package models

import (
	"context"
	"regexp"
	"strconv"
	"strings"
)

type EventHandler struct {
	ID          int                       `json:"id"`
	EventName   string                    `json:"eventName"`
	Conditions  map[string]EventCondition `json:"conditions"`
	OneShot     bool                      `json:"oneShot"`
	Priority    int                       `json:"priority"`
	TargetKind  ReferenceKind             `json:"targetKind"`
	TargetValue string                    `json:"targetValue"`
	Actions     EventAction               `json:"actions"`
}

type EventHandlerRepository interface {
	FindByID(ctx context.Context, id int) (*EventHandler, error)
	FetchAll(ctx context.Context) ([]EventHandler, error)
	Save(ctx context.Context, handler *EventHandler) error
	Delete(ctx context.Context, handler *EventHandler) error
}

type EventCondition struct {
	EQ  string `json:"eq,omitempty"`
	GT  string `json:"gt,omitempty"`
	GTE string `json:"gte,omitempty"`
	LT  string `json:"lt,omitempty"`
	LTE string `json:"lte,omitempty"`
}

type EventHandlerUpdate struct {
	SetEventName    *string                    `json:"setEventName"`
	SetPriority     *int                       `json:"setPriority"`
	SetTargetKind   *ReferenceKind             `json:"setTargetKind"`
	SetTargetValue  *string                    `json:"setTargetValue"`
	SetConditions   map[string]EventCondition  `json:"setConditions"`
	PatchConditions map[string]*EventCondition `json:"patchConditions"`
	SetActions      *EventAction               `json:"setActions"`
}

func (h *EventHandler) ApplyUpdate(update EventHandlerUpdate) {
	if update.SetEventName != nil {
		h.EventName = *update.SetEventName
	}
	if update.SetPriority != nil {
		h.Priority = *update.SetPriority
	}
	if update.SetTargetKind != nil {
		h.TargetKind = *update.SetTargetKind
	}
	if update.SetTargetValue != nil {
		h.TargetValue = *update.SetTargetValue
	}
	if update.SetActions != nil {
		h.Actions = *update.SetActions
	}

	if update.SetConditions != nil {
		h.Conditions = update.SetConditions
	}
	if update.PatchConditions != nil {
		if h.Conditions == nil {
			h.Conditions = make(map[string]EventCondition)
		}

		for key, value := range update.PatchConditions {
			if value == nil {
				delete(h.Conditions, key)
			} else {
				h.Conditions[key] = *value
			}
		}
	}
}

func (h *EventHandler) MatchesEvent(event Event, targets []Device) bool {
	if event.Name != h.EventName {
		return false
	}

	for key, condition := range h.Conditions {
		if !strings.ContainsRune(key, '.') && !event.HasPayload(key) {
			return false
		}

		if !condition.check(key, event.Payload[key], targets) {
			return false
		}
	}

	return true
}

func (c *EventCondition) check(key, value string, targets []Device) bool {
	any := strings.HasPrefix(key, "any.")
	all := strings.HasPrefix(key, "all.")
	if any || all {
		count := 0
		for _, target := range targets {
			if c.checkDevice(key[4:], target) {
				count++
			}
		}

		return (any && count > 0) || (all && count == len(targets))
	}

	return c.matches(value)
}

func (c *EventCondition) checkDevice(key string, device Device) bool {
	switch key {
	case "power":
		return c.matches(strconv.FormatBool(device.State.Power))
	case "color":
		return c.matches(device.State.Color.String())
	case "intensity":
		return c.matches(strconv.FormatFloat(device.State.Intensity, 'f', -1, 64))
	case "temperature":
		return c.matches(strconv.FormatFloat(device.State.Temperature, 'f', -1, 64))
	}

	return false
}

var numRegex = regexp.MustCompile("^{-[0-9].}+$")

func (c *EventCondition) matches(value string) bool {
	if numRegex.MatchString(value) {
		numValue, _ := strconv.ParseFloat(c.LT, 64)
		stillAlive := true

		if c.LT != "" {
			lt, _ := strconv.ParseFloat(c.LT, 64)
			stillAlive = numValue < lt
		}

		if stillAlive && c.LTE != "" {
			lte, _ := strconv.ParseFloat(c.LTE, 64)
			stillAlive = numValue <= lte
		}

		if stillAlive && c.EQ != "" {
			eq, _ := strconv.ParseFloat(c.EQ, 64)
			stillAlive = numValue == eq
		}

		if stillAlive && c.GTE != "" {
			gte, _ := strconv.ParseFloat(c.GTE, 64)
			stillAlive = numValue == gte
		}

		if stillAlive && c.GT != "" {
			gt, _ := strconv.ParseFloat(c.GT, 64)
			stillAlive = numValue > gt
		}

		return stillAlive
	} else if c.EQ != "" {
		return strings.ToLower(c.EQ) == strings.ToLower(value)
	} else {
		return false
	}
}

type EventAction struct {
	SetPower     *bool    `json:"setPower"`
	SetColor     *string  `json:"setColor"`
	SetIntensity *float64 `json:"setIntensity"`
	AddIntensity *float64 `json:"addIntensity"`
	FireEvent    *Event   `json:"fireEvent"`
}

func (action *EventAction) Apply(other EventAction) {
	if action.SetPower == nil {
		action.SetPower = other.SetPower
	}
	if action.SetColor == nil {
		action.SetColor = other.SetColor
	}
	if action.SetIntensity == nil && other.SetIntensity != nil {
		action.SetIntensity = other.SetIntensity
	}
	if action.AddIntensity == nil && action.SetIntensity == nil {
		action.AddIntensity = other.AddIntensity
	}
	if action.FireEvent == nil {
		action.FireEvent = other.FireEvent
	}
}