import {
  LanguageModelV3Prompt,
  UnsupportedFunctionalityError,
} from '@ai-sdk/provider';
import { GroqChatPrompt } from './groq-api-types';
import { convertToBase64 } from '@ai-sdk/provider-utils';

export function convertToGroqChatMessages(
  prompt: LanguageModelV3Prompt,
): GroqChatPrompt {
  const messages: GroqChatPrompt = [];

  for (const { role, content } of prompt) {
    switch (role) {
      case 'system': {
        messages.push({ role: 'system', content });
        break;
      }

      case 'user': {
        if (content.length === 1 && content[0].type === 'text') {
          messages.push({ role: 'user', content: content[0].text });
          break;
        }

        messages.push({
          role: 'user',
          content: content.map(part => {
            switch (part.type) {
              case 'text': {
                return { type: 'text', text: part.text };
              }
              case 'file': {
                if (!part.mediaType.startsWith('image/')) {
                  throw new UnsupportedFunctionalityError({
                    functionality: 'Non-image file content parts',
                  });
                }

                const mediaType =
                  part.mediaType === 'image/*' ? 'image/jpeg' : part.mediaType;

                return {
                  type: 'image_url',
                  image_url: {
                    url:
                      part.data instanceof URL
                        ? part.data.toString()
                        : `data:${mediaType};base64,${convertToBase64(part.data)}`,
                  },
                };
              }
            }
          }),
        });

        break;
      }

      case 'assistant': {
        let text = '';
        let reasoning = '';
        const toolCalls: Array<{
          id: string;
          type: 'function';
          function: { name: string; arguments: string };
        }> = [];

        for (const part of content) {
          switch (part.type) {
            // groq supports reasoning for tool-calls in multi-turn conversations
            // https://github.com/vercel/ai/issues/7860
            case 'reasoning': {
              reasoning += part.text;
              break;
            }

            case 'text': {
              text += part.text;
              break;
            }

            case 'tool-call': {
              toolCalls.push({
                id: part.toolCallId,
                type: 'function',
                function: {
                  name: part.toolName,
                  arguments: JSON.stringify(part.input),
                },
              });
              break;
            }
          }
        }

        messages.push({
          role: 'assistant',
          content: text,
          ...(reasoning.length > 0 ? { reasoning } : null),
          ...(toolCalls.length > 0 ? { tool_calls: toolCalls } : null),
        });

        break;
      }

      case 'tool': {
        for (const toolResponse of content) {
          if (toolResponse.type === 'tool-approval-response') {
            continue;
          }
          const output = toolResponse.output;

          let contentValue: string;
          switch (output.type) {
            case 'text':
            case 'error-text':
              contentValue = output.value;
              break;
            case 'execution-denied':
              contentValue = output.reason ?? 'Tool execution denied.';
              break;
            case 'content':
            case 'json':
            case 'error-json':
              contentValue = JSON.stringify(output.value);
              break;
          }

          messages.push({
            role: 'tool',
            tool_call_id: toolResponse.toolCallId,
            content: contentValue,
          });
        }
        break;
      }

      default: {
        const _exhaustiveCheck: never = role;
        throw new Error(`Unsupported role: ${_exhaustiveCheck}`);
      }
    }
  }

  return messages;
}