package main

import (
	"fmt"
	"sync"
	"time"

	"git.novox.be/novox/mesh-sdk/go/asks"
	sdk "git.novox.be/novox/mesh-sdk/go/delivery"
)

// fakeOperator is the gate's bucket asks and the teller behind it: it keeps the asks written, and answers as the test says
// (the teller's answer under the ask's key). In auto mode it approves every ask the moment it is read (the tests of other
// behaviour, which are not about the Approve). An ask is known here by its key (mesh-sdk go/delivery MergeAskKey), as the
// delivery keeps it.
type fakeOperator struct {
	mu        sync.Mutex
	now       func() time.Time
	auto      bool
	asked     []asks.Ask
	byKey     map[string]sdk.Ask
	order     []string
	seen      map[string]bool
	cancelled []string
	state     map[string]string
	answers   map[string]*sdk.Answer
	refuse    error
}

func newFakeOperator(now func() time.Time) *fakeOperator {
	return &fakeOperator{now: now, byKey: map[string]sdk.Ask{}, seen: map[string]bool{}, state: map[string]string{}, answers: map[string]*sdk.Answer{}}
}

func (o *fakeOperator) Ask(key string, a sdk.Ask) error {
	o.mu.Lock()
	defer o.mu.Unlock()
	if o.refuse != nil {
		return o.refuse
	}
	if err := a.Ask.Check(o.now()); err != nil {
		return err
	}
	if _, err := sdk.EncodeAsk(a); err != nil {
		return err
	}
	if o.state[key] == "open" && sdk.SameAsk(o.byKey[key], a) {
		return nil // the same ask is there, as kvOperator leaves it
	}
	o.asked = append(o.asked, a.Ask)
	o.byKey[key] = a
	if _, known := o.seen[key]; !known {
		o.order = append(o.order, key)
		o.seen[key] = true
	}
	o.state[key] = "open"
	delete(o.answers, key)
	return nil
}

func (o *fakeOperator) Cancel(key string) error {
	o.mu.Lock()
	defer o.mu.Unlock()
	o.cancelled = append(o.cancelled, key)
	o.state[key] = "cancelled"
	return nil
}

func (o *fakeOperator) Where(key string) (*sdk.Answer, error) {
	o.mu.Lock()
	defer o.mu.Unlock()
	if o.auto && o.state[key] == "open" {
		o.answerLocked(key, OptionApprove)
	}
	return o.answers[key], nil
}

// ask is the router's ask at a key, as the gate composed it.
func (o *fakeOperator) ask(key string) asks.Ask {
	if a, ok := o.byKey[key]; ok {
		return a.Ask
	}
	panic("no ask " + key)
}

func (o *fakeOperator) answerLocked(key, option string) {
	a := o.ask(key)
	opt, _ := a.Option(option)
	o.state[key] = "answered"
	o.answers[key] = &sdk.Answer{Option: option, Warrant: fmt.Sprintf("%s@%s", a.ID, o.now().UTC().Format(time.RFC3339)),
		Words: "the operator, via telegram, chose " + opt.Label}
}

// answer is the operator's choice, proven to the teller by the router and written by it.
func (o *fakeOperator) answer(key, option string) {
	o.mu.Lock()
	defer o.mu.Unlock()
	o.answerLocked(key, option)
}

// open is the keys of the asks waiting for an answer, in the order asked.
func (o *fakeOperator) open() []string {
	o.mu.Lock()
	defer o.mu.Unlock()
	var out []string
	for _, k := range o.order {
		if o.state[k] == "open" {
			out = append(out, k)
		}
	}
	return out
}

func (o *fakeOperator) count() int { o.mu.Lock(); defer o.mu.Unlock(); return len(o.asked) }