using System;

namespace TMSDAL.DTO.AssessmentQuestion
{
    /// <summary>
    /// DTO for MASSESSMENTQUESTION table.
    /// Simple mode — questions attached directly to an assessment definition.
    /// Detail of MSESSIONASSESSMENT.
    ///
    /// QUESTIONTYPE:
    ///   0 = MCQ          — single correct option from multiple choices
    ///   1 = TrueFalse    — binary true/false answer
    ///   2 = ShortAnswer  — free-text response
    ///   3 = MultiSelect  — one or more correct options
    ///   4 = Matching     — match pairs (left → right)
    ///   5 = Ordering     — arrange items in correct sequence
    ///
    /// OPTIONSJSON  — nullable; stores MCQ/MultiSelect/Matching/Ordering options as JSON
    /// EXPLANATION  — nullable; shown after attempt if ShowAnswersOnComplete = 1
    ///
    /// No standard audit fields (CREATEDBYID / CREATEDON etc.) on this table.
    /// </summary>
    public class AssessmentQuestionDTO
    {
        #region Private Members

        // ── Primary Key ───────────────────────────────────────────────────────
        private int assessmentquestionid;

        // ── Parent FK ─────────────────────────────────────────────────────────
        private int assessmentid;

        // ── Sequence ──────────────────────────────────────────────────────────
        private short slno;                    // DEFAULT 1

        // ── Business Columns ──────────────────────────────────────────────────
        private string questiontext;          // NVARCHAR(MAX) NOT NULL
        private byte questiontype;          // 0-5           NOT NULL  DEFAULT 0
        private string? optionsjson;           // NVARCHAR(MAX) NULL  — JSON array of options
        private string correctanswer;         // NVARCHAR(MAX) NOT NULL
        private short marks;                 // SMALLINT      NOT NULL  DEFAULT 1
        private string? explanation;           // NVARCHAR(MAX) NULL
        private byte requiresmanualevaluation; // 0 No, 1 Yes  NOT NULL  DEFAULT 0

        // ── Read-only Joined Fields (GET only — not saved) ────────────────────
        private string? assessmenttitle;       // From MSESSIONASSESSMENT

        #endregion

        #region Public Members

        // ── Primary Key ───────────────────────────────────────────────────────

        /// <summary>PK — ASSESSMENTQUESTIONID</summary>
        public int AssessmentQuestionId
        {
            get { return assessmentquestionid; }
            set { assessmentquestionid = value; }
        }

        // ── Parent FK ─────────────────────────────────────────────────────────

        /// <summary>FK → MSESSIONASSESSMENT.ASSESSMENTID (NOT NULL)</summary>
        public int AssessmentId
        {
            get { return assessmentid; }
            set { assessmentid = value; }
        }

        // ── Sequence ──────────────────────────────────────────────────────────

        /// <summary>
        /// Question display order within the assessment (NOT NULL, DEFAULT 1)
        /// SMALLINT → short (range: -32,768 to 32,767)
        /// </summary>
        public short SlNo
        {
            get { return slno; }
            set { slno = value; }
        }

        // ── Business Columns ──────────────────────────────────────────────────

        /// <summary>
        /// Full question text (NOT NULL, NVARCHAR MAX)
        /// Supports rich text / HTML for formatted questions.
        /// </summary>
        public string QuestionText
        {
            get { return questiontext; }
            set { questiontext = value; }
        }

        /// <summary>
        /// Question type (NOT NULL, DEFAULT 0)
        /// 0 = MCQ         — single correct option
        /// 1 = TrueFalse   — binary answer
        /// 2 = ShortAnswer — free-text
        /// 3 = MultiSelect — one or more correct options
        /// 4 = Matching    — match left → right pairs
        /// 5 = Ordering    — arrange in correct sequence
        /// CHECK: IN (0,1,2,3,4,5)
        /// TINYINT → byte
        /// </summary>
        public byte QuestionType
        {
            get { return questiontype; }
            set { questiontype = value; }
        }

        /// <summary>
        /// Options stored as JSON (NULLABLE, NVARCHAR MAX)
        /// Used by: MCQ, MultiSelect, Matching, Ordering
        /// Null for: TrueFalse, ShortAnswer
        ///
        /// MCQ / MultiSelect example:
        ///   [{"id":1,"text":"Option A"},{"id":2,"text":"Option B"}]
        ///
        /// Matching example:
        ///   [{"left":"Term A","right":"Definition A"},{"left":"Term B","right":"Definition B"}]
        ///
        /// Ordering example:
        ///   [{"id":1,"text":"Step 1"},{"id":2,"text":"Step 2"}]
        /// </summary>
        public string? OptionsJson
        {
            get { return optionsjson; }
            set { optionsjson = value; }
        }

        /// <summary>
        /// Correct answer (NOT NULL, NVARCHAR MAX)
        /// Stored as a string regardless of question type:
        ///
        /// MCQ         → option id as string         e.g. "2"
        /// TrueFalse   → "true" or "false"
        /// ShortAnswer → expected answer text        e.g. "photosynthesis"
        /// MultiSelect → comma-separated option ids  e.g. "1,3"
        /// Matching    → JSON pairs                  e.g. [{"left":1,"right":2}]
        /// Ordering    → JSON ordered id array       e.g. "[3,1,2,4]"
        /// </summary>
        public string CorrectAnswer
        {
            get { return correctanswer; }
            set { correctanswer = value; }
        }

        /// <summary>
        /// Marks awarded for a correct answer (NOT NULL, DEFAULT 1)
        /// SMALLINT → short
        /// </summary>
        public short Marks
        {
            get { return marks; }
            set { marks = value; }
        }

        /// <summary>
        /// Explanation shown after attempt (NULLABLE, NVARCHAR MAX)
        /// Displayed only when MSESSIONASSESSMENT.SHOWANSWERSONCOMPLETE = 1
        /// </summary>
        public string? Explanation
        {
            get { return explanation; }
            set { explanation = value; }
        }

        /// <summary>
        /// 0 = No (default auto-eval by exact-match against CorrectAnswer), 1 = Yes — always
        /// route this question's response through IAssessmentAnswerEvaluationService (human
        /// grader today, pluggable AI evaluator later) regardless of whether CorrectAnswer is set.
        /// </summary>
        public byte RequiresManualEvaluation
        {
            get { return requiresmanualevaluation; }
            set { requiresmanualevaluation = value; }
        }

        // ── Read-only Joined Fields (GET only — never included in INSERT/UPDATE) ─

        /// <summary>From MSESSIONASSESSMENT.ASSESSMENTTITLE (GET only)</summary>
        public string? AssessmentTitle
        {
            get { return assessmenttitle; }
            set { assessmenttitle = value; }
        }

        #endregion
    }
}