main.py

# ======================================================================
# --- main.py (FULL VERSION 1.7.0) ---
# ======================================================================

import os
import json
import networkx as nx
import pandas as pd
import skops.io as sio
from fastapi import FastAPI, HTTPException
from pydantic import BaseModel
from typing import List, Dict, Any

# --- IMPOR MODUL LOKAL ---
# Pastikan file explanation_builder.py dan graduation_logic.py ada di folder yang sama
from .explanation_builder import build_full_response
from .graduation_logic import predict_graduation_status

# ======================================================================
# 1. Inisialisasi Aplikasi FastAPI
# ======================================================================
app = FastAPI(
    title="GCOMPRO API Service",
    description="API untuk Prediksi Risiko Akademik, Rekomendasi Mata Kuliah, dan Cek Kelulusan Tepat Waktu.",
    version="1.7.0"
)

# ======================================================================
# 2. Struktur Data Input/Output (Pydantic Models)
# ======================================================================

# --- [APP 1] Model untuk Prediksi Risiko ---
class StudentFeatures(BaseModel):
    IPK_Terakhir: float
    IPS_Terakhir: float
    Total_SKS: int
    IPS_Tertinggi: float
    IPS_Terendah: float
    Rentang_IPS: float
    Jumlah_MK_Gagal: int
    Total_SKS_Gagal: int
    Tren_IPS_Slope: float
    Perubahan_Kinerja_Terakhir: float
    IPK_Ternormalisasi_SKS: float
    Profil_Tren: str

class PredictionExplanation(BaseModel):
    opening_line: str
    factors: List[str]
    recommendation: str

class PredictionResponse(BaseModel):
    prediction: str
    probabilities: Dict[str, float]
    explanation: PredictionExplanation

# --- [APP 2] Model untuk Rekomendasi MK ---
class RecommendationRequest(BaseModel):
    current_semester: int
    courses_passed: List[str]
    mk_pilihan_failed: List[str] = []

class PrerequisiteInfo(BaseModel):
    code: str
    name: str

class CourseRecommendation(BaseModel):
    rank: int
    code: str
    name: str
    sks: int
    semester_plan: int
    reason: str
    is_tertinggal: bool
    priority_score: float
    prerequisites: List[PrerequisiteInfo]

# --- [APP 3] Model untuk Prediksi Kelulusan (LTW) ---
class GraduationCheckRequest(BaseModel):
    current_semester: int
    total_sks_passed: int
    ipk_last_semester: float
    courses_passed: List[str] = [] # Optional, tapi disarankan diisi untuk validasi graf

class GraduationCheckResponse(BaseModel):
    status: str
    color: str
    description: str
    stats: Dict[str, Any]

# ======================================================================
# 3. Variabel Global & Database Hardcode
# ======================================================================

# Database Mata Kuliah Pilihan (Hardcoded untuk fallback nama/sks)
ELECTIVE_COURSES_DB = {
    "AAK4ABB3": {"name": "New Generation Network", "sks": 3},
    "AAK4BBB3": {"name": "Software Defined Network", "sks": 3},
    "AAK4CBB3": {"name": "Rekayasa Jaringan", "sks": 3},
    "AAK4DBB3": {"name": "Aplikasi Cyber Security", "sks": 3},
    "AAK4EBB3": {"name": "Manajemen Telekomunikasi dan Transformasi Digital", "sks": 3},
    "AAK4FBB3": {"name": "Adaptive Network", "sks": 3},
    "AAK4GBB3": {"name": "Cloud Computing", "sks": 3},
    "AAK4HBB3": {"name": "Koding dan Kompresi", "sks": 3},
    "AAK4IBB3": {"name": "Steganografi dan Watermarking", "sks": 3},
    "AAK4JBB3": {"name": "Mobile Application", "sks": 3},
    "AAK4KBB3": {"name": "Speech Signal Processing", "sks": 3},
    "AAK4LBB3": {"name": "Komunikasi Akses Wireless", "sks": 3},
    "AAK4MBB3": {"name": "Wireless Optical Communication", "sks": 3},
    "AAK4NBB3": {"name": "Broadband Optical Network", "sks": 3},
    "AAK4OBB3": {"name": "Sistem Komunikasi Satelit", "sks": 3},
    "AAK4PBB3": {"name": "Rekayasa Radio", "sks": 3},
    "AAK4QBB3": {"name": "Radar, Navigasi dan Remote Sensing", "sks": 3},
    "AAK4RBB3": {"name": "5G and Beyond", "sks": 3},
    "AAK4SBB3": {"name": "Software Defined Radio", "sks": 3},
    "AAK4TBB3": {"name": "Robotic Process Automation", "sks": 3},
    "AAK4UBB3": {"name": "Rekayasa Frekuensi Radio dalam Komunikasi Selular", "sks": 3},
    "AAK4VBB3": {"name": "Teknologi Radio Access Network (RAN)", "sks": 3},
    "AAK4WBB3": {"name": "Internet of Things: Protokol, Platform, dan AI", "sks": 3},
    "AAK4XBB3": {"name": "Jaringan Core Telekomunikasi", "sks": 3},
    "AAK4YBB3": {"name": "Ethical Hacking", "sks": 3},
    "AAK4ZBB3": {"name": "Keamanan Komunikasi Data", "sks": 3},
    "AAK47BB3": {"name": "Rekayasa Penyiaran Digital", "sks": 3}
}

# Variabel Global ML
ml_model = None
MODEL_FEATURES = [
    'IPK_Terakhir', 'IPS_Terakhir', 'Total_SKS', 'IPS_Tertinggi',
    'IPS_Terendah', 'Rentang_IPS', 'Jumlah_MK_Gagal', 'Total_SKS_Gagal',
    'Tren_IPS_Slope', 'Perubahan_Kinerja_Terakhir',
    'IPK_Ternormalisasi_SKS', 'Tren_Menaik', 'Tren_Menurun', 'Tren_Stabil'
]

# Variabel Global Graph
G = nx.DiGraph()
course_details_map = {}
prereq_map = {}
out_degree_map = {}

# --- Fungsi Pemuatan Data ---

def load_ml_model():
    """Memuat model ML dari file .skops"""
    global ml_model
    MODEL_PATH = os.path.join(os.path.dirname(__file__), "model_risiko_akademik.skops")
    print(f"Mencoba memuat model ML dari: {MODEL_PATH}")
    try:
        trusted_types = [
            "numpy.ndarray", "numpy.core.multiarray.scalar",
            "sklearn.tree._classes.DecisionTreeClassifier", "_codecs.encode",
            "joblib.numpy_pickle.NumpyArrayWrapper", "numpy.core.multiarray._reconstruct",
            "numpy.dtype", "sklearn.tree._tree.Tree"
        ]
        ml_model = sio.load(MODEL_PATH, trusted=trusted_types)
        print("Model ML berhasil dimuat.")
    except Exception as e:
        print(f"ERROR: Gagal memuat model ML dari {MODEL_PATH}: {e}")

def load_graph_data():
    """Memuat dan memproses data graf kurikulum dari JSON"""
    global G, course_details_map, prereq_map, out_degree_map
    JSON_PATH = os.path.join(os.path.dirname(__file__), "OK_matkul_graph.json")
    print(f"Mencoba memuat data graf dari: {JSON_PATH}")
    
    prereq_edge_count = 0 
    
    try:
        with open(JSON_PATH, "r") as f:
            data = json.load(f)

        for node in data["nodes"]:
            course_details_map[node["code"]] = node
            G.add_node(node["code"])

        for edge in data["edges"]:
            if edge["type"] == "prereq":
                prereq_edge_count += 1
                G.add_edge(edge["from"], edge["to"])
                if edge["to"] not in prereq_map:
                    prereq_map[edge["to"]] = []
                prereq_map[edge["to"]].append(edge["from"])

        for node_code in G.nodes():
            out_degree_map[node_code] = G.out_degree(node_code)
        
        print(f"Data graf berhasil dimuat. Total Edges: {prereq_edge_count}")
        
    except FileNotFoundError:
        print(f"ERROR: {JSON_PATH} tidak ditemukan!")
    except Exception as e:
        print(f"Error saat memuat graf: {e}")

@app.on_event("startup")
def on_startup():
    load_ml_model()
    load_graph_data()

# ======================================================================
# 4. Helper Functions (Business Logic)
# ======================================================================

def get_recommendations_logic(current_semester: int, courses_passed_list: List[str], mk_pilihan_failed_list: List[str]) -> List[Dict[str, Any]]:
    """Logika utama untuk rekomendasi mata kuliah."""
    passed_set = set(courses_passed_list)
    all_courses_set = set(course_details_map.keys())
    not_passed_courses = all_courses_set - passed_set
    
    raw_candidates = []

    for course_code in not_passed_courses:
        prereqs = prereq_map.get(course_code, [])
        if all(p_code in passed_set for p_code in prereqs):
            details = course_details_map.get(course_code)
            if not details: continue 
            
            out_degree = out_degree_map.get(course_code, 0)
            semester = details.get("semester_plan", 1)
            
            priority_score = (out_degree / semester) if semester > 0 else 0
            
            candidate_data = details.copy()
            candidate_data["priority_score"] = priority_score
            candidate_data["is_retake_elective"] = False 
            
            raw_candidates.append(candidate_data)
    
    elective_slots = []
    regular_candidates = []
    
    for cand in raw_candidates:
        if cand["code"].startswith("MK_PILIHAN"):
            elective_slots.append(cand)
        else:
            regular_candidates.append(cand)
            
    elective_slots.sort(key=lambda x: x["semester_plan"])
    
    processed_electives = []
    failed_idx = 0
    
    while failed_idx < len(mk_pilihan_failed_list) and len(elective_slots) > 0:
        slot = elective_slots.pop(0) 
        failed_code = mk_pilihan_failed_list[failed_idx]
        
        if failed_code in ELECTIVE_COURSES_DB:
            real_name = ELECTIVE_COURSES_DB[failed_code]["name"]
            real_sks = ELECTIVE_COURSES_DB[failed_code]["sks"]
        else:
            real_name = "Mata Kuliah Pilihan (Unknown)"
            real_sks = 3

        slot["code"] = failed_code 
        slot["name"] = f"{real_name} (Mengulang)" 
        slot["sks"] = real_sks
        slot["priority_score"] += 1.0 
        slot["is_retake_elective"] = True
        
        processed_electives.append(slot)
        failed_idx += 1
        
    processed_electives.extend(elective_slots)
    final_pool = regular_candidates + processed_electives
    
    final_ranked_list = sorted(
        final_pool, 
        key=lambda x: (-x["priority_score"], x["semester_plan"])
    )
    
    return final_ranked_list

def apply_prediction_overrides(original_prediction: str, student_data: StudentFeatures) -> str:
    """Guardrails: Menerapkan aturan bisnis manual untuk override prediksi ML."""
    new_prediction = original_prediction
    
    # Aturan 1: FALSE NEGATIVE (Model optimis, padahal IPK rendah)
    if (student_data.IPK_Terakhir < 2.40 or student_data.Jumlah_MK_Gagal >= 3) and \
       (original_prediction in ["Aman", "Resiko Rendah"]):
        new_prediction = "Resiko Sedang"

    # Aturan 1B: Varian Parah
    if (student_data.IPK_Terakhir < 2.10 or student_data.Jumlah_MK_Gagal >= 5):
        new_prediction = "Resiko Tinggi"
    
    # Aturan 2: FALSE POSITIVE (Model pesimis, padahal performa naik)
    if (student_data.IPK_Terakhir > 2.75 and 
        student_data.Jumlah_MK_Gagal == 0 and 
        student_data.Tren_IPS_Slope > 0.05) and \
       (original_prediction == "Resiko Tinggi" or original_prediction == "Resiko Sedang"):
        new_prediction = "Resiko Rendah"

    # Aturan 2B: Varian Sangat Baik
    if (student_data.IPK_Terakhir > 3.25 and student_data.Jumlah_MK_Gagal == 0) and \
       (original_prediction != "Aman"):
        new_prediction = "Aman"
        
    return new_prediction

# ======================================================================
# 5. Endpoints API
# ======================================================================

@app.get("/")
def read_root():
    return {
        "message": "Selamat Datang di API Layanan Akademik Mahasiswa",
        "status": "ready",
        "endpoints": ["/predict/", "/recommend/", "/predict-graduation/"]
    }

# --- ENDPOINT 1: PREDIKSI RISIKO AKADEMIK ---
@app.post("/predict/", response_model=PredictionResponse) 
def predict_risk(student_data: StudentFeatures):
    if ml_model is None:
        raise HTTPException(status_code=503, detail="Model ML belum siap. Silakan coba lagi nanti.")

    data = student_data.dict()
    input_df = pd.DataFrame([data])
    input_encoded = pd.get_dummies(input_df, columns=['Profil_Tren'], prefix='Tren')
    input_encoded = input_encoded.reindex(columns=MODEL_FEATURES, fill_value=False)
    
    try:
        # 1. Prediksi ML Dasar
        prediction_val = ml_model.predict(input_encoded)[0] 
        prediction_proba = ml_model.predict_proba(input_encoded)
        classes = ml_model.classes_
        probabilities = dict(zip(classes, prediction_proba[0]))
        
        structured_rules = []
        
        # 2. Ekstraksi Decision Path
        if hasattr(ml_model, 'tree_'):
            try:
                tree = ml_model.tree_
                feature_names = MODEL_FEATURES
                path = ml_model.decision_path(input_encoded)
                node_indices = path.indices[path.indptr[0]:path.indptr[1]]
                
                for node_id in node_indices[:-1]: 
                    feature_index = tree.feature[node_id]
                    feature_name = feature_names[feature_index]
                    threshold = tree.threshold[node_id]
                    sample_value = input_encoded.iloc[0, feature_index]
                    
                    condition_str = "rendah" if sample_value <= threshold else "tinggi"
                    structured_rules.append({
                        "feature": feature_name,
                        "condition": condition_str,
                        "threshold": threshold,
                        "value": sample_value
                    })
            except Exception:
                pass # Lanjut tanpa path jika error

        # 3. Terapkan Override (Guardrails)
        final_prediction = apply_prediction_overrides(prediction_val, student_data)

        # 4. Sesuaikan Probabilitas dengan Override
        final_probabilities = {key: 0.0 for key in probabilities.keys()}
        if final_prediction in final_probabilities:
            final_probabilities[final_prediction] = 1.0
        else:
            first_key = next(iter(final_probabilities))
            final_probabilities[first_key] = 1.0
        
        # 5. Bangun Penjelasan Teks
        explanation_obj = build_full_response(structured_rules, final_prediction)

        return PredictionResponse(
            prediction=final_prediction,
            probabilities=final_probabilities,
            explanation=explanation_obj
        )
        
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Terjadi kesalahan saat prediksi: {e}")

# --- ENDPOINT 2: REKOMENDASI MATA KULIAH ---
@app.post("/recommend/", response_model=List[CourseRecommendation])
async def recommend_courses(request: RecommendationRequest):
    if not course_details_map:
        raise HTTPException(status_code=503, detail="Data kurikulum belum siap. Silakan coba lagi nanti.")

    ranked_candidates = get_recommendations_logic(
        request.current_semester, 
        request.courses_passed,
        request.mk_pilihan_failed
    )
    
    top_3_candidates = ranked_candidates[:3]
    
    response_output = []
    for i, course in enumerate(top_3_candidates):
        rank = i + 1
        
        is_tertinggal_status = False
        reason = "Rekomendasi semester ini"
        
        if course.get("is_retake_elective"):
            reason = "Wajib Mengulang (MK Pilihan Gagal)"
            is_tertinggal_status = True
        elif course["semester_plan"] < request.current_semester:
            reason = f"Mata kuliah tertinggal (Semester {course['semester_plan']})"
            is_tertinggal_status = True
        elif course["semester_plan"] > request.current_semester:
            reason = f"Akselerasi (Semester {course['semester_plan']})"

        prereq_codes = prereq_map.get(course["code"], [])
        prereq_details_list = []
        for p_code in prereq_codes:
            if p_code in course_details_map:
                prereq_details_list.append(
                    PrerequisiteInfo(code=p_code, name=course_details_map[p_code]["name"])
                )

        response_output.append(
            CourseRecommendation(
                rank=rank,
                code=course["code"],
                name=course["name"],
                sks=course["sks"],
                semester_plan=course["semester_plan"],
                reason=reason,
                is_tertinggal=is_tertinggal_status,
                priority_score=course["priority_score"],
                prerequisites=prereq_details_list
            )
        )
        
    return response_output

# --- ENDPOINT 3: PREDIKSI KELULUSAN TEPAT WAKTU (LTW) ---
@app.post("/predict-graduation/", response_model=GraduationCheckResponse)
def check_graduation_status(request: GraduationCheckRequest):
    """
    Endpoint untuk mengecek apakah mahasiswa masih on-track lulus di Semester 8
    berdasarkan sisa SKS, kapasitas IPK, dan rantai prasyarat (Graf).
    """
    result = predict_graduation_status(
        current_semester=request.current_semester,
        total_sks_passed=request.total_sks_passed,
        last_gpa=request.ipk_last_semester,
        graph_G=G,                      # Pass Graf Global (Reference)
        passed_courses=request.courses_passed # Pass data matkul user
    )
    
    return GraduationCheckResponse(**result)