package handler

import (
	"encoding/json"
	"log/slog"
	"net/http"

	"github.com/go-chi/chi/v5"
	"github.com/jackc/pgx/v5/pgtype"
	"github.com/multica-ai/multica/server/internal/logger"
	db "github.com/multica-ai/multica/server/pkg/db/generated"
	"github.com/multica-ai/multica/server/pkg/protocol"
)

type CommentResponse struct {
	ID         string  `json:"id"`
	IssueID    string  `json:"issue_id"`
	AuthorType string  `json:"author_type"`
	AuthorID   string  `json:"author_id"`
	Content    string  `json:"content"`
	Type       string  `json:"type"`
	ParentID   *string `json:"parent_id"`
	CreatedAt  string  `json:"created_at"`
	UpdatedAt  string  `json:"updated_at"`
}

func commentToResponse(c db.Comment) CommentResponse {
	return CommentResponse{
		ID:         uuidToString(c.ID),
		IssueID:    uuidToString(c.IssueID),
		AuthorType: c.AuthorType,
		AuthorID:   uuidToString(c.AuthorID),
		Content:    c.Content,
		Type:       c.Type,
		ParentID:   uuidToPtr(c.ParentID),
		CreatedAt:  timestampToString(c.CreatedAt),
		UpdatedAt:  timestampToString(c.UpdatedAt),
	}
}

func (h *Handler) ListComments(w http.ResponseWriter, r *http.Request) {
	issueID := chi.URLParam(r, "id")
	issue, ok := h.loadIssueForUser(w, r, issueID)
	if !ok {
		return
	}

	comments, err := h.Queries.ListComments(r.Context(), issue.ID)
	if err != nil {
		writeError(w, http.StatusInternalServerError, "failed to list comments")
		return
	}

	resp := make([]CommentResponse, len(comments))
	for i, c := range comments {
		resp[i] = commentToResponse(c)
	}

	writeJSON(w, http.StatusOK, resp)
}

type CreateCommentRequest struct {
	Content  string  `json:"content"`
	Type     string  `json:"type"`
	ParentID *string `json:"parent_id"`
}

func (h *Handler) CreateComment(w http.ResponseWriter, r *http.Request) {
	issueID := chi.URLParam(r, "id")
	issue, ok := h.loadIssueForUser(w, r, issueID)
	if !ok {
		return
	}

	userID, ok := requireUserID(w, r)
	if !ok {
		return
	}

	var req CreateCommentRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request body")
		return
	}

	if req.Content == "" {
		writeError(w, http.StatusBadRequest, "content is required")
		return
	}
	if req.Type == "" {
		req.Type = "comment"
	}

	var parentID pgtype.UUID
	if req.ParentID != nil {
		parentID = parseUUID(*req.ParentID)
		parent, err := h.Queries.GetComment(r.Context(), parentID)
		if err != nil || uuidToString(parent.IssueID) != issueID {
			writeError(w, http.StatusBadRequest, "invalid parent comment")
			return
		}
	}

	// Determine author identity: agent (via X-Agent-ID header) or member.
	authorType, authorID := h.resolveActor(r, userID, uuidToString(issue.WorkspaceID))

	comment, err := h.Queries.CreateComment(r.Context(), db.CreateCommentParams{
		IssueID:    issue.ID,
		AuthorType: authorType,
		AuthorID:   parseUUID(authorID),
		Content:    req.Content,
		Type:       req.Type,
		ParentID:   parentID,
	})
	if err != nil {
		slog.Warn("create comment failed", append(logger.RequestAttrs(r), "error", err, "issue_id", issueID)...)
		writeError(w, http.StatusInternalServerError, "failed to create comment: "+err.Error())
		return
	}

	resp := commentToResponse(comment)
	slog.Info("comment created", append(logger.RequestAttrs(r), "comment_id", uuidToString(comment.ID), "issue_id", issueID)...)
	h.publish(protocol.EventCommentCreated, uuidToString(issue.WorkspaceID), authorType, authorID, map[string]any{
		"comment":             resp,
		"issue_title":         issue.Title,
		"issue_assignee_type": textToPtr(issue.AssigneeType),
		"issue_assignee_id":   uuidToPtr(issue.AssigneeID),
		"issue_status":        issue.Status,
	})

	// If the issue is assigned to an agent with on_comment trigger, enqueue a new task.
	// Skip when the comment comes from the assigned agent itself to avoid loops.
	if authorType == "member" && h.shouldEnqueueOnComment(r.Context(), issue) {
		if _, err := h.TaskService.EnqueueTaskForIssue(r.Context(), issue); err != nil {
			slog.Warn("enqueue agent task on comment failed", "issue_id", issueID, "error", err)
		}
	}

	writeJSON(w, http.StatusCreated, resp)
}

func (h *Handler) UpdateComment(w http.ResponseWriter, r *http.Request) {
	commentId := chi.URLParam(r, "commentId")

	userID, ok := requireUserID(w, r)
	if !ok {
		return
	}

	// Load comment to check ownership
	existing, err := h.Queries.GetComment(r.Context(), parseUUID(commentId))
	if err != nil {
		writeError(w, http.StatusNotFound, "comment not found")
		return
	}

	// Load issue to get workspace
	issue, err := h.Queries.GetIssue(r.Context(), existing.IssueID)
	if err != nil {
		writeError(w, http.StatusNotFound, "comment not found")
		return
	}

	member, ok := h.requireWorkspaceMember(w, r, uuidToString(issue.WorkspaceID), "comment not found")
	if !ok {
		return
	}

	isAuthor := existing.AuthorType == "member" && uuidToString(existing.AuthorID) == userID
	isAdmin := roleAllowed(member.Role, "owner", "admin")
	if !isAuthor && !isAdmin {
		writeError(w, http.StatusForbidden, "only comment author or admin can edit")
		return
	}

	var req struct {
		Content string `json:"content"`
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request body")
		return
	}
	if req.Content == "" {
		writeError(w, http.StatusBadRequest, "content is required")
		return
	}

	comment, err := h.Queries.UpdateComment(r.Context(), db.UpdateCommentParams{
		ID:      parseUUID(commentId),
		Content: req.Content,
	})
	if err != nil {
		slog.Warn("update comment failed", append(logger.RequestAttrs(r), "error", err, "comment_id", commentId)...)
		writeError(w, http.StatusInternalServerError, "failed to update comment")
		return
	}

	resp := commentToResponse(comment)
	actorType, actorID := h.resolveActor(r, userID, uuidToString(issue.WorkspaceID))
	slog.Info("comment updated", append(logger.RequestAttrs(r), "comment_id", commentId)...)
	h.publish(protocol.EventCommentUpdated, uuidToString(issue.WorkspaceID), actorType, actorID, map[string]any{"comment": resp})
	writeJSON(w, http.StatusOK, resp)
}

func (h *Handler) DeleteComment(w http.ResponseWriter, r *http.Request) {
	commentId := chi.URLParam(r, "commentId")

	userID, ok := requireUserID(w, r)
	if !ok {
		return
	}

	// Get the comment first to know the issue_id for the broadcast
	comment, err := h.Queries.GetComment(r.Context(), parseUUID(commentId))
	if err != nil {
		writeError(w, http.StatusNotFound, "comment not found")
		return
	}

	// Load issue to get workspace
	issue, err := h.Queries.GetIssue(r.Context(), comment.IssueID)
	if err != nil {
		writeError(w, http.StatusNotFound, "comment not found")
		return
	}

	member, ok := h.requireWorkspaceMember(w, r, uuidToString(issue.WorkspaceID), "comment not found")
	if !ok {
		return
	}

	isAuthor := comment.AuthorType == "member" && uuidToString(comment.AuthorID) == userID
	isAdmin := roleAllowed(member.Role, "owner", "admin")
	if !isAuthor && !isAdmin {
		writeError(w, http.StatusForbidden, "only comment author or admin can delete")
		return
	}

	if err := h.Queries.DeleteComment(r.Context(), parseUUID(commentId)); err != nil {
		slog.Warn("delete comment failed", append(logger.RequestAttrs(r), "error", err, "comment_id", commentId)...)
		writeError(w, http.StatusInternalServerError, "failed to delete comment")
		return
	}

	actorType, actorID := h.resolveActor(r, userID, uuidToString(issue.WorkspaceID))
	slog.Info("comment deleted", append(logger.RequestAttrs(r), "comment_id", commentId, "issue_id", uuidToString(comment.IssueID))...)
	h.publish(protocol.EventCommentDeleted, uuidToString(issue.WorkspaceID), actorType, actorID, map[string]any{
		"comment_id": commentId,
		"issue_id":   uuidToString(comment.IssueID),
	})
	w.WriteHeader(http.StatusNoContent)
}