// Copyright (C) 2024  Umorpha Systems
// SPDX-License-Identifier: AGPL-3.0-or-later

package leader

import (
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"git.mothstuff.lol/lukeshu/eclipse/lib/common"
)

// Main config /////////////////////////////////////////////////////////////////

type Config struct {
	PubKeyFile string `json:"pubkey_file"`

	StateDir   string `json:"state_dir"`
	CacheDir   string `json:"cache_dir"`
	ActionsDir string `json:"actions_dir"`

	GitCacheFor       common.Duration `json:"cache_git_for"`
	ParallelDownloads int             `json:"parallel_downloads"`
}

func LoadConfig(filename string) (Config, error) {
	return common.LoadYAML[Config](filename)
}

// Actions /////////////////////////////////////////////////////////////////////

type Action struct {
	Triggers []Trigger `json:"triggers"`
	Run      string    `json:"run"`
}

type Trigger struct {
	// GitRev triggers once for each matching rev.
	//
	// For example, given the config
	//
	//	rev="refs/tags/v*"
	//
	// and the refs
	//
	//	"refs/tags/v1" => 0001
	//	"refs/tags/v2" => 0002
	//	"refs/tags/v3" => 0003
	//
	// it would trigger 3 times:
	//
	//	{"git_rev":{"url":"…","rev":"refs/tags/v1"}} => 0001
	//	{"git_rev":{"url":"…","rev":"refs/tags/v2"}} => 0002
	//	{"git_rev":{"url":"…","rev":"refs/tags/v3"}} => 0003
	GitRev *struct {
		URL string `json:"url"`
		Rev string `json:"rev"`
	} `json:"git_rev,omitempty"`

	// GitRevs triggers once with the list of all matching revs.
	//
	// For example, given the config
	//
	//	revs="refs/tags/v*"
	//
	// and the refs
	//
	//	"refs/tags/v1" => 0001
	//	"refs/tags/v2" => 0002
	//	"refs/tags/v3" => 0003
	//
	// it would trigger just once:
	//
	//	{"git_revs:"{"url":"…","revs":"refs/tags/v*"}} => "refs/tags/v1\t0001\nrefs/tags/v2\t0002\nrefs/tags/v3\t0003"
	GitRevs *struct {
		URL  string `json:"url"`
		Revs string `json:"revs"`
	} `json:"git_revs,omitempty"`
}

func (trigger *Trigger) UnmarshalJSON(dat []byte) error {
	type untypedTrigger Trigger
	var obj untypedTrigger
	if err := json.Unmarshal(dat, &obj); err != nil {
		return err
	}
	cnt := 0
	if obj.GitRev != nil {
		cnt++
	}
	if obj.GitRevs != nil {
		cnt++
	}
	if cnt != 1 {
		return fmt.Errorf("trigger must have exactly 1 field set")
	}
	*trigger = Trigger(obj)
	return nil
}

func (cfg Config) Actions() ([]Action, error) {
	entries, err := os.ReadDir(cfg.ActionsDir)
	if err != nil {
		return nil, err
	}
	var ret []Action
	for _, entry := range entries {
		if !strings.HasSuffix(entry.Name(), ".yml") && !strings.HasSuffix(entry.Name(), ".yaml") {
			continue
		}
		actions, err := common.LoadYAML[[]Action](filepath.Join(cfg.ActionsDir, entry.Name()))
		if err != nil {
			return nil, fmt.Errorf("%q: %w", entry.Name(), err)
		}
		ret = append(ret, actions...)
	}
	return ret, nil
}