package webhook

import (
	"context"
	"fmt"
	"strings"
	"time"

	"gitea.oblak.solutions/dimitar/gitFlow/internal/httpclient"
)

// SlackSender posts to a Slack incoming webhook using Block Kit (mrkdwn).
type SlackSender struct {
	cfg  Config
	http *httpclient.Client
}

func newSlack(cfg Config) *SlackSender {
	return &SlackSender{cfg: cfg, http: httpclient.New(httpclient.WithTimeout(cfg.TimeoutOrDefault()))}
}

func (s *SlackSender) Name() string { return s.cfg.Name }

type slackMessage struct {
	Blocks []slackBlock `json:"blocks"`
}

type slackBlock struct {
	Type string     `json:"type"`
	Text *slackText `json:"text,omitempty"`
}

type slackText struct {
	Type string `json:"type"` // "mrkdwn" or "plain_text"
	Text string `json:"text"`
}

func (s *SlackSender) Send(ctx context.Context, payload Payload) error {
	msg := slackMessage{
		Blocks: []slackBlock{
			{Type: "header", Text: &slackText{Type: "plain_text", Text: "gitflow: scan results"}},
			{Type: "section", Text: &slackText{Type: "mrkdwn", Text: slackSummary(payload)}},
		},
	}
	if len(payload.Changed) > 0 {
		msg.Blocks = append(msg.Blocks,
			slackBlock{Type: "divider"},
			slackBlock{Type: "section", Text: &slackText{Type: "mrkdwn", Text: slackChanges(payload)}},
		)
	}
	msg.Blocks = append(msg.Blocks,
		slackBlock{Type: "context", Text: &slackText{Type: "mrkdwn", Text: slackFooter(payload)}},
	)

	return s.http.PostJSON(ctx, s.cfg.URL, nil, msg, nil)
}

func slackSummary(p Payload) string {
	s := p.Summary
	return fmt.Sprintf("Scanned *%s* — %d repos: %d clean, %d need attention, %d errors",
		p.ParentDir, s.Total, s.Clean, s.Attention, s.Errored)
}

func slackChanges(p Payload) string {
	var b strings.Builder
	b.WriteString("*Changed repositories:*\n")
	for _, r := range p.Changed {
		sym := statusSymbol(r.Status)
		line := fmt.Sprintf("• %s `%s` — %s _(%s)_",
			sym, r.Name, r.Status, r.Branch)
		if r.AheadBy > 0 || r.BehindBy > 0 {
			line += fmt.Sprintf(" +%d/-%d", r.AheadBy, r.BehindBy)
		}
		if n := r.FileCount(); n > 0 {
			line += fmt.Sprintf(" %d change(s)", n)
		}
		b.WriteString(line + "\n")
	}
	return b.String()
}

func slackFooter(p Payload) string {
	return fmt.Sprintf("_%s | gitflow_", p.Timestamp.Format(time.RFC3339))
}