-- This module is responsible for the discussion tree. That includes things like
-- editing existing notes in the tree, replying to notes in the tree,
-- and marking discussions as resolved/unresolved.
local Popup        = require("nui.popup")
local Menu         = require("nui.menu")
local NuiTree      = require("nui.tree")
local NuiSplit     = require("nui.split")
local job          = require("gitlab.job")
local u            = require("gitlab.utils")
local state        = require("gitlab.state")
local reviewer     = require("gitlab.reviewer")

local edit_popup   = Popup(u.create_popup_state("Edit Comment", "80%", "80%"))
local reply_popup  = Popup(u.create_popup_state("Reply", "80%", "80%"))

local M            = {
  split_visible = false,
  split = nil,
  split_buf = nil,
  tree = nil
}

M.set_tree_keymaps = function()
  vim.keymap.set('n', state.settings.discussion_tree.jump_to_file, M.jump_to_file, { buffer = true })
  vim.keymap.set('n', state.settings.discussion_tree.jump_to_reviewer, M.jump_to_reviewer, { buffer = true })
  vim.keymap.set('n', state.settings.discussion_tree.edit_comment, M.edit_comment, { buffer = true })
  vim.keymap.set('n', state.settings.discussion_tree.delete_comment, M.delete_comment, { buffer = true })
  vim.keymap.set('n', state.settings.discussion_tree.toggle_resolved, M.toggle_resolved, { buffer = true })
  vim.keymap.set('n', state.settings.discussion_tree.toggle_node, M.toggle_node, { buffer = true })
  vim.keymap.set('n', state.settings.discussion_tree.reply, M.reply, { buffer = true })
end

-- Opens the discussion tree, sets the keybindings,
M.toggle           = function()
  if M.split_visible then
    M.split:hide()
    M.split_visible = false
    return
  end

  if M.split then
    M.split:show()
    M.split_visible = true
    return
  end

  local split = NuiSplit({
    buf_options = { modifiable = false },
    relative = state.settings.discussion_tree.relative,
    position = state.settings.discussion_tree.position,
    size = state.settings.discussion_tree.size,
  })

  split:mount()
  M.split = split
  M.split_visible = true
  M.split_buf = split.bufnr
  state.discussion_buf = split.bufnr

  vim.api.nvim_create_autocmd({ "QuitPre", "BufDelete", "BufUnload" }, {
    buffer = split.bufnr,
    callback = function()
      M.split = nil
      M.split_visible = false
      M.split_buf = nil
    end,
    desc = "Handles users who close the split in non-keybinding fashion",
  })

  local buf = M.split.bufnr

  job.run_job("/discussions", "GET", nil, function(data)
    if type(data.discussions) ~= "table" then
      vim.notify("No discussions for this MR", vim.log.levels.WARN)
      return
    end

    local tree_nodes = M.add_discussions_to_table(data.discussions)

    M.tree = NuiTree({ nodes = tree_nodes, bufnr = buf })
    M.set_tree_keymaps()

    M.tree:render()
    vim.api.nvim_buf_set_option(buf, 'filetype', 'markdown')
  end)
end

-- The reply popup will mount in a window when you trigger it (settings.discussion_tree.reply) when hovering over a node in the discussion tree.
M.reply            = function()
  local node = M.tree:get_node()
  local discussion_node = M.get_root_node(node)
  local id = tostring(discussion_node.id)
  reply_popup:mount()
  state.set_popup_keymaps(reply_popup, M.send_reply(id))
end

-- This function will send the reply to the Go API
M.send_reply       = function(discussion_id)
  print(discussion_id)
  return function(text)
    local jsonTable = { discussion_id = discussion_id, reply = text }
    local json = vim.json.encode(jsonTable)
    job.run_job("/reply", "POST", json, function(data)
      M.add_note_to_tree(data.note, discussion_id)
    end)
  end
end

-- This function (settings.discussion_tree.delete_comment) will trigger a popup prompting you to delete the current comment
M.delete_comment   = function()
  local menu = Menu({
    position = "50%",
    size = {
      width = 25,
    },
    border = {
      style = "single",
      text = {
        top = "Delete Comment?",
        top_align = "center",
      },
    },
    win_options = {
      winhighlight = "Normal:Normal,FloatBorder:Normal",
    },
  }, {
    lines = {
      Menu.item("Confirm"),
      Menu.item("Cancel"),
    },
    max_width = 20,
    keymap = {
      focus_next = state.settings.dialogue.focus_next,
      focus_prev = state.settings.dialogue.focus_prev,
      close = state.settings.dialogue.close,
      submit = state.settings.dialogue.submit,
    },
    on_submit = M.send_deletion
  })
  menu:mount()
end

-- This function will actually send the deletion to Gitlab
-- when you make a selection
M.send_deletion    = function(item)
  if item.text == "Confirm" then
    local current_node = M.tree:get_node()

    local note_node = M.get_note_node(current_node)
    local root_node = M.get_root_node(current_node)
    local note_id = note_node.is_root and root_node.root_note_id or note_node.id

    local jsonTable = { discussion_id = root_node.id, note_id = note_id }
    local json = vim.json.encode(jsonTable)

    job.run_job("/comment", "DELETE", json, function(data)
      vim.notify(data.message, vim.log.levels.INFO)
      if not note_node.is_root then
        M.tree:remove_node("-" .. note_id)
        M.tree:render()
      else
        -- We are removing the root node of the discussion,
        -- we need to move all the children around, the easiest way
        -- to do this is to just re-render the whole tree 🤷
        M.refresh_tree()
        note_node:expand()
      end
    end)
  end
end

-- This function (settings.discussion_tree.edit_comment) will open the edit popup for the current comment in the discussion tree
M.edit_comment     = function()
  local current_node = M.tree:get_node()
  local note_node = M.get_note_node(current_node)
  local root_node = M.get_root_node(current_node)

  edit_popup:mount()

  local lines = {} -- Gather all lines from immediate children that aren't note nodes
  local children_ids = note_node:get_child_ids()
  for _, child_id in ipairs(children_ids) do
    local child_node = M.tree:get_node(child_id)
    if (not child_node:has_children()) then
      local line = M.tree:get_node(child_id).text
      table.insert(lines, line)
    end
  end

  local currentBuffer = vim.api.nvim_get_current_buf()
  vim.api.nvim_buf_set_lines(currentBuffer, 0, -1, false, lines)
  state.set_popup_keymaps(edit_popup, M.send_edits(tostring(root_node.id), note_node.root_note_id or note_node.id))
end

-- This function sends the edited comment to the Go server
M.send_edits       = function(discussion_id, note_id)
  return function(text)
    local json_table = {
      discussion_id = discussion_id,
      note_id = note_id,
      comment = text
    }
    local json = vim.json.encode(json_table)
    job.run_job("/comment", "PATCH", json, function(data)
      vim.notify(data.message, vim.log.levels.INFO)
      M.redraw_text(text)
    end)
  end
end

-- This comment (settings.discussion_tree.toggle_resolved) will toggle the resolved status of the current discussion and send the change to the Go server
M.toggle_resolved  = function()
  local note = M.tree:get_node()
  if not note or not note.resolvable then return end

  local json_table = {
    discussion_id = note.id,
    note_id = note.root_note_id,
    resolved = not note.resolved,
  }

  local json = vim.json.encode(json_table)
  job.run_job("/comment", "PATCH", json, function(data)
    vim.notify(data.message, vim.log.levels.INFO)
    M.redraw_resolved_status(note, not note.resolved)
  end)
end

-- This function (settings.discussion_tree.jump_to_reviewer) will jump the cursor to the reviewer's location associated with the note. The implementation depends on the reviewer
M.jump_to_reviewer = function()
  local file_name, new_line, old_line, error = M.get_note_location()
  if error ~= nil then
    vim.notify(error, vim.log.levels.ERROR)
    return
  end
  reviewer.jump(file_name, new_line, old_line)
end

-- This function (settings.discussion_tree.jump_to_file) will jump to the file changed in a new tab
M.jump_to_file     = function()
  local file_name, new_line, old_line, error = M.get_note_location()
  if error ~= nil then
    vim.notify(error, vim.log.levels.ERROR)
    return
  end
  vim.cmd.tabnew()
  u.jump_to_file(file_name, (new_line or old_line))
end

-- This function (settings.discussion_tree.toggle_node) expands/collapses the current node and its children
M.toggle_node      = function()
  local node = M.tree:get_node()
  if node == nil then return end
  local children = node:get_child_ids()
  if node == nil then return end
  if node:is_expanded() then
    node:collapse()
    for _, child in ipairs(children) do
      M.tree:get_node(child):collapse()
    end
  else
    for _, child in ipairs(children) do
      M.tree:get_node(child):expand()
    end
    node:expand()
  end

  M.tree:render()
end


--
-- 🌲 Helper Functions
--

M.redraw_resolved_status   = function(note, mark_resolved)
  local current_text = M.tree.nodes.by_id["-" .. note.id].text
  local target = mark_resolved and 'resolved' or 'unresolved'
  local current = mark_resolved and 'unresolved' or 'resolved'

  local function set_property(key, val)
    M.tree.nodes.by_id["-" .. note.id][key] = val
  end

  local has_symbol = function(s)
    return state.settings.discussion_tree[s] ~= nil and state.settings.discussion_tree[s] ~= ''
  end

  set_property('resolved', mark_resolved)

  if not has_symbol(current) and not has_symbol(target) then return end

  if not has_symbol(current) and has_symbol(target) then
    set_property('text', (current_text .. " " .. state.settings.discussion_tree[target]))
  elseif has_symbol(current) and not has_symbol(target) then
    set_property('text', u.remove_last_chunk(current_text))
  else
    set_property('text', (u.remove_last_chunk(current_text) .. " " .. state.settings.discussion_tree[target]))
  end

  M.tree:render()
end

M.redraw_text              = function(text)
  local current_node = M.tree:get_node()
  local note_node = M.get_note_node(current_node)

  local childrenIds = note_node:get_child_ids()
  for _, value in ipairs(childrenIds) do
    M.tree:remove_node(value)
  end

  local newNoteTextNodes = {}
  for bodyLine in text:gmatch("[^\n]+") do
    table.insert(newNoteTextNodes, NuiTree.Node({ text = bodyLine, is_body = true }, {}))
  end

  M.tree:set_nodes(newNoteTextNodes, "-" .. note_node.id)
  M.tree:render()
end

M.get_root_node            = function(node)
  if (not node.is_root) then
    local parent_id = node:get_parent_id()
    return M.get_root_node(M.tree:get_node(parent_id))
  else
    return node
  end
end

M.get_note_node            = function(node)
  if (not node.is_note) then
    local parent_id = node:get_parent_id()
    if parent_id == nil then return node end
    return M.get_note_node(M.tree:get_node(parent_id))
  else
    return node
  end
end

local attach_uuid          = function(str)
  return { text = str, id = u.uuid() }
end

M.build_note_body          = function(note, resolve_info)
  local text_nodes = {}
  for bodyLine in note.body:gmatch("[^\n]+") do
    local line = attach_uuid(bodyLine)
    table.insert(text_nodes, NuiTree.Node({
      new_line = note.position.new_line,
      old_line = note.position.old_line,
      text = line.text,
      id = line.id,
      is_body = true
    }, {}))
  end

  local resolve_symbol = ''
  if resolve_info ~= nil and resolve_info.resolvable then
    resolve_symbol = resolve_info.resolved and state.settings.discussion_tree.resolved or
        state.settings.discussion_tree.unresolved
  end

  local noteHeader = "@" .. note.author.username .. " " .. u.format_date(note.created_at) .. " " .. resolve_symbol

  return noteHeader, text_nodes
end

M.build_note               = function(note, resolve_info)
  local text, text_nodes = M.build_note_body(note, resolve_info)
  local note_node = NuiTree.Node({
    text = text,
    id = note.id,
    file_name = note.position.new_path,
    new_line = note.position.new_line,
    old_line = note.position.old_line,
    is_note = true,
  }, text_nodes)

  return note_node, text, text_nodes
end

M.add_note_to_tree         = function(note, discussion_id)
  local note_node = M.build_note(note)
  note_node:expand()
  M.tree:add_node(note_node, discussion_id and ("-" .. discussion_id) or nil)
  M.tree:render()
  vim.notify("Sent reply!", vim.log.levels.INFO)
end

M.refresh_tree             = function()
  job.run_job("/discussions", "GET", nil, function(data)
    if type(data.discussions) ~= "table" then
      vim.notify("No discussions for this MR")
      return
    end

    if not M.split_buf or (vim.fn.bufwinid(M.split_buf) == -1) then return end

    vim.api.nvim_buf_set_option(M.split_buf, 'modifiable', true)
    vim.api.nvim_buf_set_option(M.split_buf, 'readonly', false)
    vim.api.nvim_buf_set_lines(M.split_buf, 0, -1, false, {})
    vim.api.nvim_buf_set_option(M.split_buf, 'readonly', true)
    vim.api.nvim_buf_set_option(M.split_buf, 'modifiable', false)

    local tree_nodes = M.add_discussions_to_table(data.discussions)
    M.tree = NuiTree({ nodes = tree_nodes, bufnr = M.split_buf })
    M.set_tree_keymaps()
    M.tree:render()
    vim.api.nvim_buf_set_option(M.split_buf, 'filetype', 'markdown')
  end)
end

M.add_discussions_to_table = function(discussions)
  local t = {}
  for _, discussion in ipairs(discussions) do
    local discussion_children = {}

    -- These properties are filled in by the first note
    local root_text = ''
    local root_note_id = ''
    local root_file_name = ''
    local root_id = 0
    local root_text_nodes = {}
    local resolvable = false
    local resolved = false
    local root_new_line = nil
    local root_old_line = nil

    for j, note in ipairs(discussion.notes) do
      if j == 1 then
        __, root_text, root_text_nodes = M.build_note(note, { resolved = note.resolved, resolvable = note.resolvable })
        root_file_name = note.position.new_path
        root_new_line = note.position.new_line
        root_old_line = note.position.old_line
        root_id = discussion.id
        root_note_id = note.id
        resolvable = note.resolvable
        resolved = note.resolved
      else -- Otherwise insert it as a child node...
        local note_node = M.build_note(note)
        table.insert(discussion_children, note_node)
      end
    end

    -- Creates the first node in the discussion, and attaches children
    local body = u.join_tables(root_text_nodes, discussion_children)
    local root_node = NuiTree.Node({
      text = root_text,
      is_note = true,
      is_root = true,
      id = root_id,
      root_note_id = root_note_id,
      file_name = root_file_name,
      new_line = root_new_line,
      old_line = root_old_line,
      resolvable = resolvable,
      resolved = resolved
    }, body)

    table.insert(t, root_node)
  end

  return t
end

M.get_note_location        = function()
  local node = M.tree:get_node()
  if node == nil then return nil, nil, nil, "Could not get node" end
  local discussion_node = M.get_root_node(node)
  if discussion_node == nil then return nil, nil, nil, "Could not get discussion node" end
  return discussion_node.file_name, discussion_node.new_line, discussion_node.old_line
end

return M