package service

import (
	"context"
	"fmt"
	"strconv"

	"gcy_hpc_server/internal/model"
	"gcy_hpc_server/internal/slurm"

	"go.uber.org/zap"
)

func derefStr(s *string) string {
	if s == nil {
		return ""
	}
	return *s
}

func derefInt32(i *int32) int32 {
	if i == nil {
		return 0
	}
	return *i
}

func derefInt64(i *int64) int64 {
	if i == nil {
		return 0
	}
	return *i
}

func uint32NoValString(v *slurm.Uint32NoVal) string {
	if v == nil {
		return ""
	}
	if v.Infinite != nil && *v.Infinite {
		return "UNLIMITED"
	}
	if v.Number != nil {
		return strconv.FormatInt(*v.Number, 10)
	}
	return ""
}

type ClusterService struct {
	client *slurm.Client
	logger *zap.Logger
}

func NewClusterService(client *slurm.Client, logger *zap.Logger) *ClusterService {
	return &ClusterService{client: client, logger: logger}
}

func (s *ClusterService) GetNodes(ctx context.Context) ([]model.NodeResponse, error) {
	resp, _, err := s.client.Nodes.GetNodes(ctx, nil)
	if err != nil {
		s.logger.Error("failed to get nodes", zap.Error(err))
		return nil, fmt.Errorf("get nodes: %w", err)
	}
	if resp.Nodes == nil {
		return nil, nil
	}
	result := make([]model.NodeResponse, 0, len(*resp.Nodes))
	for _, n := range *resp.Nodes {
		result = append(result, mapNode(n))
	}
	return result, nil
}

func (s *ClusterService) GetNode(ctx context.Context, name string) (*model.NodeResponse, error) {
	resp, _, err := s.client.Nodes.GetNode(ctx, name, nil)
	if err != nil {
		s.logger.Error("failed to get node", zap.String("name", name), zap.Error(err))
		return nil, fmt.Errorf("get node %s: %w", name, err)
	}
	if resp.Nodes == nil || len(*resp.Nodes) == 0 {
		return nil, nil
	}
	n := (*resp.Nodes)[0]
	mapped := mapNode(n)
	return &mapped, nil
}

func (s *ClusterService) GetPartitions(ctx context.Context) ([]model.PartitionResponse, error) {
	resp, _, err := s.client.Partitions.GetPartitions(ctx, nil)
	if err != nil {
		s.logger.Error("failed to get partitions", zap.Error(err))
		return nil, fmt.Errorf("get partitions: %w", err)
	}
	if resp.Partitions == nil {
		return nil, nil
	}
	result := make([]model.PartitionResponse, 0, len(*resp.Partitions))
	for _, pi := range *resp.Partitions {
		result = append(result, mapPartition(pi))
	}
	return result, nil
}

func (s *ClusterService) GetPartition(ctx context.Context, name string) (*model.PartitionResponse, error) {
	resp, _, err := s.client.Partitions.GetPartition(ctx, name, nil)
	if err != nil {
		s.logger.Error("failed to get partition", zap.String("name", name), zap.Error(err))
		return nil, fmt.Errorf("get partition %s: %w", name, err)
	}
	if resp.Partitions == nil || len(*resp.Partitions) == 0 {
		return nil, nil
	}
	p := (*resp.Partitions)[0]
	mapped := mapPartition(p)
	return &mapped, nil
}

func (s *ClusterService) GetDiag(ctx context.Context) (*slurm.OpenapiDiagResp, error) {
	resp, _, err := s.client.Diag.GetDiag(ctx)
	if err != nil {
		s.logger.Error("failed to get diag", zap.Error(err))
		return nil, fmt.Errorf("get diag: %w", err)
	}
	return resp, nil
}

func mapNode(n slurm.Node) model.NodeResponse {
	return model.NodeResponse{
		Name:       derefStr(n.Name),
		State:      n.State,
		CPUs:       derefInt32(n.Cpus),
		RealMemory: derefInt64(n.RealMemory),
		AllocMem:   derefInt64(n.AllocMemory),
		Arch:       derefStr(n.Architecture),
		OS:         derefStr(n.OperatingSystem),
	}
}

func mapPartition(pi slurm.PartitionInfo) model.PartitionResponse {
	var state []string
	if pi.Partition != nil {
		state = pi.Partition.State
	}
	var nodes string
	if pi.Nodes != nil {
		nodes = derefStr(pi.Nodes.Configured)
	}
	var totalCPUs int32
	if pi.CPUs != nil {
		totalCPUs = derefInt32(pi.CPUs.Total)
	}
	var totalNodes int32
	if pi.Nodes != nil {
		totalNodes = derefInt32(pi.Nodes.Total)
	}
	var maxTime string
	if pi.Maximums != nil {
		maxTime = uint32NoValString(pi.Maximums.Time)
	}
	return model.PartitionResponse{
		Name:       derefStr(pi.Name),
		State:      state,
		Nodes:      nodes,
		TotalCPUs:  totalCPUs,
		TotalNodes: totalNodes,
		MaxTime:    maxTime,
	}
}