package handlers

import (
	"crypto/sha256"
	"fmt"
	"net/http"

	"github.com/flatrender/render-svc/internal/db"
	"github.com/flatrender/render-svc/internal/middleware"
	"github.com/flatrender/render-svc/internal/models"
	"github.com/gin-gonic/gin"
	"github.com/google/uuid"
)

type SnapshotHandler struct {
	store *db.Store
}

func NewSnapshotHandler(store *db.Store) *SnapshotHandler {
	return &SnapshotHandler{store: store}
}

// POST /v1/snapshots
func (h *SnapshotHandler) Create(c *gin.Context) {
	userID := middleware.GetUserID(c)
	tenantID := middleware.GetTenantID(c)

	var req models.SnapshotCreateRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: err.Error()})
		return
	}

	// Deterministic cache key from inputs
	hash := fmt.Sprintf("%x", sha256.Sum256([]byte(
		fmt.Sprintf("%s:%s:%d", req.SavedProjectID, req.SceneKey, req.FrameNumber),
	)))

	// Check cache first
	cached, err := h.store.GetCachedSnapshot(c.Request.Context(),
		req.SavedProjectID, req.SceneKey, req.FrameNumber, hash)
	if err == nil && cached != nil {
		c.JSON(http.StatusAccepted, gin.H{
			"snapshot_id":   cached.ID,
			"status":        "Cached",
			"image_url":     cached.ImageURL,
			"thumbnail_url": cached.ThumbnailURL,
			"expires_at":    cached.ExpiresAt,
		})
		return
	}

	snap, err := h.store.CreateSnapshot(c.Request.Context(), userID, tenantID, &req, hash)
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.APIError{Code: "internal_error", Message: err.Error()})
		return
	}
	c.JSON(http.StatusAccepted, gin.H{
		"snapshot_id":   snap.ID,
		"status":        "Pending",
		"image_url":     nil,
		"thumbnail_url": nil,
		"expires_at":    snap.ExpiresAt,
	})
}

// GET /v1/snapshots/:snapshot_id
func (h *SnapshotHandler) Get(c *gin.Context) {
	snapID, err := uuid.Parse(c.Param("snapshot_id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, models.APIError{Code: "bad_request", Message: "invalid snapshot_id"})
		return
	}
	snap, err := h.store.GetSnapshotByID(c.Request.Context(), snapID)
	if err != nil {
		c.JSON(http.StatusNotFound, models.APIError{Code: "not_found", Message: err.Error()})
		return
	}
	c.JSON(http.StatusOK, snap)
}