"""
models.py
=========
SQLite database layer for the Theme Song Booth.

This module defines the schema and all database operations. Flask's
application context (`g`) is used to manage one connection per request.

Schema overview (see SCHEMA constant):
- requests table stores customer data, generated prompts, file paths,
  approval state, email timestamps, payment reference, player token,
  vocal gender preference, revision count, revision note, and operator notes.
- Revisions: when a customer requests changes, the current A/B MP3 files are
  renamed to archived "RevN-" copies and new versions are uploaded later.
- operator_notes is an internal column for the booth team and is never shown
  to customers.
- Indexes on status and player_token for fast queue/lookup.
"""

import sqlite3
import secrets
from datetime import datetime, timezone
from pathlib import Path
from flask import current_app, g

# SQL executed by init_db() to create the requests table and indexes.
SCHEMA = """
CREATE TABLE IF NOT EXISTS requests (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    name TEXT NOT NULL,
    email TEXT NOT NULL,
    hobbies TEXT,
    notable_facts TEXT,
    style_genre TEXT,
    pronouns TEXT,
    extra_requests TEXT,
    status TEXT DEFAULT 'pending',
    suno_title TEXT,
    suno_style TEXT,
    suno_lyrics TEXT,
    song_a_path TEXT,
    song_b_path TEXT,
    vocal_gender TEXT,
    customer_approved TEXT DEFAULT 'none',
    approval_notified_at TIMESTAMP,
    preview_sent_at TIMESTAMP,
    delivery_sent_at TIMESTAMP,
    square_payment_ref TEXT,
    admin_alert_email TEXT,  -- reserved for future operator alerts; currently unused
    player_token TEXT NOT NULL UNIQUE,
    revision_count INTEGER DEFAULT 0,
    revision_note TEXT,
    operator_notes TEXT,
    stems_link TEXT
);

CREATE INDEX IF NOT EXISTS idx_requests_status ON requests(status);
CREATE INDEX IF NOT EXISTS idx_requests_token ON requests(player_token);

CREATE TABLE IF NOT EXISTS revision_history (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    request_id INTEGER NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    revision_count INTEGER NOT NULL,
    note TEXT,
    old_song_a_path TEXT,
    old_song_b_path TEXT,
    new_song_a_path TEXT,
    new_song_b_path TEXT,
    FOREIGN KEY (request_id) REFERENCES requests(id) ON DELETE CASCADE
);

CREATE INDEX IF NOT EXISTS idx_revision_history_request ON revision_history(request_id);
"""


def get_db():
    """Get or create a SQLite connection tied to the current Flask request context."""
    if 'db' not in g:
        g.db = sqlite3.connect(current_app.config['DATABASE'])
        g.db.row_factory = sqlite3.Row
    return g.db


def close_db(e=None):
    """Close the request-scoped SQLite connection. Registered as teardown handler."""
    db = g.pop('db', None)
    if db is not None:
        db.close()


def init_db():
    """Create the database file and tables, adding any missing columns to existing tables."""
    db_path = current_app.config['DATABASE']
    Path(db_path).parent.mkdir(parents=True, exist_ok=True)
    db = sqlite3.connect(db_path)
    db.row_factory = sqlite3.Row
    db.executescript(SCHEMA)

    # SQLite ALTER TABLE is limited; add newer columns if they are missing.
    expected_columns = {
        'requests': [
            'id', 'created_at', 'name', 'email', 'hobbies', 'notable_facts',
            'style_genre', 'pronouns', 'extra_requests', 'status', 'suno_title', 'suno_style',
            'suno_lyrics', 'song_a_path', 'song_b_path', 'vocal_gender',
            'customer_approved', 'approval_notified_at', 'preview_sent_at',
            'delivery_sent_at', 'square_payment_ref', 'admin_alert_email',
            'player_token', 'revision_count', 'revision_note', 'operator_notes',
            'stems_link'
        ],
        'revision_history': [
            'id', 'created_at', 'request_id', 'revision_count', 'note',
            'old_song_a_path', 'old_song_b_path', 'new_song_a_path', 'new_song_b_path'
        ]
    }
    for table, columns in expected_columns.items():
        existing = {r['name'] for r in db.execute(f"PRAGMA table_info({table})")}
        for col in columns:
            if col not in existing:
                # revision_count must be INTEGER so arithmetic in app.py works.
                col_type = 'INTEGER' if col == 'revision_count' else 'TEXT'
                db.execute(f'ALTER TABLE {table} ADD COLUMN {col} {col_type}')
    db.commit()
    db.close()


def new_token():
    """Generate a URL-safe random token used for private player links."""
    return secrets.token_urlsafe(32)


def now_utc():
    """Return current UTC time as ISO-8601 string for timestamp columns."""
    return datetime.now(timezone.utc).isoformat()


def create_request(name, email, hobbies, notable_facts, style_genre, extra_requests, vocal_gender=None, pronouns=None):
    """
    Insert a new customer request.
    Returns the auto-generated request id.
    """
    db = get_db()
    cur = db.execute(
        """INSERT INTO requests
           (name, email, hobbies, notable_facts, style_genre, pronouns, extra_requests, vocal_gender, player_token)
           VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)""",
        (name, email, hobbies, notable_facts, style_genre, pronouns, extra_requests, vocal_gender, new_token())
    )
    db.commit()
    return cur.lastrowid


def get_request_by_id(request_id):
    """Fetch one request by numeric id. Returns dict or None."""
    db = get_db()
    row = db.execute('SELECT * FROM requests WHERE id = ?', (request_id,)).fetchone()
    return dict(row) if row else None


def get_request_by_token(token):
    """Fetch one request by its private player token. Returns dict or None."""
    db = get_db()
    row = db.execute('SELECT * FROM requests WHERE player_token = ?', (token,)).fetchone()
    return dict(row) if row else None


def list_requests(status=None):
    """List all requests, optionally filtered by status, newest first.
    Normalizes whitespace in the status parameter so URLs like "Needs Upload"
    match the stored value."""
    db = get_db()
    if status:
        # Translate human filter names to stored status values.
        status = status.lower().replace(' ', '_')
        rows = db.execute('SELECT * FROM requests WHERE status = ? ORDER BY created_at DESC', (status,)).fetchall()
    else:
        rows = db.execute('SELECT * FROM requests ORDER BY created_at DESC').fetchall()
    return [dict(r) for r in rows]


def get_requests_by_email(email):
    """Fetch all requests for a given email address, newest first.
    Email is compared case-insensitively and stripped of whitespace."""
    db = get_db()
    rows = db.execute(
        "SELECT * FROM requests WHERE LOWER(TRIM(email)) = LOWER(TRIM(?)) ORDER BY created_at DESC",
        (email,)
    ).fetchall()
    return [dict(r) for r in rows]


def update_request(request_id, **fields):
    """
    Update arbitrary columns for a request.
    Example: update_request(1, status='prompt_ready', suno_style='...')
    """
    if not fields:
        return
    db = get_db()
    cols = ', '.join(f'{k} = ?' for k in fields)
    vals = list(fields.values()) + [request_id]
    db.execute(f'UPDATE requests SET {cols} WHERE id = ?', vals)
    db.commit()


def delete_request(request_id):
    """Delete a single request row by id. Does NOT delete associated files
    (the caller in app.py removes uploads before/after this call)."""
    db = get_db()
    db.execute('DELETE FROM requests WHERE id = ?', (request_id,))
    db.commit()


def log_revision(request_id, revision_count, note, old_a=None, old_b=None, new_a=None, new_b=None):
    """Record a revision event in the revision_history table, creating it if it is missing."""
    db = get_db()
    try:
        db.execute(
            """INSERT INTO revision_history
               (request_id, revision_count, note, old_song_a_path, old_song_b_path, new_song_a_path, new_song_b_path)
               VALUES (?, ?, ?, ?, ?, ?, ?)""",
            (request_id, revision_count, note, old_a, old_b, new_a, new_b)
        )
        db.commit()
    except sqlite3.OperationalError as e:
        if 'no such table' in str(e):
            # Schema drift: table missing. Run init_db to add tables/columns, then retry once.
            init_db()
            db.execute(
                """INSERT INTO revision_history
                   (request_id, revision_count, note, old_song_a_path, old_song_b_path, new_song_a_path, new_song_b_path)
                   VALUES (?, ?, ?, ?, ?, ?, ?)""",
                (request_id, revision_count, note, old_a, old_b, new_a, new_b)
            )
            db.commit()
        else:
            raise


def list_revision_history(request_id):
    """Return all revision history rows for a request, oldest first."""
    db = get_db()
    rows = db.execute(
        'SELECT * FROM revision_history WHERE request_id = ? ORDER BY created_at ASC',
        (request_id,)
    ).fetchall()
    return [dict(r) for r in rows]


def reset_all_requests():
    """Delete every row in the requests table and reset id auto-increment."""
    db = get_db()
    db.execute('DELETE FROM requests')
    db.execute('DELETE FROM sqlite_sequence WHERE name = ?', ('requests',))
    db.commit()