package api

import (
	"errors"
	"net/http"
	"strconv"

	"github.com/gin-gonic/gin"

	"gitea.stevedudenhoeffer.com/steve/pansy/internal/domain"
	"gitea.stevedudenhoeffer.com/steve/pansy/internal/service"
)

// Grow journal (#52). Entries hang off a garden even when they're about one bed
// or one plop, which is what lets the permission check be the ordinary garden
// role check with nothing new invented.

// journalResponse is the body of GET /gardens/:id/journal.
type journalResponse struct {
	Entries []domain.JournalEntry `json:"entries"`
	HasMore bool                  `json:"hasMore"`
}

// journalCreateRequest is the body for POST /gardens/:id/journal. observedAt
// defaults to today when omitted — the common case is writing about now.
type journalCreateRequest struct {
	ObjectID   *int64  `json:"objectId"`
	PlantingID *int64  `json:"plantingId"`
	Body       string  `json:"body" binding:"required"`
	ObservedAt *string `json:"observedAt"`
}

// journalUpdateRequest is the body for PATCH /journal/:id. Only the text and the
// date it describes are editable; an entry's target and author are fixed.
type journalUpdateRequest struct {
	Body       *string `json:"body"`
	ObservedAt *string `json:"observedAt"`
	Version    int64   `json:"version" binding:"required"`
}

func (h *handlers) listJournal(c *gin.Context) {
	gardenID, ok := parseIDParam(c, "id")
	if !ok {
		return
	}
	q := service.JournalQuery{
		Limit:  intQuery(c, "limit", 0),
		Offset: intQuery(c, "offset", 0),
	}
	var err error
	if q.ObjectID, err = optionalIDQuery(c, "objectId"); err != nil {
		writeAPIError(c, http.StatusBadRequest, "INVALID_INPUT", "invalid objectId")
		return
	}
	if q.PlantingID, err = optionalIDQuery(c, "plantingId"); err != nil {
		writeAPIError(c, http.StatusBadRequest, "INVALID_INPUT", "invalid plantingId")
		return
	}
	if from := c.Query("from"); from != "" {
		q.From = &from
	}
	if to := c.Query("to"); to != "" {
		q.To = &to
	}

	entries, hasMore, err := h.svc.ListJournal(c.Request.Context(), mustActor(c).ID, gardenID, q)
	if err != nil {
		writeServiceError(c, err)
		return
	}
	c.JSON(http.StatusOK, journalResponse{Entries: entries, HasMore: hasMore})
}

func (h *handlers) createJournalEntry(c *gin.Context) {
	gardenID, ok := parseIDParam(c, "id")
	if !ok {
		return
	}
	var req journalCreateRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		writeAPIError(c, http.StatusBadRequest, "INVALID_INPUT", "invalid entry: a body is required")
		return
	}
	e, err := h.svc.CreateJournalEntry(c.Request.Context(), mustActor(c).ID, gardenID, service.JournalInput{
		ObjectID: req.ObjectID, PlantingID: req.PlantingID, Body: req.Body, ObservedAt: req.ObservedAt,
	})
	if err != nil {
		writeServiceError(c, err)
		return
	}
	c.JSON(http.StatusCreated, e)
}

func (h *handlers) updateJournalEntry(c *gin.Context) {
	id, ok := parseIDParam(c, "id")
	if !ok {
		return
	}
	var req journalUpdateRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		writeAPIError(c, http.StatusBadRequest, "INVALID_INPUT", "invalid update: a current version is required")
		return
	}
	e, err := h.svc.UpdateJournalEntry(c.Request.Context(), mustActor(c).ID, id,
		service.JournalPatch{Body: req.Body, ObservedAt: req.ObservedAt}, req.Version)
	if err != nil {
		if errors.Is(err, domain.ErrVersionConflict) {
			writeVersionConflict(c, e)
			return
		}
		writeServiceError(c, err)
		return
	}
	c.JSON(http.StatusOK, e)
}

func (h *handlers) deleteJournalEntry(c *gin.Context) {
	id, ok := parseIDParam(c, "id")
	if !ok {
		return
	}
	if err := h.svc.DeleteJournalEntry(c.Request.Context(), mustActor(c).ID, id); err != nil {
		writeServiceError(c, err)
		return
	}
	c.Status(http.StatusNoContent)
}

// optionalIDQuery reads a positive int64 query parameter, or nil when absent.
// A present-but-malformed value is an error rather than a silent nil, so a typo
// doesn't quietly widen a filter to the whole garden.
func optionalIDQuery(c *gin.Context, name string) (*int64, error) {
	raw := c.Query(name)
	if raw == "" {
		return nil, nil
	}
	id, err := strconv.ParseInt(raw, 10, 64)
	if err != nil || id < 1 {
		return nil, errors.New("invalid id")
	}
	return &id, nil
}