---@return vim.api.keyset.win_config
local function get_winopts()
  local horiz = vim.opt.fillchars:get().horiz or "─"

  local height = math.ceil(vim.o.lines * 0.3)
  local offset = vim.o.cmdheight + 1

  return {
    relative = "editor",
    col = 0,
    row = vim.o.lines - height - offset - 1,
    height = height,
    width = vim.o.columns,
    style = "minimal",
    border = { horiz, horiz, horiz, "", "", "", "", "" },
  }
end

---@class jamjar.Terminal.proto
---@field cmd? string
---@field cwd? string
---@field winoptsfn? fun(): vim.api.keyset.win_config
---@field on_open? fun(self: jamjar.Terminal)

---@class jamjar.Terminal : jamjar.Terminal.proto
---@field cmd string
---@field buf integer
---@field win? integer
local Terminal = {}
Terminal.__index = Terminal

local function get_defaultopts()
  return {
    cmd = vim.o.shell,
    on_open = function(self)
      vim.api.nvim_set_option_value(
        "winhighlight",
        "Normal:Normal,NormalNC:NormalNC,FloatBorder:WinSeparator",
        { win = self.win }
      )
    end,
  }
end

---@param opts? jamjar.Terminal.proto
function Terminal:new(opts)
  return setmetatable(vim.tbl_extend("force", get_defaultopts(), opts or {}), self)
end

function Terminal:init()
  self.buf = vim.api.nvim_create_buf(true, true)
  vim.api.nvim_set_option_value("buftype", "nofile", { buf = self.buf })

  vim._with({ buf = self.buf }, function()
    vim.fn.jobstart(self.cmd, {
      term = true,
      cwd = self.cwd,
      on_exit = function()
        self:delete()
      end,
    })
  end)
end

function Terminal:toggle()
  if not self.win then
    self:open()
    return
  end

  local wcfg = vim.api.nvim_win_get_config(self.win)
  local hidden = wcfg.hide

  if hidden then
    self:open()
  else
    self:close()
  end
end

function Terminal:open()
  if not self.win then
    if not self.buf then
      self:init()
    end
    self.win = vim.api.nvim_open_win(self.buf, true, self.winoptsfn and self.winoptsfn() or get_winopts())
    vim.api.nvim_set_option_value("signcolumn", "no", { win = self.win })
    vim.api.nvim_set_option_value("foldcolumn", "0", { win = self.win })
    self.on_open(self)
  else
    vim.api.nvim_win_set_config(self.win, {
      hide = false,
    })
    vim.api.nvim_set_current_win(self.win)
  end
end

function Terminal:close()
  if self.win then
    vim.api.nvim_win_set_config(self.win, {
      hide = true,
    })
    if vim.api.nvim_get_current_win() == self.win then
      vim.cmd.wincmd("p")
    end
  end
end

function Terminal:quit()
  if self.win then
    vim.api.nvim_win_close(self.win, true)
    self.win = nil
  end
end

function Terminal:delete()
  self:quit()

  if self.buf and vim.api.nvim_buf_is_valid(self.buf) then
    vim.bo[self.buf].buflisted = false
    vim.api.nvim_buf_delete(self.buf, { unload = true })
    self.buf = nil
  end
end

return Terminal