
vim.o.smartcase = true

-- Decrease update time
vim.o.updatetime = 250
vim.wo.signcolumn = 'yes'

-- Set colorscheme
vim.o.termguicolors = true
vim.cmd [[colorscheme gruvbox]]

-- Set completeopt to have a better completion experience
vim.o.completeopt = 'menuone,noselect'

-- [[ Basic Keymaps ]]
-- Set <space> as the leader key
-- See `:help mapleader`
--  NOTE: Must happen before plugins are required (otherwise wrong leader will be used)
vim.g.mapleader = ' '
vim.g.maplocalleader = ' '

-- Keymaps for better default experience
-- See `:help vim.keymap.set()`
vim.keymap.set({'n', 'v'}, '<Space>', '<Nop>', {silent = true})
vim.keymap.set({'n'}, ';', ':', {})
vim.keymap.set({'n'}, '<leader>n', ':set number!<cr>', {})
vim.keymap.set({'n'}, '<leader>s', ':setlocal spell! spell?<cr>', {})
vim.keymap.set({'n'}, '<leader>z', '<c-w><c-w>', {})

vim.keymap.set({'v'}, '<', '<gv', {})
vim.keymap.set({'v'}, '>', '>gv', {})

-- Remap for dealing with word wrap
vim.keymap.set('n', 'k', "v:count == 0 ? 'gk' : 'k'",
               {expr = true, silent = true})
vim.keymap.set('n', 'j', "v:count == 0 ? 'gj' : 'j'",
               {expr = true, silent = true})

-- [[ Highlight on yank ]]
-- See `:help vim.highlight.on_yank()`
local highlight_group = vim.api.nvim_create_augroup('YankHighlight',
                                                    {clear = true})
vim.api.nvim_create_autocmd('TextYankPost', {
    callback = function() vim.highlight.on_yank() end,
    group = highlight_group,
    pattern = '*'
})

-- Set lualine as statusline
-- See `:help lualine.txt`
require('lualine').setup {
    options = {
        icons_enabled = false,
        theme = 'onedark',
        component_separators = '|',
        section_separators = ''
    }
}

-- Enable Comment.nvim
require('Comment').setup()

-- Enable `lukas-reineke/indent-blankline.nvim`
-- See `:help indent_blankline.txt`
require('indent_blankline').setup {
    char = '┊',
    show_trailing_blankline_indent = false
}

-- Gitsigns
-- See `:help gitsigns.txt`
require('gitsigns').setup {
    signs = {
        add = {text = '+'},
        change = {text = '~'},
        delete = {text = '_'},
        topdelete = {text = '‾'},
        changedelete = {text = '~'}
    }
}

-- [[ Configure Telescope ]]
-- See `:help telescope` and `:help telescope.setup()`
require('telescope').setup {
    defaults = {mappings = {i = {['<C-u>'] = false, ['<C-d>'] = false}}}
}

-- Enable telescope fzf native, if installed
pcall(require('telescope').load_extension, 'fzf')

-- See `:help telescope.builtin`
vim.keymap.set('n', '<leader>?', require('telescope.builtin').oldfiles,
               {desc = '[?] Find recently opened files'})
vim.keymap.set('n', '<leader><space>', require('telescope.builtin').buffers,
               {desc = '[ ] Find existing buffers'})
vim.keymap.set('n', '<leader>/', function()
    -- You can pass additional configuration to telescope to change theme, layout, etc.
    require('telescope.builtin').current_buffer_fuzzy_find(require(
                                                               'telescope.themes').get_dropdown {
        winblend = 10,
        previewer = false
    })
end, {desc = '[/] Fuzzily search in current buffer]'})

vim.keymap.set('n', '<leader>sf', require('telescope.builtin').find_files,
               {desc = '[S]earch [F]iles'})
vim.keymap.set('n', '<leader>sh', require('telescope.builtin').help_tags,
               {desc = '[S]earch [H]elp'})
vim.keymap.set('n', '<leader>sw', require('telescope.builtin').grep_string,
               {desc = '[S]earch current [W]ord'})
vim.keymap.set('n', '<leader>sg', require('telescope.builtin').live_grep,
               {desc = '[S]earch by [G]rep'})
vim.keymap.set('n', '<leader>sd', require('telescope.builtin').diagnostics,
               {desc = '[S]earch [D]iagnostics'})

-- [[ Configure Treesitter ]]
-- See `:help nvim-treesitter`
require('nvim-treesitter.configs').setup {
    -- Add languages to be installed here that you want installed for treesitter
    ensure_installed = {
        'c', 'cpp', 'go', 'lua', 'python', 'rust', 'typescript', 'help', 'vim',
        'haskell'
    },

    highlight = {enable = true},
    indent = {enable = true, disable = {'python'}},
    incremental_selection = {
        enable = true,
        keymaps = {
            init_selection = '<c-space>',
            node_incremental = '<c-space>',
            scope_incremental = '<c-s>',
            node_decremental = '<c-backspace>'
        }
    },
    textobjects = {
        select = {
            enable = true,
            lookahead = true, -- Automatically jump forward to textobj, similar to targets.vim
            keymaps = {
                -- You can use the capture groups defined in textobjects.scm
                ['aa'] = '@parameter.outer',
                ['ia'] = '@parameter.inner',
                ['af'] = '@function.outer',
                ['if'] = '@function.inner',
                ['ac'] = '@class.outer',
                ['ic'] = '@class.inner'
            }
        },
        move = {
            enable = true,
            set_jumps = true, -- whether to set jumps in the jumplist
            goto_next_start = {
                [']m'] = '@function.outer',
                [']]'] = '@class.outer'
            },
            goto_next_end = {
                [']M'] = '@function.outer',
                [']['] = '@class.outer'
            },
            goto_previous_start = {
                ['[m'] = '@function.outer',
                ['[['] = '@class.outer'
            },
            goto_previous_end = {
                ['[M'] = '@function.outer',
                ['[]'] = '@class.outer'
            }
        },
        swap = {
            enable = true,
            swap_next = {['<leader>a'] = '@parameter.inner'},
            swap_previous = {['<leader>A'] = '@parameter.inner'}
        }
    }
}

-- Diagnostic keymaps
vim.keymap.set('n', '[d', vim.diagnostic.goto_prev)
vim.keymap.set('n', ']d', vim.diagnostic.goto_next)
vim.keymap.set('n', '<leader>e', vim.diagnostic.open_float)
vim.keymap.set('n', '<leader>q', vim.diagnostic.setloclist)

-- LSP settings.
--  This function gets run when an LSP connects to a particular buffer.
local on_attach = function(_, bufnr)
    -- NOTE: Remember that lua is a real programming language, and as such it is possible
    -- to define small helper and utility functions so you don't have to repeat yourself
    -- many times.
    --
    -- In this case, we create a function that lets us more easily define mappings specific
    -- for LSP related items. It sets the mode, buffer and description for us each time.
    local nmap = function(keys, func, desc)
        if desc then desc = 'LSP: ' .. desc end

        vim.keymap.set('n', keys, func, {buffer = bufnr, desc = desc})
    end

    nmap('<leader>rn', vim.lsp.buf.rename, '[R]e[n]ame')
    nmap('<leader>ca', vim.lsp.buf.code_action, '[C]ode [A]ction')

    nmap('gd', vim.lsp.buf.definition, '[G]oto [D]efinition')
    nmap('gr', require('telescope.builtin').lsp_references,
         '[G]oto [R]eferences')
    nmap('gI', vim.lsp.buf.implementation, '[G]oto [I]mplementation')
    nmap('<leader>D', vim.lsp.buf.type_definition, 'Type [D]efinition')
    nmap('<leader>ds', require('telescope.builtin').lsp_document_symbols,
         '[D]ocument [S]ymbols')
    nmap('<leader>ws',
         require('telescope.builtin').lsp_dynamic_workspace_symbols,
         '[W]orkspace [S]ymbols')

    -- See `:help K` for why this keymap
    nmap('K', vim.lsp.buf.hover, 'Hover Documentation')
    nmap('<C-k>', vim.lsp.buf.signature_help, 'Signature Documentation')

    -- Lesser used LSP functionality
    nmap('gD', vim.lsp.buf.declaration, '[G]oto [D]eclaration')
    nmap('<leader>wa', vim.lsp.buf.add_workspace_folder,
         '[W]orkspace [A]dd Folder')
    nmap('<leader>wr', vim.lsp.buf.remove_workspace_folder,
         '[W]orkspace [R]emove Folder')
    nmap('<leader>wl', function()
        print(vim.inspect(vim.lsp.buf.list_workspace_folders()))
    end, '[W]orkspace [L]ist Folders')

    -- Create a command `:Format` local to the LSP buffer
    vim.api.nvim_buf_create_user_command(bufnr, 'Format',
                                         function(_) vim.lsp.buf.format() end, {
        desc = 'Format current buffer with LSP'
    })
end

-- Setup neovim lua configuration
require('neodev').setup()
--
-- nvim-cmp supports additional completion capabilities, so broadcast that to servers
local capabilities = vim.lsp.protocol.make_client_capabilities()
capabilities = require('cmp_nvim_lsp').default_capabilities(capabilities)

local haskell_cmd
if os.getenv('USE_HALFSP') then
    haskell_cmd = {'halfsp'}
else
    haskell_cmd = {'haskell-language-server-wrapper', '--lsp'}
end
require('lspconfig')['hls'].setup {cmd = haskell_cmd, on_attach = on_attach}
require('lspconfig')['nil_ls'].setup {}
require('lspconfig')['pyright'].setup {}

-- Turn on lsp status information
require('fidget').setup()

-- nvim-cmp setup
local cmp = require 'cmp'
local luasnip = require 'luasnip'

cmp.setup {
    snippet = {expand = function(args) luasnip.lsp_expand(args.body) end},
    mapping = cmp.mapping.preset.insert {
        ['<C-d>'] = cmp.mapping.scroll_docs(-4),
        ['<C-f>'] = cmp.mapping.scroll_docs(4),
        ['<C-Space>'] = cmp.mapping.complete(),
        ['<CR>'] = cmp.mapping.confirm {
            behavior = cmp.ConfirmBehavior.Replace,
            select = true
        },
        ['<Tab>'] = cmp.mapping(function(fallback)
            if cmp.visible() then
                cmp.select_next_item()
            elseif luasnip.expand_or_jumpable() then
                luasnip.expand_or_jump()
            else
                fallback()
            end
        end, {'i', 's'}),
        ['<S-Tab>'] = cmp.mapping(function(fallback)
            if cmp.visible() then
                cmp.select_prev_item()
            elseif luasnip.jumpable(-1) then
                luasnip.jump(-1)
            else
                fallback()
            end
        end, {'i', 's'})
    },
    sources = {
        {name = 'nvim_lsp'}, {name = 'luasnip'}, {name = 'buffer'},
        {name = 'path'}
    }
}

-- The line beneath this is called `modeline`. See `:help modeline`
-- vim: ts=2 sts=2 sw=2 et