import os
import re
import tempfile
from pathlib import Path

import gradio as gr
import pandas as pd
from pypdf import PdfReader

from parsers.systemax import parse as parse_systemax
from parsers.home_depot import parse as parse_home_depot
from parsers.staples_com import parse as parse_staples_com
from parsers.staples_advantage import parse as parse_staples_advantage
from parsers.walmart import parse as parse_walmart
from parsers.lowes import parse as parse_lowes
from parsers.quill import parse as parse_quill
from parsers.msc_industrial import parse as parse_msc_industrial
from parsers.lowes_rona import parse as parse_lowes_rona
from parsers.united_stationers import parse as parse_united_stationers
from parsers.bh_photo_video import parse as parse_bh_photo_video

HEADERS = ["Trading Partner", "PO Number", "Ship Via", "Order Date", "Source PDF"]

def normalize(text):
    text = text.replace("\x00", " ")
    text = text.replace("\r", "\n")
    text = re.sub(r"[ \t]+", " ", text)
    text = re.sub(r"\n[ \t]+", "\n", text)
    text = re.sub(r"\n{3,}", "\n\n", text)
    return text.strip()

def read_pdf(path):
    reader = PdfReader(path)
    pages = []
    for page in reader.pages:
        try:
            pages.append(page.extract_text() or "")
        except Exception:
            pages.append("")
    return "\n\n".join(pages)

def identify_vendor(filename):
    n = re.sub(r"[^a-z0-9]", "", Path(filename).stem.lower())

    # More specific names must be checked before generic substrings
    # (e.g. "lowesrona" before "lowes").
    if "systemax" in n:
        return "SYSTEMAX"
    if "homedepot" in n:
        return "HOME DEPOT"
    if "staplesadvantage" in n:
        return "STAPLES ADVANTAGE"
    if "staplescom" in n:
        return "STAPLES.COM"
    if "walmartcomdirecttocustomer" in n or "walmart" in n:
        return "WALMART"
    if "lowesrona" in n or "ronaps" in n or ("rona" in n and "lowes" in n):
        return "LOWE'S / RONA"
    if "lowessos" in n or "lowes" in n:
        return "LOWE'S"
    if "quillcom" in n or "quill" in n:
        return "QUILL"
    if "mscindustrial" in n or n.startswith("msc"):
        return "MSC INDUSTRIAL SUPPLY"
    if "unitedstationers" in n or "essendant" in n:
        return "UNITED STATIONERS"
    if "bandhphotovideo" in n or "bhphotovideo" in n:
        return "B&H PHOTO-VIDEO"

    return "UNKNOWN"

PARSERS = {
    "SYSTEMAX": parse_systemax,
    "HOME DEPOT": parse_home_depot,
    "STAPLES.COM": parse_staples_com,
    "STAPLES ADVANTAGE": parse_staples_advantage,
    "WALMART": parse_walmart,
    "LOWE'S": parse_lowes,
    "QUILL": parse_quill,
    "MSC INDUSTRIAL SUPPLY": parse_msc_industrial,
    "LOWE'S / RONA": parse_lowes_rona,
    "UNITED STATIONERS": parse_united_stationers,
    "B&H PHOTO-VIDEO": parse_bh_photo_video,
}

def process_one(path):
    filename = Path(path).name
    vendor = identify_vendor(filename)

    if vendor == "UNKNOWN":
        return [], f"⚠️ UNKNOWN VENDOR: {filename}"

    raw = read_pdf(path)
    text = normalize(raw)

    if not text:
        return [], f"⚠️ NO TEXT EXTRACTED: {filename}"

    rows = PARSERS[vendor](text)

    clean = []
    for row in rows:
        row = {
            "Trading Partner": vendor,
            "PO Number": str(row.get("PO Number", "")).strip(),
            "Ship Via": str(row.get("Ship Via", "")).strip(),
            "Order Date": str(row.get("Order Date", "")).strip(),
            "Source PDF": filename,
        }

        # Never allow obvious non-PO text into the PO column.
        po = row["PO Number"]
        if po and (
            len(po) > 40
            or "direct inquiries" in po.lower()
            or "customer service" in po.lower()
            or po.lower() in {
                "services", "service", "customer", "sales", "date",
                "location", "salesperson", "release", "order",
            }
        ):
            row["PO Number"] = ""

        # Reject dates mistakenly captured as Ship Via.
        ship = row["Ship Via"]
        if ship and re.fullmatch(r"\d{1,2}/\d{1,2}/\d{2,4}", ship):
            if not row["Order Date"]:
                row["Order Date"] = ship
            row["Ship Via"] = ""

        if any(row[h] for h in HEADERS[:-1]):
            clean.append(row)

    return clean, f"✅ {vendor}: {len(clean)} record(s)"

def process_files(files):
    if not files:
        return "Please upload one or more PDF files.", None

    all_rows = []
    messages = []

    for f in files:
        path = getattr(f, "name", f)
        try:
            rows, message = process_one(path)
            all_rows.extend(rows)
            messages.append(message)
        except Exception as e:
            messages.append(f"❌ {Path(path).name}: {type(e).__name__}: {e}")

    df = pd.DataFrame(all_rows, columns=HEADERS)

    # Keep leading zeros by storing PO values as strings.
    if not df.empty:
        df["PO Number"] = df["PO Number"].astype(str)

    tmp = tempfile.NamedTemporaryFile(delete=False, suffix=".xlsx")
    tmp.close()
    df.to_excel(tmp.name, index=False, engine="openpyxl")

    summary = "\n".join(messages)
    summary += f"\n\nTOTAL RECORDS: {len(df)}"

    return summary, tmp.name

THEME = gr.themes.Soft(
    primary_hue="rose",
    secondary_hue="teal",
    neutral_hue="stone",
    font=[gr.themes.GoogleFont("Nunito"), "ui-sans-serif", "system-ui", "sans-serif"],
    font_mono=[gr.themes.GoogleFont("IBM Plex Mono"), "ui-monospace", "monospace"],
).set(
    body_background_fill="#f7f3ef",
    body_background_fill_dark="#f7f3ef",
    block_background_fill="#ffffff",
    block_border_width="0px",
    block_radius="18px",
    block_shadow="0 8px 28px rgba(120, 90, 90, 0.08)",
    button_primary_background_fill="#e86b7a",
    button_primary_background_fill_hover="#d95a6a",
    button_primary_text_color="#ffffff",
    button_large_radius="14px",
    input_radius="14px",
)

APP_CSS = """
@import url('https://fonts.googleapis.com/css2?family=Nunito:wght@500;600;700;800&display=swap');

.gradio-container {
  max-width: 1100px !important;
  margin: 0 auto !important;
  padding: 0.85rem 1rem 1rem !important;
  font-family: 'Nunito', ui-sans-serif, system-ui, sans-serif !important;
}

.main-wrap {
  display: flex;
  flex-direction: column;
  gap: 0.7rem !important;
}

.hero-card {
  background: linear-gradient(135deg, #fff7f5 0%, #ffffff 55%, #f3fbf8 100%);
  border: 1px solid rgba(232, 107, 122, 0.18);
  border-radius: 18px;
  padding: 0.75rem 1.1rem !important;
  box-shadow: 0 10px 30px rgba(180, 110, 110, 0.08);
}

.hero-card h1 {
  font-size: 1.4rem !important;
  font-weight: 800 !important;
  letter-spacing: -0.02em;
  color: #3d2c2e !important;
  margin: 0 !important;
}

.hero-card p {
  display: none !important;
}

.panel {
  background: #ffffff;
  border-radius: 16px;
  padding: 0.65rem 0.75rem 0.55rem !important;
  box-shadow: 0 8px 24px rgba(120, 90, 90, 0.07);
  border: 1px solid rgba(80, 60, 60, 0.05);
}

.panel .label-wrap span,
.panel label span {
  font-weight: 700 !important;
  color: #5c4548 !important;
}

button.primary,
.primary {
  min-height: 42px !important;
  font-weight: 800 !important;
  letter-spacing: 0.02em !important;
  box-shadow: 0 8px 18px rgba(232, 107, 122, 0.28) !important;
}

/* Force true 50/50 side-by-side layout */
#main-split {
  display: grid !important;
  grid-template-columns: 1fr 1fr !important;
  gap: 0.75rem !important;
  align-items: stretch !important;
}

#main-split > div {
  min-width: 0 !important;
  width: 100% !important;
  max-width: none !important;
  flex: unset !important;
}

#upload-col {
  height: 100% !important;
}

#upload-col .wrap,
#upload-col [data-testid="file"] {
  height: 100% !important;
}

#upload-col .file-preview-holder,
#upload-col .file-preview,
#upload-col ul,
#upload-col .scroll-hide {
  max-height: 260px !important;
  overflow-y: auto !important;
}

#side-col {
  display: flex !important;
  flex-direction: column !important;
  gap: 0.7rem !important;
  height: 100% !important;
  min-height: 340px !important;
}

#side-col > div {
  flex: 1 1 0 !important;
  min-height: 160px !important;
}

#status-box textarea {
  min-height: 140px !important;
  height: 140px !important;
  max-height: 180px !important;
  overflow-y: auto !important;
  resize: none !important;
}

#download-box,
#download-box .wrap,
#download-box [data-testid="file"] {
  min-height: 140px !important;
  height: 140px !important;
}

@media (max-width: 760px) {
  #main-split {
    grid-template-columns: 1fr !important;
  }
}

footer { display: none !important; }
"""

with gr.Blocks(title="Packing List PDF Extractor") as demo:
    with gr.Column(elem_classes=["main-wrap"]):
        gr.Markdown("# Packing List PDF Extractor", elem_classes=["hero-card"])
        process = gr.Button("Process PDFs", variant="primary", size="lg")

        with gr.Row(elem_id="main-split"):
            with gr.Column(elem_id="upload-col", elem_classes=["panel"]):
                files = gr.File(
                    label="Upload PDFs",
                    file_count="multiple",
                    file_types=[".pdf"],
                    type="filepath",
                    height=340,
                )
            with gr.Column(elem_id="side-col"):
                with gr.Column(elem_classes=["panel"]):
                    status = gr.Textbox(
                        label="Status",
                        lines=7,
                        max_lines=9,
                        elem_id="status-box",
                    )
                with gr.Column(elem_classes=["panel"]):
                    download = gr.File(
                        label="Excel download",
                        height=140,
                        elem_id="download-box",
                    )

        clear = gr.Button("Clear form", variant="secondary", size="lg")

    def clear_form():
        return None, "", None

    process.click(
        fn=process_files,
        inputs=files,
        outputs=[status, download],
    )
    clear.click(
        fn=clear_form,
        inputs=None,
        outputs=[files, status, download],
    )

if __name__ == "__main__":
    # HF Spaces needs 0.0.0.0; locally bind to localhost so the URL is usable.
    on_spaces = bool(os.getenv("SPACE_ID") or os.getenv("SYSTEM") == "spaces")
    demo.launch(
        server_name="0.0.0.0" if on_spaces else "127.0.0.1",
        server_port=7860,
        ssr_mode=False,
        theme=THEME,
        css=APP_CSS,
    )