package agents

import (
	"context"
	"fmt"
	"log/slog"
	"strings"

	"g.fc.run/ai/byre/internal/api"
	"g.fc.run/ai/byre/internal/git"
)

func (m *Manager) SetAuditWorkflow(ctx context.Context, projectID, name, actor string) (api.Project, error) {
	name = strings.TrimSpace(name)
	if name != "" {
		_, err := m.store.GetWorkflow(ctx, name)
		if err != nil {
			return api.Project{}, err
		}
		project, err := m.store.GetProject(ctx, projectID)
		if err != nil {
			return api.Project{}, err
		}
		creator, err := m.store.GetUser(ctx, project.CreatedBy)
		if err != nil {
			return api.Project{}, err
		}
		if creator.GitName == "" || creator.GitEmail == "" {
			return api.Project{}, fmt.Errorf("%w: audits run as the project's creator %s, who has no git identity", ErrInvalid, creator.Login)
		}
	}
	p, err := m.store.SetAuditWorkflow(ctx, projectID, name, actor)
	if err != nil {
		return api.Project{}, err
	}
	go m.audit(p.Id)
	return p, nil
}

func (m *Manager) auditAll(ctx context.Context) {
	projects, err := m.store.ListProjects(ctx)
	if err != nil {
		slog.Error("start audits", "err", err)
		return
	}
	for _, p := range projects {
		tasks, err := m.store.ListTasks(ctx, p.Id)
		if err != nil {
			slog.Error("start audits", "project", p.Id, "err", err)
			continue
		}
		for _, t := range tasks {
			if t.Status == api.TaskStatusActive && t.Background && t.State == api.TaskStateDiscardSuggested {
				m.dismissAudit(t.Id)
			}
		}
		m.audit(p.Id)
	}
}

func (m *Manager) audit(projectID string) {
	err := m.startAudit(context.Background(), projectID)
	if err != nil {
		slog.Error("start audit", "project", projectID, "err", err)
	}
}

func (m *Manager) startAudit(ctx context.Context, projectID string) error {
	m.auditMu.Lock()
	defer m.auditMu.Unlock()

	project, err := m.store.GetProject(ctx, projectID)
	if err != nil || project.AuditWorkflow == "" {
		return err
	}
	last, active, err := m.store.LastAudit(ctx, projectID)
	if err != nil || active {
		return err
	}
	head, err := git.BranchHead(project.RepoPath, project.DefaultBranch)
	if err != nil {
		return err
	}
	if head == last {
		return nil
	}
	creator, err := m.store.GetUser(ctx, project.CreatedBy)
	if err != nil {
		return err
	}
	tasks, err := m.StartWorkflow(ctx, project, creator, "Audit of "+short(head), head, "byre", project.AuditWorkflow, auditBrief(project.DefaultBranch, head), nil, head)
	if err == nil {
		slog.Info("audit started", "project", projectID, "commit", head, "workflow", project.AuditWorkflow)
		return nil
	}
	for _, t := range tasks {
		m.auditError(ctx, t, fmt.Sprintf("The audit of %s didn't start: %v. Discard this task to let audits continue; the next commit on %s starts one.", short(head), err, project.DefaultBranch))
	}
	return err
}

func (m *Manager) auditError(ctx context.Context, task api.Task, msg string) {
	err := m.store.AppendEvent(ctx, api.Event{
		Kind:      "session.error",
		ProjectId: &task.ProjectId,
		TaskId:    &task.Id,
		Actor:     "byre",
		Payload:   map[string]any{"error": msg},
	})
	if err != nil {
		slog.Error("record audit error", "task", task.Id, "err", err)
	}
}

func auditBrief(branch, commit string) string {
	return fmt.Sprintf("Audit of %s at %s. This isn't a review of a change: check the whole codebase as it stands against the project's standards and expectations, and fix what falls short. "+
		"byre runs this task in the background: the human doesn't see it until you ask a question, call ready_for_merge or hit an error. "+
		"Finish your stage with finish_stage as usual, even when you found nothing. Once the workflow has finished, byre asks whether the task is ready to merge; "+
		"if nothing needed changing, answer with suggest_discard, and byre discards the task without bothering the human.", branch, commit)
}

func (m *Manager) dismissAudit(taskID string) {
	ctx := context.Background()
	task, err := m.store.GetTask(ctx, taskID)
	if err != nil {
		slog.Error("dismiss audit", "task", taskID, "err", err)
		return
	}
	if !task.Background || task.Status != api.TaskStatusActive {
		return
	}
	finished, err := m.store.WorkflowFinished(ctx, *task.WorkflowRun)
	if err != nil {
		slog.Error("dismiss audit", "task", taskID, "err", err)
		return
	}
	if !finished {
		return
	}
	_, err = m.Discard(ctx, task, "byre")
	if err != nil {
		slog.Error("dismiss audit", "task", taskID, "err", err)
		return
	}
	slog.Info("audit dismissed itself", "task", taskID)
}