import os
import re
import argparse
import shutil
from PIL import Image

# --- Konfiguracija skripte ---
PROJECT_ROOT = os.path.dirname(os.path.abspath(__file__)) # Predvideva, da je skripta v root direktoriju projekta

IMAGES_DIR_NAME = "images"
ORIGINAL_IMAGES_SUBDIR_NAME = "original" # Podmapa znotraj IMAGES_DIR_NAME
HTML_ROOT_DIRS = ['en', 'si', 'mk'] # Jezikovne mape, kjer se nahajajo HTML datoteke za posodobitev

WEBP_QUALITY = 80 # Kakovost kompresije za WebP (0-100). Višja številka = boljša kakovost, večja datoteka.
MAX_IMAGE_DIMENSION = 1920 # Maksimalna dimenzija (širina ali višina) za pomanjšanje, če je slika večja. Ohranijo se razmerja. Če je 0, se ne pomanjšuje.

IMAGE_EXTENSIONS_TO_OPTIMIZE = ['.jpg', '.jpeg', '.png', '.gif'] # Končnice datotek, ki jih želimo optimizirati
EXCLUDE_FILES_FROM_OPTIMIZATION = [
    '1-logo.png',       # Logotip, ki ga morda ne želimo spreminjati
    '13-whitelogo.png', # Beli logotip, ki ga morda ne želimo spreminjati
    'favicon.ico'       # Ikona, ki ni slikovni format, ki ga Pillow lahko enostavno pretvori v WebP
    # Dodaj še druga imena datotek, ki jih želiš izključiti iz optimizacije
]

# --- Pomožne funkcije ---

def optimize_image(image_path, output_path, quality, max_dim, dry_run=False):
    """
    Naloži sliko, jo po potrebi pomanjša, optimizira in pretvori v WebP format.
    """
    try:
        with Image.open(image_path) as img:
            original_size = img.size
            
            # Pretvorba v RGB, če je potrebno (WebP ne podpira npr. paletnih slik brez RGB pretvorbe)
            if img.mode in ('P', 'LA', 'RGBA'):
                if img.mode == 'RGBA':
                    # Za RGBA slike, ki so shranjene v WebP, se shrani z alfa kanalom.
                    # Če želimo brez alfa, bi morali ustvariti belo ozadje:
                    # new_img = Image.new("RGB", img.size, (255, 255, 255))
                    # new_img.paste(img, mask=img.split()[3])
                    # img = new_img
                    pass # Ohranimo RGBA za WebP z alfa kanalom
                else:
                    img = img.convert("RGB")
            
            # Pomanjšanje slike, če je prevelika
            if max_dim > 0 and (img.width > max_dim or img.height > max_dim):
                print(f"  Pomanjšujem sliko {os.path.basename(image_path)} iz {img.width}x{img.height} ...", end="")
                img.thumbnail((max_dim, max_dim), Image.LANCZOS) # Lanczos za kakovostno pomanjšanje
                print(f" na {img.width}x{img.height}")
            else:
                print(f"  Obdelujem sliko {os.path.basename(image_path)} ({img.width}x{img.height})...", end="")

            if not dry_run:
                # Shrani v WebP
                # Za RGBA WebP slike, `lossless=True` ali `quality` določita kompresijo.
                # `method` (0-6) nadzoruje hitrost/kakovost kodiranja. Višja = počasneje/boljše.
                img.save(output_path, "webp", quality=quality, method=6)
                print(f" Shrani v {os.path.basename(output_path)} (kvaliteta: {quality}).")
            else:
                print(f" DRY RUN: Shranil bi v {os.path.basename(output_path)} (kvaliteta: {quality}).")

            return True
    except FileNotFoundError:
        print(f"  Napaka: Izvorna slika '{image_path}' ni najdena.")
        return False
    except Exception as e:
        print(f"  Napaka pri optimizaciji slike '{image_path}': {e}")
        return False

def update_html_references(html_file_path, old_filename_with_ext, new_filename_with_ext, dry_run=False):
    """
    Poišče staro ime slike v HTML datoteki in ga zamenja z novim imenom WebP.
    """
    try:
        with open(html_file_path, 'r', encoding='utf-8') as f:
            content = f.read()
    except Exception as e:
        print(f"  Napaka pri branju HTML datoteke '{html_file_path}': {e}")
        return False

    original_content = content
    changed = False

    # Izdelava regularnega izraza, ki bo iskal staro ime datoteke znotraj poti
    # in ga zamenjal z novim. Poskrbimo, da ujemanje ni preveč široko.
    # Iščemo vzorce kot so src=".../staro_ime.ext", url('.../staro_ime.ext'), itd.
    
    # Prvi del ujame začetek atributa/URL-ja (npr. src=" ali url()...)
    # Drugi del ujame *katerokoli pot* pred imenom datoteke (npr. ../images/)
    # Tretji del ujame staro ime datoteke z razširitvijo
    # Četrti del ujame zaključek atributa/URL-ja
    
    # Regex pattern to match filename.ext in various HTML/CSS contexts
    # Example: 1-logo.png -> 1-logo.webp
    # It must replace only the filename, not parts of other filenames.
    
    # This pattern is specifically designed to handle common cases where image names appear
    # in src/srcset/href attributes or url() CSS functions.
    # It uses named groups for clarity and robustness.
    # Group `before_path` captures anything before the actual filename to ensure we only
    # target image references and not random text.
    # Group `path` captures the relative path (e.g., ../images/).

    # We need to escape the old filename for regex safety.
    escaped_old_filename = re.escape(old_filename_with_ext)
    
    # Pattern to find old_filename_with_ext in common image contexts.
    # This pattern looks for the filename preceded by either:
    # - `src="` or `srcset="` or `href="` followed by any path characters
    # - `url(` followed by optional quotes and any path characters
    # It attempts to capture the path prefix to preserve it.

    # This is a complex regex. Let's simplify the strategy slightly to avoid over-matching.
    # Iterate through potential contexts and replace just the filename within that context.
    
    # Contexts: src="...", srcset="...", url('...'), url("..."), url(...)
    
    patterns = [
        # For src, srcset, href attributes (usually contain path/filename.ext)
        re.compile(rf'(?P<attr>src|srcset|href)=["\'](?P<path>.*?){escaped_old_filename}(?P<end>["\'])', re.IGNORECASE),
        # For url() in CSS (can be with single, double quotes or no quotes)
        re.compile(rf'(url\([\'"]*)(?P<path>.*?){escaped_old_filename}([\'"]*\))', re.IGNORECASE)
    ]

    for pattern in patterns:
        content, num_replacements = pattern.subn(
            lambda m: f"{m.group('attr')}=\"{m.group('path')}{new_filename_with_ext}\"" if 'attr' in m.groupdict() else f"{m.group(1)}{m.group('path')}{new_filename_with_ext}{m.group(3)}",
            content
        )
        if num_replacements > 0:
            changed = True
            print(f"  Zamenjano {num_replacements} referenc za '{old_filename_with_ext}' z '{new_filename_with_ext}' v '{html_file_path}'.")

    if changed and not dry_run:
        backup_path = html_file_path + ".bak"
        try:
            shutil.copy2(html_file_path, backup_path)
            # print(f"  Varnostna kopija ustvarjena: {backup_path}") # Odkomentiraj za več izpisa
        except Exception as e:
            print(f"  Napaka pri ustvarjanju varnostne kopije za '{html_file_path}': {e}")
            return False

        try:
            with open(html_file_path, 'w', encoding='utf-8') as f:
                f.write(content)
            # print(f"  HTML datoteka posodobljena: {html_file_path}") # Odkomentiraj za več izpisa
            return True
        except Exception as e:
            print(f"  Napaka pri zapisovanju v HTML datoteko '{html_file_path}': {e}")
            return False
    elif changed and dry_run:
        print(f"  DRY RUN: HTML datoteka '{html_file_path}' bi bila posodobljena (reference za '{old_filename_with_ext}' z '{new_filename_with_ext}').")
        return True # Return true in dry_run if changes would have occurred
    else:
        # print(f"  Ni referenc za '{old_filename_with_ext}' v '{html_file_path}'.") # Odkomentiraj za več izpisa
        return False


def find_html_files(root_dir):
    """
    Rekurzivno poišče vse HTML datoteke v določenem korenskem imeniku.
    Vrne seznam absolutnih poti do datotek.
    """
    html_files = []
    for dirpath, _, filenames in os.walk(root_dir):
        for filename in filenames:
            if filename.endswith(".html"):
                html_files.append(os.path.join(dirpath, filename))
    return html_files

# --- Glavna funkcija ---

def main():
    parser = argparse.ArgumentParser(description="Skripta za optimizacijo slik (pretvorba v WebP) in posodobitev HTML referenc.")
    parser.add_argument("--dry-run", action="store_true", help="Izvede operacije, vendar ne spreminja datotek in ne premika originalnih slik.")
    args = parser.parse_args()

    images_full_path = os.path.join(PROJECT_ROOT, IMAGES_DIR_NAME)
    original_images_full_path = os.path.join(images_full_path, ORIGINAL_IMAGES_SUBDIR_NAME)

    if not os.path.isdir(images_full_path):
        print(f"Napaka: Mapa s slikami '{images_full_path}' ne obstaja. Preverite konfiguracijo.")
        return

    if not args.dry_run:
        # Ustvari mapo za originalne slike, če ne obstaja
        os.makedirs(original_images_full_path, exist_ok=True)
        print(f"Mapa za originalne slike: '{original_images_full_path}' (ustvarjena, če ni obstajala).")
    else:
        print(f"DRY RUN: Mapa za originalne slike bi bila '{original_images_full_path}'.")


    optimized_images_map = [] # Seznam slovarjev: {'old_name': 'slika.jpg', 'new_name': 'slika.webp', 'old_full_path': ..., 'new_full_path': ...}
    
    print("\n--- ZAČETEK OPTIMIZACIJE SLIK ---")
    for filename in os.listdir(images_full_path):
        if filename == ORIGINAL_IMAGES_SUBDIR_NAME:
            continue # Preskoči mapo za originalne slike
        
        file_path = os.path.join(images_full_path, filename)

        if os.path.isfile(file_path):
            name, ext = os.path.splitext(filename)
            ext = ext.lower()

            if filename in EXCLUDE_FILES_FROM_OPTIMIZATION:
                print(f"  Preskakujem izključeno datoteko: '{filename}'.")
                continue

            if ext in IMAGE_EXTENSIONS_TO_OPTIMIZE:
                new_filename = f"{name}.webp"
                new_file_path = os.path.join(images_full_path, new_filename)
                
                # Preveri, če WebP slika že obstaja in je starejša od originalne
                if os.path.exists(new_file_path) and os.path.getmtime(new_file_path) > os.path.getmtime(file_path):
                    print(f"  WebP različica '{new_filename}' že obstaja in je novejša od originala. Preskakujem optimizacijo.")
                    # Vseeno jo dodaj v mapo za posodobitev referenc
                    optimized_images_map.append({
                        'old_name': filename,
                        'new_name': new_filename,
                        'old_full_path': file_path,
                        'new_full_path': new_file_path
                    })
                    continue

                if optimize_image(file_path, new_file_path, WEBP_QUALITY, MAX_IMAGE_DIMENSION, args.dry_run):
                    optimized_images_map.append({
                        'old_name': filename,
                        'new_name': new_filename,
                        'old_full_path': file_path,
                        'new_full_path': new_file_path
                    })
                    if not args.dry_run:
                        # Premakni originalno sliko v 'original' mapo
                        try:
                            shutil.move(file_path, os.path.join(original_images_full_path, filename))
                            print(f"  Originalna slika premaknjena: '{filename}' -> '{ORIGINAL_IMAGES_SUBDIR_NAME}/'.")
                        except Exception as e:
                            print(f"  Napaka pri premikanju originalne slike '{filename}': {e}")
                    else:
                        print(f"  DRY RUN: Originalna slika '{filename}' bi bila premaknjena v '{ORIGINAL_IMAGES_SUBDIR_NAME}/'.")
                
            else:
                print(f"  Preskakujem datoteko (ni slika za optimizacijo): '{filename}'.")
        else:
            print(f"  Preskakujem (ni datoteka): '{filename}'.")

    if not optimized_images_map:
        print("\nNi slik za optimizacijo ali pa so že optimizirane. Preskakujem posodabljanje HTML referenc.")
        print("\n--- OPTIMIZACIJA SLIK ZAKLJUČENA ---")
        return

    print("\n--- ZAČETEK POSODABLJANJA HTML REFERENC ---")
    
    all_html_files = []
    for lang_dir_name in HTML_ROOT_DIRS:
        lang_full_path = os.path.join(PROJECT_ROOT, lang_dir_name)
        if os.path.isdir(lang_full_path):
            all_html_files.extend(find_html_files(lang_full_path))
        else:
            print(f"Opozorilo: Jezikovna mapa '{lang_full_path}' ne obstaja. Preskakujem iskanje HTML datotek v njej.")

    if not all_html_files:
        print("Ni najdenih HTML datotek za posodobitev referenc.")
        print("\n--- OPTIMIZACIJA SLIK ZAKLJUČENA ---")
        return

    updated_html_files_count = 0
    for html_file in all_html_files:
        file_changed = False
        for img_info in optimized_images_map:
            old_name = img_info['old_name']
            new_name = img_info['new_name']
            
            # Kliče update_html_references in preveri, ali je bila datoteka spremenjena
            if update_html_references(html_file, old_name, new_name, args.dry_run):
                file_changed = True
        
        if file_changed:
            updated_html_files_count += 1
            # print(f"  Posodobljene reference v: {html_file}") # Odkomentiraj za več izpisa
            
    print(f"\nPosodobljenih je bilo {updated_html_files_count} HTML datotek (vključno z DRY RUN).")
    print("\n--- OPTIMIZACIJA SLIK ZAKLJUČENA ---")

if __name__ == "__main__":
    main()