-- mod-version:2 -- lite-xl 2.0
local core = require "core"
local common = require "core.common"
local command = require "core.command"
local config = require "core.config"
local keymap = require "core.keymap"
local style = require "core.style"
local View = require "core.view"
local ContextMenu = require "core.contextmenu"
local RootView = require "core.rootview"


local default_treeview_size = 200 * SCALE
local tooltip_offset = style.font:get_height()
local tooltip_border = 1
local tooltip_delay = 0.5
local tooltip_alpha = 255
local tooltip_alpha_rate = 1


local function get_depth(filename)
  local n = 1
  for sep in filename:gmatch("[\\/]") do
    n = n + 1
  end
  return n
end

local function replace_alpha(color, alpha)
  local r, g, b = table.unpack(color)
  return { r, g, b, alpha }
end


local TreeView = View:extend()

function TreeView:new()
  TreeView.super.new(self)
  self.scrollable = true
  self.visible = true
  self.init_size = true
  self.target_size = default_treeview_size
  self.cache = {}
  self.last = {}
  self.tooltip = { x = 0, y = 0, begin = 0, alpha = 0 }
end


function TreeView:set_target_size(axis, value)
  if axis == "x" then
    self.target_size = value
    return true
  end
end


function TreeView:get_cached(item, dirname)
  local dir_cache = self.cache[dirname]
  if not dir_cache then
    dir_cache = {}
    self.cache[dirname] = dir_cache
  end
  -- to discriminate top directories from regular files or subdirectories
  -- we add ':' at the end of the top directories' filename. it will be
  -- used only to identify the entry into the cache.
  local cache_name = item.filename .. (item.topdir and ":" or "")
  local t = dir_cache[cache_name]
  if not t then
    t = {}
    local basename = common.basename(item.filename)
    if item.topdir then
      t.filename = basename
      t.expanded = true
      t.depth = 0
      t.abs_filename = dirname
    else
      t.filename = item.filename
      t.depth = get_depth(item.filename)
      t.abs_filename = dirname .. PATHSEP .. item.filename
    end
    t.name = basename
    t.type = item.type
    dir_cache[cache_name] = t
  end
  return t
end


function TreeView:get_name()
  return "Project"
end


function TreeView:get_item_height()
  return style.font:get_height() + style.padding.y
end


function TreeView:invalidate_cache(dirname)
  for _, v in pairs(self.cache[dirname]) do
    v.skip = nil
  end
end


function TreeView:check_cache()
  -- invalidate cache's skip values if project_files has changed
  for i = 1, #core.project_directories do
    local dir = core.project_directories[i]
    local last_files = self.last[dir.name]
    if not last_files then
      self.last[dir.name] = dir.files
    else
      if dir.files ~= last_files then
        self:invalidate_cache(dir.name)
        self.last[dir.name] = dir.files
      end
    end
  end
end


function TreeView:each_item()
  return coroutine.wrap(function()
    self:check_cache()
    local count_lines = 0
    local ox, oy = self:get_content_offset()
    local y = oy + style.padding.y
    local w = self.size.x
    local h = self:get_item_height()

    for k = 1, #core.project_directories do
      local dir = core.project_directories[k]
      local dir_cached = self:get_cached(dir.item, dir.name)
      coroutine.yield(dir_cached, ox, y, w, h)
      count_lines = count_lines + 1
      y = y + h
      local i = 1
      while i <= #dir.files and dir_cached.expanded do
        local item = dir.files[i]
        local cached = self:get_cached(item, dir.name)

        coroutine.yield(cached, ox, y, w, h)
        count_lines = count_lines + 1
        y = y + h
        i = i + 1

        if not cached.expanded then
          if cached.skip then
            i = cached.skip
          else
            local depth = cached.depth
            while i <= #dir.files do
              if get_depth(dir.files[i].filename) <= depth then break end
              i = i + 1
            end
            cached.skip = i
          end
        end
      end -- while files
    end -- for directories
    self.count_lines = count_lines
  end)
end


function TreeView:get_text_bounding_box(item, x, y, w, h)
  local icon_width = style.icon_font:get_width("D")
  local xoffset = item.depth * style.padding.x + style.padding.x + icon_width
  x = x + xoffset
  w = style.font:get_width(item.name) + 2 * style.padding.x
  return x, y, w, h
end


function TreeView:on_mouse_moved(px, py, ...)
  TreeView.super.on_mouse_moved(self, px, py, ...)
  if self.dragging_scrollbar then return end

  local item_changed, tooltip_changed
  for item, x,y,w,h in self:each_item() do
    if px > x and py > y and px <= x + w and py <= y + h then
      item_changed = true
      self.hovered_item = item

      x,y,w,h = self:get_text_bounding_box(item, x,y,w,h)
      if px > x and py > y and px <= x + w and py <= y + h then
        tooltip_changed = true
        self.tooltip.x, self.tooltip.y = px, py
        self.tooltip.begin = system.get_time()
      end
      break
    end
  end
  if not item_changed then self.hovered_item = nil end
  if not tooltip_changed then self.tooltip.x, self.tooltip.y = nil, nil end
end


local function create_directory_in(item)
  local path = item.abs_filename
  core.command_view:enter("Create directory in " .. path, function(text)
    local dirname = path .. PATHSEP .. text
    local success, err = system.mkdir(dirname)
    if not success then
      core.error("cannot create directory %q: %s", dirname, err)
    end
    item.expanded = true
    core.reschedule_project_scan()
  end)
end


function TreeView:on_mouse_pressed(button, x, y, clicks)
  local caught = TreeView.super.on_mouse_pressed(self, button, x, y, clicks)
  if caught or button ~= "left" then
    return
  end
  local hovered_item = self.hovered_item
  if not hovered_item then
    return
  elseif hovered_item.type == "dir" then
    if keymap.modkeys["ctrl"] and button == "left" then
      create_directory_in(hovered_item)
    else
      if core.project_files_limit and not hovered_item.expanded then
        local filename, abs_filename = hovered_item.filename, hovered_item.abs_filename
        local index = 0
        -- The loop below is used to find the first match starting from the end
        -- in case there are multiple matches.
        while index and index + #filename < #abs_filename do
          index = string.find(abs_filename, filename, index + 1, true)
        end
        -- we assume here index is not nil because the abs_filename must contain the
        -- relative filename
        local dirname = string.sub(abs_filename, 1, index - 2)
        if core.is_project_folder(dirname) then
          core.scan_project_folder(dirname, filename)
          self:invalidate_cache(dirname)
        end
      end
      hovered_item.expanded = not hovered_item.expanded
    end
  else
    core.try(function()
      local doc_filename = common.relative_path(core.project_dir, hovered_item.abs_filename)
      core.root_view:open_doc(core.open_doc(doc_filename))
    end)
  end
end


function TreeView:update()
  -- update width
  local dest = self.visible and self.target_size or 0
  if self.init_size then
    self.size.x = dest
    self.init_size = false
  else
    self:move_towards(self.size, "x", dest)
  end

  local duration = system.get_time() - self.tooltip.begin
  if self.hovered_item and self.tooltip.x and duration > tooltip_delay then
    self:move_towards(self.tooltip, "alpha", tooltip_alpha, tooltip_alpha_rate)
  else
    self.tooltip.alpha = 0
  end

  TreeView.super.update(self)
end


function TreeView:get_scrollable_size()
  return self.count_lines and self:get_item_height() * (self.count_lines + 1) or math.huge
end


function TreeView:draw_tooltip()
  local text = common.home_encode(self.hovered_item.abs_filename)
  local w, h = style.font:get_width(text), style.font:get_height(text)

  local x, y = self.tooltip.x + tooltip_offset, self.tooltip.y + tooltip_offset
  w, h = w + style.padding.x, h + style.padding.y

  if x + w > core.root_view.root_node.size.x then -- check if we can span right
    x = x - w -- span left instead
  end

  local bx, by = x - tooltip_border, y - tooltip_border
  local bw, bh = w + 2 * tooltip_border, h + 2 * tooltip_border
  renderer.draw_rect(bx, by, bw, bh, replace_alpha(style.text, self.tooltip.alpha))
  renderer.draw_rect(x, y, w, h, replace_alpha(style.background2, self.tooltip.alpha))
  common.draw_text(style.font, replace_alpha(style.text, self.tooltip.alpha), text, "center", x, y, w, h)
end


function TreeView:draw()
  self:draw_background(style.background2)

  local icon_width = style.icon_font:get_width("D")
  local spacing = style.icon_font:get_width("f") / 2

  local doc = core.active_view.doc
  local active_filename = doc and system.absolute_path(doc.filename or "")

  for item, x,y,w,h in self:each_item() do
    local color = style.text

    -- highlight active_view doc
    if item.abs_filename == active_filename then
      color = style.accent
    end

    -- hovered item background
    if item == self.hovered_item then
      renderer.draw_rect(x, y, w, h, style.line_highlight)
      color = style.accent
    end

    -- icons
    x = x + item.depth * style.padding.x + style.padding.x
    if item.type == "dir" then
      local icon1 = item.expanded and "-" or "+"
      local icon2 = item.expanded and "D" or "d"
      common.draw_text(style.icon_font, color, icon1, nil, x, y, 0, h)
      x = x + style.padding.x
      common.draw_text(style.icon_font, color, icon2, nil, x, y, 0, h)
      x = x + icon_width
    else
      x = x + style.padding.x
      common.draw_text(style.icon_font, color, "f", nil, x, y, 0, h)
      x = x + icon_width
    end

    -- text
    x = x + spacing
    x = common.draw_text(style.font, color, item.name, nil, x, y, 0, h)
  end

  self:draw_scrollbar()
  if self.hovered_item and self.tooltip.alpha > 0 then
    core.root_view:defer_draw(self.draw_tooltip, self)
  end
end


-- init
local view = TreeView()
local node = core.root_view:get_active_node()
local treeview_node = node:split("left", view, {x = true}, true)

-- The toolbarview plugin is special because it is plugged inside
-- a treeview pane which is itelf provided in a plugin.
-- We therefore break the usual plugin's logic that would require each
-- plugin to be independent of each other. In addition it is not the
-- plugin module that plug itself in the active node but it is plugged here
-- in the treeview node.
local toolbar_view = nil
local toolbar_plugin, ToolbarView = core.try(require, "plugins.toolbarview")
if config.plugins.toolbarview ~= false and toolbar_plugin then
  toolbar_view = ToolbarView()
  treeview_node:split("down", toolbar_view, {y = true})
  local min_toolbar_width = toolbar_view:get_min_width()
  view:set_target_size("x", math.max(default_treeview_size, min_toolbar_width))
  command.add(nil, {
    ["toolbar:toggle"] = function()
      toolbar_view:toggle_visible()
    end,
  })
end

-- Add a context menu to the treeview
local menu = ContextMenu()

local on_view_mouse_pressed = RootView.on_view_mouse_pressed
local on_mouse_moved = RootView.on_mouse_moved
local root_view_update = RootView.update
local root_view_draw = RootView.draw

function RootView:on_mouse_moved(...)
  if menu:on_mouse_moved(...) then return end
  on_mouse_moved(self, ...)
end

function RootView.on_view_mouse_pressed(button, x, y, clicks)
  -- We give the priority to the menu to process mouse pressed events.
  if button == "right" then
    view.tooltip.alpha = 0
    view.tooltip.x, view.tooltip.y = nil, nil
  end
  local handled = menu:on_mouse_pressed(button, x, y, clicks)
  return handled or on_view_mouse_pressed(button, x, y, clicks)
end

function RootView:update(...)
  root_view_update(self, ...)
  menu:update()
end

function RootView:draw(...)
  root_view_draw(self, ...)
  menu:draw()
end

local function is_project_folder(path)
  return common.basename(core.project_dir) == path
end

menu:register(function() return view.hovered_item end, {
  { text = "Open in System", command = "treeview:open-in-system" },
  ContextMenu.DIVIDER
})

menu:register(
  function()
    return view.hovered_item
      and not is_project_folder(view.hovered_item.filename)
  end,
  {
    { text = "Rename", command = "treeview:rename" },
    { text = "Delete", command = "treeview:delete" },
  }
)

menu:register(
  function()
    return view.hovered_item and view.hovered_item.type == "dir"
  end,
  {
    { text = "New File", command = "treeview:new-file" },
    { text = "New Folder", command = "treeview:new-folder" },
  }
)

-- Register the TreeView commands and keymap
command.add(nil, {
  ["treeview:toggle"] = function()
    view.visible = not view.visible
  end})


command.add(function() return view.hovered_item ~= nil end, {
  ["treeview:rename"] = function()
    local old_filename = view.hovered_item.filename
    local old_abs_filename = view.hovered_item.abs_filename
    core.command_view:set_text(old_filename)
    core.command_view:enter("Rename", function(filename)
      filename = core.normalize_to_project_dir(filename)
      local abs_filename = core.project_absolute_path(filename)
      local res, err = os.rename(old_abs_filename, abs_filename)
      if res then -- successfully renamed
        for _, doc in ipairs(core.docs) do
          if doc.abs_filename and old_abs_filename == doc.abs_filename then
            doc:set_filename(filename, abs_filename) -- make doc point to the new filename
            doc:reset_syntax()
            break -- only first needed
          end
        end
        core.log("Renamed \"%s\" to \"%s\"", old_filename, filename)
      else
        core.error("Error while renaming \"%s\" to \"%s\": %s", old_abs_filename, abs_filename, err)
      end
      core.reschedule_project_scan()
    end, common.path_suggest)
  end,

  ["treeview:new-file"] = function()
    local dir_name = view.hovered_item.filename
    if not is_project_folder(dir_name) then
      core.command_view:set_text(dir_name .. "/")
    end
    core.command_view:enter("Filename", function(filename)
      local doc_filename = core.project_dir .. PATHSEP .. filename
      local file = io.open(doc_filename, "a+")
      file:write("")
      file:close()
      core.root_view:open_doc(core.open_doc(doc_filename))
      core.reschedule_project_scan()
      core.log("Created %s", doc_filename)
    end, common.path_suggest)
  end,

  ["treeview:new-folder"] = function()
    local dir_name = view.hovered_item.filename
    if not is_project_folder(dir_name) then
      core.command_view:set_text(dir_name .. "/")
    end
    core.command_view:enter("Folder Name", function(filename)
      local dir_path = core.project_dir .. PATHSEP .. filename
      common.mkdirp(dir_path)
      core.reschedule_project_scan()
      core.log("Created %s", dir_path)
    end, common.path_suggest)
  end,

  ["treeview:delete"] = function()
    local filename = view.hovered_item.abs_filename
    local relfilename = view.hovered_item.filename
    local file_info = system.get_file_info(filename)
    local file_type = file_info.type == "dir" and "Directory" or "File"
    -- Ask before deleting
    local opt = {
      { font = style.font, text = "Yes", default_yes = true },
      { font = style.font, text = "No" , default_no = true }
    }
    core.nag_view:show(
      string.format("Delete %s", file_type),
      string.format(
        "Are you sure you want to delete the %s?\n%s: %s",
        file_type:lower(), file_type, relfilename
      ),
      opt,
      function(item)
        if item.text == "Yes" then
          if file_info.type == "dir" then
            local deleted, error, path = common.rm(filename, true)
            if not deleted then
              core.error("Error: %s - \"%s\" ", error, path)
              return
            end
          else
            local removed, error = os.remove(filename)
            if not removed then
              core.error("Error: %s - \"%s\"", error, filename)
              return
            end
          end
          core.reschedule_project_scan()
          core.log("Deleted \"%s\"", filename)
        end
      end
    )
  end,

  ["treeview:open-in-system"] = function()
    local hovered_item = view.hovered_item

    if PLATFORM == "Windows" then
      system.exec(string.format("start \"\" %q", hovered_item.abs_filename))
    elseif string.find(PLATFORM, "Mac") then
      system.exec(string.format("open %q", hovered_item.abs_filename))
    elseif PLATFORM == "Linux" then
      system.exec(string.format("xdg-open %q", hovered_item.abs_filename))
    end
  end,
})

keymap.add { ["ctrl+\\"] = "treeview:toggle" }

-- Return the treeview with toolbar and contextmenu to allow
-- user or plugin modifications
view.toolbar = toolbar_view
view.contextmenu = menu

return view