"""Markdown bible -> raw yaml-block entries. Knows only fences + YAML; nothing
about the schema's meaning. A block is opened by a line that is exactly ```yaml
(after strip) and closed by a line that is exactly ```."""

from dataclasses import dataclass
from pathlib import Path

import yaml

from .errors import BuildError


@dataclass
class RawEntry:
    data: dict
    source: str  # "duncarrow.md:53"


def parse_bible(path: Path) -> list[RawEntry]:
    lines = path.read_text().splitlines()
    entries: list[RawEntry] = []
    i, n = 0, len(lines)
    while i < n:
        if lines[i].strip() == "```yaml":
            fence_line = i + 1  # 1-based line of the opening fence
            i += 1
            block: list[str] = []
            while i < n and lines[i].strip() != "```":
                block.append(lines[i])
                i += 1
            if i >= n:
                raise BuildError("unterminated ```yaml block",
                                 source=f"{path.name}:{fence_line}")
            data = yaml.safe_load("\n".join(block))
            if not isinstance(data, dict):
                raise BuildError("yaml block is not a mapping",
                                 source=f"{path.name}:{fence_line}")
            entries.append(RawEntry(data=data, source=f"{path.name}:{fence_line}"))
        i += 1
    return entries