feat: embed genesis.json for known Sei chains

chains.go

@@ -0,0 +1,67 @@
+package seiconfig
+
+import (
+	"embed"
+	"fmt"
+	"path"
+)
+
+//go:embed chains/*/genesis.json
+var chainFS embed.FS
+
+// ChainInfo describes a well-known Sei network whose genesis is embedded in
+// this binary. Callers that need a chain not listed here must supply their own
+// genesis configuration.
+type ChainInfo struct {
+	ChainID     string
+	RPC         string
+	GenesisTime string
+}
+
+// knownChains is the authoritative set of chains with embedded genesis data.
+var knownChains = map[string]ChainInfo{
+	"pacific-1": {
+		ChainID:     "pacific-1",
+		RPC:         "https://rpc.sei-apis.com",
+		GenesisTime: "2023-05-22T15:00:00Z",
+	},
+	"atlantic-2": {
+		ChainID:     "atlantic-2",
+		RPC:         "https://rpc-testnet.sei-apis.com",
+		GenesisTime: "2023-02-24T01:00:00Z",
+	},
+	"arctic-1": {
+		ChainID:     "arctic-1",
+		RPC:         "https://rpc-arctic-1.sei-apis.com",
+		GenesisTime: "2024-01-25T20:18:30.242526108Z",
+	},
+}
+
+// KnownChain returns metadata for a well-known chain, or nil if the chain ID
+// is not recognised.
+func KnownChain(chainID string) *ChainInfo {
+	info, ok := knownChains[chainID]
+	if !ok {
+		return nil
+	}
+	return &info
+}
+
+// KnownChainIDs returns the set of chain IDs that have embedded genesis data.
+func KnownChainIDs() []string {
+	ids := make([]string, 0, len(knownChains))
+	for id := range knownChains {
+		ids = append(ids, id)
+	}
+	return ids
+}
+
+// GenesisForChain returns the embedded genesis.json bytes for a well-known
+// chain. Returns an error if the chain ID is not recognised — the caller must
+// provide their own genesis source for unknown chains.
+func GenesisForChain(chainID string) ([]byte, error) {
+	if _, ok := knownChains[chainID]; !ok {
+		return nil, fmt.Errorf("unknown chain %q: provide a custom genesis source", chainID)
+	}
+	return chainFS.ReadFile(path.Join("chains", chainID, "genesis.json"))
+}