"""Pipeline adapter for decoding creation candidate items."""
from __future__ import annotations

from dataclasses import dataclass, field
from typing import Protocol
from uuid import UUID

from acquisition.domain import CandidateItem, MediaAsset
from core.text_limits import ERROR_MESSAGE_MAX_CHARS, clip_text
from decode_content.readers.service import post_from_candidate_item
from decode_content.service import DecodeService, DecodeWorkflowOutput
from pipeline.dedupe import dedupe_candidate_items, should_decode_item
from pipeline.tracing import NoopTraceWriter, TraceContext, TraceWriter


class DecodeCandidateRepository(Protocol):
    def list_creation_candidate_items(
        self,
        *,
        run_id: UUID | None = None,
        limit: int = 100,
    ) -> list[CandidateItem]:
        ...

    def list_media_assets_for_item(self, item_id: UUID) -> list[MediaAsset]:
        ...


@dataclass(frozen=True)
class DecodeBatchResult:
    total: int
    decoded: int
    skipped: int
    failed: int
    outputs: list[DecodeWorkflowOutput]
    failures: list[dict[str, str]] = field(default_factory=list)


def _record_failure(decode_service: DecodeService, item: CandidateItem, exc: Exception) -> dict[str, str]:
    message = clip_text(str(exc) or exc.__class__.__name__, ERROR_MESSAGE_MAX_CHARS)
    failure = {
        "item_id": str(item.id),
        "platform": item.platform,
        "title": item.title or "",
        "error": message,
    }
    repo = getattr(decode_service, "repository", None)
    if repo is not None and item.id is not None:
        mark_jobs = getattr(repo, "mark_running_decode_jobs_failed", None)
        if mark_jobs is not None:
            mark_jobs(item.id, message)
        save_result = getattr(repo, "save_decode_result", None)
        if save_result is not None:
            save_result(
                item_id=item.id,
                read_result={"is_empty": True, "text": "", "metadata": {"decode_error": message}},
                gate_result={"passed": False, "reason": "decode_failed", "details": {"error": message}},
                framing_result={"error": message},
                status="failed",
            )
    return failure


def run_decode_stage(
    *,
    candidate_repo: DecodeCandidateRepository,
    decode_service: DecodeService,
    run_id: UUID | None = None,
    limit: int = 100,
    decoded_item_ids: set[str] | None = None,
    trace_writer: TraceWriter | None = None,
    trace_context: TraceContext | None = None,
) -> DecodeBatchResult:
    items = dedupe_candidate_items(candidate_repo.list_creation_candidate_items(run_id=run_id, limit=limit))
    trace_writer = trace_writer or NoopTraceWriter()
    base_context = trace_context or TraceContext(acquisition_run_id=run_id, stage="decode")
    trace_writer.event(
        context=base_context,
        stage="decode",
        event_type="decode_stage_started",
        status="running",
        payload={"run_id": str(run_id) if run_id else None, "candidate_count": len(items), "limit": limit},
    )
    outputs: list[DecodeWorkflowOutput] = []
    failures: list[dict[str, str]] = []
    decoded = skipped = failed = 0
    for item in items:
        if item.id is None:
            skipped += 1
            trace_writer.event(
                context=base_context.child(platform=item.platform),
                stage="decode",
                event_type="decode_item_skipped",
                status="skipped",
                payload={"reason": "missing_item_id", "title": item.title or ""},
            )
            continue
        item_context = base_context.child(
            item_id=item.id,
            acquisition_job_id=item.job_id,
            query_id=item.query_id,
            platform=item.platform,
        )
        decision = should_decode_item(item, decoded_item_ids=decoded_item_ids)
        if not decision.keep:
            skipped += 1
            trace_writer.event(
                context=item_context,
                stage="decode",
                event_type="decode_item_skipped",
                status="skipped",
                target_table="candidate_items",
                target_id=item.id,
                payload={"reason": decision.reason},
            )
            continue
        try:
            trace_writer.event(
                context=item_context,
                stage="decode",
                event_type="decode_item_started",
                status="running",
                target_table="candidate_items",
                target_id=item.id,
            )
            media = candidate_repo.list_media_assets_for_item(item.id)
            post = post_from_candidate_item(item, media)
            outputs.append(decode_service.decode_post(item_id=item.id, post=post))
            decoded += 1
            trace_writer.event(
                context=item_context,
                stage="decode",
                event_type="decode_item_finished",
                status="done",
                target_table="candidate_items",
                target_id=item.id,
            )
        except Exception as exc:
            failed += 1
            failures.append(_record_failure(decode_service, item, exc))
            trace_writer.event(
                context=item_context,
                stage="decode",
                event_type="decode_item_failed",
                status="failed",
                severity="error",
                target_table="candidate_items",
                target_id=item.id,
                error_message=str(exc),
            )
    trace_writer.event(
        context=base_context,
        stage="decode",
        event_type="decode_stage_finished",
        status="done" if failed == 0 else "partial",
        payload={"total": len(items), "decoded": decoded, "skipped": skipped, "failed": failed},
    )
    return DecodeBatchResult(
        total=len(items),
        decoded=decoded,
        skipped=skipped,
        failed=failed,
        outputs=outputs,
        failures=failures,
    )