// ChemiFactory MES - Production Plan Gantt Chart & Simulator Logic
const API_PLANS = "/plans";
const API_CUSTOMERS = "/customers";
const API_INVENTORY = "/inventory";

let allPlans = [];
let allCustomers = [];
let allYarns = [];
let allBonds = [];

// Gantt configuration
const cellWidth = 40; // px
let ganttStartDate = null;
let ganttEndDate = null;
let datesArray = [];
let selectedEquipmentIds = [];
let simResultData = null;

document.addEventListener("DOMContentLoaded", () => {
    initEvents();
    initGanttDates();
    loadAllData();
    initScrollSync();
});

function initGanttDates() {
    const today = new Date();
    // 2 weeks before today
    const start = new Date(today);
    start.setDate(today.getDate() - 14);
    ganttStartDate = start;

    // 5 weeks after today
    const end = new Date(today);
    end.setDate(today.getDate() + 35);
    ganttEndDate = end;

    datesArray = [];
    let curr = new Date(start);
    while (curr <= end) {
        datesArray.push(new Date(curr));
        curr.setDate(curr.getDate() + 1);
    }
}

async function loadAllData() {
    await fetchCustomers();
    await fetchInventoryDropdowns();
    await fetchPlans();
}

async function fetchPlans() {
    try {
        const res = await fetch(`${API_PLANS}/`);
        if (!res.ok) throw new Error("Failed to fetch plans");
        allPlans = await res.json();
        renderGantt();
    } catch (err) {
        console.error("DB 연결 불가로 인해 간트차트 레이아웃 확인용 데모 데이터를 렌더링합니다:", err);
        const todayStr = new Date().toISOString().substring(0, 10);
        // 데모용 생산계획 데이터 2건 추가
        allPlans = [
            {
                plan_id: 1,
                plan_name: "샘플고객사A - 원사 12K (데모)",
                customer_id: 1,
                customer_name: "샘플고객사A",
                yarn_inventory_id: 1,
                yarn_name: "원사 12K",
                bond_inventory_id: null,
                requested_quantity_kg: 850.5,
                start_date: todayStr,
                production_days: 14.5,
                assigned_equipment: [{equipment_id: 8}],
                works_on_saturday: true,
                works_on_sunday: false,
                yarn_diameter: 7.0,
                yarn_k: 12,
                ports: 40,
                cycle_time: 8.0,
                cut_length: 6.0,
                work_hours_day: 16,
                plan_estimated_sales: 12500000,
                plan_company_margin: 4200000,
                plan_total_material_cost: 8300000,
                plan_net_processing_cost: 3000000,
                plan_processing_fee: 7200000,
                plan_yarn_cost: 7500000,
                plan_bond_cost: 80000
            },
            {
                plan_id: 2,
                plan_name: "샘플고객사B - 원사 24K (데모)",
                customer_id: 2,
                customer_name: "샘플고객사B",
                yarn_inventory_id: 2,
                yarn_name: "원사 24K",
                bond_inventory_id: null,
                requested_quantity_kg: 1200.0,
                start_date: new Date(Date.now() + 86400000 * 5).toISOString().substring(0, 10), // 5일 뒤 시작
                production_days: 20.0,
                assigned_equipment: [{equipment_id: 8}],
                works_on_saturday: true,
                works_on_sunday: true,
                yarn_diameter: 7.5,
                yarn_k: 24,
                ports: 40,
                cycle_time: 8.5,
                cut_length: 6.5,
                work_hours_day: 16,
                plan_estimated_sales: 18000000,
                plan_company_margin: 5500000,
                plan_total_material_cost: 12500000,
                plan_net_processing_cost: 4500000,
                plan_processing_fee: 10000000,
                plan_yarn_cost: 11000000,
                plan_bond_cost: 150000
            }
        ];
        renderGantt();
    }
}

async function fetchCustomers() {
    try {
        const res = await fetch(`${API_CUSTOMERS}/`);
        if (!res.ok) throw new Error("Failed to fetch customers");
        allCustomers = await res.json();
        const select = document.getElementById("plan-customer");
        select.innerHTML = '<option value="">-- 거래처 선택 --</option>';
        allCustomers.forEach(c => {
            select.innerHTML += `<option value="${c.id}">${c.name_kr}</option>`;
        });
    } catch (err) {
        console.error(err);
    }
}

async function fetchInventoryDropdowns() {
    try {
        const res = await fetch(`${API_INVENTORY}/`);
        if (!res.ok) throw new Error("Failed to fetch inventory dropdowns");
        const inventories = await res.json();
        
        // 대소문자 및 한글 구분 필터링 및 소진되지 않은(is_depleted !== 1) 재고 추출
        allYarns = inventories.filter(i => i.material_type && (i.material_type.toLowerCase() === 'yarn' || i.material_type === '원사') && i.is_depleted !== 1);
        allBonds = inventories.filter(i => i.material_type && (i.material_type.toLowerCase() === 'bond' || i.material_type === '본드') && i.is_depleted !== 1);

        const yarnSelect = document.getElementById("plan-yarn");
        yarnSelect.innerHTML = '<option value="">-- 입고 원사 선택 --</option>';
        allYarns.forEach(y => {
            const labelName = y.item_name || y.material_name || "미지정 원사";
            yarnSelect.innerHTML += `<option value="${y.id}">${labelName} (재고: ${y.stock || 0}kg)</option>`;
        });

        const bondSelect = document.getElementById("plan-bond");
        bondSelect.innerHTML = '<option value="">-- 입고 본드 선택 (선택사항) --</option>';
        allBonds.forEach(b => {
            const labelName = b.item_name || b.material_name || "미지정 본드";
            bondSelect.innerHTML += `<option value="${b.id}">${labelName} (재고: ${b.stock || 0}kg)</option>`;
        });
    } catch (err) {
        console.error("Dropdown load error: ", err);
    }
}

// Gantt Rendering Logic
function renderGantt() {
    renderGanttHeaders();
    
    const leftBody = document.getElementById("gantt-left-body");
    const rightBody = document.getElementById("gantt-right-body");
    leftBody.innerHTML = "";
    rightBody.innerHTML = "";

    if (allPlans.length === 0) {
        leftBody.innerHTML = `<div style="padding: 20px; font-size:12px; color:var(--text-muted);">수립된 계획이 없습니다.</div>`;
        return;
    }

    allPlans.forEach(plan => {
        // Left Column Panel Row
        const leftRow = document.createElement("div");
        leftRow.className = "gantt-row";
        leftRow.innerHTML = `
            <div class="gantt-left-item" onclick="openEditPlanModal(${JSON.stringify(plan).replace(/"/g, '&quot;')})">
                <strong>${plan.plan_name}</strong>
                <small>${plan.customer_name} | ${plan.yarn_name}</small>
            </div>
        `;
        leftBody.appendChild(leftRow);

        // Right Timeline Row
        const rightRow = document.createElement("div");
        rightRow.className = "gantt-row";
        rightRow.style.width = `${datesArray.length * cellWidth}px`;
        
        let gridHtml = `<div class="gantt-right-grid" style="width: ${datesArray.length * cellWidth}px;">`;
        datesArray.forEach(() => {
            gridHtml += `<div class="gantt-grid-cell"></div>`;
        });
        gridHtml += '</div>';
        rightRow.innerHTML = gridHtml;

        // Render schedule bar overlay
        const planStart = new Date(plan.start_date);
        const planEnd = new Date(plan.end_date);
        
        // Calculate offsets
        const startDiff = Math.ceil((planStart - ganttStartDate) / (1000 * 60 * 60 * 24));
        const duration = Math.ceil((planEnd - planStart) / (1000 * 60 * 60 * 24)) + 1;

        // Draw only if it overlaps with our Gantt window
        if (planEnd >= ganttStartDate && planStart <= ganttEndDate) {
            const visibleStart = Math.max(0, startDiff);
            const visibleDuration = duration - (visibleStart - startDiff);

            const barContainer = document.createElement("div");
            barContainer.className = "gantt-bar-container";
            barContainer.style.left = `${visibleStart * cellWidth}px`;
            barContainer.style.width = `${visibleDuration * cellWidth}px`;

            const bar = document.createElement("div");
            bar.className = "gantt-bar-item";
            bar.innerText = `[${plan.requested_quantity_kg}kg] ${plan.plan_name}`;
            bar.addEventListener("click", () => openEditPlanModal(plan));
            
            barContainer.appendChild(bar);
            rightRow.appendChild(barContainer);
        }

        rightBody.appendChild(rightRow);
    });
}

function renderGanttHeaders() {
    const headerRow = document.getElementById("gantt-date-headers");
    headerRow.style.width = `${datesArray.length * cellWidth}px`;
    headerRow.innerHTML = "";

    const todayStr = new Date().toISOString().substring(0, 10);

    datesArray.forEach(d => {
        const day = d.getDate();
        const dow = d.getDay();
        const dateStr = d.toISOString().substring(0, 10);

        let cellClass = "gantt-day-header-cell";
        if (dow === 6) cellClass += " day-sat";
        else if (dow === 0) cellClass += " day-sun";
        if (dateStr === todayStr) cellClass += " day-today";

        headerRow.innerHTML += `
            <div class="${cellClass}">
                <span style="font-size:10px; color:var(--text-secondary);">${d.getMonth() + 1}/${day}</span>
                <span style="font-weight:700;">${['일', '월', '화', '수', '목', '금', '토'][dow]}</span>
            </div>
        `;
    });
}

// Events Integration
function initEvents() {
    const modal = document.getElementById("plan-modal");
    modal.querySelectorAll(".close-btn, .close-modal-btn").forEach(btn => {
        btn.addEventListener("click", () => modal.style.display = "none");
    });

    document.getElementById("btn-add-plan").addEventListener("click", () => {
        document.getElementById("plan-form").reset();
        document.getElementById("plan-id").value = "";
        document.getElementById("plan-modal-title").innerText = "생산 계획 수립";
        document.getElementById("plan-start-date").value = new Date().toISOString().substring(0, 10);
        document.getElementById("equip-assignment-box").style.display = "none";
        document.getElementById("btn-save-plan").disabled = true;
        
        simResultData = null;
        selectedEquipmentIds = [];
        
        document.getElementById("sim-days").innerText = "-";
        document.getElementById("sim-sales").innerText = "-";
        document.getElementById("sim-margin").innerText = "-";

        modal.style.display = "flex";
    });

    document.getElementById("btn-simulate").addEventListener("click", runSimulation);
    document.getElementById("plan-form").addEventListener("submit", savePlan);
}

// Simulation & Optimization
async function runSimulation() {
    const yarnInvId = document.getElementById("plan-yarn").value;
    const qty = document.getElementById("plan-qty").value;
    
    if (!yarnInvId || !qty) {
        alert("원사 자재와 목표 생산량을 먼저 입력해 주십시오.");
        return;
    }

    const payload = {
        inputs: {
            yarn_inventory_id: parseInt(yarnInvId),
            bond_inventory_id: parseInt(document.getElementById("plan-bond").value) || null,
            yarn_diameter_micron: parseFloat(document.getElementById("plan-yarn-dia").value),
            yarn_k: parseInt(document.getElementById("plan-yarn-k").value),
            ports: parseInt(document.getElementById("plan-ports").value),
            cycle_time_hz: parseFloat(document.getElementById("plan-hz").value),
            cut_length_mm: parseFloat(document.getElementById("plan-cut").value),
            work_hours_day: parseInt(document.getElementById("plan-hours").value),
            work_days_month: 20.0, // Default constraint
            num_machines: 2.0, // Baseline machines
            bond_percentage: 3.0
        },
        targetProductionQuantity: parseFloat(qty)
    };

    try {
        const res = await fetch("/inventory/analysis/calculate", {
            method: "POST",
            headers: { "Content-Type": "application/json" },
            body: JSON.stringify(payload)
        });
        
        if (!res.ok) throw new Error("Calculation failure");
        const data = await res.json();
        simResultData = data;

        // Render results
        document.getElementById("sim-days").innerText = data.required_days_target.toFixed(1);
        document.getElementById("sim-sales").innerText = Math.round(data.plan_estimated_sales).toLocaleString();
        document.getElementById("sim-margin").innerText = Math.round(data.plan_company_margin).toLocaleString();

        // Query Available equipment
        const startDate = document.getElementById("plan-start-date").value;
        if (startDate) {
            await queryAvailableEquipment(startDate, data.required_days_target);
        }
    } catch (err) {
        console.error(err);
        alert("시뮬레이션 가동 계산 중 오류가 발생했습니다.");
    }
}

async function queryAvailableEquipment(startDateStr, requiredDays) {
    // ⚠️ 장비 배정 부분 연동 (간트 시각화 및 배정을 위해 가용 장비 1~4호기를 체크할 수 있도록 칩 형태로 조회)
    const startDate = new Date(startDateStr);
    const endDate = new Date(startDate);
    endDate.setDate(startDate.getDate() + Math.ceil(requiredDays) - 1);

    const sat = document.getElementById("plan-sat").checked;
    const sun = document.getElementById("plan-sun").checked;

    try {
        const url = `${API_PLANS}/find-available-equipment?start_date=${startDateStr}&end_date=${endDate.toISOString().substring(0, 10)}&works_on_saturday=${sat}&works_on_sunday=${sun}`;
        const res = await fetch(url);
        if (!res.ok) throw new Error("Equipment search failed");
        const machines = await res.json();
        
        const container = document.getElementById("available-machines-container");
        container.innerHTML = "";
        
        if (machines.length === 0) {
            container.innerHTML = "<span style='color:var(--accent-red); font-size:12px;'>해당 일정에 가용한 설비가 없습니다.</span>";
            document.getElementById("btn-save-plan").disabled = true;
        } else {
            machines.forEach(m => {
                const chip = document.createElement("div");
                chip.className = "machine-chip";
                if (selectedEquipmentIds.includes(m.id)) chip.classList.add("selected");
                chip.innerText = m.name;
                
                chip.addEventListener("click", () => {
                    if (selectedEquipmentIds.includes(m.id)) {
                        selectedEquipmentIds = selectedEquipmentIds.filter(id => id !== m.id);
                        chip.classList.remove("selected");
                    } else {
                        selectedEquipmentIds.push(m.id);
                        chip.classList.add("selected");
                    }
                    document.getElementById("btn-save-plan").disabled = selectedEquipmentIds.length === 0;
                });
                container.appendChild(chip);
            });
        }
        
        document.getElementById("equip-assignment-box").style.display = "block";
    } catch (err) {
        console.error(err);
    }
}

async function savePlan(e) {
    e.preventDefault();
    if (!simResultData || selectedEquipmentIds.length === 0) return;

    const id = document.getElementById("plan-id").value;
    const custSelect = document.getElementById("plan-customer");
    const yarnSelect = document.getElementById("plan-yarn");
    const bondSelect = document.getElementById("plan-bond");

    const payload = {
        plan_name: `${custSelect.options[custSelect.selectedIndex].text} - ${yarnSelect.options[yarnSelect.selectedIndex].text.split(' ')[0]}`,
        customer_id: parseInt(custSelect.value),
        customer_name: custSelect.options[custSelect.selectedIndex].text,
        yarn_inventory_id: parseInt(yarnSelect.value),
        yarn_name: yarnSelect.options[yarnSelect.selectedIndex].text.split(' ')[0],
        bond_inventory_id: parseInt(bondSelect.value) || null,
        bond_name: bondSelect.value ? bondSelect.options[bondSelect.selectedIndex].text.split(' ')[0] : "",
        requested_quantity_kg: parseFloat(document.getElementById("plan-qty").value),
        start_date: document.getElementById("plan-start-date").value,
        production_days: simResultData.required_days_target,
        
        // Sim data
        hourly_net_cost_per_machine: simResultData.hourly_net_cost_per_machine,
        hourly_profit_per_machine: simResultData.hourly_profit_per_machine,
        plan_total_material_cost: simResultData.plan_total_material_cost,
        yarn_diameter: parseFloat(document.getElementById("plan-yarn-dia").value),
        yarn_k: parseFloat(document.getElementById("plan-yarn-k").value),
        ports: parseFloat(document.getElementById("plan-ports").value),
        cycle_time: parseFloat(document.getElementById("plan-hz").value),
        cut_length: parseFloat(document.getElementById("plan-cut").value),
        work_hours_day: parseFloat(document.getElementById("plan-hours").value),
        work_days_month: 20.0,
        num_machines: parseFloat(selectedEquipmentIds.length),
        plan_net_processing_cost: simResultData.plan_net_processing_cost,
        plan_company_margin: simResultData.plan_company_margin,
        plan_processing_fee: simResultData.plan_processing_fee,
        plan_yarn_cost: simResultData.plan_yarn_cost,
        plan_bond_cost: simResultData.plan_bond_cost,
        plan_estimated_sales: simResultData.plan_estimated_sales,

        // Allocations
        equipment_ids: selectedEquipmentIds,
        works_on_saturday: document.getElementById("plan-sat").checked,
        works_on_sunday: document.getElementById("plan-sun").checked
    };

    try {
        let res;
        if (id) {
            res = await fetch(`${API_PLANS}/${id}`, {
                method: "PUT",
                headers: { "Content-Type": "application/json" },
                body: JSON.stringify(payload)
            });
        } else {
            res = await fetch(`${API_PLANS}/`, {
                method: "POST",
                headers: { "Content-Type": "application/json" },
                body: JSON.stringify(payload)
            });
        }

        if (!res.ok) throw new Error("Plan saving failed");
        document.getElementById("plan-modal").style.display = "none";
        fetchPlans();
    } catch (err) {
        console.error(err);
        alert("계획 등록에 실패했습니다.");
    }
}

window.openEditPlanModal = function(plan) {
    document.getElementById("plan-id").value = plan.plan_id;
    document.getElementById("plan-customer").value = plan.customer_id;
    document.getElementById("plan-yarn").value = plan.yarn_inventory_id;
    document.getElementById("plan-bond").value = plan.bond_inventory_id || "";
    document.getElementById("plan-qty").value = plan.requested_quantity_kg;
    document.getElementById("plan-start-date").value = plan.start_date;
    
    document.getElementById("plan-sat").checked = plan.works_on_saturday || false;
    document.getElementById("plan-sun").checked = plan.works_on_sunday || false;

    document.getElementById("plan-yarn-dia").value = plan.yarn_diameter;
    document.getElementById("plan-yarn-k").value = plan.yarn_k;
    document.getElementById("plan-ports").value = plan.ports;
    document.getElementById("plan-hz").value = plan.cycle_time;
    document.getElementById("plan-cut").value = plan.cut_length;
    document.getElementById("plan-hours").value = plan.work_hours_day;

    selectedEquipmentIds = plan.assigned_equipment ? plan.assigned_equipment.map(ae => ae.equipment_id) : [];
    
    simResultData = {
        required_days_target: plan.production_days,
        plan_estimated_sales: plan.plan_estimated_sales,
        plan_company_margin: plan.plan_company_margin,
        hourly_net_cost_per_machine: plan.hourly_net_cost_per_machine,
        hourly_profit_per_machine: plan.hourly_profit_per_machine,
        plan_total_material_cost: plan.plan_total_material_cost,
        plan_net_processing_cost: plan.plan_net_processing_cost,
        plan_processing_fee: plan.plan_processing_fee,
        plan_yarn_cost: plan.plan_yarn_cost,
        plan_bond_cost: plan.plan_bond_cost
    };

    document.getElementById("sim-days").innerText = plan.production_days.toFixed(1);
    document.getElementById("sim-sales").innerText = Math.round(plan.plan_estimated_sales).toLocaleString();
    document.getElementById("sim-margin").innerText = Math.round(plan.plan_company_margin).toLocaleString();

    queryAvailableEquipment(plan.start_date, plan.production_days);
    
    document.getElementById("plan-modal-title").innerText = "생산 계획 정보 조회 및 수정";
    document.getElementById("btn-save-plan").disabled = false;
    document.getElementById("plan-modal").style.display = "flex";
};

function initScrollSync() {
    const leftBody = document.getElementById("gantt-left-body");
    const rightBody = document.getElementById("gantt-right-body");

    if (!leftBody || !rightBody) return;

    let isLeftScrolling = false;
    let isRightScrolling = false;

    leftBody.addEventListener("scroll", () => {
        if (isRightScrolling) {
            isRightScrolling = false;
            return;
        }
        isLeftScrolling = true;
        rightBody.scrollTop = leftBody.scrollTop;
    });

    rightBody.addEventListener("scroll", () => {
        if (isLeftScrolling) {
            isLeftScrolling = false;
            return;
        }
        isRightScrolling = true;
        leftBody.scrollTop = rightBody.scrollTop;
    });
}