package api

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

	"github.com/gin-gonic/gin"

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

// Seed lots (#50): what you actually bought, and what's left of it. Private to
// the buyer — a lot is never shared along with a garden — so every handler here
// scopes to the session actor with no garden in the picture.

// seedLotCreateRequest is the body for POST /seed-lots.
type seedLotCreateRequest struct {
	PlantID        int64    `json:"plantId" binding:"required"`
	Vendor         string   `json:"vendor"`
	SourceURL      string   `json:"sourceUrl"`
	SKU            string   `json:"sku"`
	LotCode        string   `json:"lotCode"`
	PurchasedAt    *string  `json:"purchasedAt"`
	PackedForYear  *int     `json:"packedForYear"`
	Quantity       float64  `json:"quantity"`
	Unit           string   `json:"unit" binding:"required"`
	CostCents      *int     `json:"costCents"`
	GerminationPct *float64 `json:"germinationPct"`
	Notes          string   `json:"notes"`
}

func (r seedLotCreateRequest) toInput() service.SeedLotInput {
	return service.SeedLotInput{
		PlantID: r.PlantID, Vendor: r.Vendor, SourceURL: r.SourceURL, SKU: r.SKU,
		LotCode: r.LotCode, PurchasedAt: r.PurchasedAt, PackedForYear: r.PackedForYear,
		Quantity: r.Quantity, Unit: r.Unit, CostCents: r.CostCents,
		GerminationPct: r.GerminationPct, Notes: r.Notes,
	}
}

// seedLotUpdateRequest is the body for PATCH /seed-lots/:id: every field
// optional, plus the required current version. The nullable columns are
// json.RawMessage so an explicit null (clear it) is distinguishable from an
// absent field (leave it alone). plantId is not accepted — see SeedLotPatch.
type seedLotUpdateRequest struct {
	Vendor         *string         `json:"vendor"`
	SourceURL      *string         `json:"sourceUrl"`
	SKU            *string         `json:"sku"`
	LotCode        *string         `json:"lotCode"`
	PurchasedAt    json.RawMessage `json:"purchasedAt"`
	PackedForYear  json.RawMessage `json:"packedForYear"`
	Quantity       *float64        `json:"quantity"`
	Unit           *string         `json:"unit"`
	CostCents      json.RawMessage `json:"costCents"`
	GerminationPct json.RawMessage `json:"germinationPct"`
	Notes          *string         `json:"notes"`
	Version        int64           `json:"version" binding:"required"`
}

func (r seedLotUpdateRequest) toPatch() (service.SeedLotPatch, error) {
	p := service.SeedLotPatch{
		Vendor: r.Vendor, SourceURL: r.SourceURL, SKU: r.SKU, LotCode: r.LotCode,
		Quantity: r.Quantity, Unit: r.Unit, Notes: r.Notes,
	}
	var err error
	if p.PurchasedAt, p.SetPurchasedAt, err = parseNullable[string](r.PurchasedAt); err != nil {
		return p, err
	}
	if p.PackedForYear, p.SetPackedForYear, err = parseNullable[int](r.PackedForYear); err != nil {
		return p, err
	}
	if p.CostCents, p.SetCostCents, err = parseNullable[int](r.CostCents); err != nil {
		return p, err
	}
	if p.GerminationPct, p.SetGerminationPct, err = parseNullable[float64](r.GerminationPct); err != nil {
		return p, err
	}
	return p, nil
}

func (h *handlers) listSeedLots(c *gin.Context) {
	var plantID *int64
	if raw := c.Query("plantId"); raw != "" {
		id, err := strconv.ParseInt(raw, 10, 64)
		if err != nil || id < 1 {
			writeAPIError(c, http.StatusBadRequest, "INVALID_INPUT", "invalid plantId")
			return
		}
		plantID = &id
	}
	lots, err := h.svc.ListSeedLots(c.Request.Context(), mustActor(c).ID, plantID)
	if err != nil {
		writeServiceError(c, err)
		return
	}
	c.JSON(http.StatusOK, lots)
}

func (h *handlers) createSeedLot(c *gin.Context) {
	var req seedLotCreateRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		writeAPIError(c, http.StatusBadRequest, "INVALID_INPUT", "invalid seed lot: plantId and unit are required")
		return
	}
	lot, err := h.svc.CreateSeedLot(c.Request.Context(), mustActor(c).ID, req.toInput())
	if err != nil {
		writeServiceError(c, err)
		return
	}
	c.JSON(http.StatusCreated, lot)
}

func (h *handlers) getSeedLot(c *gin.Context) {
	id, ok := parseIDParam(c, "id")
	if !ok {
		return
	}
	lot, err := h.svc.GetSeedLot(c.Request.Context(), mustActor(c).ID, id)
	if err != nil {
		writeServiceError(c, err)
		return
	}
	c.JSON(http.StatusOK, lot)
}

func (h *handlers) updateSeedLot(c *gin.Context) {
	id, ok := parseIDParam(c, "id")
	if !ok {
		return
	}
	var req seedLotUpdateRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		writeAPIError(c, http.StatusBadRequest, "INVALID_INPUT", "invalid update: a current version is required")
		return
	}
	patch, err := req.toPatch()
	if err != nil {
		writeAPIError(c, http.StatusBadRequest, "INVALID_INPUT", "invalid update payload")
		return
	}
	lot, err := h.svc.UpdateSeedLot(c.Request.Context(), mustActor(c).ID, id, patch, req.Version)
	if err != nil {
		if errors.Is(err, domain.ErrVersionConflict) {
			writeVersionConflict(c, lot)
			return
		}
		writeServiceError(c, err)
		return
	}
	c.JSON(http.StatusOK, lot)
}

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