"""
SQLite database setup using Python's built-in sqlite3.
Database file: backend/evolve.db
No extra packages needed — sqlite3 is part of Python stdlib.
"""
import sqlite3
import os
import json
from datetime import datetime
from pathlib import Path

# DB path: use DB_PATH env var if set (Hugging Face /data/), else local
import os
_env_path = os.environ.get("DB_PATH")
DB_PATH = Path(_env_path) if _env_path else Path(__file__).parent.parent / "evolve.db"


def get_conn() -> sqlite3.Connection:
    """Return a new SQLite connection with row_factory for dict-like access."""
    conn = sqlite3.connect(str(DB_PATH))
    conn.row_factory = sqlite3.Row          # rows behave like dicts
    conn.execute("PRAGMA journal_mode=WAL") # better concurrent read performance
    conn.execute("PRAGMA foreign_keys=ON")
    return conn


def init_db():
    """Create all tables if they don't exist. Called once on startup."""
    conn = get_conn()
    cur = conn.cursor()

    # ── Uploaded data tables ────────────────────────────────────────
    cur.execute("""
        CREATE TABLE IF NOT EXISTS bms_data (
            id          INTEGER PRIMARY KEY AUTOINCREMENT,
            vehicle_id  TEXT    NOT NULL,
            timestamp   TEXT    NOT NULL,
            soc         REAL,
            voltage     REAL,
            current     REAL,
            temperature REAL,
            cycle_count INTEGER,
            odometer_km REAL,
            uploaded_at TEXT    NOT NULL DEFAULT (datetime('now'))
        )
    """)

    cur.execute("""
        CREATE TABLE IF NOT EXISTS fleet_data (
            id                  INTEGER PRIMARY KEY AUTOINCREMENT,
            asset_id            TEXT    NOT NULL UNIQUE,
            category            TEXT,
            route_distance_km   REAL,
            payload_tons        REAL,
            duty_cycle_hrs      REAL,
            dwell_time_hrs      REAL,
            terrain_score       REAL,
            diesel_l_per_100km  REAL,
            age_years           REAL,
            uploaded_at         TEXT    NOT NULL DEFAULT (datetime('now'))
        )
    """)

    cur.execute("""
        CREATE TABLE IF NOT EXISTS supplier_data (
            id                  INTEGER PRIMARY KEY AUTOINCREMENT,
            supplier_id         TEXT    NOT NULL UNIQUE,
            name                TEXT,
            tier                INTEGER,
            material            TEXT,
            country             TEXT,
            geopolitical_risk   REAL,
            esg_score           REAL,
            quality_score       REAL,
            lead_time_days      INTEGER,
            concentration_pct   REAL,
            uploaded_at         TEXT    NOT NULL DEFAULT (datetime('now'))
        )
    """)

    cur.execute("""
        CREATE TABLE IF NOT EXISTS inspection_data (
            id              INTEGER PRIMARY KEY AUTOINCREMENT,
            lot_id          TEXT    NOT NULL,
            supplier_id     TEXT    NOT NULL,
            material        TEXT,
            defect_rate     REAL,
            inspection_date TEXT,
            root_cause_hint TEXT,
            uploaded_at     TEXT    NOT NULL DEFAULT (datetime('now'))
        )
    """)

    # ── Activity / audit log ────────────────────────────────────────
    cur.execute("""
        CREATE TABLE IF NOT EXISTS activity_log (
            id          INTEGER PRIMARY KEY AUTOINCREMENT,
            timestamp   TEXT    NOT NULL DEFAULT (datetime('now')),
            user        TEXT    NOT NULL DEFAULT 'Admin',
            action      TEXT    NOT NULL,
            endpoint    TEXT,
            method      TEXT,
            status_code INTEGER,
            details     TEXT    -- JSON string for extra metadata
        )
    """)

    # ── Upload history ──────────────────────────────────────────────
    cur.execute("""
        CREATE TABLE IF NOT EXISTS upload_history (
            id          INTEGER PRIMARY KEY AUTOINCREMENT,
            timestamp   TEXT    NOT NULL DEFAULT (datetime('now')),
            user        TEXT    NOT NULL DEFAULT 'Admin',
            data_type   TEXT    NOT NULL,   -- bms / fleet / suppliers / inspections
            filename    TEXT,
            row_count   INTEGER,
            status      TEXT    NOT NULL DEFAULT 'success',
            error_msg   TEXT
        )
    """)

    conn.commit()
    conn.close()
    print(f"[DB] SQLite database ready at: {DB_PATH}")


# ── Helpers ─────────────────────────────────────────────────────────

def log_activity(action: str, endpoint: str = None, method: str = None,
                 status_code: int = 200, details: dict = None, user: str = "Admin"):
    """Insert one row into activity_log."""
    conn = get_conn()
    conn.execute(
        """INSERT INTO activity_log (timestamp, user, action, endpoint, method, status_code, details)
           VALUES (datetime('now'), ?, ?, ?, ?, ?, ?)""",
        (user, action, endpoint, method, status_code, json.dumps(details) if details else None)
    )
    conn.commit()
    conn.close()


def log_upload(data_type: str, filename: str, row_count: int,
               status: str = "success", error_msg: str = None, user: str = "Admin"):
    """Insert one row into upload_history."""
    conn = get_conn()
    conn.execute(
        """INSERT INTO upload_history (timestamp, user, data_type, filename, row_count, status, error_msg)
           VALUES (datetime('now'), ?, ?, ?, ?, ?, ?)""",
        (user, data_type, filename, row_count, status, error_msg)
    )
    conn.commit()
    conn.close()


def get_activity_log(limit: int = 100) -> list:
    conn = get_conn()
    rows = conn.execute(
        "SELECT * FROM activity_log ORDER BY timestamp DESC LIMIT ?", (limit,)
    ).fetchall()
    conn.close()
    return [dict(r) for r in rows]


def get_upload_history(limit: int = 50) -> list:
    conn = get_conn()
    rows = conn.execute(
        "SELECT * FROM upload_history ORDER BY timestamp DESC LIMIT ?", (limit,)
    ).fetchall()
    conn.close()
    return [dict(r) for r in rows]