import { ProjectHistoryOperationUnavailableError } from "../errors/project-history-operation-unavailable.error.js";
import {
  assertCircuitDeviceRowUpdateProjectCommand,
  circuitDeviceRowUpdateCommandType,
} from "../models/circuit-device-row-project-command.model.js";
import {
  assertCircuitDeviceRowDeleteProjectCommand,
  assertCircuitDeviceRowInsertProjectCommand,
  circuitDeviceRowDeleteCommandType,
  circuitDeviceRowInsertCommandType,
} from "../models/circuit-device-row-structure-project-command.model.js";
import {
  assertCircuitUpdateProjectCommand,
  circuitUpdateCommandType,
} from "../models/circuit-project-command.model.js";
import {
  assertCircuitDeleteProjectCommand,
  assertCircuitInsertProjectCommand,
  circuitDeleteCommandType,
  circuitInsertCommandType,
} from "../models/circuit-structure-project-command.model.js";
import {
  assertSerializedProjectCommand,
  type SerializedProjectCommand,
} from "../models/project-command.model.js";
import type { CircuitDeviceRowProjectCommandStore } from "../ports/circuit-device-row-project-command.store.js";
import type { CircuitDeviceRowStructureProjectCommandStore } from "../ports/circuit-device-row-structure-project-command.store.js";
import type { CircuitProjectCommandStore } from "../ports/circuit-project-command.store.js";
import type { CircuitStructureProjectCommandStore } from "../ports/circuit-structure-project-command.store.js";
import type {
  ExecuteProjectHistoryCommandInput,
  ExecutedProjectCommand,
  ExecuteUserProjectCommandInput,
  ProjectCommandExecutor,
} from "../ports/project-command.executor.js";
import type {
  ProjectHistoryDirection,
  ProjectHistoryStore,
} from "../ports/project-history.store.js";
import type { ProjectRevisionSource } from "../ports/project-revision.store.js";

interface DispatchProjectCommandInput {
  projectId: string;
  expectedRevision: number;
  source: ProjectRevisionSource;
  description?: string;
  actorId?: string;
  historyTargetChangeSetId?: string;
  command: SerializedProjectCommand;
}

export class ProjectCommandService implements ProjectCommandExecutor {
  constructor(
    private readonly circuitStore: CircuitProjectCommandStore,
    private readonly deviceRowStore: CircuitDeviceRowProjectCommandStore,
    private readonly deviceRowStructureStore: CircuitDeviceRowStructureProjectCommandStore,
    private readonly circuitStructureStore: CircuitStructureProjectCommandStore,
    private readonly historyStore: ProjectHistoryStore
  ) {}

  executeUser(
    input: ExecuteUserProjectCommandInput
  ): ExecutedProjectCommand {
    assertExpectedRevision(input.expectedRevision);
    assertSerializedProjectCommand(input.command);
    return this.dispatch({
      ...input,
      source: "user",
      command: input.command,
    });
  }

  undo(
    input: ExecuteProjectHistoryCommandInput
  ): ExecutedProjectCommand {
    return this.executeHistory(input, "undo");
  }

  redo(
    input: ExecuteProjectHistoryCommandInput
  ): ExecutedProjectCommand {
    return this.executeHistory(input, "redo");
  }

  private executeHistory(
    input: ExecuteProjectHistoryCommandInput,
    direction: ProjectHistoryDirection
  ) {
    assertExpectedRevision(input.expectedRevision);
    const step = this.historyStore.getNextCommand(
      input.projectId,
      direction
    );
    if (!step) {
      throw new ProjectHistoryOperationUnavailableError(
        input.projectId,
        direction
      );
    }

    return this.dispatch({
      ...input,
      source: direction,
      description: `${direction === "undo" ? "Undo" : "Redo"} ${step.command.type}`,
      historyTargetChangeSetId: step.changeSetId,
      command: step.command,
    });
  }

  private dispatch(
    input: DispatchProjectCommandInput
  ): ExecutedProjectCommand {
    const revision = this.executeTypedCommand(input);
    const history = this.historyStore.getState(input.projectId);
    if (!history) {
      throw new Error("Project history disappeared after command execution.");
    }
    return { revision, history };
  }

  private executeTypedCommand(input: DispatchProjectCommandInput) {
    switch (input.command.type) {
      case circuitUpdateCommandType: {
        assertCircuitUpdateProjectCommand(input.command);
        return this.circuitStore.executeUpdate({
          ...input,
          command: input.command,
        }).revision;
      }
      case circuitDeviceRowUpdateCommandType: {
        assertCircuitDeviceRowUpdateProjectCommand(input.command);
        return this.deviceRowStore.executeUpdate({
          ...input,
          command: input.command,
        }).revision;
      }
      case circuitDeviceRowInsertCommandType: {
        assertCircuitDeviceRowInsertProjectCommand(input.command);
        return this.deviceRowStructureStore.execute({
          ...input,
          command: input.command,
        }).revision;
      }
      case circuitDeviceRowDeleteCommandType: {
        assertCircuitDeviceRowDeleteProjectCommand(input.command);
        return this.deviceRowStructureStore.execute({
          ...input,
          command: input.command,
        }).revision;
      }
      case circuitInsertCommandType: {
        assertCircuitInsertProjectCommand(input.command);
        return this.circuitStructureStore.execute({
          ...input,
          command: input.command,
        }).revision;
      }
      case circuitDeleteCommandType: {
        assertCircuitDeleteProjectCommand(input.command);
        return this.circuitStructureStore.execute({
          ...input,
          command: input.command,
        }).revision;
      }
      default:
        throw new Error(
          `Unsupported project command type: ${input.command.type}.`
        );
    }
  }
}

function assertExpectedRevision(expectedRevision: number) {
  if (
    !Number.isSafeInteger(expectedRevision) ||
    expectedRevision < 0
  ) {
    throw new Error(
      "Expected project revision must be a non-negative integer."
    );
  }
}