import { PROVIDERS, OAUTH_ENDPOINTS } from "../config/constants.js";

// Token expiry buffer (refresh if expires within 5 minutes)
export const TOKEN_EXPIRY_BUFFER_MS = 5 * 60 * 1000;

/**
 * Refresh OAuth access token using refresh token
 */
export async function refreshAccessToken(provider, refreshToken, credentials, log) {
  const config = PROVIDERS[provider];
  
  if (!config || !config.refreshUrl) {
    log?.warn?.("TOKEN_REFRESH", `No refresh URL configured for provider: ${provider}`);
    return null;
  }

  if (!refreshToken) {
    log?.warn?.("TOKEN_REFRESH", `No refresh token available for provider: ${provider}`);
    return null;
  }

  try {
    const response = await fetch(config.refreshUrl, {
      method: "POST",
      headers: {
        "Content-Type": "application/x-www-form-urlencoded",
        Accept: "application/json",
      },
      body: new URLSearchParams({
        grant_type: "refresh_token",
        refresh_token: refreshToken,
        client_id: config.clientId,
        client_secret: config.clientSecret,
      }),
    });

    if (!response.ok) {
      const errorText = await response.text();
      log?.error?.("TOKEN_REFRESH", `Failed to refresh token for ${provider}`, {
        status: response.status,
        error: errorText,
      });
      return null;
    }

    const tokens = await response.json();
    
    log?.info?.("TOKEN_REFRESH", `Successfully refreshed token for ${provider}`, {
      hasNewAccessToken: !!tokens.access_token,
      hasNewRefreshToken: !!tokens.refresh_token,
      expiresIn: tokens.expires_in,
    });

    return {
      accessToken: tokens.access_token,
      refreshToken: tokens.refresh_token || refreshToken,
      expiresIn: tokens.expires_in,
    };
  } catch (error) {
    log?.error?.("TOKEN_REFRESH", `Error refreshing token for ${provider}`, {
      error: error.message,
    });
    return null;
  }
}

/**
 * Specialized refresh for Claude OAuth tokens
 */
export async function refreshClaudeOAuthToken(refreshToken, log) {
  const response = await fetch(OAUTH_ENDPOINTS.anthropic.token, {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      Accept: "application/json",
    },
    body: JSON.stringify({
      grant_type: "refresh_token",
      refresh_token: refreshToken,
      client_id: PROVIDERS.claude.clientId,
    }),
  });

  if (!response.ok) {
    const errorText = await response.text();
    log?.error?.("TOKEN_REFRESH", "Failed to refresh Claude OAuth token", {
      status: response.status,
      error: errorText,
    });
    return null;
  }

  const tokens = await response.json();
  
  log?.info?.("TOKEN_REFRESH", "Successfully refreshed Claude OAuth token", {
    hasNewAccessToken: !!tokens.access_token,
    hasNewRefreshToken: !!tokens.refresh_token,
    expiresIn: tokens.expires_in,
  });

  return {
    accessToken: tokens.access_token,
    refreshToken: tokens.refresh_token || refreshToken,
    expiresIn: tokens.expires_in,
  };
}

/**
 * Specialized refresh for Google providers (Gemini, Antigravity)
 */
export async function refreshGoogleToken(refreshToken, clientId, clientSecret, log) {
  const response = await fetch(OAUTH_ENDPOINTS.google.token, {
    method: "POST",
    headers: {
      "Content-Type": "application/x-www-form-urlencoded",
      Accept: "application/json",
    },
    body: new URLSearchParams({
      grant_type: "refresh_token",
      refresh_token: refreshToken,
      client_id: clientId,
      client_secret: clientSecret,
    }),
  });

  if (!response.ok) {
    const errorText = await response.text();
    log?.error?.("TOKEN_REFRESH", "Failed to refresh Google token", {
      status: response.status,
      error: errorText,
    });
    return null;
  }

  const tokens = await response.json();
  
  log?.info?.("TOKEN_REFRESH", "Successfully refreshed Google token", {
    hasNewAccessToken: !!tokens.access_token,
    hasNewRefreshToken: !!tokens.refresh_token,
    expiresIn: tokens.expires_in,
  });

  return {
    accessToken: tokens.access_token,
    refreshToken: tokens.refresh_token || refreshToken,
    expiresIn: tokens.expires_in,
  };
}

/**
 * Specialized refresh for Qwen OAuth tokens
 */
export async function refreshQwenToken(refreshToken, log) {
  const endpoint = OAUTH_ENDPOINTS.qwen.token;
  
  try {
    const response = await fetch(endpoint, {
      method: "POST",
      headers: {
        "Content-Type": "application/x-www-form-urlencoded",
        Accept: "application/json",
      },
      body: new URLSearchParams({
        grant_type: "refresh_token",
        refresh_token: refreshToken,
        client_id: PROVIDERS.qwen.clientId,
      }),
    });

    if (response.status === 200) {
      const tokens = await response.json();
      
      log?.info?.("TOKEN_REFRESH", "Successfully refreshed Qwen token", {
        hasNewAccessToken: !!tokens.access_token,
        hasNewRefreshToken: !!tokens.refresh_token,
        expiresIn: tokens.expires_in,
      });

      return {
        accessToken: tokens.access_token,
        refreshToken: tokens.refresh_token || refreshToken,
        expiresIn: tokens.expires_in,
      };
    } else {
      const errorText = await response.text().catch(() => "");
      log?.warn?.("TOKEN_REFRESH", `Error with Qwen endpoint`, {
        status: response.status,
        error: errorText,
      });
    }
  } catch (error) {
    log?.warn?.("TOKEN_REFRESH", `Network error trying Qwen endpoint`, {
      error: error.message,
    });
  }

  log?.error?.("TOKEN_REFRESH", "Failed to refresh Qwen token");
  return null;
}

/**
 * Specialized refresh for Codex (OpenAI) OAuth tokens
 */
export async function refreshCodexToken(refreshToken, log) {
  const response = await fetch(OAUTH_ENDPOINTS.openai.token, {
    method: "POST",
    headers: {
      "Content-Type": "application/x-www-form-urlencoded",
      Accept: "application/json",
    },
    body: new URLSearchParams({
      grant_type: "refresh_token",
      refresh_token: refreshToken,
      client_id: PROVIDERS.codex.clientId,
      scope: "openid profile email offline_access",
    }),
  });

  if (!response.ok) {
    const errorText = await response.text();
    log?.error?.("TOKEN_REFRESH", "Failed to refresh Codex token", {
      status: response.status,
      error: errorText,
    });
    return null;
  }

  const tokens = await response.json();
  
  log?.info?.("TOKEN_REFRESH", "Successfully refreshed Codex token", {
    hasNewAccessToken: !!tokens.access_token,
    hasNewRefreshToken: !!tokens.refresh_token,
    expiresIn: tokens.expires_in,
  });

  return {
    accessToken: tokens.access_token,
    refreshToken: tokens.refresh_token || refreshToken,
    expiresIn: tokens.expires_in,
  };
}

/**
 * Specialized refresh for Kiro (AWS CodeWhisperer) tokens
 * Supports both AWS SSO OIDC (Builder ID/IDC) and Social Auth (Google/GitHub)
 */
export async function refreshKiroToken(refreshToken, providerSpecificData, log) {
  const authMethod = providerSpecificData?.authMethod;
  const clientId = providerSpecificData?.clientId;
  const clientSecret = providerSpecificData?.clientSecret;
  const region = providerSpecificData?.region;
  
  // AWS SSO OIDC (Builder ID or IDC)
  // If clientId and clientSecret exist, assume AWS SSO OIDC (default to builder-id if authMethod not specified)
  if (clientId && clientSecret) {
    const isIDC = authMethod === "idc";
    const endpoint = isIDC && region
      ? `https://oidc.${region}.amazonaws.com/token`
      : "https://oidc.us-east-1.amazonaws.com/token";
      
    const response = await fetch(endpoint, {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
        Accept: "application/json",
      },
      body: JSON.stringify({
        clientId: clientId,
        clientSecret: clientSecret,
        refreshToken: refreshToken,
        grantType: "refresh_token",
      }),
    });

    if (!response.ok) {
      const errorText = await response.text();
      log?.error?.("TOKEN_REFRESH", "Failed to refresh Kiro AWS token", {
        status: response.status,
        error: errorText,
      });
      return null;
    }

    const tokens = await response.json();
    
    log?.info?.("TOKEN_REFRESH", "Successfully refreshed Kiro AWS token", {
      hasNewAccessToken: !!tokens.accessToken,
      expiresIn: tokens.expiresIn,
    });

    return {
      accessToken: tokens.accessToken,
      refreshToken: tokens.refreshToken || refreshToken,
      expiresIn: tokens.expiresIn,
    };
  }
  
  // Social Auth (Google/GitHub) - use Kiro's refresh endpoint
  const response = await fetch(PROVIDERS.kiro.tokenUrl, {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      Accept: "application/json",
    },
    body: JSON.stringify({
      refreshToken: refreshToken,
    }),
  });

  if (!response.ok) {
    const errorText = await response.text();
    log?.error?.("TOKEN_REFRESH", "Failed to refresh Kiro social token", {
      status: response.status,
      error: errorText,
    });
    return null;
  }

  const tokens = await response.json();
  
  log?.info?.("TOKEN_REFRESH", "Successfully refreshed Kiro social token", {
    hasNewAccessToken: !!tokens.accessToken,
    expiresIn: tokens.expiresIn,
  });

  return {
    accessToken: tokens.accessToken,
    refreshToken: tokens.refreshToken || refreshToken,
    expiresIn: tokens.expiresIn,
  };
}

/**
 * Specialized refresh for iFlow OAuth tokens
 */
export async function refreshIflowToken(refreshToken, log) {
  const basicAuth = btoa(`${PROVIDERS.iflow.clientId}:${PROVIDERS.iflow.clientSecret}`);
  
  const response = await fetch(OAUTH_ENDPOINTS.iflow.token, {
    method: "POST",
    headers: {
      "Content-Type": "application/x-www-form-urlencoded",
      Accept: "application/json",
      Authorization: `Basic ${basicAuth}`,
    },
    body: new URLSearchParams({
      grant_type: "refresh_token",
      refresh_token: refreshToken,
      client_id: PROVIDERS.iflow.clientId,
      client_secret: PROVIDERS.iflow.clientSecret,
    }),
  });

  if (!response.ok) {
    const errorText = await response.text();
    log?.error?.("TOKEN_REFRESH", "Failed to refresh iFlow token", {
      status: response.status,
      error: errorText,
    });
    return null;
  }

  const tokens = await response.json();
  
  log?.info?.("TOKEN_REFRESH", "Successfully refreshed iFlow token", {
    hasNewAccessToken: !!tokens.access_token,
    hasNewRefreshToken: !!tokens.refresh_token,
    expiresIn: tokens.expires_in,
  });

  return {
    accessToken: tokens.access_token,
    refreshToken: tokens.refresh_token || refreshToken,
    expiresIn: tokens.expires_in,
  };
}

/**
 * Specialized refresh for GitHub Copilot OAuth tokens
 */
export async function refreshGitHubToken(refreshToken, log) {
  const response = await fetch(OAUTH_ENDPOINTS.github.token, {
    method: "POST",
    headers: {
      "Content-Type": "application/x-www-form-urlencoded",
      Accept: "application/json",
    },
    body: new URLSearchParams({
      grant_type: "refresh_token",
      refresh_token: refreshToken,
      client_id: PROVIDERS.github.clientId,
      client_secret: PROVIDERS.github.clientSecret,
    }),
  });

  if (!response.ok) {
    const errorText = await response.text();
    log?.error?.("TOKEN_REFRESH", "Failed to refresh GitHub token", {
      status: response.status,
      error: errorText,
    });
    return null;
  }

  const tokens = await response.json();
  
  log?.info?.("TOKEN_REFRESH", "Successfully refreshed GitHub token", {
    hasNewAccessToken: !!tokens.access_token,
    hasNewRefreshToken: !!tokens.refresh_token,
    expiresIn: tokens.expires_in,
  });

  return {
    accessToken: tokens.access_token,
    refreshToken: tokens.refresh_token || refreshToken,
    expiresIn: tokens.expires_in,
  };
}

/**
 * Refresh GitHub Copilot token using GitHub access token
 */
export async function refreshCopilotToken(githubAccessToken, log) {
  try {
    const response = await fetch("https://api.github.com/copilot_internal/v2/token", {
      headers: {
        "Authorization": `Bearer ${githubAccessToken}`,
        "User-Agent": "GitHub-Copilot/1.0",
        "Accept": "*/*"
      }
    });

    if (!response.ok) {
      const errorText = await response.text();
      log?.error?.("TOKEN_REFRESH", "Failed to refresh Copilot token", {
        status: response.status,
        error: errorText
      });
      return null;
    }

    const data = await response.json();
    
    log?.info?.("TOKEN_REFRESH", "Successfully refreshed Copilot token", {
      hasToken: !!data.token,
      expiresAt: data.expires_at
    });

    return {
      token: data.token,
      expiresAt: data.expires_at
    };
  } catch (error) {
    log?.error?.("TOKEN_REFRESH", "Error refreshing Copilot token", {
      error: error.message
    });
    return null;
  }
}

/**
 * Get access token for a specific provider
 */
export async function getAccessToken(provider, credentials, log) {
  if (!credentials || !credentials.refreshToken) {
    log?.warn?.("TOKEN_REFRESH", `No refresh token available for provider: ${provider}`);
    return null;
  }

  switch (provider) {
    case "gemini":
    case "gemini-cli":
    case "antigravity":
      return await refreshGoogleToken(
        credentials.refreshToken,
        PROVIDERS[provider].clientId,
        PROVIDERS[provider].clientSecret,
        log
      );
    
    case "claude":
      return await refreshClaudeOAuthToken(credentials.refreshToken, log);
    
    case "codex":
      return await refreshCodexToken(credentials.refreshToken, log);
    
    case "qwen":
      return await refreshQwenToken(credentials.refreshToken, log);
    
    case "iflow":
      return await refreshIflowToken(credentials.refreshToken, log);
    
    case "github":
      return await refreshGitHubToken(credentials.refreshToken, log);
    
    default:
      log?.warn?.("TOKEN_REFRESH", `Unsupported provider for token refresh: ${provider}`);
      return null;
  }
}

/**
 * Refresh token by provider type (helper for handlers)
 */
export async function refreshTokenByProvider(provider, credentials, log) {
  if (!credentials.refreshToken) return null;

  switch (provider) {
    case "gemini-cli":
    case "antigravity":
      return refreshGoogleToken(
        credentials.refreshToken,
        PROVIDERS[provider].clientId,
        PROVIDERS[provider].clientSecret,
        log
      );
    case "claude":
      return refreshClaudeOAuthToken(credentials.refreshToken, log);
    case "codex":
      return refreshCodexToken(credentials.refreshToken, log);
    case "qwen":
      return refreshQwenToken(credentials.refreshToken, log);
    case "iflow":
      return refreshIflowToken(credentials.refreshToken, log);
    case "github":
      return refreshGitHubToken(credentials.refreshToken, log);
    default:
      return refreshAccessToken(provider, credentials.refreshToken, credentials, log);
  }
}

/**
 * Format credentials for provider
 */
export function formatProviderCredentials(provider, credentials, log) {
  const config = PROVIDERS[provider];
  if (!config) {
    log?.warn?.("TOKEN_REFRESH", `No configuration found for provider: ${provider}`);
    return null;
  }

  switch (provider) {
    case "gemini":
      return {
        apiKey: credentials.apiKey,
        accessToken: credentials.accessToken,
        projectId: credentials.projectId
      };
    
    case "claude":
      return {
        apiKey: credentials.apiKey,
        accessToken: credentials.accessToken
      };
    
    case "codex":
    case "qwen":
    case "iflow":
    case "openai":
    case "openrouter":
      return {
        apiKey: credentials.apiKey,
        accessToken: credentials.accessToken
      };
    
    case "antigravity":
    case "gemini-cli":
      return {
        accessToken: credentials.accessToken,
        refreshToken: credentials.refreshToken
      };
    
    default:
      return {
        apiKey: credentials.apiKey,
        accessToken: credentials.accessToken,
        refreshToken: credentials.refreshToken
      };
  }
}

/**
 * Get all access tokens for a user
 */
export async function getAllAccessTokens(userInfo, log) {
  const results = {};
  
  if (userInfo.connections && Array.isArray(userInfo.connections)) {
    for (const connection of userInfo.connections) {
      if (connection.isActive && connection.provider) {
        const token = await getAccessToken(connection.provider, {
          refreshToken: connection.refreshToken
        }, log);
        
        if (token) {
          results[connection.provider] = token;
        }
      }
    }
  }
  
  return results;
}

/**
 * Refresh token with retry and exponential backoff
 * Retries on failure with increasing delay: 1s, 2s, 3s...
 * @param {function} refreshFn - Async function that returns token or null
 * @param {number} maxRetries - Max retry attempts (default 3)
 * @param {object} log - Logger instance (optional)
 * @returns {Promise<object|null>} Token result or null if all retries fail
 */
export async function refreshWithRetry(refreshFn, maxRetries = 3, log = null) {
  for (let attempt = 0; attempt < maxRetries; attempt++) {
    if (attempt > 0) {
      const delay = attempt * 1000;
      log?.debug?.("TOKEN_REFRESH", `Retry ${attempt}/${maxRetries} after ${delay}ms`);
      await new Promise(r => setTimeout(r, delay));
    }

    try {
      const result = await refreshFn();
      if (result) return result;
    } catch (error) {
      log?.warn?.("TOKEN_REFRESH", `Attempt ${attempt + 1}/${maxRetries} failed: ${error.message}`);
    }
  }

  log?.error?.("TOKEN_REFRESH", `All ${maxRetries} retry attempts failed`);
  return null;
}