package classes

import (
	"context"
	"errors"
	"regexp"
	"strings"
	"time"

	"git.golem15.com/golem15/sm-feedback-plugin/models"
	"git.golem15.com/golem15/summercms/modules/lagoon/attach"
	"gocloud.dev/blob"
	"gorm.io/gorm"
)

// The G15Office sync job's contract: SubmitFeedback queues one per stored
// submission, the worker files it (SyncFeedbackToG15Office).
const (
	// SyncG15OfficeKind is the River kind of the job.
	SyncG15OfficeKind = "golem15.feedback.sync_g15office"
	// SyncG15OfficeQueue is the job's queue.
	SyncG15OfficeQueue = "feedback"
	// SyncG15OfficeLabel is the summer_jobs label, the PHP job class.
	SyncG15OfficeLabel = `Golem15\Feedback\Jobs\SyncFeedbackToG15Office`
	// SyncG15OfficeAttempts is SyncFeedbackToG15Office::$tries.
	SyncG15OfficeAttempts = 3
)

// SyncG15OfficeArgs is the job's argument: the submission to file.
type SyncG15OfficeArgs struct {
	SubmissionID uint `json:"submission_id"`
}

// Kind is the River job kind.
func (SyncG15OfficeArgs) Kind() string { return SyncG15OfficeKind }

// SyncDeps are what one run of the job needs, resolved per run.
type SyncDeps struct {
	DB     *gorm.DB
	Bucket *blob.Bucket
	Client *G15OfficeClient
}

// SyncG15Office is SyncFeedbackToG15Office::handle: it files the submission
// as a G15Office task (title, Markdown description, type, the settings'
// task status and priority) and attaches its screenshot. Success stores
// status sent and the task id; any failure stores status failed and the
// error and returns the error, so the job is retried. A submission that is
// gone is skipped. An unconfigured client fails before any request, so
// nothing leaves the application.
//
// Unlike PHP, a retry never files a second task: a submission already sent
// with a task id is skipped, the task id is stored as soon as CreateTask
// returns it, and a retry of a submission that has one only re-attempts
// the screenshot attachment.
func SyncG15Office(ctx context.Context, deps SyncDeps, args SyncG15OfficeArgs) error {
	if deps.DB == nil {
		return errors.New("feedback: database is not configured")
	}
	db := deps.DB.WithContext(ctx)
	var rows []models.Submission
	if err := db.Where("id = ?", args.SubmissionID).Limit(1).Find(&rows).Error; err != nil {
		return err
	}
	if len(rows) == 0 {
		return nil
	}
	sub := rows[0]
	if sub.Status == models.StatusSent && hasTaskID(&sub) {
		return nil
	}
	id, err := fileTask(ctx, deps, &sub)
	if err != nil {
		msg := err.Error()
		if uerr := db.Model(&models.Submission{}).Where("id = ?", sub.ID).Updates(map[string]any{
			"status": models.StatusFailed, "g15office_error": msg, "updated_at": time.Now(),
		}).Error; uerr != nil {
			return errors.Join(err, uerr)
		}
		return err
	}
	return db.Model(&models.Submission{}).Where("id = ?", sub.ID).Updates(map[string]any{
		"status": models.StatusSent, "g15office_task_id": id, "g15office_error": nil, "updated_at": time.Now(),
	}).Error
}

// hasTaskID reports whether an earlier attempt already filed the task.
func hasTaskID(sub *models.Submission) bool {
	return sub.G15OfficeTaskID != nil && *sub.G15OfficeTaskID != ""
}

func fileTask(ctx context.Context, deps SyncDeps, sub *models.Submission) (string, error) {
	var id string
	if hasTaskID(sub) {
		id = *sub.G15OfficeTaskID
	} else {
		created, err := createTask(ctx, deps, sub)
		if err != nil {
			return "", err
		}
		id = created
	}
	if err := attachScreenshot(ctx, deps, sub, id); err != nil {
		return "", err
	}
	return id, nil
}

// createTask files the submission as a new G15Office task and stores the
// task id at once, so a later failure (the attachment) is retried against
// this task rather than filing another.
func createTask(ctx context.Context, deps SyncDeps, sub *models.Submission) (string, error) {
	settings, err := models.Instance(ctx, deps.DB)
	if err != nil {
		return "", err
	}
	fields := TaskFields{
		Title:       TaskTitle(sub.Message),
		Description: TaskDescription(sub),
		Type:        sub.G15OfficeTaskType(),
		Priority:    "normal",
	}
	if s := settings.G15OfficeTaskStatus; s != nil && phpTruthy(*s) {
		fields.Status = *s
	}
	if p := settings.G15OfficeTaskPriority; p != nil && phpTruthy(*p) {
		fields.Priority = *p
	}
	task, err := deps.Client.CreateTask(ctx, fields)
	if err != nil {
		return "", err
	}
	id := taskID(task)
	if id == "" {
		return "", errors.New("g15office did not return a task id.")
	}
	if err := deps.DB.WithContext(ctx).Model(&models.Submission{}).Where("id = ?", sub.ID).Updates(map[string]any{
		"g15office_task_id": id, "updated_at": time.Now(),
	}).Error; err != nil {
		return "", err
	}
	sub.G15OfficeTaskID = &id
	return id, nil
}

// attachScreenshot uploads the submission's screenshot, when it has one,
// to the task.
func attachScreenshot(ctx context.Context, deps SyncDeps, sub *models.Submission, id string) error {
	file, err := ScreenshotOf(ctx, deps.DB, sub.ID)
	if err != nil {
		return err
	}
	if file == nil {
		return nil
	}
	if deps.Bucket == nil {
		return errors.New("feedback: upload bucket is not configured")
	}
	r, err := deps.Bucket.NewReader(ctx, attach.BlobKey(file.DiskName), nil)
	if err != nil {
		return err
	}
	_, err = deps.Client.AttachFile(ctx, id, file.FileName, file.ContentType, r)
	_ = r.Close()
	return err
}

// whitespaceRun is PCRE's \s+ without the u flag: ASCII space, tab, LF, VT, FF
// and CR (Go's \s leaves out VT).
var whitespaceRun = regexp.MustCompile(`[\t\n\v\f\r ]+`)

// TaskTitle is SyncFeedbackToG15Office::buildTitle: "Feedback: " and the
// message with whitespace runs collapsed, trimmed and cut to 80 columns.
func TaskTitle(message string) string {
	collapsed := strings.Trim(whitespaceRun.ReplaceAllString(message, " "), " \t\n\r\x00\x0B")
	return "Feedback: " + StrLimit(collapsed, 80, "...")
}

// TaskDescription is SyncFeedbackToG15Office::buildDescription: the message,
// a rule, one bullet per metadata line (page, then the reporter email and
// the user agent when set) and the console log in a code fence, cut to
// 4000 columns, blocks separated by blank lines.
func TaskDescription(sub *models.Submission) string {
	blocks := []string{sub.Message, "---"}
	meta := []string{"- **Page:** " + sub.PageURL}
	if sub.Email != nil && phpTruthy(*sub.Email) {
		meta = append(meta, "- **Reporter email:** "+*sub.Email)
	}
	if sub.UserAgent != nil && phpTruthy(*sub.UserAgent) {
		meta = append(meta, "- **User agent:** "+*sub.UserAgent)
	}
	blocks = append(blocks, strings.Join(meta, "\n"))
	if sub.ConsoleLog != nil && phpTruthy(*sub.ConsoleLog) {
		blocks = append(blocks, "**Console log:**\n```\n"+StrLimit(*sub.ConsoleLog, 4000, "… (truncated)")+"\n```")
	}
	return strings.Join(blocks, "\n\n")
}