package docker

import (
	"log"

	"github.com/mitchellh/multistep"
	"github.com/mitchellh/packer/common"
	"github.com/mitchellh/packer/packer"
)

const BuilderId = "packer.docker"
const BuilderIdImport = "packer.post-processor.docker-import"

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{Ctx: &b.config.ctx, Ui: ui}
	if err := driver.Verify(); err != nil {
		return nil, err
	}

	version, err := driver.Version()
	if err != nil {
		return nil, err
	}
	log.Printf("[DEBUG] Docker version: %s", version.String())

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

	if b.config.Commit {
		steps = append(steps, new(StepCommit))
	} else {
		steps = append(steps, new(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)
	}

	var artifact packer.Artifact
	// No errors, must've worked
	if b.config.Commit {
		artifact = &ImportArtifact{
			IdValue:        state.Get("image_id").(string),
			BuilderIdValue: BuilderIdImport,
			Driver:         driver,
		}
	} else {
		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()
	}
}