package main

import (
	"bytes"
	"context"
	"fmt"
	"io/ioutil"
	"time"

	"git.sigsum.org/sigsum-lib-go/pkg/requests"
	"git.sigsum.org/sigsum-lib-go/pkg/types"
	"git.sigsum.org/sigsum-tools-go/pkg/client"
	"git.sigsum.org/sigsum-tools-go/pkg/policy"
	"git.sigsum.org/sigsum-tools-go/pkg/signatures"
	"git.sigsum.org/sigsum-tools-go/pkg/signatures/minisign"
	"git.sigsum.org/sigsum-tools-go/pkg/signatures/signify"
	"git.sigsum.org/sigsum-tools-go/pkg/signatures/ssh"
)

func cmdVerify(args []string, policy policy.Policy, optVerifyType, optVerifyKey string) error {
	return fmt.Errorf("TODO")
}

func cmdBundle(args []string, policy policy.Policy, optBundleType, optBundleKey, optBundleDomainHint string) error {
	if len(args) == 0 {
		return fmt.Errorf("bundle: need at least one file")
	}

	var parser signatures.Parser
	switch optBundleType {
	case "signify":
		parser = &signify.Parser{}
	case "minisign":
		parser = &minisign.Parser{}
	case "ssh":
		parser = &ssh.Parser{}
	default:
		return fmt.Errorf("bundle: invalid key type %q", optBundleType)
	}

	b, err := ioutil.ReadFile(optBundleKey)
	if err != nil {
		return fmt.Errorf("bundle: failed reading file %q: %v", optBundleKey, err)
	}
	pub, err := parser.PublicKey(bytes.NewBuffer(b))
	if err != nil {
		return fmt.Errorf("bundle: %v", err)
	}
	// TODO: check that domain hint is valid for public key

	var reqs []requests.Leaf
	for _, path := range args {
		preimage, err := fileHash(path)
		if err != nil {
			return fmt.Errorf("bundle: %v", err)
		}

		sigPath := path + parser.SignatureSuffix()
		b, err := ioutil.ReadFile(sigPath)
		if err != nil {
			return fmt.Errorf("bundle: failed reading file %q: %v", sigPath, err)
		}
		sig, err := parser.Signature(bytes.NewBuffer(b))
		if err != nil {
			return fmt.Errorf("bundle: %v", err)
		}

		req := requests.Leaf{
			ShardHint:       policy.ShardHint(),
			Preimage:        *preimage,
			Signature:       *sig,
			VerificationKey: *pub,
			DomainHint:      optBundleDomainHint,
		}

		stmt := types.Statement{
			ShardHint: req.ShardHint,
			Checksum:  *types.HashFn(req.Preimage[:]),
		}
		if !stmt.Verify(&req.VerificationKey, &req.Signature) {
			return fmt.Errorf("bundle: invalid signature for file %q", path)
		}
		reqs = append(reqs, req)
	}

	sc := client.NewSubmitClient(policy)
	ctx, cancel := context.WithTimeout(context.Background(), 15*time.Minute)
	defer cancel()
	bundles, err := sc.AddLeaves(ctx, reqs)
	if err != nil {
		return fmt.Errorf("bundle: %v", err)
	}

	// TODO: verify bundles
	// TODO: write to files
	fmt.Printf("got %d bundles\n", len(bundles))
	return nil
}

func cmdFormat(args []string, policy policy.Policy) error {
	if len(args) != 1 {
		return fmt.Errorf("format: need exactly one file")
	}

	preimage, err := fileHash(args[0])
	if err != nil {
		return fmt.Errorf("format: %v", err)
	}
	stmt := types.Statement{
		ShardHint: policy.ShardHint(),
		Checksum:  *types.HashFn(preimage[:]),
	}

	fmt.Printf("%s", stmt.ToBinary())
	return nil
}

func cmdNamespace(args []string, policy policy.Policy) error {
	if len(args) != 0 {
		return fmt.Errorf("namespace: got trailing arguments")
	}

	fmt.Printf("tree_leaf:v0:%d@sigsum.org", policy.ShardHint())
	return nil
}

// TODO: don't read full file into memory at once
func fileHash(path string) (*types.Hash, error) {
	b, err := ioutil.ReadFile(path)
	if err != nil {
		return nil, fmt.Errorf("failed reading file %q", path)
	}
	return types.HashFn(b), nil
}