from __future__ import annotations

import json
import os
import re
import shlex
import subprocess
import time
import urllib.error
import urllib.request
from collections.abc import Iterator
from dataclasses import dataclass
from typing import Any

from control_plane.resources.models import Resource
from model_router.router import ModelChunk, ModelRequestContract, ModelResponseContract


class ProviderError(RuntimeError):
    pass


def _extract_json(text: str) -> dict[str, Any]:
    try:
        value = json.loads(text)
    except json.JSONDecodeError as exc:
        raise ProviderError("Provider returned malformed JSON") from exc
    if not isinstance(value, dict):
        raise ProviderError("Provider JSON response must be an object")
    return value


def extract_json_object(text: str) -> dict[str, Any]:
    try:
        return _extract_json(text)
    except ProviderError:
        start = text.find("{")
        end = text.rfind("}")
        if start == -1 or end == -1 or end <= start:
            raise
        return _extract_json(text[start : end + 1])


def _clean_opencode_output(text: str) -> str:
    text = re.sub(r"\x1b\[[0-9;?]*[ -/]*[@-~]", "", text)
    lines = []
    for line in text.splitlines():
        stripped = line.strip()
        if not stripped or stripped.startswith("> build"):
            continue
        lines.append(line)
    return "\n".join(lines).strip()


@dataclass
class SolProvider:
    resource: Resource
    provider_name: str = "opencode"

    def complete(self, request: ModelRequestContract) -> ModelResponseContract:
        config = self.resource.config
        compute = self.resource.compute
        timeout = int(config.get("timeout_seconds", 120))
        command = str(config.get("command", "opencode run"))
        transport = str(config.get("transport", "ssh"))
        use_pty = bool(config.get("use_pty", False))
        working_directory = str(config.get("working_directory") or "").strip() or None
        if transport == "local":
            argv = shlex.split(command, posix=os.name != "nt")
            if use_pty:
                shell_command = " ".join(shlex.quote(part) for part in argv)
                argv = ["script", "-q", "-e", "-c", shell_command, "/dev/null"]
            completed = subprocess.run(
                argv,
                capture_output=True,
                text=True,
                timeout=timeout,
                check=False,
                cwd=working_directory,
                input=request.prompt,
            )
        else:
            ssh_alias = (compute.config if compute else {}).get("ssh_alias", config.get("ssh_alias", "spark"))
            remote_command = " ".join(shlex.quote(part) for part in shlex.split(command))
            if working_directory:
                remote_command = f"cd {shlex.quote(working_directory)} && {remote_command}"
            completed = subprocess.run(
                ["ssh", "-T", str(ssh_alias), remote_command],
                capture_output=True,
                text=True,
                timeout=timeout,
                check=False,
                input=request.prompt,
            )
        if completed.returncode != 0:
            raise ProviderError(completed.stderr.strip() or "Sol provider failed")
        content = _clean_opencode_output(completed.stdout)
        if not content:
            raise ProviderError("Sol provider response missing content")
        return ModelResponseContract(
            model=self.resource.name,
            content=content,
            metadata={"provider": self.provider_name, "usage": {}},
        )

    def stream(self, request: ModelRequestContract) -> Iterator[ModelChunk]:
        config = self.resource.config
        command = str(config.get("command", "opencode run"))
        transport = str(config.get("transport", "ssh"))
        working_directory = str(config.get("working_directory") or "").strip() or None
        if transport == "local":
            argv = shlex.split(command, posix=os.name != "nt")
        else:
            compute = self.resource.compute
            ssh_alias = (compute.config if compute else {}).get(
                "ssh_alias", config.get("ssh_alias", "spark")
            )
            remote_command = " ".join(shlex.quote(part) for part in shlex.split(command))
            if working_directory:
                remote_command = f"cd {shlex.quote(working_directory)} && {remote_command}"
            argv = ["ssh", "-T", str(ssh_alias), remote_command]
        process = subprocess.Popen(
            argv,
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE,
            text=True,
            bufsize=1,
            cwd=working_directory if transport == "local" else None,
            stdin=subprocess.PIPE,
        )
        assert process.stdin is not None
        process.stdin.write(request.prompt)
        process.stdin.close()
        emitted = False
        assert process.stdout is not None
        for line in process.stdout:
            cleaned = _clean_opencode_output(line)
            if not cleaned:
                continue
            emitted = True
            yield ModelChunk(cleaned + "\n", {"provider": self.provider_name})
        stderr = process.stderr.read().strip() if process.stderr is not None else ""
        return_code = process.wait()
        if return_code != 0:
            raise ProviderError(stderr or "Sol streaming provider failed")
        if not emitted:
            raise ProviderError("Sol streaming provider response missing content")

    def health(self) -> str:
        config = self.resource.config
        try:
            if config.get("transport") == "local":
                command = shlex.split(str(config.get("command", "opencode")), posix=os.name != "nt")[0]
                completed = subprocess.run([command, "--version"], capture_output=True, text=True, timeout=10, check=False)
            else:
                compute = self.resource.compute
                ssh_alias = (compute.config if compute else {}).get("ssh_alias", self.resource.config.get("ssh_alias", "spark"))
                completed = subprocess.run(["ssh", str(ssh_alias), "true"], capture_output=True, text=True, timeout=10, check=False)
        except Exception:
            return "UNAVAILABLE"
        return "AVAILABLE" if completed.returncode == 0 else "UNAVAILABLE"


@dataclass
class QwenProvider:
    resource: Resource
    provider_name: str = "local_inference"

    def complete(self, request: ModelRequestContract) -> ModelResponseContract:
        config = self.resource.config
        url = str(config.get("endpoint_url", "http://localhost:8000/v1/chat/completions"))
        timeout = int(config.get("timeout_seconds", 120))
        attempts = max(1, int(config.get("retry_attempts", 1)))
        backoff = float(config.get("retry_backoff_seconds", 1.0))
        body = {
            "model": config.get("model", self.resource.name),
            "messages": [{"role": "user", "content": request.prompt}],
            "max_tokens": request.token_budget,
            "temperature": config.get("temperature", 0),
        }
        if config.get("response_format"):
            body["response_format"] = config["response_format"]
        if config.get("extra_body"):
            body.update(config["extra_body"])
        failures = []
        for attempt in range(1, attempts + 1):
            http_request = urllib.request.Request(
                url,
                data=json.dumps(body).encode("utf-8"),
                headers={"Content-Type": "application/json"},
                method="POST",
            )
            try:
                with urllib.request.urlopen(http_request, timeout=timeout) as response:
                    data = json.loads(response.read().decode("utf-8"))
                break
            except (urllib.error.HTTPError, urllib.error.URLError, TimeoutError, json.JSONDecodeError) as exc:
                failures.append(f"attempt {attempt}/{attempts}: {exc}")
                if attempt == attempts:
                    raise ProviderError("Qwen provider failed after retries: " + " | ".join(failures)) from exc
                time.sleep(backoff * attempt)
        choices = data.get("choices", [])
        content = ""
        if choices:
            message = choices[0].get("message", {})
            content = message.get("content", "")
        if not isinstance(content, str) or not content:
            raise ProviderError("Qwen provider response missing content")
        return ModelResponseContract(
            model=str(data.get("model", self.resource.name)),
            content=content,
            metadata={
                "provider": self.provider_name,
                "usage": data.get("usage", {}),
                "attempts": len(failures) + 1,
            },
        )

    def stream(self, request: ModelRequestContract) -> Iterator[ModelChunk]:
        config = self.resource.config
        url = str(config.get("endpoint_url", "http://localhost:8000/v1/chat/completions"))
        body = {
            "model": config.get("model", self.resource.name),
            "messages": [{"role": "user", "content": request.prompt}],
            "max_tokens": request.token_budget,
            "temperature": config.get("temperature", 0),
            "stream": True,
            "stream_options": {"include_usage": True},
        }
        if config.get("extra_body"):
            body.update(config["extra_body"])
        http_request = urllib.request.Request(
            url,
            data=json.dumps(body).encode("utf-8"),
            headers={"Content-Type": "application/json"},
            method="POST",
        )
        emitted = False
        usage: dict[str, object] = {}
        with urllib.request.urlopen(
            http_request, timeout=int(config.get("timeout_seconds", 240))
        ) as response:
            for raw_line in response:
                line = raw_line.decode("utf-8").strip()
                if not line.startswith("data:"):
                    continue
                payload = line[5:].strip()
                if payload == "[DONE]":
                    break
                try:
                    event = json.loads(payload)
                except json.JSONDecodeError:
                    continue
                if event.get("usage"):
                    usage = event["usage"]
                    yield ModelChunk("", {"provider": self.provider_name, "usage": usage})
                choices = event.get("choices") or []
                if not choices:
                    continue
                content = (choices[0].get("delta") or {}).get("content")
                if content:
                    emitted = True
                    yield ModelChunk(
                        content,
                        {"provider": self.provider_name, "usage": usage},
                    )
        if not emitted:
            raise ProviderError("Qwen streaming provider response missing content")

    def health(self) -> str:
        base_url = str(self.resource.config.get("health_url", self.resource.config.get("endpoint_url", ""))).replace(
            "/v1/chat/completions", "/health"
        )
        if not base_url:
            return "UNAVAILABLE"
        try:
            with urllib.request.urlopen(base_url, timeout=5) as response:
                return "AVAILABLE" if 200 <= response.status < 500 else "DEGRADED"
        except Exception:
            return "UNAVAILABLE"


def providers_from_resources() -> dict[str, object]:
    providers: dict[str, object] = {}
    opencode_resources = Resource.objects.filter(is_active=True, provider="opencode")
    qwen = Resource.objects.filter(is_active=True, provider="local_inference").first()
    for resource in opencode_resources:
        model_key = str(resource.config.get("model_key") or "").strip().lower()
        if model_key:
            providers[model_key] = SolProvider(resource)
    if "sol" not in providers:
        sol = opencode_resources.first()
        if sol is not None:
            providers["sol"] = SolProvider(sol)
    if qwen is not None:
        providers["qwen"] = QwenProvider(qwen)
    return providers