import { Bar, Course } from 'tja-parser';

export interface Factors {
    physical_density: number;
    stamina_requirement: number;
    pattern_complexity: number;
    rhythmic_complexity: number;
    reading_gimmick: number;
}

export namespace Factor {
    export function getAllNotes(course: Course): any[] {
        const notes: any[] = [];
        for (const group of course.noteGroups) {
            if (group instanceof Bar) {
                notes.push(...group.getNotes());
            }
        }
        return notes;
    }

    export function getPhysicalDensity(course: Course): number {
        const notes = getAllNotes(course);
        if (notes.length === 0) return 0;
        const bars = course.noteGroups.length;
        return notes.length / (bars || 1);
    }

    export function getStaminaRequirement(course: Course): number {
        const notes = getAllNotes(course);
        let maxStream = 0;
        let currentStream = 0;
        
        for (const note of notes) {
            if (note.type !== '0') {
                currentStream++;
            } else {
                maxStream = Math.max(maxStream, currentStream);
                currentStream = 0;
            }
        }
        return Math.max(maxStream, currentStream) / 100;
    }

    export function getPatternComplexity(course: Course): number {
        const notes = getAllNotes(course).filter(n => n.type === '1' || n.type === '2');
        let transitions = 0;
        
        for (let i = 1; i < notes.length; i++) {
            if (notes[i].type !== notes[i-1].type) {
                transitions++;
            }
        }
        return notes.length > 0 ? transitions / notes.length : 0;
    }

    export function getRhythmicComplexity(course: Course): number {
        let complexNotes = 0;
        const allNotes = getAllNotes(course);
        for (const group of course.noteGroups) {
            if (group instanceof Bar) {
                const division = group.getNotes().length;
                if (division % 4 !== 0 || division > 16) {
                    complexNotes += division;
                }
            }
        }
        return allNotes.length > 0 ? complexNotes / allNotes.length : 0;
    }

    export function getReadingGimmick(course: Course): number {
        // BPM 변화나 Scroll 변화 빈도 측정
        // tja-parser의 구조에 따라 구현 (여기서는 placeholder)
        return 0;
    }
}

export function factorize(course: Course): Factors {
    return {
        physical_density: Factor.getPhysicalDensity(course),
        stamina_requirement: Factor.getStaminaRequirement(course),
        pattern_complexity: Factor.getPatternComplexity(course),
        rhythmic_complexity: Factor.getRhythmicComplexity(course),
        reading_gimmick: Factor.getReadingGimmick(course)
    };
}