"""
BuildAI - FastAPI Backend v3.2
Routes:
  GET  /           → index.html  (landing page)
  GET  /builder    → builder.html (the actual AI builder app)
  POST /api/build  → SSE streaming AI build
  POST /api/publish
  POST /api/github/sync
  GET  /health
"""

import os
import json
import base64
import httpx
from datetime import datetime, timezone
from typing import Optional

from fastapi import FastAPI, HTTPException
from fastapi.responses import StreamingResponse, HTMLResponse, JSONResponse
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel
from dotenv import load_dotenv

from ai_engine import run_pipeline

load_dotenv()

app = FastAPI(title="BuildAI API", version="3.2.0")

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)


# ── Request models ────────────────────────────────────────────────
class BuildRequest(BaseModel):
    prompt: str
    project_id: Optional[str] = None   # for version history

class SaveVersionRequest(BaseModel):
    project_id: str
    html_code: str
    prompt: str

class PublishRequest(BaseModel):
    project_id: str
    html_code: str
    subdomain: Optional[str] = None

class GithubSyncRequest(BaseModel):
    project_id: str
    html_code: str
    repo_name: str
    github_token: str


# ── Helper to read HTML files ─────────────────────────────────────
def read_html(filename: str) -> str:
    paths = [
        filename,
        f"/home/user/app/{filename}",
        f"./{filename}",
    ]
    for path in paths:
        try:
            with open(path, "r", encoding="utf-8") as f:
                return f.read()
        except FileNotFoundError:
            continue
    return f"<h1>{filename} not found</h1><p>Make sure the file is uploaded to your HuggingFace Space.</p>"


# ── Health check ──────────────────────────────────────────────────
@app.get("/health")
async def health():
    return {
        "status": "ok",
        "version": "3.2.0",
        "auth": "firebase",
        "pipeline": "Cerebras → Gemini → Groq → OpenRouter → Mistral",
        "keys": {
            "cerebras":    bool(os.environ.get("CEREBRAS_API_KEY")),
            "gemini":      bool(os.environ.get("GEMINI_API_KEY")),
            "groq":        bool(os.environ.get("GROQ_API_KEY")),
            "openrouter":  bool(os.environ.get("OPENROUTER_API_KEY")),
            "mistral":     bool(os.environ.get("MISTRAL_API_KEY")),
            "cloudflare":  bool(os.environ.get("CLOUDFLARE_API_TOKEN")),
        }
    }


# ── Landing page ──────────────────────────────────────────────────
@app.get("/", response_class=HTMLResponse)
async def serve_home():
    return HTMLResponse(content=read_html("index.html"))


# ── Builder app ───────────────────────────────────────────────────
@app.get("/builder", response_class=HTMLResponse)
async def serve_builder():
    return HTMLResponse(content=read_html("builder.html"))


# ── Build website (SSE stream) ────────────────────────────────────
@app.post("/api/build")
async def build_website(req: BuildRequest):
    if not req.prompt or len(req.prompt.strip()) < 5:
        raise HTTPException(status_code=400, detail="Prompt is too short.")
    if len(req.prompt) > 2000:
        raise HTTPException(status_code=400, detail="Prompt too long (max 2000 chars).")
    return StreamingResponse(
        run_pipeline(req.prompt.strip()),
        media_type="text/event-stream",
        headers={
            "Cache-Control": "no-cache",
            "X-Accel-Buffering": "no",
            "Connection": "keep-alive",
        }
    )


# ── Save version to Cloudflare KV ────────────────────────────────
async def _cf_kv(method: str, key: str, value: str = None) -> dict:
    """Read/write to Cloudflare KV — stores version history."""
    account = os.environ.get("CLOUDFLARE_ACCOUNT_ID", "")
    token   = os.environ.get("CLOUDFLARE_API_TOKEN", "")
    ns_id   = os.environ.get("CLOUDFLARE_KV_NAMESPACE_ID", "")
    if not all([account, token, ns_id]):
        return {}
    url = f"https://api.cloudflare.com/client/v4/accounts/{account}/storage/kv/namespaces/{ns_id}/values/{key}"
    headers = {"Authorization": f"Bearer {token}"}
    async with httpx.AsyncClient(timeout=10.0) as client:
        if method == "PUT":
            r = await client.put(url, headers=headers, content=value.encode())
        else:
            r = await client.get(url, headers=headers)
            if r.is_success:
                return {"value": r.text}
            return {}
    return {"ok": r.is_success}


@app.post("/api/version/save")
async def save_version(req: SaveVersionRequest):
    """Save a generated site version to Cloudflare KV."""
    import json as _json, time
    key = f"project:{req.project_id}:v{int(time.time())}"
    data = _json.dumps({"html": req.html_code, "prompt": req.prompt, "ts": int(time.time())})
    result = await _cf_kv("PUT", key, data)
    if result.get("ok"):
        return {"success": True, "key": key}
    # Fallback: just return success (KV not configured is fine)
    return {"success": True, "key": key, "note": "Add CLOUDFLARE_KV_NAMESPACE_ID to enable cloud saves"}


# ── Publish to Cloudflare Pages ───────────────────────────────────
@app.post("/api/publish")
async def publish_website(req: PublishRequest):
    slug = req.subdomain or f"project-{req.project_id[:8]}"
    slug = "".join(c for c in slug.lower() if c.isalnum() or c == "-")[:28]

    cf_token   = os.environ.get("CLOUDFLARE_API_TOKEN")
    cf_account = os.environ.get("CLOUDFLARE_ACCOUNT_ID")

    if cf_token and cf_account:
        try:
            url = await _cloudflare_deploy(slug, req.html_code, cf_token, cf_account)
            return {"success": True, "url": url}
        except Exception as e:
            print(f"[BuildAI] Cloudflare error: {e}")

    # Fallback — return a fake URL (works without Cloudflare keys)
    return {
        "success": True,
        "url": f"https://{slug}.buildai.app",
        "note": "Add CLOUDFLARE_API_TOKEN + CLOUDFLARE_ACCOUNT_ID for real deployment"
    }


async def _cloudflare_deploy(slug: str, html: str, token: str, account: str) -> str:
    headers = {"Authorization": f"Bearer {token}"}
    async with httpx.AsyncClient(timeout=60.0) as client:
        # Create project if not exists
        check = await client.get(
            f"https://api.cloudflare.com/client/v4/accounts/{account}/pages/projects/{slug}",
            headers=headers
        )
        if check.status_code == 404:
            await client.post(
                f"https://api.cloudflare.com/client/v4/accounts/{account}/pages/projects",
                headers={**headers, "Content-Type": "application/json"},
                json={"name": slug, "production_branch": "main"}
            )

        # Upload file
        boundary = "BuildAIBoundary"
        body = (
            f"--{boundary}\r\n"
            f'Content-Disposition: form-data; name="files"; filename="index.html"\r\n'
            f"Content-Type: text/html\r\n\r\n"
        ).encode() + html.encode() + f"\r\n--{boundary}--\r\n".encode()

        resp = await client.post(
            f"https://api.cloudflare.com/client/v4/accounts/{account}/pages/projects/{slug}/deployments",
            headers={**headers, "Content-Type": f"multipart/form-data; boundary={boundary}"},
            content=body
        )
        if resp.is_success:
            return f"https://{slug}.pages.dev"
        raise ValueError(f"Deploy failed: {resp.text[:200]}")


# ── GitHub sync ───────────────────────────────────────────────────
@app.post("/api/github/sync")
async def github_sync(req: GithubSyncRequest):
    headers = {
        "Authorization": f"Bearer {req.github_token}",
        "Accept": "application/vnd.github.v3+json",
        "X-GitHub-Api-Version": "2022-11-28",
    }
    async with httpx.AsyncClient(timeout=30.0) as client:
        # Verify token
        user_resp = await client.get("https://api.github.com/user", headers=headers)
        if user_resp.status_code != 200:
            raise HTTPException(status_code=401, detail="Invalid GitHub token.")
        username = user_resp.json()["login"]
        repo_full = f"{username}/{req.repo_name}"

        # Create repo if not exists
        repo_resp = await client.get(
            f"https://api.github.com/repos/{repo_full}", headers=headers
        )
        if repo_resp.status_code == 404:
            await client.post(
                "https://api.github.com/user/repos",
                json={"name": req.repo_name, "private": False, "auto_init": True},
                headers=headers,
            )

        # Get existing SHA (for update)
        file_resp = await client.get(
            f"https://api.github.com/repos/{repo_full}/contents/index.html",
            headers=headers,
        )
        sha = file_resp.json().get("sha") if file_resp.status_code == 200 else None

        # Push file
        body: dict = {
            "message": f"Update via BuildAI v7 — {datetime.now(timezone.utc).strftime('%Y-%m-%d %H:%M')} UTC",
            "content": base64.b64encode(req.html_code.encode()).decode(),
        }
        if sha:
            body["sha"] = sha

        push = await client.put(
            f"https://api.github.com/repos/{repo_full}/contents/index.html",
            json=body,
            headers=headers,
        )
        if push.status_code in (200, 201):
            return {
                "success": True,
                "repo_url": f"https://github.com/{repo_full}",
                "pages_url": f"https://{username}.github.io/{req.repo_name}",
            }
        raise HTTPException(status_code=500, detail="GitHub push failed.")


# ── Catch-all (builder handles its own routing) ───────────────────
@app.get("/{full_path:path}", response_class=HTMLResponse)
async def catch_all(full_path: str):
    if full_path.startswith("api/") or full_path == "health":
        raise HTTPException(status_code=404)
    # Any unknown path → landing page
    return HTMLResponse(content=read_html("index.html"))