--- @since 25.5.28

local M = {}

local STATE_KEY = {
  ALTER_DF_COMMAND = "ALTER_DF_COMMAND",
}

local set_state = ya.sync(function(state, key, value)
  state[key] = value
end)

local get_state = ya.sync(function(state, key)
  return state[key]
end)

local function permission(file)
  local h = file
  if not h then
    return ""
  end

  local perm = h.cha:perm()
  if not perm then
    return ""
  end

  local spans = ""
  for i = 1, #perm do
    local c = perm:sub(i, i)
    spans = spans .. c
  end
  return spans
end

local function link_count(file)
  local h = file
  if h == nil or ya.target_family() ~= "unix" then
    return ""
  end

  return h.cha.nlink
end

local function owner_group(file)
  local h = file
  if h == nil or ya.target_family() ~= "unix" then
    return ""
  end
  return (ya.user_name(h.cha.uid) or tostring(h.cha.uid)) .. "/" .. (ya.group_name(h.cha.gid) or tostring(h.cha.gid))
end

local file_size_and_folder_childs = function(file)
  local h = file
  if not h then
    return ""
  end

  return h.cha.len and ya.readable_size(h.cha.len) or ""
end

--- get file timestamp
---@param file any
---@param type "mtime" | "atime" | "btime"
---@return any
local function fileTimestamp(file, type)
  local h = file
  if not h then
    return ""
  end
  local time = math.floor(h.cha[type] or 0)
  if time == 0 then
    return ""
  else
    return os.date("%Y-%m-%d %H:%M", time)
  end
end

-- Function to split a string by spaces (considering multiple spaces as one delimiter)
local function split_by_whitespace(input)
  local result = {}
  for word in string.gmatch(input, "%S+") do
    table.insert(result, word)
  end
  return result
end

local function get_filesystem_extra(file)
  local result = {
    filesystem = "",
    device = "",
    type = "",
    used_space = "",
    avail_space = "",
    total_space = "",
    used_space_percent = "",
    avail_space_percent = "",
    error = nil,
    is_virtual = false,
  }
  local h = file
  local file_url = h.url
  local is_virtual = file_url.spec and file_url.scheme.is_virtual
  file_url = is_virtual and (file.path or Url(file_url.scheme.cache .. tostring(file_url.path)))
    or (file_url.path or file_url.url)
  if not h or ya.target_family() ~= "unix" then
    return result
  end
  local output, child

  local alter_df_command = get_state(STATE_KEY.ALTER_DF_COMMAND)
  if not alter_df_command then
    child, _ = Command("df"):arg({ "-P", "-T", "-h", tostring(file_url) }):stdout(Command.PIPED):spawn()

    if child then
      -- Ignore header
      local _, event = child:read_line()
      if event == 0 then
        output, _ = child:read_line()
      end
      child:start_kill()
    end
  end

  -- Fallback for macOS/BSD if -T failed (empty output or error)
  if not output or output == "" then
    if not alter_df_command then
      set_state(STATE_KEY.ALTER_DF_COMMAND, true)
    end
    child, _ = Command("df"):arg({ "-P", "-h", tostring(file_url) }):stdout(Command.PIPED):spawn()
    if child then
      local _, event = child:read_line() -- skip header
      if event == 0 then
        output, _ = child:read_line()
      end
      child:start_kill()
    end
  end

  if output and output ~= "" then
    -- Splitting the data
    local parts = split_by_whitespace(output)

    -- Display the result
    if #parts >= 7 then
      result.filesystem = is_virtual and (parts[7] .. " (vfs)") or parts[7]
      result.device = is_virtual and (parts[1] .. " (vfs)") or parts[1]
      result.total_space = parts[3]
      result.used_space = parts[4]
      result.avail_space = parts[5]
      result.used_space_percent = parts[6]
      result.avail_space_percent = 100 - tonumber((string.match(parts[6], "%d+") or "0"))
      result.type = is_virtual and (parts[2] .. " (vfs)") or parts[2]
    else
      result.filesystem = is_virtual and (parts[6] .. " (vfs)") or parts[6]
      -- result.device (Type) is missing in df output, fetch from mount
      result.total_space = parts[2]
      result.used_space = parts[3]
      result.avail_space = parts[4]
      result.used_space_percent = parts[5]
      result.avail_space_percent = 100 - tonumber((string.match(parts[5], "%d+") or "0"))
      result.device = is_virtual and (parts[1] .. " (vfs)") or parts[1]

      local mount_child = Command("mount"):stdout(Command.PIPED):spawn()
      if mount_child then
        while true do
          local line, event = mount_child:read_line()
          if not line or event ~= 0 then
            break
          end
          -- Check if line starts with filesystem (e.g. /dev/disk1s1 on ...)
          local s, e = line:find(parts[1] .. " on ", 1, true)
          if s == 1 then
            local fstype = line:match("%(([^,]+)")
            if fstype then
              result.type = is_virtual and (fstype .. " (vfs)") or fstype
            end
            break
          end
        end
      end
    end
    result.is_virtual = is_virtual
  else
    result.error = "df error: check install"
  end
  return result
end

local function attributes(file)
  local h = file
  local file_url = h.url
  if h.cha.is_link then
    file_url = Url(h.link_to)
  end
  local is_virtual = file_url.scheme and file_url.scheme.is_virtual
  file_url = is_virtual and (file.path or Url(file_url.scheme.cache .. tostring(file_url.path))) or file_url

  if not h or ya.target_family() ~= "unix" then
    return ""
  end

  local output, _ = Command("lsattr"):arg({ "-d", tostring(file_url) }):stdout(Command.PIPED):output()

  if output then
    -- Splitting the data
    local parts = split_by_whitespace(output.stdout)

    -- Display the result
    for i, part in ipairs(parts) do
      if i == 1 then
        return part
      end
    end
    return ""
  else
    return "lsattr error: check install"
  end
end

---shorten string
---@param _s string string
---@param _t string tail
---@param _w number max characters
---@return string
local shorten = function(_s, _t, _w)
  local s = _s or utf8.len(_s)
  local t = _t or ""
  local ellipsis = "…" .. t
  local w = _w < utf8.len(ellipsis) and utf8.len(ellipsis) or _w
  local n_ellipsis = utf8.len(ellipsis) or 0
  if utf8.len(s) > w then
    return s:sub(1, (utf8.offset(s, w - n_ellipsis + 1) or 2) - 1) .. ellipsis
  end
  return s
end

function M:render_table(job, opts)
  local styles = {
    header = th.spot.title or ui.Style():fg("green"),
    row_label = ui.Style():fg("reset"),
    row_value = th.spot.tbl_col or ui.Style():fg("blue"),
  }
  local filesystem_extra = get_filesystem_extra(job.file)
  local prefix = "  "
  local rows = {}
  local label_max_length = 15
  local file_name_extension = job.file.cha.is_dir and "…" or ("." .. (job.file.url.ext or ""))

  local row = function(key, value)
    local h = type(value) == "table" and #value or 1
    rows[#rows + 1] = ui.Row({ ui.Line(key):style(styles.row_label), ui.Text(value):style(styles.row_value) }):height(h)
  end

  local file_name = shorten(
    job.file.name,
    file_name_extension,
    math.floor(job.area.w - label_max_length - utf8.len(file_name_extension))
  )
  local location = shorten(
    tostring((job.file.url.path or job.file.url).parent),
    "",
    math.floor(job.area.w - label_max_length - utf8.len(prefix))
  )
  local filesystem_error = filesystem_extra.error
      and shorten(filesystem_extra.error, "", math.floor(job.area.w - label_max_length - utf8.len(prefix)))
    or nil
  local filesystem =
    shorten(filesystem_extra.filesystem, "", math.floor(job.area.w - label_max_length - utf8.len(prefix)))

  rows[#rows + 1] = ui.Row({ "Metadata", "" }):style(styles.header)
  row(prefix .. "File:", file_name)
  row(prefix .. "Mimetype:", job.mime)
  row(prefix .. "Location:", location)
  if job.file.cache then
    row(prefix .. "Cached:", tostring(job.file.path or job.file.cache))
  end
  row(prefix .. "Mode:", permission(job.file))
  row(prefix .. "Attributes:", attributes(job.file))
  row(prefix .. "Links:", tostring(link_count(job.file)))
  if job.file.cha.is_link then
    row(prefix .. "Linked:", tostring(job.file.cha.is_link and job.file.link_to))
  end
  row(prefix .. "Owner:", owner_group(job.file))
  row(prefix .. "Size:", file_size_and_folder_childs(job.file))
  row(prefix .. "Created:", fileTimestamp(job.file, "btime"))
  row(prefix .. "Modified:", fileTimestamp(job.file, "mtime"))
  row(prefix .. "Accessed:", fileTimestamp(job.file, "atime"))
  row(prefix .. "Filesystem:", filesystem_error or filesystem)
  row(prefix .. "Device:", filesystem_error or filesystem_extra.device)
  row(prefix .. "Type:", filesystem_error or filesystem_extra.type)
  row(
    prefix .. "Free space:",
    filesystem_error
      or (
        (filesystem_extra.avail_space and filesystem_extra.total_space and filesystem_extra.avail_space_percent)
          and (filesystem_extra.avail_space .. " / " .. filesystem_extra.total_space .. " (" .. filesystem_extra.avail_space_percent .. "%)")
        or ""
      )
  )
  if opts and opts.show_plugins_section then
    -- TODO: Remove this after the next release
    local is_yazi_nightly, _ = pcall(require, "mime.dir")
    local spotter = rt.plugin.spotter(is_yazi_nightly and job.file or job.file.url, job.mime)
    local previewer = rt.plugin.previewer(is_yazi_nightly and job.file or job.file.url, job.mime)
    local fetchers = rt.plugin.fetchers(job.file, job.mime)
    local preloaders = rt.plugin.preloaders(is_yazi_nightly and job.file or job.file.url, job.mime)

    for i, v in ipairs(fetchers) do
      fetchers[i] = v.cmd
    end
    for i, v in ipairs(preloaders) do
      preloaders[i] = v.cmd
    end

    rows[#rows + 1] = ui.Row({ { "", "Plugins" }, "" }):height(2):style(styles.header)
    row(prefix .. "Spotter:", spotter and spotter.cmd or "(none)")
    row(prefix .. "Previewer:", previewer and previewer.cmd or "(none)")
    row(prefix .. "Fetchers:", #fetchers ~= 0 and fetchers or "(none)")
    row(prefix .. "Preloaders:", #preloaders ~= 0 and preloaders or "(none)")
  end

  return ui.Table(rows):area(job.area):row(1):col(1):col_style(styles.row_value):widths({
    ui.Constraint.Length(label_max_length),
    ui.Constraint.Fill(1),
  })
end

function M:peek(job)
  local start, cache = os.clock(), ya.file_cache(job)
  if not cache or not self:preload(job) then
    return 1
  end
  ya.sleep(math.max(0, rt.preview.image_delay / 1000 + start - os.clock()))
  ya.preview_widget(job, { self:render_table(job) })
end

function M:seek(job)
  local h = cx.active.current.hovered
  if h and h.url == job.file.url then
    local step = math.floor(job.units * job.area.h / 10)
    ya.emit("peek", {
      tostring(math.max(0, cx.active.preview.skip + step)),
      only_if = tostring(job.file.url),
    })
  end
end

function M:preload(job)
  local cache = ya.file_cache(job)
  if not cache or fs.cha(cache) then
    return true
  end
  return true
end

function M:spot(job)
  job.area = ui.Pos({ "center", w = 80, h = 25 })
  ya.spot_table(
    job,
    self
      :render_table(job, { show_plugins_section = true })
      :cell_style(th.spot.tbl_cell or ui.Style():fg("blue"):reverse())
  )
end

return M