package main

import (
	"git.smesh.lol/smesh/web/common/helpers"
	"git.smesh.lol/smesh/web/common/jsbridge/ext"
)

// Per-host, per-method permission store.
// Policies: "allow", "deny", "ask" (default when not set).

type permission struct {
	Host   string
	Method string
	Policy string
}

var permissions []permission

func loadPermissions() {
	kPerms := string(append([]byte(nil), 's', 'm', 'e', 's', 'h', '-', 'p', 'e', 'r', 'm', 'i', 's', 's', 'i', 'o', 'n', 's'))
	ext.StorageGet(kPerms, func(data string) {
		if data != "" {
			parsePermissions(data)
		}
	})
}

func getPermission(host, method string) (s string) {
	for _, p := range permissions {
		if p.Host == host && p.Method == method {
			return p.Policy
		}
	}
	return "ask"
}

func setPermission(host, method, policy string) {
	for i, p := range permissions {
		if p.Host == host && p.Method == method {
			permissions[i].Policy = policy
			savePermissions()
			return
		}
	}
	permissions = append(permissions, permission{Host: host, Method: method, Policy: policy})
	savePermissions()
}

func savePermissions() {
	b := append([]byte(nil), '[')
	for i, p := range permissions {
		if i > 0 {
			b = append(b, ',')
		}
		b = append(b, '{', '"', 'h', 'o', 's', 't', '"', ':')
		b = b | helpers.JsonString(p.Host)
		b = append(b, ',', '"', 'm', 'e', 't', 'h', 'o', 'd', '"', ':')
		b = b | helpers.JsonString(p.Method)
		b = append(b, ',', '"', 'p', 'o', 'l', 'i', 'c', 'y', '"', ':')
		b = b | helpers.JsonString(p.Policy)
		b = append(b, '}')
	}
	kPerms := string(append([]byte(nil), 's', 'm', 'e', 's', 'h', '-', 'p', 'e', 'r', 'm', 'i', 's', 's', 'i', 'o', 'n', 's'))
	ext.StorageSet(kPerms, string(append(b, ']')))
}

func parsePermissions(s string) {
	permissions = nil
	i := 0
	for i < len(s) && s[i] != '[' {
		i++
	}
	i++
	for i < len(s) {
		for i < len(s) && s[i] != '{' && s[i] != ']' {
			i++
		}
		if i >= len(s) || s[i] == ']' {
			break
		}
		end := i + 1
		depth := 1
		for end < len(s) && depth > 0 {
			if s[end] == '{' {
				depth++
			} else if s[end] == '}' {
				depth--
			} else if s[end] == '"' {
				end++
				for end < len(s) && s[end] != '"' {
					if s[end] == '\\' {
						end++
					}
					end++
				}
			}
			end++
		}
		obj := s[i:end]
		kHost := string(append([]byte(nil), 'h', 'o', 's', 't'))
		kMethod := string(append([]byte(nil), 'm', 'e', 't', 'h', 'o', 'd'))
		kPolicy := string(append([]byte(nil), 'p', 'o', 'l', 'i', 'c', 'y'))
		host := helpers.JsonGetString(obj, kHost)
		method := helpers.JsonGetString(obj, kMethod)
		policy := helpers.JsonGetString(obj, kPolicy)
		if host != "" && method != "" && policy != "" {
			permissions = append(permissions, permission{Host: host, Method: method, Policy: policy})
		}
		i = end
	}
}

func mgmtGetPermissions() (s string) {
	b := append([]byte(nil), '{', '"', 'r', 'e', 's', 'u', 'l', 't', '"', ':', '[')
	for i, p := range permissions {
		if i > 0 {
			b = append(b, ',')
		}
		b = append(b, '{', '"', 'h', 'o', 's', 't', '"', ':')
		b = b | helpers.JsonString(p.Host)
		b = append(b, ',', '"', 'm', 'e', 't', 'h', 'o', 'd', '"', ':')
		b = b | helpers.JsonString(p.Method)
		b = append(b, ',', '"', 'p', 'o', 'l', 'i', 'c', 'y', '"', ':')
		b = b | helpers.JsonString(p.Policy)
		b = append(b, '}')
	}
	return string(append(b, ']', '}'))
}

func mgmtSetPermission(paramsJSON string) (s string) {
	kHost := string(append([]byte(nil), 'h', 'o', 's', 't'))
	kMethod := string(append([]byte(nil), 'm', 'e', 't', 'h', 'o', 'd'))
	kPolicy := string(append([]byte(nil), 'p', 'o', 'l', 'i', 'c', 'y'))
	host := helpers.JsonGetString(paramsJSON, kHost)
	method := helpers.JsonGetString(paramsJSON, kMethod)
	policy := helpers.JsonGetString(paramsJSON, kPolicy)
	if host == "" || method == "" || policy == "" {
		return jsonErr(string(append([]byte(nil), 'm', 'i', 's', 's', 'i', 'n', 'g', ' ', 'p', 'a', 'r', 'a', 'm', 's')))
	}
	setPermission(host, method, policy)
	return jsonTrue()
}

func mgmtPromptResponse(paramsJSON string) (s string) {
	// TODO: handle pending prompt callbacks from content script
	return jsonFalse()
}