using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace TMSDAL.DTO.AttemptResponse
{
    /// <summary>
    /// Maps to DBO.TATTEMPTRESPONSE
    /// Per-question response within one assessment attempt.
    /// Detail of TASSESSMENTATTEMPT — one row per question answered.
    /// ASSESSMENTQUESTIONID and QUESTIONBANKID are mutually exclusive:
    ///   Simple mode  → ASSESSMENTQUESTIONID > 0, QUESTIONBANKID = -1
    ///   Structured   → QUESTIONBANKID > 0,       ASSESSMENTQUESTIONID = -1
    /// ISCORRECT: -1 = Pending, 0 = Wrong, 1 = Correct
    /// </summary>
    public class AttemptResponseDTO
    {
        // =====================================================
        // PRIMARY KEY
        // =====================================================
        public int AttemptResponseId { get; set; }

        // =====================================================
        // PARENT FK
        // =====================================================

        /// <summary>FK → TASSESSMENTATTEMPT.ASSESSMENTATTEMPTID</summary>
        public int AssessmentAttemptId { get; set; }

        // =====================================================
        // FOREIGN KEYS + JOINED DISPLAY FIELDS
        // =====================================================

        /// <summary>
        /// FK → MASSESSMENTQUESTION.ASSESSMENTQUESTIONID
        /// -1 when QuestionBankId is used (Structured mode).
        /// </summary>
        public int AssessmentQuestionId { get; set; } = -1;

        /// <summary>
        /// FK → MQUESTIONBANK.QUESTIONBANKID
        /// -1 when AssessmentQuestionId is used (Simple mode).
        /// </summary>
        public int QuestionBankId { get; set; } = -1;

        /// <summary>
        /// Joined — COALESCE(MASSESSMENTQUESTION.QUESTIONTEXT, MQUESTIONBANK.QUESTIONTEXT)
        /// Display reference only — shows question text regardless of mode.
        /// </summary>
        public string? QuestionText { get; set; }

        /// <summary>
        /// Joined — MQUESTIONBANK.QUESTIONTITLE
        /// Short title of the question for list display. Null in Simple mode
        /// (MASSESSMENTQUESTION has no title column, only QuestionText).
        /// </summary>
        public string? QuestionTitle { get; set; }

        // =====================================================
        // BUSINESS COLUMNS
        // =====================================================

        /// <summary>
        /// Answer submitted by the employee.
        /// MCQ/TrueFalse = option key e.g. "A" / "True".
        /// ShortAnswer/Essay = free text.
        /// Matching = JSON pairs e.g. [{"left":"A","right":"1"}].
        /// Null = question skipped.
        /// </summary>
        public string? ResponseGiven { get; set; }

        /// <summary>
        /// -1 = Pending manual evaluation.
        ///  0 = Wrong.
        ///  1 = Correct.
        /// SMALLINT to accommodate -1 sentinel.
        /// </summary>
        public short IsCorrect { get; set; } = -1;

        /// <summary>
        /// Numeric(9,4) — marks awarded for this response.
        /// 0 for wrong/pending. Full marks for correct.
        /// Partial marks allowed for manual types.
        /// </summary>
        public decimal MarksAwarded { get; set; } = 0;

        /// <summary>
        /// Optional evaluator notes for this specific response.
        /// Used for Observation/Practical/Assignment types.
        /// Max 1000 characters.
        /// </summary>
        public string? EvaluatorNotes { get; set; }
    }
}