"""
Query history panel — logs every executed query with timestamp and status.
Persists to ~/.dbclient/history.db (SQLite).
"""
import sqlite3
import datetime
from pathlib import Path

from PyQt6.QtWidgets import (
    QWidget, QVBoxLayout, QHBoxLayout, QTableWidget, QTableWidgetItem,
    QLineEdit, QPushButton, QHeaderView, QAbstractItemView, QMenu,
    QLabel,
)
from PyQt6.QtCore import Qt, pyqtSignal
from PyQt6.QtGui import QColor, QFont

_HISTORY_DB = Path.home() / ".dbclient" / "history.db"
_MAX_HISTORY = 500


def _open_db() -> sqlite3.Connection:
    _HISTORY_DB.parent.mkdir(parents=True, exist_ok=True)
    conn = sqlite3.connect(_HISTORY_DB)
    conn.execute("""
        CREATE TABLE IF NOT EXISTS history (
            id        INTEGER PRIMARY KEY AUTOINCREMENT,
            ts        TEXT    NOT NULL,
            db_type   TEXT,
            database  TEXT,
            sql       TEXT,
            duration  REAL,
            status    TEXT
        )
    """)
    conn.commit()
    return conn


def record_query(db_type: str, database: str, sql: str,
                 duration: float, status: str = "OK") -> None:
    """Insert a history record (called from query worker result slot)."""
    try:
        conn = _open_db()
        conn.execute("""
            INSERT INTO history (ts, db_type, database, sql, duration, status)
            VALUES (?, ?, ?, ?, ?, ?)
        """, (
            datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S"),
            db_type, database, sql[:2000], round(duration, 4), status
        ))
        # Prune
        conn.execute(f"""
            DELETE FROM history WHERE id NOT IN (
                SELECT id FROM history ORDER BY id DESC LIMIT {_MAX_HISTORY}
            )
        """)
        conn.commit()
        conn.close()
    except Exception:
        pass


class QueryHistoryPanel(QWidget):
    """Shows query history and emits signals to replay queries."""

    run_query = pyqtSignal(str)   # emitted when user re-runs a history item

    def __init__(self, parent=None):
        super().__init__(parent)
        self._build_ui()
        self.refresh()

    def _build_ui(self):
        root = QVBoxLayout(self)
        root.setContentsMargins(0, 0, 0, 0)
        root.setSpacing(0)

        # Toolbar
        tb = QHBoxLayout()
        tb.setContentsMargins(6, 6, 6, 4)

        self._search = QLineEdit()
        self._search.setPlaceholderText("🔍  Search history…")
        self._search.textChanged.connect(self._filter)

        refresh_btn = QPushButton("🔄")
        refresh_btn.setFixedWidth(34)
        refresh_btn.setToolTip("Refresh")
        refresh_btn.clicked.connect(self.refresh)

        clear_btn = QPushButton("🧹")
        clear_btn.setFixedWidth(34)
        clear_btn.setToolTip("Clear all history")
        clear_btn.clicked.connect(self._clear_history)

        tb.addWidget(self._search, 1)
        tb.addWidget(refresh_btn)
        tb.addWidget(clear_btn)
        root.addLayout(tb)

        # Table
        self._table = QTableWidget(0, 5)
        self._table.setHorizontalHeaderLabels(
            ["Timestamp", "Database", "Duration", "Status", "SQL"])
        self._table.horizontalHeader().setSectionResizeMode(
            QHeaderView.ResizeMode.ResizeToContents)
        self._table.horizontalHeader().setSectionResizeMode(
            4, QHeaderView.ResizeMode.Stretch)
        self._table.verticalHeader().setDefaultSectionSize(24)
        self._table.setSelectionBehavior(
            QAbstractItemView.SelectionBehavior.SelectRows)
        self._table.setEditTriggers(QTableWidget.EditTrigger.NoEditTriggers)
        self._table.setAlternatingRowColors(True)
        self._table.setContextMenuPolicy(
            Qt.ContextMenuPolicy.CustomContextMenu)
        self._table.customContextMenuRequested.connect(self._context_menu)
        self._table.doubleClicked.connect(self._on_double_click)
        root.addWidget(self._table)

    # ── Data ─────────────────────────────────────────────────────────────────

    def refresh(self):
        self._load(self._search.text())

    def _load(self, search: str = ""):
        try:
            conn = _open_db()
            if search:
                rows = conn.execute("""
                    SELECT ts, database, duration, status, sql
                    FROM history WHERE sql LIKE ? ORDER BY id DESC
                """, (f"%{search}%",)).fetchall()
            else:
                rows = conn.execute("""
                    SELECT ts, database, duration, status, sql
                    FROM history ORDER BY id DESC
                """).fetchall()
            conn.close()
        except Exception:
            rows = []

        self._table.setRowCount(0)
        for ts, db, dur, status, sql in rows:
            r = self._table.rowCount()
            self._table.insertRow(r)
            items = [
                ts or "",
                db or "",
                f"{dur:.3f}s" if dur else "",
                status or "",
                (sql or "").replace("\n", " ")[:200],
            ]
            for c, val in enumerate(items):
                item = QTableWidgetItem(val)
                if c == 3 and status == "ERROR":
                    item.setForeground(QColor("#e78284"))
                self._table.setItem(r, c, item)

    def _filter(self, text: str):
        self._load(text)

    def _clear_history(self):
        try:
            conn = _open_db()
            conn.execute("DELETE FROM history")
            conn.commit()
            conn.close()
        except Exception:
            pass
        self._table.setRowCount(0)

    # ── Interactions ──────────────────────────────────────────────────────────

    def _on_double_click(self, idx):
        row = idx.row()
        sql_item = self._table.item(row, 4)
        if sql_item:
            self.run_query.emit(sql_item.text())

    def _context_menu(self, pos):
        row = self._table.rowAt(pos.y())
        if row < 0:
            return
        sql = self._table.item(row, 4)
        if not sql:
            return
        menu = QMenu(self)
        menu.addAction("▶ Run Query", lambda: self.run_query.emit(sql.text()))
        menu.addAction("📋 Copy SQL",  lambda: self._copy(sql.text()))
        menu.exec(self._table.viewport().mapToGlobal(pos))

    @staticmethod
    def _copy(text: str):
        from PyQt6.QtWidgets import QApplication
        QApplication.clipboard().setText(text)