// Copyright 2012, 2013 Canonical Ltd.
// Licensed under the AGPLv3, see LICENCE file for details.

package client

import (
	"errors"
	"fmt"

	"github.com/juju/juju/apiserver/common"
	"github.com/juju/juju/apiserver/params"
	"github.com/juju/juju/cloudconfig/instancecfg"
	"github.com/juju/juju/controller/authentication"
	"github.com/juju/juju/environs"
	"github.com/juju/juju/state"
)

// InstanceConfig returns information from the environment config that
// is needed for machine cloud-init (for non-controllers only). It
// is exposed for testing purposes.
// TODO(rog) fix environs/manual tests so they do not need to call this, or move this elsewhere.
func InstanceConfig(st *state.State, machineId, nonce, dataDir string) (*instancecfg.InstanceConfig, error) {
	environConfig, err := st.ModelConfig()
	if err != nil {
		return nil, err
	}

	// Get the machine so we can get its series and arch.
	// If the Arch is not set in hardware-characteristics,
	// an error is returned.
	machine, err := st.Machine(machineId)
	if err != nil {
		return nil, err
	}
	hc, err := machine.HardwareCharacteristics()
	if err != nil {
		return nil, err
	}
	if hc.Arch == nil {
		return nil, fmt.Errorf("arch is not set for %q", machine.Tag())
	}

	// Find the appropriate tools information.
	agentVersion, ok := environConfig.AgentVersion()
	if !ok {
		return nil, errors.New("no agent version set in model configuration")
	}
	environment, err := st.Model()
	if err != nil {
		return nil, err
	}
	urlGetter := common.NewToolsURLGetter(environment.UUID(), st)
	toolsFinder := common.NewToolsFinder(st, st, urlGetter)
	findToolsResult, err := toolsFinder.FindTools(params.FindToolsParams{
		Number:       agentVersion,
		MajorVersion: -1,
		MinorVersion: -1,
		Series:       machine.Series(),
		Arch:         *hc.Arch,
	})
	if err != nil {
		return nil, err
	}
	if findToolsResult.Error != nil {
		return nil, findToolsResult.Error
	}
	tools := findToolsResult.List[0]

	// Find the API endpoints.
	env, err := environs.New(environConfig)
	if err != nil {
		return nil, err
	}
	apiInfo, err := environs.APIInfo(env)
	if err != nil {
		return nil, err
	}

	auth := authentication.NewAuthenticator(st.MongoConnectionInfo(), apiInfo)
	mongoInfo, apiInfo, err := auth.SetupAuthentication(machine)
	if err != nil {
		return nil, err
	}

	// Find requested networks.
	networks, err := machine.RequestedNetworks()
	if err != nil {
		return nil, err
	}

	// Figure out if secure connections are supported.
	info, err := st.StateServingInfo()
	if err != nil {
		return nil, err
	}
	secureServerConnection := info.CAPrivateKey != ""
	icfg, err := instancecfg.NewInstanceConfig(machineId, nonce, env.Config().ImageStream(), machine.Series(), "",
		secureServerConnection, networks, mongoInfo, apiInfo,
	)
	if err != nil {
		return nil, err
	}
	if dataDir != "" {
		icfg.DataDir = dataDir
	}
	icfg.Tools = tools
	err = instancecfg.FinishInstanceConfig(icfg, environConfig)
	if err != nil {
		return nil, err
	}
	return icfg, nil
}
