import os
from fastapi import FastAPI, HTTPException, Header, UploadFile, File
from fastapi.middleware.cors import CORSMiddleware
import gradio as gr
from typhoon_ocr import ocr_document
from pdf2image import convert_from_bytes
from PIL import Image
import re
from dotenv import load_dotenv

# --- Load environment variables from .env ---
load_dotenv()

# --- Config ---
API_KEY = os.getenv("API_KEY")
TYPHOON_API_KEY = os.getenv("TYPHOON_OCR_API_KEY")
TYPHOON_BASE_URL = os.getenv("TYPHOON_BASE_URL", "https://api.opentyphoon.ai/v1")

# --- FastAPI App ---
app = FastAPI()

# CORS (optional for public usage)
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_methods=["*"],
    allow_headers=["*"],
)

def extract_fields_regex(text: str) -> dict:
    # Preprocess text
    text = re.sub(r"<.*?>", "", text)  # Strip tags
    text = re.sub(r"\n+", "\n", text)  # Collapse newlines
    text = re.sub(r"\s{2,}", " ", text)  # Collapse multiple spaces
    text = re.sub(r"\t+", " ", text)

    patterns = {
        "tax_id": r"(?:TAX\s*ID|เลขที่ผู้เสียภาษี)[\s:\-\.]*([\d]{10,13})",
        "tax_invoice": r"(?:TAX\s*INV\.?|เลขที่ใบกำกับภาษี|ใบกำกับ)[\s:\-\.]*([\dA-Z\-\/]{6,20})",
        "tax_date": r"(?:DATE|วันที่|ออกใบกำกับวันที่)?[\s:\-\.]*([\d]{2,4}/[\d]{1,2}/[\d]{1,2})",
        "amount": r"(?:AMOUNT\s*THB|จำนวนเงิน|รวมเงิน)[\s:\-\.]*([\d,]+\.\d{2})",
        "baht_per_litre": r"(?:Baht\/Litr\.?|Bath\/Ltr\.?|ราคาต่อลิตร|ราคา\/ลิตร|ราคาน้ำมัน|บาทต่อลิตร)[\s:\-\.]*([\d,]+\.\d{2})",
        "litre": r"(?:Ltr\.?|Ltrs?\.?|ลิตร)[\s:\-\.]*([\d,]+\.\d{2,3})",
        "vat": r"(?:VAT|ภาษีมูลค่าเพิ่ม)[\s:\-\.]*([\d,]+\.\d{2})",
        "total": r"(?:TOTAL\s*THB|ยอดรวม|รวมทั้งสิ้น|รวมเงินทั้งสิ้น|ยอดเงินสุทธิ)[\s:\-\.]*([\d,]+\.\d{2})",
    }

    results = {}
    for field, pattern in patterns.items():
        match = re.search(pattern, text, re.IGNORECASE)
        results[field] = match.group(1).strip() if match else None

    # Optional fallback if regex fails
    # if not results["เลขที่ใบกำกับภาษี"]:
    #     match = re.search(r"TAX\s*INV\.?\s*</td>\s*<td>\s*([\d\-]+)", text, re.IGNORECASE)
    # if match:
    #     results["เลขที่ใบกำกับภาษี"] = match.group(1).strip()

    return results


def pdf_to_image(file_bytes: bytes) -> Image.Image:
    images = convert_from_bytes(file_bytes)
    return images[0]  # First page only


# --- API Endpoint ---
@app.post("/api/ocr_receipt")
async def ocr_receipt(
    file: UploadFile = File(...),
    x_api_key: str | None = Header(None),
):
    if API_KEY and x_api_key != API_KEY:
        raise HTTPException(status_code=401, detail="Invalid API key")

    content = await file.read()

    try:
        # Handle PDF and image
        if file.filename.lower().endswith(".pdf"):
            image = pdf_to_image(content)
            raw_output = ocr_document(image, task_type="structure")
        else:
            raw_output = ocr_document(content, task_type="structure")

        text = raw_output if isinstance(raw_output, str) else raw_output.get("text", "")
        extracted = extract_fields_regex(text)

        return {
            "raw_ocr": text,
            "extracted_fields": extracted,
        }

    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))


# --- Gradio UI ---
def gradio_interface(image_path: str | Image.Image):
    if isinstance(image_path, str) and image_path.lower().endswith(".pdf"):
        with open(image_path, "rb") as f:
            image = pdf_to_image(f.read())
    else:
        image = image_path

    raw = ocr_document(image, task_type="structure")
    text = raw if isinstance(raw, str) else raw.get("text", "")
    extracted = extract_fields_regex(text)
    return text, extracted


with gr.Blocks() as demo:
    gr.Markdown("# 🧾 แปลงและตรวจสอบใบเสร็จ")
    with gr.Row():
        img = gr.Image(type="filepath", label="อัปโหลดไฟล์ PDF หรือรูปภาพ")
        out_text = gr.Textbox(label="ข้อความทั้งหมด", lines=10)
        out_fields = gr.JSON(label="ข้อความที่ดึงออกมา")
    btn = gr.Button("ประมวลผลใบเสร็จ")
    btn.click(fn=gradio_interface, inputs=img, outputs=[out_text, out_fields])

# --- Mount Gradio on FastAPI ---
# app = gr.mount_gradio_app(app, demo, path="/ui")
demo.launch(share=False)