from __future__ import annotations

import time
import uuid
from dataclasses import dataclass
from enum import StrEnum
from typing import Protocol

from django.utils import timezone

from control_plane.agents.models import AgentVersion
from control_plane.projects.models import Project
from control_plane.resources.models import ModelRequest, Resource
from model_router.policy import model_for_purpose


class ModelCapability(StrEnum):
    PROJECT_BRAIN = "PROJECT_BRAIN"
    PLANNING = "PLANNING"
    ARCHAEOLOGY_INTERPRETATION = "ARCHAEOLOGY_INTERPRETATION"
    CODING = "CODING"
    REVIEW = "REVIEW"
    REASONING = "REASONING"


@dataclass(frozen=True)
class ModelRequestContract:
    purpose: str
    prompt: str
    model_hint: str | None = None
    token_budget: int = 8000
    project: Project | None = None
    agent_version: AgentVersion | None = None


@dataclass(frozen=True)
class ModelResponseContract:
    model: str
    content: str
    metadata: dict[str, object]


class ModelProvider(Protocol):
    provider_name: str

    def complete(self, request: ModelRequestContract) -> ModelResponseContract: ...

    def health(self) -> str: ...


class ModelRouter:
    def __init__(self, providers: dict[str, ModelProvider] | None = None, persist_requests: bool = False) -> None:
        self.providers = providers or {}
        self.persist_requests = persist_requests

    def route(self, purpose: str) -> str:
        return model_for_purpose(str(purpose))

    def complete(self, request: ModelRequestContract) -> ModelResponseContract:
        provider_key = request.model_hint or self.route(request.purpose)
        provider = self.providers.get(provider_key)
        if provider is None:
            raise RuntimeError(f"No model provider configured for {provider_key}")
        model_resource = self._resource_for(provider_key, request.purpose)
        record = self._start_record(request, provider, model_resource)
        started = time.monotonic()
        try:
            response = provider.complete(request)
        except Exception as exc:
            if record is not None:
                self._finish_record(record, "FAILED", None, started, failure_reason=str(exc))
            raise
        if record is not None:
            self._finish_record(record, "COMPLETE", response, started)
        return response

    def health(self) -> dict[str, str]:
        statuses: dict[str, str] = {}
        for key, provider in self.providers.items():
            try:
                statuses[key] = provider.health()
            except Exception:
                statuses[key] = "UNAVAILABLE"
        return statuses

    def _resource_for(self, provider_key: str, purpose: str) -> Resource | None:
        role = purpose.upper()
        candidates = list(Resource.objects.filter(is_active=True))
        provider_names = {provider_key}
        if provider_key == "qwen":
            provider_names.add("local_inference")
        if provider_key in {"sol", "terra", "luna"}:
            provider_names.add("opencode")
        for resource in candidates:
            if resource.config.get("model_key") == provider_key:
                return resource
        for resource in candidates:
            if resource.provider in provider_names and role in resource.roles:
                return resource
        for resource in candidates:
            if resource.provider in provider_names:
                return resource
        return None

    def _start_record(self, request: ModelRequestContract, provider: ModelProvider, resource: Resource | None) -> ModelRequest | None:
        if not self.persist_requests:
            return None
        return ModelRequest.objects.create(
            correlation_id=uuid.uuid4().hex,
            project=request.project,
            agent_version=request.agent_version,
            logical_role=request.purpose.upper(),
            model_resource=resource,
            provider=provider.provider_name,
            model=resource.name if resource else request.model_hint or self.route(request.purpose),
            token_budget=request.token_budget,
            status="IN_PROGRESS",
            started_at=timezone.now(),
            request={"prompt_chars": len(request.prompt), "contains_raw_prompt": False},
        )

    def _finish_record(
        self,
        record: ModelRequest,
        status: str,
        response: ModelResponseContract | None,
        started: float,
        *,
        failure_reason: str = "",
    ) -> None:
        record.status = status
        record.ended_at = timezone.now()
        record.latency_ms = int((time.monotonic() - started) * 1000)
        record.failure_reason = failure_reason
        if response is not None:
            usage = response.metadata.get("usage", {}) if isinstance(response.metadata, dict) else {}
            record.prompt_tokens = usage.get("prompt_tokens") if isinstance(usage, dict) else None
            record.completion_tokens = usage.get("completion_tokens") if isinstance(usage, dict) else None
            record.response = {"content_chars": len(response.content), "model": response.model, "metadata_keys": sorted(response.metadata.keys())}
        record.save(
            update_fields=[
                "status",
                "ended_at",
                "latency_ms",
                "failure_reason",
                "prompt_tokens",
                "completion_tokens",
                "response",
                "updated_at",
            ]
        )