/**
 * Main Application Logic
 * Orchestrates API calls and UI updates
 */

class CVSRepositoryBrowser {
    constructor() {
        this.currentFile = null;
        this.currentHistory = null;
        this.initialize();
    }

    /**
     * Initialize the application
     */
    async initialize() {
        try {
            // Check API health
            await this.checkHealth();
            
            // Load initial repository tree
            await this.loadTree();
            
            // Setup event listeners
            this.setupEventListeners();
            
            ui.updateStatus('Connected', 'connected');
        } catch (error) {
            console.error('Initialization error:', error);
            ui.updateStatus('Connection Error', 'error');
        }
    }

    /**
     * Check API health
     */
    async checkHealth() {
        try {
            const health = await api.getHealth();
            console.log('API Health:', health);
            return health;
        } catch (error) {
            throw new Error('Failed to connect to API');
        }
    }

    /**
     * Load repository tree
     */
    async loadTree() {
        try {
            ui.treeContainer.innerHTML = '<div class="loading">Loading repository...</div>';
            const files = await api.getTree();
            ui.buildTree(files, (filePath) => this.loadFile(filePath));
        } catch (error) {
            console.error('Error loading tree:', error);
            ui.treeContainer.innerHTML = `<div class="loading" style="color: #991b1b;">Error loading repository: ${error.message}</div>`;
        }
    }

    /**
     * Load file content
     * @param {string} filePath - Path to the file
     * @param {string} revision - Optional specific revision
     */
    async loadFile(filePath, revision = null) {
        try {
            this.currentFile = filePath;
            ui.showLoading('Loading file...');
            
            const content = await api.getFileContent(filePath, revision);
            ui.displayFile(filePath, content);
            
            // Load history for this file
            await this.loadFileHistory(filePath);
        } catch (error) {
            console.error('Error loading file:', error);
            ui.showError(`Error loading file: ${error.message}`);
        }
    }

    /**
     * Load file at specific revision
     * @param {string} filePath - Path to the file
     * @param {string} revision - Specific revision
     */
    async loadFileAtRevision(filePath, revision) {
        try {
            await this.loadFile(filePath, revision);
            ui.showView(ui.fileView);
        } catch (error) {
            console.error('Error loading file at revision:', error);
            ui.showError(`Error loading file: ${error.message}`);
        }
    }

    /**
     * Load file history
     * @param {string} filePath - Path to the file
     */
    async loadFileHistory(filePath) {
        try {
            const history = await api.getFileHistory(filePath);
            this.currentHistory = history;
            ui.populateRevisionSelectors(history);
        } catch (error) {
            console.error('Error loading history:', error);
        }
    }

    /**
     * Show file history view
     */
    async showHistory() {
        if (!this.currentFile) return;
        
        try {
            ui.showLoading('Loading history...');
            const history = await api.getFileHistory(this.currentFile);
            ui.displayHistory(history);
        } catch (error) {
            console.error('Error showing history:', error);
            ui.showError(`Error loading history: ${error.message}`);
        }
    }

    /**
     * Show diff view
     */
    showDiffView() {
        if (!this.currentFile || !this.currentHistory) return;
        ui.populateRevisionSelectors(this.currentHistory);
        ui.showView(ui.diffView);
    }

    /**
     * Generate and display diff
     */
    async generateDiff() {
        if (!this.currentFile) return;
        
        const rev1 = ui.rev1Select.value;
        const rev2 = ui.rev2Select.value;
        
        if (!rev1 || !rev2) {
            ui.showError('Please select two revisions');
            return;
        }

        try {
            ui.diffContent.innerHTML = '<div class="loading">Generating diff...</div>';
            const diffResult = await api.getDiff(this.currentFile, rev1, rev2);
            const diffText = diffResult.diff || diffResult;
            ui.displayDiff(diffText);
        } catch (error) {
            console.error('Error generating diff:', error);
            ui.showError(`Error generating diff: ${error.message}`);
        }
    }

    /**
     * Show diff for a history item (comparing with previous revision)
     * @param {string} filePath - Path to the file
     * @param {string} currentRevision - Current revision
     * @param {string} previousRevision - Previous revision (or null if this is the first)
     */
    async showHistoryItemDiff(filePath, currentRevision, previousRevision) {
        if (!filePath) return;

        try {
            ui.diffContent.innerHTML = '<div class="loading">Generating diff...</div>';
            
            if (!previousRevision) {
                // If there's no previous revision, show a message
                ui.diffContent.innerHTML = '<div class="loading">This is the first revision - no previous version to compare</div>';
                ui.showView(ui.diffView);
                return;
            }

            // Generate diff between previous and current revision
            const diffResult = await api.getDiff(filePath, previousRevision, currentRevision);
            const diffText = diffResult.diff || diffResult;
            ui.displayDiff(diffText);
        } catch (error) {
            console.error('Error generating history item diff:', error);
            ui.diffContent.innerHTML = `<div class="loading" style="color: #991b1b;">Error generating diff: ${error.message}</div>`;
            ui.showView(ui.diffView);
        }
    }

    /**
     * Show patchsets view
     */
    async showPatchsets() {
        try {
            ui.patchsetContent.innerHTML = '<div class="loading">Loading patchsets...</div>';
            const patchsets = await api.getPatchsets();
            ui.displayPatchsets(patchsets);
        } catch (error) {
            console.error('Error showing patchsets:', error);
            ui.patchsetContent.innerHTML = `<div class="loading" style="color: #991b1b;">Error loading patchsets: ${error.message}</div>`;
            ui.showView(ui.patchsetView);
        }
    }

    /**
     * Show patchset diff
     * @param {string} patchset - Patchset number
     */
    async showPatchsetDiff(patchset) {
        try {
            ui.patchsetDiffContent.innerHTML = '<div class="loading">Loading patchset diff...</div>';
            const diffResult = await api.getPatchsetDiff(patchset);
            const diffText = diffResult.diff || diffResult;
            ui.displayPatchsetDiff(diffText);
        } catch (error) {
            console.error('Error showing patchset diff:', error);
            ui.patchsetDiffContent.innerHTML = `<div class="loading" style="color: #991b1b;">Error loading patchset diff: ${error.message}</div>`;
            ui.showView(ui.patchsetDiffView);
        }
    }

    /**
     * Setup event listeners
     */
    setupEventListeners() {
        // File view buttons
        ui.historyBtn.addEventListener('click', () => this.showHistory());
        ui.diffBtn.addEventListener('click', () => this.showDiffView());

        // History view back button
        ui.backFromHistoryBtn.addEventListener('click', () => {
            ui.showView(ui.fileView);
        });

        // Diff view buttons
        ui.generateDiffBtn.addEventListener('click', () => this.generateDiff());
        ui.backFromDiffBtn.addEventListener('click', () => {
            ui.showView(ui.fileView);
        });

        // Patchset view buttons
        ui.patchsetsBtn.addEventListener('click', () => this.showPatchsets());
        ui.backFromPatchsetBtn.addEventListener('click', () => {
            ui.showView(ui.welcomeView);
        });

        // Patchset diff view back button
        ui.backFromPatchsetDiffBtn.addEventListener('click', () => {
            ui.showView(ui.patchsetView);
        });
    }
}

// Initialize application when DOM is ready
document.addEventListener('DOMContentLoaded', () => {
    window.app = new CVSRepositoryBrowser();
});