import fitz
import os

def hex_to_rgb(hex_color):
    hex_color = hex_color.lstrip('#')
    return tuple(int(hex_color[i:i+2], 16)/255 for i in (0, 2, 4))

def generate_certificate_pdf(name, template_bytes, output_path, name_color_hex="#000000", font_size=60, x=None, y=None, fontname="helv", fontfile=None):
    """
    Generates a certificate PDF by overlaying text.
    If x and y are provided, uses those coordinates.
    Otherwise, searches for <fullName> placeholder.
    """
    doc = fitz.open(stream=template_bytes, filetype="pdf")
    name_color = hex_to_rgb(name_color_hex)
    
    for page in doc:
        target_x, target_y = x, y
        
        # If no manual coordinates, try to find placeholder
        if target_x is None or target_y is None:
            found = False
            for inst in page.search_for("<fullName>"):
                rect = fitz.Rect(inst)
                # Calculate center of the placeholder
                name_width = fitz.get_text_length(name, fontsize=font_size, fontname=fontname, fontfile=fontfile)
                target_x = rect.x0 + (rect.width - name_width) / 2
                # For Y: use baseline position (rect.y1 is bottom of box)
                target_y = rect.y0 + rect.height / 2 + font_size / 3
                found = True
                break
            
            if not found:
                # Fallback default if nothing found and no coordinates
                page_width = page.rect.width
                page_height = page.rect.height
                rect_width = int(page_width * 0.6)
                x0_default = int((page_width - rect_width) / 2)
                name_width = fitz.get_text_length(name, fontsize=font_size, fontname=fontname, fontfile=fontfile)
                target_x = x0_default + (rect_width - name_width) / 2
                # Place at 60% down the page
                target_y = page_height * 0.6
        
        # Insert text (ensure coordinates are within page bounds)
        if target_x is not None and target_y is not None:
            # Calculate text dimensions for centering
            if fontfile and os.path.exists(fontfile):
                font = fitz.Font(fontfile=fontfile)
            else:
                font = fitz.Font(fontname)
            name_width = font.text_length(name, fontsize=font_size)
            
            # Adjust x to center the text
            insert_x = target_x - (name_width / 2)
            
            # Adjust y from center to baseline (approximate)
            # Center is target_y. Baseline is typically target_y + font_size/3
            insert_y = target_y + (font_size / 3)
            
            # Clamp coordinates to page bounds
            page_rect = page.rect
            insert_x = max(10, min(insert_x, page_rect.width - name_width - 10))
            insert_y = max(font_size, min(insert_y, page_rect.height - 10))
            
            page.insert_text(
                (insert_x, insert_y),
                name,
                fontsize=font_size,
                color=name_color,
                fontname=fontname,
                fontfile=fontfile
            )

    doc.save(output_path)
    doc.close()
    return output_path

def get_pdf_preview_image(template_bytes, name="Sample Name", name_color_hex="#000000", font_size=60, x=None, y=None, fontname="helv", fontfile=None):
    """
    Generates a preview image (PNG) of the first page of the certificate.
    Returns bytes of the PNG image.
    """
    doc = fitz.open(stream=template_bytes, filetype="pdf")
    name_color = hex_to_rgb(name_color_hex)
    page = doc[0] # Preview only first page
    
    target_x, target_y = x, y
    
    # Logic similar to generation, but just for one page and return image
    if target_x is None or target_y is None:
        found = False
        for inst in page.search_for("<fullName>"):
            rect = fitz.Rect(inst)
            name_width = fitz.get_text_length(name, fontsize=font_size, fontname=fontname, fontfile=fontfile)
            target_x = rect.x0 + (rect.width - name_width) / 2
            target_y = rect.y0 + rect.height / 2 + font_size / 3
            found = True
            break
        
        if not found:
            page_width = page.rect.width
            page_height = page.rect.height
            rect_width = int(page_width * 0.6)
            x0_default = int((page_width - rect_width) / 2)
            name_width = fitz.get_text_length(name, fontsize=font_size, fontname=fontname, fontfile=fontfile)
            target_x = x0_default + (rect_width - name_width) / 2
import fitz
import os

def hex_to_rgb(hex_color):
    hex_color = hex_color.lstrip('#')
    return tuple(int(hex_color[i:i+2], 16)/255 for i in (0, 2, 4))

def generate_certificate_pdf(name, template_bytes, output_path, name_color_hex="#000000", font_size=60, x=None, y=None, fontname="helv", fontfile=None):
    """
    Generates a certificate PDF by overlaying text.
    If x and y are provided, uses those coordinates.
    Otherwise, searches for <fullName> placeholder.
    """
    doc = fitz.open(stream=template_bytes, filetype="pdf")
    name_color = hex_to_rgb(name_color_hex)
    
    for page in doc:
        target_x, target_y = x, y
        
        # If no manual coordinates, try to find placeholder
        if target_x is None or target_y is None:
            found = False
            for inst in page.search_for("<fullName>"):
                rect = fitz.Rect(inst)
                # Calculate center of the placeholder
                if fontfile and os.path.exists(fontfile):
                    font = fitz.Font(fontfile=fontfile)
                else:
                    font = fitz.Font(fontname)
                name_width = font.text_length(name, fontsize=font_size)
                target_x = rect.x0 + (rect.width - name_width) / 2
                # For Y: use baseline position (rect.y1 is bottom of box)
                target_y = rect.y0 + rect.height / 2 + font_size / 3
                found = True
                break
            
            if not found:
                # Fallback default if nothing found and no coordinates
                page_width = page.rect.width
                page_height = page.rect.height
                rect_width = int(page_width * 0.6)
                x0_default = int((page_width - rect_width) / 2)
                if fontfile and os.path.exists(fontfile):
                    font = fitz.Font(fontfile=fontfile)
                else:
                    font = fitz.Font(fontname)
                name_width = font.text_length(name, fontsize=font_size)
                target_x = x0_default + (rect_width - name_width) / 2
                # Place at 60% down the page
                target_y = page_height * 0.6
        
        # Insert text (ensure coordinates are within page bounds)
        if target_x is not None and target_y is not None:
            # Calculate text dimensions for centering
            if fontfile and os.path.exists(fontfile):
                font = fitz.Font(fontfile=fontfile)
            else:
                font = fitz.Font(fontname)
            name_width = font.text_length(name, fontsize=font_size)
            
            # Adjust x to center the text
            insert_x = target_x - (name_width / 2)
            
            # Adjust y from center to baseline (approximate)
            # Center is target_y. Baseline is typically target_y + font_size/3
            insert_y = target_y + (font_size / 3)
            
            # Clamp coordinates to page bounds
            page_rect = page.rect
            insert_x = max(10, min(insert_x, page_rect.width - name_width - 10))
            insert_y = max(font_size, min(insert_y, page_rect.height - 10))
            
            page.insert_text(
                (insert_x, insert_y),
                name,
                fontsize=font_size,
                color=name_color,
                fontname=fontname,
                fontfile=fontfile
            )

    doc.save(output_path)
    doc.close()
    return output_path

def get_pdf_preview_image(template_bytes, name="Sample Name", name_color_hex="#000000", font_size=60, x=None, y=None, fontname="helv", fontfile=None):
    """
    Generates a preview image (PNG) of the first page of the certificate.
    Returns bytes of the PNG image.
    """
    doc = fitz.open(stream=template_bytes, filetype="pdf")
    name_color = hex_to_rgb(name_color_hex)
    page = doc[0] # Preview only first page
    
    target_x, target_y = x, y
    
    # Logic similar to generation, but just for one page and return image
    if target_x is None or target_y is None:
        found = False
        for inst in page.search_for("<fullName>"):
            rect = fitz.Rect(inst)
            if fontfile and os.path.exists(fontfile):
                font = fitz.Font(fontfile=fontfile)
            else:
                font = fitz.Font(fontname)
            name_width = font.text_length(name, fontsize=font_size)
            target_x = rect.x0 + (rect.width - name_width) / 2
            target_y = rect.y0 + rect.height / 2 + font_size / 3
            found = True
            break
        
        if not found:
            page_width = page.rect.width
            page_height = page.rect.height
            rect_width = int(page_width * 0.6)
            x0_default = int((page_width - rect_width) / 2)
            if fontfile and os.path.exists(fontfile):
                font = fitz.Font(fontfile=fontfile)
            else:
                font = fitz.Font(fontname)
            name_width = font.text_length(name, fontsize=font_size)
            target_x = x0_default + (rect_width - name_width) / 2
            target_y = page_height * 0.6

    if target_x is not None and target_y is not None:
        # Calculate text dimensions for centering
        if fontfile and os.path.exists(fontfile):
            font = fitz.Font(fontfile=fontfile)
        else:
            font = fitz.Font(fontname)
        name_width = font.text_length(name, fontsize=font_size)
        
        # Adjust x to center the text
        insert_x = target_x - (name_width / 2)
        
        # Adjust y from center to baseline (approximate)
        # Center is target_y. Baseline is typically target_y + font_size/3
        insert_y = target_y + (font_size / 3)
        
        # Clamp coordinates to page bounds
        page_rect = page.rect
        insert_x = max(10, min(insert_x, page_rect.width - name_width - 10))
        insert_y = max(font_size, min(insert_y, page_rect.height - 10))
        
        page.insert_text(
            (insert_x, insert_y),
            name,
            fontsize=font_size,
            color=name_color,
            fontname=fontname,
            fontfile=fontfile
        )
    
    pix = page.get_pixmap()
    img_bytes = pix.tobytes("png")
    doc.close()
    return img_bytes