import tutorialMission from '../assets/data/missions/mission_tutorial_01.json' with { type: 'json' };
import { narrativeManager } from './NarrativeManager.js';

/**
 * MissionManager.js
 * Manages campaign progression, mission selection, narrative triggers, and objective tracking.
 */
export class MissionManager {
    constructor() {
        // Campaign State
        this.activeMissionId = null;
        this.completedMissions = new Set();
        this.missionRegistry = new Map();

        // Active Run State
        this.currentMissionDef = null;
        this.currentObjectives = [];

        // Register default missions
        this.registerMission(tutorialMission);
    }

    registerMission(missionDef) {
        this.missionRegistry.set(missionDef.id, missionDef);
    }

    // --- PERSISTENCE (Campaign) ---

    load(saveData) {
        this.completedMissions = new Set(saveData.completedMissions || []);
        // Default to Tutorial if history is empty
        if (this.completedMissions.size === 0) {
            this.activeMissionId = 'MISSION_TUTORIAL_01';
        }
    }

    save() {
        return {
            completedMissions: Array.from(this.completedMissions)
        };
    }

    // --- MISSION SETUP & NARRATIVE ---

    /**
     * Gets the configuration for the currently selected mission.
     */
    getActiveMission() {
        if (!this.activeMissionId) return this.missionRegistry.get('MISSION_TUTORIAL_01');
        return this.missionRegistry.get(this.activeMissionId);
    }

    /**
     * Prepares the manager for a new run.
     * Resets objectives and prepares narrative hooks.
     */
    setupActiveMission() {
        const mission = this.getActiveMission();
        this.currentMissionDef = mission;
        
        // Hydrate objectives state
        this.currentObjectives = mission.objectives.primary.map(obj => ({
            ...obj,
            current: 0,
            complete: false
        }));

        console.log(`Mission Setup: ${mission.config.title} - Objectives:`, this.currentObjectives);
    }

    /**
     * Plays the intro narrative if one exists.
     * Returns a Promise that resolves when the game should start.
     */
    async playIntro() {
        if (!this.currentMissionDef || !this.currentMissionDef.narrative || !this.currentMissionDef.narrative.intro_sequence) {
            return Promise.resolve();
        }

        return new Promise((resolve) => {
            const introId = this.currentMissionDef.narrative.intro_sequence;
            
            // Mock loader: In real app, fetch the JSON from assets/data/narrative/
            // For prototype, we'll assume narrativeManager can handle the ID or we pass a mock.
            // const narrativeData = await fetch(`assets/data/narrative/${introId}.json`).then(r => r.json());
             
            // We'll simulate the event listener logic
            const onEnd = () => {
                narrativeManager.removeEventListener('narrative-end', onEnd);
                resolve();
            };
            narrativeManager.addEventListener('narrative-end', onEnd);
            
            // Trigger the manager (Assuming it has a loader, or we modify it to accept ID)
            // For this snippet, we assume startSequence accepts data.
            // In a full implementation, you'd load the JSON here.
            console.log(`Playing Narrative Intro: ${introId}`);
            // narrativeManager.startSequence(loadedJson); 
            
            // Fallback for prototype if no JSON loader:
            setTimeout(onEnd, 100); // Instant resolve for now to prevent hanging
        });
    }

    // --- GAMEPLAY LOGIC (Objectives) ---

    /**
     * Called by GameLoop whenever a relevant event occurs.
     * @param {string} type - 'ENEMY_DEATH', 'TURN_END', etc.
     * @param {Object} data - Context data
     */
    onGameEvent(type, data) {
        if (!this.currentObjectives.length) return;

        let statusChanged = false;

        this.currentObjectives.forEach(obj => {
            if (obj.complete) return;

            // Logic for 'ELIMINATE_ALL' or 'ELIMINATE_UNIT'
            if (type === 'ENEMY_DEATH') {
                if (obj.type === 'ELIMINATE_ALL' || 
                   (obj.type === 'ELIMINATE_UNIT' && data.unitId === obj.target_def_id)) {
                    
                    obj.current++;
                    if (obj.target_count && obj.current >= obj.target_count) {
                        obj.complete = true;
                        statusChanged = true;
                    }
                }
            }
        });

        if (statusChanged) {
            this.checkVictory();
        }
    }

    checkVictory() {
        const allPrimaryComplete = this.currentObjectives.every(o => o.complete);
        if (allPrimaryComplete) {
            console.log("VICTORY! Mission Objectives Complete.");
            this.completeActiveMission();
            // Dispatch event for GameLoop to handle Victory Screen
            window.dispatchEvent(new CustomEvent('mission-victory', { detail: { missionId: this.activeMissionId }}));
        }
    }

    completeActiveMission() {
        if (this.activeMissionId) {
            this.completedMissions.add(this.activeMissionId);
            // Simple campaign logic: If Tutorial done, unlock next (Placeholder)
            if (this.activeMissionId === 'MISSION_TUTORIAL_01') {
                // this.activeMissionId = 'MISSION_ACT1_01'; 
            }
        }
    }
}