nvim-config/lua/plugins/finder.lua

-- finder.lua — Minimal, hardened async fuzzy finder + grep for Neovim ≥ 0.11

local M = {}

---------------------------------------------------------------------
-- Config
---------------------------------------------------------------------
M.config = {
  file_cmd = nil, -- "fd" | "fdfind" | nil (auto-detect)
  grep_cmd = 'rg', -- ripgrep binary
  page_size = 60, -- soft cap; real viewport height is measured
  debounce_ms = 80,
  instant_items = 1500, -- <= this count + cached => 0 ms debounce
  fast_items = 4000, -- <= this count => debounce_ms/2
  cache_ttl_sec = 20,
  max_items = 5000, -- safety cap for massive outputs
  debug = false,
  follow_symlinks = true, -- pass -L to fd
  grep_path_width = 30,

  -- Exclusion patterns (used by fd/rg in addition to their gitignore handling)
  exclude_patterns = { 'node_modules', 'dist', 'build', '.git' },

  -- Optional on-disk filelist cache at $ROOT/.devflow/finder_cache.json
  use_disk_cache = false,
}

---------------------------------------------------------------------
-- State
---------------------------------------------------------------------
local S = {
  active = false,
  mode = nil, -- "files" | "grep"
  root = nil,

  cache = {},
  timer = nil,
  ns = vim.api.nvim_create_namespace('finder_ns'),
  aug = nil,
  gen = 0, -- session generation id

  -- async jobs
  job_files = nil,
  job_rg = nil,

  -- UI
  win_inp = nil,
  buf_inp = nil,
  win_res = nil,
  buf_res = nil,

  -- Data
  query = '',
  items = {}, -- full set (files or grep lines)
  filtered = {}, -- current view
  positions = {}, -- positions[i] = { {scol, ecol}, ... } for filtered[i]
  select = 1, -- absolute index in filtered (1-based)
  scroll = 0, -- top index (0-based)
  user_moved = false, -- has user navigated during this session?

  -- meta
  files_cached = false,
}

---------------------------------------------------------------------
-- Utils
---------------------------------------------------------------------
local function L(msg, data)
  if not M.config.debug then
    return
  end
  local s = '[finder] ' .. msg
  if data ~= nil then
    s = s .. ' ' .. vim.inspect(data)
  end
  vim.schedule(function()
    pcall(vim.notify, s)
  end)
end

local function now_sec()
  return os.time()
end

local function clamp(v, lo, hi)
  return (v < lo) and lo or ((v > hi) and hi or v)
end

local function cmd_exists(bin)
  return vim.fn.executable(bin) == 1
end

-- single reusable timer to avoid churn
local function debounce(fn, ms)
  if not S.timer then
    S.timer = vim.loop.new_timer()
  end
  S.timer:stop()
  S.timer:start(ms, 0, function()
    S.timer:stop()
    vim.schedule(fn)
  end)
end

local function ensure_cache_dir(root)
  local dir = root .. '/.devflow'
  local ok = vim.loop.fs_stat(dir)
  if not ok then
    pcall(vim.loop.fs_mkdir, dir, 448) -- 0700
  end
  return dir
end

local function load_cache(root)
  if not M.config.use_disk_cache then
    return nil
  end
  local file = ensure_cache_dir(root) .. '/finder_cache.json'
  local f = io.open(file, 'r')
  if not f then
    return nil
  end
  local content = f:read('*a')
  f:close()
  local ok, data = pcall(vim.json.decode, content)
  if not ok or type(data) ~= 'table' or type(data.files) ~= 'table' then
    return nil
  end
  if now_sec() - (data.timestamp or 0) > M.config.cache_ttl_sec then
    pcall(os.remove, file)
    return nil
  end
  return data.files
end

local function save_cache(root, files)
  if not M.config.use_disk_cache then
    return
  end
  local file = ensure_cache_dir(root) .. '/finder_cache.json'
  local payload = { timestamp = now_sec(), files = files }
  local ok, json = pcall(vim.json.encode, payload)
  if not ok then
    return
  end
  local f = io.open(file, 'w')
  if not f then
    return
  end
  f:write(json)
  f:close()
end

local function project_root()
  return vim.fn.getcwd(0, 0)
end

-- local function project_root()
--   local obj = vim.system({ 'git', 'rev-parse', '--show-toplevel' }, { text = true }):wait()
--   if obj.code == 0 and obj.stdout and obj.stdout ~= '' then
--     return vim.trim(obj.stdout)
--   end
--   return vim.fn.getcwd(0, 0)
-- end

local function normalize_rel(root, p)
  if not p or p == '' then
    return ''
  end
  local abs = vim.fs.normalize(vim.fn.fnamemodify(p, ':p'))
  local root_norm = vim.fs.normalize(root)
  if abs == root_norm then
    return ''
  end
  if abs:find(root_norm, 1, true) == 1 then
    local ch = abs:sub(#root_norm + 1, #root_norm + 1)
    if ch == '/' or ch == '\\' then
      return abs:sub(#root_norm + 2)
    end
  end
  return (p:gsub('^%./', ''))
end

local function to_abs_path(root, rel)
  if not rel or rel == '' then
    return root
  end
  return vim.fs.normalize(root .. '/' .. rel)
end

local function to_display_path(abs)
  return vim.fn.fnamemodify(abs, ':.')
end

local function page_rows()
  if S.win_res and vim.api.nvim_win_is_valid(S.win_res) then
    return math.max(1, vim.api.nvim_win_get_height(S.win_res))
  end
  return math.max(1, math.min(M.config.page_size, vim.o.lines))
end

local function effective_debounce_ms()
  if S.mode == 'files' then
    local n = #S.items
    if S.files_cached and n > 0 and n <= (M.config.instant_items or 1500) then
      return 0
    elseif n > 0 and n <= (M.config.fast_items or 4000) then
      return math.max(0, math.floor((M.config.debounce_ms or 80) / 2))
    end
  end
  return M.config.debounce_ms or 80
end

---------------------------------------------------------------------
-- Render
---------------------------------------------------------------------
local function ensure_visible()
  local page = page_rows()
  local sel = clamp(S.select, 1, math.max(1, #S.filtered))
  local top = S.scroll + 1
  local bot = S.scroll + page
  if sel < top then
    S.scroll = sel - 1
  elseif sel > bot then
    S.scroll = sel - page
  end
  S.scroll = clamp(S.scroll, 0, math.max(#S.filtered - page, 0))
end

local function render()
  if not (S.buf_res and vim.api.nvim_buf_is_valid(S.buf_res)) then
    return
  end

  ensure_visible()

  local total = #S.filtered
  local view = {}
  if total == 0 then
    view = { '  (no matches)' }
  else
    local start_idx = S.scroll + 1
    local end_idx = math.min(start_idx + page_rows() - 1, total)
    for i = start_idx, end_idx do
      view[#view + 1] = tostring(S.filtered[i] or '')
    end
  end

  -- For grep mode, reformat lines with fixed-width path column
  local offset_map = {} -- maps display line -> character offset for highlighting
  -- In render(), replace the grep reformatting section:
  -- In render(), replace the grep reformatting section:
  if S.mode == 'grep' and total > 0 then
    local path_width = M.config.grep_path_width or 40

    for i = 1, #view do
      local line = view[i]
      if line then
        local file, lnum, col, content_start_pos = line:match('^(.-):(%d+):(%d+):()')
        if file and lnum and col and content_start_pos then
          local padded_lnum = lnum
          while #padded_lnum < 3 do
            padded_lnum = ' ' .. padded_lnum
          end

          local lineinfo = ':' .. padded_lnum .. '|'
          local content_part = line:sub(content_start_pos)

          local prefix_len = #file + #lineinfo
          local formatted_line
          local new_content_start -- 1-based position where content starts in formatted line

          if prefix_len > path_width then
            local available_for_file = path_width - #lineinfo
            if available_for_file > 1 then
              local truncated_file = '…' .. file:sub(-(available_for_file - 1))
              formatted_line = truncated_file .. lineinfo .. content_part
              new_content_start = #truncated_file + #lineinfo + 1
            else
              formatted_line = ('…' .. file):sub(1, path_width) .. lineinfo .. content_part
              new_content_start = path_width + #lineinfo + 1
            end
          elseif prefix_len < path_width then
            local padding = string.rep(' ', path_width - prefix_len)
            formatted_line = padding .. file .. lineinfo .. content_part
            new_content_start = #padding + #file + #lineinfo + 1
          else
            formatted_line = file .. lineinfo .. content_part
            new_content_start = #file + #lineinfo + 1
          end

          view[i] = formatted_line
          offset_map[i] = content_start_pos - new_content_start
        end
      end
    end
  end

  vim.bo[S.buf_res].modifiable = true
  vim.api.nvim_buf_set_lines(S.buf_res, 0, -1, false, view)
  vim.api.nvim_buf_clear_namespace(S.buf_res, S.ns, 0, -1)

  -- highlight groups
  vim.api.nvim_set_hl(0, 'FinderMatch', { link = 'Search', default = true })
  vim.api.nvim_set_hl(0, 'FinderPath', { fg = '#888888', default = true })

  for i = 1, #view do
    local idx = S.scroll + i
    local line = view[i]

    -- In grep mode, highlight the entire "file:line|" prefix in gray
    if S.mode == 'grep' and line then
      -- Find the end of the full prefix including the pipe
      local _, prefix_end = line:find(':[ 0-9]+|')
      if prefix_end then
        pcall(vim.api.nvim_buf_set_extmark, S.buf_res, S.ns, i - 1, 0, {
          end_col = prefix_end,
          hl_group = 'FinderPath',
        })
      end
    end

    -- match highlights (query matches in orange)
    local spans = S.positions[idx]
    if spans then
      for _, se in ipairs(spans) do
        local scol, ecol = se[1], se[2]

        -- Adjust positions for grep mode formatting
        if S.mode == 'grep' and offset_map[i] then
          scol = scol - offset_map[i]
          ecol = ecol - offset_map[i]
        end

        if ecol > scol and scol >= 0 then
          pcall(vim.api.nvim_buf_set_extmark, S.buf_res, S.ns, i - 1, scol, {
            end_col = ecol,
            hl_group = 'FinderMatch',
          })
        end
      end
    end
  end

  -- selection highlight
  if total > 0 then
    vim.api.nvim_set_hl(0, 'FinderSelection', { link = 'CursorLine', default = true })
    local rel = clamp(S.select - S.scroll, 1, #view)
    pcall(vim.api.nvim_buf_set_extmark, S.buf_res, S.ns, rel - 1, 0, {
      end_line = rel,
      hl_group = 'FinderSelection',
      hl_eol = true,
    })
  end

  vim.bo[S.buf_res].modifiable = false
  L('render', { select = S.select, scroll = S.scroll, total = total })
end

---------------------------------------------------------------------
-- Filtering
---------------------------------------------------------------------
local function compute_positions_files(items, q)
  local ok, res = pcall(vim.fn.matchfuzzypos, items, q)
  if not ok or type(res) ~= 'table' then
    return {}, {}
  end
  local out_items = res[1] or {}
  local pos = res[2] or {}

  local filtered, positions = {}, {}
  for i, v in ipairs(out_items) do
    filtered[i] = tostring(v or '')
    local cols = pos[i] or {}
    table.sort(cols)
    local spans = {}
    local start_col, last_col = nil, nil
    for _, c in ipairs(cols) do
      if not start_col then
        start_col, last_col = c, c
      elseif c == last_col + 1 then
        last_col = c
      else
        table.insert(spans, { start_col, last_col + 1 })
        start_col, last_col = c, c
      end
    end
    if start_col then
      table.insert(spans, { start_col, last_col + 1 })
    end
    positions[i] = (#spans > 0) and spans or nil
  end
  return filtered, positions
end

local function compute_positions_grep(lines, q)
  if q == '' then
    return lines, {}
  end
  local case_insensitive = not q:match('[A-Z]')
  local qmatch = case_insensitive and q:lower() or q
  local positions = {}
  for i, line in ipairs(lines) do
    local file, lnum, col, content_start_pos = line:match('^(.-):(%d+):(%d+):()')
    if not content_start_pos then
      positions[i] = nil
    else
      local content = line:sub(content_start_pos)
      local lmatch = case_insensitive and content:lower() or content
      local spans = {}
      local sidx = 1
      while true do
        local s, e = lmatch:find(qmatch, sidx, true)
        if not s then
          break
        end
        -- Use content_start_pos from the pattern match, not manual calculation
        table.insert(spans, { content_start_pos - 1 + s - 1, content_start_pos - 1 + e })
        sidx = e + 1
        if #spans > 64 then
          break
        end
      end
      positions[i] = (#spans > 0) and spans or nil
    end
  end
  return lines, positions
end

---------------------------------------------------------------------
-- set_items / set_query
---------------------------------------------------------------------
local function set_items(list)
  list = list or {}
  if #list > M.config.max_items then
    local tmp = {}
    for i = 1, M.config.max_items do
      tmp[i] = list[i]
    end
    list = tmp
  end

  for i, v in ipairs(list) do
    list[i] = tostring(v or '')
  end

  table.sort(list)

  S.items = list
  S.filtered = list
  S.positions = {}
  S.select = 1
  S.scroll = 0
  render()
end

local function set_query(q)
  local prev_val = S.filtered[S.select]
  S.query = q

  if S.mode == 'grep' then
    local filtered, pos = compute_positions_grep(S.items, q)
    S.filtered, S.positions = filtered, pos
  else
    if q == '' then
      S.filtered = S.items
      S.positions = {}
    else
      local filtered, pos = compute_positions_files(S.items, q)
      S.filtered, S.positions = filtered, pos
    end
  end

  if not S.user_moved then
    S.select = 1
  else
    local idx = nil
    if prev_val then
      for i, v in ipairs(S.filtered) do
        if v == prev_val then
          idx = i
          break
        end
      end
    end
    S.select = idx or 1
  end

  ensure_visible()
  render()
  L('set_query', { query = q, filtered = #S.filtered })
end

---------------------------------------------------------------------
-- Navigation
---------------------------------------------------------------------
local function move_down()
  if #S.filtered == 0 then
    return
  end
  S.user_moved = true
  S.select = clamp(S.select + 1, 1, #S.filtered)
  ensure_visible()
  render()
end

local function move_up()
  if #S.filtered == 0 then
    return
  end
  S.user_moved = true
  S.select = clamp(S.select - 1, 1, #S.filtered)
  ensure_visible()
  render()
end

local function page_down()
  if #S.filtered == 0 then
    return
  end
  S.user_moved = true
  S.select = clamp(S.select + page_rows(), 1, #S.filtered)
  ensure_visible()
  render()
end

local function page_up()
  if #S.filtered == 0 then
    return
  end
  S.user_moved = true
  S.select = clamp(S.select - page_rows(), 1, #S.filtered)
  ensure_visible()
  render()
end

---------------------------------------------------------------------
-- Accept selection
---------------------------------------------------------------------
local function parse_vimgrep(line)
  if type(line) ~= 'string' then
    return nil
  end
  local file, lnum, col = line:match('^(.-):(%d+):(%d+):')
  if not file then
    return nil
  end
  return file, tonumber(lnum) or 1, tonumber(col) or 1
end

local function accept_selection()
  local pick = S.filtered[S.select]
  if type(pick) ~= 'string' or pick == '' or pick:match('^%s*%(') then
    return -- ignore "(no matches)" placeholder
  end

  if S.mode == 'grep' then
    local file, lnum, col = parse_vimgrep(pick)
    if not file then
      return
    end
    local abs = to_abs_path(S.root, file)
    local path = to_display_path(abs)
    M.close()
    vim.schedule(function()
      vim.cmd.edit(vim.fn.fnameescape(path))
      pcall(vim.api.nvim_win_set_cursor, 0, { lnum, col - 1 })
    end)
  else
    local abs = to_abs_path(S.root, pick)
    local path = to_display_path(abs)
    M.close()
    vim.schedule(function()
      vim.cmd.edit(vim.fn.fnameescape(path))
    end)
  end
end

---------------------------------------------------------------------
-- Async backends
---------------------------------------------------------------------
local function cancel_job(job)
  if not job then
    return
  end
  pcall(function()
    job:kill(15)
  end)
end

local function collect_files_async(cb)
  local root = S.root
  local gen = S.gen

  local disk = load_cache(root)
  if disk and type(disk) == 'table' then
    S.files_cached = true
    cb(disk)
    return
  end
  S.files_cached = false

  local file_cmd = M.config.file_cmd
  if not file_cmd then
    if cmd_exists('fd') then
      file_cmd = 'fd'
    elseif cmd_exists('fdfind') then
      file_cmd = 'fdfind'
    end
  end

  if file_cmd and cmd_exists(file_cmd) then
    local args = { file_cmd, '--type', 'f', '--hidden', '--color', 'never' }
    if file_cmd == 'fd' or file_cmd == 'fdfind' then
      table.insert(args, '--strip-cwd-prefix')
      if M.config.follow_symlinks then
        table.insert(args, '-L')
      end
    end
    for _, ex in ipairs(M.config.exclude_patterns or {}) do
      table.insert(args, '--exclude')
      table.insert(args, ex)
    end

    cancel_job(S.job_files)
    S.job_files = vim.system(args, { text = true, cwd = root }, function(obj)
      if not (S.active and gen == S.gen) then
        return
      end
      local list = {}
      if obj.stdout then
        for p in obj.stdout:gmatch('[^\n]+') do
          local rel = normalize_rel(root, p)
          if rel ~= '' then
            list[#list + 1] = rel
          end
        end
      end
      if #list > M.config.max_items then
        local tmp = {}
        for i = 1, M.config.max_items do
          tmp[i] = list[i]
        end
        list = tmp
      end
      save_cache(root, list)
      vim.schedule(function()
        if S.active and gen == S.gen then
          cb(list)
        end
      end)
    end)
    return
  end

  -- Fallback: git ls-files
  if cmd_exists('git') then
    cancel_job(S.job_files)
    S.job_files = vim.system(
      { 'git', 'ls-files', '-co', '--exclude-standard' },
      { text = true, cwd = root },
      function(obj)
        if not (S.active and gen == S.gen) then
          return
        end
        local list = {}
        if obj.stdout then
          for p in obj.stdout:gmatch('[^\n]+') do
            local rel = normalize_rel(root, p)
            if rel ~= '' then
              list[#list + 1] = rel
            end
          end
        end
        if #list > M.config.max_items then
          local tmp = {}
          for i = 1, M.config.max_items do
            tmp[i] = list[i]
          end
          list = tmp
        end
        save_cache(root, list)
        vim.schedule(function()
          if S.active and gen == S.gen then
            cb(list)
          end
        end)
      end
    )
    return
  end

  L('no file lister available')
  cb({})
end

local function grep_async(query, cb)
  if query == '' then
    cb({})
    return
  end
  local gen = S.gen
  local rg = M.config.grep_cmd
  if not cmd_exists(rg) then
    L('grep_cmd not found', rg)
    cb({})
    return
  end

  local root = S.root
  local args = {
    rg,
    '--vimgrep',
    '--hidden',
    '--smart-case',
    '--no-heading',
    '--no-config',
    '--color',
    'never',
    '--path-separator',
    '/',
  }

  for _, p in ipairs(M.config.exclude_patterns or {}) do
    table.insert(args, '--glob')
    table.insert(args, '!' .. p)
  end

  table.insert(args, '--')
  table.insert(args, query)

  cancel_job(S.job_rg)
  S.job_rg = vim.system(args, { text = true, cwd = root }, function(obj)
    if not (S.active and gen == S.gen) then
      return
    end
    local list = {}
    local seen = {} -- track file:line to deduplicate
    if obj.stdout and #obj.stdout > 0 then
      for line in obj.stdout:gmatch('[^\n]+') do
        local file, lnum = line:match('^(.-):(%d+):%d+:')
        if file and lnum then
          local key = file .. ':' .. lnum
          if not seen[key] then
            seen[key] = true
            list[#list + 1] = line
          end
        end
      end
    end
    if #list > M.config.max_items then
      local tmp = {}
      for i = 1, M.config.max_items do
        tmp[i] = list[i]
      end
      list = tmp
    end
    vim.schedule(function()
      if S.active and gen == S.gen then
        cb(list)
      end
    end)
  end)
end

---------------------------------------------------------------------
-- Layout
---------------------------------------------------------------------
local function open_layout(prompt)
  S.buf_inp = vim.api.nvim_create_buf(false, true)
  S.buf_res = vim.api.nvim_create_buf(false, true)

  for _, b in ipairs({ S.buf_inp, S.buf_res }) do
    if b and vim.api.nvim_buf_is_valid(b) then
      vim.bo[b].buflisted = false
      vim.bo[b].bufhidden = 'wipe'
      vim.bo[b].swapfile = false
    end
  end
  vim.bo[S.buf_inp].buftype = 'prompt'
  vim.bo[S.buf_res].buftype = 'nofile'
  vim.bo[S.buf_res].modifiable = false

  local width = math.floor(vim.o.columns * 0.8)
  local height = math.min(math.floor(vim.o.lines * 0.5), M.config.page_size + 2)
  local col = math.floor((vim.o.columns - width) / 2)
  local row = math.floor((vim.o.lines - height) * 0.4)

  S.win_inp = vim.api.nvim_open_win(S.buf_inp, true, {
    relative = 'editor',
    style = 'minimal',
    border = 'rounded',
    width = width,
    height = 1,
    col = col,
    row = row,
    focusable = true,
    zindex = 200,
  })
  vim.fn.prompt_setprompt(S.buf_inp, prompt or '')

  S.win_res = vim.api.nvim_open_win(S.buf_res, false, {
    relative = 'editor',
    style = 'minimal',
    border = 'rounded',
    width = width,
    height = math.max(1, height - 2),
    col = col,
    row = row + 3,
    focusable = false,
    zindex = 199,
  })

  if S.aug then
    pcall(vim.api.nvim_del_augroup_by_id, S.aug)
  end
  S.aug = vim.api.nvim_create_augroup('finder_session', { clear = true })

  vim.api.nvim_create_autocmd('WinEnter', {
    group = S.aug,
    callback = function()
      if not S.active then
        return
      end
      local w = vim.api.nvim_get_current_win()
      if w == S.win_inp or w == S.win_res then
        return
      end
      local cfg = vim.api.nvim_win_get_config(w)
      if cfg and cfg.relative == '' then
        M.close()
      end
    end,
  })

  vim.api.nvim_create_autocmd({ 'BufHidden', 'BufLeave' }, {
    group = S.aug,
    buffer = S.buf_inp,
    callback = function()
      if S.active then
        M.close()
      end
    end,
  })

  vim.api.nvim_create_autocmd('VimResized', {
    group = S.aug,
    callback = function()
      if S.active then
        render()
      end
    end,
  })

  vim.cmd.startinsert()
  L('open_layout')
end

local function close_layout()
  for _, win in ipairs({ S.win_inp, S.win_res }) do
    if win and vim.api.nvim_win_is_valid(win) then
      pcall(vim.api.nvim_win_close, win, true)
    end
  end
  for _, buf in ipairs({ S.buf_inp, S.buf_res }) do
    if buf and vim.api.nvim_buf_is_valid(buf) then
      pcall(vim.api.nvim_buf_delete, buf, { force = true })
    end
  end
  if S.aug then
    pcall(vim.api.nvim_del_augroup_by_id, S.aug)
    S.aug = nil
  end
end

---------------------------------------------------------------------
-- Input handlers
---------------------------------------------------------------------
local function attach_handlers()
  local opts = { buffer = S.buf_inp, nowait = true, silent = true, noremap = true }

  vim.keymap.set('i', '<C-n>', move_down, opts)
  vim.keymap.set('i', '<C-p>', move_up, opts)
  vim.keymap.set('i', '<Down>', move_down, opts)
  vim.keymap.set('i', '<Up>', move_up, opts)
  vim.keymap.set('i', '<C-d>', page_down, opts)
  vim.keymap.set('i', '<C-u>', page_up, opts)
  vim.keymap.set('i', '<CR>', accept_selection, opts)
  vim.keymap.set('i', '<Esc>', M.close, opts)
  vim.keymap.set('i', '<C-c>', M.close, opts)

  vim.api.nvim_create_autocmd({ 'TextChangedI', 'TextChangedP' }, {
    group = S.aug,
    buffer = S.buf_inp,
    callback = function()
      local delay = effective_debounce_ms()
      debounce(function()
        if not (S.active and S.buf_inp and vim.api.nvim_buf_is_valid(S.buf_inp)) then
          return
        end
        local raw = vim.fn.getline('.') or ''
        local prompt_len = S.mode == 'files' and 8 or 6 -- "Search: " or "Grep: "
        local q = raw:sub(prompt_len + 1)

        if S.mode == 'grep' then
          grep_async(q, function(list)
            if not S.active then
              return
            end
            S.items = list or {}
            set_query(q)
          end)
        else
          set_query(q)
        end
      end, delay)
    end,
  })

  L('handlers attached')
end

---------------------------------------------------------------------
-- Public API
---------------------------------------------------------------------
function M.files()
  if S.active then
    M.close()
  end
  S.active = true
  S.gen = S.gen + 1
  S.user_moved = false
  S.mode = 'files'
  S.root = project_root()
  open_layout('Search: ')
  attach_handlers()
  collect_files_async(function(list)
    if not S.active then
      return
    end
    set_items(list)
  end)
end

function M.grep()
  if S.active then
    M.close()
  end
  S.active = true
  S.gen = S.gen + 1
  S.user_moved = false
  S.mode = 'grep'
  S.root = project_root()
  open_layout('Grep: ')
  attach_handlers()
  S.items = {}
  set_query('')
end

function M.close()
  if not S.active then
    return
  end
  if S.timer then
    pcall(function()
      S.timer:stop()
      S.timer:close()
    end)
    S.timer = nil
  end
  cancel_job(S.job_rg)
  S.job_rg = nil
  cancel_job(S.job_files)
  S.job_files = nil

  close_layout()
  S.active = false
  S.mode, S.root = nil, nil
  S.items, S.filtered, S.positions = {}, {}, {}
  S.query, S.select, S.scroll = '', 1, 0
  S.user_moved = false
  S.files_cached = false
  L('closed')
end

function M.clear_cache()
  local root = project_root()
  local file = root .. '/.devflow/finder_cache.json'
  local ok = pcall(os.remove, file)
  vim.notify(ok and 'Finder cache cleared' or 'No cache to clear')
end

function M.diagnose()
  local root = project_root()
  local lines = { '=== Finder Diagnostics ===' }

  local fd_cmd = M.config.file_cmd
    or (cmd_exists('fd') and 'fd')
    or (cmd_exists('fdfind') and 'fdfind')
    or nil
  table.insert(lines, 'fd command: ' .. tostring(fd_cmd))
  table.insert(
    lines,
    'rg command: '
      .. tostring(M.config.grep_cmd)
      .. ' (exists: '
      .. tostring(cmd_exists(M.config.grep_cmd))
      .. ')'
  )

  local cache_file = root .. '/.devflow/finder_cache.json'
  local cache_stat = vim.loop.fs_stat(cache_file)
  if cache_stat then
    table.insert(lines, 'Cache file: ' .. cache_file)
    table.insert(lines, 'Cache size: ' .. cache_stat.size .. ' bytes')
    local cached = load_cache(root)
    if cached then
      table.insert(lines, 'Cache valid: true (' .. #cached .. ' files)')
    else
      table.insert(lines, 'Cache valid: false (expired or corrupt)')
    end
  else
    table.insert(lines, 'Cache: none')
  end

  table.insert(lines, 'Exclude patterns: ' .. vim.inspect(M.config.exclude_patterns))
  table.insert(lines, 'Follow symlinks: ' .. tostring(M.config.follow_symlinks))

  vim.notify(table.concat(lines, '\n'), vim.log.levels.INFO)
end

function M.setup(opts)
  M.config = vim.tbl_deep_extend('force', M.config, opts or {})

  local fd_cmd = M.config.file_cmd
  if fd_cmd and not cmd_exists(fd_cmd) then
    vim.notify('[finder] file_cmd "' .. fd_cmd .. '" not found', vim.log.levels.WARN)
  end
  if M.config.grep_cmd and not cmd_exists(M.config.grep_cmd) then
    vim.notify('[finder] grep_cmd "' .. M.config.grep_cmd .. '" not found', vim.log.levels.WARN)
  end

  L('setup complete', M.config)
end

return M