from PySide6.QtWidgets import (QWidget, QVBoxLayout, QHBoxLayout, QPushButton,
                               QLabel, QScrollArea, QSplitter, QTabWidget)
from PySide6.QtCore import Qt, Signal
from PySide6.QtGui import QImage, QPixmap
import fitz
from database import get_session
from models import Document
from comments import CommentsList
from preferences import Preferences

class DocumentViewer(QWidget):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.current_document = None
        self.current_page = 0
        self.preferences = Preferences()
        self.setup_ui()
    
    def setup_ui(self):
        layout = QVBoxLayout(self)
        
        # Toolbar
        toolbar = QHBoxLayout()
        
        self.prev_btn = QPushButton("Anterior")
        self.prev_btn.clicked.connect(self.prev_page)
        toolbar.addWidget(self.prev_btn)
        
        self.page_label = QLabel("Página 0 de 0")
        toolbar.addWidget(self.page_label)
        
        self.next_btn = QPushButton("Próxima")
        self.next_btn.clicked.connect(self.next_page)
        toolbar.addWidget(self.next_btn)
        
        toolbar.addStretch()
        
        self.zoom_in_btn = QPushButton("Zoom +")
        self.zoom_in_btn.clicked.connect(self.zoom_in)
        toolbar.addWidget(self.zoom_in_btn)
        
        self.zoom_out_btn = QPushButton("Zoom -")
        self.zoom_out_btn.clicked.connect(self.zoom_out)
        toolbar.addWidget(self.zoom_out_btn)
        
        layout.addLayout(toolbar)
        
        # Main content area
        splitter = QSplitter(Qt.Horizontal)
        
        # Document view
        self.scroll_area = QScrollArea()
        self.scroll_area.setWidgetResizable(True)
        self.document_label = QLabel()
        self.document_label.setAlignment(Qt.AlignCenter)
        self.scroll_area.setWidget(self.document_label)
        splitter.addWidget(self.scroll_area)
        
        # Side panel with tabs
        side_panel = QTabWidget()
        
        # Comments tab
        self.comments_list = CommentsList()
        side_panel.addTab(self.comments_list, "Comentários")
        
        splitter.addWidget(side_panel)
        
        # Set initial splitter sizes
        splitter.setSizes([int(self.width() * 0.7), int(self.width() * 0.3)])
        
        layout.addWidget(splitter)
        
        self.zoom_level = 1.0
        self.doc = None
        self.update_navigation()
    
    def load_document(self, doc_id):
        try:
            session = get_session()
            document = session.query(Document).get(doc_id)
            
            if document and document.file_path:
                self.current_document = doc_id
                self.doc = fitz.open(document.file_path)
                self.current_page = 0
                self.zoom_level = 1.0
                self.update_page()
                self.update_navigation()
                
                # Load comments
                self.comments_list.load_document(doc_id)
                
                # Add to recent documents if auto_preview is enabled
                if self.preferences.get("auto_preview"):
                    from preferences import RecentDocuments
                    recent = RecentDocuments(self.preferences)
                    recent.add_document(doc_id, document.file_name)
            
            session.close()
        except Exception as e:
            print(f"Error loading document: {str(e)}")
    
    def update_page(self):
        if not self.doc:
            return
        
        try:
            page = self.doc[self.current_page]
            zoom = self.zoom_level
            
            # Adjust zoom based on preview size preference
            preview_size = self.preferences.get("preview_size")
            if preview_size == "small":
                zoom *= 0.8
            elif preview_size == "large":
                zoom *= 1.2
            
            mat = fitz.Matrix(zoom, zoom)
            pix = page.get_pixmap(matrix=mat)
            
            img = QImage(pix.samples, pix.width, pix.height,
                        pix.stride, QImage.Format_RGB888)
            
            pixmap = QPixmap.fromImage(img)
            self.document_label.setPixmap(pixmap)
            
            self.page_label.setText(f"Página {self.current_page + 1} de {len(self.doc)}")
        except Exception as e:
            print(f"Error updating page: {str(e)}")
    
    def update_navigation(self):
        has_doc = self.doc is not None
        has_prev = has_doc and self.current_page > 0
        has_next = has_doc and self.current_page < len(self.doc) - 1
        
        self.prev_btn.setEnabled(has_prev)
        self.next_btn.setEnabled(has_next)
        self.zoom_in_btn.setEnabled(has_doc)
        self.zoom_out_btn.setEnabled(has_doc)
    
    def prev_page(self):
        if self.doc and self.current_page > 0:
            self.current_page -= 1
            self.update_page()
            self.update_navigation()
    
    def next_page(self):
        if self.doc and self.current_page < len(self.doc) - 1:
            self.current_page += 1
            self.update_page()
            self.update_navigation()
    
    def zoom_in(self):
        self.zoom_level *= 1.2
        self.update_page()
    
    def zoom_out(self):
        self.zoom_level /= 1.2
        self.update_page()
    
    def closeEvent(self, event):
        if self.doc:
            self.doc.close()
        super().closeEvent(event)