package docker

import (
	"github.com/mitchellh/multistep"
	"github.com/mitchellh/packer/common"
	"github.com/mitchellh/packer/packer"
	"log"
)

const BuilderId = "packer.docker"

type Builder struct {
	config *Config
	runner multistep.Runner
}

func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
	c, warnings, errs := NewConfig(raws...)
	if errs != nil {
		return warnings, errs
	}
	b.config = c

	return warnings, nil
}

func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packer.Artifact, error) {
	driver := &DockerDriver{Tpl: b.config.tpl, Ui: ui}
	if err := driver.Verify(); err != nil {
		return nil, err
	}

	steps := []multistep.Step{
		&StepTempDir{},
		&StepPull{},
		&StepRun{},
		&StepProvision{},
		&StepExport{},
	}

	// Setup the state bag and initial state for the steps
	state := new(multistep.BasicStateBag)
	state.Put("config", b.config)
	state.Put("hook", hook)
	state.Put("ui", ui)

	// Setup the driver that will talk to Docker
	state.Put("driver", driver)

	// Run!
	if b.config.PackerDebug {
		b.runner = &multistep.DebugRunner{
			Steps:   steps,
			PauseFn: common.MultistepDebugFn(ui),
		}
	} else {
		b.runner = &multistep.BasicRunner{Steps: steps}
	}

	b.runner.Run(state)

	// If there was an error, return that
	if rawErr, ok := state.GetOk("error"); ok {
		return nil, rawErr.(error)
	}

	// No errors, must've worked
	artifact := &ExportArtifact{path: b.config.ExportPath}
	return artifact, nil
}

func (b *Builder) Cancel() {
	if b.runner != nil {
		log.Println("Cancelling the step runner...")
		b.runner.Cancel()
	}
}