package pipeline

import (
	"context"
	"fmt"
	"log"
	"spider/internal/model"

	"github.com/redis/go-redis/v9"
	"gorm.io/gorm"
)

// fullPhaseOrder defines the sequential execution order for a full pipeline run.
var fullPhaseOrder = []string{
	"discover",
	"search",
	"github",
	"scrape",
	"crawl",
	"clean",
	"score",
}

// Runner Pipeline 调度器
type Runner struct {
	db       *gorm.DB
	redis    *redis.Client
	phases   map[string]Phase // 注册的 phase，key 是 phase 名称
	reporter ProgressReporter
}

// NewRunner creates a new pipeline Runner.
func NewRunner(db *gorm.DB, rdb *redis.Client) *Runner {
	return &Runner{
		db:    db,
		redis: rdb,
		phases: make(map[string]Phase),
	}
}

// RegisterPhase 注册一个 phase 实现
func (r *Runner) RegisterPhase(p Phase) {
	r.phases[p.Name()] = p
}

// SetProgressReporter 设置进度上报函数
func (r *Runner) SetProgressReporter(fn ProgressReporter) {
	r.reporter = fn
}

// report calls the reporter if one is set; otherwise logs to stderr.
func (r *Runner) report(phase string, current, total int, message string) {
	if r.reporter != nil {
		r.reporter(phase, current, total, message)
	}
}

// Run 执行 pipeline
// task.TaskType: "full" | "discover" | "search" | "github" | "scrape" | "crawl" | "clean" | "score"
// full 类型按顺序执行所有未跳过的 phase
// 单阶段类型直接执行对应 phase
func (r *Runner) Run(ctx context.Context, task *model.Task, opts *Options) error {
	if task.TaskType == "full" {
		for _, phaseName := range fullPhaseOrder {
			if isContextDone(ctx) {
				return fmt.Errorf("pipeline cancelled before phase %s", phaseName)
			}
			if ShouldSkip(phaseName, opts.SkipPhases) {
				log.Printf("[pipeline] skipping phase=%s (in SkipPhases)", phaseName)
				continue
			}
			r.report(phaseName, 0, 0, "开始 "+phaseName)
			if err := r.runSingle(ctx, task, phaseName, opts); err != nil {
				log.Printf("[pipeline] phase=%s error: %v (continuing)", phaseName, err)
			}
			r.report(phaseName, 100, 100, phaseName+" 完成")
		}
		return nil
	}

	// Single-phase task
	phaseName := task.TaskType
	if isContextDone(ctx) {
		return fmt.Errorf("pipeline cancelled before phase %s", phaseName)
	}
	r.report(phaseName, 0, 0, "开始 "+phaseName)
	if err := r.runSingle(ctx, task, phaseName, opts); err != nil {
		r.report(phaseName, 0, 0, phaseName+" 失败: "+err.Error())
		return err
	}
	r.report(phaseName, 100, 100, phaseName+" 完成")
	return nil
}

// runSingle 执行单个 phase
func (r *Runner) runSingle(ctx context.Context, task *model.Task, phaseName string, opts *Options) error {
	p, ok := r.phases[phaseName]
	if !ok {
		return fmt.Errorf("phase %q not registered", phaseName)
	}
	return p.Run(ctx, task, opts)
}

// isContextDone 检查 context 是否已取消（用于各阶段检查停止信号）
func isContextDone(ctx context.Context) bool {
	select {
	case <-ctx.Done():
		return true
	default:
		return false
	}
}