--- ### AstroNvim Updater
--
-- AstroNvim Updater utilities to use within AstroNvim and user configurations.
--
-- This module can also loaded with `local updater = require("astronvim.utils.updater")`
--
-- @module astronvim.utils.updater
-- @see astronvim.utils
-- @copyright 2022
-- @license GNU General Public License v3.0

local git = require "astronvim.utils.git"

local M = {}

local utils = require "astronvim.utils"
local notify = utils.notify

local function echo(messages)
  -- if no parameter provided, echo a new line
  messages = messages or { { "\n" } }
  if type(messages) == "table" then vim.api.nvim_echo(messages, false, {}) end
end

local function confirm_prompt(messages, type)
  return vim.fn.confirm(messages, "&Yes\n&No", (type == "Error" or type == "Warning") and 2 or 1, type or "Question")
    == 1
end

--- Helper function to generate AstroNvim snapshots (For internal use only)
---@param write? boolean Whether or not to write to the snapshot file (default: false)
---@return table # The plugin specification table of the snapshot
function M.generate_snapshot(write)
  local file
  local prev_snapshot = require(astronvim.updater.snapshot.module)
  for _, plugin in ipairs(prev_snapshot) do
    prev_snapshot[plugin[1]] = plugin
  end
  local plugins = assert(require("lazy").plugins())
  table.sort(plugins, function(l, r) return l[1] < r[1] end)
  local function git_commit(dir)
    local commit = assert(utils.cmd({ "git", "-C", dir, "rev-parse", "HEAD" }, false))
    if commit then return vim.trim(commit) end
  end
  if write == true then
    file = assert(io.open(astronvim.updater.snapshot.path, "w"))
    file:write "return {\n"
  end
  local snapshot = vim.tbl_map(function(plugin)
    plugin = { plugin[1], commit = git_commit(plugin.dir), version = plugin.version }
    if prev_snapshot[plugin[1]] and prev_snapshot[plugin[1]].version then
      plugin.version = prev_snapshot[plugin[1]].version
    end
    if file then
      file:write(("  { %q, "):format(plugin[1]))
      if plugin.version then
        file:write(("version = %q"):format(plugin.version))
      else
        file:write(("commit = %q"):format(plugin.commit))
      end
      file:write ", optional = true },\n"
    end
    return plugin
  end, plugins)
  if file then
    file:write "}\n"
    file:close()
  end
  return snapshot
end

--- Get the current AstroNvim version
---@param quiet? boolean Whether to quietly execute or send a notification
---@return string # The current AstroNvim version string
function M.version(quiet)
  local version = astronvim.install.version or git.current_version(false) or "unknown"
  if astronvim.updater.options.channel ~= "stable" then version = ("nightly (%s)"):format(version) end
  if version and not quiet then notify(("Version: *%s*"):format(version)) end
  return version
end

--- Get the full AstroNvim changelog
---@param quiet? boolean Whether to quietly execute or display the changelog
---@return table # The current AstroNvim changelog table of commit messages
function M.changelog(quiet)
  local summary = {}
  vim.list_extend(summary, git.pretty_changelog(git.get_commit_range()))
  if not quiet then echo(summary) end
  return summary
end

--- Attempt an update of AstroNvim
---@param target string The target if checking out a specific tag or commit or nil if just pulling
local function attempt_update(target, opts)
  -- if updating to a new stable version or a specific commit checkout the provided target
  if opts.channel == "stable" or opts.commit then
    return git.checkout(target, false)
  -- if no target, pull the latest
  else
    return git.pull(false)
  end
end

--- Cancelled update message
local cancelled_message = { { "Update cancelled", "WarningMsg" } }

--- Sync Packer and then update Mason
function M.update_packages()
  require("lazy").sync { wait = true }
  require("astronvim.utils.mason").update_all()
end

--- Create a table of options for the currently installed AstroNvim version
---@param write? boolean Whether or not to write to the rollback file (default: false)
---@return table # The table of updater options
function M.create_rollback(write)
  local snapshot = { branch = git.current_branch(), commit = git.local_head() }
  if snapshot.branch == "HEAD" then snapshot.branch = "main" end
  snapshot.remote = git.branch_remote(snapshot.branch, false) or "origin"
  snapshot.remotes = { [snapshot.remote] = git.remote_url(snapshot.remote) }

  if write == true then
    local file = assert(io.open(astronvim.updater.rollback_file, "w"))
    file:write("return " .. vim.inspect(snapshot, { newline = " ", indent = "" }))
    file:close()
  end

  return snapshot
end

--- AstroNvim's rollback to saved previous version function
function M.rollback()
  local rollback_avail, rollback_opts = pcall(dofile, astronvim.updater.rollback_file)
  if not rollback_avail then
    notify("No rollback file available", vim.log.levels.ERROR)
    return
  end
  M.update(rollback_opts)
end

--- Check if an update is available
---@param opts? table the settings to use for checking for an update
---@return table|boolean? # The information of an available update (`{ source = string, target = string }`), false if no update is available, or nil if there is an error
function M.update_available(opts)
  if not opts then opts = astronvim.updater.options end
  opts = require("astronvim.utils").extend_tbl({ remote = "origin" }, opts)
  -- if the git command is not available, then throw an error
  if not git.available() then
    notify(
      "`git` command is not available, please verify it is accessible in a command line. This may be an issue with your `PATH`",
      vim.log.levels.ERROR
    )
    return
  end

  -- if installed with an external package manager, disable the internal updater
  if not git.is_repo() then
    notify("Updater not available for non-git installations", vim.log.levels.ERROR)
    return
  end
  -- set up any remotes defined by the user if they do not exist
  for remote, entry in pairs(opts.remotes and opts.remotes or {}) do
    local url = git.parse_remote_url(entry)
    local current_url = git.remote_url(remote, false)
    local check_needed = false
    if not current_url then
      git.remote_add(remote, url)
      check_needed = true
    elseif
      current_url ~= url
      and confirm_prompt(
        ("Remote %s is currently: %s\n" .. "Would you like us to set it to %s ?"):format(remote, current_url, url)
      )
    then
      git.remote_update(remote, url)
      check_needed = true
    end
    if check_needed and git.remote_url(remote, false) ~= url then
      vim.api.nvim_err_writeln("Error setting up remote " .. remote .. " to " .. url)
      return
    end
  end
  local is_stable = opts.channel == "stable"
  if is_stable then
    opts.branch = "main"
  elseif not opts.branch then
    opts.branch = "nightly"
  end
  -- setup branch if missing
  if not git.ref_verify(opts.remote .. "/" .. opts.branch, false) then
    git.remote_set_branches(opts.remote, opts.branch, false)
  end
  -- fetch the latest remote
  if not git.fetch(opts.remote) then
    vim.api.nvim_err_writeln("Error fetching remote: " .. opts.remote)
    return
  end
  -- switch to the necessary branch only if not on the stable channel
  if not is_stable then
    local local_branch = (opts.remote == "origin" and "" or (opts.remote .. "_")) .. opts.branch
    if git.current_branch() ~= local_branch then
      echo {
        { "Switching to branch: " },
        { opts.remote .. "/" .. opts.branch .. "\n\n", "String" },
      }
      if not git.checkout(local_branch, false) then
        git.checkout("-b " .. local_branch .. " " .. opts.remote .. "/" .. opts.branch, false)
      end
    end
    -- check if the branch was switched to successfully
    if git.current_branch() ~= local_branch then
      vim.api.nvim_err_writeln("Error checking out branch: " .. opts.remote .. "/" .. opts.branch)
      return
    end
  end
  local update = { source = git.local_head() }
  if is_stable then -- if stable get tag commit
    local version_search = opts.version or "latest"
    update.version = git.latest_version(git.get_versions(version_search))
    if not update.version then -- continue only if stable version is found
      vim.api.nvim_err_writeln("Error finding version: " .. version_search)
      return
    end
    update.target = git.tag_commit(update.version)
  elseif opts.commit then -- if commit specified use it
    update.target = git.branch_contains(opts.remote, opts.branch, opts.commit) and opts.commit or nil
  else -- get most recent commit
    update.target = git.remote_head(opts.remote, opts.branch)
  end

  if not update.source or not update.target then -- continue if current and target commits were found
    vim.api.nvim_err_writeln "Error checking for updates"
    return
  elseif update.source ~= update.target then
    -- update available
    return update
  else
    return false
  end
end

--- AstroNvim's updater function
---@param opts? table the settings to use for the update
function M.update(opts)
  if not opts then opts = astronvim.updater.options end
  opts = require("astronvim.utils").extend_tbl(
    { remote = "origin", show_changelog = true, sync_plugins = true, auto_quit = false },
    opts
  )
  local available_update = M.update_available(opts)
  if available_update == nil then
    return
  elseif not available_update then -- continue if current and target commits were found
    notify "No updates available"
  elseif -- prompt user if they want to accept update
    not opts.skip_prompts
    and not confirm_prompt(
      ("Update available to %s\nUpdating requires a restart, continue?"):format(
        available_update.version or available_update.target
      )
    )
  then
    echo(cancelled_message)
    return
  else -- perform update
    local source, target = available_update.source, available_update.target
    M.create_rollback(true) -- create rollback file before updating
    -- calculate and print the changelog
    local changelog = git.get_commit_range(source, target)
    local breaking = git.breaking_changes(changelog)
    if
      #breaking > 0
      and not opts.skip_prompts
      and not confirm_prompt(
        ("Update contains the following breaking changes:\n%s\nWould you like to continue?"):format(
          table.concat(breaking, "\n")
        ),
        "Warning"
      )
    then
      echo(cancelled_message)
      return
    end
    -- attempt an update
    local updated = attempt_update(target, opts)
    -- check for local file conflicts and prompt user to continue or abort
    if
      not updated
      and not opts.skip_prompts
      and not confirm_prompt(
        "Unable to pull due to local modifications to base files.\nReset local files and continue?",
        "Error"
      )
    then
      echo(cancelled_message)
      return
    -- if continued and there were errors reset the base config and attempt another update
    elseif not updated then
      git.hard_reset(source)
      updated = attempt_update(target, opts)
    end
    -- if update was unsuccessful throw an error
    if not updated then
      vim.api.nvim_err_writeln "Error occurred performing update"
      return
    end
    -- print a summary of the update with the changelog
    local summary = {
      { "AstroNvim updated successfully to ", "Title" },
      { git.current_version(), "String" },
      { "!\n", "Title" },
      {
        opts.auto_quit and "AstroNvim will now update plugins and quit.\n\n"
          or "After plugins update, please restart.\n\n",
        "WarningMsg",
      },
    }
    if opts.show_changelog and #changelog > 0 then
      vim.list_extend(summary, { { "Changelog:\n", "Title" } })
      vim.list_extend(summary, git.pretty_changelog(changelog))
    end
    echo(summary)

    -- if the user wants to auto quit, create an autocommand to quit AstroNvim on the update completing
    if opts.auto_quit then
      vim.api.nvim_create_autocmd("User", {
        desc = "Auto quit AstroNvim after update completes",
        pattern = "AstroUpdateComplete",
        command = "quitall",
      })
    end

    require("lazy.core.plugin").load() -- force immediate reload of lazy
    if opts.sync_plugins then require("lazy").sync { wait = true } end
    utils.event "UpdateComplete"
  end
end

return M