from __future__ import annotations

import json
import os
from pathlib import Path
from typing import Any, Dict

from dotenv import load_dotenv
from fastapi import FastAPI, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import FileResponse, PlainTextResponse

from backend.worker.gmail_client import GmailClient

app = FastAPI(title="PDF Trainer API", version="1.0")

# Allow Vite dev server
app.add_middleware(
    CORSMiddleware,
    allow_origins=[
        "http://localhost:5173",
        "http://127.0.0.1:5173",
    ],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

REPO_ROOT = Path(__file__).resolve().parents[1]
BACKEND_DIR = REPO_ROOT / "backend"
UPLOADS_DIR = BACKEND_DIR / "worker" / "uploads"

# Load backend/.env explicitly ONCE for this process
load_dotenv(BACKEND_DIR / ".env", override=True)

CREDENTIALS_JSON = Path(os.environ.get("GMAIL_CREDENTIALS_JSON", str(BACKEND_DIR / "credentials.json")))
TOKEN_JSON = Path(os.environ.get("GMAIL_TOKEN_JSON", str(BACKEND_DIR / "token.json")))


def _gmail() -> GmailClient:
    return GmailClient(CREDENTIALS_JSON, TOKEN_JSON)


def _get_env_required(key: str) -> str:
    v = (os.environ.get(key) or "").strip()
    if not v:
        raise HTTPException(status_code=500, detail=f"Server missing {key} env var")
    return v


@app.get("/health")
def health():
    return {"ok": True}


@app.get("/api/pdf/{pdf_id}")
def get_pdf(pdf_id: str):
    path = UPLOADS_DIR / f"{pdf_id}.pdf"
    if not path.exists():
        raise HTTPException(status_code=404, detail="PDF not found")

    name_path = UPLOADS_DIR / f"{pdf_id}.name.txt"
    pdf_name = name_path.read_text(encoding="utf-8").strip() if name_path.exists() else f"{pdf_id}.pdf"

    resp = FileResponse(path, media_type="application/pdf", filename=pdf_name)
    resp.headers["X-PDF-Name"] = pdf_name
    return resp


@app.post("/api/send-config")
async def send_config(payload: Dict[str, Any]):
    """
    PIPELINE SUBMISSION EMAIL (after rep saves config)

    REQUIRED payload:
      - pdf_id: str
      - template_id: str
      - config: dict

    Sends to PIPELINE inbox:
      - PDF_PIPELINE_PIPELINE_NOTIFY_TO

    Requirements:
      - Subject includes template_id
      - Body includes pdf_id
      - Attachments: JSON + PDF
    """
    pdf_id = (payload.get("pdf_id") or "").strip()
    template_id = (payload.get("template_id") or "").strip()
    config = payload.get("config")

    if not pdf_id:
        raise HTTPException(status_code=400, detail="Missing pdf_id")
    if not template_id:
        raise HTTPException(status_code=400, detail="Missing template_id")
    if not isinstance(config, dict):
        raise HTTPException(status_code=400, detail="Missing config object")

    pipeline_to = _get_env_required("PDF_PIPELINE_PIPELINE_NOTIFY_TO")
    notify_from = _get_env_required("PDF_PIPELINE_NOTIFY_FROM")
    trainer_base_url = (os.environ.get("PDF_TRAINER_BASE_URL") or "http://localhost:5173").strip()

    pdf_path = UPLOADS_DIR / f"{pdf_id}.pdf"
    if not pdf_path.exists():
        raise HTTPException(status_code=404, detail="PDF not found for pdf_id")

    name_path = UPLOADS_DIR / f"{pdf_id}.name.txt"
    pdf_name = name_path.read_text(encoding="utf-8").strip() if name_path.exists() else f"{pdf_id}.pdf"

    trainer_link = f"{trainer_base_url.rstrip('/')}/?pdf_id={pdf_id}"

    subject = f"PDF_TRAINER_CONFIG_SUBMITTED | template_id={template_id}"
    body = (
        "Hi,\n\n"
        "A PDF Trainer configuration was submitted.\n\n"
        f"template_id: {template_id}\n"
        f"pdf_id: {pdf_id}\n"
        f"trainer_link: {trainer_link}\n\n"
        "Attachments:\n"
        f"- trainer_config_{pdf_id}_{template_id}.json\n"
        f"- {pdf_name}\n\n"
        "Thank you,\n"
        "Inserio Automation\n"
    )

    cfg_bytes = json.dumps(
        {"pdf_id": pdf_id, "template_id": template_id, "config": config},
        indent=2,
    ).encode("utf-8")

    attachments = [
        (f"trainer_config_{pdf_id}_{template_id}.json", cfg_bytes),
        (pdf_name, pdf_path.read_bytes()),
    ]

    gmail = _gmail()
    gmail.send_email(
        to_email=pipeline_to,
        from_email=notify_from,
        subject=subject,
        body_text=body,
        attachments=attachments,
    )

    return {"ok": True}


@app.post("/api/notify-unknown")
async def notify_unknown(payload: Dict[str, Any]):
    """
    UNKNOWN TEMPLATE NOTIFICATION (rep email)

    REQUIRED payload:
      - pdf_id: str
    OPTIONAL:
      - reason: str

    Sends to REP inbox:
      - PDF_PIPELINE_NOTIFY_TO

    Requirements:
      - Includes trainer link with PDF pre-loaded
      - Attaches PDF
      - No JSON
    """
    pdf_id = (payload.get("pdf_id") or "").strip()
    reason = (payload.get("reason") or "").strip()

    if not pdf_id:
        raise HTTPException(status_code=400, detail="Missing pdf_id")

    rep_to = _get_env_required("PDF_PIPELINE_NOTIFY_TO")
    notify_from = _get_env_required("PDF_PIPELINE_NOTIFY_FROM")
    trainer_base_url = (os.environ.get("PDF_TRAINER_BASE_URL") or "http://localhost:5173").strip()

    pdf_path = UPLOADS_DIR / f"{pdf_id}.pdf"
    if not pdf_path.exists():
        raise HTTPException(status_code=404, detail="PDF not found for pdf_id")

    name_path = UPLOADS_DIR / f"{pdf_id}.name.txt"
    pdf_name = name_path.read_text(encoding="utf-8").strip() if name_path.exists() else f"{pdf_id}.pdf"

    trainer_link = f"{trainer_base_url.rstrip('/')}/?pdf_id={pdf_id}"

    subject = "Action required: Unknown PDF format (template not found)"
    body = (
        "Hi,\n\n"
        "We received a PDF that does not match any existing templates in the system.\n\n"
        + (f"Reason: {reason}\n\n" if reason else "")
        + "Please open the PDF Trainer using the link below and create or update the template configuration:\n"
        f"{trainer_link}\n\n"
        "The original PDF is attached for reference.\n\n"
        "Thank you,\n"
        "Inserio Automation\n"
    )

    attachments = [(pdf_name, pdf_path.read_bytes())]

    gmail = _gmail()
    gmail.send_email(
        to_email=rep_to,
        from_email=notify_from,
        subject=subject,
        body_text=body,
        attachments=attachments,
    )

    return {"ok": True}


@app.get("/", response_class=PlainTextResponse)
def root():
    return "PDF Trainer API. Use /health"