package runtime

import "unsafe"

func plugin_lastmoduleinit() (path string, syms map[string]interface{}, errstr string) {
	var md *moduledata
	for pmd := firstmoduledata.next; pmd != nil; pmd = pmd.next {
		if pmd.bad {
			md = nil // we only want the last module
			continue
		}
		md = pmd
	}
	if md == nil {
		throw("runtime: no plugin module data")
	}
	if md.pluginpath == "" {
		throw("runtime: plugin has empty pluginpath")
	}
	if md.typemap != nil {
		return "", nil, "plugin already loaded"
	}

	for _, pmd := range activeModules() {
		if pmd.pluginpath == md.pluginpath {
			md.bad = true
			return "", nil, "plugin already loaded"
		}

		if inRange(pmd.text, pmd.etext, md.text, md.etext) ||
			inRange(pmd.bss, pmd.ebss, md.bss, md.ebss) ||
			inRange(pmd.data, pmd.edata, md.data, md.edata) ||
			inRange(pmd.types, pmd.etypes, md.types, md.etypes) {
			println("plugin: new module data overlaps with previous moduledata")
			println("\tpmd.text-etext=", hex(pmd.text), "-", hex(pmd.etext))
			println("\tpmd.bss-ebss=", hex(pmd.bss), "-", hex(pmd.ebss))
			println("\tpmd.data-edata=", hex(pmd.data), "-", hex(pmd.edata))
			println("\tpmd.types-etypes=", hex(pmd.types), "-", hex(pmd.etypes))
			println("\tmd.text-etext=", hex(md.text), "-", hex(md.etext))
			println("\tmd.bss-ebss=", hex(md.bss), "-", hex(md.ebss))
			println("\tmd.data-edata=", hex(md.data), "-", hex(md.edata))
			println("\tmd.types-etypes=", hex(md.types), "-", hex(md.etypes))
			throw("plugin: new module data overlaps with previous moduledata")
		}
	}
	for _, pkghash := range md.pkghashes {
		if pkghash.linktimehash != *pkghash.runtimehash {
			md.bad = true
			return "", nil, "plugin was built with a different version of package " + pkghash.modulename
		}
	}

	modulesinit()
	typelinksinit()

	pluginftabverify(md)
	moduledataverify1(md)

	lock(&itabLock)
	for _, i := range md.itablinks {
		itabAdd(i)
	}
	unlock(&itabLock)

	syms = make(map[string]interface{}, len(md.ptab))
	for _, ptab := range md.ptab {
		symName := resolveNameOff(unsafe.Pointer(md.types), ptab.name)
		t := (*_type)(unsafe.Pointer(md.types)).typeOff(ptab.typ)
		var val interface{}
		valp := (*[2]unsafe.Pointer)(unsafe.Pointer(&val))
		(*valp)[0] = unsafe.Pointer(t)

		name := symName.name()
		if t.kind&kindMask == kindFunc {
			name = "." + name
		}
		syms[name] = val
	}
	return md.pluginpath, syms, ""
}

func pluginftabverify(md *moduledata) {
	badtable := false
	for i := 0; i < len(md.ftab); i++ {
		entry := md.ftab[i].entry
		if md.minpc <= entry && entry <= md.maxpc {
			continue
		}

		f := funcInfo{(*_func)(unsafe.Pointer(&md.pclntable[md.ftab[i].funcoff])), md}
		name := funcname(f)

		name2 := "none"
		entry2 := uintptr(0)
		f2 := findfunc(entry)
		if f2.valid() {
			name2 = funcname(f2)
			entry2 = f2.entry
		}
		badtable = true
		println("ftab entry outside pc range: ", hex(entry), "/", hex(entry2), ": ", name, "/", name2)
	}
	if badtable {
		throw("runtime: plugin has bad symbol table")
	}
}

func inRange(r0, r1, v0, v1 uintptr) bool {
	return (v0 >= r0 && v0 <= r1) || (v1 >= r0 && v1 <= r1)
}

type ptabEntry struct {
	name nameOff
	typ  typeOff