package com.learn.controller.jpa;

import com.learn.entity.Student;
import com.learn.service.jpa.StudentJpaService;
import jakarta.validation.Valid;
import org.springframework.data.domain.Page;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import java.util.HashMap;
import java.util.Map;

/**
 * JPA 版本的学生管理 REST API
 *
 * 访问路径全部以 /api/jpa/students 开头，
 * 与 MyBatis-Plus 版本（/api/mp/students）区分，方便对比测试。
 */
@RestController
@RequestMapping("/api/jpa/students")
public class StudentJpaController {

    private final StudentJpaService service;

    public StudentJpaController(StudentJpaService service) {
        this.service = service;
    }

    /** 查询全部 / 搜索 */
    @GetMapping
    public ResponseEntity<Map<String, Object>> list(
            @RequestParam(required = false) String keyword) {

        java.util.List<Student> students;
        if (keyword != null && !keyword.trim().isEmpty()) {
            students = service.searchByKeyword(keyword);
        } else {
            students = service.list();
        }

        return ok(students);
    }

    /** 分页查询（第 5 天） */
    @GetMapping("/page")
    public ResponseEntity<Map<String, Object>> page(
            @RequestParam(defaultValue = "1") int pageNum,
            @RequestParam(defaultValue = "5") int pageSize) {

        Page<Student> page = service.page(pageNum, pageSize);

        Map<String, Object> result = new HashMap<>();
        result.put("code", 200);
        result.put("total", page.getTotalElements());
        result.put("pages", page.getTotalPages());
        result.put("current", page.getNumber() + 1);
        result.put("data", page.getContent());
        return ResponseEntity.ok(result);
    }

    /** 根据 ID 查询 */
    @GetMapping("/{id}")
    public ResponseEntity<Map<String, Object>> getById(@PathVariable Long id) {
        return service.getById(id)
                .map(s -> ok(s))
                .orElse(notFound(id));
    }

    /** 新增 */
    @PostMapping
    public ResponseEntity<Map<String, Object>> add(@Valid @RequestBody Student student) {
        Student saved = service.add(student);
        Map<String, Object> result = new HashMap<>();
        result.put("code", 201);
        result.put("message", "添加成功");
        result.put("data", saved);
        return ResponseEntity.status(HttpStatus.CREATED).body(result);
    }

    /** 更新 */
    @PutMapping("/{id}")
    public ResponseEntity<Map<String, Object>> update(
            @PathVariable Long id, @Valid @RequestBody Student student) {
        return service.update(id, student)
                .map(updated -> {
                    Map<String, Object> result = new HashMap<>();
                    result.put("code", 200);
                    result.put("message", "更新成功");
                    result.put("data", updated);
                    return ResponseEntity.ok(result);
                })
                .orElse(notFound(id));
    }

    /** 删除 */
    @DeleteMapping("/{id}")
    public ResponseEntity<Map<String, Object>> delete(@PathVariable Long id) {
        if (service.delete(id)) {
            return ResponseEntity.ok(Map.of("code", 200, "message", "删除成功"));
        }
        return notFound(id);
    }

    /** 分数统计 */
    @GetMapping("/stats")
    public ResponseEntity<Map<String, Object>> stats(
            @RequestParam(defaultValue = "80") int min,
            @RequestParam(defaultValue = "100") int max) {
        long count = service.countByScoreRange(min, max);
        Map<String, Object> result = new HashMap<>();
        result.put("code", 200);
        result.put("range", min + "-" + max);
        result.put("count", count);
        return ResponseEntity.ok(result);
    }

    // ==================== 工具方法 ====================

    private ResponseEntity<Map<String, Object>> ok(Object data) {
        Map<String, Object> result = new HashMap<>();
        result.put("code", 200);
        result.put("data", data);
        return ResponseEntity.ok(result);
    }

    private ResponseEntity<Map<String, Object>> notFound(Long id) {
        Map<String, Object> error = new HashMap<>();
        error.put("code", 404);
        error.put("message", "学生不存在，ID: " + id);
        return ResponseEntity.status(HttpStatus.NOT_FOUND).body(error);
    }
}