package helios

import (
	"io"
	"time"

	"git.bazzel.dev/bmallen/helios/pkg/state"
	"github.com/aws/smithy-go/ptr"
	"github.com/sirupsen/logrus"
)

type (
	Workflow struct {
		name  string
		jobs  jobs
		c     Context
		start *time.Time
		end   *time.Time
		log   *logrus.Logger
	}
	job struct {
		name     string
		steps    steps
		needs    []string
		workflow *Workflow
		start    *time.Time
		end      *time.Time
		err      error
	}
	jobs      []*job
	jobOption interface {
		Job(j *job)
	}
	step struct {
		name     string
		f        StepFunc
		start    *time.Time
		end      *time.Time
		workflow *Workflow
		job      *job
		err      error
	}
	steps []*step
	needs struct {
		name string
	}

	Context interface {
		Get(key string) any
		Set(key string, value any)
		Delete(key string)
		Keys() []string
		Range(f func(key string, value any) bool)
		ID() string
	}
	StepFunc func(ctx Context) error
)

func NewWorkflow(name string) *Workflow {
	w := &Workflow{
		name: name,
		jobs: jobs{},
		c:    state.New(),
		log:  logrus.New(),
	}

	return w
}

func (w *Workflow) Logger(writer io.Writer) *Workflow {
	w.log.SetOutput(writer)
	return w
}

func (w *Workflow) Run() (err error) {
	w.start = ptr.Time(time.Now())
	defer func() {
		w.end = ptr.Time(time.Now())
	}()

	for _, j := range w.jobs {
		w.log.Printf("# Job: %s\n", j.name)
		skip := false
		for _, n := range j.needs {
			for _, jj := range w.jobs {
				if jj.name == n {
					if jj.end == nil || jj.err != nil {
						skip = true
						break
					}
				}
			}
			if skip {
				break
			}
		}
		if skip {
			w.log.Printf("- skipping\n")
			continue
		}

		j.start = ptr.Time(time.Now())
		for _, step := range j.steps {
			w.log.Printf("- Step: %s / %s\n", j.name, step.name)
			j.err = step.Run()
			if j.err != nil {
				w.log.Printf("- Error: %s\n", j.err.Error())
				break

			}
			w.log.Printf("  Duration: %s\n", step.Duration())
		}
		j.end = ptr.Time(time.Now())
	}

	return err
}

func (w *Workflow) Job(name string, opts ...jobOption) *Workflow {
	job := &job{
		name:     name,
		steps:    steps{},
		needs:    []string{},
		workflow: w,
	}

	for _, opt := range opts {
		opt.Job(job)
	}

	w.jobs = append(w.jobs, job)
	return w
}

func Step(name string, f StepFunc) jobOption {
	return &step{
		name: name,
		f:    f,
	}
}

func (s *step) Job(j *job) {
	s.job = j
	s.workflow = j.workflow
	j.steps = append(j.steps, s)
}

func (s *step) Run() error {
	s.start = ptr.Time(time.Now())
	err := s.f(s.workflow.c)
	s.end = ptr.Time(time.Now())
	s.err = err
	return err
}

func (s *step) Duration() time.Duration {
	if s.end == nil || s.start == nil {
		return 0
	}
	return s.end.Sub(ptr.ToTime(s.start))
}

func Needs(name string) jobOption {
	return &needs{
		name: name,
	}
}

func (o *needs) Job(j *job) {
	j.needs = append(j.needs, o.name)
}