// CouchDB module for Duso
// Simple CRUD operations with Mango queries (no auth)

var DEFAULT_URL = "http://localhost:5984"
var DEFAULT_TIMEOUT = 30

// Helper: Make HTTP API calls
function api_call(method, url, body, timeout)
  if not timeout then
    timeout = DEFAULT_TIMEOUT
  end

  var opts = {method = method}

  if body then
    opts.headers = {"Content-Type" = "application/json"}
    opts.body = format_json(body)
  end

  var response = fetch(url, opts)

  // Parse response body if present
  var data = nil
  if response.body and len(response.body) > 0 then
    try
      data = parse_json(response.body)
    catch (e)
      data = nil
    end
  end

  // Check for HTTP errors
  if response.status >= 400 then
    var error_msg = response.status + " "
    if data and data.reason then
      error_msg = error_msg + data.reason
    else
      error_msg = error_msg + response.body
    end
    throw(error_msg)
  end

  return data
end

// Connection object: represents a single database
function connect(url, db_name)
  if not url then
    url = DEFAULT_URL
  end

  if not db_name then
    throw("db_name is required")
  end

  var db_url = url + "/" + db_name

  return {
    url = url,
    db_name = db_name,
    db_url = db_url,

    // Get a single document by ID
    get = function(doc_id)
      return api_call("GET", db_url + "/" + doc_id, nil)
    end,

    // Create or update a document
    // Document must have _id field
    put = function(doc)
      if not doc._id then
        throw("Document must have _id field")
      end
      return api_call("PUT", db_url + "/" + doc._id, doc)
    end,

    // Delete a document (requires _rev for optimistic locking)
    delete = function(doc_id, rev)
      if not doc_id or not rev then
        throw("doc_id and rev are required for delete")
      end
      var del_url = db_url + "/" + doc_id + "?rev=" + rev
      return api_call("DELETE", del_url, nil)
    end,

    // Query documents using Mango selector language
    // selector: {field = value, field2 = {$gt = 5}, ...}
    // options: {sort = [{field = "asc"}], limit = 10, skip = 0, fields = ["field1", "field2"]}
    query = function(selector, options)
      var body = {selector = selector}

      if options then
        if options.sort then
          body.sort = options.sort
        end
        if options.limit then
          body.limit = options.limit
        end
        if options.skip then
          body.skip = options.skip
        end
        if options.fields then
          body.fields = options.fields
        end
      end

      var result = api_call("POST", db_url + "/_find", body)
      return result.docs or []
    end,

    // Get database info
    info = function()
      return api_call("GET", db_url, nil)
    end,

    // Delete the entire database
    delete_db = function()
      return api_call("DELETE", db_url, nil)
    end,

    // Bulk insert/update documents
    // Pass array of documents (each must have _id)
    bulk = function(docs)
      var body = {docs = docs}
      return api_call("POST", db_url + "/_bulk_docs", body)
    end,

    // Create an index for faster queries
    // fields: array of field objects. Example: [{field1 = "asc"}, {field2 = "asc"}]
    create_index = function(fields, index_name)
      if not index_name then
        index_name = "auto"
      end

      var body = {
        index = {fields = fields},
        name = index_name
      }
      return api_call("POST", db_url + "/_index", body)
    end
  }
end

// Top-level: Create a new database
function create_database(url, db_name)
  if not url then
    url = DEFAULT_URL
  end

  if not db_name then
    throw("db_name is required")
  end

  var create_url = url + "/" + db_name
  var result = api_call("PUT", create_url, nil)

  // Return connection to the new database
  return connect(url, db_name)
end

// Top-level: List all databases
function list_databases(url)
  if not url then
    url = DEFAULT_URL
  end

  return api_call("GET", url + "/_all_dbs", nil)
end

// Top-level: Get server info
function server_info(url)
  if not url then
    url = DEFAULT_URL
  end

  return api_call("GET", url, nil)
end

// Export public API
return {
  connect = connect,
  create_database = create_database,
  list_databases = list_databases,
  server_info = server_info
}