"""immich-go report parsing (US05-03).

The uploader's output is the only local evidence of what Immich did with each file,
and its wording changes between releases (concept §15 "external integration
risks"). So parsing is deliberately conservative:

- **the parser is chosen by uploader version, not by guessing the format.** Each
  supported version family maps to one adapter with a pinned line grammar. An
  unrecognised version yields no adapter at all, which makes every item uncertain
  rather than optimistically successful.
- **an unmatched line is never success.** Lines the adapter does not recognise are
  counted (``unparsed``) and kept as evidence; they never classify an item.
- **evidence is bounded.** Each entry keeps a trimmed copy of the line that
  classified it, and the number of entries is capped, so a looping uploader cannot
  turn the report into unbounded database rows.

Two grammars are supported. ``text-v1`` is the default human-readable log of the
0.21/0.22 line, ``json-v1`` the structured log (``--log-type=json``) of 0.23/0.24.
Both classify through one shared phrase table, so the vocabulary cannot drift
between them:

```text
text-v1   INFO  uploaded /lib/rome/a.jpg
          INFO  server has the same file /lib/rome/b.jpg
          ERROR error uploading /lib/rome/e.jpg: connection reset
          Uploaded 1, duplicates 1, errors 1

json-v1   {"level":"INFO","msg":"uploaded","file":"/lib/rome/a.jpg"}
          {"level":"INFO","msg":"report","counts":{"uploaded":1}}
```

Nothing here touches the database; :mod:`photo_pipeline.services.upload_reports`
turns a parse result into durable per-item outcomes.
"""

from __future__ import annotations

import json
import re

PARSER_VERSION = 1

# Per-item outcomes. ``UNKNOWN`` is the safe default everywhere: it means the app
# does not know what happened to that file and US05-04 must verify it.
UPLOADED = "uploaded"
UPGRADED = "upgraded"
DUPLICATE = "duplicate"
SKIPPED = "skipped"
FAILED = "failed"
UNKNOWN = "unknown"

OUTCOMES = (UPLOADED, UPGRADED, DUPLICATE, SKIPPED, FAILED, UNKNOWN)

# Longest/most specific phrases first: "server has an older file" also contains
# "server has", and an error line about uploading also contains "upload".
_PHRASES: tuple[tuple[str, str], ...] = (
    ("server has the same file", DUPLICATE),
    ("server has an older file", UPGRADED),
    ("upgraded", UPGRADED),
    ("duplicate", DUPLICATE),
    ("discarded", SKIPPED),
    ("skipped", SKIPPED),
    ("error", FAILED),
    ("failed", FAILED),
    ("uploaded", UPLOADED),
    ("upload", UPLOADED),
)

# Summary line of the text grammar: "Uploaded 3, duplicates 1, errors 2".
_SUMMARY_WORDS = {
    "uploaded": UPLOADED,
    "upgraded": UPGRADED,
    "duplicates": DUPLICATE,
    "duplicate": DUPLICATE,
    "skipped": SKIPPED,
    "discarded": SKIPPED,
    "errors": FAILED,
    "error": FAILED,
}
_SUMMARY_PAIR = re.compile(r"([A-Za-z]+)\s+(\d+)")
# A path is anything that looks absolute, up to an explanatory ": reason" tail.
_PATH = re.compile(r"(/[^\s:][^:]*?)(?=:|$)")

MAX_EVIDENCE_CHARS = 300
# The report file is already byte-capped; this caps the rows it can produce.
MAX_ENTRIES = 20_000


def parser_for(uploader_version: str | None) -> str | None:
    """Adapter name for a recorded uploader version, or ``None`` when unsupported.

    Unsupported is not an error — it is the honest answer that this build's output
    format was never pinned, and it makes the whole report uncertain.
    """
    match = re.search(r"(\d+)\.(\d+)", uploader_version or "")
    if match is None:
        return None
    return _SUPPORTED.get(f"{match.group(1)}.{match.group(2)}")


def parse(report: str, uploader_version: str | None) -> dict:
    """Classify a raw report.

    Returns ``{"parser", "parser_version", "supported", "entries", "counts",
    "unparsed", "entries_truncated"}`` where ``entries`` is a list of
    ``{"path", "outcome", "evidence"}`` and ``counts`` is the uploader's own
    summary when it printed one (``None`` otherwise, never invented).
    """
    parser = parser_for(uploader_version)
    result = {
        "parser": parser,
        "parser_version": PARSER_VERSION,
        "supported": parser is not None,
        "entries": [],
        "counts": None,
        "unparsed": 0,
        "entries_truncated": False,
    }
    if parser is None:
        return result
    read_line = _text_line if parser == "text-v1" else _json_line
    for raw in report.splitlines():
        line = raw.strip()
        if not line:
            continue
        path, outcome, counts = read_line(line)
        if counts is not None:
            # Later summaries win: the uploader prints its totals once, at the end.
            result["counts"] = counts
            continue
        if path is None or outcome is None:
            result["unparsed"] += 1
            continue
        if len(result["entries"]) >= MAX_ENTRIES:
            result["entries_truncated"] = True
            continue
        result["entries"].append(
            {"path": path, "outcome": outcome, "evidence": line[:MAX_EVIDENCE_CHARS]}
        )
    return result


def _classify(text: str) -> str | None:
    lowered = text.lower()
    for phrase, outcome in _PHRASES:
        if phrase in lowered:
            return outcome
    return None


def _summary(text: str) -> dict[str, int] | None:
    """Totals from a summary line, or ``None`` when the line is not one."""
    counts: dict[str, int] = {}
    for word, number in _SUMMARY_PAIR.findall(text):
        outcome = _SUMMARY_WORDS.get(word.lower())
        if outcome is None:
            return None  # an unknown noun means this is not the summary grammar
        counts[outcome] = counts.get(outcome, 0) + int(number)
    return counts or None


def _text_line(line: str) -> tuple[str | None, str | None, dict | None]:
    path_match = _PATH.search(line)
    if path_match is None:
        return None, None, _summary(line)
    path = path_match.group(1).strip()
    # Classify from the words around the path, never from the path itself: an
    # album called "errors" must not turn an upload into a failure.
    context = line.replace(path, " ")
    return path, _classify(context), None


def _json_line(line: str) -> tuple[str | None, str | None, dict | None]:
    try:
        record = json.loads(line)
    except ValueError:
        return None, None, None
    if not isinstance(record, dict):
        return None, None, None
    counts = record.get("counts")
    if isinstance(counts, dict):
        totals = {
            _SUMMARY_WORDS[key.lower()]: int(value)
            for key, value in counts.items()
            if key.lower() in _SUMMARY_WORDS and isinstance(value, int)
        }
        return None, None, totals or None
    path = record.get("file")
    message = record.get("msg")
    if not isinstance(path, str) or not isinstance(message, str):
        return None, None, None
    return path, _classify(message), None


# Version family → adapter. Pinning this is the point: a build outside the list is
# uncertain by construction (concept §15 "pin and record supported immich-go
# versions").
_SUPPORTED = {
    "0.21": "text-v1",
    "0.22": "text-v1",
    "0.23": "json-v1",
    "0.24": "json-v1",
}
SUPPORTED_VERSIONS = tuple(sorted(_SUPPORTED))