package handlers

import (
	"context"
	"net/http"
	"time"

	"bookhoard/internal/database"
	wsync "bookhoard/internal/sync"

	"github.com/google/uuid"
	"github.com/jackc/pgx/v5/pgtype"
	"github.com/labstack/echo/v5"
)

// DeletedAnnotationResponse is one entry of the deleted-annotation history
// for a book (the book page's "recently deleted" list). Restoring returns the
// row to the active set; purging removes it permanently.
type DeletedAnnotationResponse struct {
	ID             string    `json:"id"`
	AnnotationType string    `json:"annotation_type"`
	DisplayText    string    `json:"display_text"`
	SecondaryText  string    `json:"secondary_text,omitempty"`
	Color          string    `json:"color,omitempty"`
	DeletedAt      time.Time `json:"deleted_at"`
	CreatedAt      time.Time `json:"created_at"`
}

// DeletedAnnotationsForBook builds the deleted-annotation history for a user
// and book. Shared by the JSON API and the book page's server-rendered modal.
func DeletedAnnotationsForBook(ctx context.Context, db *database.Queries, userID, mediaItemID pgtype.UUID) []DeletedAnnotationResponse {
	rows, err := db.ListDeletedAnnotationsForBook(ctx, database.ListDeletedAnnotationsForBookParams{
		MediaItemID: mediaItemID,
		UserID:      userID,
	})
	if err != nil {
		return []DeletedAnnotationResponse{}
	}

	response := make([]DeletedAnnotationResponse, 0, len(rows))
	for _, row := range rows {
		entry := DeletedAnnotationResponse{
			ID:             uuid.UUID(row.ID.Bytes).String(),
			AnnotationType: row.AnnotationType,
			DisplayText:    row.DisplayText,
			SecondaryText:  row.SecondaryText.String,
			Color:          row.Color.String,
		}
		if row.DeletedAt.Valid {
			entry.DeletedAt = row.DeletedAt.Time
		}
		if row.CreatedAt.Valid {
			entry.CreatedAt = row.CreatedAt.Time
		}
		response = append(response, entry)
	}
	return response
}

// GetDeletedAnnotations handles GET /api/media-items/:id/annotations/deleted
func (mh *MediaHandler) GetDeletedAnnotations(c *echo.Context) error {
	userUUID, mediaUUID, err := mh.parseUserAndMediaIDs(c)
	if err != nil {
		return err
	}

	response := DeletedAnnotationsForBook(c.Request().Context(), mh.db, userUUID, mediaUUID)

	return c.JSON(http.StatusOK, map[string]interface{}{
		"deleted_annotations": response,
		"total":               len(response),
	})
}

// RestoreDeletedAnnotation handles POST /api/media-items/:id/annotations/:annotationId/restore
// Body/query: annotation_type=highlight|note|bookmark
func (mh *MediaHandler) RestoreDeletedAnnotation(c *echo.Context) error {
	userUUID, mediaUUID, annotationUUID, kind, errResp := mh.parseAnnotationHistoryRequest(c, true)
	if errResp != nil {
		return errResp
	}

	if mh.annotationSvc == nil {
		return c.JSON(http.StatusServiceUnavailable, map[string]string{"error": "annotation service unavailable"})
	}

	restored, err := mh.annotationSvc.RestoreAnnotationByID(c.Request().Context(), kind, userUUID, mediaUUID, annotationUUID)
	if err != nil {
		return c.JSON(http.StatusInternalServerError, map[string]string{"error": "failed to restore annotation"})
	}
	if !restored {
		return c.JSON(http.StatusNotFound, map[string]string{"error": "deleted annotation not found"})
	}

	return c.JSON(http.StatusOK, map[string]interface{}{"restored": true})
}

// PurgeDeletedAnnotation handles DELETE /api/media-items/:id/annotations/:annotationId
// Query: annotation_type=highlight|note|bookmark. Permanent — removes the
// tombstoned row from the history.
func (mh *MediaHandler) PurgeDeletedAnnotation(c *echo.Context) error {
	userUUID, mediaUUID, annotationUUID, kind, errResp := mh.parseAnnotationHistoryRequest(c, false)
	if errResp != nil {
		return errResp
	}

	if mh.annotationSvc == nil {
		return c.JSON(http.StatusServiceUnavailable, map[string]string{"error": "annotation service unavailable"})
	}

	purged, err := mh.annotationSvc.PurgeAnnotationByID(c.Request().Context(), kind, userUUID, mediaUUID, annotationUUID)
	if err != nil {
		return c.JSON(http.StatusInternalServerError, map[string]string{"error": "failed to purge annotation"})
	}
	if !purged {
		return c.JSON(http.StatusNotFound, map[string]string{"error": "deleted annotation not found"})
	}

	return c.JSON(http.StatusOK, map[string]interface{}{"purged": true})
}

// parseUserAndMediaIDs extracts the authenticated user and the media item
// from the route. A non-nil error has already been written as the response.
func (mh *MediaHandler) parseUserAndMediaIDs(c *echo.Context) (pgtype.UUID, pgtype.UUID, error) {
	userID := c.Get("user_id").(string)
	userUUID, err := uuid.Parse(userID)
	if err != nil {
		return pgtype.UUID{}, pgtype.UUID{}, c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid user"})
	}
	mediaID := c.Param("id")
	mediaIDUUID, err := uuid.Parse(mediaID)
	if err != nil {
		return pgtype.UUID{}, pgtype.UUID{}, c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid media item id"})
	}
	return pgtype.UUID{Bytes: userUUID, Valid: true}, pgtype.UUID{Bytes: mediaIDUUID, Valid: true}, nil
}

// parseAnnotationHistoryRequest extracts user, media item, annotation ID, and
// the annotation_type (from query param or JSON body — restore posts a body,
// purge uses a query param). A non-nil error has already been written.
func (mh *MediaHandler) parseAnnotationHistoryRequest(c *echo.Context, allowBody bool) (pgtype.UUID, pgtype.UUID, pgtype.UUID, string, error) {
	userUUID, mediaUUID, err := mh.parseUserAndMediaIDs(c)
	if err != nil {
		return pgtype.UUID{}, pgtype.UUID{}, pgtype.UUID{}, "", err
	}

	annotationID := c.Param("annotationId")
	annotationUUID, err := uuid.Parse(annotationID)
	if err != nil {
		return pgtype.UUID{}, pgtype.UUID{}, pgtype.UUID{}, "", c.JSON(http.StatusBadRequest, map[string]string{"error": "invalid annotation id"})
	}

	kind := c.QueryParam("annotation_type")
	if kind == "" && allowBody {
		var body struct {
			AnnotationType string `json:"annotation_type"`
		}
		if c.Bind(&body) == nil {
			kind = body.AnnotationType
		}
	}
	if !wsync.ValidAnnotationKind(kind) {
		return pgtype.UUID{}, pgtype.UUID{}, pgtype.UUID{}, "", c.JSON(http.StatusBadRequest, map[string]string{"error": "annotation_type must be highlight, note, or bookmark"})
	}

	return userUUID, mediaUUID, pgtype.UUID{Bytes: annotationUUID, Valid: true}, kind, nil
}