-- https://github.com/LazyVim/LazyVim/blob/main/lua/lazyvim/util/root.lua

local lazy_util = require('lib.lazy.util')
local lazyvim_lsp = require('lib.lazyvim.lsp')

---@class lib.lazyvim.root
---@overload fun(): string
local M = setmetatable({}, {
  __call = function(m)
    return m.get()
  end,
})

---@class LazyRoot
---@field paths string[]
---@field spec LazyRootSpec

---@alias LazyRootFn fun(buf:number): (string|string[])
---@alias LazyRootSpec string|string[]|LazyRootFn

---@type LazyRootSpec[]
M.spec = { 'lsp', { '.git', 'lua' }, 'cwd' }

M.detectors = {}

function M.detectors.cwd()
  return { vim.uv.cwd() }
end

function M.realpath(path)
  if path == '' or path == nil then
    return nil
  end

  path = vim.uv.fs_realpath(path) or path

  return lazy_util.norm(path)
end

function M.bufpath(buf)
  return M.realpath(vim.api.nvim_buf_get_name(assert(buf)))
end

function M.detectors.lsp(buf)
  local bufpath = M.bufpath(buf)

  if not bufpath then
    return {}
  end

  local roots = {} ---@type string[]
  local clients = lazyvim_lsp.get_clients({ bufnr = buf })

  clients = vim.tbl_filter(function(client)
    return not vim.tbl_contains(vim.g.root_lsp_ignore or {}, client.name)
  end, clients)

  for _, client in pairs(clients) do
    local workspace = client.config.workspace_folders

    for _, ws in pairs(workspace or {}) do
      roots[#roots + 1] = vim.uri_to_fname(ws.uri)
    end

    if client.root_dir then
      roots[#roots + 1] = client.root_dir
    end
  end

  return vim.tbl_filter(function(path)
    path = lazy_util.norm(path)

    return path and bufpath:find(path, 1, true) == 1
  end, roots)
end

---@param patterns string[]|string
function M.detectors.pattern(buf, patterns)
  if type(patterns) == 'string' then
    patterns = { patterns }
  end

  local path = M.bufpath(buf) or vim.uv.cwd()
  local pattern = vim.fs.find(function(name)
    for _, p in ipairs(patterns) do
      if name == p then
        return true
      end

      if p:sub(1, 1) == '*' and name:find(vim.pesc(p:sub(2)) .. '$') then
        return true
      end
    end

    return false
  end, { path = path, upward = true })[1]

  return pattern and { vim.fs.dirname(pattern) } or {}
end

---@param spec LazyRootSpec
---@return LazyRootFn
function M.resolve(spec)
  if M.detectors[spec] then
    return M.detectors[spec]
  elseif type(spec) == 'function' then
    return spec
  end

  return function(buf)
    return M.detectors.pattern(buf, spec)
  end
end

---@param opts? {buf?:number, spec?:LazyRootSpec[], all?:boolean}
function M.detect(opts)
  opts = opts or {}
  opts.spec = opts.spec
    or type(vim.g.root_spec) == 'table' and vim.g.root_spec
    or M.spec
  opts.buf = (opts.buf == nil or opts.buf == 0)
      and vim.api.nvim_get_current_buf()
    or opts.buf

  local ret = {} ---@type LazyRoot[]

  for _, spec in ipairs(opts.spec) do
    local paths = M.resolve(spec)(opts.buf)

    paths = paths or {}
    paths = type(paths) == 'table' and paths or { paths }

    local roots = {} ---@type string[]

    for _, p in ipairs(paths) do
      local pp = M.realpath(p)

      if pp and not vim.tbl_contains(roots, pp) then
        roots[#roots + 1] = pp
      end
    end

    table.sort(roots, function(a, b)
      return #a > #b
    end)

    if #roots > 0 then
      ret[#ret + 1] = { spec = spec, paths = roots }

      if opts.all == false then
        break
      end
    end
  end

  return ret
end

---@type table<number, string>
M.cache = {}

-- Returns the root directory based on:
-- * lsp workspace folders
-- * lsp root_dir
-- * root pattern of filename of the current buffer
-- * root pattern of cwd
---@param opts? {normalize?:boolean, buf?:number}
function M.get(opts)
  opts = opts or {}

  local buf = opts.buf or vim.api.nvim_get_current_buf()
  local ret = M.cache[buf]

  if not ret then
    local roots = M.detect({ all = false, buf = buf })

    ret = roots[1] and roots[1].paths[1] or vim.uv.cwd()

    M.cache[buf] = ret
  end

  return ret
end

function M.git()
  local root = M.get()
  local git_root = vim.fs.find('.git', { path = root, upward = true })[1]
  local ret = git_root and vim.fn.fnamemodify(git_root, ':h') or root

  return ret
end

function M.cwd()
  return M.realpath(vim.uv.cwd()) or ''
end

return M