package usecase

import (
	"context"
	"crypto/sha256"
	"encoding/hex"
	"strings"

	"haixun-backend/internal/library/clock"
	app "haixun-backend/internal/library/errors"
	"haixun-backend/internal/library/errors/code"
	"haixun-backend/internal/model/job/domain/entity"
	"haixun-backend/internal/model/job/domain/enum"
	domusecase "haixun-backend/internal/model/job/domain/usecase"
)

func stringFromAny(value any) string {
	switch v := value.(type) {
	case string:
		return strings.TrimSpace(v)
	default:
		return ""
	}
}

func extractRunActor(req domusecase.CreateRunRequest) (tenantID, ownerUID string) {
	tenantID = strings.TrimSpace(req.TenantID)
	ownerUID = strings.TrimSpace(req.OwnerUID)
	if req.Payload != nil {
		if tenantID == "" {
			tenantID = stringFromAny(req.Payload["tenant_id"])
		}
		if ownerUID == "" {
			ownerUID = stringFromAny(req.Payload["owner_uid"])
		}
	}
	scope := strings.TrimSpace(req.Scope)
	if ownerUID == "" && scope == "user" {
		ownerUID = strings.TrimSpace(req.ScopeID)
	}
	return tenantID, ownerUID
}

func buildDedupeKey(template *entity.Template, scope, scopeID string, payload map[string]any) string {
	parts := []string{template.Type, scope}
	for _, key := range template.DedupeKeys {
		switch key {
		case "scope_id":
			parts = append(parts, scopeID)
		case "target":
			if payload != nil {
				if target, ok := payload["target"].(string); ok {
					parts = append(parts, target)
				}
			}
		case "benchmark_username":
			if payload != nil {
				if username, ok := payload["benchmark_username"].(string); ok {
					parts = append(parts, username)
				}
			}
		}
	}
	raw := strings.Join(parts, "|")
	sum := sha256.Sum256([]byte(raw))
	return hex.EncodeToString(sum[:])
}

func firstPhaseFromTemplateSteps(steps []entity.StepProgress) string {
	if len(steps) == 0 {
		return ""
	}
	return steps[0].ID
}

func firstPhaseFromTemplate(template *entity.Template) string {
	if len(template.Steps) == 0 {
		return ""
	}
	return template.Steps[0].ID
}

func buildStepProgress(template *entity.Template) []entity.StepProgress {
	steps := make([]entity.StepProgress, 0, len(template.Steps))
	for _, step := range template.Steps {
		steps = append(steps, entity.StepProgress{ID: step.ID, Status: enum.StepStatusPending})
	}
	return steps
}

func workerTypeFromTemplate(template *entity.Template) string {
	if len(template.Steps) > 0 && strings.TrimSpace(template.Steps[0].WorkerType) != "" {
		return template.Steps[0].WorkerType
	}
	return string(enum.WorkerTypeGo)
}

func (u *jobUseCase) appendEvent(ctx context.Context, jobID, eventType, from, to, message string, metadata map[string]any) error {
	return u.events.Append(ctx, &entity.Event{
		JobID:    jobID,
		Type:     eventType,
		From:     from,
		To:       to,
		Message:  message,
		Metadata: metadata,
	})
}

func (u *jobUseCase) enqueueRun(ctx context.Context, run *entity.Run) (*entity.Run, error) {
	jobID := run.ID.Hex()
	if run.ScheduledAt != nil && *run.ScheduledAt > clock.NowUnixNano() {
		return run, nil
	}
	if err := u.queue.Enqueue(ctx, run.WorkerType, jobID); err != nil {
		return nil, err
	}
	fromStatus := string(run.Status)
	run.Status = enum.RunStatusQueued
	updated, err := u.runs.Update(ctx, run)
	if err != nil {
		return nil, err
	}
	_ = u.appendEvent(ctx, jobID, "status_changed", fromStatus, string(enum.RunStatusQueued), "job enqueued", nil)
	return updated, nil
}

func (u *jobUseCase) releaseDedupe(ctx context.Context, run *entity.Run) {
	if run.DedupeKey == "" {
		return
	}
	_ = u.queue.ReleaseDedupe(ctx, run.TemplateType, run.DedupeKey)
}

func (u *jobUseCase) enforceDedupe(ctx context.Context, template *entity.Template, dedupeKey string) error {
	if dedupeKey == "" {
		return nil
	}
	if !template.Repeatable {
		existing, err := u.runs.FindSucceededByDedupeKey(ctx, template.Type, dedupeKey)
		if err != nil {
			return err
		}
		if existing != nil {
			return app.For(code.Job).ResInvalidState("job already completed for dedupe key")
		}
	}
	return nil
}

func (u *jobUseCase) acquireDedupeLease(ctx context.Context, template *entity.Template, dedupeKey, jobID string) error {
	if dedupeKey == "" {
		return nil
	}
	ttl := template.TimeoutSeconds
	if ttl <= 0 {
		ttl = 3600
	}
	ok, err := u.queue.TryAcquireDedupe(ctx, template.Type, dedupeKey, jobID, ttl)
	if err != nil {
		return err
	}
	if !ok {
		return app.For(code.Job).ResInvalidState("duplicate job already in progress")
	}
	return nil
}

func retryBackoffSeconds(template *entity.Template, attempt int) int {
	if len(template.RetryPolicy.BackoffSeconds) == 0 {
		return 0
	}
	idx := attempt - 2
	if idx < 0 {
		idx = 0
	}
	if idx >= len(template.RetryPolicy.BackoffSeconds) {
		idx = len(template.RetryPolicy.BackoffSeconds) - 1
	}
	return template.RetryPolicy.BackoffSeconds[idx]
}