"""Widget de visualisation PDF avec pypdfium2 — V2.5 avec selection redimensionnable."""

from PyQt6.QtWidgets import (QWidget, QVBoxLayout, QLabel,
                              QScrollArea, QSizePolicy, QApplication)
from PyQt6.QtGui import (QImage, QPixmap, QWheelEvent, QPainter, QPen, QColor,
                          QMouseEvent, QCursor, QBrush)
from PyQt6.QtCore import Qt, pyqtSignal, QRect, QPoint, QSize
import pypdfium2 as pdfium

HANDLE_SIZE = 8  # taille des poignees de redimensionnement


class SelectableImageLabel(QLabel):
    """QLabel avec rectangle de selection redimensionnable par les angles."""

    selection_changed = pyqtSignal(float, float, float, float)
    selection_done = pyqtSignal()

    def __init__(self, parent=None):
        super().__init__(parent)
        self._select_mode = False
        self._has_selection = False
        self._rect = QRect()
        self._drag_mode = None  # None, "create", "move", "tl", "tr", "bl", "br", "t", "b", "l", "r"
        self._drag_start = QPoint()
        self._drag_rect_start = QRect()

    def set_select_mode(self, enabled):
        self._select_mode = enabled
        if enabled:
            self.setCursor(Qt.CursorShape.CrossCursor)
        else:
            self.setCursor(Qt.CursorShape.ArrowCursor)

    def clear_selection(self):
        self._has_selection = False
        self._rect = QRect()
        self.update()

    def set_selection_from_margins(self, left_ratio, top_ratio, right_ratio, bottom_ratio):
        if not self.pixmap():
            return
        pm = self.pixmap()
        img_w, img_h = pm.width(), pm.height()
        off_x, off_y = self._img_offset()
        x1 = off_x + int(left_ratio * img_w)
        y1 = off_y + int(top_ratio * img_h)
        x2 = off_x + int(right_ratio * img_w)
        y2 = off_y + int(bottom_ratio * img_h)
        self._rect = QRect(QPoint(x1, y1), QPoint(x2, y2)).normalized()
        self._has_selection = True
        self.update()

    def _img_offset(self):
        if not self.pixmap():
            return 0, 0
        pm = self.pixmap()
        return max(0, (self.width() - pm.width()) // 2), max(0, (self.height() - pm.height()) // 2)

    def _handle_rects(self):
        """Retourne les rectangles des 8 poignees."""
        if not self._has_selection:
            return {}
        r = self._rect.normalized()
        hs = HANDLE_SIZE
        return {
            "tl": QRect(r.left() - hs, r.top() - hs, hs * 2, hs * 2),
            "tr": QRect(r.right() - hs, r.top() - hs, hs * 2, hs * 2),
            "bl": QRect(r.left() - hs, r.bottom() - hs, hs * 2, hs * 2),
            "br": QRect(r.right() - hs, r.bottom() - hs, hs * 2, hs * 2),
            "t": QRect(r.center().x() - hs, r.top() - hs, hs * 2, hs * 2),
            "b": QRect(r.center().x() - hs, r.bottom() - hs, hs * 2, hs * 2),
            "l": QRect(r.left() - hs, r.center().y() - hs, hs * 2, hs * 2),
            "r": QRect(r.right() - hs, r.center().y() - hs, hs * 2, hs * 2),
        }

    def _cursor_for_handle(self, handle):
        cursors = {
            "tl": Qt.CursorShape.SizeFDiagCursor,
            "br": Qt.CursorShape.SizeFDiagCursor,
            "tr": Qt.CursorShape.SizeBDiagCursor,
            "bl": Qt.CursorShape.SizeBDiagCursor,
            "t": Qt.CursorShape.SizeVerCursor,
            "b": Qt.CursorShape.SizeVerCursor,
            "l": Qt.CursorShape.SizeHorCursor,
            "r": Qt.CursorShape.SizeHorCursor,
        }
        return cursors.get(handle, Qt.CursorShape.CrossCursor)

    def mousePressEvent(self, event):
        if not self._select_mode or event.button() != Qt.MouseButton.LeftButton:
            return super().mousePressEvent(event)

        pos = event.pos()
        self._drag_start = pos
        self._drag_rect_start = QRect(self._rect)

        # Verifier si on clique sur une poignee
        if self._has_selection:
            for name, hr in self._handle_rects().items():
                if hr.contains(pos):
                    self._drag_mode = name
                    return
            # Clic dans le rectangle = deplacer
            if self._rect.normalized().contains(pos):
                self._drag_mode = "move"
                return

        # Nouveau rectangle
        self._drag_mode = "create"
        self._rect = QRect(pos, pos)
        self._has_selection = True
        self.update()

    def mouseMoveEvent(self, event):
        pos = event.pos()

        if not self._select_mode:
            return super().mouseMoveEvent(event)

        # Hover : changer le curseur sur les poignees
        if not self._drag_mode and self._has_selection:
            for name, hr in self._handle_rects().items():
                if hr.contains(pos):
                    self.setCursor(self._cursor_for_handle(name))
                    return
            if self._rect.normalized().contains(pos):
                self.setCursor(Qt.CursorShape.SizeAllCursor)
                return
            self.setCursor(Qt.CursorShape.CrossCursor)
            return

        if not self._drag_mode:
            return

        dx = pos.x() - self._drag_start.x()
        dy = pos.y() - self._drag_start.y()
        r = QRect(self._drag_rect_start)

        if self._drag_mode == "create":
            self._rect = QRect(self._drag_start, pos).normalized()
        elif self._drag_mode == "move":
            self._rect = r.translated(dx, dy)
        elif self._drag_mode == "tl":
            self._rect = QRect(QPoint(r.left() + dx, r.top() + dy), r.bottomRight()).normalized()
        elif self._drag_mode == "tr":
            self._rect = QRect(QPoint(r.left(), r.top() + dy), QPoint(r.right() + dx, r.bottom())).normalized()
        elif self._drag_mode == "bl":
            self._rect = QRect(QPoint(r.left() + dx, r.top()), QPoint(r.right(), r.bottom() + dy)).normalized()
        elif self._drag_mode == "br":
            self._rect = QRect(r.topLeft(), QPoint(r.right() + dx, r.bottom() + dy)).normalized()
        elif self._drag_mode == "t":
            self._rect = QRect(QPoint(r.left(), r.top() + dy), r.bottomRight()).normalized()
        elif self._drag_mode == "b":
            self._rect = QRect(r.topLeft(), QPoint(r.right(), r.bottom() + dy)).normalized()
        elif self._drag_mode == "l":
            self._rect = QRect(QPoint(r.left() + dx, r.top()), r.bottomRight()).normalized()
        elif self._drag_mode == "r":
            self._rect = QRect(r.topLeft(), QPoint(r.right() + dx, r.bottom())).normalized()

        self.update()
        self._emit_ratios()

    def mouseReleaseEvent(self, event):
        if self._drag_mode:
            self._drag_mode = None
            self._emit_ratios()
            self.selection_done.emit()
            self.update()
        else:
            super().mouseReleaseEvent(event)

    def _emit_ratios(self):
        if not self.pixmap() or not self._has_selection:
            return
        pm = self.pixmap()
        img_w, img_h = pm.width(), pm.height()
        if img_w <= 0 or img_h <= 0:
            return
        off_x, off_y = self._img_offset()
        r = self._rect.normalized()

        left = max(0, min(1, (r.left() - off_x) / img_w))
        top = max(0, min(1, (r.top() - off_y) / img_h))
        right = max(0, min(1, (r.right() - off_x) / img_w))
        bottom = max(0, min(1, (r.bottom() - off_y) / img_h))

        self.selection_changed.emit(left, top, right, bottom)

    def paintEvent(self, event):
        super().paintEvent(event)
        if not self._has_selection or self._rect.isNull():
            return

        painter = QPainter(self)
        r = self._rect.normalized()
        full = self.rect()

        # Zone sombre en dehors
        painter.setBrush(QColor(0, 0, 0, 80))
        painter.setPen(Qt.PenStyle.NoPen)
        painter.drawRect(full.left(), full.top(), full.width(), r.top() - full.top())
        painter.drawRect(full.left(), r.bottom(), full.width(), full.bottom() - r.bottom())
        painter.drawRect(full.left(), r.top(), r.left() - full.left(), r.height())
        painter.drawRect(r.right(), r.top(), full.right() - r.right(), r.height())

        # Cadre
        pen = QPen(QColor(0, 180, 216), 2, Qt.PenStyle.SolidLine)
        painter.setPen(pen)
        painter.setBrush(Qt.BrushStyle.NoBrush)
        painter.drawRect(r)

        # Poignees
        painter.setBrush(QColor(255, 255, 255))
        painter.setPen(QPen(QColor(0, 180, 216), 1))
        for hr in self._handle_rects().values():
            painter.drawRect(hr)

        # Dimensions
        if self.pixmap():
            pm = self.pixmap()
            img_w, img_h = pm.width(), pm.height()
            off_x, off_y = self._img_offset()
            if img_w > 0 and img_h > 0:
                w_pct = r.width() / img_w * 100
                h_pct = r.height() / img_h * 100
                painter.setPen(QColor(0, 180, 216))
                painter.drawText(r.left() + 4, r.top() - 6,
                    f"{w_pct:.0f}% x {h_pct:.0f}%")

        painter.end()


class PdfViewer(QWidget):
    """Widget d'apercu PDF avec zoom molette, navigation et selection."""

    page_changed = pyqtSignal(int, int)
    selection_changed = pyqtSignal(float, float, float, float)
    selection_done = pyqtSignal()

    def __init__(self, parent=None):
        super().__init__(parent)
        self._pdf = None
        self._pdf_path = None
        self._current_page = 0
        self._total_pages = 0
        self._zoom = 1.0
        self._page_width_pt = 0
        self._page_height_pt = 0
        self._setup_ui()

    def _setup_ui(self):
        layout = QVBoxLayout(self)
        layout.setContentsMargins(0, 0, 0, 0)
        layout.setSpacing(0)

        self._scroll = QScrollArea()
        self._scroll.setWidgetResizable(True)
        self._scroll.setAlignment(Qt.AlignmentFlag.AlignCenter)
        self._scroll.setStyleSheet("QScrollArea { background: #d0d0d0; border: none; }")

        self._image_label = SelectableImageLabel()
        self._image_label.setAlignment(Qt.AlignmentFlag.AlignCenter)
        self._image_label.setSizePolicy(QSizePolicy.Policy.Ignored, QSizePolicy.Policy.Ignored)
        self._image_label.setStyleSheet("background: #d0d0d0;")
        self._image_label.selection_changed.connect(self.selection_changed.emit)
        self._image_label.selection_done.connect(self.selection_done.emit)
        self._scroll.setWidget(self._image_label)

        self._scroll.wheelEvent = self._on_wheel
        layout.addWidget(self._scroll, 1)

    def set_select_mode(self, enabled):
        self._image_label.set_select_mode(enabled)

    def clear_selection(self):
        self._image_label.clear_selection()

    def show_selection(self, left_ratio, top_ratio, right_ratio, bottom_ratio):
        self._image_label.set_selection_from_margins(left_ratio, top_ratio, right_ratio, bottom_ratio)

    def _on_wheel(self, event):
        if event.modifiers() & Qt.KeyboardModifier.ControlModifier:
            delta = event.angleDelta().y()
            if delta > 0:
                self._zoom = min(self._zoom * 1.15, 5.0)
            else:
                self._zoom = max(self._zoom / 1.15, 0.2)
            self._render_page()
        else:
            if event.angleDelta().y() < 0:
                self.next_page()
            elif event.angleDelta().y() > 0:
                self.prev_page()

    def load_pdf(self, path):
        try:
            self._pdf_path = path
            self._pdf = pdfium.PdfDocument(path)
            self._total_pages = len(self._pdf)
            self._current_page = 0
            self._zoom_fit()
            self._render_page()
        except Exception as e:
            self._image_label.setText(f"Erreur: {e}")

    def load_pdf_bytes(self, data):
        try:
            self._pdf = pdfium.PdfDocument(data)
            self._total_pages = len(self._pdf)
            self._current_page = 0
            self._zoom_fit()
            self._render_page()
        except Exception as e:
            self._image_label.setText(f"Erreur: {e}")

    def _render_page(self):
        if not self._pdf or self._current_page >= self._total_pages:
            return
        page = self._pdf[self._current_page]
        self._page_width_pt, self._page_height_pt = page.get_size()
        scale = 150 / 72 * self._zoom
        bitmap = page.render(scale=scale)
        pil_image = bitmap.to_pil()
        data = pil_image.tobytes("raw", "RGBA")
        qimage = QImage(data, pil_image.width, pil_image.height, QImage.Format.Format_RGBA8888)
        pixmap = QPixmap.fromImage(qimage)
        self._image_label.setPixmap(pixmap)
        self._image_label.adjustSize()
        self.page_changed.emit(self._current_page, self._total_pages)

    def _zoom_fit(self):
        if not self._pdf or self._current_page >= self._total_pages:
            return
        page = self._pdf[self._current_page]
        pw, ph = page.get_size()
        vw = self._scroll.viewport().width() - 20
        vh = self._scroll.viewport().height() - 20
        if vw <= 0 or vh <= 0:
            self._zoom = 1.0
            return
        self._zoom = min(vw / pw, vh / ph) * (72 / 150)

    def prev_page(self):
        if self._current_page > 0:
            self._current_page -= 1
            self._render_page()

    def next_page(self):
        if self._current_page < self._total_pages - 1:
            self._current_page += 1
            self._render_page()

    def go_to_page(self, page_index):
        if 0 <= page_index < self._total_pages and page_index != self._current_page:
            self._current_page = page_index
            self._render_page()

    def zoom_in(self):
        self._zoom = min(self._zoom * 1.25, 5.0)
        self._render_page()

    def zoom_out(self):
        self._zoom = max(self._zoom / 1.25, 0.2)
        self._render_page()

    def zoom_fit(self):
        self._zoom_fit()
        self._render_page()

    def refresh(self):
        self._render_page()

    def get_page_thumbnail(self, page_index, width=120):
        if not self._pdf or page_index >= self._total_pages:
            return None
        page = self._pdf[page_index]
        pw, ph = page.get_size()
        scale = width / pw
        bitmap = page.render(scale=scale)
        pil_image = bitmap.to_pil()
        data = pil_image.tobytes("raw", "RGBA")
        qimage = QImage(data, pil_image.width, pil_image.height, QImage.Format.Format_RGBA8888)
        return QPixmap.fromImage(qimage)

    @property
    def current_page(self):
        return self._current_page

    @property
    def total_pages(self):
        return self._total_pages

    @property
    def zoom_level(self):
        return self._zoom

    @property
    def pdf_path(self):
        return self._pdf_path

    @property
    def page_width_pt(self):
        return self._page_width_pt

    @property
    def page_height_pt(self):
        return self._page_height_pt