package health

import (
	"context"
	"fmt"
	"net/http"
	"runtime/debug"
	"strings"
	"time"

	"git.apinb.com/ops/files/internal/config"
	"git.apinb.com/ops/files/internal/impl"
	"git.apinb.com/ops/files/internal/jobs"
	"git.apinb.com/ops/files/internal/runtimeinfo"
	"git.apinb.com/ops/files/internal/storage"
	"github.com/gin-gonic/gin"
	"gorm.io/gorm"
)

type CheckResult struct {
	Name     string `json:"name"`
	Required bool   `json:"required"`
	Ready    bool   `json:"ready"`
	Message  string `json:"message,omitempty"`
}
type Readiness struct {
	Ready     bool          `json:"ready"`
	CheckedAt time.Time     `json:"checked_at"`
	Checks    []CheckResult `json:"checks,omitempty"`
	Version   string        `json:"version"`
}

type FileCounts struct {
	Total   int64 `json:"total"`
	Ready   int64 `json:"ready"`
	Pending int64 `json:"pending"`
}

func Evaluate(ctx context.Context) Readiness {
	result, _ := evaluate(ctx)
	return result
}

func evaluate(ctx context.Context) (Readiness, storage.RuntimeStatus) {
	result := Readiness{Ready: true, CheckedAt: time.Now().UTC(), Version: runtimeVersion()}
	result.add("config", true, config.Validate())
	result.add("database", true, pingDatabase(ctx, impl.DBService))
	storageStatus, storageErr := impl.StorageService.Status(ctx)
	if storageErr == nil && !storageStatus.Writable {
		storageErr = fmt.Errorf("文件存储当前不可写")
	}
	result.add("storage", true, storageErr)
	worker := jobs.Status()
	if worker.Running {
		result.add("pending_upload_cleanup", true, nil)
	} else {
		result.add("pending_upload_cleanup", true, fmt.Errorf("过期上传清理任务未运行"))
	}
	integrity := jobs.IntegrityStatusSnapshot()
	if integrity.Running {
		result.add("integrity_worker", true, nil)
	} else {
		result.add("integrity_worker", true, fmt.Errorf("文件完整性任务未运行"))
	}
	if integrity.Missing+integrity.SizeMismatch+integrity.ETagMismatch > 0 {
		result.add("file_integrity", false, fmt.Errorf("发现文件缺失或校验不一致"))
	} else {
		result.add("file_integrity", false, nil)
	}
	return result, storageStatus
}

func runtimeVersion() string {
	info, ok := debug.ReadBuildInfo()
	if !ok || strings.TrimSpace(info.Main.Version) == "" {
		return "unknown"
	}
	return info.Main.Version
}
func Ready(c *gin.Context) {
	result := Evaluate(c.Request.Context())
	status := http.StatusOK
	if !result.Ready {
		status = http.StatusServiceUnavailable
	}
	c.JSON(status, gin.H{"ready": result.Ready})
}
func Status(c *gin.Context) {
	result, storageStatus := evaluate(c.Request.Context())
	status := http.StatusOK
	if !result.Ready {
		status = http.StatusServiceUnavailable
	}
	counts, countErr := fileCounts(c.Request.Context())
	if countErr != nil {
		result.add("file_ledger", true, countErr)
		status = http.StatusServiceUnavailable
	}
	c.JSON(status, gin.H{
		"readiness": result,
		"workers": gin.H{
			"pending_upload_cleanup": jobs.Status(),
			"integrity":              jobs.IntegrityStatusSnapshot(),
		},
		"storage":  storageStatus,
		"disk":     storageStatus.Disk,
		"files":    counts,
		"activity": runtimeinfo.Snapshot(),
	})
}

func fileCounts(ctx context.Context) (FileCounts, error) {
	var counts FileCounts
	err := impl.DBService.WithContext(ctx).Raw(`
SELECT COUNT(*) AS total,
       COUNT(*) FILTER (WHERE status = 'ready') AS ready,
       COUNT(*) FILTER (WHERE status = 'pending') AS pending
FROM files_object
WHERE deleted_at IS NULL`).Scan(&counts).Error
	return counts, err
}
func (r *Readiness) add(name string, required bool, err error) {
	check := CheckResult{Name: name, Required: required, Ready: err == nil}
	if err != nil {
		check.Message = strings.TrimSpace(err.Error())
		if required {
			r.Ready = false
		}
	}
	r.Checks = append(r.Checks, check)
}
func pingDatabase(ctx context.Context, db *gorm.DB) error {
	if db == nil {
		return fmt.Errorf("数据库未初始化")
	}
	sqlDB, err := db.DB()
	if err != nil {
		return err
	}
	checkCtx, cancel := context.WithTimeout(ctx, 2*time.Second)
	defer cancel()
	return sqlDB.PingContext(checkCtx)
}