package model

// SelectionTrace is populated by the selector while its candidate snapshot is
// still locked. It never retains Channel objects, keys or provider settings.
type SelectionTrace struct {
	Candidates []SelectionCandidate `json:"candidates"`
	Total      int                  `json:"candidate_total"`
	SelectedID int                  `json:"-"`
}

type SelectionCandidate struct {
	ChannelID int    `json:"channel_id"`
	Name      string `json:"name"`
	Group     string `json:"group"`
	Model     string `json:"model"`
	Priority  int64  `json:"priority"`
	Weight    int    `json:"weight"`
	Reason    string `json:"reason"`
}

func (t *SelectionTrace) Add(ch *Channel, id int, group, model, reason string) {
	if t == nil {
		return
	}
	t.Total++
	if len(t.Candidates) >= 100 {
		return
	}
	c := SelectionCandidate{ChannelID: id, Group: group, Model: model, Reason: reason}
	if ch != nil {
		c.Name = ch.Name
		c.Priority = ch.GetPriority()
		c.Weight = ch.GetWeight()
	}
	t.Candidates = append(t.Candidates, c)
}

func (t *SelectionTrace) Finish(ch *Channel) {
	if t == nil || ch == nil {
		return
	}
	t.SelectedID = ch.Id
	for i := range t.Candidates {
		c := &t.Candidates[i]
		if c.ChannelID == ch.Id && c.Reason == "eligible" {
			c.Reason = "selected"
		}
		if c.Reason == "eligible" && c.Priority != ch.GetPriority() {
			c.Reason = "different_priority"
		}
	}
}