import { and, eq, ne } from "drizzle-orm";
import {
  assertCircuitUpdateProjectCommand,
  createCircuitUpdateProjectCommand,
  type CircuitUpdateField,
  type CircuitUpdatePatch,
  type CircuitUpdateValues,
} from "../../domain/models/circuit-project-command.model.js";
import type {
  CircuitProjectCommandStore,
  ExecuteCircuitUpdateCommandInput,
} from "../../domain/ports/circuit-project-command.store.js";
import type { AppDatabase } from "../database-context.js";
import { circuitLists } from "../schema/circuit-lists.js";
import { circuitSections } from "../schema/circuit-sections.js";
import { circuits } from "../schema/circuits.js";
import {
  toCircuitPatchValues,
  type CircuitPatchPersistenceInput,
} from "./circuit.persistence.js";
import { executeProjectCommandTransactionWithAppliedForward } from "./project-command-transaction.persistence.js";
import { resolveCircuitVoltage } from "./project-voltage.persistence.js";
import { circuitDeviceRows } from "../schema/circuit-device-rows.js";

type CircuitRow = typeof circuits.$inferSelect;

export class CircuitProjectCommandRepository
  implements CircuitProjectCommandStore
{
  constructor(private readonly database: AppDatabase) {}

  executeUpdate(input: ExecuteCircuitUpdateCommandInput) {
    assertCircuitUpdateProjectCommand(input.command);

    return executeProjectCommandTransactionWithAppliedForward(
      this.database,
      input,
      (tx) => this.applyCommand(tx, input)
    );
  }

  private applyCommand(
    tx: AppDatabase,
    input: ExecuteCircuitUpdateCommandInput
  ) {
    const current = tx
      .select()
      .from(circuits)
      .where(eq(circuits.id, input.command.payload.circuitId))
      .get();
    if (!current) {
      throw new Error("Invalid circuit id.");
    }

    const owningList = tx
      .select({ id: circuitLists.id })
      .from(circuitLists)
      .where(
        and(
          eq(circuitLists.id, current.circuitListId),
          eq(circuitLists.projectId, input.projectId)
        )
      )
      .get();
    if (!owningList) {
      throw new Error("Circuit does not belong to project.");
    }

    const patch = Object.fromEntries(
      input.command.payload.changes.map((change) => [
        change.field,
        change.value,
      ])
    ) as CircuitPatchPersistenceInput;
    this.assertSectionInCircuitList(tx, current, patch.sectionId);
    if (input.source === "user") {
      if (
        input.command.payload.changes.every(
          (change) => change.field === "voltage"
        )
      ) {
        throw new Error("Circuit voltage is derived and cannot be edited.");
      }
      const devicePhaseTypes = tx
        .select({ phaseType: circuitDeviceRows.phaseType })
        .from(circuitDeviceRows)
        .where(eq(circuitDeviceRows.circuitId, current.id))
        .all()
        .map((row) => row.phaseType);
      const derivedVoltage = resolveCircuitVoltage(
        tx,
        input.projectId,
        patch.sectionId ?? current.sectionId,
        devicePhaseTypes
      );
      if (derivedVoltage === current.voltage) {
        delete patch.voltage;
      } else {
        patch.voltage = derivedVoltage;
      }
    }
    this.assertUniqueEquipmentIdentifier(
      tx,
      current,
      patch.equipmentIdentifier
    );

    const appliedForward = createCircuitUpdateProjectCommand(
      current.id,
      patch as CircuitUpdatePatch
    );
    const inversePatch = Object.fromEntries(
      appliedForward.payload.changes.map((change) => [
        change.field,
        getCircuitFieldValue(current, change.field),
      ])
    ) as CircuitUpdatePatch;
    const inverse = createCircuitUpdateProjectCommand(
      current.id,
      inversePatch
    );

    const update = tx
      .update(circuits)
      .set(toCircuitPatchValues(patch))
      .where(eq(circuits.id, current.id))
      .run();
    if (update.changes !== 1) {
      throw new Error("Circuit changed before command execution.");
    }

    return { forward: appliedForward, inverse };
  }

  private assertSectionInCircuitList(
    database: AppDatabase,
    circuit: CircuitRow,
    sectionId: string | undefined
  ) {
    if (sectionId === undefined || sectionId === circuit.sectionId) {
      return;
    }
    const section = database
      .select({ id: circuitSections.id })
      .from(circuitSections)
      .where(
        and(
          eq(circuitSections.id, sectionId),
          eq(circuitSections.circuitListId, circuit.circuitListId)
        )
      )
      .get();
    if (!section) {
      throw new Error("Section does not belong to circuit list.");
    }
  }

  private assertUniqueEquipmentIdentifier(
    database: AppDatabase,
    circuit: CircuitRow,
    equipmentIdentifier: string | undefined
  ) {
    if (
      equipmentIdentifier === undefined ||
      equipmentIdentifier === circuit.equipmentIdentifier
    ) {
      return;
    }
    const duplicate = database
      .select({ id: circuits.id })
      .from(circuits)
      .where(
        and(
          eq(circuits.circuitListId, circuit.circuitListId),
          eq(circuits.equipmentIdentifier, equipmentIdentifier),
          ne(circuits.id, circuit.id)
        )
      )
      .get();
    if (duplicate) {
      throw new Error("Duplicate equipmentIdentifier in circuit list.");
    }
  }
}

function getCircuitFieldValue<TField extends CircuitUpdateField>(
  circuit: CircuitRow,
  field: TField
): CircuitUpdateValues[TField] {
  if (field === "isReserve") {
    return Boolean(circuit.isReserve) as CircuitUpdateValues[TField];
  }
  return circuit[field] as unknown as CircuitUpdateValues[TField];
}