import type { Payload } from "payload";
import type { GameStructure, GameVehicle, Shipment, Vehicle } from "@/payload-types";
import { emitGameEvent } from "@/utils/event-log/emit";
import { EventTypes } from "@/utils/event-log/eventTypes";
import { notifyUser } from "@/lib/notifications";
import { checkStorageDeposit, storageViolationMessage } from "@/lib/storageRules";
import { errorMessage, type BinLogger } from "./lib/binFileLogger";

type ShipmentDoc = Shipment & {
  transportVehicle: GameVehicle & { type: Vehicle };
  origin: GameStructure;
  destination: GameStructure;
};

export async function processShipmentTick(
  payload: Payload,
  shipment: ShipmentDoc,
  log: Pick<BinLogger, "error">,
): Promise<void> {
  const now = new Date();
  const vehicle = shipment.transportVehicle;

  if (!vehicle || typeof vehicle === "number") return;

  const vehicleType = typeof vehicle.type === "object" ? vehicle.type : null;
  if (!vehicleType) return;

  const dispatchedAt = new Date(shipment.dispatchedAt!);
  const estimatedArrival = new Date(shipment.estimatedArrival!);
  const gameRules = await payload.findGlobal({ slug: "game-rules" });
  const tickIntervalMinutes = (gameRules.gameTickIntervalMinutes as number) || 10;
  const totalDurationMs = estimatedArrival.getTime() - dispatchedAt.getTime();
  const totalTicks = Math.max(1, Math.ceil(totalDurationMs / (tickIntervalMinutes * 60 * 1000)));

  const fuelPerTick = shipment.fuelCost / totalTicks;
  const currentFuelConsumed = shipment.fuelConsumed ?? 0;

  if (vehicle.currentFuel < fuelPerTick) {
    await payload.update({
      collection: "shipments",
      id: shipment.id,
      data: {
        status: "stranded",
        failureReason: "Vehicle ran out of fuel during transit.",
      },
    });

    await payload.update({
      collection: "game-vehicles",
      id: vehicle.id,
      data: { status: "damaged" },
    });

    const originId =
      typeof shipment.origin === "object" ? shipment.origin.id : (shipment.origin as number);

    await emitGameEvent(payload, {
      type: EventTypes.ShipmentFail,
      message: `Shipment "${shipment.name ?? `SHP-${shipment.id}`}" stranded — vehicle out of fuel`,
      structure: originId,
      targetCollection: "shipments",
      targetId: shipment.id,
      data: { reason: "out_of_fuel", vehicleId: vehicle.id },
    });
    return;
  }

  const newFuel = Math.max(0, vehicle.currentFuel - fuelPerTick);
  await payload.update({
    collection: "game-vehicles",
    id: vehicle.id,
    data: { currentFuel: newFuel },
  });

  const newFuelConsumed = Math.min(currentFuelConsumed + fuelPerTick, shipment.fuelCost);

  if (now >= estimatedArrival) {
    await completeShipment(payload, shipment, newFuelConsumed, log);
    return;
  }

  await payload.update({
    collection: "shipments",
    id: shipment.id,
    data: {
      fuelConsumed: newFuelConsumed,
      status: "in_transit",
    },
  });
}

async function completeShipment(
  payload: Payload,
  shipment: ShipmentDoc,
  finalFuelConsumed: number,
  log: Pick<BinLogger, "error">,
): Promise<void> {
  const vehicle = shipment.transportVehicle;
  const destinationId =
    typeof shipment.destination === "object"
      ? shipment.destination.id
      : (shipment.destination as number);
  const originId =
    typeof shipment.origin === "object" ? shipment.origin.id : (shipment.origin as number);

  const bounced: { itemId: number; amount: number; resourceName: string }[] = [];

  for (const cargoEntry of shipment.cargo ?? []) {
    const itemRef = cargoEntry.item;
    if (!itemRef || typeof itemRef === "number") continue;

    const polymorphic = itemRef as { relationTo: string; value: number | { id: number } };
    if (polymorphic.relationTo !== "resources") continue;

    const itemId = typeof polymorphic.value === "object" ? polymorphic.value.id : polymorphic.value;

    try {
      const destination = await payload.findByID({
        collection: "game-structures",
        id: destinationId,
        depth: 2,
      });

      const destType = typeof destination.type === "object" ? destination.type : null;
      if (destType) {
        const destStored = destination.storedResources ?? [];
        const destVoid = (destination as GameStructure).voidStorage ?? [];
        const currentStored = [...destStored, ...destVoid].reduce((sum, r) => {
          const resId = typeof r.resource === "object" ? r.resource.id : r.resource;
          return sum + (resId === itemId ? r.amount : 0);
        }, 0);

        const ruleCheck = checkStorageDeposit(destType, itemId, cargoEntry.amount, currentStored);

        if (!ruleCheck.allowed) {
          const resName =
            (
              await payload
                .findByID({ collection: "resources", id: itemId, depth: 0 })
                .catch(() => null)
            )?.name ?? `resource #${itemId}`;
          bounced.push({
            itemId,
            amount: cargoEntry.amount,
            resourceName: resName,
          });
          log.error(
            `Shipment "${shipment.name ?? `SHP-${shipment.id}`}" delivery rejected at destination: ${storageViolationMessage(resName, ruleCheck)}`,
          );
          continue;
        }
      }

      const existingResources = destination.storedResources ?? [];
      const existingEntry = existingResources.find((r) => {
        const resId = typeof r.resource === "object" ? r.resource.id : r.resource;
        return resId === itemId;
      });

      if (existingEntry) {
        existingEntry.amount += cargoEntry.amount;
      } else {
        existingResources.push({
          resource: itemId,
          amount: cargoEntry.amount,
          gridX: 0,
          gridY: existingResources.length,
          rotated: false,
        });
      }

      await payload.update({
        collection: "game-structures",
        id: destinationId,
        data: { storedResources: existingResources },
      });
    } catch (error) {
      log.error(`Failed to transfer cargo item ${itemId}: ${errorMessage(error)}`);
    }
  }

  await payload.update({
    collection: "game-vehicles",
    id: vehicle.id,
    data: {
      deployedAt: destinationId,
      status: "idle",
    },
  });

  if (bounced.length > 0) {
    // Return rejected cargo to the origin structure
    const origin = await payload
      .findByID({
        collection: "game-structures",
        id: originId,
        depth: 1,
      })
      .catch(() => null);

    if (origin) {
      const existingResources = [...(origin.storedResources ?? [])];
      for (const b of bounced) {
        const existingEntry = existingResources.find((r) => {
          const resId = typeof r.resource === "object" ? r.resource.id : r.resource;
          return resId === b.itemId;
        });
        if (existingEntry) {
          existingEntry.amount += b.amount;
        } else {
          existingResources.push({
            resource: b.itemId,
            amount: b.amount,
            gridX: 0,
            gridY: existingResources.length,
            rotated: false,
          });
        }
      }
      await payload.update({
        collection: "game-structures",
        id: originId,
        data: { storedResources: existingResources },
      });
    }

    await payload.update({
      collection: "shipments",
      id: shipment.id,
      data: {
        status: "failed",
        failureReason: `Destination storage rules prevented delivery: ${bounced
          .map((b) => `${b.resourceName} ×${b.amount.toLocaleString()}`)
          .join(", ")} — returned to origin.`,
        completedAt: new Date().toISOString(),
      },
    });

    await emitGameEvent(payload, {
      type: EventTypes.ShipmentFail,
      message: `Shipment "${shipment.name ?? `SHP-${shipment.id}`}" delivery rejected by destination storage rules`,
      structure: destinationId,
      targetCollection: "shipments",
      targetId: shipment.id,
      data: {
        reason: "storage_rules",
        bounced: bounced.map((b) => ({
          itemId: b.itemId,
          amount: b.amount,
          resourceName: b.resourceName,
        })),
      },
    });
    return;
  }

  await payload.update({
    collection: "shipments",
    id: shipment.id,
    data: {
      status: "completed",
      completedAt: new Date().toISOString(),
      fuelConsumed: finalFuelConsumed,
    },
  });

  await emitGameEvent(payload, {
    type: EventTypes.ShipmentComplete,
    message: `Shipment "${shipment.name ?? `SHP-${shipment.id}`}" arrived at destination`,
    structure: destinationId,
    targetCollection: "shipments",
    targetId: shipment.id,
    data: { vehicleId: vehicle.id, originId, destinationId },
  });

  // Notify the user who created the shipment (the closest thing to a recipient/owner).
  const creatorId =
    typeof shipment.createdBy === "object" && shipment.createdBy
      ? shipment.createdBy.id
      : (shipment.createdBy as number | null | undefined);
  if (creatorId != null) {
    await notifyUser(payload, {
      userId: creatorId,
      type: "shipment:completed",
      title: "Shipment completed",
      message: `Shipment "${shipment.name ?? `SHP-${shipment.id}`}" arrived at its destination.`,
      link: `/logistics/shipments/${shipment.id}`,
    });
  }

  if (shipment.autoReturn) {
    await createAutoReturnShipment(payload, shipment, vehicle as GameVehicle & { type: Vehicle });
  }
}

async function createAutoReturnShipment(
  payload: Payload,
  originalShipment: ShipmentDoc,
  vehicle: GameVehicle & { type: Vehicle },
): Promise<void> {
  const originId =
    typeof originalShipment.origin === "object"
      ? originalShipment.origin.id
      : (originalShipment.origin as number);
  const destinationId =
    typeof originalShipment.destination === "object"
      ? originalShipment.destination.id
      : (originalShipment.destination as number);

  const vehicleType = typeof vehicle.type === "object" ? vehicle.type : null;
  if (!vehicleType) return;

  const speed =
    vehicleType.maxSpeedOnRoad ?? vehicleType.maxSpeedOffRoad ?? vehicleType.maxAirspeed ?? 50;
  const rate = vehicleType.fuel?.fuelConsumptionRate ?? 1;

  const returnFuelCost = Math.ceil(originalShipment.distance * rate);
  const returnDurationMs = (originalShipment.distance / speed) * 60 * 60 * 1000;
  const now = new Date();

  if (vehicle.currentFuel < returnFuelCost) {
    await emitGameEvent(payload, {
      type: EventTypes.ShipmentFail,
      message: `Auto-return failed — insufficient fuel`,
      structure: destinationId,
      targetCollection: "game-vehicles",
      targetId: vehicle.id,
      data: { reason: "insufficient_fuel_for_return" },
    });
    return;
  }

  await payload.update({
    collection: "game-vehicles",
    id: vehicle.id,
    data: {
      currentFuel: vehicle.currentFuel - returnFuelCost,
      status: "in_transit",
      deployedAt: null,
    },
  });

  const returnShipment = await payload.create({
    collection: "shipments",
    data: {
      name: `Return: ${originalShipment.name ?? `SHP-${originalShipment.id}`}`,
      origin: destinationId,
      destination: originId,
      transportVehicle: vehicle.id,
      distance: originalShipment.distance,
      cargo: [],
      fuelCost: returnFuelCost,
      fuelConsumed: 0,
      status: "dispatched",
      dispatchedAt: now.toISOString(),
      estimatedArrival: new Date(now.getTime() + returnDurationMs).toISOString(),
      autoReturn: false,
      createdBy: originalShipment.createdBy,
    },
  });

  await emitGameEvent(payload, {
    type: EventTypes.ShipmentAutoReturn,
    message: `Vehicle auto-returning to origin`,
    structure: destinationId,
    targetCollection: "shipments",
    targetId: returnShipment.id,
    data: { vehicleId: vehicle.id, originalShipmentId: originalShipment.id },
  });
}