package spec

import (
	"encoding/json"
	"os"

	"forge.cadoles.com/Cadoles/emissary/internal/client"
	agentFlag "forge.cadoles.com/Cadoles/emissary/internal/command/client/agent/flag"
	"forge.cadoles.com/Cadoles/emissary/internal/command/client/apierr"
	clientFlag "forge.cadoles.com/Cadoles/emissary/internal/command/client/flag"
	"forge.cadoles.com/Cadoles/emissary/internal/format"
	"forge.cadoles.com/Cadoles/emissary/internal/spec"
	jsonpatch "github.com/evanphx/json-patch/v5"
	"github.com/pkg/errors"
	"github.com/urfave/cli/v2"

	// Import specs
	_ "forge.cadoles.com/Cadoles/emissary/internal/spec/app"
	_ "forge.cadoles.com/Cadoles/emissary/internal/spec/gateway"
	_ "forge.cadoles.com/Cadoles/emissary/internal/spec/uci"
)

func UpdateCommand() *cli.Command {
	return &cli.Command{
		Name:  "update",
		Usage: "Update agent specification",
		Flags: agentFlag.WithAgentFlags(
			&cli.StringFlag{
				Name:  "spec-name",
				Usage: "use `NAME` as spec name",
			},
			&cli.StringFlag{
				Name:  "spec-data",
				Usage: "use `DATA` as spec data, '-' to read from STDIN",
			},
			&cli.BoolFlag{
				Name:  "no-patch",
				Usage: "Dont use spec-data as a patch to existing specification",
			},
			&cli.IntFlag{
				Name:  "revision",
				Usage: "Use `REVISION` as specification revision number",
			},
		),
		Action: func(ctx *cli.Context) error {
			baseFlags := clientFlag.GetBaseFlags(ctx)
			agentID, err := agentFlag.AssertAgentID(ctx)
			if err != nil {
				return errors.WithStack(err)
			}

			specName, err := assertSpecName(ctx)
			if err != nil {
				return errors.WithStack(err)
			}

			specData, err := assertSpecData(ctx)
			if err != nil {
				return errors.WithStack(err)
			}

			noPatch := ctx.Bool("no-patch")

			token, err := clientFlag.GetToken(baseFlags)
			if err != nil {
				return errors.WithStack(apierr.Wrap(err))
			}

			client := client.New(baseFlags.ServerURL, client.WithToken(token))

			specs, err := client.GetAgentSpecs(ctx.Context, agentID)
			if err != nil {
				return errors.WithStack(apierr.Wrap(err))
			}

			var existingSpec spec.Spec

			for _, s := range specs {
				if s.SpecName() != specName {
					continue
				}

				existingSpec = s

				break
			}

			revision := 0

			if existingSpec != nil {
				originSpecData := existingSpec.SpecData()

				if !noPatch {
					specData, err = applyPatch(originSpecData, specData)
					if err != nil {
						return errors.WithStack(err)
					}
				}

				revision = existingSpec.SpecRevision()
			}

			if specificRevision := ctx.Int("revision"); specificRevision != 0 {
				revision = specificRevision
			}

			rawSpec := &spec.RawSpec{
				Name:     specName,
				Revision: revision,
				Data:     specData,
			}

			if err := spec.Validate(ctx.Context, rawSpec); err != nil {
				return errors.WithStack(apierr.Wrap(err))
			}

			spec, err := client.UpdateAgentSpec(ctx.Context, agentID, rawSpec)
			if err != nil {
				return errors.WithStack(apierr.Wrap(err))
			}

			hints := format.Hints{
				OutputMode: baseFlags.OutputMode,
			}

			if err := format.Write(baseFlags.Format, os.Stdout, hints, spec); err != nil {
				return errors.WithStack(err)
			}

			return nil
		},
	}
}

func assertSpecName(ctx *cli.Context) (spec.Name, error) {
	specName := ctx.String("spec-name")

	if specName == "" {
		return "", errors.New("flag 'spec-name' is required")
	}

	return spec.Name(specName), nil
}

func assertSpecData(ctx *cli.Context) (map[string]any, error) {
	rawSpecData := ctx.String("spec-data")

	if rawSpecData == "" {
		return nil, errors.New("flag 'spec-data' is required")
	}

	var specData map[string]any

	if rawSpecData == "-" {
		decoder := json.NewDecoder(os.Stdin)
		if err := decoder.Decode(&specData); err != nil {
			return nil, errors.WithStack(err)
		}
	} else {
		if err := json.Unmarshal([]byte(rawSpecData), &specData); err != nil {
			return nil, errors.WithStack(err)
		}
	}

	return specData, nil
}

func applyPatch(origin any, patch any) (map[string]any, error) {
	originJSON, err := json.Marshal(origin)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	patchJSON, err := json.Marshal(patch)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	result, err := jsonpatch.MergePatch(originJSON, patchJSON)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	var specData map[string]any

	if err := json.Unmarshal(result, &specData); err != nil {
	}

	return specData, nil
}