local ok, Job = pcall(require, 'plenary.job')
if not ok then
  return
end

local source = {}

source.new = function()
  local self = setmetatable({ cache = {} }, { __index = source })

  return self
end

source.complete = function(self, _, callback)
  local bufnr = vim.api.nvim_get_current_buf()

  -- This just makes sure that we only hit the GH API once per session.
  --
  -- You could remove this if you wanted, but this just makes it so we're
  -- good programming citizens.
  if not self.cache[bufnr] then
    Job:new({
      -- Uses `gh` executable to request the issues from the remote repository.
      'gh',
      'issue',
      'list',
      '--limit',
      '1000',
      '--json',
      'title,number,body',

      on_exit = function(job)
        local result = job:result()
        local ok, parsed = pcall(vim.json.decode, table.concat(result, ''))
        if not ok then
          vim.notify('Failed to parse gh result')
          return
        end

        local items = {}
        for _, gh_item in ipairs(parsed) do
          gh_item.body = string.gsub(gh_item.body or '', '\r', '')

          table.insert(items, {
            label = string.format('#%s', gh_item.number),
            documentation = {
              kind = 'markdown',
              value = string.format('# %s\n\n%s', gh_item.title, gh_item.body),
            },
          })
        end

        callback({ items = items, isIncomplete = false })
        self.cache[bufnr] = items
      end,
    }):start()
  else
    callback({ items = self.cache[bufnr], isIncomplete = false })
  end
end

source.get_trigger_characters = function()
  return { '#' }
end

source.is_available = function()
  return vim.bo.filetype == 'gitcommit'
end

require('cmp').register_source('gh_issues', source.new())