package server

import (
	"errors"
	"net/http"
	"os"
	"path/filepath"
	"time"

	"chat-agent-system/internal/controlcenter/pipeline"
	"chat-agent-system/internal/controlcenter/tasks"
)

// handleTaskExportDoc renders a task as a .doc short-term task document and
// writes it to <RepoRoot>/.doc/ops/short-term/YYYY-MM-DD-<slug>.md. The
// periodic docs sync then indexes it like any other .doc file. An existing
// file is never overwritten (409).
func (s *Server) handleTaskExportDoc(w http.ResponseWriter, r *http.Request) {
	id := r.PathValue("id")
	t, err := tasks.GetTask(r.Context(), s.store, id)
	if err != nil {
		writeDomainError(w, err)
		return
	}
	if !tasks.ValidDocSlug(t.Slug) {
		writeError(w, http.StatusBadRequest, "task slug is not exportable: must match [a-z0-9-]+")
		return
	}

	today := time.Now().Format("2006-01-02")
	rel := filepath.Join(".doc", "ops", "short-term", today+"-"+t.Slug+".md")
	full := filepath.Join(s.cfg.RepoRoot, rel)
	if err := os.MkdirAll(filepath.Dir(full), 0o755); err != nil {
		writeDomainError(w, err)
		return
	}
	f, err := os.OpenFile(full, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0o644)
	if errors.Is(err, os.ErrExist) {
		writeError(w, http.StatusConflict, "doc file already exists: "+filepath.ToSlash(rel))
		return
	}
	if err != nil {
		writeDomainError(w, err)
		return
	}
	if _, err := f.WriteString(tasks.RenderTaskDoc(t, today)); err != nil {
		f.Close()
		writeDomainError(w, err)
		return
	}
	if err := f.Close(); err != nil {
		writeDomainError(w, err)
		return
	}

	relSlash := filepath.ToSlash(rel)
	t, err = tasks.PatchTask(r.Context(), s.store, id, tasks.Patch{DocPath: &relSlash})
	if err != nil {
		writeDomainError(w, err)
		return
	}
	s.appendEvent(r.Context(), id, "", pipeline.PhaseSystem, "exported doc "+relSlash, nil)
	writeJSON(w, http.StatusCreated, map[string]any{"doc_path": relSlash, "task": t})
}