document.addEventListener('DOMContentLoaded', () => {
    // DOM Elements
    const form = document.getElementById('analysisForm');
    const companyInput = document.getElementById('ticker');
    const fileInput = document.getElementById('mainReport');
    const fileZone = document.getElementById('mainDropZone'); // This is the <label>
    const submitBtn = document.getElementById('submitBtn');
    const suggestionsList = document.getElementById('ticker-suggestions');
    const readyIndicator = document.getElementById('companyReadyIndicator');

    // Store original content to restore it later
    // We target the first child div which contains the visual elements
    const originalContent = fileZone ? fileZone.firstElementChild.innerHTML : '';

    if (!form || !companyInput || !fileInput || !fileZone || !submitBtn) {
        console.error("Critical elements missing in DOM");
        return;
    }

    // --- Autocomplete Logic ---
    const setupAutocomplete = (inputEl, listEl, indicatorEl, onValidateState) => {
        let debounceTimer;

        inputEl.addEventListener('input', (e) => {
            const query = e.target.value.trim();

            // INVALIDATE on any typing
            onValidateState(false);
            if (indicatorEl) indicatorEl.classList.remove('opacity-100');
            validateForm();

            clearTimeout(debounceTimer);

            if (query.length < 2) {
                hideSuggestions(listEl);
                return;
            }

            debounceTimer = setTimeout(async () => {
                try {
                    const res = await fetch(`/api/search?q=${encodeURIComponent(query)}`);
                    const matches = await res.json();
                    renderSuggestions(matches, inputEl, listEl, indicatorEl, onValidateState);
                } catch (err) {
                    console.error("Search failed", err);
                }
            }, 300);
        });

        // Hide suggestions when clicking outside
        document.addEventListener('click', (e) => {
            if (!inputEl.contains(e.target) && !listEl.contains(e.target)) {
                hideSuggestions(listEl);
            }
        });
    };

    function renderSuggestions(matches, inputEl, listEl, indicatorEl, onValidateState) {
        listEl.innerHTML = '';
        if (!matches || matches.length === 0) {
            hideSuggestions(listEl);
            return;
        }

        matches.forEach(name => {
            const li = document.createElement('li');
            li.className = "px-6 py-3 cursor-pointer hover:bg-white/5 transition-colors text-gray-300 hover:text-primary font-mono text-sm flex items-center gap-2";
            li.innerHTML = `<span class="material-symbols-outlined text-xs opacity-50">show_chart</span> ${name}`;

            li.addEventListener('click', () => {
                inputEl.value = name;

                // VALIDATE on click
                onValidateState(true);
                if (indicatorEl) indicatorEl.classList.add('opacity-100');

                hideSuggestions(listEl);
                validateForm();
            });
            listEl.appendChild(li);
        });

        listEl.classList.remove('hidden');
    }

    function hideSuggestions(listEl) {
        listEl.classList.add('hidden');
    }

    // Main Ticker Setup
    let isTickerValid = false;
    setupAutocomplete(companyInput, suggestionsList, readyIndicator, (isValid) => { isTickerValid = isValid; });

    // --- Dynamic Competitor Logic ---
    const addCompetitorBtn = document.getElementById('addCompetitorBtn');
    const competitorsList = document.getElementById('competitorsList');
    const manualCompetitorsJson = document.getElementById('manualCompetitorsJson');

    // Track validity of each row by ID
    const competitorValidityMap = new Map();

    if (addCompetitorBtn && competitorsList) {
        addCompetitorBtn.addEventListener('click', () => {
            // MAX 3 Limit
            if (competitorsList.children.length >= 5) {
                // Shake button or show toast? Just alert for now or ignore
                return;
            }
            addCompetitorRow();
        });
    }

    function addCompetitorRow() {
        const rowId = 'comp-' + Date.now();
        const row = document.createElement('div');
        row.className = "relative group animate-in fade-in slide-in-from-top-2 duration-300";
        row.id = rowId;

        // Mark as invalid initially if empty, but we treat empty as valid in final check
        // However, if user types, it MUST be valid.
        competitorValidityMap.set(rowId, false);

        row.innerHTML = `
            <input
                class="block py-3 px-0 w-full text-xl md:text-2xl font-mono text-white bg-transparent border-0 border-b-2 border-dashed border-gray-700 appearance-none focus:outline-none focus:ring-0 focus:border-primary peer transition-colors placeholder-transparent tracking-widest pr-10"
                id="input-${rowId}" placeholder=" " type="text" autocomplete="off" />
            <label
                class="peer-focus:font-medium absolute text-xs md:text-sm text-gray-500 duration-300 transform -translate-y-6 scale-75 top-3 -z-10 origin-[0] peer-focus:start-0 peer-focus:text-primary peer-placeholder-shown:scale-100 peer-placeholder-shown:translate-y-0 peer-focus:scale-75 peer-focus:-translate-y-6"
                for="input-${rowId}">
                COMPETITOR ${competitorsList.children.length + 1}
            </label>
            
            <div id="ready-${rowId}"
                class="absolute right-0 bottom-3 opacity-0 transition-opacity flex items-center gap-2 text-primary font-mono text-xs pointer-events-none">
                <span class="material-symbols-outlined text-base">check_circle</span>
            </div>

            <!-- Remove Button (Hover only) -->
            <button type="button" class="absolute -right-8 top-3 text-red-500 opacity-0 group-hover:opacity-100 transition-opacity hover:scale-110" 
                onclick="removeCompetitorRow('${rowId}')">
                <span class="material-symbols-outlined">close</span>
            </button>

            <!-- Autocomplete List -->
            <ul id="list-${rowId}"
                class="absolute z-50 w-full mt-2 bg-surface-dark/95 backdrop-blur-xl border border-white/10 rounded-lg shadow-[0_10px_40px_-10px_rgba(0,0,0,0.8)] hidden max-h-60 overflow-y-auto overflow-x-hidden divide-y divide-white/5 no-scrollbar">
            </ul>
        `;

        competitorsList.appendChild(row);

        const inputEl = row.querySelector('input');
        const listEl = row.querySelector('ul');
        const readyEl = row.querySelector(`#ready-${rowId}`);

        // Attach Autocomplete
        setupAutocomplete(inputEl, listEl, readyEl, (isValid) => {
            competitorValidityMap.set(rowId, isValid);
            updateCompetitorJson(); // Update hidden form field
        });

        // Add focus immediately
        inputEl.focus();
        validateForm();

        // Re-check Max Limit to disable Add button style? (Optional)
    }

    // Global function for onclick to work
    window.removeCompetitorRow = function (rowId) {
        const row = document.getElementById(rowId);
        if (row) {
            row.remove();
            competitorValidityMap.delete(rowId);
            updateCompetitorJson();
            validateForm();
        }
    }

    function updateCompetitorJson() {
        // Collect all VALID inputs
        const names = [];
        competitorsList.querySelectorAll('input').forEach(input => {
            const val = input.value.trim();
            // We assume if it's in the validity map as TRUE, it's a valid ticker
            // But we actually trust the validity map more.
            // However, get the ID from parent
            const rowId = input.parentElement.id;
            if (val.length > 0 && competitorValidityMap.get(rowId)) {
                names.push(val);
            }
        });
        manualCompetitorsJson.value = names.join(',');
    }
    // -----------------------

    // 1. Drag and Drop Logic
    // Prevent default behaviors
    ['dragenter', 'dragover', 'dragleave', 'drop'].forEach(eventName => {
        fileZone.addEventListener(eventName, preventDefaults, false);
        document.body.addEventListener(eventName, preventDefaults, false);
    });

    function preventDefaults(e) {
        e.preventDefault();
        e.stopPropagation();
    }

    // Highlight styles
    ['dragenter', 'dragover'].forEach(eventName => {
        fileZone.addEventListener(eventName, highlight, false);
    });

    ['dragleave', 'drop'].forEach(eventName => {
        fileZone.addEventListener(eventName, unhighlight, false);
    });

    function highlight(e) {
        fileZone.classList.add('border-primary', 'bg-black/40', 'shadow-[inset_0_0_20px_rgba(51,242,13,0.1)]');
        fileZone.classList.remove('bg-black/20');
    }

    function unhighlight(e) {
        fileZone.classList.remove('border-primary', 'bg-black/40', 'shadow-[inset_0_0_20px_rgba(51,242,13,0.1)]');
        fileZone.classList.add('bg-black/20');
    }

    // Handle Drop
    fileZone.addEventListener('drop', (e) => {
        const dt = e.dataTransfer;
        const files = dt.files;
        if (files.length) {
            fileInput.files = files; // Assign files to input
            handleFiles(files);
        }
    });

    // Handle File Input Change (Click selection)
    fileInput.addEventListener('change', function () {
        if (this.files.length) {
            handleFiles(this.files);
        }
    });

    function handleFiles(files) {
        const file = files[0];
        if (file && (file.type === 'application/pdf' || file.name.toLowerCase().endsWith('.pdf'))) {
            updateFileDisplay(file);
        } else {
            alert("Please upload a PDF file only.");
            resetFile();
        }
    }

    function updateFileDisplay(file) {
        const contentDiv = fileZone.firstElementChild;
        if (!contentDiv) return;

        if (file) {
            // Active State
            fileZone.classList.add('border-primary', 'bg-primary/5');
            fileZone.classList.remove('border-gray-700');

            contentDiv.innerHTML = `
                 <div class="flex flex-col items-center justify-center pt-5 pb-6 text-center w-full h-full relative z-20 pointer-events-none">
                    <div class="flex items-center gap-3 text-[#33f20d] font-bold bg-[#33f20d]/10 px-6 py-3 rounded-full border border-[#33f20d]/30 pointer-events-auto">
                        <span class="material-symbols-outlined">description</span>
                        <span class="truncate max-w-[200px]">${file.name}</span>
                        <div id="removeFileBtn" class="ml-2 hover:bg-[#33f20d]/20 rounded-full p-1 transition-colors flex items-center justify-center cursor-pointer">
                            <span class="material-symbols-outlined text-sm text-red-400">close</span>
                        </div>
                    </div>
                    <p class="text-xs text-gray-500 font-mono mt-2">READY TO SCAN</p>
                </div>
            `;

            // Re-attach listener to the new remove button
            // Use setTimeout to ensure DOM is updated
            setTimeout(() => {
                const removeBtn = document.getElementById('removeFileBtn');
                if (removeBtn) {
                    removeBtn.addEventListener('click', (e) => {
                        e.preventDefault();
                        e.stopPropagation(); // Stop bubbling so Label click isn't triggered
                        resetFile();
                    });
                }
            }, 0);

        } else {
            // Default State
            resetUI();
        }
        validateForm();
    }

    function resetFile() {
        fileInput.value = ''; // Clear input
        resetUI();
        validateForm();
    }

    function resetUI() {
        const contentDiv = fileZone.firstElementChild;
        if (!contentDiv) return;

        fileZone.classList.remove('border-primary', 'bg-primary/5');
        fileZone.classList.add('border-gray-700');

        // Restore original HTML content
        contentDiv.innerHTML = originalContent;

        // Ensure "fileInfo" is hidden if it was in the original content
        const fileInfo = document.getElementById('fileInfo');
        if (fileInfo) fileInfo.classList.add('hidden');
    }

    // 2. Validation Logic
    [companyInput, fileInput].forEach(el => {
        // NOTE: We don't use 'input' listener here for companyInput anymore 
        // because we handle it in the debounce logic above, but keeping fileInput checks is fine.
        // Actually, we just need to ensure validateForm is called.
        // It is called in the debounce input handler, so we can leave fileInput here.
        if (el === fileInput) {
            el.addEventListener('change', validateForm);
        }
    });

    function validateForm() {
        // STRICT CHECK: isTickerValid must be true
        const hasCompany = isTickerValid;
        // Check files length
        const hasFile = fileInput.files && fileInput.files.length > 0;

        // Competitor Check (Multi-Row):
        let isCompetitorSafe = true;

        // Iterate all active inputs
        if (competitorsList) {
            const inputs = competitorsList.querySelectorAll('input');
            inputs.forEach(input => {
                const val = input.value.trim();
                const rowId = input.parentElement.id;
                const isValid = competitorValidityMap.get(rowId);

                // If has text, MUST be valid
                if (val.length > 0 && !isValid) {
                    isCompetitorSafe = false;
                }
            });
        }

        if (hasCompany && hasFile && isCompetitorSafe) {
            submitBtn.disabled = false;
            submitBtn.classList.remove('opacity-50', 'cursor-not-allowed');
            submitBtn.classList.add('shadow-neon', 'hover:scale-105');
        } else {
            submitBtn.disabled = true;
            submitBtn.classList.add('opacity-50', 'cursor-not-allowed');
            submitBtn.classList.remove('shadow-neon', 'hover:scale-105');
        }
    }

    // 3. Form Submission
    form.addEventListener('submit', async (e) => {
        e.preventDefault();

        submitBtn.disabled = true;
        const btnContent = submitBtn.querySelector('span'); // The span wrapping text
        const originalBtnHTML = btnContent.innerHTML;

        btnContent.innerHTML = `<span class="material-symbols-outlined animate-spin">refresh</span> UPLOADING...`;

        const formData = new FormData(form);

        try {
            const response = await fetch('/api/analyze', {
                method: 'POST',
                body: formData
            });

            const data = await response.json();

            if (response.ok) {
                window.location.href = `/progress/${data.job_id}`;
            } else {
                alert('Analysis failed: ' + (data.detail || 'Unknown error'));
                submitBtn.disabled = false;
                btnContent.innerHTML = originalBtnHTML;
            }
        } catch (error) {
            console.error(error);
            alert('Server Error. Check console.');
            submitBtn.disabled = false;
            btnContent.innerHTML = originalBtnHTML;
        }
    });

    // Initial check
    validateForm();
});