"""Assemble all generated report sections into a professional RICS Level 3 DOCX.

The builder takes a ``dict[section_code, SectionPayload]`` and produces a
ready-to-download ``.docx`` file matching the canonical RICS Level 3 Building
Survey structure (sections A → B → C → D → E1–E9 → F1–F9 → G1–G8 →
H1–H3 → I1–I3 → J1–J4 → K1–K5 → L).

Features:
* Branded title page (report title, generated date, disclaimer).
* Group headings matching official RICS wording (e.g. "E — Outside the
  property") rendered as Heading 1.
* Element sub-headings (e.g. "E2  Roof coverings") as Heading 2.
* Condition Rating badge printed after each element with a rating.
* Legacy ``[VERIFY: …]`` markers are sanitised during export (the reconstruction pipeline does not emit them).
* Editor notes (from proofread mode) in an indented italic callout.
* Professional footer on every page: RICS disclaimer + reviewer signature.
* Per-section **estimated AI involvement** (when metadata is present) and
  **source references** (filename, relevance, heading hint, snippet preview)
  for traceability to tenant uploads.

No external dependencies beyond ``python-docx`` (already in ``pyproject.toml``).
"""

from __future__ import annotations

import io
import re
from datetime import UTC, datetime
from typing import TYPE_CHECKING, Any

from docx import Document
from docx.document import Document as DocxDocument
from docx.enum.text import WD_ALIGN_PARAGRAPH, WD_COLOR_INDEX
from docx.oxml import OxmlElement
from docx.oxml.ns import qn
from docx.shared import Inches, Pt, RGBColor
from docx.text.run import Run

from app.templates.registry import get_survey_pack, get_template

if TYPE_CHECKING:
    from app.models.schemas import SectionPayload

# Regex to find legacy [VERIFY: …] or [VERIFY] tags
_VERIFY_RE = re.compile(r"(\[VERIFY[^\]]*\])")

_DISCLAIMER = (
    "IMPORTANT NOTICE: This report has been generated with AI assistance and must be "
    "reviewed, verified, and approved by a qualified RICS surveyor before use. "
    "Items marked as missing/unverifiable require human confirmation. Nothing herein constitutes "
    "professional surveying advice without a surveyor's written sign-off."
)


def build_docx(
    sections: dict[str, SectionPayload],
    report_id: str,
    tenant_id: str,
    survey_level: int | None = None,
    section_photo_paths: dict[str, list[str]] | None = None,
    write_audit: bool = True,
) -> bytes:
    """Assemble a professional RICS Home Survey DOCX for the report's product tier.

    Section order, group headings, and the title page use the template pack for
    ``survey_level`` (1 = Condition Report, 2 = HomeBuyer / L2, 3 = Building Survey).
    When ``survey_level`` is omitted, Level 3 is used (legacy).

    Args:
        sections: Mapping of ``section_code → SectionPayload`` from the API.
        report_id: UUID of the report (shown on the title page).
        tenant_id: Tenant identifier (shown on the title page).
        survey_level: RICS product tier (1/2/3) from ``Report.survey_level``.

    Returns:
        Raw ``.docx`` bytes ready to serve as a file download.

    Example::

        raw = build_docx(sections=data["sections"], report_id="...", tenant_id="...", survey_level=1)
        return Response(content=raw, media_type="application/.../wordprocessingml.document")
    """
    pack = get_survey_pack(survey_level)
    doc = Document()

    # Post-generation audit (non-destructive): true AI-involvement average,
    # high-involvement sections, and misplaced-content flags. Computed from the
    # section payloads themselves so the cover page reflects ACTUAL behaviour
    # rather than the requested slider value.
    from app.generator.report_audit import (
        aggregate_ai_involvement,
        detect_misplaced_content,
        write_audit_log,
    )

    _per_section_pct: dict[str, int | None] = {}
    _section_texts: dict[str, str] = {}
    for _code, _pl in sections.items():
        _trx = getattr(_pl, "ai_transparency", None)
        _per_section_pct[_code] = (
            _trx.get("ai_involvement_percent") if isinstance(_trx, dict) else None
        )
        _section_texts[_code] = getattr(_pl, "text", "") or ""
    _involvement = aggregate_ai_involvement(_per_section_pct)
    _misplaced = detect_misplaced_content(_section_texts)

    _apply_global_styles(doc)
    _add_page_footer(doc)
    _add_title_page(
        doc,
        report_id,
        tenant_id,
        docx_title=pack.docx_title,
        product_label=pack.product_label,
        level=pack.level,
    )
    _add_report_audit_summary(doc, _involvement, _misplaced)

    # Reconstruction output must not include placeholder tokens (e.g. [VERIFY]).
    # Legacy tokens are sanitised per-section; we do not add any "[VERIFY]" legend page.
    has_verify = False
    current_group: str | None = None

    for code in pack.section_order:
        tmpl = get_template(code, survey_level)
        if tmpl is None:
            continue

        # Insert a group-level heading whenever the group changes
        if tmpl.group != current_group:
            current_group = tmpl.group
            group_label = pack.group_labels.get(current_group, current_group)
            h1 = doc.add_heading(group_label, level=1)
            h1.paragraph_format.space_before = Pt(18)
            h1.paragraph_format.space_after = Pt(6)

        payload = sections.get(code)
        _add_section(
            doc,
            code,
            tmpl.title,
            payload,
            tmpl.has_condition_rating,
            photo_paths=(section_photo_paths or {}).get(code, []),
        )

        # No verify-token detection (sanitised per-section).

    # No verify legend in reconstruction mode.

    if write_audit:
        write_audit_log(
            report_id,
            involvement=_involvement,
            misplacement_flags=_misplaced,
        )

    buf = io.BytesIO()
    doc.save(buf)
    return buf.getvalue()


def _add_report_audit_summary(doc: DocxDocument, involvement: Any, misplaced: list[Any]) -> None:
    """Cover-page audit block: true average AI involvement + quality flags."""
    p = doc.add_paragraph()
    r = p.add_run(f"Average AI involvement across generated sections: {involvement.average_percent}%")
    r.font.bold = True
    r.font.size = Pt(10)
    r.font.color.rgb = RGBColor(0x1B, 0x3A, 0x5C)
    p.paragraph_format.space_before = Pt(6)

    if involvement.high_sections:
        names = ", ".join(f"{c} ({v}%)" for c, v in involvement.high_sections)
        pw = doc.add_paragraph()
        rw = pw.add_run(
            "\u26a0 High-AI-involvement sections requiring scrutiny before "
            f"sign-off: {names}."
        )
        rw.font.bold = True
        rw.font.size = Pt(9)
        rw.font.color.rgb = RGBColor(0xB0, 0x3A, 0x2E)

    if misplaced:
        ph = doc.add_paragraph()
        rh = ph.add_run("Content placement flags (review — not auto-moved):")
        rh.font.bold = True
        rh.font.size = Pt(9)
        rh.font.color.rgb = RGBColor(0xB0, 0x3A, 0x2E)
        for f in misplaced[:20]:
            pf = doc.add_paragraph()
            pf.paragraph_format.left_indent = Inches(0.15)
            rf = pf.add_run(
                f"\u2022 {f.topic} found in {f.section_code} \u2014 likely belongs "
                f"in {f.suggested_section}: \u201c{f.excerpt}\u201d"
            )
            rf.font.size = Pt(8.5)
            rf.font.color.rgb = RGBColor(0x55, 0x66, 0x77)


# ── Document-level styling ────────────────────────────────────────────────────

def _apply_global_styles(doc: DocxDocument) -> None:
    """Set default font, margins, and paragraph spacing."""
    section = doc.sections[0]
    section.top_margin = Inches(1.1)
    section.bottom_margin = Inches(1.1)
    section.left_margin = Inches(1.25)
    section.right_margin = Inches(1.25)

    style = doc.styles["Normal"]
    font = style.font
    font.name = "Calibri"
    font.size = Pt(11)
    font.color.rgb = RGBColor(0x1A, 0x23, 0x32)

    for level, size, bold in [(1, 14, True), (2, 12, True), (3, 11, True)]:
        name = f"Heading {level}"
        if name in doc.styles:
            h = doc.styles[name]
            h.font.name = "Calibri"
            h.font.size = Pt(size)
            h.font.bold = bold
            h.font.color.rgb = RGBColor(0x1B, 0x3A, 0x5C)  # RICS navy


def _add_page_footer(doc: DocxDocument) -> None:
    """Add footer: RICS disclaimer on the left, reviewer signature on a second line."""
    section = doc.sections[0]
    footer = section.footer
    footer.is_linked_to_previous = False

    p1 = footer.paragraphs[0]
    p1.clear()
    r = p1.add_run(_DISCLAIMER)
    r.font.size = Pt(7.5)
    r.font.italic = True
    r.font.color.rgb = RGBColor(0x80, 0x80, 0x80)

    p2 = footer.add_paragraph()
    r2 = p2.add_run(
        "Reviewed and approved by (RICS surveyor): ________________________    "
        "Date: ________________"
    )
    r2.font.size = Pt(9)
    r2.font.bold = True
    r2.font.color.rgb = RGBColor(0x1B, 0x3A, 0x5C)


# ── Title page ────────────────────────────────────────────────────────────────

def _add_title_page(
    doc: DocxDocument,
    report_id: str,
    tenant_id: str,
    *,
    docx_title: str,
    product_label: str,
    level: int,
) -> None:
    """Insert a branded title page."""
    for _ in range(4):
        doc.add_paragraph()

    p_title = doc.add_paragraph()
    p_title.alignment = WD_ALIGN_PARAGRAPH.CENTER
    run = p_title.add_run(docx_title.strip() or "RICS Home Survey Report")
    run.font.name = "Calibri"
    run.font.size = Pt(22)
    run.font.bold = True
    run.font.color.rgb = RGBColor(0x1B, 0x3A, 0x5C)

    p_sub = doc.add_paragraph()
    p_sub.alignment = WD_ALIGN_PARAGRAPH.CENTER
    sub = p_sub.add_run("AI-Assisted Draft — For Professional Review and Sign-Off")
    sub.font.name = "Calibri"
    sub.font.size = Pt(13)
    sub.font.italic = True
    sub.font.color.rgb = RGBColor(0xC8, 0xA0, 0x20)  # gold

    doc.add_paragraph()
    doc.add_paragraph()

    p_lvl = doc.add_paragraph()
    p_lvl.alignment = WD_ALIGN_PARAGRAPH.CENTER
    r_lvl = p_lvl.add_run(f"Survey level: Level {int(level)} — {product_label}")
    r_lvl.font.name = "Calibri"
    r_lvl.font.size = Pt(11)
    r_lvl.font.bold = True
    r_lvl.font.color.rgb = RGBColor(0x1B, 0x3A, 0x5C)

    generated_at = datetime.now(UTC).strftime("%d %B %Y at %H:%M UTC")
    for label, value in [
        ("Generated", generated_at),
        ("Report ID", report_id),
        ("Surveying Firm / Tenant", tenant_id),
        ("Status", "DRAFT — Requires RICS surveyor review before release to client"),
    ]:
        p = doc.add_paragraph()
        p.alignment = WD_ALIGN_PARAGRAPH.CENTER
        rl = p.add_run(f"{label}:  ")
        rl.font.bold = True
        rl.font.size = Pt(11)
        rl.font.color.rgb = RGBColor(0x1B, 0x3A, 0x5C)
        rv = p.add_run(value)
        rv.font.size = Pt(11)
        if label == "Status":
            rv.font.color.rgb = RGBColor(0xC0, 0x39, 0x2B)  # red

    doc.add_page_break()  # type: ignore[no-untyped-call]


# ── Section rendering ─────────────────────────────────────────────────────────

def _add_section(
    doc: DocxDocument,
    code: str,
    title: str,
    payload: SectionPayload | None,
    has_condition_rating: bool,
    photo_paths: list[str] | None = None,
) -> None:
    """Render one section element as Heading 2 + body."""
    heading = doc.add_heading(f"{code}  {title}", level=2)
    heading.paragraph_format.space_before = Pt(12)
    heading.paragraph_format.space_after = Pt(4)

    if payload is None:
        p = doc.add_paragraph()
        r = p.add_run("[Section not yet generated — to be completed by the surveyor]")
        r.font.italic = True
        r.font.color.rgb = RGBColor(0x90, 0x90, 0x90)
        return

    # Photo evidence (uploaded by the user)
    paths = [p for p in (photo_paths or []) if p]
    if paths:
        cap = doc.add_paragraph()
        cap_r = cap.add_run("Photo evidence (uploaded)")
        cap_r.font.bold = True
        cap_r.font.size = Pt(9.5)
        cap_r.font.color.rgb = RGBColor(0x1B, 0x3A, 0x5C)
        cap.paragraph_format.space_after = Pt(4)
        for p in paths[:8]:
            try:
                doc.add_picture(p, width=Inches(5.8))
            except Exception:
                # Never break export for a missing/corrupt image; continue.
                continue
        doc.add_paragraph().paragraph_format.space_after = Pt(6)

    # Strip editor notes appended by proofread mode
    body_text = payload.text

    # Legacy placeholder clean-up: the reconstruction pipeline must not emit [VERIFY] tokens.
    # If older cached content or manual edits include them, replace with an approved phrase.
    if _VERIFY_RE.search(body_text):
        body_text = _VERIFY_RE.sub("Information not provided in source document.", body_text)
    editor_notes: str | None = None
    if "[Editor notes:" in body_text:
        idx = body_text.index("[Editor notes:")
        editor_notes = body_text[idx:].removeprefix("[Editor notes:").removesuffix("]").strip()
        body_text = body_text[:idx].strip()

    # Detect and render inline condition rating (e.g. "Condition Rating 3")
    condition_badge, body_text = _extract_condition_rating(body_text, has_condition_rating)

    # Body text (no placeholder highlighting in reconstruction mode)
    _add_text_with_verify_highlights(doc, body_text)

    # Condition rating badge
    if condition_badge:
        cr_p = doc.add_paragraph()
        cr_run = cr_p.add_run(f"  Condition Rating: {condition_badge}  ")
        cr_run.font.bold = True
        cr_run.font.size = Pt(10)
        color = {
            "3": RGBColor(0xC0, 0x39, 0x2B),   # red — urgent
            "2": RGBColor(0xC8, 0x6E, 0x00),   # amber — attention needed
            "1": RGBColor(0x1A, 0x7F, 0x4B),   # green — satisfactory
            "NI": RGBColor(0x60, 0x70, 0x80),  # grey — not inspected
        }.get(condition_badge, RGBColor(0x1A, 0x23, 0x32))
        cr_run.font.color.rgb = color
        cr_p.paragraph_format.space_after = Pt(4)

    # Mode + confidence metadata line
    mode_map = {"generate": "✍ Generated", "proofread": "📝 Proofread", "enhance": "⚙ Enhanced"}
    mode_label = mode_map.get(payload.mode, payload.mode.title())
    conf_pct = round(payload.confidence * 100)
    meta_p = doc.add_paragraph()
    meta_r = meta_p.add_run(
        f"{mode_label}  ·  Confidence {conf_pct}%"
        + ("  ·  ⚡ Cached" if payload.cached else "")
    )
    meta_r.font.size = Pt(8.5)
    meta_r.font.color.rgb = RGBColor(0x6A, 0x7A, 0x8A)
    meta_r.font.italic = True
    meta_p.paragraph_format.space_after = Pt(6)

    _add_transparency_and_sources(doc, payload)

    if editor_notes:
        _add_editor_notes(doc, editor_notes)


def _extract_condition_rating(text: str, has_condition_rating: bool) -> tuple[str, str]:
    """Pull the final Condition Rating out of the text and return (badge, cleaned_text).

    Args:
        text: Section body text, possibly ending with "Condition Rating 2."
        has_condition_rating: Whether this section type carries a rating.

    Returns:
        ``(badge_string, cleaned_text)`` where badge_string is ``"1"``, ``"2"``,
        ``"3"``, ``"NI"`` or ``""`` if not found/applicable.
    """
    if not has_condition_rating:
        return "", text

    # Match "Condition Rating 3", "Condition Rating NI" at end of text
    pattern = re.compile(
        r"[\.\s]*Condition\s+Rating[:\s]+([123]|NI)[\.\s]*$", re.IGNORECASE
    )
    m = pattern.search(text)
    if m:
        badge = m.group(1).upper()
        cleaned = text[: m.start()].rstrip()
        return badge, cleaned
    return "", text


def _add_text_with_verify_highlights(doc: DocxDocument, text: str) -> None:
    """Write text as a Normal paragraph (legacy [VERIFY] spans are already sanitised)."""
    p = doc.add_paragraph()
    p.style = doc.styles["Normal"]
    p.paragraph_format.space_after = Pt(6)
    parts = _VERIFY_RE.split(text)
    for part in parts:
        if not part:
            continue
        run = p.add_run(part)
        if _VERIFY_RE.match(part):
            run.font.bold = True
            run.font.color.rgb = RGBColor(0xC0, 0x5A, 0x00)
            _set_run_highlight(run, WD_COLOR_INDEX.YELLOW)


def _prov_field(row: object, key: str) -> Any:
    """Read a provenance field from a Pydantic model or dict."""
    if hasattr(row, key):
        return getattr(row, key)
    if isinstance(row, dict):
        return row.get(key)
    return None


def _add_transparency_and_sources(doc: DocxDocument, payload: SectionPayload) -> None:
    """Print estimated AI involvement and retrieved-source citations (DOCX)."""
    trx = getattr(payload, "ai_transparency", None)
    if isinstance(trx, dict):
        pct = trx.get("ai_involvement_percent")
        if pct is not None:
            p = doc.add_paragraph()
            r = p.add_run(f"Estimated AI involvement: {pct}%")
            r.font.bold = True
            r.font.size = Pt(9)
            r.font.color.rgb = RGBColor(0x2E, 0x5E, 0x7E)
            try:
                pct_val = int(pct)
            except (TypeError, ValueError):
                pct_val = 0
            if pct_val > 70:
                pw = doc.add_paragraph()
                rw = pw.add_run(
                    f"\u26a0 WARNING: this section was generated with {pct_val}% AI "
                    "involvement due to limited source notes. High scrutiny "
                    "required before sign-off."
                )
                rw.font.bold = True
                rw.font.size = Pt(9)
                rw.font.color.rgb = RGBColor(0xB0, 0x3A, 0x2E)
            summary = (trx.get("plain_language") or trx.get("summary") or "").strip()
            if summary:
                p2 = doc.add_paragraph()
                short = summary if len(summary) <= 480 else summary[:477] + "…"
                r2 = p2.add_run(short)
                r2.font.size = Pt(8.5)
                r2.font.italic = True
                r2.font.color.rgb = RGBColor(0x6A, 0x7A, 0x8A)
            trans = trx.get("transformations")
            if isinstance(trans, list) and trans:
                p3 = doc.add_paragraph()
                bullets = " · ".join(str(t) for t in trans[:5])
                r3 = p3.add_run("Transformations: " + bullets)
                r3.font.size = Pt(8)
                r3.font.color.rgb = RGBColor(0x55, 0x66, 0x77)
            p.paragraph_format.space_after = Pt(4)

    prov = getattr(payload, "provenance", None)
    if not isinstance(prov, list) or not prov:
        return

    head = doc.add_paragraph()
    rh = head.add_run("Source references (your uploaded documents)")
    rh.font.bold = True
    rh.font.size = Pt(9)
    rh.font.color.rgb = RGBColor(0x1B, 0x3A, 0x5C)
    head.paragraph_format.space_before = Pt(2)

    for i, row in enumerate(prov, 1):
        fn = _prov_field(row, "filename") or "Your upload"
        score = _prov_field(row, "score")
        hint = (_prov_field(row, "section_hint") or "").strip()
        snip = (_prov_field(row, "snippet_preview") or "").strip()

        line1 = doc.add_paragraph()
        line1.paragraph_format.left_indent = Inches(0.15)
        t1 = line1.add_run(f"[{i}] {fn}")
        t1.font.size = Pt(8.5)
        if score is not None:
            try:
                sc = float(score)
                t2 = line1.add_run(f"  ·  relevance {sc:.3f}")
            except (TypeError, ValueError):
                t2 = line1.add_run("")
            t2.font.size = Pt(8)
            t2.font.color.rgb = RGBColor(0x6A, 0x7A, 0x8A)
        if hint:
            h = doc.add_paragraph()
            h.paragraph_format.left_indent = Inches(0.3)
            hr = h.add_run(hint if len(hint) <= 220 else hint[:217] + "…")
            hr.font.italic = True
            hr.font.size = Pt(8)
            hr.font.color.rgb = RGBColor(0x70, 0x80, 0x90)
        if snip:
            s = doc.add_paragraph()
            s.paragraph_format.left_indent = Inches(0.3)
            stext = snip if len(snip) <= 360 else snip[:357] + "…"
            sr = s.add_run(stext)
            sr.font.size = Pt(7.5)
            sr.font.color.rgb = RGBColor(0x55, 0x66, 0x77)


def _add_editor_notes(doc: DocxDocument, notes_text: str) -> None:
    """Render proofread editor notes in an indented italic callout."""
    p = doc.add_paragraph()
    p.paragraph_format.left_indent = Inches(0.4)
    p.paragraph_format.space_before = Pt(2)
    p.paragraph_format.space_after = Pt(8)
    rl = p.add_run("📋 Editor notes: ")
    rl.font.bold = True
    rl.font.size = Pt(10)
    rl.font.color.rgb = RGBColor(0x1B, 0x3A, 0x5C)
    rn = p.add_run(notes_text)
    rn.font.italic = True
    rn.font.size = Pt(10)
    rn.font.color.rgb = RGBColor(0x44, 0x55, 0x66)


def _add_verify_legend(doc: DocxDocument) -> None:
    """Legacy no-op (kept for backwards compatibility)."""
    return


# ── XML helper ────────────────────────────────────────────────────────────────

def _set_run_highlight(run: Run, color_index: WD_COLOR_INDEX) -> None:
    """Apply a highlight colour to a run via direct OOXML (works across all python-docx versions)."""
    run_props = run._r.get_or_add_rPr()
    highlight = OxmlElement("w:highlight")
    highlight.set(
        qn("w:val"),
        color_index.name.lower() if hasattr(color_index, "name") else "yellow",
    )
    run_props.append(highlight)