"""`alerts` (harnessx-removal Requirement 6.3, design section 6): what the deterministic rules say about a case.

No model, budget ``{usd: 0, calls: 0}``, serialized like ``repo-facts`` (a full-tree
scan per pin). It runs the quick-mode scan -- ``preprocess_repository``, the entry-point reachability hints,
``rank_targets`` and ``quick_scan_findings`` over the image's bundled ruleset, enabled and shadow rules alike, exactly
what ``ousast scan --mode quick`` runs -- on the case's vulnerable pin and on its fixed pin, and writes one row per
(rule, file, line, pin) to ``alerts.jsonl``:

    rule_id, rule_status (enabled | shadow), path, line, function, pin_role (vulnerable | fixed), pin, in_fix_range

``function`` is the enclosing declaration by the patterns ``repo-facts`` uses (so an alert joins the verify
candidates' ``path::function``; ``<module>`` outside any function); a language those patterns do not cover keeps the
scan's own reachability attribution. ``in_fix_range`` says whether the line lies inside the fix: the old-side ranges
of ``case.json`` on the vulnerable pin, the new-side ``fixed_ranges`` on the fixed pin (null when ``case.json`` has
none). A fixed-pin alert inside the fix is a false alert on code the fix wrote.

**Coverage** (an honest zero): quick mode has rules only for the languages its ruleset declares
(:func:`quick_languages`, derived from the bundled ruleset directory, never listed by hand). ``summary.json`` records
per language of the files the scan read whether quick mode covers it -- ``coverage: {language: {"coverage": "quick" |
"none", "files": {role: n}}}`` -- and ``uncovered``, the languages with ``none``. Zero alerts on an uncovered
language is not a clean result: nothing could have fired. ``remember`` turns the coverage into ``coverage`` rows,
and M1/M2 skip a repository and pin whose coverage for a rule's language is ``none``. The deterministic engine covers
more languages (:func:`engine_languages`, PHP among them); ``ousast plane alerts-engine`` (:mod:`..engine_alerts`)
produces those alerts on the host, where the engine image runs, and marks this task done.

Env: ``OUSAST_OUTPUT_DIR``, ``OUSAST_WORKSPACE_DIR`` (vulnerable checkout), ``OUSAST_FIXED_DIR`` (fixed checkout),
``OUSAST_INPUT_CASE`` (``case.json``), ``OUSAST_VULNERABLE_PIN``, ``OUSAST_FIXED_PIN``. A pin whose checkout yields no
source file fails the task: an unread tree and a silent one are indistinguishable afterwards. Exit 0 done, 2 failed.
"""

from __future__ import annotations

import json
import os
import sys
import traceback
from collections.abc import Iterable, Mapping, Sequence
from pathlib import Path
from typing import Any

from ...findings import quick_scan_findings
from ...mapping import analyze_entry_points, attach_reachability_hints
from ...preprocess import detect_language, preprocess_repository
from ...rank import rank_targets
from ...ruleset import DEFAULT_RULESET_DIR, load_ruleset
from ...source import DECLARATION, MODULE_FUNCTION
from ...source import enclosing_at as enclosing

ROLES = ("vulnerable", "fixed")
DIRS = ("OUSAST_WORKSPACE_DIR", "OUSAST_FIXED_DIR")
PINS = ("OUSAST_VULNERABLE_PIN", "OUSAST_FIXED_PIN")
ANY_LANGUAGE = "*"  # a rule that names no language runs on every file
Ranges = Mapping[str, Sequence[Sequence[int]]]


def quick_languages(directory: Path = DEFAULT_RULESET_DIR) -> frozenset[str]:
    """The languages quick mode has a rule for: the ``languages`` of every rule the ruleset directory holds that is
    not disabled (``*`` when a rule names none: it runs on every file)."""
    covered: set[str] = set()
    for rule in load_ruleset(directory):
        if rule.status != "disabled":
            covered.update(rule.languages or (ANY_LANGUAGE,))
    return frozenset(covered)


def engine_languages(directory: Path = DEFAULT_RULESET_DIR) -> frozenset[str]:
    """The languages the deterministic engine has a semantic model for: one ``semantic/<language>.toml`` each."""
    return frozenset(path.stem for path in (directory / "semantic").glob("*.toml"))


def covers(covered: Iterable[str], language: str) -> bool:
    languages = set(covered)
    return ANY_LANGUAGE in languages or language in languages


def coverage(files: Mapping[str, Mapping[str, int]], quick: Iterable[str], engine: Iterable[str] = ()) -> dict[str, dict[str, Any]]:
    """Per language of the files read (``{role: {language: n}}``): ``quick`` when quick mode has a rule for it,
    ``engine`` when the engine's alerts were produced for it, else ``none``, with the file count per role."""
    quick, engine = set(quick), set(engine)
    result: dict[str, dict[str, Any]] = {}
    for role in sorted(files):
        for language, number in files[role].items():
            if language == "unknown":
                continue
            kind = "quick" if covers(quick, language) else "engine" if language in engine else "none"
            entry = result.setdefault(language, {"coverage": kind, "files": {}})
            entry["files"][role] = int(number)
    return dict(sorted(result.items()))


def uncovered(cov: Mapping[str, Mapping[str, Any]]) -> list[str]:
    return sorted(language for language, entry in cov.items() if entry.get("coverage") == "none")


def _lines(path: Path) -> list[str]:
    try:
        return path.read_text(encoding="utf-8", errors="replace").splitlines()
    except OSError:
        return []


def in_range(ranges: Ranges | None, path: str, line: int | None) -> bool | None:
    if ranges is None:
        return None
    return line is not None and any(int(lo) <= line <= int(hi) for lo, hi in ranges.get(path, []))


def function_at(root: Path, path: str, line: int | None, fallback: str | None, cache: dict[str, list[str]]) -> str:
    """The enclosing declaration of ``path:line`` by the ``repo-facts`` patterns, else ``fallback`` (``<module>``)."""
    lines = cache.setdefault(path, _lines(root / path))
    language = detect_language(root / path)
    if language in DECLARATION and line and 0 < line <= len(lines):
        return enclosing(lines, line - 1, language)
    return fallback or MODULE_FUNCTION


def scan(root: Path, role: str, pin: str, ranges: Ranges | None) -> tuple[list[dict[str, Any]], dict[str, Any]]:
    """(rows, what was read) of one pin: the quick-mode findings as alert rows, one per rule, file, line; what was read
    counts files and bytes, and files per language."""
    _, targets = preprocess_repository(root)
    targets = attach_reachability_hints(targets, analyze_entry_points(root, targets))
    findings = quick_scan_findings(root, targets, rank_targets(targets))
    languages: dict[str, int] = {}
    for target in targets:
        languages[target.language] = languages.get(target.language, 0) + 1
    read = {
        "files": len(targets), "bytes": sum((root / t.path).stat().st_size for t in targets if (root / t.path).is_file()),
        "languages": dict(sorted(languages.items())),
    }  # fmt: skip
    cache: dict[str, list[str]] = {}
    rows: dict[tuple[str, str, int | None], dict[str, Any]] = {}
    for finding in findings:
        rule_id = finding.finding_id.split(":", 1)[0]
        row = {
            "rule_id": rule_id, "rule_status": finding.status, "path": finding.path, "line": finding.line,
            "function": function_at(root, finding.path, finding.line, finding.function_name, cache),
            "pin_role": role, "pin": pin, "in_fix_range": in_range(ranges, finding.path, finding.line),
        }  # fmt: skip
        rows.setdefault((rule_id, finding.path, finding.line), row)
    ordered = sorted(rows.values(), key=lambda r: (r["path"], r["line"] or 0, r["rule_id"]))
    return ordered, read


def write_summary(output_dir: Path, summary: Mapping[str, Any]) -> None:
    (output_dir / "summary.json").write_text(json.dumps(summary, indent=2, sort_keys=True) + "\n", encoding="utf-8")


def write_rows(output_dir: Path, rows: Iterable[Mapping[str, Any]]) -> None:
    (output_dir / "alerts.jsonl").write_text("".join(json.dumps(r, sort_keys=True) + "\n" for r in rows), encoding="utf-8")


def main(environ: Mapping[str, str] | None = None) -> int:
    env = environ if environ is not None else os.environ
    output = Path(env["OUSAST_OUTPUT_DIR"]) if env.get("OUSAST_OUTPUT_DIR") else None
    summary: dict[str, Any] = {"status": "failed", "units_done": 0, "units_total": 2, "usd": 0, "calls": 0, "usage": {}, "model": None}
    try:
        if output is None:
            raise ValueError("OUSAST_OUTPUT_DIR is not set")
        output.mkdir(parents=True, exist_ok=True)
        case = json.loads(Path(env["OUSAST_INPUT_CASE"]).read_text(encoding="utf-8")) if env.get("OUSAST_INPUT_CASE") else {}
        ranges = {"vulnerable": case.get("ranges"), "fixed": case.get("fixed_ranges")}
        rows: list[dict[str, Any]] = []
        files: dict[str, dict[str, int]] = {}
        for role, directory, pin in zip(ROLES, DIRS, PINS, strict=True):
            root = Path(env.get(directory) or "")
            if not env.get(directory) or not root.is_dir():
                raise ValueError(f"{directory} is not a directory: {root}")
            found, read = scan(root, role, str(env.get(pin) or ""), ranges[role])
            if read["files"] == 0:
                raise ValueError(f"the {role} checkout {root} has no source file the scan reads: an unread tree is not a clean one")
            files[role] = read.pop("languages")
            summary.setdefault("read", {})[role] = read
            summary.setdefault("alerts", {})[role] = len(found)
            summary.setdefault("pins", {})[role] = str(env.get(pin) or "")
            rows.extend(found)
            summary["units_done"] += 1
        quick = quick_languages()
        summary["quick_languages"] = sorted(quick)
        summary["coverage"] = coverage(files, quick)
        summary["uncovered"] = uncovered(summary["coverage"])
        write_rows(output, rows)
        summary["status"] = "done"
    except Exception:  # noqa: BLE001 -- a crash is `failed` with its traceback
        summary["reason"] = traceback.format_exc()[-2000:]
    if output is not None:
        write_summary(output, summary)
    print(json.dumps({k: summary.get(k) for k in ("status", "alerts", "read", "uncovered")}), file=sys.stderr)
    return 0 if summary["status"] == "done" else 2


__all__ = ["coverage", "covers", "engine_languages", "function_at", "in_range", "main", "quick_languages", "scan", "uncovered"]


if __name__ == "__main__":
    raise SystemExit(main())