import json
import os
from datetime import datetime

DATA_FILE = "data.json"

def _load() -> dict:
    """Load data.json, create if missing."""
    if not os.path.exists(DATA_FILE):
        default = {
            "resume": {"raw_text": "", "last_updated": ""},
            "applications": [],
            "job_cache": [],
            "settings": {
                "preferred_roles": [],
                "preferred_keywords": [],
                "groq_model": "llama-3.1-8b-instant"
            },
            "chat_history": []
        }
        _save(default)
        return default
    with open(DATA_FILE, "r", encoding="utf-8") as f:
        return json.load(f)

def _save(data: dict):
    """Write dict back to data.json."""
    with open(DATA_FILE, "w", encoding="utf-8") as f:
        json.dump(data, f, indent=2, ensure_ascii=False)

# ── Resume ────────────────────────────────────────────
def save_resume(text: str):
    data = _load()
    data["resume"]["raw_text"] = text.strip()
    data["resume"]["last_updated"] = datetime.now().isoformat()
    _save(data)

def load_resume() -> str:
    return _load()["resume"]["raw_text"]

def resume_last_updated() -> str:
    return _load()["resume"].get("last_updated", "")

# ── Applications ──────────────────────────────────────
def save_application(app: dict):
    data = _load()
    # Avoid duplicate by job_id
    existing_ids = [a["job_id"] for a in data["applications"]]
    if app["job_id"] not in existing_ids:
        data["applications"].append(app)
        _save(data)
        return True
    return False  # Already applied

def load_applications() -> list:
    return _load()["applications"]

def update_application_status(job_id: str, new_status: str):
    data = _load()
    for app in data["applications"]:
        if app["job_id"] == job_id:
            app["status"] = new_status
            break
    _save(data)

def delete_application(job_id: str):
    data = _load()
    data["applications"] = [
        a for a in data["applications"] if a["job_id"] != job_id
    ]
    _save(data)

# ── Job Cache ─────────────────────────────────────────
def save_job_cache(jobs: list):
    data = _load()
    data["job_cache"] = jobs
    _save(data)

def load_job_cache() -> list:
    return _load()["job_cache"]

# ── Settings ──────────────────────────────────────────
def load_settings() -> dict:
    return _load()["settings"]

def save_settings(settings: dict):
    data = _load()
    data["settings"].update(settings)
    _save(data)

# ── Chat History ──────────────────────────────────────
def save_chat_message(role: str, content: str):
    data = _load()
    data["chat_history"].append({
        "role": role,
        "content": content,
        "timestamp": datetime.now().isoformat()
    })
    # Keep last 50 messages only
    data["chat_history"] = data["chat_history"][-50:]
    _save(data)

def load_chat_history() -> list:
    return _load()["chat_history"]

def clear_chat_history():
    data = _load()
    data["chat_history"] = []
    _save(data)

# ── Stats ─────────────────────────────────────────────
def get_stats() -> dict:
    apps = load_applications()
    return {
        "total": len(apps),
        "applied": len([a for a in apps if a["status"] == "Applied"]),
        "pending": len([a for a in apps if a["status"] == "Pending"]),
        "skipped": len([a for a in apps if a["status"] == "Skipped"]),
    }