import { describe, it } from "@suaveplan/testing/runner";
import * as fc from "fast-check";
import { createCommand, executeCommand } from "../../src/command/command.js";
import { CommandMerger } from "../../src/merge/command-merger.js";

interface Counter {
    value: number;
}

describe("property: CommandMerger merge associativity", () => {
    it("merged command executes to same state as executing individually", {
        timeout: 30000,
    }, () => {
        fc.assert(
            fc.property(
                fc.array(fc.integer({ min: 1, max: 10 }), {
                    minLength: 1,
                    maxLength: 15,
                }),
                (deltas) => {
                    const commands = deltas.map((d) =>
                        createCommand<Counter>(
                            "Inc",
                            (s) => ({ value: s.value + d }),
                            (s) => ({ value: s.value - d })
                        )
                    );

                    // Execute individually
                    let individual: Counter = { value: 0 };
                    for (const cmd of commands) {
                        individual = executeCommand(individual, cmd);
                    }

                    // Merge all then execute
                    const m = new CommandMerger<Counter>({
                        maxCount: commands.length + 1,
                    });
                    for (const cmd of commands) m.add(cmd);
                    const merged = m.flush();
                    const mergedResult = merged
                        ? executeCommand({ value: 0 }, merged)
                        : { value: 0 };

                    return mergedResult.value === individual.value;
                }
            ),
            { numRuns: 200 }
        );
    });
});