"""Acesso ao SQLite: esquema, migrações leves e helpers de consulta.

Estende o esquema original (uploaded_files -> detected_documents -> fiscal_documents)
com autenticação (users), lotes de importação (import_batches) e os campos de
legibilidade usados pela extração por IA.
"""

from __future__ import annotations

import json
import sqlite3
from contextlib import contextmanager
from pathlib import Path
from typing import Any, Iterator

from .config import get_settings


SCHEMA = """
CREATE TABLE IF NOT EXISTS users (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    username TEXT NOT NULL UNIQUE,
    password_hash TEXT NOT NULL,
    created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS import_batches (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    status TEXT NOT NULL DEFAULT 'open',
    created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
    confirmed_at TEXT
);

CREATE TABLE IF NOT EXISTS uploaded_files (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    batch_id INTEGER REFERENCES import_batches(id) ON DELETE SET NULL,
    original_name TEXT NOT NULL,
    stored_path TEXT NOT NULL,
    content_type TEXT NOT NULL,
    size_bytes INTEGER NOT NULL,
    status TEXT NOT NULL DEFAULT 'pending',
    detected_count INTEGER NOT NULL DEFAULT 0,
    message TEXT,
    created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
    updated_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS detected_documents (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    upload_id INTEGER NOT NULL REFERENCES uploaded_files(id) ON DELETE CASCADE,
    batch_id INTEGER REFERENCES import_batches(id) ON DELETE SET NULL,
    source_file_name TEXT NOT NULL,
    source_page INTEGER,
    source_location TEXT NOT NULL,
    raw_text TEXT NOT NULL DEFAULT '',
    purchase_date TEXT,
    supplier_name TEXT,
    total_paid REAL,
    confidence TEXT NOT NULL DEFAULT 'low',
    field_confidence_json TEXT NOT NULL DEFAULT '{}',
    legible INTEGER NOT NULL DEFAULT 1,
    uncertain_fields TEXT NOT NULL DEFAULT '[]',
    extractor TEXT NOT NULL DEFAULT 'local',
    status TEXT NOT NULL DEFAULT 'staged',
    created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
    updated_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE TABLE IF NOT EXISTS fiscal_documents (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    detected_document_id INTEGER REFERENCES detected_documents(id) ON DELETE SET NULL,
    source_file_name TEXT NOT NULL DEFAULT '',
    source_location TEXT NOT NULL DEFAULT '',
    purchase_date TEXT NOT NULL,
    supplier_name TEXT NOT NULL,
    total_paid REAL NOT NULL,
    confidence TEXT NOT NULL DEFAULT 'high',
    created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
    updated_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP
);

CREATE INDEX IF NOT EXISTS idx_fiscal_date ON fiscal_documents(purchase_date);
CREATE INDEX IF NOT EXISTS idx_detected_batch ON detected_documents(batch_id, status);
"""


def connect(db_path: Path | None = None) -> sqlite3.Connection:
    settings = get_settings()
    settings.ensure_storage()
    conn = sqlite3.connect(db_path or settings.db_path)
    conn.row_factory = sqlite3.Row
    conn.execute("PRAGMA foreign_keys = ON")
    conn.execute("PRAGMA journal_mode = WAL")
    return conn


def init_db(conn: sqlite3.Connection) -> None:
    conn.executescript(SCHEMA)
    conn.commit()


@contextmanager
def session(db_path: Path | None = None) -> Iterator[sqlite3.Connection]:
    conn = connect(db_path)
    try:
        init_db(conn)
        yield conn
    finally:
        conn.close()


# --------------------------------------------------------------------------- #
# Usuários
# --------------------------------------------------------------------------- #
def count_users(conn: sqlite3.Connection) -> int:
    return int(conn.execute("SELECT COUNT(*) FROM users").fetchone()[0])


def get_user(conn: sqlite3.Connection, username: str) -> sqlite3.Row | None:
    return conn.execute(
        "SELECT * FROM users WHERE username = ?", (username,)
    ).fetchone()


def create_user(conn: sqlite3.Connection, username: str, password_hash: str) -> int:
    cur = conn.execute(
        "INSERT INTO users (username, password_hash) VALUES (?, ?)",
        (username, password_hash),
    )
    conn.commit()
    return int(cur.lastrowid)


def update_password(conn: sqlite3.Connection, username: str, password_hash: str) -> None:
    conn.execute(
        "UPDATE users SET password_hash = ? WHERE username = ?",
        (password_hash, username),
    )
    conn.commit()


# --------------------------------------------------------------------------- #
# Lotes de importação
# --------------------------------------------------------------------------- #
def create_batch(conn: sqlite3.Connection) -> int:
    cur = conn.execute("INSERT INTO import_batches (status) VALUES ('open')")
    conn.commit()
    return int(cur.lastrowid)


def get_batch(conn: sqlite3.Connection, batch_id: int) -> sqlite3.Row | None:
    return conn.execute(
        "SELECT * FROM import_batches WHERE id = ?", (batch_id,)
    ).fetchone()


def set_batch_status(conn: sqlite3.Connection, batch_id: int, status: str) -> None:
    if status == "confirmed":
        conn.execute(
            "UPDATE import_batches SET status = ?, confirmed_at = CURRENT_TIMESTAMP WHERE id = ?",
            (status, batch_id),
        )
    else:
        conn.execute(
            "UPDATE import_batches SET status = ? WHERE id = ?", (status, batch_id)
        )
    conn.commit()


# --------------------------------------------------------------------------- #
# Uploads
# --------------------------------------------------------------------------- #
def insert_upload(
    conn: sqlite3.Connection,
    batch_id: int,
    original_name: str,
    stored_path: Path,
    content_type: str,
    size_bytes: int,
) -> int:
    cur = conn.execute(
        """
        INSERT INTO uploaded_files (batch_id, original_name, stored_path, content_type, size_bytes)
        VALUES (?, ?, ?, ?, ?)
        """,
        (batch_id, original_name, str(stored_path), content_type, size_bytes),
    )
    conn.commit()
    return int(cur.lastrowid)


def update_upload_status(
    conn: sqlite3.Connection,
    upload_id: int,
    status: str,
    detected_count: int,
    message: str | None = None,
) -> None:
    conn.execute(
        """
        UPDATE uploaded_files
           SET status = ?, detected_count = ?, message = ?, updated_at = CURRENT_TIMESTAMP
         WHERE id = ?
        """,
        (status, detected_count, message, upload_id),
    )
    conn.commit()


def get_upload(conn: sqlite3.Connection, upload_id: int) -> sqlite3.Row | None:
    return conn.execute(
        "SELECT * FROM uploaded_files WHERE id = ?", (upload_id,)
    ).fetchone()


# --------------------------------------------------------------------------- #
# Documentos detectados (staging)
# --------------------------------------------------------------------------- #
def insert_detected(
    conn: sqlite3.Connection,
    *,
    upload_id: int,
    batch_id: int,
    source_file_name: str,
    source_page: int | None,
    source_location: str,
    raw_text: str,
    purchase_date: str | None,
    supplier_name: str | None,
    total_paid: float | None,
    confidence: str,
    field_confidence: dict[str, str],
    legible: bool,
    uncertain_fields: list[str],
    extractor: str,
) -> int:
    cur = conn.execute(
        """
        INSERT INTO detected_documents (
            upload_id, batch_id, source_file_name, source_page, source_location,
            raw_text, purchase_date, supplier_name, total_paid, confidence,
            field_confidence_json, legible, uncertain_fields, extractor, status
        ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, 'staged')
        """,
        (
            upload_id,
            batch_id,
            source_file_name,
            source_page,
            source_location,
            raw_text,
            purchase_date,
            supplier_name,
            total_paid,
            confidence,
            json.dumps(field_confidence, ensure_ascii=False),
            1 if legible else 0,
            json.dumps(uncertain_fields, ensure_ascii=False),
            extractor,
        ),
    )
    conn.commit()
    return int(cur.lastrowid)


def get_detected(conn: sqlite3.Connection, detected_id: int) -> sqlite3.Row | None:
    return conn.execute(
        "SELECT * FROM detected_documents WHERE id = ?", (detected_id,)
    ).fetchone()


def staged_documents(conn: sqlite3.Connection, batch_id: int) -> list[sqlite3.Row]:
    return list(
        conn.execute(
            """
            SELECT * FROM detected_documents
             WHERE batch_id = ? AND status = 'staged'
             ORDER BY id ASC
            """,
            (batch_id,),
        )
    )


def batch_summary(conn: sqlite3.Connection, batch_id: int) -> dict[str, Any]:
    row = conn.execute(
        """
        SELECT COUNT(*) AS n,
               COALESCE(SUM(total_paid), 0) AS total,
               SUM(CASE WHEN legible = 0 THEN 1 ELSE 0 END) AS ilegiveis,
               SUM(CASE WHEN supplier_name IS NULL OR TRIM(supplier_name) = ''
                          OR total_paid IS NULL THEN 1 ELSE 0 END) AS incompletos
          FROM detected_documents
         WHERE batch_id = ? AND status = 'staged'
        """,
        (batch_id,),
    ).fetchone()
    # "pendentes" = tudo que impede importar (ilegível OU faltando fornecedor/valor).
    ilegiveis = int(row["ilegiveis"] or 0)
    incompletos = int(row["incompletos"] or 0)
    pendentes = conn.execute(
        """
        SELECT COUNT(*) FROM detected_documents
         WHERE batch_id = ? AND status = 'staged'
           AND (legible = 0 OR supplier_name IS NULL OR TRIM(supplier_name) = '' OR total_paid IS NULL)
        """,
        (batch_id,),
    ).fetchone()[0]
    return {
        "count": int(row["n"]),
        "total": float(row["total"]),
        "ilegiveis": ilegiveis,
        "incompletos": incompletos,
        "pendentes": int(pendentes),
    }


def update_staged(
    conn: sqlite3.Connection,
    detected_id: int,
    *,
    purchase_date: str,
    supplier_name: str,
    total_paid: float,
    legible: bool = True,
) -> None:
    conn.execute(
        """
        UPDATE detected_documents
           SET purchase_date = ?, supplier_name = ?, total_paid = ?,
               legible = ?, updated_at = CURRENT_TIMESTAMP
         WHERE id = ? AND status = 'staged'
        """,
        (purchase_date, supplier_name, total_paid, 1 if legible else 0, detected_id),
    )
    conn.commit()


def discard_staged(conn: sqlite3.Connection, detected_id: int) -> None:
    conn.execute(
        "UPDATE detected_documents SET status = 'discarded', updated_at = CURRENT_TIMESTAMP WHERE id = ?",
        (detected_id,),
    )
    conn.commit()


def confirm_batch(conn: sqlite3.Connection, batch_id: int) -> int:
    """Promove todos os detectados 'staged' do lote para fiscal_documents."""
    rows = staged_documents(conn, batch_id)
    inserted = 0
    for row in rows:
        if not row["purchase_date"] or not row["supplier_name"] or row["total_paid"] is None:
            # Sem os três campos essenciais não confirma — permanece staged.
            continue
        conn.execute(
            """
            INSERT INTO fiscal_documents (
                detected_document_id, source_file_name, source_location,
                purchase_date, supplier_name, total_paid, confidence
            ) VALUES (?, ?, ?, ?, ?, ?, ?)
            """,
            (
                row["id"],
                row["source_file_name"],
                row["source_location"],
                row["purchase_date"],
                row["supplier_name"],
                float(row["total_paid"]),
                row["confidence"],
            ),
        )
        conn.execute(
            "UPDATE detected_documents SET status = 'confirmed', updated_at = CURRENT_TIMESTAMP WHERE id = ?",
            (row["id"],),
        )
        inserted += 1
    set_batch_status(conn, batch_id, "confirmed")
    conn.commit()
    return inserted


# --------------------------------------------------------------------------- #
# CRUD de fiscal_documents
# --------------------------------------------------------------------------- #
def create_fiscal(
    conn: sqlite3.Connection,
    *,
    purchase_date: str,
    supplier_name: str,
    total_paid: float,
    source_file_name: str = "lançamento manual",
    source_location: str = "manual",
    confidence: str = "high",
    detected_document_id: int | None = None,
) -> int:
    cur = conn.execute(
        """
        INSERT INTO fiscal_documents (
            detected_document_id, source_file_name, source_location,
            purchase_date, supplier_name, total_paid, confidence
        ) VALUES (?, ?, ?, ?, ?, ?, ?)
        """,
        (
            detected_document_id,
            source_file_name,
            source_location,
            purchase_date,
            supplier_name,
            total_paid,
            confidence,
        ),
    )
    conn.commit()
    return int(cur.lastrowid)


def get_fiscal(conn: sqlite3.Connection, doc_id: int) -> sqlite3.Row | None:
    return conn.execute(
        "SELECT * FROM fiscal_documents WHERE id = ?", (doc_id,)
    ).fetchone()


def update_fiscal(
    conn: sqlite3.Connection,
    doc_id: int,
    *,
    purchase_date: str,
    supplier_name: str,
    total_paid: float,
) -> None:
    conn.execute(
        """
        UPDATE fiscal_documents
           SET purchase_date = ?, supplier_name = ?, total_paid = ?, updated_at = CURRENT_TIMESTAMP
         WHERE id = ?
        """,
        (purchase_date, supplier_name, total_paid, doc_id),
    )
    conn.commit()


def delete_fiscal(conn: sqlite3.Connection, doc_id: int) -> None:
    conn.execute("DELETE FROM fiscal_documents WHERE id = ?", (doc_id,))
    conn.commit()


def list_fiscal(
    conn: sqlite3.Connection,
    *,
    start: str | None = None,
    end: str | None = None,
    supplier: str | None = None,
) -> list[sqlite3.Row]:
    clauses: list[str] = []
    params: list[Any] = []
    if start:
        clauses.append("purchase_date >= ?")
        params.append(start)
    if end:
        clauses.append("purchase_date <= ?")
        params.append(end)
    if supplier:
        clauses.append("supplier_name LIKE ?")
        params.append(f"%{supplier}%")
    where = f"WHERE {' AND '.join(clauses)}" if clauses else ""
    return list(
        conn.execute(
            f"SELECT * FROM fiscal_documents {where} ORDER BY purchase_date DESC, id DESC",
            params,
        )
    )


def monthly_totals(conn: sqlite3.Connection) -> list[sqlite3.Row]:
    return list(
        conn.execute(
            """
            SELECT substr(purchase_date, 1, 7) AS month, SUM(total_paid) AS total, COUNT(*) AS count
              FROM fiscal_documents
             GROUP BY substr(purchase_date, 1, 7)
             ORDER BY month ASC
            """
        )
    )


def supplier_totals(conn: sqlite3.Connection, limit: int = 10) -> list[sqlite3.Row]:
    return list(
        conn.execute(
            """
            SELECT supplier_name, SUM(total_paid) AS total, COUNT(*) AS count
              FROM fiscal_documents
             GROUP BY supplier_name
             ORDER BY total DESC
             LIMIT ?
            """,
            (limit,),
        )
    )


def overall_totals(conn: sqlite3.Connection) -> dict[str, Any]:
    row = conn.execute(
        "SELECT COUNT(*) AS n, COALESCE(SUM(total_paid), 0) AS total FROM fiscal_documents"
    ).fetchone()
    n = int(row["n"])
    total = float(row["total"])
    return {"count": n, "total": total, "avg": (total / n) if n else 0.0}