package test

import (
	"context"
	"math"
	"strings"
	"testing"

	"github.com/glebarez/sqlite"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"

	commonRepo "gitlab.com/mbugroup/lti-api.git/internal/common/repository"
	commonSvc "gitlab.com/mbugroup/lti-api.git/internal/common/service"
	entity "gitlab.com/mbugroup/lti-api.git/internal/entities"
	rProductWarehouse "gitlab.com/mbugroup/lti-api.git/internal/modules/inventory/product-warehouses/repositories"
	"gitlab.com/mbugroup/lti-api.git/internal/utils"
	"gitlab.com/mbugroup/lti-api.git/internal/utils/fifo"
)

// Test Transfer FIFO with Purchase as initial stockable
func TestTransferFIFO_PurchaseToTransfer(t *testing.T) {
	db, fifoSvc := setupTransferFIFOTest(t)
	ctx := context.Background()

	// Setup warehouses
	sourcePW := createProductWarehouseRow(t, db, 100) // 100 qty from purchase
	destPW := createProductWarehouseRow(t, db, 0)     // 0 qty initially

	// Step 1: Simulate Purchase - Replenish stock to source warehouse
	purchaseStockableKey := fifo.StockableKey("PURCHASE_ITEMS")
	if _, err := fifoSvc.Replenish(ctx, commonSvc.StockReplenishRequest{
		StockableKey:       purchaseStockableKey,
		StockableID:        1, // PurchaseItem ID
		ProductWarehouseID: sourcePW.Id,
		Quantity:           100,
	}); err != nil {
		t.Fatalf("Failed to replenish from purchase: %v", err)
	}

	// Verify source warehouse has stock
	assertWarehouseQuantity(t, db, sourcePW.Id, 100)
	assertAllocationCount(t, db, 1) // 1 allocation from purchase

	// Step 2: Create Transfer - will consume from source (usable) and replenish to dest (stockable)

	// Register Transfer as Usable (source warehouse - STOCK_TRANSFER_OUT)
	transferUsableKey := fifo.UsableKey("STOCK_TRANSFER_OUT")
	if err := fifoSvc.RegisterUsable(fifo.UsableConfig{
		Key:   transferUsableKey,
		Table: "stock_transfer_details",
		Columns: fifo.UsableColumns{
			ID:                 "id",
			ProductWarehouseID: "source_product_warehouse_id",
			UsageQuantity:      "usage_qty",
			PendingQuantity:    "pending_qty",
			CreatedAt:          "created_at",
		},
	}); err != nil && !strings.Contains(strings.ToLower(err.Error()), "already registered") {
		t.Fatalf("Failed to register STOCK_TRANSFER_OUT as Usable: %v", err)
	}

	// Register Transfer as Stockable (destination warehouse - STOCK_TRANSFER_IN)
	transferStockableKey := fifo.StockableKey("STOCK_TRANSFER_IN")
	if err := fifoSvc.RegisterStockable(fifo.StockableConfig{
		Key:   transferStockableKey,
		Table: "stock_transfer_details",
		Columns: fifo.StockableColumns{
			ID:                 "id",
			ProductWarehouseID: "dest_product_warehouse_id",
			TotalQuantity:      "total_qty",
			TotalUsedQuantity:  "total_used",
			CreatedAt:          "created_at",
		},
	}); err != nil && !strings.Contains(strings.ToLower(err.Error()), "already registered") {
		t.Fatalf("Failed to register STOCK_TRANSFER_IN as Stockable: %v", err)
	}

	// Create transfer detail record
	transferDetail := entity.StockTransferDetail{
		Id:                       1,
		StockTransferId:          1,
		ProductId:                1,
		SourceProductWarehouseID:  uint64Ptr(uint64(sourcePW.Id)),
		DestProductWarehouseID:   uint64Ptr(uint64(destPW.Id)),
		UsageQty:                 0,
		PendingQty:               0,
		TotalQty:                 0,
		TotalUsed:                0,
	}
	transferDetailID := uint(transferDetail.Id)
	if err := db.Create(&transferDetail).Error; err != nil {
		t.Fatalf("Failed to create transfer detail: %v", err)
	}

	transferQty := 50.0

	// Consume from source warehouse (STOCK_TRANSFER_OUT)
	consumeResult, err := fifoSvc.Consume(ctx, commonSvc.StockConsumeRequest{
		UsableKey:          "STOCK_TRANSFER_OUT",
		UsableID:           transferDetailID,
		ProductWarehouseID: sourcePW.Id,
		Quantity:           transferQty,
		AllowPending:       false, // Don't allow pending
	})
	if err != nil {
		t.Fatalf("Failed to consume from source warehouse: %v", err)
	}

	// Verify consumption
	if mathAbs(consumeResult.UsageQuantity-transferQty) > 1e-6 {
		t.Fatalf("Expected usage quantity %.2f, got %.2f", transferQty, consumeResult.UsageQuantity)
	}
	if mathAbs(consumeResult.PendingQuantity) > 1e-6 {
		t.Fatalf("Expected pending quantity 0, got %.2f", consumeResult.PendingQuantity)
	}

	// Update transfer detail usable fields
	if err := db.Model(&entity.StockTransferDetail{}).
		Where("id = ?", transferDetail.Id).
		Updates(map[string]interface{}{
			"usage_qty":   consumeResult.UsageQuantity,
			"pending_qty": consumeResult.PendingQuantity,
		}).Error; err != nil {
		t.Fatalf("Failed to update transfer detail usable fields: %v", err)
	}

	// Verify source warehouse decreased
	assertWarehouseQuantity(t, db, sourcePW.Id, 50) // 100 - 50 = 50

	// Verify allocation updated - should have 50 allocated to transfer
	allocations := fetchAllocationsByUsable(t, db, "STOCK_TRANSFER_OUT", transferDetailID)
	if len(allocations) != 1 {
		t.Fatalf("Expected 1 allocation, got %d", len(allocations))
	}
	if mathAbs(allocations[0].Qty-transferQty) > 1e-6 {
		t.Fatalf("Expected allocation qty %.2f, got %.2f", transferQty, allocations[0].Qty)
	}

	// Replenish to destination warehouse (STOCK_TRANSFER_IN)
	note := "Transfer #1"
	replenishResult, err := fifoSvc.Replenish(ctx, commonSvc.StockReplenishRequest{
		StockableKey:       "STOCK_TRANSFER_IN",
		StockableID:        transferDetailID,
		ProductWarehouseID: destPW.Id,
		Quantity:           transferQty,
		Note:               &note,
	})
	if err != nil {
		t.Fatalf("Failed to replenish to destination warehouse: %v", err)
	}

	// Verify replenishment
	if mathAbs(replenishResult.AddedQuantity-transferQty) > 1e-6 {
		t.Fatalf("Expected added quantity %.2f, got %.2f", transferQty, replenishResult.AddedQuantity)
	}

	// Update transfer detail stockable fields
	if err := db.Model(&entity.StockTransferDetail{}).
		Where("id = ?", transferDetail.Id).
		Updates(map[string]interface{}{
			"total_qty": replenishResult.AddedQuantity,
		}).Error; err != nil {
		t.Fatalf("Failed to update transfer detail stockable fields: %v", err)
	}

	// Verify destination warehouse increased
	assertWarehouseQuantity(t, db, destPW.Id, transferQty)

	// Verify new stockable allocation created
	stockableAllocations := fetchAllocationsByStockable(t, db, "STOCK_TRANSFER_IN", transferDetailID)
	if len(stockableAllocations) != 1 {
		t.Fatalf("Expected 1 stockable allocation, got %d", len(stockableAllocations))
	}
	if mathAbs(stockableAllocations[0].Qty-transferQty) > 1e-6 {
		t.Fatalf("Expected stockable allocation qty %.2f, got %.2f", transferQty, stockableAllocations[0].Qty)
	}

	t.Logf("✅ Transfer FIFO test passed:")
	t.Logf("  - Source warehouse: 100 → 50 (consumed %d)", int(transferQty))
	t.Logf("  - Destination warehouse: 0 → %d (replenished)", int(transferQty))
	t.Logf("  - Usable allocation: %.2f allocated to transfer", allocations[0].Qty)
	t.Logf("  - Stockable allocation: %.2f available at destination", stockableAllocations[0].Qty)
}

// Setup function for transfer FIFO test
func setupTransferFIFOTest(t *testing.T) (*gorm.DB, commonSvc.FifoService) {
	t.Helper()

	db, err := gorm.Open(sqlite.Open("file::memory:?cache=shared"), &gorm.Config{
		Logger: logger.Default.LogMode(logger.Silent),
	})
	if err != nil {
		t.Fatalf("open db: %v", err)
	}

	if err := db.AutoMigrate(
		&entity.ProductWarehouse{},
		&entity.StockAllocation{},
		&entity.StockTransferDetail{},
	); err != nil {
		t.Fatalf("auto migrate entities: %v", err)
	}

	stockAllocRepo := commonRepo.NewStockAllocationRepository(db)
	productWarehouseRepo := rProductWarehouse.NewProductWarehouseRepository(db)
	fifoSvc := commonSvc.NewFifoService(db, stockAllocRepo, productWarehouseRepo, utils.Log)

	// Register Purchase as Stockable
	purchaseStockableKey := fifo.StockableKey("PURCHASE_ITEMS")
	if err := fifoSvc.RegisterStockable(fifo.StockableConfig{
		Key:   purchaseStockableKey,
		Table: "purchase_items",
		Columns: fifo.StockableColumns{
			ID:                 "id",
			ProductWarehouseID: "product_warehouse_id",
			TotalQuantity:      "total_qty",
			TotalUsedQuantity:  "total_used",
			CreatedAt:          "created_at",
		},
	}); err != nil && !strings.Contains(strings.ToLower(err.Error()), "already registered") {
		t.Fatalf("register purchase stockable: %v", err)
	}

	return db, fifoSvc
}

// Helper functions

func createProductWarehouseRow(t *testing.T, db *gorm.DB, qty float64) entity.ProductWarehouse {
	t.Helper()
	pw := entity.ProductWarehouse{
		ProductId:   1,
		WarehouseId: 1,
		Quantity:    qty,
	}
	if err := db.Create(&pw).Error; err != nil {
		t.Fatalf("create product warehouse: %v", err)
	}
	return pw
}

func assertWarehouseQuantity(t *testing.T, db *gorm.DB, pwID uint, expected float64) {
	t.Helper()
	var pw entity.ProductWarehouse
	if err := db.First(&pw, pwID).Error; err != nil {
		t.Fatalf("fetch product warehouse %d: %v", pwID, err)
	}
	if mathAbs(pw.Quantity-expected) > 1e-6 {
		t.Fatalf("expected warehouse quantity %.2f, got %.2f", expected, pw.Quantity)
	}
}

func assertAllocationCount(t *testing.T, db *gorm.DB, expected int) {
	t.Helper()
	var count int64
	if err := db.Model(&entity.StockAllocation{}).Count(&count).Error; err != nil {
		t.Fatalf("count allocations: %v", err)
	}
	if int(count) != expected {
		t.Fatalf("expected %d allocations, got %d", expected, count)
	}
}

func fetchAllocationsByUsable(t *testing.T, db *gorm.DB, usableType string, usableID uint) []entity.StockAllocation {
	t.Helper()
	var allocations []entity.StockAllocation
	if err := db.Where("usable_type = ? AND usable_id = ?", usableType, usableID).
		Find(&allocations).Error; err != nil {
		t.Fatalf("fetch allocations by usable: %v", err)
	}
	return allocations
}

func fetchAllocationsByStockable(t *testing.T, db *gorm.DB, stockableType string, stockableID uint) []entity.StockAllocation {
	t.Helper()
	var allocations []entity.StockAllocation
	if err := db.Where("stockable_type = ? AND stockable_id = ?", stockableType, stockableID).
		Find(&allocations).Error; err != nil {
		t.Fatalf("fetch allocations by stockable: %v", err)
	}
	return allocations
}

func floatPtr(f float64) *float64 {
	return &f
}

func uint64Ptr(u uint64) *uint64 {
	return &u
}

func mathAbs(f float64) float64 {
	return math.Abs(f)
}

func sanitizeKey(name string) string {
	return strings.Map(func(r rune) rune {
		if (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z') || (r >= '0' && r <= '9') {
			return r
		}
		return '_'
	}, name)
}