/**
 * Chapter settlement logic (task 8.2, req 14.1-14.5).
 *
 * After the boss dies the chapter-1 cutscene sequence is strictly:
 *
 *   princess_taken_cutscene (≤ 3s)  — optional, plays mid-fight when HP ≤ 1/2
 *   boss_killed             (≤ 2s)  — freeze-frame
 *   settlement_screen               — score + stats UI
 *
 * There is **no** rope-severing rescue event in the MVP (req 14.5), so we
 * expose a single `BANNED_RESCUE_SEQUENCE` constant the QA test asserts
 * against; any future code that tries to play it will fail the guardrail.
 */

export type CutsceneId = 'princess_taken' | 'boss_killed_freeze' | 'settlement_screen';

/** Any rescue-style cutscene ID in this set will fail CI (req 14.5). */
export const BANNED_RESCUE_SEQUENCE: ReadonlyArray<string> = Object.freeze([
    'rope_cut_rescue',
    'princess_rescued',
    'chapter_end_rescue',
]);

export interface ISettlementStats {
    totalScore: number;
    stageScore: number;
    comboCount: number;
    flawless: boolean;
    remainingTimeSec: number;
}

export interface ISettlementResult {
    stats: ISettlementStats;
    closingLine: string;
}

export class ChapterSettlement {
    private stats: ISettlementStats;

    constructor(initialStats: ISettlementStats) {
        this.stats = { ...initialStats };
    }

    public addScore(pts: number): void {
        this.stats.stageScore += pts;
        this.stats.totalScore += pts;
    }

    public registerCombo(): void {
        this.stats.comboCount++;
    }

    public markTaken(): void {
        this.stats.flawless = false;
    }

    public setRemainingTime(sec: number): void {
        this.stats.remainingTimeSec = sec;
    }

    public assertCutsceneAllowed(id: CutsceneId | string): void {
        if (BANNED_RESCUE_SEQUENCE.includes(id)) {
            throw new Error(
                `ChapterSettlement: cutscene "${id}" is explicitly banned — chapter 1 must end with the princess taken (req 14.5)`
            );
        }
    }

    public build(): ISettlementResult {
        const closing = '公主被带走，续章待续…';
        return { stats: { ...this.stats }, closingLine: closing };
    }
}