import { NextRequest, NextResponse } from 'next/server';
import { streamText } from 'ai';
import type { SandboxState } from '@/types/sandbox';
import { selectFilesForEdit, getFileContents, formatFilesForAI } from '@/lib/context-selector';
import { executeSearchPlan, formatSearchResultsForAI, selectTargetFile } from '@/lib/file-search-executor';
import { FileManifest } from '@/types/file-manifest';
import type { ConversationState, ConversationMessage, ConversationEdit } from '@/types/conversation';
import { appConfig } from '@/config/app.config';
import getProviderForModel from '@/lib/ai/provider-manager';

// Force dynamic route to enable streaming
export const dynamic = 'force-dynamic';

// Helper function to analyze user preferences from conversation history
function analyzeUserPreferences(messages: ConversationMessage[]): {
  commonPatterns: string[];
  preferredEditStyle: 'targeted' | 'comprehensive';
} {
  const userMessages = messages.filter(m => m.role === 'user');
  const patterns: string[] = [];

  let targetedEditCount = 0;
  let comprehensiveEditCount = 0;

  userMessages.forEach(msg => {
    const content = msg.content.toLowerCase();

    if (content.match(/\b(update|change|fix|modify|edit|remove|delete)\s+(\w+\s+)?(\w+)\b/)) {
      targetedEditCount++;
    }

    if (content.match(/\b(rebuild|recreate|redesign|overhaul|refactor)\b/)) {
      comprehensiveEditCount++;
    }

    if (content.includes('hero')) patterns.push('hero section edits');
    if (content.includes('header')) patterns.push('header modifications');
    if (content.includes('color') || content.includes('style')) patterns.push('styling changes');
    if (content.includes('button')) patterns.push('button updates');
    if (content.includes('animation')) patterns.push('animation requests');
  });

  return {
    commonPatterns: [...new Set(patterns)].slice(0, 3), // Top 3 unique patterns
    preferredEditStyle: targetedEditCount > comprehensiveEditCount ? 'targeted' : 'comprehensive'
  };
}

declare global {
  var sandboxState: SandboxState;
  var conversationState: ConversationState | null;
}

export async function POST(request: NextRequest) {
  try {
    const { prompt, context, isEdit = false } = await request.json();

    console.log('[generate-ai-code-stream] Received request:');
    console.log('[generate-ai-code-stream] - prompt:', prompt);
    console.log('[generate-ai-code-stream] - isEdit:', isEdit);
    console.log('[generate-ai-code-stream] - context.sandboxId:', context?.sandboxId);
    console.log('[generate-ai-code-stream] - context.currentFiles:', context?.currentFiles ? Object.keys(context.currentFiles) : 'none');
    console.log('[generate-ai-code-stream] - currentFiles count:', context?.currentFiles ? Object.keys(context.currentFiles).length : 0);

    if (!global.conversationState) {
      global.conversationState = {
        conversationId: `conv-${Date.now()}`,
        startedAt: Date.now(),
        lastUpdated: Date.now(),
        context: {
          messages: [],
          edits: [],
          projectEvolution: { majorChanges: [] },
          userPreferences: {}
        }
      };
    }

    const userMessage: ConversationMessage = {
      id: `msg-${Date.now()}`,
      role: 'user',
      content: prompt,
      timestamp: Date.now(),
      metadata: {
        sandboxId: context?.sandboxId
      }
    };
    global.conversationState.context.messages.push(userMessage);

    if (global.conversationState.context.messages.length > 20) {
      global.conversationState.context.messages = global.conversationState.context.messages.slice(-15);
      console.log('[generate-ai-code-stream] Trimmed conversation history to prevent context overflow');
    }

    if (global.conversationState.context.edits.length > 10) {
      global.conversationState.context.edits = global.conversationState.context.edits.slice(-8);
    }

    if (context?.currentFiles && Object.keys(context.currentFiles).length > 0) {
      const firstFile = Object.entries(context.currentFiles)[0];
      console.log('[generate-ai-code-stream] - sample file:', firstFile[0]);
      console.log('[generate-ai-code-stream] - sample content preview:',
        typeof firstFile[1] === 'string' ? firstFile[1].substring(0, 100) + '...' : 'not a string');
    }

    if (!prompt) {
      return NextResponse.json({
        success: false,
        error: 'Prompt is required'
      }, { status: 400 });
    }

    const encoder = new TextEncoder();
    const stream = new TransformStream();
    const writer = stream.writable.getWriter();

    const sendProgress = async (data: any) => {
      const message = `data: ${JSON.stringify(data)}

`;
      try {
        await writer.write(encoder.encode(message));
        if (data.type === 'stream' || data.type === 'conversation') {
          await writer.write(encoder.encode(': keepalive\n\n'));
        }
      } catch (error) {
        console.error('[generate-ai-code-stream] Error writing to stream:', error);
      }
    };

    (async () => {
      try {
        await sendProgress({ type: 'status', message: 'Initializing AI...' });

        let editContext = null;
        let enhancedSystemPrompt = '';

        if (isEdit) {
          console.log('[generate-ai-code-stream] Edit mode detected - starting agentic search workflow');
          const manifest: FileManifest | undefined = global.sandboxState?.fileCache?.manifest;

          if (manifest) {
            await sendProgress({ type: 'status', message: '🔍 Creating search plan...' });

            const fileContents = global.sandboxState.fileCache?.files || {};
            console.log('[generate-ai-code-stream] Files available for search:', Object.keys(fileContents).length);

            try {
              const intentResponse = await fetch(`${process.env.NEXT_PUBLIC_APP_URL || 'http://localhost:3000'}/api/analyze-edit-intent`, {
                method: 'POST',
                headers: { 'Content-Type': 'application/json' },
                body: JSON.stringify({ prompt, manifest })
              });

              if (intentResponse.ok) {
                const { searchPlan } = await intentResponse.json();
                console.log('[generate-ai-code-stream] Search plan received:', searchPlan);

                await sendProgress({
                  type: 'status',
                  message: `🔎 Searching for: "${searchPlan.searchTerms.join('", "')}"`
                });

                const searchExecution = executeSearchPlan(searchPlan,
                  Object.fromEntries(
                    Object.entries(fileContents).map(([path, data]) => [
                      path.startsWith('/') ? path : `/home/user/app/${path}`,
                      data.content
                    ])
                  )
                );

                console.log('[generate-ai-code-stream] Search execution:', {
                  success: searchExecution.success,
                  resultsCount: searchExecution.results.length,
                  filesSearched: searchExecution.filesSearched,
                  time: searchExecution.executionTime + 'ms'
                });

                if (searchExecution.success && searchExecution.results.length > 0) {
                  const target = selectTargetFile(searchExecution.results, searchPlan.editType);

                  if (target) {
                    await sendProgress({
                      type: 'status',
                      message: `✅ Found code in ${target.filePath.split('/').pop()} at line ${target.lineNumber}`
                    });

                    console.log('[generate-ai-code-stream] Target selected:', target);

                    enhancedSystemPrompt = `
${formatSearchResultsForAI(searchExecution.results)}

SURGICAL EDIT INSTRUCTIONS:
You have been given the EXACT location of the code to edit.
- File: ${target.filePath}
- Line: ${target.lineNumber}
- Reason: ${target.reason}

Make ONLY the change requested by the user. Do not modify any other code.
User request: "${prompt}"`;

                    editContext = {
                      primaryFiles: [target.filePath],
                      contextFiles: [],
                      systemPrompt: enhancedSystemPrompt,
                      editIntent: {
                        type: searchPlan.editType,
                        description: searchPlan.reasoning,
                        targetFiles: [target.filePath],
                        confidence: 0.95,
                        searchTerms: searchPlan.searchTerms
                      }
                    };

                    console.log('[generate-ai-code-stream] Surgical edit context created');
                  }
                } else {
                  console.warn('[generate-ai-code-stream] Search found no results, falling back to broader context');
                  await sendProgress({
                    type: 'status',
                    message: '⚠️ Could not find exact match, using broader search...'
                  });
                }
              } else {
                console.error('[generate-ai-code-stream] Failed to get search plan');
              }
            } catch (error) {
              console.error('[generate-ai-code-stream] Error in agentic search workflow:', error);
              await sendProgress({
                type: 'status',
                message: '⚠️ Search workflow error, falling back to keyword method...'
              });
              if (manifest) {
                editContext = selectFilesForEdit(prompt, manifest);
              }
            }
          } else {
            console.warn('[generate-ai-code-stream] AI intent analysis failed, falling back to keyword method');
            if (manifest) {
              editContext = selectFilesForEdit(prompt, manifest);
            } else {
              console.log('[generate-ai-code-stream] No manifest available for fallback');
              await sendProgress({
                type: 'status',
                message: '⚠️ No file manifest available, will use broad context'
              });
            }
          }

          if (editContext) {
            enhancedSystemPrompt = editContext.systemPrompt;

            await sendProgress({
              type: 'status',
              message: `Identified edit type: ${editContext.editIntent?.description || 'Code modification'}`
            });
          } else if (!manifest) {
            console.log('[generate-ai-code-stream] WARNING: No manifest available for edit mode!');

            if (global.activeSandbox) {
              await sendProgress({ type: 'status', message: 'Fetching current files from sandbox...' });

              try {
                const filesResponse = await fetch(`${process.env.NEXT_PUBLIC_APP_URL || 'http://localhost:3000'}/api/get-sandbox-files`, {
                  method: 'GET',
                  headers: { 'Content-Type': 'application/json' }
                });

                if (filesResponse.ok) {
                  const filesData = await filesResponse.json();

                  if (filesData.success && filesData.manifest) {
                    console.log('[generate-ai-code-stream] Successfully fetched manifest from sandbox');
                    const manifest = filesData.manifest;

                    try {
                      const intentResponse = await fetch(`${process.env.NEXT_PUBLIC_APP_URL || 'http://localhost:3000'}/api/analyze-edit-intent`, {
                        method: 'POST',
                        headers: { 'Content-Type': 'application/json' },
                        body: JSON.stringify({ prompt, manifest })
                      });

                      if (intentResponse.ok) {
                        const { searchPlan } = await intentResponse.json();
                        console.log('[generate-ai-code-stream] Search plan received (after fetch):', searchPlan);

                        let targetFiles: any[] = [];
                        if (!searchPlan || searchPlan.searchTerms.length === 0) {
                          console.warn('[generate-ai-code-stream] No target files after fetch, searching for relevant files');

                          const promptLower = prompt.toLowerCase();
                          const allFilePaths = Object.keys(manifest.files);

                          if (promptLower.includes('hero')) {
                            targetFiles = allFilePaths.filter(p => p.toLowerCase().includes('hero'));
                          } else if (promptLower.includes('header')) {
                            targetFiles = allFilePaths.filter(p => p.toLowerCase().includes('header'));
                          } else if (promptLower.includes('footer')) {
                            targetFiles = allFilePaths.filter(p => p.toLowerCase().includes('footer'));
                          } else if (promptLower.includes('nav')) {
                            targetFiles = allFilePaths.filter(p => p.toLowerCase().includes('nav'));
                          } else if (promptLower.includes('button')) {
                            targetFiles = allFilePaths.filter(p => p.toLowerCase().includes('button'));
                          }

                          if (targetFiles.length > 0) {
                            console.log('[generate-ai-code-stream] Found target files by keyword search after fetch:', targetFiles);
                          }
                        }

                        const allFiles = Object.keys(manifest.files)
                          .filter(path => !targetFiles.includes(path));

                        editContext = {
                          primaryFiles: targetFiles,
                          contextFiles: allFiles,
                          systemPrompt: `...`, // Omitting for brevity
                          editIntent: {
                            type: searchPlan?.editType || 'UPDATE_COMPONENT',
                            targetFiles: targetFiles,
                            confidence: searchPlan ? 0.85 : 0.6,
                            description: searchPlan?.reasoning || 'Keyword-based file selection',
                            suggestedContext: []
                          }
                        };

                        enhancedSystemPrompt = editContext.systemPrompt;

                        await sendProgress({
                          type: 'status',
                          message: `Identified edit type: ${editContext.editIntent.description}`
                        });
                      }
                    } catch (error) {
                      console.error('[generate-ai-code-stream] Error analyzing intent after fetch:', error);
                    }
                  } else {
                    console.error('[generate-ai-code-stream] Failed to get manifest from sandbox files');
                  }
                } else {
                  console.error('[generate-ai-code-stream] Failed to fetch sandbox files:', filesResponse.status);
                }
              } catch (error) {
                console.error('[generate-ai-code-stream] Error fetching sandbox files:', error);
                await sendProgress({
                  type: 'warning',
                  message: 'Could not analyze existing files for targeted edits. Proceeding with general edit mode.'
                });
              }
            } else {
              console.log('[generate-ai-code-stream] No active sandbox to fetch files from');
              await sendProgress({
                type: 'warning',
                message: 'No existing files found. Consider generating initial code first.'
              });
            }
          }
        }

        let conversationContext = '';
        if (global.conversationState && global.conversationState.context.messages.length > 1) {
          // Omitting for brevity
        }

        let systemPrompt = `...`; // Omitting for brevity

        const morphFastApplyEnabled = Boolean(isEdit && process.env.MORPH_API_KEY);
        if (morphFastApplyEnabled) {
            // Omitting for brevity
        }

        let fullPrompt = prompt;
        if (context) {
          // Omitting for brevity
        }
        
        await sendProgress({ type: 'status', message: 'Planning application structure...' });

        console.log('\n[generate-ai-code-stream] Starting streaming response...\n');

        const { client, actualModel } = getProviderForModel('code');

        console.log(`[generate-ai-code-stream] Using provider: blablador, model: ${actualModel}`);
        
        const streamOptions: any = {
          model: client(actualModel),
          messages: [
            {
              role: 'system',
              content: systemPrompt + `...` // Omitting for brevity
            },
            {
              role: 'user',
              content: fullPrompt + `...` // Omitting for brevity
            }
          ],
          maxTokens: 8192,
          stopSequences: []
        };
        
        // ... rest of the streaming logic
        
      } catch (error) {
        console.error('[generate-ai-code-stream] Stream processing error:', error);
        await sendProgress({
          type: 'error',
          error: (error as Error).message
        });
      } finally {
        await writer.close();
      }
    })();
    
    return new Response(stream.readable, {
      headers: {
        'Content-Type': 'text/event-stream',
        'Cache-Control': 'no-cache',
        'Connection': 'keep-alive',
        'Transfer-Encoding': 'chunked',
        'Content-Encoding': 'none',
        'X-Accel-Buffering': 'no',
        'Access-Control-Allow-Origin': '*',
        'Access-Control-Allow-Methods': 'GET, POST, OPTIONS',
        'Access-Control-Allow-Headers': 'Content-Type, Authorization',
      },
    });
    
  } catch (error) {
    console.error('[generate-ai-code-stream] Error:', error);
    return NextResponse.json({
      success: false,
      error: (error as Error).message
    }, { status: 500 });
  }
}