# app.py
# ──────────────────────────────────────────────────────────────────────────────
"""
AnyCoder / Shasha AI – Gradio back‑end

• Serves the custom front‑end located in static/index.html (+ static/style.css,
  static/index.js).
• Exposes ONE http POST endpoint  →  /run/predict   (Gradio api_name="predict")
  that the browser JS calls to run the model and get generated code.

All heavy lifting (model registry, provider routing, web‑search, etc.) lives in
  • models.py, inference.py, utils.py, deploy.py …
"""

from pathlib import Path
from typing import List, Tuple, Dict

import gradio as gr

# ── Local helpers ────────────────────────────────────────────────────────────
from inference   import chat_completion
from tavily_search import enhance_query_with_search
from deploy      import send_to_sandbox
from models      import AVAILABLE_MODELS, find_model, ModelInfo
from utils       import (
    extract_text_from_file,
    extract_website_content,
    history_to_messages,
    apply_search_replace_changes,
    remove_code_block,
    parse_transformers_js_output,
    format_transformers_js_output,
)

# ── System prompts keyed by language ────────────────────────────────────────
SYSTEM_PROMPTS = {
    "html": (
        "ONLY USE HTML, CSS AND JAVASCRIPT. Return exactly ONE file wrapped in "
        "```html ...```."
    ),
    "transformers.js": (
        "Generate THREE separate files (index.html • index.js • style.css) each "
        "inside its own fenced block."
    ),
}

# ── Output‑history data structure ───────────────────────────────────────────
History = List[Tuple[str, str]]  # [(user_query, generated_code), …]

# ════════════════════════════════════════════════════════════════════════════
# 1.  Backend callback hit by the JS front‑end
# ════════════════════════════════════════════════════════════════════════════
def generate(
    prompt: str,
    file_path: str | None,
    website_url: str | None,
    model_id: str,
    language: str,
    web_search: bool,
    history: History | None,
) -> Dict[str, str]:
    """
    The only public API.  Returns: { "code": <string> }
    """
    history = history or []

    # ---- Build system + user messages --------------------------------------
    sys_prompt = SYSTEM_PROMPTS.get(language, f"You are an expert {language} developer.")
    messages  = history_to_messages(history, sys_prompt)

    ctx: list[str] = [prompt.strip()]

    if file_path:
        ctx.append("[File]")
        ctx.append(extract_text_from_file(file_path)[:5_000])

    if website_url:
        html = extract_website_content(website_url)
        if not html.startswith("Error"):
            ctx.append("[Website]")
            ctx.append(html[:8_000])

    user_query = "\n\n".join(filter(None, ctx))
    user_query = enhance_query_with_search(user_query, web_search)
    messages.append({"role": "user", "content": user_query})

    # ---- Call model --------------------------------------------------------
    model: ModelInfo = find_model(model_id) or AVAILABLE_MODELS[0]
    assistant = chat_completion(model.id, messages)

    # ---- Post‑process output ----------------------------------------------
    if language == "transformers.js":
        files = parse_transformers_js_output(assistant)
        code  = format_transformers_js_output(files)
    else:
        clean = remove_code_block(assistant)
        if history and not history[-1][1].startswith("❌"):
            clean = apply_search_replace_changes(history[-1][1], clean)
        code = clean

    # (preview iframe is rendered entirely client‑side from code)
    return {"code": code}


# ════════════════════════════════════════════════════════════════════════════
# 2.  Gradio wrapper
# ════════════════════════════════════════════════════════════════════════════
# Read static front‑end
INDEX_HTML = Path("static/index.html").read_text(encoding="utf-8")

with gr.Blocks(css="body{margin:0}", title="AnyCoder AI") as demo:
    # 2‑a  Serve the custom UI
    gr.HTML(INDEX_HTML)

    # 2‑b  Invisible components acting as our JSON REST API
    with gr.Group(visible=False) as backend:
        prompt_in   = gr.Textbox()
        file_in     = gr.File()
        url_in      = gr.Textbox()
        model_in    = gr.Textbox()
        lang_in     = gr.Textbox()
        search_in   = gr.Checkbox()
        hist_state  = gr.State([])      # persists conversation on server

        code_out = gr.JSON(label="code")  # returns {"code": "..."} to the JS

    trigger = gr.Button(visible=False)
    trigger.click(
        fn=generate,
        inputs=[
            prompt_in, file_in, url_in,
            model_in, lang_in, search_in, hist_state
        ],
        outputs=[code_out],
        api_name="predict",   #  <─ POST /run/predict
    )

# ---------------------------------------------------------------------------
if __name__ == "__main__":
    demo.queue().launch()