package rpc

import (
	"encoding/json"
	"fmt"
	"strings"

	"github.com/steveyegge/beads/internal/types"
	"github.com/steveyegge/beads/internal/utils"
)

// normalizeLabels trims whitespace, removes empty strings, and deduplicates labels
func normalizeLabels(ss []string) []string {
	seen := make(map[string]struct{})
	out := make([]string, 0, len(ss))
	for _, s := range ss {
		s = strings.TrimSpace(s)
		if s == "" {
			continue
		}
		if _, ok := seen[s]; ok {
			continue
		}
		seen[s] = struct{}{}
		out = append(out, s)
	}
	return out
}

func strValue(p *string) string {
	if p == nil {
		return ""
	}
	return *p
}

func updatesFromArgs(a UpdateArgs) map[string]interface{} {
	u := map[string]interface{}{}
	if a.Title != nil {
		u["title"] = *a.Title
	}
	if a.Description != nil {
		u["description"] = *a.Description
	}
	if a.Status != nil {
		u["status"] = *a.Status
	}
	if a.Priority != nil {
		u["priority"] = *a.Priority
	}
	if a.Design != nil {
		u["design"] = a.Design
	}
	if a.AcceptanceCriteria != nil {
		u["acceptance_criteria"] = a.AcceptanceCriteria
	}
	if a.Notes != nil {
		u["notes"] = a.Notes
	}
	if a.Assignee != nil {
		u["assignee"] = a.Assignee
	}
	return u
}

func (s *Server) handleCreate(req *Request) Response {
	var createArgs CreateArgs
	if err := json.Unmarshal(req.Args, &createArgs); err != nil {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("invalid create args: %v", err),
		}
	}

	store := s.storage

	var design, acceptance, assignee *string
	if createArgs.Design != "" {
		design = &createArgs.Design
	}
	if createArgs.AcceptanceCriteria != "" {
		acceptance = &createArgs.AcceptanceCriteria
	}
	if createArgs.Assignee != "" {
		assignee = &createArgs.Assignee
	}

	issue := &types.Issue{
		ID:                 createArgs.ID,
		Title:              createArgs.Title,
		Description:        createArgs.Description,
		IssueType:          types.IssueType(createArgs.IssueType),
		Priority:           createArgs.Priority,
		Design:             strValue(design),
		AcceptanceCriteria: strValue(acceptance),
		Assignee:           strValue(assignee),
		Status:             types.StatusOpen,
	}

	ctx := s.reqCtx(req)
	if err := store.CreateIssue(ctx, issue, s.reqActor(req)); err != nil {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("failed to create issue: %v", err),
		}
	}

	// Add labels if specified
	for _, label := range createArgs.Labels {
		if err := store.AddLabel(ctx, issue.ID, label, s.reqActor(req)); err != nil {
			return Response{
				Success: false,
				Error:   fmt.Sprintf("failed to add label %s: %v", label, err),
			}
		}
	}

	// Add dependencies if specified
	for _, depSpec := range createArgs.Dependencies {
		depSpec = strings.TrimSpace(depSpec)
		if depSpec == "" {
			continue
		}

		var depType types.DependencyType
		var dependsOnID string

		if strings.Contains(depSpec, ":") {
			parts := strings.SplitN(depSpec, ":", 2)
			if len(parts) != 2 {
				return Response{
					Success: false,
					Error:   fmt.Sprintf("invalid dependency format '%s', expected 'type:id' or 'id'", depSpec),
				}
			}
			depType = types.DependencyType(strings.TrimSpace(parts[0]))
			dependsOnID = strings.TrimSpace(parts[1])
		} else {
			depType = types.DepBlocks
			dependsOnID = depSpec
		}

		if !depType.IsValid() {
			return Response{
				Success: false,
				Error:   fmt.Sprintf("invalid dependency type '%s' (valid: blocks, related, parent-child, discovered-from)", depType),
			}
		}

		dep := &types.Dependency{
			IssueID:     issue.ID,
			DependsOnID: dependsOnID,
			Type:        depType,
		}
		if err := store.AddDependency(ctx, dep, s.reqActor(req)); err != nil {
			return Response{
				Success: false,
				Error:   fmt.Sprintf("failed to add dependency %s -> %s: %v", issue.ID, dependsOnID, err),
			}
		}
	}

	// Emit mutation event for event-driven daemon
	s.emitMutation(MutationCreate, issue.ID)

	data, _ := json.Marshal(issue)
	return Response{
		Success: true,
		Data:    data,
	}
}

func (s *Server) handleUpdate(req *Request) Response {
	var updateArgs UpdateArgs
	if err := json.Unmarshal(req.Args, &updateArgs); err != nil {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("invalid update args: %v", err),
		}
	}

	store := s.storage

	ctx := s.reqCtx(req)
	updates := updatesFromArgs(updateArgs)
	if len(updates) == 0 {
		return Response{Success: true}
	}

	if err := store.UpdateIssue(ctx, updateArgs.ID, updates, s.reqActor(req)); err != nil {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("failed to update issue: %v", err),
		}
	}

	// Emit mutation event for event-driven daemon
	s.emitMutation(MutationUpdate, updateArgs.ID)

	issue, err := store.GetIssue(ctx, updateArgs.ID)
	if err != nil {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("failed to get updated issue: %v", err),
		}
	}

	data, _ := json.Marshal(issue)
	return Response{
		Success: true,
		Data:    data,
	}
}

func (s *Server) handleClose(req *Request) Response {
	var closeArgs CloseArgs
	if err := json.Unmarshal(req.Args, &closeArgs); err != nil {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("invalid close args: %v", err),
		}
	}

	store := s.storage

	ctx := s.reqCtx(req)
	if err := store.CloseIssue(ctx, closeArgs.ID, closeArgs.Reason, s.reqActor(req)); err != nil {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("failed to close issue: %v", err),
		}
	}

	// Emit mutation event for event-driven daemon
	s.emitMutation(MutationUpdate, closeArgs.ID)

	issue, _ := store.GetIssue(ctx, closeArgs.ID)
	data, _ := json.Marshal(issue)
	return Response{
		Success: true,
		Data:    data,
	}
}

func (s *Server) handleList(req *Request) Response {
	var listArgs ListArgs
	if err := json.Unmarshal(req.Args, &listArgs); err != nil {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("invalid list args: %v", err),
		}
	}

	store := s.storage

	filter := types.IssueFilter{
		Limit: listArgs.Limit,
	}
	if listArgs.Status != "" {
		status := types.Status(listArgs.Status)
		filter.Status = &status
	}
	if listArgs.IssueType != "" {
		issueType := types.IssueType(listArgs.IssueType)
		filter.IssueType = &issueType
	}
	if listArgs.Assignee != "" {
		filter.Assignee = &listArgs.Assignee
	}
	if listArgs.Priority != nil {
		filter.Priority = listArgs.Priority
	}
	// Normalize and apply label filters
	labels := normalizeLabels(listArgs.Labels)
	labelsAny := normalizeLabels(listArgs.LabelsAny)
	// Support both old single Label and new Labels array
	if len(labels) > 0 {
		filter.Labels = labels
	} else if listArgs.Label != "" {
		filter.Labels = []string{strings.TrimSpace(listArgs.Label)}
	}
	if len(labelsAny) > 0 {
		filter.LabelsAny = labelsAny
	}
	if len(listArgs.IDs) > 0 {
		ids := normalizeLabels(listArgs.IDs)
		if len(ids) > 0 {
			filter.IDs = ids
		}
	}

	// Guard against excessive ID lists to avoid SQLite parameter limits
	const maxIDs = 1000
	if len(filter.IDs) > maxIDs {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("--id flag supports at most %d issue IDs, got %d", maxIDs, len(filter.IDs)),
		}
	}

	ctx := s.reqCtx(req)
	issues, err := store.SearchIssues(ctx, listArgs.Query, filter)
	if err != nil {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("failed to list issues: %v", err),
		}
	}

	// Populate labels for each issue
	for _, issue := range issues {
		labels, _ := store.GetLabels(ctx, issue.ID)
		issue.Labels = labels
	}

	// Get dependency counts in bulk (single query instead of N queries)
	issueIDs := make([]string, len(issues))
	for i, issue := range issues {
		issueIDs[i] = issue.ID
	}
	depCounts, _ := store.GetDependencyCounts(ctx, issueIDs)

	// Build response with counts
	issuesWithCounts := make([]*types.IssueWithCounts, len(issues))
	for i, issue := range issues {
		counts := depCounts[issue.ID]
		if counts == nil {
			counts = &types.DependencyCounts{DependencyCount: 0, DependentCount: 0}
		}
		issuesWithCounts[i] = &types.IssueWithCounts{
			Issue:           issue,
			DependencyCount: counts.DependencyCount,
			DependentCount:  counts.DependentCount,
		}
	}

	data, _ := json.Marshal(issuesWithCounts)
	return Response{
		Success: true,
		Data:    data,
	}
}

func (s *Server) handleResolveID(req *Request) Response {
	var args ResolveIDArgs
	if err := json.Unmarshal(req.Args, &args); err != nil {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("invalid resolve_id args: %v", err),
		}
	}

	ctx := s.reqCtx(req)
	resolvedID, err := utils.ResolvePartialID(ctx, s.storage, args.ID)
	if err != nil {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("failed to resolve ID: %v", err),
		}
	}

	data, _ := json.Marshal(resolvedID)
	return Response{
		Success: true,
		Data:    data,
	}
}

func (s *Server) handleShow(req *Request) Response {
	var showArgs ShowArgs
	if err := json.Unmarshal(req.Args, &showArgs); err != nil {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("invalid show args: %v", err),
		}
	}

	store := s.storage

	ctx := s.reqCtx(req)
	issue, err := store.GetIssue(ctx, showArgs.ID)
	if err != nil {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("failed to get issue: %v", err),
		}
	}

	// Populate labels, dependencies, and dependents
	labels, _ := store.GetLabels(ctx, issue.ID)
	deps, _ := store.GetDependencies(ctx, issue.ID)
	dependents, _ := store.GetDependents(ctx, issue.ID)

	// Create detailed response with related data
	type IssueDetails struct {
		*types.Issue
		Labels       []string       `json:"labels,omitempty"`
		Dependencies []*types.Issue `json:"dependencies,omitempty"`
		Dependents   []*types.Issue `json:"dependents,omitempty"`
	}

	details := &IssueDetails{
		Issue:        issue,
		Labels:       labels,
		Dependencies: deps,
		Dependents:   dependents,
	}

	data, _ := json.Marshal(details)
	return Response{
		Success: true,
		Data:    data,
	}
}

func (s *Server) handleReady(req *Request) Response {
	var readyArgs ReadyArgs
	if err := json.Unmarshal(req.Args, &readyArgs); err != nil {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("invalid ready args: %v", err),
		}
	}

	store := s.storage

	wf := types.WorkFilter{
		Status:     types.StatusOpen,
		Priority:   readyArgs.Priority,
		Limit:      readyArgs.Limit,
		SortPolicy: types.SortPolicy(readyArgs.SortPolicy),
	}
	if readyArgs.Assignee != "" {
		wf.Assignee = &readyArgs.Assignee
	}

	ctx := s.reqCtx(req)
	issues, err := store.GetReadyWork(ctx, wf)
	if err != nil {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("failed to get ready work: %v", err),
		}
	}

	data, _ := json.Marshal(issues)
	return Response{
		Success: true,
		Data:    data,
	}
}

func (s *Server) handleStale(req *Request) Response {
	var staleArgs StaleArgs
	if err := json.Unmarshal(req.Args, &staleArgs); err != nil {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("invalid stale args: %v", err),
		}
	}

	store := s.storage

	filter := types.StaleFilter{
		Days:   staleArgs.Days,
		Status: staleArgs.Status,
		Limit:  staleArgs.Limit,
	}

	ctx := s.reqCtx(req)
	issues, err := store.GetStaleIssues(ctx, filter)
	if err != nil {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("failed to get stale issues: %v", err),
		}
	}

	data, _ := json.Marshal(issues)
	return Response{
		Success: true,
		Data:    data,
	}
}

func (s *Server) handleStats(req *Request) Response {
	store := s.storage

	ctx := s.reqCtx(req)
	stats, err := store.GetStatistics(ctx)
	if err != nil {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("failed to get statistics: %v", err),
		}
	}

	data, _ := json.Marshal(stats)
	return Response{
		Success: true,
		Data:    data,
	}
}

func (s *Server) handleEpicStatus(req *Request) Response {
	var epicArgs EpicStatusArgs
	if err := json.Unmarshal(req.Args, &epicArgs); err != nil {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("invalid epic status args: %v", err),
		}
	}

	store := s.storage

	ctx := s.reqCtx(req)
	epics, err := store.GetEpicsEligibleForClosure(ctx)
	if err != nil {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("failed to get epic status: %v", err),
		}
	}

	if epicArgs.EligibleOnly {
		filtered := []*types.EpicStatus{}
		for _, epic := range epics {
			if epic.EligibleForClose {
				filtered = append(filtered, epic)
			}
		}
		epics = filtered
	}

	data, err := json.Marshal(epics)
	if err != nil {
		return Response{
			Success: false,
			Error:   fmt.Sprintf("failed to marshal epics: %v", err),
		}
	}

	return Response{
		Success: true,
		Data:    data,
	}
}