"""
SQLite database setup and CRUD operations for leads and message templates.
"""

import sqlite3
import csv
import io
import os
from datetime import datetime
from typing import Optional

DB_PATH = os.path.join(os.path.dirname(__file__), "leads.db")


def get_connection():
    """Get a database connection with row factory."""
    conn = sqlite3.connect(DB_PATH)
    conn.row_factory = sqlite3.Row
    return conn


def init_db():
    """Initialize the database tables and seed default template."""
    conn = get_connection()
    cursor = conn.cursor()

    cursor.execute("""
        CREATE TABLE IF NOT EXISTS leads (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            name TEXT NOT NULL,
            phone TEXT,
            address TEXT,
            website TEXT,
            email TEXT,
            instagram TEXT,
            linkedin TEXT,
            status TEXT DEFAULT 'new',
            notes TEXT DEFAULT '',
            follow_up_date TEXT,
            created_at TEXT DEFAULT (datetime('now'))
        )
    """)

    # Gracefully add new columns to an existing database
    try: cursor.execute("ALTER TABLE leads ADD COLUMN email TEXT")
    except sqlite3.OperationalError: pass
    
    try: cursor.execute("ALTER TABLE leads ADD COLUMN instagram TEXT")
    except sqlite3.OperationalError: pass
    
    try: cursor.execute("ALTER TABLE leads ADD COLUMN linkedin TEXT")
    except sqlite3.OperationalError: pass

    cursor.execute("""
        CREATE TABLE IF NOT EXISTS templates (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            name TEXT NOT NULL,
            content TEXT NOT NULL,
            created_at TEXT DEFAULT (datetime('now'))
        )
    """)

    # Seed a default template if none exist
    cursor.execute("SELECT COUNT(*) FROM templates")
    if cursor.fetchone()[0] == 0:
        cursor.execute(
            "INSERT INTO templates (name, content) VALUES (?, ?)",
            (
                "Default Outreach",
                "Hi, I saw your business online and noticed you don't have a proper website. "
                "I help businesses get more customers by building simple, fast websites. "
                "Would you like to see a demo?",
            ),
        )

    conn.commit()
    conn.close()


# ──────────────────────────── Lead CRUD ────────────────────────────


def insert_lead(name: str, phone: str = None, address: str = None, website: str = None, email: str = None, instagram: str = None, linkedin: str = None):
    """Insert a new lead into the database."""
    conn = get_connection()
    cursor = conn.cursor()
    cursor.execute(
        "INSERT INTO leads (name, phone, address, website, email, instagram, linkedin) VALUES (?, ?, ?, ?, ?, ?, ?)",
        (name, phone, address, website, email, instagram, linkedin),
    )
    conn.commit()
    lead_id = cursor.lastrowid
    conn.close()
    return lead_id


def get_all_leads(
    search: Optional[str] = None,
    status: Optional[str] = None,
    sort_by: str = "created_at",
    sort_order: str = "desc",
):
    """Get all leads with optional search and filter."""
    conn = get_connection()
    cursor = conn.cursor()

    query = "SELECT * FROM leads WHERE 1=1"
    params = []

    if search:
        query += " AND (name LIKE ? OR phone LIKE ? OR address LIKE ?)"
        like = f"%{search}%"
        params.extend([like, like, like])

    if status:
        query += " AND status = ?"
        params.append(status)

    # Whitelist sort columns to prevent SQL injection
    allowed_sort = {"created_at", "name", "status", "follow_up_date"}
    if sort_by not in allowed_sort:
        sort_by = "created_at"
    order = "DESC" if sort_order.lower() == "desc" else "ASC"
    query += f" ORDER BY {sort_by} {order}"

    cursor.execute(query, params)
    rows = cursor.fetchall()
    conn.close()
    return [dict(row) for row in rows]


def get_lead_by_id(lead_id: int):
    """Get a single lead by ID."""
    conn = get_connection()
    cursor = conn.cursor()
    cursor.execute("SELECT * FROM leads WHERE id = ?", (lead_id,))
    row = cursor.fetchone()
    conn.close()
    return dict(row) if row else None


def update_lead(lead_id: int, **kwargs):
    """Update a lead's fields."""
    conn = get_connection()
    cursor = conn.cursor()

    # Filter out None values
    updates = {k: v for k, v in kwargs.items() if v is not None}
    if not updates:
        conn.close()
        return False

    set_clause = ", ".join(f"{k} = ?" for k in updates)
    values = list(updates.values()) + [lead_id]

    cursor.execute(f"UPDATE leads SET {set_clause} WHERE id = ?", values)
    conn.commit()
    affected = cursor.rowcount
    conn.close()
    return affected > 0


def delete_lead(lead_id: int):
    """Delete a lead by ID."""
    conn = get_connection()
    cursor = conn.cursor()
    cursor.execute("DELETE FROM leads WHERE id = ?", (lead_id,))
    conn.commit()
    affected = cursor.rowcount
    conn.close()
    return affected > 0


# ──────────────────────────── Stats ────────────────────────────


def get_dashboard_stats():
    """Get aggregated stats for the dashboard."""
    conn = get_connection()
    cursor = conn.cursor()
    cursor.execute("""
        SELECT
            COUNT(*) as total,
            COALESCE(SUM(CASE WHEN status = 'new' THEN 1 ELSE 0 END), 0) as new,
            COALESCE(SUM(CASE WHEN status = 'contacted' THEN 1 ELSE 0 END), 0) as contacted,
            COALESCE(SUM(CASE WHEN status = 'replied' THEN 1 ELSE 0 END), 0) as replied,
            COALESCE(SUM(CASE WHEN status = 'closed' THEN 1 ELSE 0 END), 0) as closed
        FROM leads
    """)
    row = cursor.fetchone()
    conn.close()
    # Ensure all values are integers (not None)
    result = dict(row)
    return {k: (v or 0) for k, v in result.items()}


# ──────────────────────────── CSV Export ────────────────────────────


def export_leads_csv(status: Optional[str] = None):
    """Export leads to CSV string."""
    leads = get_all_leads(status=status)
    output = io.StringIO()
    writer = csv.DictWriter(
        output,
        fieldnames=["id", "name", "phone", "address", "website", "email", "instagram", "linkedin", "status", "notes", "follow_up_date", "created_at"],
    )
    writer.writeheader()
    writer.writerows(leads)
    return output.getvalue()


# ──────────────────────────── Template CRUD ────────────────────────────


def get_all_templates():
    """Get all message templates."""
    conn = get_connection()
    cursor = conn.cursor()
    cursor.execute("SELECT * FROM templates ORDER BY created_at DESC")
    rows = cursor.fetchall()
    conn.close()
    return [dict(row) for row in rows]


def create_template(name: str, content: str):
    """Create a new message template."""
    conn = get_connection()
    cursor = conn.cursor()
    cursor.execute(
        "INSERT INTO templates (name, content) VALUES (?, ?)",
        (name, content),
    )
    conn.commit()
    tid = cursor.lastrowid
    conn.close()
    return tid


def update_template(template_id: int, **kwargs):
    """Update a template."""
    conn = get_connection()
    cursor = conn.cursor()
    updates = {k: v for k, v in kwargs.items() if v is not None}
    if not updates:
        conn.close()
        return False
    set_clause = ", ".join(f"{k} = ?" for k in updates)
    values = list(updates.values()) + [template_id]
    cursor.execute(f"UPDATE templates SET {set_clause} WHERE id = ?", values)
    conn.commit()
    affected = cursor.rowcount
    conn.close()
    return affected > 0


def delete_template(template_id: int):
    """Delete a template."""
    conn = get_connection()
    cursor = conn.cursor()
    cursor.execute("DELETE FROM templates WHERE id = ?", (template_id,))
    conn.commit()
    affected = cursor.rowcount
    conn.close()
    return affected > 0