package main

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"regexp"
	"strconv"
	"strings"
	"time"

	"github.com/breel-render/spoc-bot-vr/model"
)

var (
	ErrIrrelevantMessage = errors.New("message isnt relevant to spoc bot vr")
)

type SlackToModel struct {
	pipeline Pipeline
}

type Models struct {
	Event   model.Event
	Message model.Message
	Thread  model.Thread
}

func NewSlackToModelPipeline(ctx context.Context, cfg Config) (Pipeline, error) {
	reader, err := NewQueue(ctx, "slack_event", cfg.driver)
	if err != nil {
		return Pipeline{}, err
	}
	writer, err := NewQueue(ctx, "new_message", cfg.driver)
	if err != nil {
		return Pipeline{}, err
	}
	return Pipeline{
		writer:  writer,
		reader:  reader,
		process: newSlackToModelProcess(cfg),
	}, nil
}

func newSlackToModelProcess(cfg Config) processFunc {
	return func(ctx context.Context, slack []byte) ([]byte, error) {
		s, err := parseSlack(slack)
		if err != nil {
			return nil, fmt.Errorf("failed to deserialize slack %w: %s", err, slack)
		}

		for pattern, ptr := range map[string]*string{
			cfg.AssetPattern:      &s.Asset,
			cfg.DatacenterPattern: &s.Datacenter,
			cfg.EventNamePattern:  &s.EventName,
		} {
			r := regexp.MustCompile(pattern)
			parsed := r.FindString(*ptr)
			for i, name := range r.SubexpNames() {
				if i > 0 && name != "" {
					parsed = r.FindStringSubmatch(*ptr)[i]
				}
			}
			*ptr = parsed
		}

		event := model.Event{}
		if s.Event != "" && s.Source != "" && s.TS > 0 && s.EventName != "" {
			event = model.NewEvent(s.Event, s.Source, s.TS, s.EventName, s.Asset, s.Datacenter, "TODO", s.Resolved)
		}
		message := model.Message{}
		if s.ID != "" && s.Source != "" && s.TS > 0 && s.Thread != "" {
			message = model.NewMessage(s.ID, s.Source, s.TS, "TODO", s.Plaintext, s.Thread)
		}
		thread := model.Thread{}
		if s.Thread != "" && s.Source != "" && s.TS > 0 && s.Event != "" {
			thread = model.NewThread(s.Thread, s.Source, s.TS, s.Channel, s.Event)
		}
		return json.Marshal(Models{
			Event:   event,
			Message: message,
			Thread:  thread,
		})
	}
}

type (
	parsedSlackMessage struct {
		ID         string
		TS         uint64
		Source     string
		Channel    string
		Thread     string
		EventName  string
		Event      string
		Plaintext  string
		Asset      string
		Resolved   bool
		Datacenter string
	}

	slackMessage struct {
		slackEvent
		Type      string
		TS        uint64 `json:"event_time"`
		Event     slackEvent
		MessageTS string `json:"ts"`
	}

	slackEvent struct {
		ID      string `json:"event_ts"`
		Channel string
		// rewrites
		Nested          *slackEvent `json:"message"`
		PreviousMessage *slackEvent `json:"previous_message"`
		// human
		ParentID string `json:"thread_ts"`
		Text     string
		Blocks   []slackBlock
		// bot
		Bot         slackBot `json:"bot_profile"`
		Attachments []slackAttachment
	}

	slackBlock struct {
		Elements []slackElement
	}

	slackElement struct {
		Elements []slackElement
		RichText string `json:"text"`
	}

	slackBot struct {
		Name string
	}

	slackAttachment struct {
		Color   string
		Title   string
		Text    string
		Fields  []slackField
		Actions []slackAction
	}

	slackField struct {
		Value string
		Title string
	}

	slackAction struct{}
)

func parseSlack(b []byte) (parsedSlackMessage, error) {
	s, err := _parseSlack(b)
	if err != nil {
		return parsedSlackMessage{}, err
	}

	/*
		if ch != "" {
			s.Event.Channel = ch
		}
	*/

	if s.Event.Bot.Name != "" {
		if len(s.Event.Attachments) == 0 {
			return parsedSlackMessage{}, ErrIrrelevantMessage
		} else if !strings.Contains(s.Event.Attachments[0].Title, ": Firing: ") {
			return parsedSlackMessage{}, ErrIrrelevantMessage
		}
		var tagsField string
		for _, field := range s.Event.Attachments[0].Fields {
			if field.Title == "Tags" {
				tagsField = field.Value
			}
		}
		return parsedSlackMessage{
			ID:         fmt.Sprintf("%s/%v", s.Event.ID, s.TS),
			TS:         s.TS,
			Source:     fmt.Sprintf(`https://renderinc.slack.com/archives/%s/p%s`, s.Event.Channel, strings.ReplaceAll(s.Event.ID, ".", "")),
			Channel:    s.Event.Channel,
			Thread:     s.Event.ID,
			EventName:  strings.Split(s.Event.Attachments[0].Title, ": Firing: ")[1],
			Event:      strings.TrimPrefix(strings.Split(s.Event.Attachments[0].Title, ":")[0], "#"),
			Plaintext:  s.Event.Attachments[0].Text,
			Asset:      s.Event.Attachments[0].Text,
			Resolved:   !strings.HasPrefix(s.Event.Attachments[0].Color, "F"),
			Datacenter: tagsField,
		}, nil
	}

	if s.Event.ParentID == "" {
		return parsedSlackMessage{}, ErrIrrelevantMessage
	}
	return parsedSlackMessage{
		ID:         fmt.Sprintf("%s/%v", s.Event.ParentID, s.TS),
		TS:         s.TS,
		Source:     fmt.Sprintf(`https://renderinc.slack.com/archives/%s/p%s`, s.Event.Channel, strings.ReplaceAll(s.Event.ParentID, ".", "")),
		Channel:    s.Event.Channel,
		Thread:     s.Event.ParentID,
		EventName:  "",
		Event:      "",
		Plaintext:  s.Event.Text,
		Asset:      "",
		Datacenter: "",
	}, nil
}

func _parseSlack(b []byte) (slackMessage, error) {
	var result slackMessage
	err := json.Unmarshal(b, &result)
	switch result.Type {
	case "message":
		result.Event = result.slackEvent
		result.TS, _ = strconv.ParseUint(strings.Split(result.MessageTS, ".")[0], 10, 64)
		result.Event.ID = result.MessageTS
	}
	if result.Event.Nested != nil && !result.Event.Nested.Empty() {
		result.Event.Blocks = result.Event.Nested.Blocks
		result.Event.Bot = result.Event.Nested.Bot
		result.Event.Attachments = result.Event.Nested.Attachments
		result.Event.Nested = nil
	}
	if result.Event.PreviousMessage != nil {
		if result.Event.PreviousMessage.ID != "" {
			result.Event.ID = result.Event.PreviousMessage.ID
		}
		result.Event.PreviousMessage = nil
	}
	return result, err
}

func (this slackEvent) Empty() bool {
	return fmt.Sprintf("%+v", this) == fmt.Sprintf("%+v", slackEvent{})
}

func (this parsedSlackMessage) Time() time.Time {
	return time.Unix(int64(this.TS), 0)
}