const RECIPES_URL = "recipes.json";

const state = {
  recipes: [],
  selectedId: null,
  sliderValues: {}, // { [recipeId]: { hydration, doughBalls, doughBallSizeG } }
  markdownCache: {}, // { [recipeId]: htmlString }
};

function escapeHtml(str) {
  return str
    .replace(/&/g, "&")
    .replace(/</g, "&lt;")
    .replace(/>/g, "&gt;");
}

function isSafeUrl(url) {
  if (/["'<>]/.test(url)) return false;
  return /^https?:\/\//i.test(url) || /^[\w./-]+$/.test(url);
}

function inlineMarkdown(text) {
  return escapeHtml(text)
    .replace(/\*\*(.+?)\*\*/g, "<strong>$1</strong>")
    .replace(/!\[([^\]]*)\]\(([^)\s]+)\)/g, (match, alt, url) =>
      isSafeUrl(url) ? `<img src="${url}" alt="${alt}">` : match
    )
    .replace(/\[([^\]]+)\]\(([^)\s]+)\)/g, (match, label, url) =>
      isSafeUrl(url) ? `<a href="${url}" target="_blank" rel="noopener">${label}</a>` : match
    );
}

function markdownToHtml(md) {
  const lines = md.split("\n");
  let html = "";
  let inList = false;

  const closeList = () => {
    if (inList) {
      html += "</ol>";
      inList = false;
    }
  };

  for (const rawLine of lines) {
    const line = rawLine.trim();
    if (!line) {
      closeList();
      continue;
    }
    const headingMatch = line.match(/^(#{1,6})\s+(.*)$/);
    if (headingMatch) {
      closeList();
      const level = Math.min(headingMatch[1].length + 1, 6); // ## -> h3
      html += `<h${level}>${inlineMarkdown(headingMatch[2])}</h${level}>`;
      continue;
    }
    const listMatch = line.match(/^\d+\.\s+(.*)$/);
    if (listMatch) {
      if (!inList) {
        html += "<ol>";
        inList = true;
      }
      html += `<li>${inlineMarkdown(listMatch[1])}</li>`;
      continue;
    }
    closeList();
    html += `<p>${inlineMarkdown(line)}</p>`;
  }
  closeList();
  return html;
}

// Recipes can list more than one flour or water (a poolish has its own), so the
// hydration slider works on the totals and splits them back over the components.
function baseRoleTotal(recipe, role) {
  return recipe.ingredients
    .filter((i) => i.role === role)
    .reduce((sum, i) => sum + i.baseAmount, 0);
}

// Yeast and honey are measured in fractions of a gram, so small amounts keep decimals.
function roundAmount(amount) {
  if (amount >= 10) return Math.round(amount);
  if (amount >= 1) return Math.round(amount * 10) / 10;
  return Math.round(amount * 100) / 100;
}

function computeIngredients(recipe, values) {
  const scaleFactor =
    (values.doughBalls * values.doughBallSizeG) /
    (recipe.baseDoughBalls * recipe.baseDoughBallSizeG);

  const baseFlour = baseRoleTotal(recipe, "flour");
  const baseWater = baseRoleTotal(recipe, "water");
  const flourWaterSum = (baseFlour + baseWater) * scaleFactor;
  const flour = flourWaterSum / (1 + values.hydration / 100);
  const water = flourWaterSum - flour;

  return recipe.ingredients.map((ing) => {
    let amount;
    if (ing.role === "flour") amount = flour * (ing.baseAmount / baseFlour);
    else if (ing.role === "water") amount = water * (ing.baseAmount / baseWater);
    else amount = ing.baseAmount * scaleFactor;
    return { ...ing, amount: roundAmount(amount) };
  });
}

function renderPicker() {
  const nav = document.getElementById("recipe-picker");
  nav.innerHTML = "";
  for (const recipe of state.recipes) {
    const btn = document.createElement("button");
    btn.textContent = recipe.name;
    btn.className = recipe.id === state.selectedId ? "active" : "";
    btn.addEventListener("click", () => selectRecipe(recipe.id));
    nav.appendChild(btn);
  }
}

function baseHydration(recipe) {
  const flour = baseRoleTotal(recipe, "flour");
  const water = baseRoleTotal(recipe, "water");
  return Math.round((water / flour) * 100);
}

async function getInstructionsHtml(recipe) {
  if (state.markdownCache[recipe.id]) return state.markdownCache[recipe.id];
  const res = await fetch(recipe.instructionsFile);
  if (!res.ok) throw new Error(`Failed to load ${recipe.instructionsFile}`);
  const md = await res.text();
  const html = markdownToHtml(md);
  state.markdownCache[recipe.id] = html;
  return html;
}

function renderIngredients(recipe) {
  const values = state.sliderValues[recipe.id];
  const ingredients = computeIngredients(recipe, values);
  const list = ingredients
    .map(
      (ing) =>
        `<li><span>${escapeHtml(ing.name)}</span><span class="amount">${ing.amount}${ing.unit}</span></li>`
    )
    .join("");
  const container = document.getElementById("ingredients-list");
  if (container) container.innerHTML = list;
}

function onSliderChange(recipe) {
  const panel = document.getElementById("recipe-panel");
  const hydrationInput = panel.querySelector("#slider-hydration");
  const ballsInput = panel.querySelector("#slider-balls");
  const sizeInput = panel.querySelector("#slider-size");

  const values = {
    hydration: Number(hydrationInput.value),
    doughBalls: Number(ballsInput.value),
    doughBallSizeG: Number(sizeInput.value),
  };
  state.sliderValues[recipe.id] = values;

  panel.querySelector("#value-hydration").textContent = `${values.hydration}%`;
  panel.querySelector("#value-balls").textContent = values.doughBalls;
  panel.querySelector("#value-size").textContent = `${values.doughBallSizeG}g`;

  renderIngredients(recipe);
}

async function renderRecipePanel(recipe) {
  const panel = document.getElementById("recipe-panel");

  if (!state.sliderValues[recipe.id]) {
    state.sliderValues[recipe.id] = {
      hydration: baseHydration(recipe),
      doughBalls: recipe.baseDoughBalls,
      doughBallSizeG: recipe.baseDoughBallSizeG,
    };
  }
  const values = state.sliderValues[recipe.id];

  panel.innerHTML = `
    <section class="recipe-panel">
      <h2>${escapeHtml(recipe.name)}</h2>
      <p class="recipe-desc">${escapeHtml(recipe.description)}</p>
      <div class="recipe-meta">
        <span>Difficulty: ${escapeHtml(recipe.difficulty)}</span>
        <span>Total time: ${recipe.totalTimeHours}h</span>
      </div>

      <div class="sliders">
        <div class="slider-field">
          <label for="slider-hydration">Hydration <span class="value" id="value-hydration">${values.hydration}%</span></label>
          <input type="range" id="slider-hydration" min="${recipe.hydrationRange.min}" max="${recipe.hydrationRange.max}" value="${values.hydration}">
        </div>
        <div class="slider-field">
          <label for="slider-balls">Dough Balls <span class="value" id="value-balls">${values.doughBalls}</span></label>
          <input type="range" id="slider-balls" min="${recipe.doughBallsRange.min}" max="${recipe.doughBallsRange.max}" value="${values.doughBalls}">
        </div>
        <div class="slider-field">
          <label for="slider-size">Ball Size <span class="value" id="value-size">${values.doughBallSizeG}g</span></label>
          <input type="range" id="slider-size" min="${recipe.doughBallSizeRange.min}" max="${recipe.doughBallSizeRange.max}" step="10" value="${values.doughBallSizeG}">
        </div>
      </div>

      <div class="ingredients">
        <h3>Ingredients</h3>
        <ul id="ingredients-list"></ul>
      </div>

      <div class="instructions" id="instructions">
        <p class="loading">Loading instructions…</p>
      </div>
    </section>
  `;

  ["slider-hydration", "slider-balls", "slider-size"].forEach((id) => {
    panel.querySelector(`#${id}`).addEventListener("input", () => onSliderChange(recipe));
  });

  renderIngredients(recipe);

  try {
    const html = await getInstructionsHtml(recipe);
    const instructionsEl = document.getElementById("instructions");
    if (instructionsEl) instructionsEl.innerHTML = html;
  } catch (err) {
    const instructionsEl = document.getElementById("instructions");
    if (instructionsEl) instructionsEl.innerHTML = `<p class="error">${escapeHtml(err.message)}</p>`;
  }
}

function selectRecipe(id) {
  state.selectedId = id;
  renderPicker();
  const recipe = state.recipes.find((r) => r.id === id);
  renderRecipePanel(recipe);
}

async function init() {
  try {
    const res = await fetch(RECIPES_URL);
    if (!res.ok) throw new Error(`Failed to load ${RECIPES_URL}`);
    state.recipes = await res.json();
    if (state.recipes.length === 0) {
      document.getElementById("recipe-panel").innerHTML = '<p class="error">No recipes found.</p>';
      return;
    }
    selectRecipe(state.recipes[0].id);
  } catch (err) {
    document.getElementById("recipe-panel").innerHTML = `<p class="error">${escapeHtml(err.message)} — this app must be served over http(s), not opened directly as a file.</p>`;
  }
}

init();