import type { Database, SqlValue } from 'sql.js';
import type { Recipe, CreateRecipeInput, UpdateRecipeInput, RecipeFilters } from '../types/recipe.js';

/**
 * RecipeRepository handles all database operations for recipes.
 */
export class RecipeRepository {
  constructor(private db: Database) {}

  /**
   * Find all recipes with optional filtering and pagination
   */
  findAll(filters: RecipeFilters = {}): Recipe[] {
    const { search, offset = 0, limit = 50 } = filters;
    
    let sql = 'SELECT * FROM recipes';
    const params: SqlValue[] = [];

    if (search) {
      sql += ' WHERE title LIKE ? OR description LIKE ? OR ingredients LIKE ?';
      const searchPattern = `%${search}%`;
      params.push(searchPattern, searchPattern, searchPattern);
    }

    sql += ' ORDER BY created_at DESC LIMIT ? OFFSET ?';
    params.push(limit, offset);

    const result = this.db.exec(sql, params);
    if (!result.length) return [];

    return this.rowsToRecipes(result[0]);
  }

  /**
   * Find a recipe by ID
   */
  findById(id: number): Recipe | null {
    const result = this.db.exec('SELECT * FROM recipes WHERE id = ?', [id]);
    if (!result.length || !result[0].values.length) return null;

    const recipes = this.rowsToRecipes(result[0]);
    return recipes[0] || null;
  }

  /**
   * Create a new recipe
   */
  create(input: CreateRecipeInput): Recipe {
    const now = Math.floor(Date.now() / 1000);
    
    const sql = `
      INSERT INTO recipes (
        title, description, ingredients, instructions, 
        source_url, notes, servings, prep_time_minutes, 
        cook_time_minutes, created_at, updated_at
      ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
    `;

    this.db.run(sql, [
      input.title,
      input.description || null,
      JSON.stringify(input.ingredients),
      JSON.stringify(input.instructions),
      input.source_url || null,
      input.notes || null,
      input.servings || null,
      input.prep_time_minutes || null,
      input.cook_time_minutes || null,
      now,
      now,
    ]);

    // Get the last inserted ID
    const result = this.db.exec('SELECT last_insert_rowid() as id');
    const id = result[0].values[0][0] as number;

    return this.findById(id)!;
  }

  /**
   * Update an existing recipe
   */
  update(id: number, input: UpdateRecipeInput): Recipe | null {
    const existing = this.findById(id);
    if (!existing) return null;

    const now = Math.floor(Date.now() / 1000);
    const fields: string[] = [];
    const params: SqlValue[] = [];

    // Build dynamic UPDATE query based on provided fields
    if (input.title !== undefined) {
      fields.push('title = ?');
      params.push(input.title);
    }
    if (input.description !== undefined) {
      fields.push('description = ?');
      params.push(input.description);
    }
    if (input.ingredients !== undefined) {
      fields.push('ingredients = ?');
      params.push(JSON.stringify(input.ingredients));
    }
    if (input.instructions !== undefined) {
      fields.push('instructions = ?');
      params.push(JSON.stringify(input.instructions));
    }
    if (input.source_url !== undefined) {
      fields.push('source_url = ?');
      params.push(input.source_url);
    }
    if (input.notes !== undefined) {
      fields.push('notes = ?');
      params.push(input.notes);
    }
    if (input.servings !== undefined) {
      fields.push('servings = ?');
      params.push(input.servings);
    }
    if (input.prep_time_minutes !== undefined) {
      fields.push('prep_time_minutes = ?');
      params.push(input.prep_time_minutes);
    }
    if (input.cook_time_minutes !== undefined) {
      fields.push('cook_time_minutes = ?');
      params.push(input.cook_time_minutes);
    }

    // Always update updated_at
    fields.push('updated_at = ?');
    params.push(now);

    // Add ID to params for WHERE clause
    params.push(id);

    const sql = `UPDATE recipes SET ${fields.join(', ')} WHERE id = ?`;
    this.db.run(sql, params);

    return this.findById(id);
  }

  /**
   * Delete a recipe
   */
  delete(id: number): boolean {
    const existing = this.findById(id);
    if (!existing) return false;

    this.db.run('DELETE FROM recipes WHERE id = ?', [id]);
    return true;
  }

  /**
   * Count total recipes (for pagination)
   */
  count(filters: RecipeFilters = {}): number {
    const { search } = filters;
    
    let sql = 'SELECT COUNT(*) as count FROM recipes';
    const params: SqlValue[] = [];

    if (search) {
      sql += ' WHERE title LIKE ? OR description LIKE ? OR ingredients LIKE ?';
      const searchPattern = `%${search}%`;
      params.push(searchPattern, searchPattern, searchPattern);
    }

    const result = this.db.exec(sql, params);
    return result[0].values[0][0] as number;
  }

  /**
   * Convert sql.js result rows to Recipe objects
   */
  private rowsToRecipes(result: { columns: string[]; values: SqlValue[][] }): Recipe[] {
    return result.values.map((row) => {
      const recipe: Record<string, SqlValue> = {};
      result.columns.forEach((col, idx) => {
        recipe[col] = row[idx];
      });

      return {
        id: recipe.id as number,
        title: recipe.title as string,
        description: recipe.description as string | null,
        ingredients: JSON.parse(recipe.ingredients as string) as string[],
        instructions: JSON.parse(recipe.instructions as string) as string[],
        source_url: recipe.source_url as string | null,
        notes: recipe.notes as string | null,
        servings: recipe.servings as number | null,
        prep_time_minutes: recipe.prep_time_minutes as number | null,
        cook_time_minutes: recipe.cook_time_minutes as number | null,
        created_at: recipe.created_at as number,
        updated_at: recipe.updated_at as number,
        last_cooked_at: recipe.last_cooked_at as number | null,
      };
    });
  }
}