"""Provider abstraction for AI CLI tools."""

import os
import shlex
import subprocess
import shutil
from dataclasses import dataclass, field
from pathlib import Path
from typing import Optional, List

import yaml


# Default providers config location
PROVIDERS_FILE = Path.home() / ".smarttools" / "providers.yaml"


@dataclass
class Provider:
    """Definition of an AI provider."""
    name: str
    command: str
    description: str = ""

    def to_dict(self) -> dict:
        return {
            "name": self.name,
            "command": self.command,
            "description": self.description,
        }

    @classmethod
    def from_dict(cls, data: dict) -> "Provider":
        return cls(
            name=data["name"],
            command=data["command"],
            description=data.get("description", ""),
        )


@dataclass
class ProviderResult:
    """Result from a provider call."""
    text: str
    success: bool
    error: Optional[str] = None


# Default providers that come pre-configured
# Profiled with 4-task test: Math, Code, Reasoning, Extract (Dec 2025)
DEFAULT_PROVIDERS = [
    # TOP PICKS - best value/performance ratio
    Provider("opencode-deepseek", "$HOME/.opencode/bin/opencode run --model deepseek/deepseek-chat", "13s 4/4 | BEST VALUE, cheap, fast, accurate"),
    Provider("opencode-pickle", "$HOME/.opencode/bin/opencode run --model opencode/big-pickle", "13s 4/4 | BEST FREE, accurate"),
    Provider("claude-haiku", "claude -p --model haiku", "14s 4/4 | fast, accurate, best paid option"),
    Provider("codex", "codex exec -", "14s 4/4 | reliable, auto-routes"),

    # CLAUDE - all accurate, paid, good for code
    Provider("claude", "claude -p", "18s 4/4 | auto-routes to best model"),
    Provider("claude-opus", "claude -p --model opus", "18s 4/4 | highest quality, expensive"),
    Provider("claude-sonnet", "claude -p --model sonnet", "21s 4/4 | balanced quality/speed"),

    # OPENCODE - additional models
    Provider("opencode-nano", "$HOME/.opencode/bin/opencode run --model opencode/gpt-5-nano", "24s 4/4 | GPT-5 Nano, reliable"),
    Provider("opencode-reasoner", "$HOME/.opencode/bin/opencode run --model deepseek/deepseek-reasoner", "33s 4/4 | complex reasoning, cheap"),
    Provider("opencode-grok", "$HOME/.opencode/bin/opencode run --model opencode/grok-code", "11s 2/4 | fastest but unreliable, FREE"),

    # GEMINI - slow CLI but good for large docs (1M token context)
    Provider("gemini-flash", "gemini --model gemini-2.5-flash", "28s 4/4 | use this for quick tasks"),
    Provider("gemini", "gemini --model gemini-2.5-pro", "91s 3/4 | slow CLI, best for large docs/PDFs"),

    # Mock for testing
    Provider("mock", "mock", "Mock provider for testing"),
]


def get_providers_file() -> Path:
    """Get the providers config file, creating default if needed."""
    if not PROVIDERS_FILE.exists():
        PROVIDERS_FILE.parent.mkdir(parents=True, exist_ok=True)
        save_providers(DEFAULT_PROVIDERS)
    return PROVIDERS_FILE


def load_providers() -> List[Provider]:
    """Load all defined providers."""
    providers_file = get_providers_file()

    try:
        data = yaml.safe_load(providers_file.read_text())
        if not data or "providers" not in data:
            return DEFAULT_PROVIDERS.copy()
        return [Provider.from_dict(p) for p in data["providers"]]
    except Exception:
        return DEFAULT_PROVIDERS.copy()


def save_providers(providers: List[Provider]):
    """Save providers to config file."""
    PROVIDERS_FILE.parent.mkdir(parents=True, exist_ok=True)
    data = {"providers": [p.to_dict() for p in providers]}
    PROVIDERS_FILE.write_text(yaml.dump(data, default_flow_style=False, sort_keys=False))


def get_provider(name: str) -> Optional[Provider]:
    """Get a provider by name."""
    providers = load_providers()
    for p in providers:
        if p.name == name:
            return p
    return None


def add_provider(provider: Provider) -> bool:
    """Add or update a provider."""
    providers = load_providers()

    # Update if exists, otherwise add
    for i, p in enumerate(providers):
        if p.name == provider.name:
            providers[i] = provider
            save_providers(providers)
            return True

    providers.append(provider)
    save_providers(providers)
    return True


def delete_provider(name: str) -> bool:
    """Delete a provider by name."""
    providers = load_providers()
    original_len = len(providers)
    providers = [p for p in providers if p.name != name]

    if len(providers) < original_len:
        save_providers(providers)
        return True
    return False


def call_provider(provider_name: str, prompt: str, timeout: int = 300) -> ProviderResult:
    """
    Call an AI provider with the given prompt.

    Args:
        provider_name: Name of the provider to use
        prompt: The prompt to send
        timeout: Maximum execution time in seconds

    Returns:
        ProviderResult with the response text or error
    """
    # Handle mock provider specially
    if provider_name.lower() == "mock":
        return mock_provider(prompt)

    # Look up provider
    provider = get_provider(provider_name)
    if not provider:
        return ProviderResult(
            text="",
            success=False,
            error=f"Provider '{provider_name}' not found. Use 'smarttools providers' to manage providers."
        )

    # Parse command (expand environment variables)
    cmd = os.path.expandvars(provider.command)

    # Check if base command exists (use shlex for proper quote handling)
    try:
        cmd_parts = shlex.split(cmd)
        base_cmd = cmd_parts[0] if cmd_parts else cmd.split()[0]
    except ValueError:
        # shlex failed (unbalanced quotes, etc.) - fall back to simple split
        base_cmd = cmd.split()[0]

    # Expand ~ for the which check
    base_cmd_expanded = os.path.expanduser(base_cmd)
    if not shutil.which(base_cmd_expanded) and not os.path.isfile(base_cmd_expanded):
        return ProviderResult(
            text="",
            success=False,
            error=f"Command '{base_cmd}' not found. Is it installed and in PATH?\n\nTo install AI providers, run: smarttools providers install"
        )

    try:
        result = subprocess.run(
            cmd,
            shell=True,
            input=prompt,
            capture_output=True,
            text=True,
            timeout=timeout
        )

        if result.returncode != 0:
            error_msg = f"Provider exited with code {result.returncode}: {result.stderr}"
            if "not found" in result.stderr.lower() or "not installed" in result.stderr.lower():
                error_msg += "\n\nTo install AI providers, run: smarttools providers install"
            return ProviderResult(
                text="",
                success=False,
                error=error_msg
            )

        # Warn if output is empty (provider ran but returned nothing)
        if not result.stdout.strip():
            stderr = result.stderr.strip()

            # Check for OpenCode's ProviderModelNotFoundError
            if "ProviderModelNotFoundError" in stderr or "ModelNotFoundError" in stderr:
                # Extract provider and model info if possible
                import re
                provider_match = re.search(r'providerID:\s*"([^"]+)"', stderr)
                model_match = re.search(r'modelID:\s*"([^"]+)"', stderr)
                provider_id = provider_match.group(1) if provider_match else "unknown"
                model_id = model_match.group(1) if model_match else "unknown"

                return ProviderResult(
                    text="",
                    success=False,
                    error=f"Model '{model_id}' from provider '{provider_id}' is not available.\n\n"
                          f"To fix this, either:\n"
                          f"  1. Run 'opencode' to connect the {provider_id} provider\n"
                          f"  2. Use --provider to pick a different model (e.g., --provider opencode-pickle)\n"
                          f"  3. Run 'smarttools ui' to edit the tool's default provider"
                )

            stderr_hint = f" (stderr: {stderr[:200]}...)" if len(stderr) > 200 else (f" (stderr: {stderr})" if stderr else "")
            return ProviderResult(
                text="",
                success=False,
                error=f"Provider returned empty output{stderr_hint}.\n\nThis may mean the model is not available. Try a different provider or run: smarttools providers install"
            )

        return ProviderResult(text=result.stdout, success=True)

    except subprocess.TimeoutExpired:
        return ProviderResult(
            text="",
            success=False,
            error=f"Provider timed out after {timeout} seconds"
        )
    except Exception as e:
        return ProviderResult(
            text="",
            success=False,
            error=f"Provider error: {str(e)}"
        )


def mock_provider(prompt: str) -> ProviderResult:
    """
    Return a mock response for testing.

    Args:
        prompt: The prompt (used for generating mock response)

    Returns:
        ProviderResult with mock response
    """
    lines = prompt.strip().split('\n')
    preview = lines[0][:50] + "..." if len(lines[0]) > 50 else lines[0]

    return ProviderResult(
        text=f"[MOCK RESPONSE]\n"
             f"Prompt length: {len(prompt)} chars, {len(lines)} lines\n"
             f"First line: {preview}\n"
             f"\n"
             f"This is a mock response. Use a real provider for actual output.",
        success=True
    )