package data

import (
	"context"
	"errors"
	"fmt"
	"io"
	"log/slog"
	"time"

	"gorm.io/gorm/logger"
)

// gormLogger forwards GORM diagnostics through the application logger so SQL
// entries participate in the same daily/category files and error sink as the
// rest of the service. Slow queries use the administration contract's 200ms
// threshold.
type gormLogger struct {
	logger        *slog.Logger
	slowThreshold time.Duration
	level         logger.LogLevel
}

func newGormLogger(log *slog.Logger, level logger.LogLevel) *gormLogger {
	if log == nil {
		log = slog.New(slog.NewTextHandler(io.Discard, nil))
	}
	return &gormLogger{logger: log, slowThreshold: 200 * time.Millisecond, level: level}
}

func (g *gormLogger) LogMode(level logger.LogLevel) logger.Interface {
	next := *g
	next.level = level
	return &next
}

func (g *gormLogger) Info(ctx context.Context, message string, args ...any) {
	g.logger.InfoContext(ctx, fmt.Sprintf(message, args...), "mod", "sql", "gorm_logger", true)
}

func (g *gormLogger) Warn(ctx context.Context, message string, args ...any) {
	g.logger.WarnContext(ctx, fmt.Sprintf(message, args...), "mod", "sql", "gorm_logger", true)
}

func (g *gormLogger) Error(ctx context.Context, message string, args ...any) {
	g.logger.ErrorContext(ctx, fmt.Sprintf(message, args...), "mod", "sql", "gorm_logger", true)
}

func (g *gormLogger) Trace(ctx context.Context, begin time.Time, query func() (string, int64), queryErr error) {
	if g.level <= logger.Silent {
		return
	}
	elapsed := time.Since(begin)
	sql, rows := query()
	fields := []any{"mod", "sql", "gorm_logger", true, "sql", sql, "rows", rows, "elapsed_ms", elapsed.Milliseconds()}
	switch {
	case queryErr != nil && g.level >= logger.Error && !errors.Is(queryErr, logger.ErrRecordNotFound):
		fields = append(fields, "error", queryErr)
		g.logger.ErrorContext(ctx, "SQL 执行错误", fields...)
	case elapsed > g.slowThreshold && g.level >= logger.Warn:
		g.logger.WarnContext(ctx, "SQL 慢查询", fields...)
	case g.level >= logger.Info:
		g.logger.InfoContext(ctx, "SQL", fields...)
	}
}