Build: The PromptLibrary Class

from datetime import datetime
import json
from pathlib import Path

class PromptLibrary:
    """Manages a collection of Prompts — load, save, search, filter.

    This replaces the loose functions in helpers.py with a single object
    that handles everything related to your prompt collection.
    """

    def __init__(self, file_path="prompts.json"):
        """Set up the library with a path to the data file."""
        # Path() converts a string to a path object — cleaner than raw strings.
        self.file_path = Path(file_path)
        # Load prompts immediately when the library is created.
        self.prompts = self._load()

    def _load(self):
        """Load prompts from the JSON file into Prompt objects."""
        if not self.file_path.exists():
            return []  # no file yet — start fresh

        with open(self.file_path, "r") as f:
            raw_data = json.load(f)

        # Convert each dictionary into a Prompt object using from_dict().
        # This is where from_dict() pays off — it knows the shape of the data.
        return [Prompt.from_dict(item) for item in raw_data]

    def save(self):
        """Save all prompts back to the JSON file."""
        # Convert each Prompt object to a dict, then write to JSON.
        data = [p.to_dict() for p in self.prompts]
        with open(self.file_path, "w") as f:
            json.dump(data, f, indent=2)

    def add(self, prompt):
        """Add a Prompt to the library and save immediately."""
        self.prompts.append(prompt)
        self.save()

    def delete(self, index):
        """Delete a prompt by index. Returns the deleted Prompt or None."""
        if 0 <= index < len(self.prompts):
            removed = self.prompts.pop(index)
            self.save()
            return removed
        return None

    def search(self, query):
        """Search prompts by keyword (checks platform, shot, and prompt text)."""
        query = query.lower()
        return [
            p for p in self.prompts
            if query in p.platform.lower()
            or query in p.shot.lower()
            or query in p.prompt_text.lower()
        ]

    def filter_by_platform(self, platform):
        """Return only prompts for a specific platform."""
        return [p for p in self.prompts if p.platform.lower() == platform.lower()]

    def platform_counts(self):
        """Count prompts per platform. Returns a dictionary."""
        counts = {}
        for p in self.prompts:
            counts[p.platform] = counts.get(p.platform, 0) + 1
        return counts

    def __len__(self):
        """len(library) returns the number of prompts."""
        return len(self.prompts)

    def __iter__(self):
        """for prompt in library: — lets you loop over prompts directly."""
        return iter(self.prompts)

from models import Prompt, PromptLibrary

# --- Create a library (uses test_prompts.json so we don't touch real data) ---
library = PromptLibrary("test_prompts.json")
print(f"Loaded: {len(library)} prompts")

# --- Add some prompts ---
p1 = Prompt("Kling", "Golf swing follow-through", "Cinematic slow motion golf swing, golden hour")
p2 = Prompt("Runway", "Ocean aerial", "Aerial tracking shot over turquoise ocean")
p3 = Prompt("Kling", "Crowd reaction", "Slow motion crowd, bokeh background, stadium")

library.add(p1)
library.add(p2)
library.add(p3)

print(f"After adding 3: {len(library)} prompts")

# --- Test iteration (uses __iter__) ---
print("\nAll prompts:")
for p in library:
    print(f"  {p}")  # uses __str__ from the Prompt class

# --- Test search ---
print("\nSearch 'golf':")
for p in library.search("golf"):
    print(f"  {p}")

# --- Test filter ---
print("\nFilter Kling:")
for p in library.filter_by_platform("Kling"):
    print(f"  {p}")

# --- Platform counts ---
print("\nPlatform counts:")
print(library.platform_counts())  # {'Kling': 2, 'Runway': 1}

# --- Delete one ---
removed = library.delete(0)
print(f"\nDeleted: {removed}")
print(f"After delete: {len(library)} prompts")

# --- Test persistence: reload the file ---
library2 = PromptLibrary("test_prompts.json")
print(f"\nReloaded from disk: {len(library2)} prompts")
# Should match — the file saved after each add/delete