local config = require("gitea.config")
local uv = vim.loop

local M = {}
local token_cached = nil

-- Attempt to read the token file from disk
local function read_token_file(path)
  local fd = uv.fs_open(path, "r", 438) -- 0666 in decimal
  if not fd then return nil end
  local stat = uv.fs_fstat(fd)
  local data = uv.fs_read(fd, stat.size, 0)
  uv.fs_close(fd)
  return data
end

-- Write token file
local function write_token_file(path, token)
  local fd = uv.fs_open(path, "w", 384) -- 0600 in decimal
  if not fd then
    error("[gitea.nvim] Failed to open token file for writing: " .. path)
  end
  uv.fs_write(fd, token, -1)
  uv.fs_close(fd)
end

-- Checks if the token file is in .gitignore, if not ask user
local function ensure_ignored(token_file, ignore_file)
  -- Read .gitignore lines if present
  local file = io.open(ignore_file, "r")
  local lines = {}
  if file then
    for line in file:lines() do
      table.insert(lines, line)
    end
    file:close()
  end
  -- Check if token_file is in .gitignore
  for _, l in ipairs(lines) do
    if l == token_file then
      return
    end
  end
  -- Not in ignore, ask user
  vim.schedule(function()
    vim.cmd([[echohl WarningMsg]])
    vim.cmd([[echo "gitea.nvim: We recommend adding ']]..token_file..[[' to ']]..ignore_file..[['. Add now? (y/N)"]])
    vim.cmd([[echohl None]])

    local ans = vim.fn.getchar()
    ans = vim.fn.nr2char(ans)

    if ans == "y" or ans == "Y" then
      local f = io.open(ignore_file, "a")
      if f then
        f:write("\n" .. token_file .. "\n")
        f:close()
        vim.notify("Added '"..token_file.."' to '"..ignore_file.."'", vim.log.levels.INFO)
      else
        vim.notify("Failed to open '"..ignore_file.."' for appending.", vim.log.levels.ERROR)
      end
    else
      vim.notify("Ok, not adding token file to '"..ignore_file.."'. Be mindful of security!", vim.log.levels.WARN)
    end
  end)
end

-- Parse .git/config or `git remote get-url origin` to guess the Gitea server
local function detect_gitea_server()
  -- Attempt: use `git config remote.origin.url`
  local cmd = "git config remote.origin.url"
  local url = vim.fn.systemlist(cmd)[1]
  if vim.v.shell_error ~= 0 or not url or url == "" then
    return nil
  end
  -- Example: https://gitea.myserver.com/owner/repo.git
  -- Strip `.git` suffix if present
  url = url:gsub("%.git$", "")
  -- Attempt to extract domain, e.g. "https://gitea.myserver.com"
  -- We'll do a naive pattern match
  local protocol, domain_and_path = url:match("^(https?://)(.*)$")
  if not protocol or not domain_and_path then
    -- Could be SSH or something else
    -- For instance: git@gitea.myserver.com:owner/repo.git
    -- Try a different parse
    local user_host, path = url:match("^(.-):(.*)$")
    if user_host and path and user_host:match(".*@") then
      -- user_host could be "git@gitea.myserver.com"
      local host = user_host:match("@(.*)")
      if host then
        return "https://"..host
      end
    end
    -- Fallback
    return nil
  end

  -- domain_and_path might be "gitea.myserver.com/owner/repo"
  -- just extract "gitea.myserver.com"
  local server = domain_and_path:match("^([^/]+)")
  if not server then
    return nil
  end
  return protocol .. server
end

-- Called during plugin setup or first command usage
function M.ensure_token()
  if token_cached then
    return token_cached
  end

  local cfg = config.values
  local token_file = cfg.config_file
  local ignore_file = cfg.ignore_file

  -- Attempt to detect the Gitea server if not provided
  if not cfg.server_url or cfg.server_url == "" then
    cfg.server_url = detect_gitea_server()
  end
  if not cfg.server_url then
    vim.notify("[gitea.nvim] Could not detect Gitea server from .git/config. Please configure manually.", vim.log.levels.WARN)
  end

  local token_data = read_token_file(token_file)
  if token_data and token_data ~= "" then
    token_cached = token_data
    return token_cached
  end

  -- If we reach here, no token was found
  vim.schedule(function()
    vim.cmd([[echohl WarningMsg]])
    vim.cmd([[echo "gitea.nvim: No Gitea token found. Please enter your Gitea Personal Access Token:"]])
    vim.cmd([[echohl None]])

    local user_token = vim.fn.input("Token: ")
    vim.cmd("redraw")

    if user_token == nil or user_token == "" then
      vim.notify("[gitea.nvim] No token provided, plugin may not work properly.", vim.log.levels.ERROR)
      return
    end

    write_token_file(token_file, user_token)
    token_cached = user_token
    vim.notify("Token saved to " .. token_file .. ".", vim.log.levels.INFO)

    -- Offer to add token_file to .gitignore
    ensure_ignored(token_file, ignore_file)
  end)

  return nil
end

function M.get_token()
  return token_cached
end

return M