import { and, eq } from "drizzle-orm";
import {
  assertCircuitGroupRenumberProjectCommand,
  createCircuitGroupRenumberProjectCommand,
  type CircuitGroupRenumberProjectCommand,
} from "../../domain/models/circuit-group-renumber-project-command.model.js";
import type { CircuitGroupRenumberProjectCommandStore } from "../../domain/ports/circuit-group-renumber-project-command.store.js";
import type { ExecuteCircuitGroupRenumberCommandInput } from "../../domain/ports/circuit-group-renumber-project-command.store.js";
import type { CircuitGroupRenumberPlan } from "../../domain/services/circuit-group-renumbering.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 { distributionBoardComponents } from "../schema/distribution-board-components.js";
import { executeProjectCommandTransaction } from "./project-command-transaction.persistence.js";

export class CircuitGroupRenumberProjectCommandRepository
  implements CircuitGroupRenumberProjectCommandStore
{
  constructor(private readonly database: AppDatabase) {}

  execute(input: ExecuteCircuitGroupRenumberCommandInput) {
    assertCircuitGroupRenumberProjectCommand(input.command);
    return executeProjectCommandTransaction(
      this.database,
      input,
      (tx) => this.applyCommand(tx, input.projectId, input.command)
    );
  }

  private applyCommand(
    database: AppDatabase,
    projectId: string,
    command: CircuitGroupRenumberProjectCommand
  ) {
    const { circuitListId, groups } = command.payload;
    this.assertCurrentState(database, projectId, circuitListId, groups);
    const inverse = createCircuitGroupRenumberProjectCommand(
      circuitListId,
      invertPlan(groups)
    );
    const occupiedIdentifiers = new Set(
      [
        ...database
          .select({ value: circuits.equipmentIdentifier })
          .from(circuits)
          .where(eq(circuits.circuitListId, circuitListId))
          .all(),
        ...database
          .select({ value: distributionBoardComponents.equipmentIdentifier })
          .from(distributionBoardComponents)
          .where(
            eq(distributionBoardComponents.circuitListId, circuitListId)
          )
          .all(),
      ].map(({ value }) => normalizeIdentifier(value))
    );
    const temporaryIdentifiers = new Map<string, string>();
    for (const group of groups) {
      for (const assignment of [
        ...group.circuits.map((entry) => ({
          id: entry.circuitId,
          expected: entry.expectedEquipmentIdentifier,
          table: "circuit" as const,
        })),
        ...group.components.map((entry) => ({
          id: entry.componentId,
          expected: entry.expectedEquipmentIdentifier,
          table: "component" as const,
        })),
      ]) {
        const key = `${assignment.table}:${assignment.id}`;
        const temporary = createTemporaryIdentifier(
          key,
          occupiedIdentifiers
        );
        temporaryIdentifiers.set(key, temporary);
        this.updateEntityIdentifier(
          database,
          assignment.table,
          assignment.id,
          circuitListId,
          assignment.expected,
          temporary
        );
      }
    }

    const occupiedPrefixes = new Set(
      database
        .select({ prefix: circuitSections.prefix })
        .from(circuitSections)
        .where(eq(circuitSections.circuitListId, circuitListId))
        .all()
        .map(({ prefix }) => prefix)
    );
    const temporaryPrefixes = new Map<string, string>();
    for (const group of groups) {
      const temporaryPrefix = createTemporaryValue(
        `__tmp_group_prefix_${group.groupId}`,
        occupiedPrefixes
      );
      temporaryPrefixes.set(group.groupId, temporaryPrefix);
      const updated = database
        .update(circuitSections)
        .set({ groupNumber: null, prefix: temporaryPrefix })
        .where(
          and(
            eq(circuitSections.id, group.groupId),
            eq(circuitSections.circuitListId, circuitListId),
            eq(circuitSections.groupNumber, group.expectedGroupNumber),
            eq(circuitSections.prefix, group.expectedPrefix)
          )
        )
        .run();
      if (updated.changes !== 1) {
        throw new Error("Circuit group changed during renumbering.");
      }
    }

    for (const group of groups) {
      const updated = database
        .update(circuitSections)
        .set({
          groupNumber: group.targetGroupNumber,
          prefix: group.targetPrefix,
        })
        .where(
          and(
            eq(circuitSections.id, group.groupId),
            eq(circuitSections.circuitListId, circuitListId),
            eq(circuitSections.prefix, temporaryPrefixes.get(group.groupId)!)
          )
        )
        .run();
      if (updated.changes !== 1) {
        throw new Error("Circuit group changed during final renumbering.");
      }
    }

    for (const group of groups) {
      for (const assignment of group.circuits) {
        this.updateEntityIdentifier(
          database,
          "circuit",
          assignment.circuitId,
          circuitListId,
          temporaryIdentifiers.get(`circuit:${assignment.circuitId}`)!,
          assignment.targetEquipmentIdentifier
        );
      }
      for (const assignment of group.components) {
        this.updateEntityIdentifier(
          database,
          "component",
          assignment.componentId,
          circuitListId,
          temporaryIdentifiers.get(`component:${assignment.componentId}`)!,
          assignment.targetEquipmentIdentifier
        );
      }
    }
    return inverse;
  }

  private assertCurrentState(
    database: AppDatabase,
    projectId: string,
    circuitListId: string,
    groups: CircuitGroupRenumberPlan["groups"]
  ) {
    const list = database
      .select({ projectId: circuitLists.projectId })
      .from(circuitLists)
      .where(eq(circuitLists.id, circuitListId))
      .get();
    if (!list || list.projectId !== projectId) {
      throw new Error("Circuit-group list does not belong to project.");
    }
    const selectedIds = new Set(groups.map((group) => group.groupId));
    const allGroups = database
      .select()
      .from(circuitSections)
      .where(eq(circuitSections.circuitListId, circuitListId))
      .all();
    for (const group of groups) {
      const current = allGroups.find((entry) => entry.id === group.groupId);
      if (
        !current ||
        current.category !== group.category ||
        current.groupNumber !== group.expectedGroupNumber ||
        current.prefix !== group.expectedPrefix
      ) {
        throw new Error("Circuit group changed before renumbering.");
      }
      const currentCircuits = database
        .select({
          id: circuits.id,
          equipmentIdentifier: circuits.equipmentIdentifier,
        })
        .from(circuits)
        .where(eq(circuits.sectionId, group.groupId))
        .all();
      const currentComponents = database
        .select({
          id: distributionBoardComponents.id,
          equipmentIdentifier:
            distributionBoardComponents.equipmentIdentifier,
        })
        .from(distributionBoardComponents)
        .where(eq(distributionBoardComponents.sectionId, group.groupId))
        .all();
      if (
        !matchesAssignments(currentCircuits, group.circuits, "circuitId") ||
        !matchesAssignments(
          currentComponents,
          group.components,
          "componentId"
        )
      ) {
        throw new Error(
          "Circuit-group renumber must include every unchanged child."
        );
      }
    }
    for (const group of groups) {
      if (
        allGroups.some(
          (entry) =>
            !selectedIds.has(entry.id) &&
            entry.category === group.category &&
            entry.groupNumber === group.targetGroupNumber
        )
      ) {
        throw new Error(
          "Target group number belongs to an unchanged group."
        );
      }
    }
  }

  private updateEntityIdentifier(
    database: AppDatabase,
    table: "circuit" | "component",
    id: string,
    circuitListId: string,
    expected: string,
    target: string
  ) {
    const schema =
      table === "circuit" ? circuits : distributionBoardComponents;
    const updated = database
      .update(schema)
      .set({ equipmentIdentifier: target })
      .where(
        and(
          eq(schema.id, id),
          eq(schema.circuitListId, circuitListId),
          eq(schema.equipmentIdentifier, expected)
        )
      )
      .run();
    if (updated.changes !== 1) {
      throw new Error(
        "Circuit-group child changed during renumbering."
      );
    }
  }
}

function matchesAssignments<
  TAssignment extends {
    expectedEquipmentIdentifier: string;
  },
>(
  current: Array<{ id: string; equipmentIdentifier: string }>,
  assignments: TAssignment[],
  idField: keyof TAssignment
) {
  if (current.length !== assignments.length) {
    return false;
  }
  const currentById = new Map(current.map((entry) => [entry.id, entry]));
  return assignments.every((assignment) => {
    const id = assignment[idField];
    return (
      typeof id === "string" &&
      currentById.get(id)?.equipmentIdentifier ===
        assignment.expectedEquipmentIdentifier
    );
  });
}

function invertPlan(
  groups: CircuitGroupRenumberPlan["groups"]
): CircuitGroupRenumberPlan {
  return {
    groups: groups.map((group) => ({
      ...group,
      expectedGroupNumber: group.targetGroupNumber,
      targetGroupNumber: group.expectedGroupNumber,
      expectedPrefix: group.targetPrefix,
      targetPrefix: group.expectedPrefix,
      circuits: group.circuits.map((circuit) => ({
        ...circuit,
        expectedEquipmentIdentifier:
          circuit.targetEquipmentIdentifier,
        targetEquipmentIdentifier:
          circuit.expectedEquipmentIdentifier,
      })),
      components: group.components.map((component) => ({
        ...component,
        expectedEquipmentIdentifier:
          component.targetEquipmentIdentifier,
        targetEquipmentIdentifier:
          component.expectedEquipmentIdentifier,
      })),
    })),
  };
}

function createTemporaryIdentifier(
  key: string,
  occupied: Set<string>
) {
  return createTemporaryValue(
    `__tmp_group_renumber_${key.replace(":", "_")}`,
    occupied,
    normalizeIdentifier
  );
}

function createTemporaryValue(
  base: string,
  occupied: Set<string>,
  normalize: (value: string) => string = (value) => value
) {
  let candidate = base;
  while (occupied.has(normalize(candidate))) {
    candidate += "_";
  }
  occupied.add(normalize(candidate));
  return candidate;
}

function normalizeIdentifier(value: string) {
  return value.trim().toLocaleLowerCase();
}