"""
Data Loader for Kalim Chatbot
Utilities for loading and accessing the processed knowledge base
"""
import json
from typing import Dict, List, Optional, Any
from functools import lru_cache

from config.settings import (
    MAJORS_JSON_FILE,
    LOCATIONS_JSON_FILE,
    HOLLAND_MAPPING_FILE,
    HOLLAND_CODES,
    SECONDARY_TRACKS,
    GOVERNORATES
)


@lru_cache(maxsize=1)
def load_majors() -> List[Dict[str, Any]]:
    """Load majors data from JSON file."""
    if not MAJORS_JSON_FILE.exists():
        raise FileNotFoundError(
            f"Majors file not found: {MAJORS_JSON_FILE}\n"
            "Run 'python -m src.data.processor' first to generate the data."
        )

    with open(MAJORS_JSON_FILE, 'r', encoding='utf-8') as f:
        data = json.load(f)

    return data.get('majors', [])

@lru_cache(maxsize=1)
def load_holland_mapping() -> Dict[str, Any]:
    """Load Holland RIASEC mapping from JSON file."""
    if not HOLLAND_MAPPING_FILE.exists():
        # Return default if file doesn't exist
        return {
            "codes": HOLLAND_CODES,
            "code_list": ["R", "I", "A", "S", "E", "C"],
            "dropdown_options": [
                {"code": "R", "label": "R - الواقعي (Realistic)"},
                {"code": "I", "label": "I - الباحث (Investigative)"},
                {"code": "A", "label": "A - الفني (Artistic)"},
                {"code": "S", "label": "S - الاجتماعي (Social)"},
                {"code": "E", "label": "E - المغامر (Enterprising)"},
                {"code": "C", "label": "C - التقليدي (Conventional)"},
            ]
        }

    with open(HOLLAND_MAPPING_FILE, 'r', encoding='utf-8') as f:
        return json.load(f)


def get_major_by_id(major_id: int) -> Optional[Dict[str, Any]]:
    """Get a specific major by ID."""
    majors = load_majors()
    for major in majors:
        if major['id'] == major_id:
            return major
    return None

def get_governorates() -> List[str]:
    """Get list of all governorates."""
    return list(GOVERNORATES.keys())


def get_districts(governorate: str) -> List[str]:
    """Get districts for a specific governorate."""
    return GOVERNORATES.get(governorate, [])


@lru_cache(maxsize=1)
def get_dataset_governorates() -> List[str]:
    """Governorates that actually occur in majors.json, in GOVERNORATES order.

    The UI must offer only these. `GOVERNORATES` follows Lebanon's newer
    eight-governorate division, in which عكار and بعلبك-الهرمل are governorates
    of their own; the dataset follows the older six, filing حلبا under
    الشمال/عكار and دورس under البقاع/بعلبك. Offering the config's list let a
    student from Akkar finish the whole wizard and be told no major matched —
    a dead end that reads as "the university has nothing for you" when the
    branch exists one level down.
    """
    present = {
        loc.get('governorate')
        for major in load_majors()
        for loc in major.get('locations', [])
        if loc.get('governorate')
    }
    return [g for g in GOVERNORATES if g != "الكل" and g in present]


@lru_cache(maxsize=1)
def _dataset_districts_by_gov() -> Dict[str, List[str]]:
    by_gov: Dict[str, set] = {}
    for major in load_majors():
        for loc in major.get('locations', []):
            gov, district = loc.get('governorate'), loc.get('district')
            if gov and district:
                by_gov.setdefault(gov, set()).add(district)
    return {gov: sorted(names) for gov, names in by_gov.items()}


def get_dataset_districts(governorate: str) -> List[str]:
    """Districts of this governorate present in majors.json.

    Kept in the GOVERNORATES reference order where possible, with anything the
    config map does not list appended — that is how عكار (a district of الشمال
    in the data, a governorate in the config) still reaches the dropdown.
    """
    present = set(_dataset_districts_by_gov().get(governorate, []))
    ordered = [d for d in GOVERNORATES.get(governorate, []) if d in present]
    return ordered + sorted(present - set(ordered))

# Export commonly used functions
__all__ = [
    'load_majors',
    'load_holland_mapping',
    'get_major_by_id',
    'get_governorates',
    'get_districts',
    'get_dataset_governorates',
    'get_dataset_districts',
]