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

local M = {}
local token_cached = nil

-- Read token file from disk (if present)
local function read_token_file(path)
  local fd = uv.fs_open(path, "r", 438)
  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 to disk with restricted permissions
local function write_token_file(path, token)
  local fd = uv.fs_open(path, "w", 384) -- 0600 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

----------------------------------------------------------------------------
--- Attempt to detect the Gitea server from remote.origin.url or fail
----------------------------------------------------------------------------
local function detect_gitea_server()
  -- 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, "No valid remote.origin.url found"
  end

  -- Remove trailing ".git" if present
  url = url:gsub("%.git$", "")

  -- Check for HTTPS style: https://my.gitea.com/owner/repo
  local protocol, domain_and_path = url:match("^(https?://)(.*)$")
  if protocol and domain_and_path then
    local server = domain_and_path:match("^([^/]+)")
    if server and server ~= "" then
      return protocol .. server
    end
  end

  -- Check for SSH style: git@my.gitea.com:owner/repo
  local user_host, path = url:match("^(.-):(.*)$")
  if user_host and user_host:match(".*@") then
    local host = user_host:match("@(.*)")
    if host and host ~= "" then
      -- We'll assume https for Gitea, if your instance is not https,
      -- you can adapt or forcibly use "http://" below
      return "https://" .. host
    end
  end

  return nil, "Unable to parse Gitea host from remote.origin.url: " .. url
end

----------------------------------------------------------------------------
--- DO NOT PROMPT for server_url, do not fallback to "gitea.example.com"
--- If we cannot auto-detect, we throw an error.
----------------------------------------------------------------------------
local function ensure_server_url()
  local server, err = detect_gitea_server()
  if not server then
    error(string.format("[gitea.nvim] Failed to auto-detect Gitea server: %s", err))
  end
  config.values.server_url = server
end

----------------------------------------------------------------------------
--- The user must have a Gitea token, we read from disk or error if missing
----------------------------------------------------------------------------
local function ensure_token_file()
  local token_file = config.values.config_file
  local token_data = read_token_file(token_file)
  if token_data and token_data ~= "" then
    -- Trim leading/trailing whitespace/newlines so we don't send a trailing "\n"
    token_data = token_data:gsub("^%s+", ""):gsub("%s+$", "")
    token_cached = token_data
    return
  end
  error(
    "[gitea.nvim] No token found in " .. token_file ..
    ". Please manually create and store your Gitea token there with mode 600."
  )
end

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

  ensure_server_url()
  ensure_token_file()
  return token_cached
end

function M.get_token()
  return token_cached
end

return M