package handlers

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

	"git.mchus.pro/mchus/priceforge/internal/models"
	"git.mchus.pro/mchus/priceforge/internal/services/pricelist"
	"github.com/gin-gonic/gin"
)

type PricelistHandler struct {
	service *pricelist.Service
	dbUser  string
}

func NewPricelistHandler(service *pricelist.Service, dbUser string) *PricelistHandler {
	return &PricelistHandler{service: service, dbUser: dbUser}
}

func (h *PricelistHandler) List(c *gin.Context) {
	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
	perPage, _ := strconv.Atoi(c.DefaultQuery("per_page", "20"))
	source := c.Query("source")
	activeOnly := c.DefaultQuery("active_only", "false") == "true"

	var (
		list  []models.PricelistSummary
		total int64
		err   error
	)
	if activeOnly {
		list, total, err = h.service.ListActiveBySource(page, perPage, source)
	} else {
		list, total, err = h.service.ListBySource(page, perPage, source)
	}
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"pricelists": list, "total": total, "page": page, "per_page": perPage})
}

func (h *PricelistHandler) Get(c *gin.Context) {
	id, err := strconv.ParseUint(c.Param("id"), 10, 32)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid pricelist ID"})
		return
	}
	pl, err := h.service.GetByID(uint(id))
	if err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "pricelist not found"})
		return
	}
	c.JSON(http.StatusOK, pl)
}

func (h *PricelistHandler) Create(c *gin.Context) {
	canWrite, debugInfo := h.service.CanWriteDebug()
	if !canWrite {
		c.JSON(http.StatusForbidden, gin.H{"error": "pricelist write is not allowed", "debug": debugInfo})
		return
	}

	var req struct {
		Source string `json:"source"`
		Items  []struct {
			LotName string  `json:"lot_name"`
			Price   float64 `json:"price"`
		} `json:"items"`
	}
	if err := c.ShouldBindJSON(&req); err != nil && !errors.Is(err, io.EOF) {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	source := string(models.NormalizePricelistSource(req.Source))
	createdBy := h.dbUser
	if strings.TrimSpace(createdBy) == "" {
		createdBy = "unknown"
	}
	items := make([]pricelist.CreateItemInput, 0, len(req.Items))
	for _, item := range req.Items {
		items = append(items, pricelist.CreateItemInput{LotName: item.LotName, Price: item.Price})
	}

	pl, err := h.service.CreateForSourceWithProgress(createdBy, source, items, nil)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusCreated, pl)
}

func (h *PricelistHandler) CreateWithProgress(c *gin.Context) {
	canWrite, debugInfo := h.service.CanWriteDebug()
	if !canWrite {
		c.JSON(http.StatusForbidden, gin.H{"error": "pricelist write is not allowed", "debug": debugInfo})
		return
	}

	var req struct {
		Source string `json:"source"`
		Items  []struct {
			LotName string  `json:"lot_name"`
			Price   float64 `json:"price"`
		} `json:"items"`
	}
	if err := c.ShouldBindJSON(&req); err != nil && !errors.Is(err, io.EOF) {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	source := string(models.NormalizePricelistSource(req.Source))
	createdBy := h.dbUser
	if strings.TrimSpace(createdBy) == "" {
		createdBy = "unknown"
	}
	items := make([]pricelist.CreateItemInput, 0, len(req.Items))
	for _, item := range req.Items {
		items = append(items, pricelist.CreateItemInput{LotName: item.LotName, Price: item.Price})
	}

	c.Header("Content-Type", "text/event-stream")
	c.Header("Cache-Control", "no-cache")
	c.Header("Connection", "keep-alive")

	flusher, ok := c.Writer.(http.Flusher)
	if !ok {
		pl, err := h.service.CreateForSourceWithProgress(createdBy, source, items, nil)
		if err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
			return
		}
		c.JSON(http.StatusCreated, pl)
		return
	}

	send := func(payload gin.H) { c.SSEvent("progress", payload); flusher.Flush() }
	send(gin.H{"current": 0, "total": 100, "status": "starting", "message": "Запуск..."})
	pl, err := h.service.CreateForSourceWithProgress(createdBy, source, items, func(p pricelist.CreateProgress) {
		send(gin.H{"current": p.Current, "total": p.Total, "status": p.Status, "message": p.Message, "updated": p.Updated, "errors": p.Errors, "lot_name": p.LotName})
	})
	if err != nil {
		send(gin.H{"status": "error", "message": err.Error()})
		return
	}
	send(gin.H{"current": 100, "total": 100, "status": "completed", "message": "Готово", "pricelist": pl})
}

func (h *PricelistHandler) Delete(c *gin.Context) {
	canWrite, debugInfo := h.service.CanWriteDebug()
	if !canWrite {
		c.JSON(http.StatusForbidden, gin.H{"error": "pricelist write is not allowed", "debug": debugInfo})
		return
	}
	id, err := strconv.ParseUint(c.Param("id"), 10, 32)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid pricelist ID"})
		return
	}
	if err := h.service.Delete(uint(id)); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"message": "pricelist deleted"})
}

func (h *PricelistHandler) SetActive(c *gin.Context) {
	canWrite, debugInfo := h.service.CanWriteDebug()
	if !canWrite {
		c.JSON(http.StatusForbidden, gin.H{"error": "pricelist write is not allowed", "debug": debugInfo})
		return
	}
	id, err := strconv.ParseUint(c.Param("id"), 10, 32)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid pricelist ID"})
		return
	}
	var req struct {
		IsActive bool `json:"is_active"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	if err := h.service.SetActive(uint(id), req.IsActive); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"message": "updated", "is_active": req.IsActive})
}

func (h *PricelistHandler) GetItems(c *gin.Context) {
	id, err := strconv.ParseUint(c.Param("id"), 10, 32)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid pricelist ID"})
		return
	}
	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
	perPage, _ := strconv.Atoi(c.DefaultQuery("per_page", "50"))
	search := c.Query("search")
	items, total, err := h.service.GetItems(uint(id), page, perPage, search)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"items": items, "total": total, "page": page, "per_page": perPage})
}

func (h *PricelistHandler) GetLotNames(c *gin.Context) {
	id, err := strconv.ParseUint(c.Param("id"), 10, 32)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid pricelist ID"})
		return
	}
	lotNames, err := h.service.GetLotNames(uint(id))
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"lot_names": lotNames, "total": len(lotNames)})
}

func (h *PricelistHandler) CanWrite(c *gin.Context) {
	canWrite, debugInfo := h.service.CanWriteDebug()
	c.JSON(http.StatusOK, gin.H{"can_write": canWrite, "debug": debugInfo})
}

func (h *PricelistHandler) GetLatest(c *gin.Context) {
	source := string(models.NormalizePricelistSource(c.DefaultQuery("source", string(models.PricelistSourceEstimate))))
	pl, err := h.service.GetLatestActiveBySource(source)
	if err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "no pricelists available"})
		return
	}
	c.JSON(http.StatusOK, pl)
}