# -*- coding: utf-8 -*-
import io
import mistune
from bs4 import BeautifulSoup
from docx import Document
from docx.shared import Pt, Inches
from docx.enum.section import WD_SECTION, WD_ORIENT
from docx.enum.table import WD_CELL_VERTICAL_ALIGNMENT
from docx.oxml import OxmlElement
from docx.oxml.ns import qn
from config import APP_CONFIG


class DocxBuildError(RuntimeError):
    """Raised when markdown cannot be rendered into a valid DOCX document."""


def _manuscript_heading_structure(markdown_content, *, qualitative_appendix=False):
    """Derive unnumbered heading roles from Markdown structure, not language.

    Production manuscripts have an optional title/front-matter H1 followed by
    numbered body H1s and a final References H1. ASQ additionally has a
    penultimate Appendix H1.  The roles are identified by position and the
    existing semantic ASQ packaging flag, so translated wording is irrelevant.
    """
    tokens = mistune.create_markdown(renderer="ast", plugins=["table"])(str(markdown_content or ""))
    headings = []
    for token_index, token in enumerate(tokens):
        if not isinstance(token, dict) or token.get("type") != "heading":
            continue
        level = int((token.get("attrs") or {}).get("level") or 0)
        headings.append((token_index, level))
    h1 = [(token_index, level) for token_index, level in headings if level == 1]
    if not h1:
        return {"first_h1_is_title": False, "unnumbered_h1_ordinals": set()}
    first_h1_is_title = True
    unnumbered = set()
    if len(h1) >= 2:
        unnumbered.add(len(h1))  # final References H1
    if qualitative_appendix and len(h1) >= 3:
        unnumbered.add(len(h1) - 1)  # ASQ Appendix H1
    return {
        "first_h1_is_title": first_h1_is_title,
        "unnumbered_h1_ordinals": unnumbered,
    }


def _table_column_count(token):
    if not isinstance(token, dict) or token.get("type") != "table":
        return 0
    for child in token.get("children") or []:
        if isinstance(child, dict) and child.get("type") == "table_head":
            return len(child.get("children") or [])
    return 0


def _qualitative_appendix_table_ordinal(markdown_content):
    """Return the semantic evidence-table ordinal for an ASQ manuscript.

    The qualitative Appendix is a structural business object: the unique
    six-column Markdown table between the penultimate and final level-1
    headings (Appendix and References in the frozen manuscript architecture).
    Reader-facing header wording is intentionally irrelevant so EN/ZH/RU/KK
    translations retain the same table identity.
    """
    tokens = mistune.create_markdown(renderer="ast", plugins=["table"])(str(markdown_content or ""))
    h1_positions = [
        index for index, token in enumerate(tokens)
        if isinstance(token, dict)
        and token.get("type") == "heading"
        and int((token.get("attrs") or {}).get("level") or 0) == 1
    ]
    if len(h1_positions) < 2:
        return None
    appendix_start, references_start = h1_positions[-2], h1_positions[-1]
    table_ordinal = -1
    candidates = []
    for index, token in enumerate(tokens):
        if not isinstance(token, dict) or token.get("type") != "table":
            continue
        table_ordinal += 1
        if appendix_start < index < references_start and _table_column_count(token) == 6:
            candidates.append(table_ordinal)
    if len(candidates) != 1:
        return None
    return candidates[0]


class DocxRenderer(mistune.HTMLRenderer):
    def __init__(self, *, qualitative_appendix_table_ordinal=None, semantic_qualitative_appendix=False, first_h1_is_title=False, unnumbered_h1_ordinals=None):
        super().__init__()
        self.doc = Document()
        self.h_counters = [0] * 6
        self.h1_ordinal = 0
        self.first_h1_is_title = bool(first_h1_is_title)
        self.unnumbered_h1_ordinals = set(unnumbered_h1_ordinals or set())
        self.table_ordinal = -1
        self.qualitative_appendix_table_ordinal = qualitative_appendix_table_ordinal
        self.semantic_qualitative_appendix = bool(semantic_qualitative_appendix)
        try:
            style = self.doc.styles['Normal']
            style.font.name = APP_CONFIG["docx_styles"]["font_name"]
            style.font.size = Pt(APP_CONFIG["docx_styles"]["font_size_pt"])
        except: 
            pass

    def _render_rich_text(self, p, html_text):
        if not html_text.strip(): 
            return
            
        soup = BeautifulSoup(html_text, 'html.parser')
        for element in soup.children:
            if isinstance(element, str): 
                p.add_run(element)
            elif element.name in ['strong', 'b']: 
                p.add_run(element.get_text()).bold = True
            elif element.name in ['em', 'i']: 
                p.add_run(element.get_text()).italic = True
            elif element.name == 'code':
                run = p.add_run(element.get_text())
                run.font.name = APP_CONFIG["docx_styles"]["code_font"]
                run.font.size = Pt(APP_CONFIG["docx_styles"]["code_size_pt"])
            else: 
                p.add_run(element.get_text())

    def heading(self, text, level):
        clean_text = BeautifulSoup(text, 'html.parser').get_text().strip()
        level = int(level or 0)
        if level == 1:
            self.h1_ordinal += 1
            if (self.first_h1_is_title and self.h1_ordinal == 1) or self.h1_ordinal in self.unnumbered_h1_ordinals:
                self.doc.add_heading(clean_text, level=1)
                return ''
        elif self.first_h1_is_title and self.h1_ordinal == 1:
            # Abstract/Keywords and any other front-matter child headings are
            # structurally unnumbered regardless of language.
            self.doc.add_heading(clean_text, level=level)
            return ''
            
        idx = level - 1
        if 0 <= idx < 6:
            for j in range(idx):
                if self.h_counters[j] == 0: 
                    self.h_counters[j] = 1
                    
            self.h_counters[idx] += 1
            for i in range(idx + 1, 6): 
                self.h_counters[i] = 0
                
            num_str = ".".join(map(str, self.h_counters[0:idx+1]))
            self.doc.add_heading(f"{num_str} {clean_text}", level=level)
        else: 
            self.doc.add_heading(clean_text, level=level)
        return ''

    def paragraph(self, text):
        if text.strip(): 
            self._render_rich_text(self.doc.add_paragraph(), text)
        return ''

    def block_code(self, code, info=None):
        run = self.doc.add_paragraph().add_run(code)
        run.font.name = APP_CONFIG["docx_styles"]["code_font"]
        run.font.size = Pt(APP_CONFIG["docx_styles"]["code_size_pt"])
        return ''

    def block_quote(self, text):
        p = self.doc.add_paragraph()
        self._render_rich_text(p, text)
        try: 
            p.style = 'Intense Quote' if 'Intense Quote' in self.doc.styles else 'Normal'
        except: 
            pass
        return ''

    def list(self, text, ordered, **attrs): 
        return text

    def list_item(self, text):
        if text.strip():
            p = self.doc.add_paragraph()
            p.style = 'List Bullet'
            self._render_rich_text(p, text)
        return ''

    def table(self, text):
        soup = BeautifulSoup(text, 'html.parser')
        rows = soup.find_all('tr')
        if not rows:
            return ''

        max_cols = max(len(row.find_all(['td', 'th'])) for row in rows)
        if max_cols == 0:
            return ''

        self.table_ordinal += 1
        header_labels = [cell.get_text(strip=True) for cell in rows[0].find_all(['td', 'th'])]
        qualitative_headers = [
            'Higher-order Theme', 'Empirical Concept', 'Process Stage',
            'Case/Actor', 'Evidence Role', 'Representative Quote',
        ]
        if self.semantic_qualitative_appendix:
            qualitative_evidence_table = (
                self.qualitative_appendix_table_ordinal is not None
                and self.table_ordinal == self.qualitative_appendix_table_ordinal
            )
        else:
            # Legacy direct-render compatibility. Production ASQ packaging uses
            # the semantic structural identity above and never depends on labels.
            qualitative_evidence_table = header_labels == qualitative_headers

        if qualitative_evidence_table:
            previous = self.doc.sections[-1]
            landscape = self.doc.add_section(WD_SECTION.NEW_PAGE)
            landscape.orientation = WD_ORIENT.LANDSCAPE
            landscape.page_width, landscape.page_height = previous.page_height, previous.page_width

        table = self.doc.add_table(rows=len(rows), cols=max_cols)
        try:
            table.style = 'Table Grid'
        except:
            pass

        if qualitative_evidence_table:
            table.autofit = False
        widths = [1.15, 1.10, 0.85, 0.85, 0.75, 3.80] if qualitative_evidence_table else []
        if qualitative_evidence_table:
            for grid_col, width in zip(table._tbl.tblGrid.gridCol_lst, widths):
                grid_col.set(qn('w:w'), str(int(width * 1440)))

        for i, row in enumerate(rows):
            for j, cell in enumerate(row.find_all(['td', 'th'])):
                if j >= max_cols:
                    continue
                target = table.cell(i, j)
                target.text = cell.get_text(strip=True)
                if qualitative_evidence_table:
                    target.vertical_alignment = WD_CELL_VERTICAL_ALIGNMENT.TOP
                    target.width = Inches(widths[j])
                    tc_pr = target._tc.get_or_add_tcPr()
                    tc_w = tc_pr.first_child_found_in('w:tcW')
                    if tc_w is not None:
                        tc_w.set(qn('w:type'), 'dxa')
                        tc_w.set(qn('w:w'), str(int(widths[j] * 1440)))
                    for paragraph in target.paragraphs:
                        paragraph.paragraph_format.space_before = Pt(0)
                        paragraph.paragraph_format.space_after = Pt(0)
                        for run in paragraph.runs:
                            run.font.size = Pt(9)

        if qualitative_evidence_table and table.rows:
            header_pr = table.rows[0]._tr.get_or_add_trPr()
            header = OxmlElement('w:tblHeader')
            header.set(qn('w:val'), 'true')
            header_pr.append(header)
            for row in table.rows:
                tr_pr = row._tr.get_or_add_trPr()
                cant_split = OxmlElement('w:cantSplit')
                tr_pr.append(cant_split)

        self.doc.add_paragraph()
        if qualitative_evidence_table:
            current = self.doc.sections[-1]
            portrait = self.doc.add_section(WD_SECTION.NEW_PAGE)
            portrait.orientation = WD_ORIENT.PORTRAIT
            portrait.page_width, portrait.page_height = current.page_height, current.page_width
        return ''

    def thematic_break(self):
        self.doc.add_paragraph('_' * 50)
        return ''

    def image(self, src, alt="", title=None):
        self.doc.add_paragraph(f"[Image: {alt or src}]")
        return ''

def text_to_docx(markdown_content, *, qualitative_appendix=False):
    """Render markdown strictly; never disguise renderer failures as success.

    ``qualitative_appendix=True`` is an internal semantic contract supplied by
    ASQ packaging. It binds the deterministic evidence table by manuscript
    structure rather than reader-facing English/Chinese/Russian/Kazakh labels.
    """
    try:
        semantic_qualitative_appendix = bool(qualitative_appendix)
        qualitative_table_ordinal = None
        if semantic_qualitative_appendix:
            qualitative_table_ordinal = _qualitative_appendix_table_ordinal(markdown_content)
            if qualitative_table_ordinal is None:
                raise DocxBuildError(
                    "Qualitative Appendix semantic table identity is missing or ambiguous."
                )
        heading_structure = _manuscript_heading_structure(
            markdown_content, qualitative_appendix=semantic_qualitative_appendix
        )
        renderer = DocxRenderer(
            qualitative_appendix_table_ordinal=qualitative_table_ordinal,
            semantic_qualitative_appendix=semantic_qualitative_appendix,
            first_h1_is_title=heading_structure["first_h1_is_title"],
            unnumbered_h1_ordinals=heading_structure["unnumbered_h1_ordinals"],
        )
        mistune.create_markdown(renderer=renderer, plugins=['table'])(str(markdown_content or ''))
        doc = renderer.doc
        if not doc.paragraphs and not doc.tables:
            raise DocxBuildError("DOCX renderer produced no document content.")
        stream = io.BytesIO()
        doc.save(stream)
        stream.seek(0)
        return stream
    except DocxBuildError:
        raise
    except Exception as exc:
        raise DocxBuildError(f"DOCX rendering failed: {exc}") from exc