package com.mydreamjob.common.r01c;

import com.mydreamjob.candidatescore.CandidateDimensionScore;
import com.mydreamjob.candidatescore.CandidateOverviewStatusPolicy;
import com.mydreamjob.candidatescore.CandidateScoringCalculator;
import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;

import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.List;

import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatThrownBy;

/**
 * R01-C 特征测试：overviewStatus 聚合规则（唯一实现 {@code CandidateOverviewStatusPolicy}）。
 *
 * <p>覆盖四种状态、空集合、null、以及"可计算但分数缺失"的边界；
 * 并锁定两个入口（计算结果 / 快照）在等价输入下的产出关系。</p>
 */
class OverviewStatusPolicyCharacterizationTest {

    private static final int EXPECTED = 8;

    private static CandidateScoringCalculator.DimensionResult result(String status, String score) {
        CandidateScoringCalculator.DimensionResult r =
                new CandidateScoringCalculator.DimensionResult("EDUCATION");
        r.status = status;
        r.score = score == null ? null : new BigDecimal(score);
        return r;
    }

    private static List<CandidateScoringCalculator.DimensionResult> results(String status, String score, int n) {
        List<CandidateScoringCalculator.DimensionResult> list = new ArrayList<>();
        for (int i = 0; i < n; i++) list.add(result(status, score));
        return list;
    }

    private static CandidateDimensionScore snapshot(String status) {
        CandidateDimensionScore s = new CandidateDimensionScore();
        s.setStatus(status);
        return s;
    }

    // ── 计算结果入口 ──────────────────────────────────────────

    @Test
    @DisplayName("特征：8/8 可计算 → OK；7/8 → PARTIAL；0/8 且全 PENDING → PENDING；否则 INSUFFICIENT_DATA")
    void computedResultsFourStates() {
        assertThat(CandidateOverviewStatusPolicy.fromComputedResults(results("OK", "80", 8), EXPECTED))
                .isEqualTo("OK");
        assertThat(CandidateOverviewStatusPolicy.fromComputedResults(results("ESTIMATED", "80", 8), EXPECTED))
                .as("ESTIMATED 与 OK 同为可计算")
                .isEqualTo("OK");

        List<CandidateScoringCalculator.DimensionResult> partial = results("OK", "80", 7);
        partial.add(result("PENDING", null));
        assertThat(CandidateOverviewStatusPolicy.fromComputedResults(partial, EXPECTED)).isEqualTo("PARTIAL");

        assertThat(CandidateOverviewStatusPolicy.fromComputedResults(results("PENDING", null, 8), EXPECTED))
                .isEqualTo("PENDING");
        assertThat(CandidateOverviewStatusPolicy.fromComputedResults(results("INSUFFICIENT_DATA", null, 8), EXPECTED))
                .isEqualTo("INSUFFICIENT_DATA");
    }

    @Test
    @DisplayName("特征：OK 但分数缺失 → 不可计算（status 与 score 都必须满足）")
    void okStatusWithoutScoreIsNotComputable() {
        assertThat(CandidateOverviewStatusPolicy.fromComputedResults(results("OK", null, 8), EXPECTED))
                .isEqualTo("INSUFFICIENT_DATA");
    }

    @Test
    @DisplayName("特征：空列表 → PENDING（计算结果入口的 empty 语义）")
    void emptyComputedResultsIsPending() {
        assertThat(CandidateOverviewStatusPolicy.fromComputedResults(List.of(), EXPECTED)).isEqualTo("PENDING");
    }

    @Test
    @DisplayName("特征：null 结果列表 → NullPointerException（既有契约）")
    void nullComputedResultsThrows() {
        assertThatThrownBy(() -> CandidateOverviewStatusPolicy.fromComputedResults(null, EXPECTED))
                .isInstanceOf(NullPointerException.class);
    }

    @Test
    @DisplayName("特征：expectedDimensions 大于实际可计算数时不得判 OK")
    void expectedDimensionsGatesOk() {
        assertThat(CandidateOverviewStatusPolicy.fromComputedResults(results("OK", "80", 8), 9))
                .isEqualTo("PARTIAL");
    }

    @Test
    @DisplayName("特征：PENDING 与 INSUFFICIENT_DATA 混合 → INSUFFICIENT_DATA（非 PENDING）")
    void mixedPendingAndInsufficientIsInsufficient() {
        List<CandidateScoringCalculator.DimensionResult> mixed = new ArrayList<>();
        mixed.add(result("PENDING", null));
        mixed.add(result("INSUFFICIENT_DATA", null));
        assertThat(CandidateOverviewStatusPolicy.fromComputedResults(mixed, EXPECTED))
                .isEqualTo("INSUFFICIENT_DATA");
    }

    // ── 快照入口 ──────────────────────────────────────────────

    @Test
    @DisplayName("特征：快照入口 —— OK/ESTIMATED 全可计算 → OK；空/null → INSUFFICIENT_DATA")
    void snapshotEntryStates() {
        assertThat(CandidateOverviewStatusPolicy.fromSnapshots(
                List.of(snapshot("OK"), snapshot("ESTIMATED")))).isEqualTo("OK");
        assertThat(CandidateOverviewStatusPolicy.fromSnapshots(
                List.of(snapshot("OK"), snapshot("PENDING")))).isEqualTo("PARTIAL");
        assertThat(CandidateOverviewStatusPolicy.fromSnapshots(
                List.of(snapshot("PENDING"), snapshot("PENDING")))).isEqualTo("PENDING");
        assertThat(CandidateOverviewStatusPolicy.fromSnapshots(
                List.of(snapshot("INSUFFICIENT_DATA"), snapshot("PENDING")))).isEqualTo("INSUFFICIENT_DATA");

        assertThat(CandidateOverviewStatusPolicy.fromSnapshots(List.of())).isEqualTo("INSUFFICIENT_DATA");
        assertThat(CandidateOverviewStatusPolicy.fromSnapshots(null)).isEqualTo("INSUFFICIENT_DATA");
    }

    // ── 唯一实现门禁 ──────────────────────────────────────────

    @Test
    @DisplayName("结构门禁：overviewStatus 规则只有唯一的产出点（\"PARTIAL\" 只在该策略类出现）")
    void partialStatusHasSingleProducer() throws Exception {
        java.nio.file.Path root = java.nio.file.Path.of("src/main/java/com/mydreamjob");
        java.util.List<String> producers = new java.util.ArrayList<>();
        try (java.util.stream.Stream<java.nio.file.Path> walk = java.nio.file.Files.walk(root)) {
            for (java.nio.file.Path p : walk.filter(f -> f.toString().endsWith(".java")).toList()) {
                String src = java.nio.file.Files.readString(p);
                if (src.contains("\"PARTIAL\"")) {
                    producers.add(p.getFileName().toString());
                }
            }
        }
        assertThat(producers)
                .as("PARTIAL 只能由 CandidateOverviewStatusPolicy 产出")
                .containsExactly("CandidateOverviewStatusPolicy.java");
    }
}