package httpapi

import (
	"errors"
	"net/http"
	"strconv"

	"evobgp/internal/runtimelogs"
	"evobgp/internal/store"
)

func (s *Server) registerRuntimeLogsRoutes(m *http.ServeMux) {
	m.HandleFunc("GET /runtime-logs/files", s.handleListRuntimeLogFiles)
	m.HandleFunc("GET /runtime-logs/files/{filename}", s.handleGetRuntimeLogTail)
	m.HandleFunc("DELETE /runtime-logs/files/{filename}", s.handleDeleteRuntimeLogFile)
	m.HandleFunc("GET /runtime-logs/cleanup-audit", s.handleListRuntimeLogCleanupAudit)
	m.HandleFunc("GET /runtime-logs/auto-estimate", s.handleRuntimeLogAutoEstimate)
	m.HandleFunc("POST /runtime-logs/auto-run", s.handleRuntimeLogAutoRun)
}

func (s *Server) requireRuntimeLogs(w http.ResponseWriter) bool {
	if s.runtimeLogs != nil && s.runtimeLogs.Available() {
		return true
	}
	writeProblem(w, http.StatusServiceUnavailable, "Unavailable", "runtime_logs_unavailable")
	return false
}

func writeRuntimeLogsErr(w http.ResponseWriter, operation string, err error) {
	switch {
	case errors.Is(err, runtimelogs.ErrUnavailable):
		writeProblem(w, http.StatusServiceUnavailable, "Unavailable", "runtime_logs_unavailable")
	case errors.Is(err, runtimelogs.ErrNotFound):
		writeProblem(w, http.StatusNotFound, "Not Found", notFoundDetail)
	case errors.Is(err, runtimelogs.ErrFileTooLarge):
		writeProblem(w, http.StatusRequestEntityTooLarge, "Payload Too Large", "file exceeds maximum size for cleanup")
	case errors.Is(err, runtimelogs.ErrInvalidFilename), errors.Is(err, runtimelogs.ErrNotAFile):
		writeProblem(w, http.StatusUnprocessableEntity, "Unprocessable Entity", invalidInputDetail)
	default:
		writeInternalError(w, operation, err)
	}
}

func runtimeLogFileJSON(f store.RuntimeLogFile) map[string]any {
	return map[string]any{
		"name":        f.Name,
		"size_bytes":  f.SizeBytes,
		"modified_at": f.ModifiedAt.UTC().Format("2006-01-02T15:04:05Z"),
	}
}

func runtimeLogCleanupAuditJSON(row *store.RuntimeLogCleanupAudit) map[string]any {
	out := map[string]any{
		"id":           row.ID,
		"tenant_id":    row.TenantID,
		"actor_prefix": row.ActorPrefix,
		"filename":     row.Filename,
		"action":       row.Action,
		"size_before":  row.SizeBefore,
		"created_at":   row.CreatedAt.UTC().Format("2006-01-02T15:04:05Z"),
	}
	if row.SizeAfter != nil {
		out["size_after"] = *row.SizeAfter
	}
	if row.Detail != nil {
		out["detail"] = row.Detail
	}
	return out
}

func (s *Server) handleListRuntimeLogFiles(w http.ResponseWriter, r *http.Request) {
	a, ok := authFromContext(r.Context())
	if !ok || !s.requirePerm(w, a, "bgp:monitoring:read") || !s.requireRuntimeLogs(w) {
		return
	}
	items, err := s.runtimeLogs.ListFiles()
	if err != nil {
		writeRuntimeLogsErr(w, "runtime_logs_list", err)
		return
	}
	out := make([]map[string]any, 0, len(items))
	for _, f := range items {
		out = append(out, runtimeLogFileJSON(f))
	}
	writeJSON(w, http.StatusOK, map[string]any{"items": out})
}

func (s *Server) handleGetRuntimeLogTail(w http.ResponseWriter, r *http.Request) {
	a, ok := authFromContext(r.Context())
	if !ok || !s.requirePerm(w, a, "bgp:monitoring:read") || !s.requireRuntimeLogs(w) {
		return
	}
	filename := r.PathValue("filename")
	opts := runtimelogs.TailOptions{
		Lines: parsePositiveIntQuery(r, "lines", runtimelogs.DefaultTailLines, runtimelogs.MaxTailLines),
		Bytes: parsePositiveIntQuery(r, "bytes", 0, runtimelogs.MaxTailBytes),
		Grep:  r.URL.Query().Get("grep"),
	}
	tail, err := s.runtimeLogs.Tail(filename, opts)
	if err != nil {
		writeRuntimeLogsErr(w, "runtime_logs_tail", err)
		return
	}
	writeJSON(w, http.StatusOK, map[string]any{
		"filename":       tail.Filename,
		"content":        tail.Content,
		"truncated":      tail.Truncated,
		"lines_returned": tail.LinesReturned,
	})
}

func (s *Server) handleDeleteRuntimeLogFile(w http.ResponseWriter, r *http.Request) {
	a, ok := authFromContext(r.Context())
	if !ok || !s.requirePerm(w, a, "bgp:tenant_settings:admin") || !s.requireRuntimeLogs(w) {
		return
	}
	filename := r.PathValue("filename")
	mode := r.URL.Query().Get("mode")
	if mode == "" {
		mode = store.RuntimeLogCleanupTruncate
	}
	if !store.ValidRuntimeLogCleanupAction(mode) {
		writeProblem(w, http.StatusUnprocessableEntity, "Unprocessable Entity", invalidInputDetail)
		return
	}
	sizeBefore, sizeAfter, err := s.runtimeLogs.Cleanup(filename, mode)
	if err != nil {
		writeRuntimeLogsErr(w, "runtime_logs_cleanup", err)
		return
	}
	auditID, err := s.store.AppendRuntimeLogCleanupAudit(
		a.TenantID, actorPrefix(a), filename, mode, sizeBefore, sizeAfter, nil)
	if err != nil {
		writeInternalError(w, "runtime_logs_cleanup_audit", err)
		return
	}
	out := map[string]any{
		"audit_id":    auditID,
		"filename":    filename,
		"action":      mode,
		"size_before": sizeBefore,
	}
	if sizeAfter != nil {
		out["size_after"] = *sizeAfter
	}
	writeJSON(w, http.StatusOK, out)
}

func (s *Server) runtimeLogAutoPolicy(w http.ResponseWriter, r *http.Request, tenantID string) (runtimelogs.AutoPolicy, bool) {
	settings, err := s.store.ListGlobalSettings(tenantID)
	if err != nil {
		writeInternalError(w, "runtime_logs_policy", err)
		return runtimelogs.AutoPolicy{}, false
	}
	return runtimelogs.PolicyFromSettings(settings), true
}

func (s *Server) handleRuntimeLogAutoEstimate(w http.ResponseWriter, r *http.Request) {
	a, ok := authFromContext(r.Context())
	if !ok || !s.requirePerm(w, a, "bgp:tenant_settings:admin") || !s.requireRuntimeLogs(w) {
		return
	}
	policy, ok := s.runtimeLogAutoPolicy(w, r, a.TenantID)
	if !ok {
		return
	}
	items, err := runtimelogs.EstimateAutoCleanup(s.runtimeLogs, policy)
	if err != nil {
		writeRuntimeLogsErr(w, "runtime_logs_auto_estimate", err)
		return
	}
	out := make([]map[string]any, 0, len(items))
	var wouldCount int
	for _, it := range items {
		if it.WouldCleanup {
			wouldCount++
		}
		row := map[string]any{
			"filename":      it.Filename,
			"size_bytes":    it.SizeBytes,
			"would_cleanup": it.WouldCleanup,
		}
		if it.SkipReason != "" {
			row["skip_reason"] = it.SkipReason
		}
		out = append(out, row)
	}
	writeJSON(w, http.StatusOK, map[string]any{
		"policy": map[string]any{
			"enabled":        policy.Enabled,
			"max_file_bytes": policy.MaxFileBytes,
			"schedule":       policy.Schedule,
			"mode":           policy.Mode,
		},
		"items":       out,
		"would_count": wouldCount,
	})
}

func (s *Server) handleRuntimeLogAutoRun(w http.ResponseWriter, r *http.Request) {
	a, ok := authFromContext(r.Context())
	if !ok || !s.requirePerm(w, a, "bgp:tenant_settings:admin") || !s.requireRuntimeLogs(w) {
		return
	}
	policy, ok := s.runtimeLogAutoPolicy(w, r, a.TenantID)
	if !ok {
		return
	}
	dryRun := r.URL.Query().Get("dry_run") == "true"
	result, err := runtimelogs.RunAutoCleanup(r.Context(), runtimelogs.AutoCleanupDeps{
		Service:  s.runtimeLogs,
		Store:    s.store,
		TenantID: a.TenantID,
	}, policy, dryRun, "manual")
	if err != nil {
		writeRuntimeLogsErr(w, "runtime_logs_auto_run", err)
		return
	}
	writeJSON(w, http.StatusOK, result)
}

func (s *Server) handleListRuntimeLogCleanupAudit(w http.ResponseWriter, r *http.Request) {
	a, ok := authFromContext(r.Context())
	if !ok || !s.requirePerm(w, a, "bgp:monitoring:read") {
		return
	}
	cursor := r.URL.Query().Get("cursor")
	limit := parseLimitQuery(r, 20, 100)
	items, next, hasMore, err := s.store.ListRuntimeLogCleanupAudit(a.TenantID, cursor, limit)
	if err != nil {
		writeInternalError(w, "runtime_logs_cleanup_audit_list", err)
		return
	}
	out := make([]map[string]any, 0, len(items))
	for _, row := range items {
		out = append(out, runtimeLogCleanupAuditJSON(row))
	}
	writeJSON(w, http.StatusOK, map[string]any{"items": out, "next_cursor": next, "has_more": hasMore})
}

func parsePositiveIntQuery(r *http.Request, key string, def, max int) int {
	v := r.URL.Query().Get(key)
	if v == "" {
		return def
	}
	n, err := strconv.Atoi(v)
	if err != nil || n <= 0 {
		return def
	}
	if max > 0 && n > max {
		return max
	}
	return n
}