package main

import (
	"cmp"
	"errors"
	"fmt"
	"isle/daemon/daecommon"
	"slices"

	"golang.org/x/exp/maps"
)

type storageAllocation struct {
	Index                             int `yaml:"index"`
	daecommon.ConfigStorageAllocation `yaml:",inline"`
}

func indexStorageAllocations(
	config daecommon.NetworkConfig,
) []storageAllocation {
	slices.SortFunc(
		config.Storage.Allocations,
		func(i, j daecommon.ConfigStorageAllocation) int {
			return cmp.Compare(i.RPCPort, j.RPCPort)
		},
	)

	allocs := make([]storageAllocation, len(config.Storage.Allocations))
	for i := range config.Storage.Allocations {
		allocs[i] = storageAllocation{i, config.Storage.Allocations[i]}
	}

	return allocs
}

var subCmdStorageAllocationAdd = subCmd{
	name:  "add-allocation",
	descr: "Adds a new storage allocation to the host",
	do: func(ctx subCmdCtx) error {
		var alloc daecommon.ConfigStorageAllocation

		ctx.flags.StringVar(
			&alloc.DataPath,
			"data-path",
			"",
			"Path to the directory data should be stored in",
		)

		ctx.flags.StringVar(
			&alloc.MetaPath,
			"meta-path",
			"",
			"Path to the directory metadata should be stored in. This is a"+
				" smaller dataset which benefits from a faster drive, if"+
				" possible.",
		)

		ctx.flags.IntVar(
			&alloc.Capacity,
			"capacity",
			0,
			"How many gigabytes to allocate.",
		)

		ctx.flags.IntVar(
			&alloc.S3APIPort,
			"s3-api-port",
			0,
			"Which port of the VPN network interface to serve the S3 API on."+
				" Will be automatically assigned if not given.",
		)

		ctx.flags.IntVar(
			&alloc.RPCPort,
			"rpc-port",
			0,
			"Which port of the VPN network interface to serve RPC requests on."+
				" Will be automatically assigned if not given. Once this port"+
				" is defined for an allocation it cannot be changed.",
		)

		ctx.flags.IntVar(
			&alloc.AdminPort,
			"admin-port",
			0,
			"Which port of the VPN network interface to serve admin requests"+
				" on. Will be automatically assigned if not given.",
		)

		ctx, err := ctx.withParsedFlags(nil)
		if err != nil {
			return fmt.Errorf("parsing flags: %w", err)
		}

		if alloc.DataPath == "" || alloc.MetaPath == "" || alloc.Capacity == 0 {
			return errors.New(
				"--data-path, --meta-path, and --capacity are required",
			)
		}

		config, err := ctx.daemonRPC.GetConfig(ctx)
		if err != nil {
			return fmt.Errorf("getting network config: %w", err)
		}

		config.Storage.Allocations = append(config.Storage.Allocations, alloc)

		if err := ctx.daemonRPC.SetConfig(ctx, config); err != nil {
			return fmt.Errorf("updating the network config: %w", err)
		}

		return nil
	},
}

var subCmdStorageAllocationList = subCmd{
	name:   "list-allocation",
	plural: "s",
	descr:  "Lists all storage which is currently allocated on this host",
	do: doWithOutput(func(ctx subCmdCtx) (any, error) {
		ctx, err := ctx.withParsedFlags(nil)
		if err != nil {
			return nil, fmt.Errorf("parsing flags: %w", err)
		}

		config, err := ctx.daemonRPC.GetConfig(ctx)
		if err != nil {
			return nil, fmt.Errorf("getting network config: %w", err)
		}

		return indexStorageAllocations(config), nil
	}),
}

var subCmdStorageAllocationRemove = subCmd{
	name: "remove-allocation",
	descr: "Removes an allocation which has been previously added. " +
		"Allocations are identified by their index field from the output of " +
		"`storage list-allocation(s)`.",
	do: func(ctx subCmdCtx) error {
		indexes := ctx.flags.IntSlice(
			"index", nil,
			"Index of the storage allocation which should be removed. Can be "+
				"specified more than once",
		)

		ctx, err := ctx.withParsedFlags(nil)
		if err != nil {
			return fmt.Errorf("parsing flags: %w", err)
		}

		if len(*indexes) == 0 {
			return errors.New("At least one --index must be specified")
		}

		config, err := ctx.daemonRPC.GetConfig(ctx)
		if err != nil {
			return fmt.Errorf("getting network config: %w", err)
		}

		var (
			allocs        = indexStorageAllocations(config)
			allocsByIndex = map[int]daecommon.ConfigStorageAllocation{}
		)

		for _, alloc := range allocs {
			allocsByIndex[alloc.Index] = alloc.ConfigStorageAllocation
		}

		for _, index := range *indexes {
			if _, ok := allocsByIndex[index]; !ok {
				return fmt.Errorf(
					"Index %d not found in configured storage allocations: %w",
					index, err,
				)
			}
			delete(allocsByIndex, index)
		}

		// we sort the new allocation set so that tests are deterministic
		newAllocs := maps.Values(allocsByIndex)
		slices.SortFunc(
			newAllocs,
			func(i, j daecommon.ConfigStorageAllocation) int {
				return cmp.Compare(i.RPCPort, j.RPCPort)
			},
		)

		config.Storage.Allocations = newAllocs
		if err := ctx.daemonRPC.SetConfig(ctx, config); err != nil {
			return fmt.Errorf("updating the network config: %w", err)
		}

		return nil
	},
}

var subCmdStorage = subCmd{
	name:  "storage",
	descr: "Sub-commands related to configuration of storage on this host",
	do: func(ctx subCmdCtx) error {
		return ctx.doSubCmd(
			subCmdStorageAllocationAdd,
			subCmdStorageAllocationList,
			subCmdStorageAllocationRemove,
		)
	},
}