const fs = require("fs");
const path = require("path");
const betterSqlite3 = require("better-sqlite3");
const { LRUCache } = require("lru-cache");
const { Eta } = require("eta");
const cheerio = require("cheerio");

const db = betterSqlite3("./dbs/0.sqlite");

db.pragma("journal_mode = WAL");

function applyMigrations() {
  db.exec(`
        CREATE TABLE IF NOT EXISTS migrations (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            filename TEXT NOT NULL,
            applied_at DATETIME DEFAULT CURRENT_TIMESTAMP
        );
    `);

  const migrationsDir = path.join(__dirname, "/migrations");
  const migrationFiles = fs
    .readdirSync(migrationsDir)
    .filter((file) => file.endsWith(".sql"));

  migrationFiles.forEach((file) => {
    const isApplied = db
      .prepare("SELECT filename FROM migrations WHERE filename = ?")
      .get(file);

    if (!isApplied) {
      const sql = fs.readFileSync(path.join(migrationsDir, file), "utf-8");
      db.exec(sql);
      db.prepare("INSERT INTO migrations (filename) VALUES (?)").run(file);
      console.log(`Migration applied: ${file}`);
    }
  });
}

// __   __  _______  _______  ______
// |  | |  ||       ||       ||    _ |
// |  | |  ||  _____||    ___||   | ||
// |  |_|  || |_____ |   |___ |   |_||_
// |       ||_____  ||    ___||    __  |
// |       | _____| ||   |___ |   |  | |
// |_______||_______||_______||___|  |_|

function createUser(username, hashedPassword) {
  return db
    .prepare("INSERT INTO users (username, password) VALUES (?, ?)")
    .run(username, hashedPassword).lastInsertRowid;
}

function getUser(username) {
  return db.prepare("SELECT * from users where username = ?").get(username);
}

function getUserById(id) {
  return db.prepare("SELECT id, username FROM users WHERE id = ?").get(id);
}

// _     _  _______  ______    ___   _  _______  __   __  _______  _______
// | | _ | ||       ||    _ |  |   | | ||       ||  | |  ||       ||       |
// | || || ||   _   ||   | ||  |   |_| ||  _____||  |_|  ||   _   ||    _  |
// |       ||  | |  ||   |_||_ |      _|| |_____ |       ||  | |  ||   |_| |
// |       ||  |_|  ||    __  ||     |_ |_____  ||       ||  |_|  ||    ___|
// |   _   ||       ||   |  | ||    _  | _____| ||   _   ||       ||   |
// |__| |__||_______||___|  |_||___| |_||_______||__| |__||_______||___|

const dbCache = new LRUCache({ max: 25 });

function getDbInstance(dbId) {
  let dbInstance = dbCache.get(dbId);

  if (!dbInstance) {
    dbInstance = betterSqlite3(`dbs/${dbId}.sqlite`);
    dbInstance.pragma("journal_mode = WAL");
    dbCache.set(dbId, dbInstance);
  }

  return dbInstance;
}

function getAllRoutes() {
  return db
    .prepare(
      `
    SELECT routes.*, structures.route_prefix
    FROM routes
    JOIN structures ON routes.structure_id = structures.id
    ORDER BY routes.updated_at DESC;
  `,
    )
    .all();
}

const templateCache = new LRUCache({ max: 100 });

function annotateTemplateHtml(html, template) {
  function annotate($, element) {
    const current = $(element).attr("data-bliss-templates");
    let templates = [];
    if (current) {
      try {
        templates = JSON.parse(current);
      } catch (_) {}
    }
    if (!templates.some((item) => String(item.id) === String(template.id))) {
      templates.push({ id: String(template.id), name: template.name });
    }
    $(element).attr("data-bliss-templates", JSON.stringify(templates));
    if (!$(element).attr("data-bliss-template-id")) {
      $(element).attr({
        "data-bliss-template-id": String(template.id),
        "data-bliss-template-name": template.name,
      });
    }
  }
  const lower = html.trimStart().toLowerCase();
  if (lower.startsWith("<html") || lower.startsWith("<!doctype")) {
    const $ = cheerio.load(html);
    annotate($, $("body")[0]);
    return $.html();
  }
  const $ = cheerio.load(html, null, false);
  for (const child of $.root().children()) annotate($, child);
  return $.html();
}

function getTemplater(structId) {
  let etaInstance = templateCache.get(structId);

  if (!etaInstance) {
    etaInstance = new Eta({});
    etaInstance.resolvePath = function (path, _) {
      return path;
    };
    etaInstance.readFile = function (templateAlias) {
      return getTemplateContentByName(structId, templateAlias).content;
    };
    const etaRender = etaInstance.render;
    etaInstance.render = function (templateName, data, meta) {
      const html = etaRender.call(this, templateName, data, meta);
      if (typeof templateName !== "string") return html;
      const template = getTemplateByName(structId, templateName);
      return template ? annotateTemplateHtml(html, template) : html;
    };
    templateCache.set(structId, etaInstance);
  }

  return etaInstance;
}

function getStructures() {
  return db.prepare("SELECT * from structures").all();
}

function getStructure(id) {
  return db.prepare("SELECT * from structures where ID = ?").get(id);
}

function createStructure(name, userId) {
  const stmt = db.prepare(
    "INSERT INTO structures (name, user_id) VALUES (?, ?)",
  );
  const info = stmt.run(name, userId);
  return info.lastInsertRowid; // Returns the structure_id of the newly created structure
}

function createRoute(verb, path, structureId, handler) {
  path = encodeURI(path);

  const stmt = db.prepare(
    "INSERT INTO routes (verb, path, structure_id, handler) VALUES (?, ?, ?, ?)"
  );
  const info = stmt.run(verb, path, structureId, handler);
  const routeId = info.lastInsertRowid; // Get the newly created route ID

  if (verb !== 'GET') {
    createScaffoldPage(routeId);
  }

  recordVersion("route", routeId, structureId, { verb, path, handler });

  return routeId; // Returns the route_id of the newly created route
}

const ROUTE_SELECT = `
  SELECT
    r.*,
    s.route_prefix,
    sp.id AS scaffold_page_id,
    sp.content AS scaffold_page_content,
    sp2.id AS scaffold_params_id,
    sp2.query_params,
    sp2.url_params
  FROM routes r
  LEFT JOIN scaffold_pages sp ON r.id = sp.route_id
  LEFT JOIN scaffold_params sp2 ON r.id = sp2.route_id
  LEFT JOIN structures s ON r.structure_id = s.id
`;

function getRoutes(structureId) {
  return db
    .prepare(`${ROUTE_SELECT} WHERE r.structure_id = ? ORDER BY sp.created_at DESC, sp2.created_at DESC`)
    .all(structureId);
}

function getRoute(routeId) {
  return db
    .prepare(`${ROUTE_SELECT} WHERE r.id = ? ORDER BY sp.created_at DESC, sp2.created_at DESC LIMIT 1`)
    .get(routeId);
}

// Update `fields` of a row by id from a plain object. Returns the run info.
function update(table, fields, obj) {
  const placeholders = fields.map((field) => `${field} = ?`).join(", ");
  const values = fields.map((field) => obj[field]);
  values.push(obj.id);
  return db.prepare(`UPDATE ${table} SET ${placeholders} WHERE id = ?`).run(...values);
}

// ---- version history (append-only) --------------------------------------
//
// Snapshot the code-bearing fields of a route/template/db every time they
// change, so nothing a user (or the plumber) edits is ever truly lost. Deduped
// against the latest snapshot for that entity, so no-op saves, error-flag-only
// route writes, and server-restart WS re-bootstraps don't pile up noise.
// snapshotFor() defines exactly which fields are versioned per type; keep the
// key order stable so the dedup string compare is reliable.
function snapshotFor(entityType, obj) {
  switch (entityType) {
    case "route":
      return { verb: obj.verb, path: obj.path, handler: obj.handler };
    case "template":
      return { name: obj.name, content: obj.content, test_object: obj.test_object };
    case "db":
      return { name: obj.name, library: obj.library };
    default:
      throw new Error(`unknown version entity type: ${entityType}`);
  }
}

function recordVersion(entityType, entityId, structureId, obj) {
  const json = JSON.stringify(snapshotFor(entityType, obj));
  const last = db
    .prepare(
      "SELECT snapshot FROM versions WHERE entity_type = ? AND entity_id = ? ORDER BY id DESC LIMIT 1",
    )
    .get(entityType, entityId);
  if (last && last.snapshot === json) return; // content unchanged — skip
  db.prepare(
    "INSERT INTO versions (entity_type, entity_id, structure_id, snapshot) VALUES (?, ?, ?, ?)",
  ).run(entityType, entityId, structureId, json);
}

// Version list for one entity (newest first). Omits the snapshot body to stay
// scannable; fetch a single version to get its full content.
function getVersions(entityType, entityId) {
  return db
    .prepare(
      `SELECT id, entity_type, entity_id, structure_id, created_at, length(snapshot) AS bytes
       FROM versions WHERE entity_type = ? AND entity_id = ? ORDER BY id DESC`,
    )
    .all(entityType, entityId);
}

// One version with its full snapshot parsed back into fields.
function getVersion(versionId) {
  const row = db.prepare("SELECT * FROM versions WHERE id = ?").get(versionId);
  if (!row) return null;
  return { ...row, snapshot: JSON.parse(row.snapshot) };
}

function updateRoute(route) {
  update("routes", ["verb", "path", "structure_id", "handler", "updated_at", "error"], route);
  recordVersion("route", route.id, route.structure_id, route);
}

function updateDb(appDb) {
  update("dbs", ["name", "library"], appDb);
  recordVersion("db", appDb.id, appDb.structure_id, appDb);
}

function updateStruct(struct) {
  update("structures", ["name", "route_prefix", "head_injection"], struct);
}

function updateTemplate(template) {
  update("templates", ["content", "name", "test_object"], template);
  templateCache.delete(template.structure_id);
  recordVersion("template", template.id, template.structure_id, template);
}

function getTemplates(structureId) {
  return db
    .prepare("SELECT * from templates where structure_id = ?")
    .all(structureId);
}

function getTemplate(templateId) {
  return db.prepare("SELECT * from templates where id = ?").get(templateId);
}

function getTemplateContentByName(structId, name) {
  return db
    .prepare(
      "SELECT content from templates where structure_id = ? AND name = ?",
    )
    .get(structId, name);
}

function getTemplateByName(structId, name) {
  return db
    .prepare("SELECT * from templates where structure_id = ? AND name = ?")
    .get(structId, name);
}

function createTemplate(structureId, name, content, testObjectString) {
  const id = db
    .prepare(
      "INSERT INTO templates (structure_id, name, content, test_object) VALUES (?, ?, ?, ?)",
    )
    .run(structureId, name, content, testObjectString).lastInsertRowid;
  recordVersion("template", id, structureId, {
    name,
    content,
    test_object: testObjectString,
  });
  return id;
}

function getDbsForStructure(structureId) {
  return db
    .prepare(
      `SELECT
          *,
          CASE
            WHEN structure_dbs.structure_id != dbs.structure_id THEN 1
            ELSE 0
          END AS is_aliased,
          structure_dbs.structure_id as alias_struct_id,
          dbs.structure_id as db_struct_id
       FROM structure_dbs
       INNER JOIN dbs ON structure_dbs.db_id = dbs.id
       WHERE structure_dbs.structure_id = ?
       ORDER BY structure_dbs.created_at, is_aliased ASC;
      `,
    )
    .all(structureId);
}

function getDb(dbId) {
  return db
    .prepare(
      `SELECT *
       FROM dbs
       WHERE id = ?;
      `,
    )
    .get(dbId);
}

function getDbForStructure(structureId, dbId) {
  return db
    .prepare(
      `SELECT *
      FROM structure_dbs
      INNER JOIN dbs ON structure_dbs.db_id = dbs.id
      WHERE structure_dbs.structure_id = ?
      AND structure_dbs.db_id = ?;
      `,
    )
    .get(structureId, dbId);
}

function createDb(structId, name) {
  const transaction = db.transaction(() => {
    const insertDbStmt = db.prepare(`
            INSERT INTO dbs (name, structure_id)
            VALUES (?, ?)
        `);
    const result = insertDbStmt.run(name, structId);
    const dbId = result.lastInsertRowid;
    const insertStructureDbStmt = db.prepare(`
            INSERT INTO structure_dbs (db_id, structure_id, alias)
            VALUES (?, ?, ?)
        `);
    insertStructureDbStmt.run(dbId, structId, name);

    const newDbPath = path.join("dbs", `${dbId}.sqlite`);
    const newDb = betterSqlite3(newDbPath);
    newDb.close();

    return dbId;
  });

  const dbId = transaction();
  recordVersion("db", dbId, structId, { name, library: "" });
  return dbId;
}

function attachDb(structId, dbId, alias) {
  const insertStructureDbStmt = db.prepare(`
    INSERT INTO structure_dbs (db_id, structure_id, alias)
    VALUES (?, ?, ?)
  `);
  insertStructureDbStmt.run(dbId, structId, alias);
}

function getFilesForStruct(structureId) {
  let test = db
    .prepare("SELECT * FROM files WHERE structure_id = ? ORDER BY id DESC")
    .all(structureId);

  return test;
}

function getFile(fileId) {
  return db.prepare("SELECT * FROM files WHERE id = ?").get(fileId);
}

function createFile(structure_id, name, filePath, mime_type, mime_subtype) {
  return db
    .prepare(
      "INSERT INTO files (structure_id, name, path, mime_type, mime_subtype) VALUES (?, ?, ?, ?, ?)",
    )
    .run(structure_id, name, filePath, mime_type, mime_subtype).lastInsertRowid;
}

function cloneStructure(
  structId,
  newStructureName,
  userId,
  routePrefix = "",
  cloneDbs = [],
) {
  const transaction = db.transaction(() => {
    const cloneStructure = db.prepare(`
            INSERT INTO structures (name, user_id, route_prefix, cloned_from)
            VALUES (?, ?, ?, ?);
        `);

    const newStructId = cloneStructure.run(
      newStructureName,
      userId,
      routePrefix,
      structId,
    ).lastInsertRowid;

    const dbIds = db
      .prepare(`SELECT db_id FROM structure_dbs WHERE structure_id = ?;`)
      .all(structId);

    const toClone = new Set(cloneDbs);
    const toAlias = new Set();

    for (let { db_id } of dbIds) {
      if (!toClone.has(db_id.toString())) {
        toAlias.add(db_id.toString());
      }
    }

    for (let db_id of toClone) {
      const newDb = db
        .prepare(
          `
            INSERT INTO dbs (name, structure_id, library)
            SELECT name, ?, library FROM dbs WHERE id = ?;
          `,
        )
        .run(newStructId, db_id).lastInsertRowid;

      db.prepare(
        `
            INSERT INTO structure_dbs (db_id, structure_id, alias)
            SELECT ?, ?, alias FROM structure_dbs WHERE db_id = ? AND structure_id = ?;
          `,
      ).run(newDb, newStructId, db_id, structId);

      db.prepare(`SELECT id FROM dbs WHERE structure_id = ?`)
        .all(newStructId)
        .map((new_db) => {
          const srcPath = path.join(__dirname, "dbs", `${db_id}.sqlite`);
          const destPath = path.join(__dirname, "dbs", `${new_db.id}.sqlite`);
          fs.copyFileSync(srcPath, destPath);
          fs.copyFileSync(srcPath + "-shm", destPath + "-shm");
          fs.copyFileSync(srcPath + "-wal", destPath + "-wal");
        });
    }

    for (let db_id of toAlias) {
      db.prepare(
        `
        INSERT INTO structure_dbs (db_id, structure_id, alias)
        SELECT db_id, ?, alias FROM structure_dbs WHERE structure_id = ? AND db_id = ?;
        `,
      ).run(newStructId, structId, db_id);
    }

    // Clone templates
    const cloneTemplates = db.prepare(`
            INSERT INTO templates (name, content, structure_id, test_object, engine)
            SELECT name, content, ?, test_object, engine FROM templates WHERE structure_id = ?;
        `);
    cloneTemplates.run(newStructId, structId);

    // Clone routes
    const cloneRoutes = db.prepare(`
            INSERT INTO routes (verb, path, structure_id, handler)
            SELECT verb, path, ?, handler FROM routes WHERE structure_id = ?;
        `);
    cloneRoutes.run(newStructId, structId);

    // Clone scaffold pages
    const cloneScaffoldPages = db.prepare(`
        INSERT INTO scaffold_pages (route_id, content, created_at)
        SELECT newRoutes.id, sp.content, sp.created_at
        FROM scaffold_pages sp
        JOIN routes oldRoutes ON sp.route_id = oldRoutes.id
        JOIN routes newRoutes ON oldRoutes.path = newRoutes.path AND oldRoutes.verb = newRoutes.verb
        WHERE oldRoutes.structure_id = ? AND newRoutes.structure_id = ?;
    `);
    cloneScaffoldPages.run(structId, newStructId);

    // Clone scaffold params
    const cloneScaffoldParams = db.prepare(`
        INSERT INTO scaffold_params (route_id, query_params, url_params, created_at)
        SELECT newRoutes.id, sp.query_params, sp.url_params, sp.created_at
        FROM scaffold_params sp
        JOIN routes oldRoutes ON sp.route_id = oldRoutes.id
        JOIN routes newRoutes ON oldRoutes.path = newRoutes.path AND oldRoutes.verb = newRoutes.verb
        WHERE oldRoutes.structure_id = ? AND newRoutes.structure_id = ?;
    `);
    cloneScaffoldParams.run(structId, newStructId);

    return newStructId;
  });

  return transaction();
}

function createLog(structureId, routeId, content, error = false) {
  const stmt = db.prepare(
    "INSERT INTO logs (error, structure_id, route_id, content) VALUES (?, ?, ?, ?)",
  );
  const info = stmt.run(error ? 1 : 0, structureId, routeId, content);
  return info.lastInsertRowid; // Returns the log_id of the newly created log
}

function getLogsByRoute(routeId) {
  return db
    .prepare(
      "SELECT * FROM logs WHERE route_id = ? ORDER BY created_at DESC LIMIT 50",
    )
    .all(routeId)
    .reverse();
}

function getNewLogsByRoute(routeId, since) {
  return db
    .prepare(
      "SELECT * FROM logs WHERE route_id = ? AND id > ? ORDER BY created_at DESC",
    )
    .all(routeId, since);
}

function getMostRecentLogIdByRoute(routeId) {
  const result = db
    .prepare("SELECT MAX(id) AS id FROM logs WHERE route_id = ?")
    .get(routeId);
  return result ? result.id : 0;
}

function buildScaffoldUrl(endpoint, urlParams, queryString) {
  let populatedUrl = endpoint.replace(/:([^/]+)/g, () => urlParams.shift() || '');
  return queryString ? `${populatedUrl}?${queryString}` : populatedUrl;
}

function createScaffoldPage(routeId, content=null) {
  if (!content) {
    const route = getRoute(routeId)
    const endpoint = buildScaffoldUrl(route.path, route.url_params, route.query_params);
    content = getDefaultScaffoldContentByVerb(endpoint, route.verb);
  }
  const stmt = db.prepare(
    "INSERT INTO scaffold_pages (route_id, content) VALUES (?, ?)"
  );
  const info = stmt.run(routeId, content);
  return info.lastInsertRowid; // Returns the scaffold_page id of the newly created scaffold page
}

function getLatestScaffoldPage(routeId) {
  const stmt = db.prepare(
    "SELECT * FROM scaffold_pages WHERE route_id = ? ORDER BY created_at DESC LIMIT 1"
  );
  return stmt.get(routeId);
}

function updateScaffoldPage(scaffoldPage) {
  return update("scaffold_pages", ["content"], scaffoldPage).changes > 0;
}

function generatePostForm(endpoint) {
  return `
    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Test POST Request</title>
        <script src="https://unpkg.com/htmx.org@1.9.2"></script>
    </head>
    <body>
        <h1>Test POST Request</h1>

        <form action="<%= it.route("${endpoint}") %>" method="POST">
            <!-- Add your form fields here to test post requests. -->
            <label for="testField">Test Field:</label>
            <input type="text" id="testField" name="testField" required>

            <button type="submit">Submit</button>
        </form>

        <!-- Add any divs for hx-swaps anywhere on the page. -->
        <div id="result" hx-swap="innerHTML"></div>
    </body>
    </html>
  `;
}

function generateModifyForm(endpoint, verb) {
  return `
    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Test ${verb} Request</title>
        <script src="https://unpkg.com/htmx.org@1.9.2"></script>
    </head>
    <body>
        <h1>Test ${verb} Request</h1>

        <form action="<%= it.route("${endpoint}") %>" method="${verb}">
            <!-- Add your form fields here to test ${verb.toLowerCase()} requests. -->
            <label for="testField">Test Field:</label>
            <input type="text" id="testField" name="testField" required>

            <button type="submit">${verb}</button>
        </form>

        <!-- Add any divs for hx-swaps anywhere on the page. -->
        <div id="result" hx-swap="innerHTML"></div>
    </body>
    </html>
  `;
}

function generateWSPage(endpoint) {
  return `
    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Test WebSocket</title>
    </head>
    <body>
        <h1>Test WebSocket Connection</h1>

        <input type="text" id="wsMessage" placeholder="Type a message">
        <button onclick="sendMessage()">Send</button>

        <div id="wsOutput"></div>

        <script>
            const ws = new WebSocket('<%= it.route("${endpoint}") %>');

            ws.onopen = () => {
                document.getElementById('wsOutput').innerHTML += '<p>Connected to WebSocket</p>';
            };

            ws.onmessage = (event) => {
                document.getElementById('wsOutput').innerHTML += '<p>Received: ' + event.data + '</p>';
            };

            ws.onclose = () => {
                document.getElementById('wsOutput').innerHTML += '<p>WebSocket connection closed</p>';
            };

            function sendMessage() {
                const message = document.getElementById('wsMessage').value;
                ws.send(message);
                document.getElementById('wsOutput').innerHTML += '<p>Sent: ' + message + '</p>';
            }
        </script>
    </body>
    </html>
  `;
}

function getDefaultScaffoldContentByVerb(url, verb) {
  if (verb == "POST") {
    return generatePostForm(url);
  }
  else if (verb == "PUT" || verb == "DELETE") {
    return generateModifyForm(url, verb);
  }
  else if (verb == "WS") {
    return generateWSPage(url);
  }
}

module.exports = {
  db,
  applyMigrations,
  getDbInstance,
  getAllRoutes,
  getUser,
  getUserById,
  createUser,
  getStructures,
  getStructure,
  createStructure,
  createRoute,
  getRoutes,
  getRoute,
  buildScaffoldUrl,
  updateRoute,
  updateDb,
  updateStruct,
  updateTemplate,
  getVersions,
  getVersion,
  getTemplater,
  getTemplates,
  getTemplate,
  getTemplateContentByName,
  getTemplateByName,
  createTemplate,
  getDbsForStructure,
  getDb,
  getDbForStructure,
  createDb,
  attachDb,
  getFilesForStruct,
  getFile,
  createFile,
  cloneStructure,
  createLog,
  getLogsByRoute,
  getNewLogsByRoute,
  getMostRecentLogIdByRoute,
  createScaffoldPage,
  getLatestScaffoldPage,
  updateScaffoldPage
};