from __future__ import annotations

from typing import Any, Dict, Iterable, List, Protocol, Sequence

from .models import IndexDocument
from .redmine import RedmineMapper


class RedmineSource(Protocol):
    project_identifier: str | None

    def recent_helpdesk_issues(self, limit: int) -> Iterable[Dict[str, Any]]:
        ...


class DocumentEmbedder(Protocol):
    def embed_documents(self, docs: Sequence[IndexDocument]) -> List[List[float]]:
        ...


class RebuildStore(Protocol):
    def rebuild_source(
        self,
        source: str,
        docs: Sequence[IndexDocument],
        vectors: Sequence[Sequence[float]],
        project_identifier: str | None = None,
    ) -> None:
        ...


class BackfillService:
    def __init__(self, source: RedmineSource, embedder: DocumentEmbedder, store: RebuildStore, mapper: RedmineMapper | None = None) -> None:
        self.source = source
        self.embedder = embedder
        self.store = store
        self.mapper = mapper or RedmineMapper(redmine_url="")

    def backfill_redmine_sample(self, limit: int = 500) -> Dict[str, int | str]:
        issues = list(self.source.recent_helpdesk_issues(limit))
        documents: List[IndexDocument] = []
        for issue in issues:
            documents.extend(self.mapper.issue_to_documents(issue))
        documents = deduplicate_documents(documents)
        vectors = self.embedder.embed_documents(documents) if documents else []
        self.store.rebuild_source("redmine", documents, vectors, project_identifier=self._project_identifier())
        return {"source": "redmine", "issues": len(issues), "documents": len(documents)}

    def backfill_redmine_projects(self, projects: Sequence[str], per_project_limit: int = 500) -> Dict[str, object]:
        return self.backfill_redmine_project_limits({project: per_project_limit for project in projects})

    def backfill_redmine_project_limits(self, project_limits: Dict[str, int]) -> Dict[str, object]:
        previous_source_project = getattr(self.source, "project_identifier", None)
        previous_mapper_project = getattr(self.mapper, "project_identifier", None)
        project_results: List[Dict[str, int | str]] = []
        total_issues = 0
        total_documents = 0
        try:
            for project, project_limit in project_limits.items():
                if hasattr(self.source, "project_identifier"):
                    self.source.project_identifier = project
                if hasattr(self.mapper, "project_identifier"):
                    self.mapper.project_identifier = project
                issues = list(self.source.recent_helpdesk_issues(project_limit))
                documents: List[IndexDocument] = []
                for issue in issues:
                    documents.extend(self.mapper.issue_to_documents(issue))
                documents = deduplicate_documents(documents)
                vectors = self.embedder.embed_documents(documents) if documents else []
                self.store.rebuild_source("redmine", documents, vectors, project_identifier=project)
                project_results.append(
                    {"project_identifier": project, "issues": len(issues), "documents": len(documents)}
                )
                total_issues += len(issues)
                total_documents += len(documents)
        finally:
            if hasattr(self.source, "project_identifier"):
                self.source.project_identifier = previous_source_project
            if hasattr(self.mapper, "project_identifier"):
                self.mapper.project_identifier = previous_mapper_project
        return {
            "source": "redmine",
            "projects": len(project_limits),
            "issues": total_issues,
            "documents": total_documents,
            "project_results": project_results,
        }

    def _project_identifier(self) -> str | None:
        mapper_project = getattr(self.mapper, "project_identifier", None)
        if mapper_project:
            return mapper_project
        return getattr(self.source, "project_identifier", None)


def deduplicate_documents(documents: Sequence[IndexDocument]) -> List[IndexDocument]:
    unique: Dict[str, IndexDocument] = {}
    for document in documents:
        unique[document.id] = document
    return list(unique.values())