import os, csv
from datetime import datetime
from pathlib import Path

from ffmpeg import FFmpeg, Progress

from lib import GalleryTable

TABLE_PATH = Path(__file__, "..", "gallery-items.csv").resolve()
MEDIA_FOLDER = Path(__file__, "..", "gallery", "media").resolve()
THUMBNAIL_FOLDER = Path(__file__, "..", "gallery", "thumbs").resolve()
THUMBNAIL_SUFFIX = "-thumb.webp"
THUMBNAIL_MAX_FRAMES = 0 # No limit. Feel free to adjust this if you're hosting long animations on there or something.

FILE_BLACKLIST = [
  # Dot files (e.g. .gitkeep, .gitignore, .DS_Store) are ignored in general.
  # Windows does not do us the courtesy of having all hidden files start with a period,
  # so I'm filtering some of the common ones out "by hand" here. 
  # It's possible that I'm missing a couple. 
  # If your gallery-items.csv winds up with entries for any files that you 
  # don't want in your gallery, please feel free to expand this list by hand.
  "Thumbs.db", # Windows Thumbnail Cache
  "Desktop.ini" # Windows Folder Settings
]

def generate_and_register_thumbnail(file_path, thumbnail_path):
  try:
    generate_thumbnail(file_path, thumbnail_path)
    table[file_name]["Thumbnail"] = thumbnail_path.name
    print("\n✅ Generated thumbnail successfully: {}".format(thumbnail_path.name))
  except Exception as error:
    print("\n⚠️ Error while generating thumbnail for {}:".format(file_path.name))
    print("{error_name}: {error}".format(error_name=type(error).__name__, error=error))
    print("Continuing on...")

def generate_thumbnail(file_path, thumbnail_path):
  ffmpeg = (
    FFmpeg()
    .option("n") # Do not overwrite existing files (we already checked for them earlier, so this is just to be sure)
    .input(file_path) # Input file
    .output(
      thumbnail_path, # Output file
      vf="scale=300:300:force_original_aspect_ratio=increase", # Resize smallest side to 300px while preserving aspect ratio
      vcodec="webp", # Webp files are TINY and load super fast. Incredible file format.
      lossless=0,
      quality=90, # Basically undetectable in a thumbnail, even for animations.
      compression_level=6, # Highest compression level, takes a little longer to process
      loop=0 # Infinite loop (e.g. for thumbnails of animated gifs)
    )
  )

  @ffmpeg.on("start") # Log ffmpeg arguments for thumbnail generation at the start
  def on_start(arguments: list[str]):
    print("Running FFmpeg with arguments:\n", arguments, "\n")

  @ffmpeg.on("progress") # Log thumbnail generation progress as it happens
  def on_progress(progress: Progress):
    print("Progress:", progress)
    if THUMBNAIL_MAX_FRAMES > 0 and progress.frame > THUMBNAIL_MAX_FRAMES:
      ffmpeg.terminate()

  ffmpeg.execute() # Go!!!

def prompt_confirmation(prompt_message):
  answer = input(prompt_message + "\n")
  return answer.lower() in ["y", "yes"] # Accept "y", "Y", "yes", "Yes" etc.

def print_horizontal_separator():
    print("--------------")

def is_file_blacklisted(file_name):
  if file_name.startswith("."):
    return True # Hidden files on Linux and Mac
  elif file_name in FILE_BLACKLIST:
    return True # Specifically blacklisted
  else:
    return False # Fine


if __name__ == "__main__": # Only do this when the script is run directly

  print("Generating thumbnails...")

  # Load existing table, if one does exists:

  if TABLE_PATH.is_file():
    table = GalleryTable.parse_table(TABLE_PATH)
  else:
    table = {}

  # Generate thumbnails and table information 
  # for all images discovered in the folder:

  for file_name in os.listdir(MEDIA_FOLDER):
    if is_file_blacklisted(file_name):
      continue

    print("Checking \"{}\"...".format(file_name))
    file_path = Path(MEDIA_FOLDER, file_name).resolve()

    if file_name in table.keys():
      # Mark the existing table entry as valid:
      table[file_name]["present"] = True 
    else:
      # Make a new table entry for images that don't have one yet:
      table[file_name] = {
        "File": file_name, 
        "Thumbnail": "", 
        "Title": file_path.stem, 
        "Description": "<Description for \"{}\" here>".format(file_name),
        "Tags (with commas in-between)": "Example Tag 1, Example Tag 2",
        "present": True
      }

    # Check whether a thumbnail already exists, 
    # or has to be generated - there are a lot of
    # potential edge cases to address here:  

    if not table[file_name]["Thumbnail"]:
      # There's no thumbnail for this image listed in the table yet...
      thumbnail_path = Path(THUMBNAIL_FOLDER, file_name + THUMBNAIL_SUFFIX).resolve()

      if thumbnail_path.is_file():
        # ...but a thumbnail with the default name already exists:
        table[file_name]["Thumbnail"] = thumbnail_path.name # Write the existing thumbnail into the table
        print("✅ Thumbnail already exists (will be added to {}).".format(TABLE_PATH))
      else:
        # ...and no thumbnail with the default name already exists:
        print("Thumbnail does not exist, generating...")
        generate_and_register_thumbnail(file_path, thumbnail_path)

    else:
      # There's a thumbnail for this image listed in the table already...
      thumbnail_path = Path(THUMBNAIL_FOLDER, table[file_name]["Thumbnail"]).resolve()

      if thumbnail_path.is_file(): 
        # ...and it does actually exist inside the THUMBNAIL_FOLDER:
        print("✅ Thumbnail already exists.")
      else:
        # ...but it doesn't actually exist inside the THUMBNAIL_FOLDER:
        print("⚠️ Thumbnail {} is listed in {}, but was not found.".format(thumbnail_path, TABLE_PATH))
        if prompt_confirmation("Generate a thumbnail with that name? [Y/n]"):
          print("Generating thumbnail...")
          generate_and_register_thumbnail(file_path, thumbnail_path)
        else:
          print("Ignoring missing thumbnail {}.".format(thumbnail_path))

    print_horizontal_separator()

  # Identify images that were deleted from the folder,
  # but not from the table, and offer to remove them:

  orphaned_entries = {name: entry for name, entry in table.items() if not entry.get("present")}

  if orphaned_entries:
    print("Found {} gallery entries missing their source images:".format(len(orphaned_entries)))
    for name, entry in orphaned_entries.items():
      print(name)
    if prompt_confirmation("Remove these orphaned entries from the gallery? [yes/no]"):
      print("Removing {} orphaned entries from gallery...".format(len(orphaned_entries)))
      for name, entry in orphaned_entries.items():
        table.pop(name)
    else:
      print("Ignoring orphaned entries. They will remain in the gallery table for you to edit later.")
    
    print_horizontal_separator()

  # Back up the existing table and write out the new one:

  if TABLE_PATH.is_file():
    print("Backing up the existing {}...".format(TABLE_PATH))
    backup_suffix = "-backup-" + datetime.now().strftime('%Y-%m-%d_%H-%M-%S')
    os.rename(TABLE_PATH, TABLE_PATH.with_stem(TABLE_PATH.stem + backup_suffix))

  print("Writing out new table...")
  try:
    GalleryTable.write_table(TABLE_PATH, table)
    print("Done all done!")
    print("Edit {} to add titles, descriptions and tags.".format(TABLE_PATH))
    print("When finished, run the other script!")
  except Exception as error:
    print("Error writing table:")
    print("{error_name}: {error}".format(error_name=type(error).__name__, error=error))

  input("Press Enter key to exit...")