local M = {}

local config = {
    bg = "#202020",
    fg = "#ffffff",
    separator = " │ ",
}

local mode_names = {
    ["n"] = "NORMAL",
    ["no"] = "NORMAL",
    ["nov"] = "NORMAL",
    ["noV"] = "NORMAL",
    ["no\22"] = "NORMAL",
    ["niI"] = "NORMAL",
    ["niR"] = "NORMAL",
    ["niV"] = "NORMAL",

    ["i"] = "INSERT",
    ["ic"] = "INSERT",
    ["ix"] = "INSERT",

    ["v"] = "VISUAL",
    ["V"] = "V-LINE",
    ["\22"] = "V-BLOCK",

    ["s"] = "SELECT",
    ["S"] = "S-LINE",
    ["\19"] = "S-BLOCK",

    ["R"] = "REPLACE",
    ["Rc"] = "REPLACE",
    ["Rv"] = "V-REPLACE",

    ["c"] = "COMMAND",
    ["cv"] = "COMMAND",
    ["ce"] = "COMMAND",

    ["r"] = "PROMPT",
    ["rm"] = "MORE",
    ["r?"] = "CONFIRM",

    ["!"] = "SHELL",
    ["t"] = "TERMINAL",
}

local function mode()
    return mode_names[vim.fn.mode()] or "UNKNOWN"
end

local function filename()
    local name = vim.fn.expand("%:t")

    if name == "" then
        return "[No Name]"
    end

    return name
end

local function git_branch()
    local branch = vim.b.gitsigns_head

    if branch and branch ~= "" then
        return " " .. branch
    end

    return ""
end

local function filetype()
    if vim.bo.filetype == "" then
        return "text"
    end

    return vim.bo.filetype
end

local function active_lsp()
    local clients = vim.lsp.get_clients({
        bufnr = 0,
    })

    if #clients == 0 then
        return "-"
    end

    local names = {}

    for _, client in ipairs(clients) do
        table.insert(names, client.name)
    end

    return table.concat(names, ",")
end

local function diagnostics()
    local errors = #vim.diagnostic.get(0, {
        severity = vim.diagnostic.severity.ERROR,
    })

    if errors > 0 then
        return "%#StatusError#●%*"
    end

    local warnings = #vim.diagnostic.get(0, {
        severity = vim.diagnostic.severity.WARN,
    })

    if warnings > 0 then
        return "%#StatusWarn#●%*"
    end

    return "%#StatusNormal#●%*"
end

local function position()
    return string.format("%d:%d", vim.fn.line("."), vim.fn.col("."))
end

local function build()
    local left = table.concat({
        " ",
        mode(),
        config.separator,
        diagnostics(),
        config.separator,
        filename(),
    })

    local right = {}

    local branch = git_branch()

    if branch ~= "" then
        table.insert(right, branch)
    end

    table.insert(right, filetype())
    table.insert(right, active_lsp())
    table.insert(right, position())

    return left
        .. "%="
        .. " "
        .. table.concat(right, config.separator)
        .. " "
end

function M.setup(opts)
    config = vim.tbl_extend("force", config, opts or {})

    vim.api.nvim_set_hl(0, "StatusLine", {
        fg = config.fg,
        bg = config.bg,
    })

    vim.api.nvim_set_hl(0, "StatusLineNC", {
        fg = config.fg,
        bg = config.bg,
    })

    vim.api.nvim_set_hl(0, "StatusNormal", {
        fg = "#808080",
        bg = config.bg,
    })

    vim.api.nvim_set_hl(0, "StatusLsp", {
        fg = "#61afef",
        bg = config.bg,
    })

    vim.api.nvim_set_hl(0, "StatusWarn", {
        fg = "#e5c07b",
        bg = config.bg,
    })

    vim.api.nvim_set_hl(0, "StatusError", {
        fg = "#e06c75",
        bg = config.bg,
    })

    _G.StatusBar = build

    vim.o.statusline = "%!v:lua.StatusBar()"
end

return M