package handlers

import (
	"net/http"
	"strings"

	"github.com/gin-gonic/gin"

	"query-database/api/internal/auth"
)

type exerciseSummary struct {
	ID       string `json:"id"`
	Title    string `json:"title"`
	Level    string `json:"level"`
	Database string `json:"databaseKey"`
	IsSolved bool   `json:"isSolved"`
}

func (h *Handlers) ListExercises(c *gin.Context) {
	userID := auth.UserID(c)
	level := strings.TrimSpace(c.Query("level"))
	if level == "" {
		level = "beginner"
	}
	if level != "beginner" && level != "normal" && level != "advanced" {
		c.JSON(http.StatusBadRequest, gin.H{"message": "level 不合法"})
		return
	}

	moduleKey := strings.TrimSpace(c.Query("moduleKey"))
	if moduleKey == "" {
		_ = h.sqlite.QueryRow(`SELECT module_key FROM users WHERE id = ?`, userID).Scan(&moduleKey)
	}
	if moduleKey != "shop" && moduleKey != "hr" {
		c.JSON(http.StatusBadRequest, gin.H{"message": "moduleKey 不合法"})
		return
	}

	rows, err := h.sqlite.Query(
		`SELECT e.id, e.title, e.level, e.database_key,
        COALESCE(p.is_solved, 0) AS is_solved
     FROM exercises e
     LEFT JOIN progress p ON p.exercise_id = e.id AND p.user_id = ?
     WHERE e.level = ? AND e.database_key = ?
     ORDER BY e.created_at ASC`,
		userID,
		level,
		moduleKey,
	)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"message": "服务异常"})
		return
	}
	defer rows.Close()

	out := make([]exerciseSummary, 0)
	for rows.Next() {
		var id, title, lvl, dbKey string
		var solved int
		if err := rows.Scan(&id, &title, &lvl, &dbKey, &solved); err != nil {
			c.JSON(http.StatusInternalServerError, gin.H{"message": "服务异常"})
			return
		}
		out = append(out, exerciseSummary{ID: id, Title: title, Level: lvl, Database: dbKey, IsSolved: solved == 1})
	}
	c.JSON(http.StatusOK, out)
}

type exerciseDetail struct {
	ID       string `json:"id"`
	Title    string `json:"title"`
	Level    string `json:"level"`
	Prompt   string `json:"prompt"`
	Database string `json:"databaseKey"`
	IsSolved bool   `json:"isSolved"`
	DraftSQL string `json:"draftSql"`
}

func (h *Handlers) GetExercise(c *gin.Context) {
	userID := auth.UserID(c)
	id := c.Param("id")
	var title, level, prompt, dbKey string
	if err := h.sqlite.QueryRow(`SELECT title, level, prompt, database_key FROM exercises WHERE id = ?`, id).Scan(&title, &level, &prompt, &dbKey); err != nil {
		c.JSON(http.StatusNotFound, gin.H{"message": "题目不存在"})
		return
	}
	var draft string
	var solved int
	_ = h.sqlite.QueryRow(
		`SELECT draft_sql, is_solved FROM progress WHERE user_id = ? AND exercise_id = ?`,
		userID,
		id,
	).Scan(&draft, &solved)

	c.JSON(http.StatusOK, exerciseDetail{
		ID: id, Title: title, Level: level, Prompt: prompt, Database: dbKey, IsSolved: solved == 1, DraftSQL: draft,
	})
}