-- Aliases
local cmd = vim.cmd
local fn = vim.fn
local g = vim.g
local opt = vim.opt
local map = vim.api.nvim_set_keymap

-- Helpers
local function noremap(mode, lhs, rhs, opts)
    local options = { noremap = true }
    if opts then options = vim.tbl_extend('force', options, opts) end
    vim.api.nvim_set_keymap(mode, lhs, rhs, options)
end

local function associate_filetype(glob, ft)
    cmd('autocmd BufRead,BufNewFile ' .. glob .. ' set filetype=' .. ft)
end
local function setup_filetype(ft, tab, expandtab, opts)
    local cmdline = 'autocmd Filetype ' .. ft .. ' setlocal'
    if tab then cmdline = cmdline .. ' ts=' .. tab .. ' sw=' .. tab .. ' sts=' .. tab end
    if opts then cmdline = cmdline .. ' ' .. opts end -- FIXME: opts should be a table
    cmd(cmdline)
end

local has_words_before = function()
    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

-- Display
opt.number = true -- line numbers
opt.colorcolumn = { '80' } -- line at 80 characters
opt.scrolloff = 5 -- context at top/bottom
opt.sidescrolloff = 8 -- context on the left/right side
opt.conceallevel = 1 -- conceal inactive lines

opt.termguicolors = true
cmd('colorscheme solarized')

-- Undo
opt.undofile = true
opt.undolevels = 4096
opt.undoreload = 16384

-- Behaviour
opt.hidden = true -- background buffers
opt.expandtab = true -- spaces instead of tabs by default
opt.smartindent = true -- automatic indentation
opt.tabstop = 2 -- tabs have width of 2 by default
opt.shiftwidth = 0 -- shift width = tab width
opt.joinspaces = false -- no double spaces when joining
opt.clipboard = 'unnamedplus' -- use system clipboard
opt.modeline = true

cmd([[
autocmd BufReadPost * if line("'\"") >= 1 && line("'\"") <= line("$") && &ft !~# 'commit' | exe "normal! g`\"" | endif
]]) -- see :h last-position-jump

-- Search
opt.ignorecase = true -- ignore case
opt.smartcase = true -- but only with all-lowercase searches

-- Highlight trailing spaces
cmd([[autocmd BufWinEnter * match errorMsg /\s\+$\| \+\ze\t/]])

-- Mappings
g.mapleader = ','

noremap('n', '<CR>', ':nohlsearch<CR>', { silent = true }) -- hide highlights on enter
noremap('v', '<Leader>s', ':sort<CR>') -- sort in visual mode
noremap('t', '<Esc><Esc>', [[<C-\><C-n>]])

-- Filetypes
associate_filetype('*.vpy', 'python') -- vapoursynth scripts

setup_filetype('bib', 1)
setup_filetype('c', 4)
setup_filetype('cpp', 4)
setup_filetype('dockerfile', 4)
setup_filetype('gitcommit', nil, 'colorcolumn=72')
setup_filetype('go', 4, 'noexpandtab')
setup_filetype('haskell', 4)
setup_filetype('lua', 4)
setup_filetype('python', 4)
setup_filetype('sh', 4, 'noexpandtab')
setup_filetype('tex', 1)
setup_filetype('zsh', 4)

-- Plugins

-- Status line
local custom_solarized_lualine = require('lualine.themes.solarized')
-- default colours are very hard to read
custom_solarized_lualine.normal.b = { fg = '#eee8d5', bg = '#586e75' }
require('lualine').setup {
    options = {
        theme = custom_solarized_lualine,
    },
    sections = {
        lualine_c = {
            'filename',
            'lsp_progress',
        },
    },
}

-- Tagbar
noremap('n', '<F8>', ':TagbarToggle<CR>')

-- Keymap popup
require('which-key').setup {}

-- Icons
require('nvim-web-devicons').setup { default = true }

-- Git
require('plenary') -- otherwise neogit SIGABRTs
require('neogit').setup {
    disable_commit_confirmation = true,
    integrations = {
        diffview = true,
    },
}
cmd([[
hi NeogitNotificationInfo guifg=#268bd2
hi NeogitNotificationWarning guifg=#cb4b16
hi NeogitNotificationError guifg=#dc322f
]])
require('gitsigns').setup()
require('diffview').setup {}

-- Fuzzy finder/option picker
require('telescope').setup {}

-- Completion/Snippets
local cmp = require('cmp')
local lspkind = require('lspkind')
local luasnip = require('luasnip')
luasnip.config.set_config {
    enable_autosnippets = true,
}

require('snippets')

cmp.setup {
    snippet = {
        expand = function(args) luasnip.lsp_expand(args.body) end,
    },
    mapping = {
        ['<C-d>'] = cmp.mapping(cmp.mapping.scroll_docs(-4), { 'i', 'c' }),
        ['<C-f>'] = cmp.mapping(cmp.mapping.scroll_docs(4), { 'i', 'c' }),
        ['<C-e>'] = cmp.mapping({ i = cmp.mapping.abort(), c = cmp.mapping.close() }),
        ['<CR>'] = cmp.mapping.confirm({ select = false }),

        ['<Tab>'] = cmp.mapping(function(fallback)
            if luasnip.expand_or_jumpable() then
                luasnip.expand_or_jump()
            elseif cmp.visible() then
                cmp.select_next_item()
            elseif has_words_before() then
                cmp.complete()
            else
                fallback()
            end
        end, { 'i', 's' }),

        ['<S-Tab>'] = cmp.mapping(function(fallback)
            if luasnip.jumpable(-1) then
                luasnip.jump(-1)
            elseif cmp.visible() then
                cmp.select_prev_item()
            else
                fallback()
            end
        end, { 'i', 's' }),
    },
    sources = cmp.config.sources({
        { name = 'nvim_lsp' },
        { name = 'luasnip' },
        { name = 'path' }
    }, {
        {
            name = 'buffer',
            opts = {
                keyword_pattern = [[\k\+]], -- allow unicode multibyte characters
            },
        }
    }),
    formatting = {
        format = lspkind.cmp_format({
            with_text = false,
            maxwidth = 50,
        })
    },
}

-- LSP
local lsp = require('lspconfig')

vim.lsp.handlers['textDocument/publishDiagnostics'] = vim.lsp.with(vim.lsp.diagnostic.on_publish_diagnostics, {
    update_in_insert = true, -- update suggestions in insert mode
})

for type, icon in pairs({ Error = ' ', Warning = ' ', Hint = ' ', Information = ' ' }) do
    local hl = 'LspDiagnosticsSign' .. type
    fn.sign_define(hl, { text = icon, texthl = hl, numhl = hl })
end

local on_attach = function(client, bufnr)
    local function buf_set_keymap(...) vim.api.nvim_buf_set_keymap(bufnr, ...) end
    local function buf_set_option(...) vim.api.nvim_buf_set_option(bufnr, ...) end

    buf_set_option('omnifunc', 'v:lua.vim.lsp.omnifunc')

    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 require("telescope.builtin").lsp_definitions()<CR>', opts)
    buf_set_keymap('n', 'K', '<cmd>lua vim.lsp.buf.hover()<CR>', opts)
    buf_set_keymap('n', 'gi', '<cmd>lua require("telescope.builtin").lsp_implementations()<CR>', opts)
    buf_set_keymap('n', '<C-k>', '<cmd>lua vim.lsp.buf.signature_help()<CR>', opts)
    buf_set_keymap('n', '<Leader>wa', '<cmd>lua vim.lsp.buf.add_workspace_folder()<CR>', opts)
    buf_set_keymap('n', '<Leader>wr', '<cmd>lua vim.lsp.buf.remove_workspace_folder()<CR>', opts)
    buf_set_keymap('n', '<Leader>wl', '<cmd>lua print(vim.inspect(vim.lsp.buf.list_workspace_folders()))<CR>', opts)
    buf_set_keymap('n', '<Leader>D', '<cmd>lua require("telescope.builtin").lsp_type_definitions()<CR>', opts)
    buf_set_keymap('n', '<Leader>rn', '<cmd>lua vim.lsp.buf.rename()<CR>', opts)
    buf_set_keymap('n', '<Leader>ca', '<cmd>lua require("telescope.builtin").lsp_code_actions()<CR>', opts)
    buf_set_keymap('n', 'gr', '<cmd>lua vim.lsp.buf.references()<CR>', opts)
    buf_set_keymap('n', '<Leader>d', '<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>q', '<cmd>lua vim.lsp.diagnostic.set_loclist()<CR>', opts)
    buf_set_keymap('n', '<Leader>f', '<cmd>lua vim.lsp.buf.formatting()<CR>', opts)
end

lsp.gopls.setup {
    on_attach = on_attach,
}
lsp.hls.setup {
    on_attach = on_attach,
    root_dir = lsp.util.root_pattern('*.cabal', 'stack.yaml', 'cabal.project', 'package.yaml', 'hie.yaml', '.git'),
}
lsp.pylsp.setup {
    on_attach = on_attach,
}
lsp.rnix.setup {
    on_attach = on_attach,
}
lsp.rust_analyzer.setup {
    on_attach = on_attach,
    settings = {
        ['rust-analyzer'] = {
            checkOnSave = {
                command = 'clippy',
            },
        },
    },
}

require('trouble').setup {}

-- VimTeX
g.tex_flavor = 'latex'
g.vimtex_view_method = 'zathura'
g.tex_conceal = 'abdmg'

-- this disables some helful warnings that often have a reason why I ignore them
g.vimtex_quickfix_ignore_filters = {
    [[Underfull \\hbox (badness [0-9]*) in ]],
    [[Overfull \\hbox ([0-9]*.[0-9]*pt too wide) in ]],
    [[Overfull \\vbox ([0-9]*.[0-9]*pt too high) detected ]],
    [[Package hyperref Warning: Token not allowed in a PDF string]],
    [[Package typearea Warning: Bad type area settings!]],
}

-- When using math environments vim does not know if if it currently is in one or outside of one
-- unless it parses the file from the start.
-- Parsing the file from the start each time fixes this
-- but leads to a performance drop (depending on the number of lines).
-- Also, somehow using FileType tex does not work, so this will enable slow syntax highlighting
-- everywhere once a *.tex file is opened.
cmd([[autocmd BufEnter *.tex syntax sync fromstart]])

-- rust.vim
g.rustfmt_autosave_if_config_present = 1
g.rust_fold = 1
noremap('n', '<Leader>rt', ':RustTest<CR>')

-- Markdown
g.vim_markdown_folding_disabled = 1