from datetime import datetime
import re
import markdown
from jinja2 import Environment, FileSystemLoader, select_autoescape
from weasyprint import HTML

from cbh.api.reports.dto import StackType, ToolScore, ToolType
from cbh.api.reports.models import ReportModel
from cbh.core.config import settings


_STACK_TYPE_LABELS = {
    StackType.RECOMMENDED: "Recommended",
    StackType.FASTEST: "Fastest",
    StackType.CHEAPEST: "Cheapest",
}

_TOOL_TYPE_LABELS = {
    ToolType.RECOMMENDED: "Recommended",
    ToolType.ALTERNATIVE: "Alternative",
}

_TOOL_SCORE_LABELS = {
    ToolScore.GREAT: "Great",
    ToolScore.GOOD: "Good",
    ToolScore.AVERAGE: "Average",
    ToolScore.POOR: "Poor",
}

_TOOL_SCORE_CLASSES = {
    ToolScore.GREAT: "great",
    ToolScore.GOOD: "good",
    ToolScore.AVERAGE: "average",
    ToolScore.POOR: "poor",
}

_MARKDOWN_EXTENSIONS = ["extra", "sane_lists", "nl2br"]


def _render_markdown(value: str | None) -> str:
    if not value:
        return ""
    return markdown.markdown(
        value, extensions=_MARKDOWN_EXTENSIONS, output_format="html5"
    )


def _get_template_env() -> Environment:
    templates_path = settings.BASE_DIR / "cbh" / "templates" / "report"
    env = Environment(
        loader=FileSystemLoader(str(templates_path)),
        autoescape=select_autoescape(["html", "xml"]),
    )
    env.globals["stack_type_label"] = lambda t: _STACK_TYPE_LABELS.get(t, str(t))
    env.globals["tool_type_label"] = lambda t: _TOOL_TYPE_LABELS.get(t, str(t))
    env.globals["tool_score_label"] = lambda s: _TOOL_SCORE_LABELS.get(s, str(s))
    env.globals["tool_score_class"] = lambda s: _TOOL_SCORE_CLASSES.get(s, "good")
    return env


def _resolve_recipient_name(report: ReportModel) -> str:
    account = report.account
    return account.name or account.email or "Founder"


def _normalize_stack(report: ReportModel) -> list:
    normalized = []
    for group in report.stack or []:
        if isinstance(group, dict):
            continue
        if not getattr(group, "tools", None):
            continue
        normalized.append(group)
    return normalized


def download_report_obj(report: ReportModel) -> bytes:
    """
    Render a report as a styled PDF document and return raw PDF bytes.
    """
    env = _get_template_env()
    template = env.get_template("base.html")

    html_content = template.render(
        report=report,
        recipient_name=_resolve_recipient_name(report),
        generated_at=datetime.utcnow().strftime("%B %d, %Y"),
        stack=_normalize_stack(report),
        review_html=_render_markdown(report.review),
        deep_analysis_html=_render_markdown(report.deepAnalysis),
        monetization_html=_render_markdown(report.monetization),
        risks_html=_render_markdown(report.risks),
        marketing_plan_html=_render_markdown(report.marketingPlan),
        next_steps_html=_render_markdown(report.nextSteps),
    )

    return HTML(string=html_content).write_pdf()


def prepare_filename(name: str) -> str:
    safe_name = re.sub(r"[^A-Za-z0-9._-]+", "_", name).strip("_") or "report"
    return f"{safe_name}.pdf"