package com.kaidi.oa.web;

import com.kaidi.oa.common.ApiResp;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.sql.DataSource;
import java.nio.file.Files;
import java.nio.file.InvalidPathException;
import java.nio.file.Path;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.Map;

/** Readiness probe used by the installer and online-update rollback gate. */
@RestController
@RequestMapping("/api/oa")
public class HealthController {

    private final DataSource dataSource;
    private final Path installLockFile;

    public HealthController(DataSource dataSource,
                            @Value("${ERP_INSTALL_LOCK_FILE:}") String installLockFile) {
        this.dataSource = dataSource;
        this.installLockFile = resolveInstallLockFile(installLockFile);
    }

    @GetMapping("/health")
    public ResponseEntity<ApiResp<Map<String, String>>> health() {
        try (Connection connection = dataSource.getConnection();
                Statement statement = connection.createStatement();
                ResultSet result = statement.executeQuery("SELECT 1")) {
            if (connection.isValid(2) && result.next() && result.getInt(1) == 1) {
                return ResponseEntity.ok(ApiResp.ok(readiness("UP", "UP")));
            }
        } catch (Exception ignored) {
            // Health responses deliberately avoid exposing connection details.
        }
        return ResponseEntity.status(HttpStatus.SERVICE_UNAVAILABLE)
                .body(new ApiResp<>(50301, "database unavailable", readiness("DOWN", "DOWN")));
    }

    private Map<String, String> readiness(String status, String database) {
        return Map.of(
                "status", status,
                "database", database,
                "installLocked", Boolean.toString(installLockFile != null && Files.isRegularFile(installLockFile))
        );
    }

    private static Path resolveInstallLockFile(String value) {
        if (value == null || value.isBlank()) {
            return null;
        }
        try {
            return Path.of(value).toAbsolutePath().normalize();
        } catch (InvalidPathException ignored) {
            return null;
        }
    }
}