package task

import (
	"bytes"
	"context"
	"fmt"
	"text/template"
	"time"

	"forge.cadoles.com/Cadoles/daddy/internal/mail"
	"forge.cadoles.com/Cadoles/daddy/internal/model"
	"github.com/pkg/errors"

	"forge.cadoles.com/Cadoles/daddy/internal/orm"

	"gitlab.com/wpetit/goweb/middleware/container"

	"gitlab.com/wpetit/goweb/logger"
)

type Newsletter struct {
	ctx             context.Context
	timeRange       time.Duration
	baseURL         string
	contentTemplate string
	subjectTemplate string
	from            string
}

func (t *Newsletter) Name() string {
	return "newsletter"
}

func (t *Newsletter) Run() {
	ctx := t.ctx

	logger.Info(ctx, "preparing newsletter", logger.F("timeRange", t.timeRange))

	contentTmpl, err := template.New("").Parse(t.contentTemplate)
	if err != nil {
		logger.Error(ctx, "could not parse newsletter content template", logger.E(errors.WithStack(err)))

		return
	}

	subjectTmpl, err := template.New("").Parse(t.subjectTemplate)
	if err != nil {
		logger.Error(ctx, "could not parse newsletter subject template", logger.E(errors.WithStack(err)))

		return
	}

	ctn := container.Must(ctx)
	orm := orm.Must(ctn)
	db := orm.DB()
	mailSrv := mail.Must(ctn)

	eventRepo := model.NewEventRepository(db)

	to := time.Now()
	from := to.Add(-t.timeRange)

	events, err := eventRepo.Search(ctx, &model.EventFilter{
		From: &from,
		To:   &to,
	})
	if err != nil {
		logger.Error(ctx, "could not search events", logger.E(errors.WithStack(err)))

		return
	}

	newWorkgroups := make([]*model.Workgroup, 0)
	newDecisionSupportFiles := make([]*model.DecisionSupportFile, 0)
	readyToVote := make([]*model.DecisionSupportFile, 0)

	workgroupRepo := model.NewWorkgroupRepository(db)
	dsfRepo := model.NewDSFRepository(db)

	for _, evt := range events {
		switch {
		case evt.Type == model.EventTypeCreated && evt.ObjectType == model.ObjectTypeWorkgroup:
			workgroup, err := workgroupRepo.Find(ctx, fmt.Sprintf("%d", evt.ObjectID))
			if err != nil {
				logger.Error(
					ctx, "could not find workgroup",
					logger.E(errors.WithStack(err)),
					logger.F("id", evt.ObjectID),
				)

				return
			}

			newWorkgroups = append(newWorkgroups, workgroup)

		case evt.Type == model.EventTypeCreated && evt.ObjectType == model.ObjectTypeDecisionSupportFile:
			dsf, err := dsfRepo.Find(ctx, fmt.Sprintf("%d", evt.ObjectID))
			if err != nil {
				logger.Error(
					ctx, "could not find decision support file",
					logger.E(errors.WithStack(err)),
					logger.F("id", evt.ObjectID),
				)

				return
			}

			newDecisionSupportFiles = append(newDecisionSupportFiles, dsf)

		case evt.Type == model.EventTypeStatusChanged && evt.ObjectType == model.ObjectTypeDecisionSupportFile:
			dsf, err := dsfRepo.Find(ctx, fmt.Sprintf("%d", evt.ObjectID))
			if err != nil {
				logger.Error(
					ctx, "could not find decision support file",
					logger.E(errors.WithStack(err)),
					logger.F("id", evt.ObjectID),
				)

				return
			}

			if dsf.Status == model.StatusReady {
				readyToVote = append(readyToVote, dsf)
			}
		}
	}

	hasEvents := len(newDecisionSupportFiles) > 0 || len(newWorkgroups) > 0

	userRepo := model.NewUserRepository(db)

	users, err := userRepo.All(ctx)
	if err != nil {
		logger.Error(ctx, "could not find users", logger.E(errors.WithStack(err)))

		return
	}

	var (
		contentBuff bytes.Buffer
		subjectBuff bytes.Buffer
	)

	for _, u := range users {
		tmplData := struct {
			User                    *model.User
			NewWorkgroups           []*model.Workgroup
			NewDecisionSupportFiles []*model.DecisionSupportFile
			ReadyToVote             []*model.DecisionSupportFile
			BaseURL                 string
			From                    time.Time
			To                      time.Time
			HasEvents               bool
		}{
			User:                    u,
			BaseURL:                 t.baseURL,
			NewWorkgroups:           newWorkgroups,
			NewDecisionSupportFiles: newDecisionSupportFiles,
			ReadyToVote:             readyToVote,
			From:                    from.Local(),
			To:                      to.Local(),
			HasEvents:               hasEvents,
		}

		err = contentTmpl.Execute(&contentBuff, tmplData)
		if err != nil {
			logger.Error(ctx, "could not execute newsletter content template", logger.E(errors.WithStack(err)))

			return
		}

		err = subjectTmpl.Execute(&subjectBuff, tmplData)
		if err != nil {
			logger.Error(ctx, "could not execute newsletter subject template", logger.E(errors.WithStack(err)))

			return
		}

		newsletterContent := contentBuff.String()
		newsletterSubject := subjectBuff.String()

		err := mailSrv.Send(
			mail.WithRecipients(u.Email),
			mail.WithSubject(newsletterSubject),
			mail.WithSender(t.from, ""),
			mail.WithBody(mail.ContentTypeText, newsletterContent, nil),
		)
		if err != nil {
			logger.Error(
				ctx, "could not send newsletter",
				logger.E(errors.WithStack(err)),
				logger.F("email", u.Email),
			)

			return
		}

		contentBuff.Reset()
		subjectBuff.Reset()
	}
}

func NewNewsletter(ctx context.Context, timeRange time.Duration, baseURL, contentTemplate, subjectTemplate, from string) *Newsletter {
	return &Newsletter{
		ctx:             ctx,
		timeRange:       timeRange,
		baseURL:         baseURL,
		contentTemplate: contentTemplate,
		subjectTemplate: subjectTemplate,
		from:            from,
	}
}