package asanarules

import "fmt"
import "time"

import "cloud.google.com/go/civil"
import "github.com/firestuff/asana-rules/asanaclient"

type queryMutator func(*asanaclient.WorkspaceClient, *asanaclient.SearchQuery) error
type taskActor func(*asanaclient.WorkspaceClient, *asanaclient.Task) error
type workspaceClientGetter func(*asanaclient.Client) (*asanaclient.WorkspaceClient, error)

type periodic struct {
	duration time.Duration
	done     chan bool

  workspaceClientGetter workspaceClientGetter
  queryMutators []queryMutator
  taskActors []taskActor
}

var periodics = []*periodic{}

func Every(d time.Duration) *periodic {
	ret := &periodic{
		duration: d,
		done:     make(chan bool),
	}

	periodics = append(periodics, ret)

	return ret
}

func Loop() {
	client := asanaclient.NewClientFromEnv()

	for _, periodic := range periodics {
		periodic.start(client)
	}

	for _, periodic := range periodics {
		periodic.wait()
	}
}

func (p *periodic) InMyTasksSections(names ...string) *periodic {
  p.queryMutators = append(p.queryMutators, func(wc *asanaclient.WorkspaceClient, q *asanaclient.SearchQuery) error {
		me, err := wc.GetMe()
		if err != nil {
      return err
		}

		utl, err := wc.GetUserTaskList(me)
		if err != nil {
      return err
		}

		secs, err := wc.GetSections(utl)
		if err != nil {
      return err
		}

    secsByName := map[string]*asanaclient.Section{}
    for _, sec := range secs {
      secsByName[sec.Name] = sec
    }

    for _, name := range names {
      sec, found := secsByName[name]
      if !found {
        return fmt.Errorf("Section '%s' not found", name)
      }

      q.SectionsAny = append(q.SectionsAny, sec)
    }

    return nil
  })

  return p
}

func (p *periodic) DueInDays(days int) *periodic {
  p.queryMutators = append(p.queryMutators, func(wc *asanaclient.WorkspaceClient, q *asanaclient.SearchQuery) error {
    d := civil.DateOf(time.Now())
    d = d.AddDays(days)
    dueOn := d.String()
    q.DueOn = &dueOn
    return nil
  })

  return p
}

func (p *periodic) InWorkspace(name string) *periodic {
  p.workspaceClientGetter = func(c *asanaclient.Client) (*asanaclient.WorkspaceClient, error) {
    return c.InWorkspace(name)
  }

  return p
}

func (p *periodic) OnlyIncomplete() *periodic {
  p.queryMutators = append(p.queryMutators, func(wc *asanaclient.WorkspaceClient, q *asanaclient.SearchQuery) error {
    q.Completed = asanaclient.FALSE
    return nil
  })

  return p
}

func (p *periodic) OnlyComplete() *periodic {
  p.queryMutators = append(p.queryMutators, func(wc *asanaclient.WorkspaceClient, q *asanaclient.SearchQuery) error {
    q.Completed = asanaclient.TRUE
    return nil
  })

  return p
}

func (p *periodic) PrintTasks() *periodic {
  p.taskActors = append(p.taskActors, func(wc *asanaclient.WorkspaceClient, t *asanaclient.Task) error {
    fmt.Printf("%s\n", t)
    return nil
  })

  return p
}

func (p *periodic) start(client *asanaclient.Client) {
  err := p.validate()
  if err != nil {
    panic(err)
  }

	go p.loop(client)
}

func (p *periodic) validate() error {
  return nil
}

func (p *periodic) wait() {
	<-p.done
}

func (p *periodic) loop(client *asanaclient.Client) {
	ticker := time.NewTicker(p.duration)

	for {
		<-ticker.C
    err := p.exec(client)
    if err != nil {
      fmt.Printf("%s\n", err)
      // continue
    }
	}

	close(p.done)
}

func (p *periodic) exec(c *asanaclient.Client) error {
  wc, err := p.workspaceClientGetter(c)
  if err != nil {
    return err
  }

  q := &asanaclient.SearchQuery{}

  for _, mut := range p.queryMutators {
    err = mut(wc, q)
    if err != nil {
      return err
    }
  }

  tasks, err := wc.Search(q)
  if err != nil {
    return err
  }

  for _, task := range tasks {
    for _, act := range p.taskActors {
      err = act(wc, task)
      if err != nil {
        return err
      }
    }
  }

  return nil
}